Image Processing Reference
measure the lineal correlation between the original α ( ν , r ) applied during the F-pSQ process
and the recovered . Table 2 shows that there is a high similarity between the applied
VFW and the recovered one, since their correlation is 0.9849, for gray-scale images, and 0.9840,
for color images.
Correlation Between α ( ν , r ) and
Across CMU, CSIQ, and IVCIMAGE Databases
Image Database 8 bpp Gray-Scale 24 bpp Color
Figure 6 depicts the PSNR difference (dB) of each color image of the CMU database, that is,
the gain in dB of image quality after applying at d = 2000 cm to the images. On av-
erage, this gain is about 15 dB. Visual examples of these results are shown in Figure 7 , where
the right images are the original images, central images are perceptual quantized images after
applying α ( ν , r ), and left images are recovered images after applying
FIGURE 6 PSNR difference between Q image after applying α ( ν , r ) and recovered
for every color image of the CMU database.
FIGURE 7 Visual examples of perceptual quantization. Left images are the original images,
central images are forward perceptual quantized images (F-pSQ) after applying
d = 2000 cm, and right images are recovered I-pSQ images after applying
. (a) Girl 2.
(b) Tiffany. (c) Peppers.
After applying , a visual inspection of these 16 recovered images shows a perceptu-
ally lossless quality. We perform the same experiment for gray-scale and color images with