opecv获取图像轮廓

获取轮廓

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#import <opencv2/opencv.hpp> #import <opencv2/imgcodecs/ios.h> #import <opencv2/imgproc/types_c.h>   @implementation OpenCVHelper +(UIImage *)getImageOutLine:(UIImage *)iputimg {     cv::Mat cvImage;     UIImageToMat(iputimg, cvImage);     cv::Mat gray;     // Convert the image to grayscale;     cv::cvtColor(cvImage, gray, CV_RGBA2GRAY);     // Apply Gaussian filter to remove small edges     cv::GaussianBlur(gray, gray, cv::Size(5,5), 1.2,1.2);     // Calculate edges with Canny     cv::Mat edges;     cv::Canny(gray, edges, 0, 60);     // Fill image with white color     //cvImage.setTo(cv::Scalar(255,255,255,1));     // Change color on edges     // cvImage.setTo(cv::Scalar(0,128,255,255),edges);           cv::Mat cvOutImage= cv::Mat::zeros(cvImage.size(), cvImage.type());     cvOutImage.setTo(cv::Scalar(255,255,255,0));     cvOutImage.setTo(cv::Scalar(0,139,139,1),edges);     return MatToUIImage(cvOutImage);   } @end

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-(UIImage *)transparentImage:(UIImage *)image {           // Create a pixel buffer in an easy to use format     CGImageRef imageRef = [image CGImage];     NSUInteger width = CGImageGetWidth(imageRef);     NSUInteger height = CGImageGetHeight(imageRef);     CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();           UInt8 * m_PixelBuf = malloc(sizeof(UInt8) * height * width * 4);           NSUInteger bytesPerPixel = 4;     NSUInteger bytesPerRow = bytesPerPixel * width;     NSUInteger bitsPerComponent = 8;     CGContextRef context = CGBitmapContextCreate(m_PixelBuf, width, height,                                                  bitsPerComponent, bytesPerRow, colorSpace,                                                  kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);           CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);     CGContextRelease(context);           //alter the alpha     int length = height * width * 4;     for (int i=0; i<length; i+=4)     {         if (m_PixelBuf[i+0] ==255) {             m_PixelBuf[i+0] =0;             m_PixelBuf[i+1] =0;             m_PixelBuf[i+2] =0;             m_PixelBuf[i+3] =0;         }        }                 //create a new image     CGContextRef ctx = CGBitmapContextCreate(m_PixelBuf, width, height,                                              bitsPerComponent, bytesPerRow, colorSpace,                                              kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);           CGImageRef newImgRef = CGBitmapContextCreateImage(ctx);     CGColorSpaceRelease(colorSpace);     CGContextRelease(ctx);     free(m_PixelBuf);           UIImage *finalImage = [UIImage imageWithCGImage:newImgRef];     CGImageRelease(newImgRef);           return finalImage; }