Digital watermarking using hough transform ??

what purpose has hough transform to tattoo a medical image (I want to use non-exploitable black part of the image) !!

[Image Analyst]

I don't know what purpose. I don't even understand the question. http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[mohamed yassine ben homrane]

how I can use the Hough transform to insert information in a picture"watermarking" (I want to determine the maximum from the hough space to insert information)