Find all local maximum from mata image in openCv

I am currently trying to localize a barcode and I want to get the local maximum etch pixel information in a matte image. Here is the code

    /**Applying Canny**/ 
  Imgproc.Canny(mGray, mGray, 80, 90);
  Imgproc.threshold(mGray, mGray, Imgproc.THRESH_OTSU, 255, CvType.CV_8UC1);
  Size ksize=new Size(31,31);
  Imgproc.blur(mGray, mGray, ksize);

      

        
        
        
      

    

local maximum list = max (mGray)