imgdpcmdecode [-p predictor] imagewidth imageheight quantizers... channels... imgfile
imgdpcmencode encodes an image using two-dimensional DPCM. DPCM encoding is accomplished by calling QccIMGImageDPCMEncode(3) ; essentially, DPCM is applied to each image component (Y, U, V) separately. A separate channel file (CHN format) is output for each component.
imgdpcmdecode performs decoding of channels produced by imgdpcmencode(1) , outputting the reconstructed image to imgfile. imgdpcmdecode can produce grayscale (PGM) or color (PPM) images. In the case of color images, DPCM decoding is applied to each image component (Y, U, V) separately.
For color images, imgdpcmencode and imgdpcmdecode expect to be given three scalar quantizers, one for each of the Y, U, and V components, respectively, of the image. Additionally, channel indices are written to or read from three separate channel files (channels). For grayscale images, only one quantizer and one channel need be specified.
The -p option specifies the predictor code to be used. See QccIMGImageDPCMEncode(3) for valid values.
A. K. Jain, Fundamentals of Digital Image Processing. Englewood Cliffs, NJ: Prentice Hall, 1989, pp. 483-498.