How to setup webcam

Photosensitive sensor - is a kind of heart of any digital camera. It is that sensor that provides the conversion of light into electrical signals that are available for further electronic processing. The basic principle of action and CCD and CMOS sensors are similar: under the influence of light in semiconductor materials born carriers charge, which later transformed into voltage. The difference between CCD and CMOS sensors is primarily a way of stockpiling and transfer of charge, as well as in the technology conversion to analog voltage. Without going into details the construction of various types of sensors, mention only that CMOS sensors are considerably cheaper in the production, but also more "noisy".

The principle of the webcam is similar to the principle of work of any digital camera or the camera. In addition to the optical lens and light CCD or CMOS sensor is an obligatory analog-digital converter (ADC), whose main purpose - to convert analog signals of light sensor, which is stress in the digital code. Another important element of the camera scheme is responsible for data compression and preparation for transfer in the right format. In Web-cells data is transmitted to the computer for USB-interface, so the final circuit of cameras should be USB-controller interface.

Taking into consideration the low bandwidth of USB-bus (a total is about 12 Mbps, of which webcam uses no more than 8 Mbps), the data is needed to be compressed before the immediate transfer to the computer. Evidence of this can be seen from a simple calculation. When solving frame 320 × 240 pixels and 24-bit color depth shot size in uncompressed form will be 1.76 Mbit. With the width of bandwidth USB-Channel 8 Mbps in uncompressed form, you can transfer images at speeds of no more than 4.5 frames per second. However, to obtain high-quality video transmission speed it is necessary to have 24 or more frames per second. Thus, it becomes clear that without hardware compression transmitted information functioning camera would have been impossible. Therefore, any controller chamber must provide the necessary data compression for transmission on their USB-interface. Actually compression - this is the basic purpose of USB-controller. By providing the necessary compression in real time, the controller usually makes it possible to transmit video at speeds of 10-15 frames per second in the settlement of 640 × 480 and at a speed of 30 frames per second in the settlement of 320 × 240 and smaller.