Webcam - technical specifications, how to choose, rules of use. Web camera for surveillance Description and technical characteristics of the web camera

The digital webcam is network device, which consists of a video camera (CCD matrix), a compression processor and a built-in web server. As a rule, a webcam is used as a device for organizing video recording, video conferencing or video surveillance and transmitting video images over a LAN/WAN/Internet network. To operate a webcam on a network, no special devices or a personal computer are required. Depending on the settings, access to the video image received by the webcam can be open to all network users or only authorized users.

The design and principle of operation of a webcam

A modern webcam is digital device, producing video recording, converting an analog video signal into a digital one, compressing a digital video signal and transmitting video images over a computer network. Therefore, the webcam includes the following components:

CCD matrix,

lens,

optical filter,

video capture card,

video compression unit,

central processor and built-in web server,

flash memory,

network interface,

serial ports,

alarm inputs/outputs.

It is used as a photodetector in most web cameras. CCD matrix ( CCD, CCD - charge-coupled device) is a rectangular photosensitive semiconductor plate with an aspect ratio of 3: 4, which converts the light incident on it into an electrical signal. The CCD matrix consists of a large number of photosensitive cells. In order to increase the light sensitivity of a CCD matrix, a structure is often formed that creates a microlens in front of each of the cells. The technical parameters of a webcam usually indicate the format of the CCD matrix (diagonal length of the matrix in inches), the number of effective pixels, scan type (interlaced or interlaced) and sensitivity.

Lens is a lens system designed to project an image of an observation object onto the light-sensitive element of a web camera. The lens is an integral part of the webcam, so the quality of the video image received by the webcam depends on its correct selection and installation. Quite often, a webcam comes with a lens. Lenses are characterized by a number of important parameters, such as focal length, relative aperture (F), depth of field, type of mount (C, CS), format.

Optical infrared cut filters , which are installed in webcams, are optically precise plane-parallel plates mounted on top of the CCD matrix. They operate as optical low-pass filters with a cutoff frequency of about 700 nm, near red. They cut off the infrared component of light waves, providing the webcam with correct color reproduction. However, many black-and-white webcams do not have such filters installed, which is why monochrome webcams have higher sensitivity.

Video capture card The web camera (digitization unit) converts the analog electrical signal generated by the CCD matrix into a digital format. The signal conversion process consists of three stages:

Sampling,

Quantization

Coding.

Sampling- reading the amplitude of the electrical signal at regular intervals (period). This stage of signal conversion is characterized by the sampling frequency.

Quantization is the process of presenting sampling results in digital form. The change in the level of the electrical signal over the sampling period is represented as a code word of 8, 10 or 12 bits, which give 256, 1024 and 4096 quantization levels, respectively. The accuracy of the signal representation in digital form depends on the number of quantization levels.

Coding. In addition to the information about changes in signal level obtained at the previous stage, the encoding process generates bits indicating the end of the clock pulse and the beginning of a new frame, as well as additional error protection bits.

Compression block webcams compress the digitized video signal into one of the compression formats (JPEG, MJPEG, MPEG-1/2/4, Wavelet). Thanks to compression, the size of the video frame is reduced. This is necessary for storing and transmitting video over the network. If the local network to which the webcam is connected has limited bandwidth, then in order to avoid overflowing the network traffic, it is advisable to reduce the amount of transmitted information by reducing either the frequency of frame transmission over the network or the frame resolution. Most compression formats that webcams use provide a reasonable compromise between these two ways of solving the problem of transmitting video over a network. Compression formats known today make it possible to obtain a digitized stream with a bandwidth of 64 KB - 2 MB (with this bandwidth, video data streams can work in parallel with other data streams in networks).

Video compression in a webcam can be done either in hardware or in software. Software implementation compression is cheaper, but due to the high computational capacity of compression algorithms, it is ineffective, especially when you need to view video from a webcam online. Therefore, most leading manufacturers produce webcams with hardware compression. For example, each AXIS Communications network camera is equipped with an ARTPEC compression processor, which performs high-speed video compression into the JPEG/MJPEG format.

CPU is computing core webcams. It carries out operations for outputting digitized and compressed video images, and is also responsible for performing the functions of a built-in web server and a control program for web cameras.

Interface for Ethernet serves to connect the webcam to a 10/100 Mbit/s Ethernet network.

