The working principle of the USB camera module is mainly based on optical, electronic and image processing technology, and the following is its detailed workflow:
First, image capture
Lens: USB camera modules are typically equipped with a lens that collects light and focuses it onto the image sensor. The quality of the lens directly affects the sharpness and field of view of the image.
Image sensor: The image sensor is the core component of the USB camera module, which is responsible for converting the optical image captured by the lens into an electrical signal. At present, the mainstream image sensors are CCD(charge coupled device) and CMOS(complementary metal oxide semiconductor) two kinds. CMOS image sensors are widely used because of their low cost, low power consumption and high integration degree. The surface of the image sensor contains hundreds of thousands to millions of photodiodes, and when the photodiode is illuminated by light, it generates an electric charge, which in turn forms an electrical signal.
Second, signal conversion and processing
Analog-to-digital conversion: The electrical signal generated by the image sensor is an analog signal that needs to be converted into A digital signal by an analog-to-digital converter (A/D converter). Digital signals are more suitable for processing and transmission in computers.
Digital signal processing: The converted digital signal will be sent to the digital signal processing chip (DSP) for processing. Through a series of complex mathematical algorithms, DSP optimizes the digital image signal parameters, such as denoising, enhancing and compressing, so as to improve the image quality and transmission efficiency.
Third, data transmission
USB interface: The processed digital image signal will be transmitted to the computer or other devices through the USB interface. USB interface has the advantages of plug and play, support hot swap, vân vân., easy to connect and use.
Transmission protocol: During the data transmission process, the USB camera module follows a specific transmission protocol, such as the UVC(USB Video Class) protocol, to ensure the correct transmission of data and device compatibility.
Fourth, image display and processing
Driver: On a computer, it is usually necessary to install a camera driver to parse, process, and display the image signal transmitted by the camera. The driver can adjust, filter, enlarge and reduce the image according to the need.
Image display: The processed image signal will eventually be displayed through the display. Users can view real-time video on the computer, video calls, video surveillance and other operations.
Fifth, additional functions
In addition to the basic image capture, signal transmission, and image processing functions, USB camera modules are often equipped with additional features such as microphones, retractable stands, and shutter buttons. The microphone can achieve sound transmission during video calls, the telescopic stand can adjust the height and Angle of the camera according to needs, and the shutter button is often used for taking photos and recording videos.
To sum up, the working principle of the USB camera module is to capture optical images through the lens, use the image sensor to convert the optical image into an electrical signal, and then go through the steps of analog-to-digital conversion, digital signal processing and data transmission, and finally display and process the image on the computer or other devices.