使用 OpenCV 在 iPhone 中进行人脸跟踪答案

【问题标题】：Face Tracking in iPhone using OpenCV使用 OpenCV 在 iPhone 中进行人脸跟踪
【发布时间】：2011-09-07 20:29:36
【问题描述】：

我想在 iPhone 中创建与 code 一样的面部跟踪。它是一个 mac os 代码，但我想在 iPhone 中使其与给定代码相同。

关于在 iphone 中进行面部跟踪的任何想法。

【问题讨论】：

【解决方案1】：

您必须使用 OPENCV 检测人脸并将其导入您的代码。在这种方法中，我使用矩形/椭圆来表示检测到的人脸

-(UIImage *) opencvFaceDetect:(UIImage *)originalImage {

    cvSetErrMode(CV_ErrModeParent);

    IplImage *image = [self CreateIplImageFromUIImage:originalImage];

    // Scaling down

    /*
      Creates IPL image (header and data) ----------------cvCreateImage
      CVAPI(IplImage*)  cvCreateImage( CvSize size, int depth, int channels );
     */

    IplImage *small_image = cvCreateImage(cvSize(image->width/2,image->height/2), IPL_DEPTH_8U, 3);

    /*SMOOTHES DOWN THYE GUASSIAN SURFACE--------:cvPyrDown*/
    cvPyrDown(image, small_image, CV_GAUSSIAN_5x5);
    int scale = 2;

    // Load XML
    NSString *path = [[NSBundle mainBundle] pathForResource:@"haarcascade_frontalface_default" ofType:@"xml"];
    CvHaarClassifierCascade* cascade = (CvHaarClassifierCascade*)cvLoad([path cStringUsingEncoding:NSASCIIStringEncoding], NULL, NULL, NULL);

    // Check whether the cascade has loaded successfully. Else report and error and quit

    if( !cascade )
    {
        NSLog(@"ERROR: Could not load classifier cascade\n");
        //return;
    }

    //Allocate the Memory storage
    CvMemStorage* storage = cvCreateMemStorage(0);

    // Clear the memory storage which was used before
    cvClearMemStorage( storage );

    CGColorSpaceRef colorSpace;
    CGContextRef contextRef;


    CGRect face_rect;
    // Find whether the cascade is loaded, to find the faces. If yes, then:
    if( cascade )
    {
        CvSeq* faces = cvHaarDetectObjects(small_image, cascade, storage, 1.1f, 3, 0, cvSize(20, 20));
        cvReleaseImage(&small_image);

        // Create canvas to show the results
        CGImageRef imageRef = originalImage.CGImage;
        colorSpace = CGColorSpaceCreateDeviceRGB();
        contextRef = CGBitmapContextCreate(NULL, originalImage.size.width, originalImage.size.height,
            8, originalImage.size.width * 4, colorSpace,
            kCGImageAlphaPremultipliedLast|kCGBitmapByteOrderDefault);
        //VIKAS
        CGContextDrawImage(contextRef, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), imageRef);

        CGContextSetLineWidth(contextRef, 4);
        CGContextSetRGBStrokeColor(contextRef, 1.0, 1.0, 1.0, 0.5);

        // Draw results on the image:Draw all components of face in the form of small rectangles
        // Loop the number of faces found.
        for(int i = 0; i < faces->total; i++) 
        {
            NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

            // Calc the rect of faces
            // Create a new rectangle for drawing the face

            CvRect cvrect = *(CvRect*)cvGetSeqElem(faces, i);
            // CGRect face_rect = CGContextConvertRectToDeviceSpace(contextRef, 
            //     CGRectMake(cvrect.x * scale, cvrect.y * scale, cvrect.width * scale, cvrect.height * scale));

            face_rect = CGContextConvertRectToDeviceSpace(contextRef, 
                CGRectMake(cvrect.x*scale, cvrect.y, cvrect.width*scale, cvrect.height*scale*1.25));

            facedetectapp=(FaceDetectAppDelegate *)[[UIApplication sharedApplication]delegate];
            facedetectapp.grabcropcoordrect=face_rect;

            NSLog(@"  FACE off %f %f %f %f",facedetectapp.grabcropcoordrect.origin.x,facedetectapp.grabcropcoordrect.origin.y,facedetectapp.grabcropcoordrect.size.width,facedetectapp.grabcropcoordrect.size.height);
            CGContextStrokeRect(contextRef, face_rect);
            //CGContextFillEllipseInRect(contextRef,face_rect);
            CGContextStrokeEllipseInRect(contextRef,face_rect);

            [pool release];
        }

    }
    CGImageRef imageRef = CGImageCreateWithImageInRect([originalImage CGImage],face_rect);
    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
    CGImageRelease(imageRef);


    CGContextRelease(contextRef);
    CGColorSpaceRelease(colorSpace);

    cvReleaseMemStorage(&storage);
    cvReleaseHaarClassifierCascade(&cascade);

    return returnImage;
}

【讨论】：

【解决方案2】：

看看这篇文章。它包括一个演示项目，并解释了如何在处理实时视频时获得最佳性能。

Computer vision with iOS Part 2: Face tracking in live video

【讨论】：