To work on the network, the webcam can have serial port for connecting a modem and working in dial-up mode in the absence of a local network. You can also connect peripheral equipment to the webcam through the serial port.

Flash memory card allows you to update webcam control programs and store custom HTML pages.

RAM serves to store temporary data that is generated during the execution of control programs and user scripts. Many Internet cameras have a so-called video buffer. This is a part of RAM reserved for recording and temporary storage of video frames captured by the webcam. The information in the video buffer is updated cyclically, i.e. the new frame is recorded instead of the oldest one. This function is necessary if the webcam performs security video surveillance, since it allows you to restore events preceding and following the alarm from security sensors connected to the webcam.

Alarm inputs/outputs are used to connect alarm sensors to the webcam. When one of the sensors is triggered, an alarm signal is generated, as a result of which the webcam processor composes a set of frames recorded in the video buffer before, after and at the time of the alarm. This set of frames can be sent to a given e-mail address or via FTP.

Connecting and installing a webcam

Typically, the webcam is connected to Internet networks via 10BaseT/100BaseTX/1000BaseTX Ethernet port or using a modem via serial port. Once the webcam is physically connected to the network, it is assigned an IP address. Most often, the webcam does not have a default IP address; it is installed either using the appropriate function of a standard web browser, or by a DOS command that uses for identification serial number webcam, assigned to it by the manufacturer. In addition, manufacturing companies are developing special programs for webcams, which greatly simplify the procedure for assigning an IP address to a webcam (for example, IP Installer from AXIS Communications). Thanks to the built-in software for a web server, FTP server, FTP client, e-mail client, etc., the webcam connects directly to the LAN/WAN/Internet network and works in it as an independent network device. This makes webcams different from others digital cameras, which require mandatory connection to personal computer via USB or LPT port. In addition, webcams can support working with user scripts and JAVA applets.

To install a webcam outdoors or indoors, many manufacturers include special fasteners in the design of the camera body designed for installation on walls, ceilings, brackets and rotating devices. Some webcams have built-in rotating devices designed to be mounted on a horizontal or vertical surface.

Additional features and functions of the webcam

Motion Detector is a software module whose main task is to detect web cameras moving in the field of view at a video surveillance site. The motion detector not only detects movement in the image field, but also determines the dimensions of the object and the speed of its movement. Depending on the video surveillance tasks, the webcam motion detector is configured to detect the movement of objects with the utmost minimization of false alarms (interference filtering), and flexible alarm processing logic is set (alarm recording, integration with other security equipment).

Audio transmission over the network in most cases is carried out by connecting an additional audio module to the webcam. For example, AXIS Communications to expand functionality webcams produces a special audio module AXIS 2191, compatible with most AXIS webcams.

Password protection serves to restrict access to the webcam by persons who do not have access rights.

By default, the video image from the webcam can be viewed from any network computer that has a standard web browser installed, for example, Internet Explorer or Netscape Navigator. However, you can limit the number of people who have access to the webcam by entering a user-level password. Many webcams support multi-level password protection to differentiate access and administration rights.

Webcam programs

Typically, the webcam image can be viewed using a standard web browser, such as Internet Explorer or Netscape Navigator. However, many manufacturing companies develop exclusive programs for webcams.

They combine the functions of a web browser and management software to manage, configure and view webcam images (eg AXIS Camera Explorer or JVC Professional's V.networks network device management software). There is also software for distributed network video surveillance systems that supports equipment from various manufacturers, such as Sphinx-DV from Digicore Systems.

Connecting the webcam to the network

Currently, a webcam can connect to the network in several ways, which are based on different data transfer standards.

10/100 MbitEthernet. This is the most popular way transferring data from the webcam to the network. There are two standards for 10 Mbit Ethernet networks: 10Base2 (using coaxial cable) and 10BaseT (using twisted pair). 10Base2 is used extremely rarely due to the sensitivity of coaxial cable to external noise. The 100BaseTX standard uses twisted pair and provides a data transfer rate of 100 Mbit/s.

1000 Mbit Ethernet, Gigabit Ethernet. The 1000BaseTX standard used here is an improved version of 100BaseTX. This standard is used mainly for building local network backbones.

Standard telephone modems. This is a cheap and fairly common way to connect a webcam to global network. The main disadvantage of this connection method is low speed data transfer (maximum data download speed - 56 kbit/s, maximum upload speed - 33.6 kbit/s). The webcam is connected to the modem via a serial port.

