Specifically have aloo at the sections:. It seems your feature extractor usually use corners while you need more general purpose features. Since your search should be not care about rotations At least according to your examples what you can do is a template matching over the features and not the image.
Namely you are after a scaling of the feature location of your template in the image. I believe Haar Cascades used by Viola-Jones are inherently scale-invariant. Also severely deprecated by modern Neural Networks, but I know nothing about those.
It also doesn't do any OCR - if you need that you would need to run a separate algorithm on the extracted sub-image. Why not try to program it by percentage from the beginning? Like this, it's scalable in any resolution. Loop and checking would only generate more work and consume more resources.
If there is a way to display the elements by percentage, you get the result in any resolution. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Learn more. Asked 6 months ago. Active 6 months ago. Viewed times. What I tried so far is: Rescaling the template at different resolutions in a loop and checking.
As soon as my result increases above a certain threshold, I consider it a match. I don't know if I am missing something, but it doesn't look like those algorithms are made for what I am trying to do. I am getting results like this: Any help or ideas are highly appreciated! Next, we create a blank image the will hold the correlation map:. See the weird size we're giving this image? That has a perfectly sane explanation. Have a look at the picture below:. The correlation map can only extend from the top left corner to the big black dot on the lower right corner.
Thats because if the template were to slide any further, you'd get a partial template image So you subtract the height and width of the template from the original image's height and width, and add one. This instruction does all the sliding and correlation mathematics using imgOriginal the source , imgTemplate the template and puts the correlation map into imgResult. This function returns the minimum and maximum values and their locations.
So, we use it:. We'll just put a rectangle there, and also print out the actual value of correlation That seems very accurate. I got a correlation of 0. That's because of the little R. It isn't present in the template, so it takes its toll. That, and the fact that JPEG images put a little noise around the edges, combined reduce the correlation. Well, the first disadvantage is that you need to know what you're looking for. If you're looking for dynamic features, you'll be better off using some other techniques.
Secondly, template matching provided by OpenCV doesn't let you check for rotations and scalings. If the P in our example was rotated by 90 degrees, the current program would never find it. You could write code for it though. A brute force algorithm would be to generate all possible rotations, all possible scales and then do the matching.
But that would be extremely slow. So again, use some other techniques. The aim of this project is to use a down facing camera as a range and bearing sensor for a quadcopter for localization purposes. The environment and robot is simulated in a robot simulator V-REP, the environment consists of a 10mx10m grid with colored markers placed at regular intervals. Performance of different algorithms for marker detection is evaluated based on the error in the localization accuracy.
The algorithms used are contour detection, template matching and phase correlation. Image key points Extraction, Description, Feature Matching. Data sets are also included to test the algorithms. Add a description, image, and links to the template-matching topic page so that developers can more easily learn about it. Curate this topic. To associate your repository with the template-matching topic, visit your repo's landing page and select "manage topics. Learn more. Skip to content. Here are public repositories matching this topic Language: All Filter by language.
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