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It tries to generate an absolute value that represents the perceived difference between two images. Some clever minds have thought about it and developed the SSIM algorithm to simulate the perception of our eyes. How do you compare the quality of two images?Īt which quality level do they look good enough?Īnd as of when do compression artifacts interfere?ĭepending on the intended purpose and person, the answers will vary considerably. How do you assess the results of the tools? The test image, which serves as the basis for all diagrams and comparisons, is this one: Probably the best known tools are in the ring: So I will compare the features of each tool and see where they have their strengths and weaknesses.Īnd of course I will test the actual JPEG compression capabilities and how the tools compare to Compress-Or-Die. There is only the optimal tool for a certain purpose. Unfortunately, such statements are made regardless of which settings have been made and without considering the consequences for the respective target group (photographer, web developer, ad developer etc.) or the respective application purpose (archiving, website presentation, printing etc.).īasically, THE tool does not exist. Usually they end with a simple: "It generates smaller pictures, so it's got to be better." There are a lot of articles about online image compression tools in the net, most of them are very superficial.
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