ISDN modems. The ISDN (Integrated services Digital Network) standard is used to transmit digitized graphics, audio and video information and other digital data over private or public digital networks. telephone networks. The ISDN standard provides data transmission from a web camera at speeds of up to 128 kbit/s over two channels.

xDSL modems. DSL (Digital Subscriber Line) is a technology that provides wide bandwidth over simple copper telephone wires. The webcam data transfer speed may vary depending on the company providing the service. On average, it is 1 Mbit/s for downloading data and 250 kbit/s for uploading.

Cable modems. A cable modem is a modem that provides access to the Internet over networks cable television. Cable modems use asymmetric technology, which is best suited for user access to the Internet. At the same time, the maximum possible speed of receiving data from a webcam with such a modem can reach about 40 Mbit/s (although it usually does not exceed 1 Mbit/s), and the data transmission speed is about 10 Mbit/s.

Cellular modems. Using a cellular modem, you can connect your webcam to the Internet using cellular communication lines. Data transfer rates are typically between 5 and 20 kbps.

More detailed Technical information for specific models of web cameras from Axis Communications and JVC Professional are presented on the same website in the video cameras section. Brief technical specifications and prices for webcams are given in the ARMO-Systems online store.

How to access a webcam over the Internet

How to access a webcam over the Internet.

Example: After you already receive the image from the webcam on your computer, you decide that it would be nice to be able to access the camera wherever there is Internet. For example, as a store owner, you want to control the activities in the store from your home, instead of having to be present every minute at the workplace

Step 1: System Requirements

Scenario A)

If your building (where the camera should be located) is already connected via Ethernet to an ISP (internet service provider), simply configure account, connect the network camera to the switch via the network output, and you should get a dynamically assigned public IP address for the network camera. Follow the installation commands for the network camera. Special software or utility for the webcam will be useful in identifying the IP address.

Since the assigned IP address may be changed by your ISP (due to the limited supply of IP addresses shared among its clients), see Step 4 below to find out how you can assign cameras to a specific IP address.

Scenario B)

If your building is not equipped with Ethernet access, then in most cases you may need the following devices:

broadband modem for connecting an asymmetrical digital subscriber line (usually supplied by your Internet service provider) or cable television

broadband router, which can also be called an Internet Gateway, (A broadband router allows local network users to share a single Internet connection. It also serves as an interface between the Internet, the ISP and the Local Network)

switch that allows various devices from the network communicate directly with each other and allows devices from the local network to have separate IP addresses),

NOTE: Most broadband routers have a built-in switch function, so no separate hardware is required.

network camera

local computer

computer for remote monitoring

Step 2: Assign an IP address to your camera

Since a broadband router typically assigns automatic, local IP addresses to devices on the local network, such IP addresses are subject to change. A static (permanent) IP address is recommended for the network camera. To assign a static IP address, find out the router's IP address range, which, for example, could be from 192.168.0.2 to 192.168.0.35. If you choose to use an out-of-range IP address, such as 192.168.0.100, as a static IP address for the camera, it is likely that you will not risk your device conflicting with other devices that receive automatic addresses.

Setting the IP address for your camera can be done in three different ways, as indicated in the camera manual. Once the IP address is assigned, set the subnet, and gateway (this information can be obtained from the router), and configure the camera settings: password, registered users to ensure access restrictions to the camera.

Step 3: Port Forwarding

The broadband router, as mentioned earlier, provides the interface between the Internet, the ISP and the Local Network. The router obtains an external IP address from the Internet service provider and supplies internal (local) IP addresses to devices on the local network.

To access a network camera that resides on a local network, you must identify the external IP address of your router (see your router's manual), and configure your router so that the external IP address is directed to the static, local IP address of the network camera . This process is called opening a port; that is, when you type the router's external IP address from any network computer, the Internet locates your router, in turn forwarding your request to the local IP address that is assigned to the network camera.

Launch your Web browser and log into the router's built-in Web pages through Login to Router Configuration Pages.

Find the menu item "port forwarding" (or similar), with a table approximately as shown below:

Service name	Start port	End port	Server IP address
			Not configured
			Not configured
			Not configured

Since the camera sends its video over HTTP, you must configure the HTTP service like this:

Service name	Start port	End port	Server IP address
			Not configured
Unofficial port

Save the configuration to the router and exit the configuration pages. The configuration is complete. Any requests reaching the router's external IP address on port 80 will now be sent to the camera's IP address: 192.168.0.100.

