Remove unnecessary sounds from online audio. How to remove noise from a photo

How to understand what noise is in a photograph, if we are used to hearing it, but not seeing it. Various types of interference often appear in the speaker or headphones. Audible noise occurs due to a wave transmission failure. You can see color distortions in the photo or on the camera display, they look like fine-grained dust of a dark color if it is monochrome, or like multi-colored dots if the noise is colored. In small quantities, such effects can even embellish a photo if they look like the author’s idea. But most often they are the result incorrect settings camera and lack of lighting when shooting.

Thus, noise is an integral part of photography; without it, there are no photographs at all. It is impossible to completely get rid of noise. Its level and quantity are important. It produces noise when there is insufficient lighting in some areas of the photo. With an increase in the level of light absorption, that is, the ISO indicator, the noise decreases, but along with it the sharpness can also “go away”. It turns out that the changes are interconnected. If you choose between them, it is better to add noise to the picture than to lose the sharpness of the picture.

Blurred frames will definitely go to waste; it will be difficult to do anything with them, but pixel “garbage” can be removed or reduced to an acceptable appearance using special programs, plugins and graphic editors.

There are 2 fundamentally different types of noise in photography – monochrome and color.

1. Monochrome is directly related to sharpness and shows up as light and dark areas in a photo.
2. Color noise is associated with color saturation and contrast, and appears in the form of multi-colored spots and halos around objects.

How to prevent noise in photos

The struggle for image quality consists of finding a balance between the amount of noise and the sharpness of the image. The best option It is considered to avoid excess during the filming process. There are a number of tips and measures for this.

• To work, choose a camera with a high-quality matrix, a stabilization system, noise reduction and high light sensitivity. It will not be possible to completely remove noise, but reducing its intensity significantly is quite simple.

Modern cameras and matrices are aimed at minimizing the destructive effects of interference. Light-sensitive lenses help you take high-quality photos in low light conditions. Here, even high ISO values ​​will look decent right up to large-format printing.

• Shoot in RAW format. Every camera manufacturer has own format to save frames during shooting. But it is precisely this format that allows unbroken pixels and areas not subject to noise to be “pulled out” during post-processing. For each point, enough information is saved to allow you to edit the image in many ways.

It is almost impossible to correct a photo taken in JPEG format with noise. The programs will help to lightly wipe down the areas, but it will be quite difficult to make them high quality. An out-of-focus image, regardless of format, cannot be corrected.

• Use the lowest ISO possible. As the light absorption parameter increases, the amount of interference entering the matrix also increases, especially in low light conditions. Good camera or a light-sensitive lens can smooth out this effect, but it cannot be completely removed. Shoot with the lowest possible ISO values, at night or in the evening - the optimal value is 100.

• Avoid overheating the camera. In the summer or during long periods of shooting, all camera elements heat up and interference increases. Take breaks, shoot from under sun visors, and let the camera cool down often. At slow shutter speeds and in LiveView mode, the sensor heats up a little more, take this into account when planning your shooting. Then the noise will appear less in the pictures.

• Temperature– is far from the most important parameter at the time of shooting, but all other things being equal it will make a noticeable difference in the result. Humidity and direct sunlight also have a negative impact on image quality.

• Use a tripod for photography. Camera stabilization reduces the amount of noise on the sensor, therefore reducing digital noise. In low visibility conditions, at higher ISO values ​​or at long shutter speeds, grain, dark or blown out areas may appear. A tripod must be chosen to suit the weight of the camera with a margin, with the ability to rotate in 3 planes, at least.
• Take test shots before work. You can shoot static objects for an unlimited time; take test shots and evaluate the noise level. This approach will allow you to notice flaws and obstacles in advance and correct them before the photo shoot begins.
• Use a histogram. Modern cameras are equipped with a function that displays a histogram on the display during operation. Track peaks, highlight overexposed or overly dark areas already at the shooting stage, so that you can adjust the settings before conversion and post-processing.
• Think about the composition of the shot in advance. Some image problems only come to light when the picture is enlarged, cropped, or cropped. To avoid this problem, you need to check the compositions in the frame in advance. Then you won't have to cut it in the editor.

Camera settings and specifications will avoid the appearance of excessive brightness and color noise. But it is completely impossible to get rid of them without losing quality and sharpness. To reduce the intensity of noise, you can use special programs.

Noise reduction programs

Photographers who have been processing photographs for a long time also have tools for retouching and processing “raw” images. There are dozens of such programs, applications or plugins, with 4-5 popular ones. They are used by more than 95% of users.

Here, the undoubted championship is held by the program from the Adobe System - Photoshop, followed by its brother - Lightroom. There are two more popular converters that have an excellent algorithm for reducing noise of any type - Capture One Digital Photo Professional from Canon.

• Adobe Photoshop. Undoubtedly the most popular program for photography enthusiasts and professional photographers. In Photoshop, you can remove noise at the conversion stage or during post-processing. The program is superimposed with a plugin - Adobe Camera RAW for converting images from the camera for direct work in Photoshop. Even if you saved the frames in JPEG format, this program will help “rewrite” them into RAW.
• Adobe Lightroom. Another program from the creator of Photoshop, it was originally created for archiving, organizing and storing pictures on a PC. Then primary processing was added to its functions. All new versions are equipped with more and more functionality; today it is not much inferior to other photo editing programs.

