The function of ISP is complicated, which is basically related to the image effect. It contains several image algorithm processing modules, among which the typical ones are: dark current subtraction (removing bottom current noise), linearization (solving data nonlinearity), shading (solving brightness attenuation and color change caused by lens), removing bad points (removing bad point data in sensor) and denoising (removing noise).
The work of ISP chip
It is to calculate and process the signal input by the sensor, and finally get the result after linear correction, denoising, bad point repair, color interpolation, white balance correction, exposure correction and so on. ISP chip can largely determine the final image quality of mobile phone camera. Generally, it can improve the image quality of 10%- 15%, and more depends on CMOS.
Although the image signal processing unit can post-process the sample quality, there are obvious differences in shooting performance between different chips or different products using the same chip, because ISP not only has processing ability, but also has programmability, and the new algorithm debugged in different ways will widen the gap with the original integrated algorithm.