Same test image as yesterday 4000×4000 monochromatic, 16-bit gray gamma 2.2, filled with a constant signal of half-scale, (0.5, 127.5, or 32767.5, depending on how you think of it), with Gaussian noise with standard deviation of 1/10 scale added to it. The image was created in Matlab, written out as a 16-bit TIFF, read into… [Read More]

When I last left you, the jury was out on the issue of whether the bilinear interpolation downsizing algorithm in Photoshop was the same as the one in Matlab. The jury is back. “Mr. Foreman, have the jury reached a verdict?” “We have, your honor.” “May I hear it?” “The algorithms are wildly different, as… [Read More]

In the two previous posts, I identified some anomalies with Matlab’s implementation of bilinear interpolation downsampling at reduction ratios that are integral powers of two. I also observed smaller, but similar, anomalies with bicubic, Lanczos 2, and Lanczos 3 downsampling. Today I set out to find out if the Photoshop implementations of bilinear interpolation evinced… [Read More]

[Note. The bilinear and bicubic interpolation algorithms referred to in this article are the Matlab implementations. They are different from the Photoshop algorithms of the same or similar names. The Photoshop versions are reported on a few posts further on. Therefore, this post is primarily of academic interest.] In yesterday’s post I reported on the… [Read More]

[Note. The bilinear and bicubic interpolation algorithms referred to in this article are the Matlab implementations. They are different from the Photoshop algorithms of the same or similar names. The Photoshop versions are reported on a few posts further on. Therefore, this post is primarily of academic interest.] It is axiomatic in photography that photon… [Read More]