• Capture One. The noise reduction function is built into the program; it automatically cleans the image when converting from the camera. The peculiarity of Capture One is its intelligent operation; depending on the degree of noise, the intensity of processing is adjusted. With good sharpness and interference, the intervention of the program algorithm is minimal. Both brightness and color noise are processed; the latter are gently removed without the formation of halos around objects.
• Digital Photo Professional from Canon. A program for converting RAW format images from a camera to a PC. At the same time, chromatic and luminance noise, if any, is removed. If necessary, you can disable it in the program settings.

The last 2 programs have a narrow focus and are not suitable for artistic processing; they are created for converting images from the RAW format of the camera. Both Lightroom and Adobe Camera RAW were created for similar purposes, but then their functionality expanded significantly.

Learn more about Lightroom

The Lightroom program is an indispensable assistant for a photographer; its capabilities include working with images: converting from RAW, adjusting sharpness, contrast, adjusting white balance, adjusting colors and brightness. In the functionality of the program, if there is a Noise Reduction tab, noise is divided into 2 types and each can be tightened separately. Luminance is responsible for brightness interference, and Color is responsible for color interference. This way you can tidy up the pixels before loading them into Photoshop for artistic processing.

Each of the tools includes 3 sliders, for Luminance: Brightness, Detail and Contrast; at Color: Color, Detail and Transitions. By moving the sliders, you can reduce the brightness, intensity and severity of grain, as well as increase the sharpness of individual elements.

If you need to work with an area of ​​the image, and not with the entire image, then use the following tools:

• Radial Filter;
  Gradient Filter;
  Adjustment Brush.

Representing sliders, these tools allow you to gently adjust the sharpness and noise level in a selected area without changing the picture as a whole. If the use of parameters has a negative impact on sharpness, you can correct the situation with the Sharpening tool. The movement of the slider changes the sharpness of the image, and to prevent the noise from returning, use “Masking”. The mask allows you to keep the boundaries of objects sharp, getting rid of noise.

How to remove noise in Photoshop

The most popular graphics editor does not deal with noise as professionally as less popular programs. All because this function is not essential for Photoshop.

The “Reduce Noise” filter is responsible for “noise”, where you can select a basic level of or advanced. The first one makes manipulations on all channels simultaneously, reducing the intensity of noise with relative stability of sharpness. In advanced mode, you can manually make changes for each channel separately. You can change the following parameters:

• Brightness or noise intensity (Strenght);
  Preserve Details;
  Color noise intensity (Reduce Color Noise);
  Sharpen Details.

For more professional and subtle work with noise in photographs, you can use Adobe plugin Camera RAW. It installs on Photoshop and acts as a converter with additional noise reduction during processing. In terms of functionality, the plugin significantly outperforms the built-in filter; tangible advantages include:

• The ability to apply the results obtained to similar photographs, for example, from the same photo shoot;
• Finer and more precise pixel cleaning without compromising image quality;
• The performance of the plugin is fast, since it does not require downloading the editor itself to work.
  The Adobe Camera Raw plugin was created for photographers, it is thought out quite well and is quickly learned even with basic knowledge of Photoshop and editing.

How to remove noise from a photo. Let's sum it up

All noise reduction programs perform similar actions in the process of reducing the intensity of interference and noise in the image. Any of the listed programs may be suitable for each photo at different times. With their help, luminance (light or dark pixels) and color (bright pixels of contrasting colors) noise are removed.

Working with them is quite simple: you can trust the manufacturers’ developments and their algorithms, or you can manually clean the image. Any of these manipulations requires, at a minimum, an understanding of the process, and, at a maximum, all the subtleties of the influence of each item from the settings.

As a rule, experienced photographers have been using one of the programs for a long time and are unlikely to trade convenience for newfangled gadgets, and for beginners it doesn’t matter which program they use to learn editing. Each program has advantages in some area, as well as disadvantages. But the development of digital photography is taking place in huge leaps, offering another “discovery” every six months.

Manufacturers are releasing new versions of already known programs, developing fundamentally new tools, cameras are becoming smarter, and matrices are becoming more complex. In this case, digital noise will soon become a curiosity and will be considered an artistic effect and the author's intention.

In the understanding of uninitiated users, audio editing means converting discs to MP3 or FLAC, as well as cutting tracks from a disc image with a CUE markup file. The most advanced “pros” can even make ringtones by cutting out a fragment they like from a musical composition. These are, of course, quite popular actions, but the term “sound processing” has a completely different meaning.

How can I change the sound? First of all, you can influence frequency characteristics audio signal. Frequency correction is akin to a sharpening filter when processing an image - visually the object is made clearer and more legible, but this does not mean that details have been added after editing. When processing frequencies sound signal roughly the same thing happens. I suppose everyone who wore headphones with a player sometimes felt the need to “tweak the equalizer” to add bass or pull out the high frequencies. But what’s interesting is that strongly protruded high frequencies increased noise, which did not decorate the audio track. The reverse procedure—noise suppression using frequency equalization—has a different problem. Along with the noise, a certain spectrum of vocals and music disappears, which leads to loss useful information.

