The difference of CCD and CMOS
Both CCD and CMOS use photosensitive elements to capture images. The cores of CCD and CMOS photosensitive elements are photodiodes. The diodes can produce output current when exposed to light. The intensity of the current corresponds to the intensity of the light.
CCD
The charge-clamping device is made of a high-sensitivity semiconductor material that converts light into electric charge and converts it into a digital signal through an analog-to-digital converter chip. The digital signal is compressed and stored by the camera's internal flash memory or internal hard disk card. It is easier to transfer data to a computer and use the computer's processing methods to modify the image as needed and imagined.
CMOS
Complementary metal oxide semiconductor
CMOS manufacturing technology is no different from general computer chips. It is mainly made up of semiconductors made of silicon and germanium. The current generated by these two complementary effects in CMOS can be recorded and interpreted as images by the processing chip. The shortcoming of CMOS is that it is prone to noise. Early design made CMOS overheat when it was dealing with fast-changing images.
Difference
The location and number of ADCs are the biggest differences. After the CCD exposure is finished, the electrical signal is transferred, and the charge signals of each pixel in each row are sequentially transmitted into the "buffer" of each row in sequence, and the electrical signals of each row are sequentially outputted to the bottom line by the bottom line. The amplifier next to the CCD is amplified, and then the ADC output is connected in series, which is a linear array CCD; the other is that each line has an amplifying circuit, and each line simultaneously captures the current image information of the ADC, and can simultaneously receive a complete image information. This is an area array CCD.
In the CMOS design, each pixel is directly connected to the ADC, and the electrical signal is directly amplified and converted into a digital signal.
Comparison: The characteristic of CCD is to fully maintain the signal without distortion during transmission. It can maintain the integrity of the image by collecting each pixel to a single amplifier and doing unified processing. The CMOS process is simple and has no exclusive channel design. You must first zoom in and integrate the data for each pixel. It can be seen that the CMOS imaging process is more prone to dead pixels and distortion of the image, but with the compatibility and power consumption of his process, it is more suitable for embedded needs, and at the same time, the resulting image distortion can be correspondingly The algorithm compensates, but it should be noted here that the imaging characteristics of CMOS determine that it is very susceptible to external ambient light. In the process of use, it is necessary to design a light source that meets the requirements. In essence, CCD and CMOS do not have the need to dig deeper into their content. For users, sensitivity, resolution, noise, RGB segmentation, CMYK segmentation or RGBE segmentation, etc. These indicators do not reflect the difference in use! In the course of work, there is not much difference, especially in recent years, with the continuous improvement of CMOS technology, the highest-end cameras are all CMOS.
Generally considered:
In the case of poor light, the CCD's noise control ability is indeed not as good as COMS. Under normal circumstances, we try not to use more than 400, but in good light, the purity, thickness, transparency and color of the image. CCDs are all over CMOS, as long as you adjust the curve a little, it can be very good, and more time later than COMS.