aforge之hough

 /// <summary>
        /// 参数不能是一位索引
        /// </summary>
        /// <param name="bmp"></param>
        /// <returns></returns>
        public Bitmap HoughTransform(Bitmap bmp)
        {
            //// create filter
            //Median Medianfilter = new Median();
            //// apply the filter
            //Medianfilter.ApplyInPlace(bmp);
            Bitmap grayImage;
            if (bmp.PixelFormat != PixelFormat.Format16bppGrayScale && bmp.PixelFormat != PixelFormat.Format8bppIndexed)
            {
                Grayscale grayscalefilter = new Grayscale(0.2125, 0.7154, 0.0721);
                grayImage = grayscalefilter.Apply(bmp);
            }
            else
            {
                grayImage = bmp;
            }
            // invert filter
            Invert invertfilter = new Invert();
            // apply the filter
            invertfilter.ApplyInPlace(grayImage);
            //// Edge Detector  filter
            DifferenceEdgeDetector EdgeDetectorfilter = new DifferenceEdgeDetector();
            //// apply the filter
            EdgeDetectorfilter.ApplyInPlace(grayImage);
            //// create filter
            Dilatation dilatationfilter = new Dilatation();
            //// apply the filter
            dilatationfilter.ApplyInPlace(grayImage);

            return grayImage;
        }