Suppose now that lossy compression is applied to , obtaining a compressed image . Then, in simulations, it becomes possible to calculate a metric Metr for either a pair of images and , (denote it as ) or a pair of images and , (denote this metric as ). Any conventional metric worsens for any coder for larger CR. This deals with the fact that more distortions are introduced in compressed data if the CR increases. Note that usually dependences of on CR [or another parameter that controls compression (PCC) as bpp or quantization step (QS) or scaling factor (SF)] are considered for conventional analysis of lossy compression performance.