If you want to make more than one network camera accessible via the Internet, then you must use additional (unofficial) router ports, such as 80xx, and associate them with the network address of the IP camera.

Step 4: What can you do if your ISP frequently changes Dfi external IP address

Create an account in the DNS service that serves and registers domain names(for example www.nic.ru, etc.) and bind it to an external IP address. A domain name, such as www.web-kamera.ru, is clear to the user, easy to remember, and you can assign each domain its own network device, i.e. its IP address. Whenever the router's IP address changes, it will be automatically registered by the DNS service to update your IP address so that you can access your network camera using the same address.

Most broadband routers have native DNS support, such as www.dyndns.org.

Another alternative: You can buy or rent a static external IP address from your Internet service provider.

A professional webcam is a digital video or photo camera that allows you to scan the image around the webcam in real time and transmit this image over the Internet. To transfer images over the Internet, use the Instant Messenger program or another program that allows you to play back the image transmitted to the camcorder.

What does a webcam consist of?

Any web camera consists of a video camera (CCD matrix), a special compression processor, and a built-in web server. Today, there are two types of matrices: CCD matrices and CMOS matrices. Such matrices differ in the degree of detail and image clarity. During operation, the web camera shoots video and converts analog signal V digital signal. The converted digital signal is processed by a special video capture card. After this, the video image can be transmitted over the Internet.

Structurally, the video camera includes: a CCD matrix, an optical filter and a lens, a special computer video capture card, a video compression unit, RAM and a central processor, flash memory and a network interface, ports for connecting to various devices.

The CCD matrix is ​​a light-sensitive conductor. A conductor is a plate that converts light into an electrical impulse. The CCD matrix includes a significant number of photosensitive cells. That is why the sensitivity of the CCD matrix directly depends on the number of effective pixels.

insides of a webcam with and without lens

A web camera lens is used to project an image of an object onto a computer's CCD matrix. The quality of the image formed largely depends on the quality of the lens. Some of the key characteristics of the lens are: focal length, depth of field of the lens, format and other technical characteristics of the web camera.

Optical filters of a web camera have the form of flat parallel plates. Such plates are located on top of the matrix and are designed for high-quality color rendering of the web camera.

The web camera video capture card converts the analog electrical signal into digital format.

The web camera compression unit compresses video signals. By reducing its volume, it converts video signals into compression formats such as JPEG, MJPEG, MPEG - 1/2/4 or Wavelet. Video signal compression allows you to significantly reduce the amount of video information for easy storage and transportation of video images over the Internet. There are hardware and software video compression. Most webcams are released with hardware compression, as this is the fastest compression method.

With the help of the central processor, tasks of reproducing compressed and digitized video images are carried out. Interface – Ethernet is responsible for connecting the webcam to the local network. In the presence of USB port(more common type) the camera can be connected directly to the computer input.

Optionally, the webcam may contain web server software. Then it becomes a completely autonomous service, the connection to which can be made directly by users via the Internet. In the usual case, the camera is used as a generator of a video stream, which is processed by a computer and transmitted to the network using software installed on it.

Advantages and disadvantages of a web camera

The main advantage of a web camera is its mobility and the ability to transmit video information online. The disadvantage of a web camera is that it is quite low quality images and the mandatory presence of a broadband Internet connection to transmit images online. For normal image recording, broadband Internet access is not required.

How does a webcam work?

After connecting the webcam to the Internet, it is assigned a web address. There are also special programs that automatically assign an address to a web camera. When a web camera is detected by a computer, it begins to work as a network device, converting the image entering the lens into a digital signal for recording or transmission to the Internet. This is how the web camera works.

Typically needed in four cases: for work video conferences, video calls to family and friends, as well as for streaming and recording video blogs. Depending on the purpose of your camera, you need to choose a specific model - for conversations with loved ones, a not very advanced camera is enough, but for recording videos for your blog, higher-level cameras are recommended.

As is the case with many others electronic devices, a webcam can be purchased for a couple of tens of dollars or several hundred - it all depends on your wishes and budget.

In the next section we will talk about the most important characteristics webcams, then we'll give you a few useful tips, and then we will present to your attention ten interesting models that can be found and purchased in our catalog.

