Appendices - Feature Extraction and Image Processing - page 325

So we'll equalise our eye: new_pic:=equalise(eye)

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35 43 78 78 64 64 47 26 45 59

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new_pic = 64 64 64 78 68 43 26 52 47 61 78

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(a) (b)

This is how Mathcad displays images when you display them using the surface plot
facility (which is why we're using the picture facility instead, it's faster too!). Now try
equalising the image brighter (as defined earlier) - do you expect the result you get?
The histogram tells us what has really happened to the picture: e_hist:=histogram
(new_pic)

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e n_hist bright

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Bright

One way of interpreting this is that the histogram is now balanced between black and
white.