Recognizing finder patterns of QR code using MAT LAB.

Hello, i am working on encoding and decoding Covert QR codes using MAT LAB. i encoded three different QR code containing messages "hello", "what", "how" using Zxing, an open source and MAT LAB.

After encoding these three codes were saved as .jpg image and the finder patterns (ie. the three square boxes) were identified using MAT LAB. then top left square of image1 and its background was changed to colored red color, lower left sqaure and background of image 2 to blue and upper right square and background to green in MAT LAB using centroid,area and bounding box properties. they were saved as jpg image.

After that these three individual codes were added up to form a single RGB colored QR code.

The problem is when i am trying to decode it, by removing layers of colors one by one (ie by making R and G as zero) for 1st time and (G and B) to zero second time. the pixels are not turning to zero of the colored image and i ma not able to decode it. Kindly tell where the problem is arising.

Attaching MAT file which contains the code being used for detection of finder pattern and changing background color. Please help out.

[Sanket Salvi]

I had similar issue, i found out the after extracting the corresponding channel while performing imbinarize i was suppose to pass dynamic threshold value.