What is the least JPG-compressible pattern? (camera shooting piece of cloth, scale/angle/lighting may vary) I am trying to design a cloth that, from the point of view of a camera, is very difficult to compress with JPG, resulting in big-size files (or leading to low image quality if file size is fixed).

It must work even if the cloth is far away from the camera, or rotated (let's say the scale can vary from 1x to 10x).

Noise is quite good (hard to compress), but it becomes grey when looking from far, becoming easy to compress. A good pattern would be kind of fractal, looking similar at all scales.
Foliage is better (leaves, tiny branches, small branches, big branches), but it uses too few colors.

Here is a first try:


I am sure there are more optimum patterns.
Maybe hexagon or triangle tessellations would perform better.

JPG uses the Y′ Cb Cr color space, I think Cb Cr can be generated in a similar way, but I guess it's better to not use uniformly the full scope of Y' (brightness) since camera will saturate the bright or dark areas (lighting is never perfect).

QUESTION: What is the optimum cloth pattern for this problem?
Noise is quite good (hard to compress), but it becomes grey when looking from far, becoming easy to compress. A good pattern would be kind of fractal, looking similar at all scales.


Well, there is fractal noise.  I think Brownian noise is fractal, looking the same as you zoom into it.  Wikipedia talks about adding Perlin noise to itself at different scales to produce fractal noise, which is maybe identical, I'm not sure:



I don't think this would be hard to compress, though.  Noise is hard for lossless compression, but JPEG is lossy, so it's just going to throw away the detail instead of struggling with it.  I'm not sure if it's possible to make something "hard for JPEG to compress" since it will just ignore anything that's too hard to compress at that quality level.

Something with hard edges at any scale would probably be better, like the infinite checkerboard plane:



Also something with lots of colors.  Maybe look at actual fractals instead of fractal noise.  Maybe a Mondrian fractal?  :)