USB Camera Module Introduction

Sensor

Sensor is a device used to sense light and convert it into electronic signals. The Sensor can be divided into two different types: CMOS and CCD. Regardless of whether it is CMOS or CCD, silicon photodiodes are used to convert light to electricity, so the stronger the light, the stronger the signal. Because the working principles of CMOS and CCD are quite different, relative CMOS and CCD also have different advantages and disadvantages.

In the early days of the development of imaging technology, most high-end imaging devices (such as digital cameras, digital cameras, etc.) mostly used CCD as the main photosensitive element. In contrast, CMOS products are mostly regarded as secondary products of imaging devices. At present, a considerable number of high-end imaging devices have changed to adopt CMOS as the main photosensitive element.

CCD (Charge Couple Device)

Definition: Charge-coupled device, which is a relatively mature imaging device at present, and is a current signal in units of rows. The surface of the photosensitive element on the CCD has the ability to store charge and is arranged in a matrix. When light is felt on the surface, the charge will be reflected on the element, and the signals generated by all the light-sensing components on the entire CCD constitute a completed picture.

CMOS (Complementary Metal-Oxide Semiconductor)

Definition: Complementary metal-oxide semiconductor. It is regarded as the imaging device of the future, because the CMOS structure is relatively simple and the same as the existing large-scale integrated circuit production process, so the production cost can be reduced. In principle, the CMOS signal is a charge signal in units of dots, which is more sensitive, faster, and saves power. The current advanced CMOS is not worse than the general CCD, but the CMOS process is not very mature. The ordinary CMOS has low resolution and poor imaging, and it is too prone to noise points.

Generally speaking, the image quality of CCD sensors is better than that of CMOS sensors. However, recently, CMOS has been comparable to CCD in low-brightness performance. In high-brightness applications, system product designers still prefer to use CCD sensors. Facing future mainstream applications, if you want to capture high-quality images in a low-brightness environment, or apply to the image input requirements of light, thin and short personal mobile products, the advantages of CMOS sensors are unmatched by CCD sensors.

DSP

The function of DSP is mainly to receive the data transmitted by the Sensor. When the Sensor receives the light source data, it will output the data, and then it will be received by the DSP, and then the DSP will exchange this signal into a USB signal and send it to the computer.
Quite a lot of sensors have ISP (Image Signal Processor). Such sensors can process images by themselves, so the data sent to DSP are all processed images. DSP only needs to convert the sensor’s YUV signal into Just use USB, or compress the image and convert it to Motion JPEG compression format.