Another way to “change” the sound is through the use of effects. In our opinion, such a sound processing technique is justified only when the sound engineer is working on mixing audio material and has a clear idea of ​​what he is doing. Sometimes even a distortion filter can make an audio fragment sound natural. In addition, audio filters often help to hide or veil some defects in the audio track. For example, if there is a strange sound or echo at the end of a recorded instrument part, you can correct this by cutting out or muting the problem area and “immersing” the ending in a smooth echo with a decay effect.

There is a third way to edit digital audio. This is what the sound processing principle in most modern audio editors is based on. For the original recording, a waveform is created - a diagram from which you can visually trace the change in sound amplitude over time. If you open any audio file in a sound editor, such as Sound Forge or Goldwave, you will see that this is the default sound representation option in the program. Modern sound editing packages allow you to make changes to the shape of this “sine wave” - change the shape of the peaks, compress or expand them, remove fragments and modify the nature of the curve. This opens up wide possibilities for the user who sets out to process sound: in the original audio material in the wave form, you can easily find clicks and noise, and then remove them, etc.

Noise is one of the most pressing problems encountered in audio processing. Noise is a natural phenomenon. It is present everywhere and in everything - water gurgles from the tap in the kitchen, cars make noise on the street, computers and printers hum in the office. Accompanies noise and any audio recording, be it a message on an answering machine or musical compositions from an audio disc. Of course, the noise level in all these cases varies, however, it is impossible to completely get rid of it. The nature of noise can be very different - from the buzzing of a drill to the rustling of leaves, so it is impossible to come up with an ideal algorithm that would clear sound from noise. In addition, audio interference is akin to dust and scratches in a photograph - artifacts can be “masked” as the main sound and made less noticeable, or rather inaudible, and can be removed completely.

The most important question that faces users is which tool to choose to combat noise? The choice of a sound processing tool depends on financial preferences. Of course, there are professional applications that use unique audio processing algorithms and cost thousands of dollars. The capabilities of specialized software can be much wider and not limited to noise removal alone. For example, some apps may remove certain sounds from the audio track, such as the occasional noise of a passing car. However, this option can only be afforded by large companies, say, film studios, which have a fairly substantial budget at their disposal. For a user with an average income, a pretty good option is Sound Forge Pro or Adobe Audition. Well, as an economy option, we can offer it, but it must be the latest version, even if it is a beta version. Don't be afraid of the editor's test version. In fact, this program works very stably and is no worse than the official release. In addition, it has some tools that were clearly missing in the previous version.

⇡ Removing noise in pauses between audio tracks in Sound Forge Pro

This professional audio processing package contains two key tools to help you beat noise. The first one is called Noise Gate. Imagine an old recording from an audio cassette, where a sharp hissing sound is heard during pauses. Perhaps someone will consider this noise an indispensable attribute of the music of the eighties and will not want to get rid of it when digitizing rare recordings. But if you don’t find any romance in this noise, you can easily suppress it, and without harming the main composition. To do this, a filter is used that removes the signal if it drops to a certain threshold value.

Open the audio file in Sound Forge Pro and select the section of the track that you want to process. Now select Effects and Noise Gate from the program menu. Like most other tools in the application, the filter has several presets and the ability to preview the result with the selected settings.

⇡ Removing background noise in Sound Forge Pro

Sound Forge Pro's second noise reduction tool is the Noise Reduction module, which can be accessed from the Tools menu. The presence of noise usually means that the original information has been lost. The computer, when eliminating random interference, must somehow recover this data. However, by and large, this is impossible, since removing frequencies containing noise leads to the loss of the original sound and the appearance of gurgling artifacts.

When noise is random in nature, it is difficult to describe mathematically. Another thing is if this noise is caused cyclical processes, say, electromagnetic oscillations. In this case, you can predict how the waveform should be adjusted to obtain an undistorted signal at the output. To combat these "predictable" types of interference, a background noise capture technique is used. Its essence boils down to the fact that the program records a fragment of “pure” noise and then subtracts it from the audio recording. Such a fragment can be very short, lasting less than a second.

Sony Noise Reduction allows you to either automatically capture noise or do it in manual mode. In manual suppression mode, the module generates a picture of the frequency spectrum and marks control points on it that determine the nature of noise suppression. Those data on the graph that are located above the envelope will be left unchanged. And to those located below it, attenuation will be applied. Accordingly, when manually transferring control points up, the noise reduction effect will be stronger, and vice versa.

Sony Noise Reduction can use one of four noise reduction algorithms, which are called Mode 0, Mode 1, Mode 2 and Mode 3.

Default is Mode 2, which works well for most cases. But the developers recommend that you always check how the program copes with noise removal in all possible modes and choose the best result.

• Mode 0 is generally suitable for eliminating low amplitude noise. However, its use increases the likelihood of distorting artifacts;
• Mode 1 is similar to Mode 0, but is less likely to cause artifacts. On the other hand, it removes less noise;
• Mode 3 is the most gentle noise reduction mode, in which the likelihood of sound defects is minimized.

