Just noticeable difference in black level, white level and chroma for natural images measured in two different countries

The just noticeable difference (JND) in black level (BL), white level (WL), and chroma as visible in natural images under practical viewing conditions is determined. The same experiments are conducted in China and in the Netherlands to evaluate possible ethnic differences in the size of JNDs. In both countries, there is a strong effect of image content on the JND of BL and WL, while for most images used in this experiment no content dependency is found for the JND of CS. For most images, there is no difference in JND of WL and CS between China and the Netherlands. For some images, we found a difference in JND of BL between China and the Netherlands, but this difference most probably is related to the fact that the viewers looked to a different part in the image, rather than to an ethnic difference.