To compress the data during image digitalizeing

storage and transmission

We always use subsample method to sample the color channels in order to cut off data rate

Then use bilinearity method to reconstruct it. How to find the best way to reconstruct the color information lead us to study the principles of subsample problem. The Nayquest law limits the signal band width to half of sample rate. In subsample condition

this point will reduce sharpness of image and cause false color on image edges. This paper is focus on the problem of image reproduction under subsample condition. On study of the features of nature image and human eyes

We found there are similarities in details of image RGB color Channels. After analyse the subsample problem

We found it's possible to rebuild the subsample image if we have the information of image grade. Take consideration of this two points

we bring forth a new way to build the CCD color image

and found this way will improve the image sharpness remarkably.