Image processing effects

[gkec]

When I worked on image processing systems we used to generate test images as camera were not always available or convienient.

The images were 16 bit monochrome and there were various methods of reducing the 16 bits to 8 bit RGB.  A quick way was to take a window of 8 bits and use that as the RGB values creating an 8 bit mono image.

Most images were quite boring bt buy setting each pixel to x² * y² where x and y are the pixel coordinates something rather surprising happened.  

Initially  you get a sort of sphere effect which isn't surprising, but when the window is shifted down the image looks very different. The attached program demonstrates this, just open in it your browser and slide the little slider.  

testimage.html