⇡ Removing clicks from audio recordings in Sound Forge Pro

Typically a musical recording translated into digital view from a vinyl record, accompanied by crackling and clicking sounds. In this case, it is not enough to use a noise profile, since the record crack is unpredictable. Sound Forge Pro has a special tool for eliminating the most common noise when digitizing audio recordings. To call it, run the command “Tools → Audio Restoration”.

In addition to selecting the noise threshold and other background noise suppression options, this tool also gives you the ability to adjust click suppression. The Click Removal Amount slider is responsible for this. By default, its value is set in the middle and is optimal for most records. Moving the slider to the right will remove more clicks, but it may also accidentally remove elements of the main audio, such as a drum sound.

⇡ Removing background noise in Audacity

To remove noise in free editor Audacity can use the same techniques as with Sound Forge. For example, the “Noise Removal” module, written by Dominic Mazzoni, in fact, one of the authors of Audacity, is suitable. To use this filter, you need to take a few seconds to create a noise profile, and then choose Effects → Noise Removal.

After this, you need to click on the “Create noise model” button and, having selected the entire audio fragment to be processed, call this filter again. Now in the settings window you can select the strength of noise reduction (Noise reduction), adjust the filter sensitivity, specify the smoothing frequency and attack time, which characterizes the filter’s reaction to the appearance of noise.

Sometimes the noise profile method does not work, or the recording is so dense that there is nowhere to get this profile from. In this case, you can resort to this trick. To obtain a profile, you simply need to make an additional recording under the same conditions in which the edited material was recorded. Next, the profile can be taken from new entry. Unfortunately, it is not always possible to recreate the initial conditions, so this technique is not suitable for all cases.

⇡ Removing a nasty squeak in Audacity

If you know the tools of sound editors well, you can eliminate interference using the sound editor tools in a comprehensive manner, and not just with one “noise reduction” filter. Suppose you are faced with another type of noise - a constant squeak at a certain frequency. This type of interference can occur, for example, due to strong interference from radio equipment. In this case, the principle of cutting out the frequency band that contains unwanted noise is used.

First of all, to do this you need to perform a frequency analysis of the track. To get such a graph in Audacity, run the command “Analysis → Build spectrum graph”.

Now carefully study the diagram - the frequency noise on the audio track will be visible as a protruding hump. Move your cursor over this area to find out the exact frequency of this peak. Remember this value. Now select the entire track and select “Effects → Nyquist Query” from the program menu.

In the window that appears, write something like this:

• (vector (notch2 (aref s 0) 6230 50) (notch2 (aref s 1) 6230 50)) for a stereo track,
• (notch2 s 6230 50) - if you have one audio track.

The number 6230 is the frequency at which interference is heard. The number 50 is a setting that you may need to experiment with to ensure that the cut frequency doesn't create too noticeable a dip in the frequency spectrum of the audio recording. You can verify that noise has been removed either by looking at the newly generated frequency spectrum or simply by ear.

⇡ Conclusion

Using high-quality equipment - expensive microphones, high-quality amplifiers, etc. - undoubtedly helps reduce noise. But in cases where it is impossible to influence the quality of the recording, it is worth remembering about digital audio processing. And even if it is not possible to completely get rid of third-party interference, in many cases the recording will become more pleasant to the ear. Therefore, if you set out to restore old recordings from a reel-to-reel or cassette recorder, be sure to try all possible options to eliminate noise, because, as you know, there is no limit to perfection.

In the first part of this lesson, we looked at the reasons for the appearance of noise in photography, its components, and what to do to avoid provoking their appearance. In this tutorial we will learn how to reduce noise in Photoshop, Capture One, Digital Photo Professional And Lightroom. All of these programs have a tool for reducing noise in photography, called in photographers' jargon " noise reduction».

At this stage it is necessary to understand that:
• If during shooting there are only two alternatives: to take a frame without noise (low sensitivity of the camera matrix) but blurred, or with noise but sharp, then I choose the second option. Because you can’t get rid of blurriness, but you can still fight noise.
• It is not always necessary to completely remove noise in a photograph; often it is enough to just reduce its level to an acceptable level.
• Luminance and chromatic noise are removed differently.
• At 100% scale of the image on the monitor, we see noise several times larger in area than it will be on a print, in a printed publication or online photo album.

This tutorial contains large photos that are automatically scaled if your screen size is smaller than necessary. When this happens, a button to zoom in to 100% will appear in the upper right corner of the photo. Only this scale will allow you to accurately assess the strength and size of noise. To view those parts of the illustration that are hidden, drag the image with the mouse over its central part. To close the photo and return to the article, press the Esc key.

Initial conditions: All noise reduction in my camera is turned off, filming is carried out in RAW format, the sensitivity is set to 3200 units (I still allow this value in my shooting) and 6400 units (let's see if I can use this sensitivity in an emergency). For control, a frame was shot at a matrix sensitivity of 100 units. Exposure compensation of +0.5 stops was made for all images. This slightly increased the noise level in the photographs, but exposure errors occur during shooting, so this correction is closer to the practical situation for the photographer. Test images were cut out ( photo 1): a) a fragment from Shnyr’s food packaging (to control text sharpness and color distortion); b) a scale with fields of different lightness (control of the strength of noise in different tones); c) a fragment of the body of the mythical creature Gava (for greater beauty). On photo 2 we see that with increasing sensitivity, noise spots grow on all target fields, which is quite natural and expected.

