Opencv finds image cordinates on another image

Question

How to find the image The coordinates "A" on the image "B", which contains the image "A".

I wrote this program that checks only pixel values, does anyone know if there is any library tool.

Answer 1

As Throwback1986 suggested, you probably want to use matchTemplate . Here is one of my answers showing how to detect the sun from a virtual spaceship. Here is the new OpenCV tutorial on using matchTemplate . Now there are some caveats for using the matchTemplate approach. If image “A” can be in any position (for example, zooming, rotation, perspective, etc.) on image “B”, then matchTemplate will not work very well. If this happens, you will want to use the function discovery route, as suggested by Adrian Popovich.

Answer 2

You should take a look at the last 3 tutorials at this link: http://opencv.itseez.com/doc/tutorials/features2d/table_of_content_features2d/table_of_content_features2d.html

I don't think pixel checking is a good approach.

Answer 3

You might consider something like pattern matching, as described in this tutorial .

A rougher approach is to “slide” the image. Gradually over the image B searches for the point of least difference. (Note that this assumes that image A is some fairly small subset of image B.) You can use the cvNorm function to calculate, which is equivalent to calculating the sum of squared differences (SSD). Use parameter CV_L1. Here is a link describing the use of SSD in image correlation.