Extract cow number from image

Question

every now and then my mom has to shift through these type of photos to extract the number from the image and rename it to the number.

Answer 1

I have been looking at this a little and thinking how I might tackle it. I prefer the free ImageMagick software which is available for OSX, installed on most Linux distros and available for Windows.

My first reaction was to try a Sobel edge detector to the images, then threshold that and remove noise and outliers with a median filter.

I can do all that with a single command at the commandline like this:

convert c1.jpg                                                          \
   -define convolve:scale='50%!' -bias 50% -morphology Convolve Sobel   \
   -solarize 50% -level 50,0% -auto-level -threshold 50% -median 3 result.jpg

where c1.jpg is your first cow, and likewise for the other cows.

I end up with this:

which is a pretty reasonable starting point for working out where the numbers are in the image. I am thinking of dividing the image into tiles next, or other techniques, and then I will look at tiles/areas containing the most white. That way I will start to get a handle on where I should be pointing tesseract to look... however, it is bedtime - apparently. Maybe someone clever like @rayryeng will take a look overnight :-)