Photo 1: test photo.
Photo 2: increasing the sensitivity of the camera matrix leads to increased noise.
Photo 3: Reducing luminance noise reduces the sharpness of fine details in the photo.

How to remove noise in Photoshop.

Ah, pranksters, didn’t you shoot in RAW format or forgot to remove noise at the stage of converting the RAW file? Sometimes it happens. Open our photo in Photoshop, then go to the menu: Filter > Noise > Reduce Noise... (Filter > Noise > Reduce Noise...). Here is our first tested noise reduction.

Luminosity noise. It is the first two sliders (Strength and Preserve Details) that are responsible for reducing it. If we drag Strength to the right edge, we will see that the luminance noise is reduced, but the text also becomes blurrier ( photo 3). The main evil of brightness noise: fighting it leads to a decrease in the sharpness and detail of the photo. The attentive reader will notice that the Preserve Details slider is designed precisely to ensure that the image does not lose quality. Move the second slider further to the right and you'll see the sharpness and detail return. But the noise comes back with it, so it turns out that they have exchanged the flaw for soap. Settings I used for ISO 3200: Strength – 9, Preserve Details 6%. If your photo does not have small details, such as text, texture, then Preserve Details can be reduced down to 0. For ISO 6400, these settings turned out to be weak, so I increased Strength to 10, and Details was reduced to 3%, somewhat to the detriment of text sharpness ( photo 5).

Chromatic (colored) noise seems like the lesser evil. By moving the Reduce Color Noise slider to the maximum value ( photo 4) text sharpness is not reduced, color noise almost disappears, but small objects lose color saturation (look at the red and blue fields). Also note that a colored halo is formed around the red dies. Sometimes, such a change in the color of small details can be critical and impossible to photograph. Therefore, we should try to apply noise reduction to a minimum extent: for ISO 3200 I used a Reduce Color Noise value of 70%, and for ISO 6400 - 100%.

On photos 5 and 6 you see the result of the noise reduction work in Photoshop. If for ISO 3200 after noise reduction noise manifests itself at a tolerable level and there is still some reserve for greater suppression, then for ISO 6400 they are already excessive for some shooting, and I would try in every possible way to avoid using this sensor sensitivity.

Photo 4: Reducing color noise can lead to decreased color saturation of details and color ghosting.
Photo 5: reduced noise in Photoshop, ISO 3200.
Photo 6: the result of applying Photoshop noise reduction for ISO 6400.

Conclusions: Reducing luminance noise is impossible without reducing the sharpness of the photo. The use of noise reduction makes it possible to use a sensitivity of 3200 units, but a sensitivity of 6400 may not be suitable for increased requirements for photographic quality. If you take photographs for the Internet or small prints, then I can use a sensitivity of 6400 units. By reducing brightness noise in photography, we do not get rid of chromatic noise, and vice versa.

Reducing chromatic noise in photography can sometimes go unnoticed by the viewer. But if when shooting, color accuracy in small details is important, then excessive use of noise reduction settings in Photoshop is unacceptable, for example when subject photography or in food photography. The more “gentle” the noise reduction settings we use (not only in Photoshop, but in general), the better quality our image is after processing.

Digital Photo Professional

The second one for this lesson I chose Canon Digital Photo Professional(hereinafter referred to as DPP). This is a very simple RAW file converter for Canon cameras and it is with its help that I introduce students in a photography course for beginners to the capabilities of the RAW format. In order to get to the DPP noise reduction, you need to select the NR/Lens/AOL tab on the Tool Palette. Naturally, we are interested in the Noise reduction block, which contains only two sliders: Luminance... - for reducing brightness noise, and Chrominance... - for chromatic ( photo 7). As with Photoshop's noise reduction, I tried to apply the same settings in DPP to maintain a balance of quality for small details and smooth surfaces. For ISO 3200 the following parameters were used: Luminance - 7, Chrominance - 12 ( photo 8). For ISO 6400 - 12 and 20 respectively ( photo 9). The result is very similar to the one obtained in Photoshop's noise reduction.

Setting up noise reduction in DPP. I noticed that when my camera's noise reduction is turned off, DPP applies its own noise reduction to RAW files. It is not convenient to turn off photo noise reduction every time, so you need to make sure that DPP does not apply it by default. To do this, go to the DPP settings ( Ctrl keys+ K), go to the Tool palette tab, turn on the Set as defaults switch, set all sliders to 0, click OK, and restart DPP ( photo 10).

Photo 7: Canon Digital Photo Professional noise reduction.
Photo 8: the result of applying DPP noise reduction for ISO 3200.
Photo 9: the result of applying the same noise reduction for ISO 6400.
Photo 10: DPP noise reduction settings.

Capture One

Today Capture One is my main RAW file converter. As with DPP, its noise reduction ( photo 11) is not disabled, and is applied to the RAW file regardless of camera settings. Moreover, even when there is no need to reduce noise, for example, with low sensitivity. I have spent a little research algorithm of the noise reduction in Capture One, and this interested me so much that I decided to read the help of this RAW converter. Alas, I did not find any useful information on the principles of noise reduction in Capture One. Therefore, the results of my conjectures, assumptions and research will be described below.

