CODEWITHSUNDEEP
image-processingjavacvthreshold
LkDev
LkDev

Reputation: 221

Improve the quality by applying adaptive threshold in javacv/opencv ?

I'm try to improve my image quality by applying following shareholding to input image.

        CvSize sz = cvSize(img.width(), img.height());
        IplImage gry = cvCreateImage(sz, img.depth(), 1);
        cvCvtColor(img, gry, CV_BGR2GRAY);
        cvAdaptiveThreshold(gry, gry, 255, CV_ADAPTIVE_THRESH_MEAN_C, CV_THRESH_BINARY_INV, 5, 4);

This is my input file

enter image description here

by applying threshold I need to draw all the lines in white and all other areas in black but in my out put there are some missing lines. So please can some one explain how to overcome with this problem ?

This is my out put after applying above threshold.

enter image description here

Upvotes: 3

Views: 4486

Answers (2)

tofi9
tofi9

Reputation: 5853

I hope you've already found the answer, if not.... Try some gaussian blur before you threshold:

Mat image = imread("mX5h6.jpg", IMREAD_GRAYSCALE);
GaussianBlur(image, image, Size(3, 3), 0, 0);
adaptiveThreshold(image, image, 255, CV_ADAPTIVE_THRESH_MEAN_C, CV_THRESH_BINARY_INV, 5, 4);
imshow("image", image);

Upvotes: 1

mkuse
mkuse

Reputation: 2488

you should do erosion (cvErode() in opencv) and then dilate (cvDilate()) to get rid of the small speckles. Hope this helps

Upvotes: 2

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