Color transformations for lossless image compression

The paper defines the conditions for the coefficients of a linear color transformation that guarantee that after one cycle of transformation and inverse transformation all further cycles of transformation do not introduce rounding errors to sample values. Moreover, the upper limits of the rounding error can be calculated according to the formulas given in the paper. The results are very important for nearly lossless compression of color images. Color transformations that decorrelate color components allow a significant increase in compression ratio achieved by use of standard lossles compression techniques applied independently to the components. The results of the paper prove that further cycles of compression and decompression together with color transformations do not increase the rounding errors. The experimental results for the RGB → YCRCB transformation are also included.