Key Features You Should Pay Attention to

Sensor resolution, MP

Characterizes the number of photosensitive elements of the camera matrix that capture light during the process of taking video or photos. The higher the resolution, the better. To record HD video, models with a 1-megapixel sensor are sufficient; for FullHD, a 2-megapixel model is required. In most cases more a high resolution no need.

Video resolution, pixels

Even the cheapest modern webcams can record video in FullHD resolution. Their main difference is the maximum frame rate and the quality of the video itself. Before bribery specific model be sure to check out the examples of videos that were shot with its help - they are easy to find on YouTube.

Photo resolution, pixels

In general, webcams are not designed for taking photos - except for social networks. But no one bothers you to take a few pictures with them if you don’t have another device with a camera at hand. The quality will most likely be mediocre at most - even top webcams use interpolation to increase the resolution of images.

Frame rate per second

Not all models can record FullHD video at a frequency of 30 frames per second - usually only expensive cameras can do this. But in many cases this is not necessary - it is unlikely that the smooth movements of your face are important for video conferencing and communication with friends. But if you are choosing a camera for streaming or blogging, then a high frequency is extremely necessary - on a full-size video, less than 30 frames per second looks disgusting.

It is worth noting that manufacturers often lie about the maximum frame rate of the video their cameras shoot - cheap models are characterized by characteristic “brakes” and jerks in the stream.

Focusing

The presence of an automatic focusing system in the camera significantly improves the final image quality and allows the user to move freely in the frame without losing focus.

Manual focusing allows you to fine-tune the focus of the lens for specific conditions - for example, making video calls from a chair in front of the monitor.

The cheapest cameras do without focusing systems at all and have a fixed focus.

Viewing and rotation angles

A very important parameter of a webcam is the viewing angle of its lens, which determines the amount of space that fits into the frame. It is best to choose a model with a viewing angle of 70 degrees or more.

For a comfortable installation of the camera, the ability to rotate it, both horizontally and vertically, is also important. Many models can rotate 360 ​​degrees horizontally, but this is not needed too often - generally 180 degrees is enough.

Connection

The vast majority of modern webcams are connected to a PC using USB ports (USB 2.0). Very few models use Bluetooth or Wi-Fi - it's simply not necessary when the user usually has a smartphone with an equally, if not more capable camera at hand.

Microphone

Almost all webcams you can buy now have a built-in microphone. Most of these microphones, however, do a rather poor job of recording sound - if you plan to vlog or stream, it is better to use a microphone on the headset or a separate microphone. However, expensive webcams handle audio quite well - again, examples of audio recording from them can be found on YouTube.

For almost every webcam model, you can find an example of video and audio recording on YouTube. If you are satisfied with the quality of the video found, pay attention to the conditions of its shooting, in particular the lighting. As long as the quality doesn't suffer too much in the dark, the camera is worth considering.

Be sure to make sure that the camera connection cable will reach the USB port of your PC. Monitors with USB ports are very convenient in this regard - the camera in most cases is located either on the monitor or next to it.

On the bottom of many good cameras For professionals there is a thread for mounting on a tripod. If you are going to use it, check for the presence of such threads.

If you are going to use software from a camera manufacturer, read reviews about it online. Very often this software is old, unfinished and simply buggy.

A modern webcam is a digital device that records video, converts an analog video signal into a digital one, compresses a digital video signal and transmits video images over a computer network. Therefore, the webcam includes the following components:

• CCD matrix,
• lens,
• optical filter,
• video capture card,
• video compression unit,
• central processor and built-in web server,
• flash memory,
• network interface
• serial ports,
• alarm inputs/outputs.

It is used as a photodetector in most web cameras. CCD matrix (CCD, CCD - charge-coupled device) - a rectangular photosensitive semiconductor plate with an aspect ratio of 3: 4, which converts the light incident on it into an electrical signal. The CCD matrix consists of a large number of photosensitive cells. In order to increase the light sensitivity of a CCD matrix, a structure is often formed that creates a microlens in front of each of the cells. The technical parameters of a webcam usually indicate the format of the CCD matrix (diagonal length of the matrix in inches), the number of effective pixels, scan type (interlaced or interlaced) and sensitivity.

