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Having trouble creating UIImage from CIImage in iOS5

I'm using the AVFoundation framework. In my sample buffer delegate I have the following code:

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
     CVPixelBufferRef pb = CMSampleBufferGetImageBuffer(sampleBuffer);
     CIImage *ciImage = [CIImage imageWithCVPixelBuffer:pb];
     self.imageView.image = [UIImage imageWithCIImage:ciImage];
}

I am able to use the CIImage to run the face detector etc. but it does not show up in the UIImageView ... the imageView remains white. Any ideas as to the problem? I am using the following to setup my session:

    self.session = [[AVCaptureSession alloc] init];
self.session.sessionPreset = AVCaptureSessionPreset640x480;
self.videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
self.videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil]; 
self.frameOutput = [[AVCaptureVideoDataOutput alloc] init];
self.frameOutput.videoSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
like image 576
user491880 Avatar asked Oct 17 '11 00:10

user491880


3 Answers

This might help. I was having the same issue (image not being drawn to screen) with this code:

CIImage *image = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"mushroom.jpg"]];

theImageView.image = [UIImage imageWithCIImage:image];

However, after changing the code to this, it now works correctly:

CIImage *image = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"mushroom.jpg"]];

CIContext *context = [CIContext contextWithOptions:nil];

theImageView.image = [UIImage imageWithCGImage:[context createCGImage:image fromRect:image.extent]];

To read more about CIContext take a look here: http://developer.apple.com/library/ios/#DOCUMENTATION/GraphicsImaging/Reference/QuartzCoreFramework/Classes/CIContext_Class/Reference/Reference.html#//apple_ref/occ/cl/CIContext

like image 167
spybart Avatar answered Nov 17 '22 04:11

spybart


Here is one way that I got it to work:

CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef ref = [context createCGImage:result fromRect:ciImage.extent];
self.imgView.image = [UIImage imageWithCGImage:ref scale:1.0 orientation:UIImageOrientationRight];
CGImageRelease(ref);

Note: Creating the context multiple times is really bad and actually causes a memory leak. You should just create the context once as a property in your class instance and reuse it!

like image 42
user491880 Avatar answered Nov 17 '22 04:11

user491880


CIImage *ciImage = [UIImage imageNamed:@"imageName.png"].CIImage;
UIImage *uiImage = [[UIImage alloc] initWithCIImage:ciImage];
like image 3
sathiamoorthy Avatar answered Nov 17 '22 03:11

sathiamoorthy