detectEdgePixels

Takes an ImageData object and a number.
Returns an ImageData object.

The imageData input is the image that you want to detect edge pixels in.

The number input is the minimum difference between two pixel colour values (0 - 255) that constitutes a significant change.

The output is a black and white image, where the edge pixels are white.

jsia.detectEdgePixels(imageData, 16);
//detects pixels where the contrast between a pixel 
//and its neighbour is at least 16.