GPUImage – 如何用GPUImagePicture链接filter？

我想要在GPUImage FilterShowcase中的“哈里斯angular检测”，但与GPUImagePicture而不是GPUImageVideoCamera实现相同的效果。

我不能让filter链工作。 这是我现在的代码：

 -(UIImage*)addHarrisCornerToImage:(UIImage*)inputImage { GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:inputImage]; GPUImageHarrisCornerDetectionFilter *cornerDetectionFilter = [[GPUImageHarrisCornerDetectionFilter alloc] init]; [(GPUImageHarrisCornerDetectionFilter *)_filter setThreshold:0.20]; GPUImageCrosshairGenerator *crosshairGenerator = [[GPUImageCrosshairGenerator alloc] init]; crosshairGenerator.crosshairWidth = 15.0; [crosshairGenerator forceProcessingAtSize:CGSizeMake(480.0, 640.0)]; [(GPUImageHarrisCornerDetectionFilter *)_filter setCornersDetectedBlock:^(GLfloat* cornerArray, NSUInteger cornersDetected, CMTime frameTime) { [crosshairGenerator renderCrosshairsFromArray:cornerArray count:cornersDetected frameTime:frameTime]; }]; GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init]; [blendFilter forceProcessingAtSize:CGSizeMake(480.0, 640.0)]; GPUImageGammaFilter *gammaFilter = [[GPUImageGammaFilter alloc] init]; [stillImageSource addTarget:gammaFilter]; [gammaFilter addTarget:blendFilter]; [crosshairGenerator addTarget:blendFilter]; GPUImagePicture *crosshairImageSource = [[GPUImagePicture alloc] initWithImage:[crosshairGenerator imageFromCurrentlyProcessedOutput]]; [crosshairImageSource addTarget:cornerDetectionFilter]; [stillImageSource addTarget:cornerDetectionFilter]; [stillImageSource processImage]; UIImage *imageWithCorners = [cornerDetectionFilter imageFromCurrentlyProcessedOutput]; return imageWithCorners; } 

如果我使用video源作为源，它工作正常，它看起来像这样：

 -(void)addHarrisCorner { _videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack]; _videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait; GPUImageView *filteredVideoView = [[GPUImageView alloc] initWithFrame:CGRectMake(10, 150, 300, 300)]; _filter = [[GPUImageHarrisCornerDetectionFilter alloc] init]; [(GPUImageHarrisCornerDetectionFilter *)_filter setThreshold:0.20]; GPUImageCrosshairGenerator *crosshairGenerator = [[GPUImageCrosshairGenerator alloc] init]; crosshairGenerator.crosshairWidth = 15.0; [crosshairGenerator forceProcessingAtSize:CGSizeMake(480.0, 640.0)]; [(GPUImageHarrisCornerDetectionFilter *)_filter setCornersDetectedBlock:^(GLfloat* cornerArray, NSUInteger cornersDetected, CMTime frameTime) { [crosshairGenerator renderCrosshairsFromArray:cornerArray count:cornersDetected frameTime:frameTime]; }]; GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init]; [blendFilter forceProcessingAtSize:CGSizeMake(480.0, 640.0)]; GPUImageGammaFilter *gammaFilter = [[GPUImageGammaFilter alloc] init]; [_videoCamera addTarget:gammaFilter]; [gammaFilter addTarget:blendFilter]; [crosshairGenerator addTarget:blendFilter]; [blendFilter addTarget:filteredVideoView]; [_videoCamera addTarget:_filter]; [_filter addTarget:filteredVideoView]; [_videoCamera startCameraCapture]; [[self view] addSubview:filteredVideoView]; } 

我真的不知道GPUImagePicture *crosshairImageSource = [[GPUImagePicture alloc] initWithImage:[crosshairGenerator imageFromCurrentlyProcessedOutput]]; 和/或如果我应该使用[stillImageSource processImage]; 我添加每个filter后。

有人能指出我正确的方向吗？

谢谢

*更新*

通过查看GPUImage文件夹中的FeatureExtractionTest，我设法使它工作一些，但它没有find任何angular落。 输出是Number of corners: 0 。 我一直玩的threshold ， sensitivity和blurSize值。

这是新的代码：

 - (void)testCornerDetectorWithPicture:(UIImage *)image { // GPUImagePicture *pictureInput = [[GPUImagePicture alloc] initWithImage:image]; GPUImagePicture *pictureInput = [[GPUImagePicture alloc] initWithImage:[UIImage imageNamed:@"testCorner.png"]]; _harrisCornerFilter = [[GPUImageHarrisCornerDetectionFilter alloc] init]; _harrisCornerFilter.threshold = 0.2; _harrisCornerFilter.sensitivity = 5.0; _harrisCornerFilter.blurSize = 1.0; [pictureInput removeAllTargets]; [pictureInput addTarget:_harrisCornerFilter]; __weak typeof(self) weakSelf = self; [_harrisCornerFilter setCornersDetectedBlock:^(GLfloat* cornerArray, NSUInteger cornersDetected, CMTime frameTime) { GPUImageCrosshairGenerator *crosshairGenerator = [[GPUImageCrosshairGenerator alloc] init]; crosshairGenerator.crosshairWidth = 10.0; [crosshairGenerator setCrosshairColorRed:1.0 green:0.0 blue:0.0]; [crosshairGenerator forceProcessingAtSize:[pictureInput outputImageSize]]; GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init]; [blendFilter forceProcessingAtSize:[pictureInput outputImageSize]]; [pictureInput addTarget:blendFilter]; [crosshairGenerator addTarget:blendFilter]; [blendFilter prepareForImageCapture]; NSLog(@"Number of corners: %d", cornersDetected); [crosshairGenerator renderCrosshairsFromArray:cornerArray count:cornersDetected frameTime:frameTime]; dispatch_async(dispatch_get_main_queue(), ^{ UIImage *crosshairResult = [blendFilter imageFromCurrentlyProcessedOutput]; [weakSelf useImageWithCornersWithImage:crosshairResult]; }); }]; [pictureInput processImage]; } 

这是我使用的testing图像：

*更新2 *这似乎是一个iOS7的问题。 pipe理让我的代码在iOS6设备上工作。 将进一步调查。

*更新3 *这确实是使用iOS7时的一个错误。 这里提交： https ： //github.com/BradLarson/GPUImage/issues/1205