Colorization Chapter

The portrait experiment



This is a lower-resolution page, more convenient for an overview. Click on images to zoom.

All paintings below are, if I do not mistake, in the public domain and consequently free of rights.

Page map: training set / test set / results (to be updated regularily)


Training set (53 images)

These images are given as examples, in order to know what a color image looks like.
training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image training image




Test images (5 images)

The following images are converted into grey-scale values, and will be used later as test images.
test image test image test image test image test image

Note that there can be issues concerning the true colors of a painting. For example compare :
test image test image




Results

I modified the original training set, removing two images and down-sampling the biggest images, so that it fits the RAM during learning and prediction without requiring a program structure change; I updated the training set above accordingly.
The following result is based on all the training images above. Same parameters for the all test images. Pixels on a 3x3 grid only were colored.
For each test image are displayed:


grey image final result color predicted color variation predicted best color locally
grey image final result color predicted color variation predicted best color locally
grey image final result color predicted color variation predicted best color locally
grey image final result color predicted color variation predicted best color locally
grey image final result color predicted color variation predicted best color locally



Notes : Now let us perform other tries, with different values for the parameter of color spatial coherency, all other parameters being kept constant (to the values used in the first experiment, not shown here). Have a look at the summary page with all results of this set of experiments, practical to see the effects of the spatial coherency parameter (you can click on one experiment to access its personal web page).

Summary for a second set of experiments with more parameters varying. The experiment shown above is experiment 45.


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