如何比较两个边缘图像(在 OpenCV 中)? [英] How do I compare two edge-images (in OpenCV)?
问题描述
in my project i need to compare to images. One image shows a render-model and the other image is a photo, in which the real object, which is represented in the model, is shown. What i exactly want:
- The algorithm has to compare the two images and return a number, that describes the similarity. Let's say the lower the number is, the better the images fit together.
- Both images are represented as binary images which only contain the contours / edges of the real render-image / photo.
- The photo has a lot more objects in it than the render-image. So i only want to check if the viewpoint to the render-object is nearly the same than the viewpoint to the real object in the photo. (Example: A car is modelled so it approximates a real car. I take a photo of the real car from a special position and orientation. Now i want to check, if the position and orientation of my virtual camera looking at the render-car is nearly the same, than the position and orientation of my real-life-camera). The solution is only to compare the white pixels of the render image to the pixels of the photo (as edge-image). The other pixels are not interesting.
- The returned value of the image-comparision should decrease the better my orientation and position of the virtual camera fits to the real camera's orientation and position.
I tried to calculate the euclidian distance of the two images but the result is only good, when the pixels exactly fit to each other. Now i am searching for alterantives.
Until now i considered to use the normalized cross-correlation, but i really dont know if it fits to my task.
The question is, if the normalized cross-correlation is worth a try or if there are better methods of solving my problem!
The algorithm should be as fast as possible, because i compare a lot of images.
Thanks a lot
Thanks for your suggestions. I am a little confused due to the fact that the normalized cross-corellation and Haussdorff distance seem to be good for finding a small pattern in a big picture.
The question is: Are the two algorithms also good for comparing 2 pictures of the same size?
Here is an example of 2 images that have to be compared. At the moment i am comparing around 120 pictures-paires a second.
Too bad that i cannot post images as a new user. So here is the direct link: http://s14.directupload.net/file/d/2674/t8qzbq9i_png.htm
How about experimenting with the Haussdorff distance as a starting point? General idea and c implementation here. Article here:
Comparing images using the Hausdorff distance, by DP Huttenlocher - 1993.
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