# Compare font from image

I am trying to compare the 3 fonts from the image. I want some algorithm witch will say 2 and 3 are matching fonts but 1 is not matching font. I have tried this approach using HuMoments, but it does not seem to work. https://stackoverflow.com/questions/5...

Is there any other way to find how much similar one font is to the other from the images ?

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define similar.

( 2019-06-15 04:31:11 -0500 )edit

@berak, image 2 and 3 have font Adobe Arabic Bold hence image 2 and 3 are similar . From the given figure we can infer that image 1 does not match in font to image 3. Hence image 1 and image 3 are not similar

( 2019-06-16 01:46:58 -0500 )edit

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Here's one solution. Do a binary inverse threshold so the letters are white and background is dark. Use findContours function with the RETR_EXTERNAL setting to get a contour for each of the 8 letters. Sort these contours by their x value so that they are in order left to right. Do this for 2 different font images so that you have 2 sets of 8 contours. For each contour pair, get their boundingRects. Extract the 2 roi's and resize one if they are not the same size. Then use template matching to compare the two roi's (I used TM_CCOEFF_NORMED). In the match or score image find the max score with minMaxLoc Notice the scores below are much higher for pairs from the same font than for a different font.

    vector<vector<Point>> srcContours;
vector<vector<Point>> src2Contours;
Mat templImg, testImg;
Mat scoreImg;
double maxScore;

Mat templClrImg, testClrImg;
Mat compImg;

findContours(srcImg, srcContours,   RETR_EXTERNAL, CHAIN_APPROX_NONE);
findContours(src2Img, src2Contours, RETR_EXTERNAL, CHAIN_APPROX_NONE);

sort(srcContours.begin(), srcContours.end(), [](const vector<Point>& a, const vector<Point>& b) {
Point2f actr = ContourFindCenter(a);
Point2f bctr = ContourFindCenter(b);
return actr.x < bctr.x;
});

sort(src2Contours.begin(), src2Contours.end(), [](const vector<Point>& a, const vector<Point>& b) {
Point2f actr = ContourFindCenter(a);
Point2f bctr = ContourFindCenter(b);
return actr.x < bctr.x;
});

for (int i = 0; i < srcContours.size(); ++i) {
Rect rect = boundingRect(srcContours[i]);
Rect rect2 = boundingRect(src2Contours[i]);

templImg = Mat(srcImg, rect);
testImg = Mat(src2Img, rect2);
if (rect != rect2) {
resize(testImg, testImg, rect.size());
}

matchTemplate(testImg, templImg, scoreImg, TM_CCOEFF_NORMED);
minMaxLoc(scoreImg, 0, &maxScore, 0, 0);
}


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