Ask Your Question

Revision history [back]

Keypoints in very small images

I want to find a very small image (20x20px) within a small image (~400x250) using OpenCV. Here is an example:

small image

very small image

The problem is as follows: I can't use template matching because of partial obstruction and sub-pixel rendering on the bigger image (which is rendered in-game and leads to 1-2 pixels difference.) However, keypoint extraction seems to fail with most methods, because the input image is very small (20x20px colored within a 32x32 template.) Simply increasing the 20px image in size did not really work.

Currently, I am out of ideas, although the task seems simple enough. Is there an algorithm within OpenCV that suits this problem?

click to hide/show revision 2
No.2 Revision

updated 2017-05-19 09:27:41 -0500

berak gravatar image

Keypoints in very small images

I want to find a very small image (20x20px) within a small image (~400x250) using OpenCV. Here is an example:

small imagesmall image

very small imagevery small image

The problem is as follows: I can't use template matching because of partial obstruction and sub-pixel rendering on the bigger image (which is rendered in-game and leads to 1-2 pixels difference.) However, keypoint extraction seems to fail with most methods, because the input image is very small (20x20px colored within a 32x32 template.) Simply increasing the 20px image in size did not really work.

Currently, I am out of ideas, although the task seems simple enough. Is there an algorithm within OpenCV that suits this problem?

click to hide/show revision 3
No.3 Revision

updated 2017-05-19 09:28:24 -0500

berak gravatar image

Keypoints in very small images

I want to find a very small image (20x20px) within a small image (~400x250) using OpenCV. Here is an example:

small imagesmall image

very small imagevery small image

The problem is as follows: I can't use template matching because of partial obstruction and sub-pixel rendering on the bigger image (which is rendered in-game and leads to 1-2 pixels difference.) However, keypoint extraction seems to fail with most methods, because the input image is very small (20x20px colored within a 32x32 template.) Simply increasing the 20px image in size did not really work.

Currently, I am out of ideas, although the task seems simple enough. Is there an algorithm within OpenCV that suits this problem?