According to the Capture One help, the noise reduction of this converter changes its settings after analyzing the file. I admit, over several years of working in Capture One, I have adjusted its noise reduction settings only a few times. Noise reduction works so gently, intelligently, unobtrusively and excellently in automatic mode that I simply forgot about its existence.

The first thing I checked was how my photography would improve when I removed the noise reduction settings for ISO 100. And nothing happened. That is, if there is no noise, then the noise reduction does not work. Then I noticed that increasing the sensitivity only changed the Color value (the effect on color noise), but not the Luminance value (brightness noise). Then I assumed that with the same Luminance value and with increasing sensitivity, luminance noise would increase in proportion to what happens in the absence of noise reduction. Not so. The noise increased, but not so significantly. I won’t guess how this happens, but I was pleased with the result of Capture One’s intelligence.

In the following experiment, I tried to find the minimum value of the noise reduction settings that would satisfy me, and compare how much softer my settings were with the default settings offered by Capture One. The changes were so minor that they can be ignored: for ISO 3200 Capture One suggested values ​​of 25 and 54 (Luminance and Color), but I found softer values ​​acceptable: 20 and 50, respectively. For ISO 6400 own installations Capture One's noise reduction completely satisfied me, and I didn't touch them (25 and 57).

There are a few more amenities that can make noise cancellation even more effective. Surface reduces large noise spots on low-contrast, smooth surfaces without affecting fine details such as text (value 70 for ISO 3200 and 90 for ISO 6400). Single Pixel allows you to remove single-pixel noise (individual knocked-out pixels) without losing fine details. True, such pixels appear only at ISO 6400 or when the matrix overheats in Live View mode. Despite the fact that the noise reduction test used a matrix sensitivity of 6400 units, I did not use this setting Capture one, since the impact of the basic tools was enough.

I'm very pleased with the quality and noise reduction capabilities of Capture One. Unlike the noise reduction devices discussed above, Capture One does not create color halos or reduce color saturation in small details of the photo. Colored noise in shadowed areas is also significantly better suppressed than previous competitors. This speaks of high quality algorithm for reducing color noise. Surface's action also makes luminance noise appear weaker, especially on plain surfaces.

You can see the results of noise reduction in Capture One at photos 12 and 13. However, it remains to test a competitor among RAW converters - noise reduction in Lightroom.

Photo 11: Capture One noise reduction.
Photo 12: the result of using Capture One noise reduction for ISO 3200.
Photo 13: the result of applying the same noise reduction for ISO 6400.

Lightroom and Adobe Camera RAW

I even downloaded the new Lightroom - 4.3... In all previous versions Lightroom, its noise reduction, according to users, was considered a weak link and was not recommended for use. Those. After converting the RAW files into Lightroom, noise reduction had to be done in Photoshop. But Photoshop’s noise reduction system is much inferior in quality to at least Capture One, and I can’t recommend this chain (Lightroom > Photoshop) for noise reduction. I have come across a mention on the forums that Lightroom noise reduction has been improved, starting with the fourth version. Wanting to clarify this information with experienced users, I again found myself on the Lightroom forums. And what I read there did not please me at all: slowdowns, difficulties in operation, glitches, in general, everything is as always with the RAW file converter from Adobe. This finally turned me away from installing Lightroom, and instead of its noise reduction, I will test a similar Photoshop tool - Adobe Camera RAW. I have long noticed that the settings of these two Adobe products are identical, and lead to the same results after processing RAW files. That is, the operating algorithms of both programs are the same (it would be strange for one manufacturer to make two versions of noise reduction). If I'm wrong and you have good reasons for this, please let me know.

In order to reduce noise in Adobe Camera RAW, you need to go to the Detail tab. This noise reduction has more settings than the noise reduction in Photoshop (photo 14). By default, for files of both sensitivities, Camera RAW suggests not reducing luminance noise, but reducing color noise (Luminance – 0, Color – 25, Color Detail – 50). At these settings, color noise is suppressed beautifully, and (as in Capture One) I don't notice any color ghosting. Wonderful. The Color Detail slider helps adjust (return) color saturation for small details (remember, this was a problem in Photoshop's noise reduction). I left the Color Detail value as default, i.e. 50. But I lowered the main Color setting to 15 (for ISO 3200) and 20 (ISO 6400).

Highlight spots on smooth surfaces remained visible but unobtrusive at Luminance settings of 55 (at ISO 3200) and 70 (ISO 6400), but did result in a slight reduction in text detail. Therefore, I chose a compromise Luminance Detail value of 40 (for ISO 3200) and 50 (ISO 6400).

I really liked how Adobe Camera RAW reduces noise ( photos 15 and 16) that I thought about the permissibility of wider use of sensitivity 6400 on my camera. If we added the Surface setting to this noise reduction as in Capture One, then it would have no equal. I wonder how the places will be distributed among the noise reduction leaders at the end of this photography lesson.

Photo 14: Adobe Camera RAW noise reduction (the settings are identical to Lightroom).
Photo 15: the result of applying Adobe Camera RAW noise reduction for ISO 3200.
Photo 16: the result of applying the same noise reduction for ISO 6400.

