OpenCV视频处理教程问题

Question

我按照OpenCV网站上的iOS视频处理教程进行了编译并安装在设备上。然而，当我点击"开始"按钮时，什么也看不见。显然，我的- (void)processImage:(Mat&)image回调从未被调用。你能给我提示一下是什么问题吗?

Some things I check:

调用
• actionStart，并且两条日志行都打印YES
• self对象在分配给self.videoCamera.delegate时有效
• imageView有效且在屏幕上可见
• videoCamera在start方法被调用时被初始化

我用iPhone 3GS进行测试。

这是我的ViewController.h的完整源代码:

#import <UIKit/UIKit.h>
#import <opencv2/highgui/cap_ios.h>
@interface ViewController : UIViewController <CvVideoCameraDelegate>
{
    IBOutlet UIImageView* imageView;
    IBOutlet UIButton* button;
    CvVideoCamera* videoCamera;
}
- (IBAction)actionStart:(id)sender;
@property (nonatomic, strong) CvVideoCamera* videoCamera;
@end

和ViewController.mm:

@implementation ViewController
@synthesize videoCamera;
- (void)viewDidLoad
{
    [super viewDidLoad];
    self.videoCamera = [[CvVideoCamera alloc] initWithParentView:imageView];
    self.videoCamera.delegate = self;
    self.videoCamera.defaultAVCaptureDevicePosition = AVCaptureDevicePositionFront;
    self.videoCamera.defaultAVCaptureSessionPreset = AVCaptureSessionPreset352x288;
    self.videoCamera.defaultAVCaptureVideoOrientation = AVCaptureVideoOrientationPortrait;
    self.videoCamera.defaultFPS = 30;
    self.videoCamera.grayscaleMode = NO;
}
#pragma mark - UI Actions
- (IBAction)actionStart:(id)sender;
{
    [self.videoCamera start];
    NSLog(@"video camera running: %d", [self.videoCamera running]);
    NSLog(@"capture session loaded: %d", [self.videoCamera captureSessionLoaded]);
}
#pragma mark - Protocol CvVideoCameraDelegate
- (void)processImage:(cv::Mat&)image
{
    // Do some OpenCV stuff with the image
    cv::Mat image_copy;
    cvtColor(image, image_copy, CV_BGRA2BGR);
    // invert image
    bitwise_not(image_copy, image_copy);
    cvtColor(image_copy, image, CV_BGR2BGRA);
}
@end

Answer 1

我在iPhone 4上测试过，效果不错。也许iPhone 3GS没有前置摄像头?然后你必须改变这一行:self.videoCamera.defaultAVCaptureDevicePosition = AVCaptureDevicePositionFront到self.videoCamera.defaultAVCaptureDevicePosition = AVCaptureDevicePositionBack