Find occurrences of smaller image in a bigger image

What procedure is needed if I want to find a template in an image?
A subimage in a bigger image?
For example in an image of a pdf with text, find all the occurrences of the letter “a”.

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Although I am not exactly sure, I think this is a classic pattern recognition problem in computer version, and it can be achieved by opencv-does not have to use DL.

If you’re not just working with text, you might be looking for image segmentation, e.g. faster r-cnn, which locates (& IDs) objects within an image.

See this forum for more examples & details

If you’re really just looking for smaller versions of an image in a bigger image, you should look into features like SIFT, SURF, ORB, etc.

It sounds like this tutorial is pretty close to what you’re looking for…

Those won’t work on text (document image).

This is a computer vision problem but the old way is feature engineering, that’s why I’m asking for a DL method.

Don’t see why key point extraction wouldn’t work for your example (especially if looking for individual letters). You could also just do cross correlation with the letter at a few scales and rotations.

If all the same font, deep learning is really over powered for this problem.

The methods used in lesson 7 should work.

Any new code/projects for template matching?