Noise reduction test results

Noise reduction test results in photos 17 and 18: the worst are at the top, the best are at the bottom. When shooting at high sensitivities, I do not recommend using Photoshop noise reduction for raster images and Canon Digital Photo Professional. The main reason is strong color halos around colored parts in a photograph. It is also difficult to find a compromise in these noise cancelers between the level of brightness noise on smooth surfaces and the sharpness of small details. Capture One, compared to the first two, looks in an advantageous position until the Adobe Camera RAW noise reduction comes into play. The latter showed that in many cases I could use 6400 sensitivity for commercial shooting as well: amazing luminance noise reduction for smooth surfaces while maintaining fine details and good job to reduce color noise. I don’t understand what people who work in Lightroom are complaining about?

Photo 17: Comparison table of noise reduction for ISO 3200.
Photo 18: Comparison table of noise reduction for ISO 6400.
Photo 19: Charming noise.

Conclusion

If you want to use high sensitivity values ​​when shooting, then start fighting noise at the shooting stage - shoot in RAW format. Do not transfer the process of noise reduction to Photoshop; do it in a RAW converter when correcting photos. Use the converter that will reduce noise in photography with less losses (and losses are inevitable). Use the minimum noise reduction settings.

If the photo has strong noise, then in some cases you can limit yourself to reducing only the color spots. The remaining luminance noise will be very similar to film grain. Sometimes this grain imitation is even preferable to the smooth image of a digital camera. For example, if you are stylizing a photo as antique. In other cases, grain can give a certain charm to a photo ( photo 19). It’s not for nothing that there are Photoshop filters that create similar film grain. But, this is a topic for another lesson.

PS: Not the newest noise cancelers were used in this test Adobe versions Camera RAW and Capture One. Therefore, it is possible that the noise reduction algorithms in these programs have become even more advanced.
PPS: Don't make noise!

Article content:

Introduction

Not long ago I needed to remove noise from sound. I had never done this before, so I went online to find a way to do this with minimal losses. After 10 minutes of searching, it turned out that all the paths lead to Adobe Audition.

After half an hour of experimentation, I figured out how best to remove the noise. Now I show you enough detailed instructions, how to do it. I will try to collect all the information I found together, summarize and write accessible language. I’ll make a reservation right away that there will only be instructions, and not a description of a bunch of filters for this monster (Audition). Instructions like “There is a problem - here is a solution.” And Audition is essentially the Photoshop of the audio world.

Let's say you recorded sound on a microphone, camera, phone. Often these devices do not differ in particular quality (in terms of sound recording). And there will always be noise - some kind of constant component. And if there is also a generator of additional noise (for example, the hum of coolers in a computer)... Our task is to separate it from speech or music.

There are two options here:

• The audio contains a recording of the atmosphere of a room or street without a useful signal. Those. available noise recording without impurities. For example, let's say you're going to record your friend's guitar playing using a computer microphone. The apartment is quite quiet, there are no neighbors, no one makes noise on the street either (hmm, a rather idealized situation, isn’t it), but a disgusting computer, which is a hundred years old at lunchtime, and besides, has not been cleaned of dust since the day it was born, is treacherous The coolers rattle all over Ivanovo. Well, there are two options: initially record 10-20 seconds before your friend starts playing and the same amount after finishing. In this case, you will have a clearly defined noise that can later be separated. By the way, professional journalists do this whenever possible. And the second option is to clean your computer. Moreover, the second is clearly preferable.
• There is no separate noise recording in the audio. Those. your friend started playing immediately after the recording began, and after finishing, you immediately turned off the microphone. This worst case scenario. The fact is that noise represents a collection of certain frequencies. If there is pure noise, then it is safe to say that these frequencies are noise, garbage and can be removed from the entire track. If, in parallel with the noise, there is some useful signal, then the selected frequencies will no longer be exclusively garbage. And when you remove them throughout the entire track, some part of the useful signal will be lost. Or rather, the music and voice will take on a metallic tint. Therefore, it is better to rewrite such a record. You can also try to find an area where there will be a minimum of useful signal, set less aggressive settings when cleaning noise and come to terms with the metallic echo. Or you can simply record the noise sample in separate file, unless of course you are 1000 km from this place

There is a small original file of 5 seconds in size with clearly expressed background noise. The recording was made using a smartphone voice recorder. And this noise is generated precisely by the phone and is clearly audible at a low volume of the signal source.

Noise in a photo image is an age-old problem that both novice photography enthusiasts and professionals face. Digital noise appears as individual spots of light, dark, or color that can fill entire areas in a photo. Owners mobile phones Those who shoot in low light with their gadgets are well aware of this problem. However, owners of advanced SLR cameras are often faced with the fact that contrast dots appear in photographic images, which spoil the overall impression of the pictures. In this article we will talk about how to reduce the effect of noise on photographs when shooting, as well as how to eliminate such minor image defects software.