Lens is a lens system designed to project an image of an observation object onto the light-sensitive element of a web camera. The lens is an integral part of the webcam, so the quality of the video image received by the webcam depends on its correct selection and installation. Quite often, a webcam comes with a lens. Lenses are characterized by a number of important parameters, such as focal length, relative aperture (F), depth of field, type of mount (C, CS), format.

Optical infrared cut filters, which are installed in webcams, are optically precise plane-parallel plates mounted on top of the CCD matrix. They operate as optical low-pass filters with a cutoff frequency of about 700 nm, near red. They cut off the infrared component of light waves, providing the webcam with correct color reproduction. However, many black-and-white webcams do not have such filters installed, which is why monochrome webcams have higher sensitivity.

Video capture card The web camera (digitization unit) converts the analog electrical signal generated by the CCD matrix into a digital format. The signal conversion process consists of three stages:

• Sampling,
• Quantization
• Coding.

Sampling– reading the amplitude of the electrical signal at regular intervals (period). This stage of signal conversion is characterized by the sampling frequency.

Quantization is the process of presenting sampling results in digital form. The change in the level of the electrical signal over the sampling period is represented as a code word of 8, 10 or 12 bits, which give 256, 1024 and 4096 quantization levels, respectively. The accuracy of the signal representation in digital form depends on the number of quantization levels.

Coding. In addition to the information about changes in signal level obtained at the previous stage, the encoding process generates bits indicating the end of the clock pulse and the beginning of a new frame, as well as additional error protection bits.

Compression block webcams compress the digitized video signal into one of the compression formats (JPEG, MJPEG, MPEG-1/2/4, Wavelet). Thanks to compression, the size of the video frame is reduced. This is necessary for storing and transmitting video over the network.

CPU is the computing core of the webcam. It carries out operations for outputting digitized and compressed video images, and is also responsible for performing the functions of a built-in web server and a control program for web cameras.

Interface for Ethernet serves to connect the webcam to a 10/100 Mbit/s Ethernet network.

To work on the network, the webcam can have serial port for connecting a modem and working in dial-up mode in the absence of a local network. You can also connect peripheral equipment to the webcam through the serial port.

Flash memory card allows you to update webcam control programs and store custom HTML pages.

RAM serves to store temporary data that is generated during the execution of control programs and user scripts. Many Internet cameras have a so-called video buffer. This is a part of RAM reserved for recording and temporary storage of video frames captured by the webcam.

Alarm inputs/outputs are used to connect alarm sensors to the webcam. When one of the sensors is triggered, an alarm signal is generated, as a result of which the webcam processor composes a set of frames recorded in the video buffer before, after and at the time of the alarm. This set of frames can be sent to a specified e-mail address or via FTP.

Web cameras, their purpose and application features have been discussed many times in our magazine. The last review article - “Web cameras in World Wide Web networks” by Yu. Semko - was published in No. 2’2002. However, since then there have been major changes in this market.

Firstly, the high-speed USB 2.0 interface has become widespread, which has made it possible to increase the image transfer speed and increase its format. Indeed, even despite the fact that the main purpose of Web cameras is the communications market (transmission of video information over low-speed communication channels, for example using a modem), which dictates strict restrictions on the flow of information, and therefore on the format and degree of compression of the image, from a higher quality using the source material always produces a more acceptable result.

Secondly, the rapid development wireless technologies served as the impetus for the creation of a whole family of wireless Web cameras. From latest news, appeared on sale, it can be noted wireless bluetooth Logitech QuickCam Cordless webcam (http://www.logitech.com/). It is equipped with a CMOS sensor (like all other Web cameras), but its resolution is slightly higher than usual (510S492). As an alternative connection, the USB 2.0 interface can be used. Of course, wireless cameras are still quite expensive - the Logitech QuickCam Cordless price is more than $200, that is, almost 10 times more expensive than the cheapest Web cameras, the image from which is transmitted over a wire.

Thirdly, last year it appeared a large number of new manufacturers of Web cameras and the range of models, shapes and types of devices has expanded significantly. Logitech and Intel are still considered the recognized leaders in the production of Web cameras, followed by such well-known companies as Genius, Creative, Philips, Kodak, etc.

Fourthly, a large number of combined devices have appeared with the functions of a camera, video camera and portable tape recorder, as well as a Web camera with the ability battery life in camera and video camera modes.

And the last thing to note is the final transformation of the Web camera from a fun toy into a fully functional and useful tool.

