As you might imagine, it’s quite a complex procedure that involves scanning the digits already present and working out which squares are blank.

Processing the scanned image requires setting a threshold value to remove noise, segmenting to work out which marks are part of the digit, thinning to one pixel wide and then checking the features to find out what the digit is.

Solving the Sudoku puzzle is the relatively easy bit, though the Mindstorm processor is slow and doesn’t allow recursive functions, so took some time to optimize.

Then comes the time to write in all those digits, column by column. The whole process is very slow, for all sorts of reasons, and it won’t be beating a human Sudoku champion any time soon (even if it solved the puzzle more quickly), but that’s not the point. This is a trés cool application.

Read more at Tilted Twister