Reducing noise in photos when shooting

It should be immediately noted that there is always noise in digital photography and this is due to the characteristics of the light-sensitive matrix, which forms the basis of any digital camera. However, in most cases the noise level is so low that the human eye is unable to discern image defects. But in some situations, especially when shooting in low light conditions, digital noise in the image becomes clearly visible. There are several ways to reduce the impact of noise when shooting:

— Do not use high sensitivity valuesISO

Perhaps the main reason for noise in photographic images is that the ISO sensitivity value set by the photographer is too high. When shooting in low light without a flash, you have to increase the sensitivity of the sensor to make the photo brighter. However, increasing the ISO value in your camera settings too much results in images becoming too noisy.

The influence of the ISO value can be assessed using the example of the photo area inside the red oval (clickable):

Noise reduction

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Although camera manufacturers are currently working hard to reduce noise levels at high ISO levels, it is still not wise to use the extended sensitivity range thoughtlessly. It is better to choose the minimum possible or average ISO value, and only after test photographs draw appropriate conclusions about the need to increase the sensitivity of the matrix. Thus, you should increase the ISO value only when there is really a need for it.

In low light conditions, try to use fast lenses or flash. As for optics, the wider the aperture is open, the shorter the shutter speed can be made. All this will allow you to take better photos in low light without the need to seriously increase the ISO sensitivity and thereby increase the risk of noise.

— Shoot from a tripod

To reduce noise, it is advisable to use a tripod or monopod on which you can mount a digital camera. This is especially true for situations where you are shooting any static objects in low light conditions. Using a tripod will allow you to set the sensitivity settings of the camera sensor to their lowest value, which, in turn, will reduce the likelihood of digital noise appearing in your photos.

— Protecting the camera from overheating

It's no secret that digital noise becomes stronger when the sensor heats up. digital camera. A simple rule applies here - the higher the temperature of the matrix, the more noise there is in the photographic image. In this regard, try not to shoot for a long time in conditions of heat, high humidity and direct sunlight, and also do not use too long shutter speeds unless absolutely necessary.

In addition, take into account the fact that when using the LiveView mode in digital SLR cameras, the light-sensitive matrix works not only during the exposure of the frame, but also a little longer, which can lead to additional heating. Therefore, you should not abuse shooting in this mode; give your camera’s sensor time to cool down.

— Shooting inRAW

It is preferable to shoot in RAW format. This format contains more information than JPEG, so you have more opportunities to get a high-quality photo. In addition, you can reduce noise in the photo image already when converting RAW files using software for image processing.

Modern digital cameras are equipped with various noise reduction functions, but the software algorithms they use are far from perfect and do not always suppress noise correctly. Often, using such a function leads to the loss of fine details of the image. In addition, if your camera has already removed some of the noise, this may complicate the subsequent processing and finishing of the photo on a computer.

How to remove noise from a photo in Photoshop

Using the capabilities of one of the graphic editors, you can safely remove digital noise from a photo. In Adobe Photoshop, this procedure is usually performed through the standard Reduce Noise filter (via the Filter - Noise - Reduce Noise menu). Before processing the image, you need to open it in Photoshop and duplicate it (Layers – Duplicatelayer). Thanks to this, at the end of the noise removal work, you can always compare the original with the processed image. After opening the Reduce Noise filter, you start working in (Basic) mode, where the following parameters will be available:

— Intensity or strength (Strength). This parameter reduces luminosity noise - the further to the right you move the slider, the more the noise will be reduced. The main thing here is not to overdo it, so that various small details do not disappear from the photo along with the digital noise.

— Save details (Preserve Details). By adjusting this slider, you can restore the missing small details of a photo image, but keep in mind that noise will also return to the photo. Here you will have to find the optimal balance between leaving the fine details of the photo and accepting the presence of a certain level of noise, and completely eliminating noise, accepting the loss of some details.

— Reduce color noise (Reduce Color Noise). This option is used to remove color spots from a photo.

— Sharpen Details. Using this option, you can try to restore the sharpness of the photo image, which naturally deteriorates with a decrease in digital noise.

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ISO 25600 - after noise reduction

Experiment with the settings, and then go to the additional mode of the same filter (Advanced). Here you can reduce noise in a single channel thanks to the “Per Channel” tab. For each channel, you can change the same above-mentioned parameters “Intensity” and “Preserve details”.

Pick up optimal settings filter for a specific photo image. If you need to get rid of the so-called brightness noise, that is, from small elements in the photo that have differences in brightness, then you can start with following settings: Intensity – 9 – 10, Detail Retention – 3 – 6%. If you are dealing with chromatic noise (the presence of colored spots in the photo), then you can set the following Reduce Color Noise value – 70 – 100%.

In conclusion, it is worth noting that the extent of the problem of digital noise in photographic images is often exaggerated by photographers themselves, who simply do not want to see any “defects” in their photographs. However, you need to remember that when viewing a picture at 100% scale on a computer monitor, you will see noise several times larger in area than in the same photograph posted, for example, in an online photo album. In addition to this, there are currently no universal noise removal algorithms. This means that noise suppression or its elimination by software one way or another leads to a partial loss of small details, deterioration in color accuracy and sharpness of the photo. Therefore, you do not need to strive to always completely remove noise from your photographic images; in most cases, simply reducing it to an acceptable level will be enough. Although if you plan to engage in commercial or stock photography, then you will have to be more strict about the technical side of the images and similar minor defects in photographic images.