Can anyone explain why destroying through remixing a digital image produces all these artifacts? For instance, why does the text at the bottom just spit up all those pixels? Or why did a boundary just start to appear that was never in the original image?
I'll take a stab at it. This image, which is an intermediate image in the process, is a jpeg.
So Mark, the "almost white" is the anti-aliasing around the text?
Not quite anti-aliasing, but similar in that it represents a smearing function. Quantization noise is the precise term. It manifests as more of a splotchy smearing than a smooth smearing.
I forced the colors to change but what was weird is that the white around the letters is actually different shades instead of a uniform field.
Okay, here's an attempt at a simple explanation of anti-aliasing and jpeg quantization. I started with the image below: the letter in in Times New Roman. The letter is anti-aliased, which gives it nice smooth edges.
The detail below shows how the smooth edges are acheived. Rather than an abrupt transition from black to white, there are various shades of grey pixels to create the illusion of smooth curves. This techniqe is very common in digital displays and printing.
The image below is detail of the same letter having passed through jpeg at a high compression ratio. Jpeg compression introduces what is known as "quantization noise". In jpeg compression, the pixels are divided into blocks, and the blocks of pixels are decomposed into a set of wave representations, which are then approximated (quantized). When a jpeg is displayed, the quantized waves are converted back into pixels. Because of the decomposition and approximation process, blockiness, wave-like spotches, and splatters are introduced into the image.
This looks like this is another occassion where i can plug my article
Nice article, thanks.
This all started because I was making some little jokes (extremely little).
Mark's and drx's previous writings on this topic had me up to speed so I could indulge in this humor. Also I had earlier posted Paul Slocum's "bad jpeg" as a cross stitch pattern (his idea--I ran it through KnitPro). Now e has been indoctrinated into the mysteries of bicubic mush
The images are cool whether or not one knows the underlying math. I especially like image in the post above this one. I've been dealing with image processing for so many years, it's hard for me not to think about what's going on. Can painters look at others' paintings without visualizing brushes and palette knives?
I changed aka to and/or. I didn't know bicubic mush had such a precise technical meaning--I thought it was a cute way of referring to the characteristic blotchiness that results from resizing or overprocessing an image. Since "mush" is more pejorative than "smoothing."
Tom sorry for making your references to me a pain. I’ll officially use ‘e’ as my name since I have been using ‘j’ jenghizkhan, John, earcon.
I really like this area of working that I feel I just discovered for myself even though it has been going on for a while on this blog.