private BitmapHoughTransFormLine(Bitmap bmp)

{

Mat rgbMat = new Mat();  //存储原图像的矩阵

Mat grayMat = new Mat(); //存储灰度图像的矩阵

Mat lineMat = new Mat(); //存储检测出的直线坐标的矩阵，每个element有4个通道，第1、2个通道为直线的1个端点，第3、4个通道为直线的另1个端点

Utils.bitmapToMat(bmp, rgbMat);

Imgproc.cvtColor(rgbMat,grayMat, Imgproc.COLOR_RGB2GRAY); //灰度化

Imgproc.Canny(grayMat, grayMat,50, 200);                  //Canny边缘检测

/* Hough变换标记直线

* public static void HoughLinesP(Matimage, Mat lines, double rho, double theta, int threshold)

*    image - 8-bit, single-channel binary source image. The image may bemodified by the function.

*    lines - Output vector of lines. Each line is represented by a 4-elementvector (x_1, y_1, x_2, y_2),

*                where (x_1,y_1) and (x_2, y_2) arethe ending points of each detected line segment.

*    rho - Distance resolution of the accumulator in pixels.

*     theta - Angle resolution of theaccumulator in radians.

*    threshold - Accumulator threshold parameter. Only those lines arereturned that get enough votes (>threshold).

*/

Imgproc.HoughLinesP(grayMat,lineMat, 1, Math.PI/180,50, 50.0, 10.0);

int[] a = new int[(int)lineMat.total()*lineMat.channels()]; //数组a存储检测出的直线端点坐标

lineMat.get(0,0,a);

for (int i = 0; i < a.length; i += 4)

{

Core.line(grayMat, new Point(a[i], a[i+1]), new Point(a[i+2], a[i+3]), new Scalar(255, 0, 255),4);

}

//创建一个图像

Bitmap newBmp = Bitmap.createBitmap(bmp.getWidth(),bmp.getHeight(), Config.RGB_565);

//将矩阵grayMat转换为图像

Utils.matToBitmap(grayMat,newBmp);

rgbMat = null;

grayMat = null;

lineMat = null;

a = null;

return newBmp;

}