PhotoSqueak 1.0

by Juan Manuel Vuletich
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Part 2

Exercise 1

    It was asked to implement the Thershold operation, and the binarization of an image with a threshold level. I didn't include any example here, but you can try them if you want.

Exercise 2

    It was asked to be able to apply any function to the pixel values of an image, and/or to the histogram, calculating the new image and/or histogram.

Exercise 3

    It was asked to implement the convolution operation of two images. As this is a numerically expensive operation, I used Squeak C code generation, from the already tested Smalltalk code. This C code was compiled both as a OS/2 and as a Windows dll, that is automatically called if present (if it is not present, the slower Smalltalk code is invoked). This way, times ranging from 2 to 10 minutes went down to 2 to 10 seconds. In this sample screen, it can be seen how a low pass filter emphatizes borders. In the center image, black or large negative values, and white or large positive values are boteh borders. The image on the right, is the center image squared. So, borders are bright white, and non-borders are black. Several other filters were also used.