I didn't spot this by myself. A reader first tipped me off to the similarities between the U24 …
Instead of perturbing each pixel in the input image at random, we can choose to dither by a predetermined amount depending on the pixel’s position in the image. This can be achieved using a threshold map; a small, fixed-size matrix where each entry tells us the amount by which to perturb the input value , producing the dithered value . This matrix is tiled across the input image and sampled for every pixel during the dithering process. The following describes a dithering function for a 4×4 matrix given the pixel raster coordinates :
，详情可参考下载安装 谷歌浏览器 开启极速安全的 上网之旅。
FT App on Android & iOS
Artie Beaty, Contributing WriterContributing Writer