Equipment of modern web cameras

Many modern Web cameras have similar functional characteristics and differ only in design and software included in delivery.

For example, a typical Genius WebCAM Live web camera includes:

• cable for connecting to the USB interface;
• remote microphone with a clip for attaching to clothing;
• table stand;
• set of batteries for offline operation.

In addition to the drivers, the CD contains the following additional software:

• ArcSoft PhotoImpression is a photo editing program. It contains many tools, as well as useful and fun photo templates;
• ArcSoft VideoImpression is easy-to-use video editing software;
• ArcSoft PhotoBase is a cataloger of multimedia files. With its help you can create albums of graphic, video, sound and other files;
• ArcSoft FunHouse is a fun program for editing and editing images.

The software package for Creative cameras includes applications for circular panning and interactive video recording, a WebCam utility with a program for recording motion, Creative's Oozic Player program for visualizing music, and a suite of Ulead programs for editing photo and video information.

Other Web cameras are equipped in a similar way. A set of software allows you to immediately start working fully with the camera and get results immediately.

A fairly common method of application is a scanner

If you do not have access to the Internet, then a Web camera can still be useful to you. With its help, you can quickly “scan” a picture or text, and the text can even be subsequently “recognized” and saved in alphanumeric form. You just need to select a flat surface, illuminate the object well and click on the corresponding button in the simple program supplied with the camera. This method of “scanning” is especially relevant for large format objects that cannot be easily flatbed scanner Can't put it down.

A very common way to communicate

If you have access to the Internet, then running Windows 98/Me/2000/XP you can use standard programs such as Windows Messenger or NetMeeting and communicate with your interlocutor on the other side of the world, seeing his image (sometimes, however, with a large delay). If the communication speed is very bad, then you can automatically take photographs of your interlocutors at predetermined intervals, after which the image will be automatically sent to and received from the person with whom you are communicating. Even with our communication speeds and more or less modest image resolution, it is possible to ensure that your interlocutor receives at least 5-10 fresh photos per minute.

In a similar way, you can organize a video conference with a group of remote people (although you may need special software in this case).

Spy and/or security method - surveillance systems

It is this option that has become most widespread and has even become associated with the very concept of “Web camera”. With this method of use, a video sequence or individual images from the camera are either sent to you at a predetermined address, or saved on a medium, or simply published on a Web page with automatic updates at regular intervals. There are even cameras that can respond to movement (however, a motion sensor can be implemented in software on a computer and made to record only the changing image from the camera).

In principle, security and video surveillance systems are serious and expensive products with special software, but some semblance of such a system can be assembled independently. Moreover, the system will not only save pictures at certain intervals in the archive on the hard drive, but will do this only when the motion sensor notices a disorder in the protected area.

Currently, the direction is rapidly developing digital systems video surveillance (many of them are based on a regular computer), which, according to all forecasts, will soon replace analog ones. Digital video surveillance systems, compared to analog ones, have many advantages:

• information is recorded on digital media (HDD, CD-RW, etc.), and on regular HDD costing about $100, you can record video information compressed with acceptable quality, recorded for almost a month, and the capacity/cost ratio of the media is constantly increasing (2-3 times per year). Records on disks can be equipped with a convenient search system, and there is no problem of rewinding the media;
• high speed modern processors allows you to implement devices such as a motion detector, programmatically, thanks to which the digital video surveillance system has many useful functions (for example, a reaction to a certain triggering of a sensor, motion detector, etc.); if desired, you can even change the logic of the system’s behavior;
• the system is easily integrated into modern digital networks or the Internet, which allows you to view certain cameras on different remote computers;
• and finally, the processing of video information is greatly simplified - for example, processing a still frame in order to improve the quality of the image (the face of an attacker, etc.) and sequentially printing it on a standard printer.

Currently, there are a large number of professional digital video surveillance systems that solve different problems and, accordingly, have different capabilities and prices, but a fully functional system can be implemented on cheap Web cameras with USB interface(especially since today the number of USB connectors on motherboards reaches 6-8). For example, the program included with Creative's WebCam allows you to turn your computer into a simple security system that starts capturing images when it detects any changes in the frame (motion sensitivity can be easily adjusted). You can set the camera so that the computer sends sound signal when an object moves in the frame. Alarm signal and image can be in automatic mode transmit by e-mail or stream the video to a website.