iOS - Cannot process image using CIFilter - iphone

Question

I am trying to process image using Core Image. I have created UIImage category to do it.
I have added QuartzCore and CoreImage frameworks to project, imported CoreImage/CoreImage.h and used this code:
CIImage *inputImage = self.CIImage;
CIFilter *exposureAdjustmentFilter = [CIFilter filterWithName:#"CIExposureAdjust"];
[exposureAdjustmentFilter setDefaults];
[exposureAdjustmentFilter setValue:inputImage forKey:#"inputImage"];
[exposureAdjustmentFilter setValue:[NSNumber numberWithFloat:5.0f] forKey:#"inputEV"];
CIImage *outputImage = [exposureAdjustmentFilter valueForKey:#"outputImage"];
CIContext *myContext = [CIContext contextWithOptions:nil];
return [UIImage imageWithCGImage:[myContext createCGImage:outputImage fromRect:outputImage.extent]];
But I have got nil output image from the filter.
I have also tried to use CIHueAdjust with the same result.
Than you in advance
UPDATE: I have found solution. It was necessary to alloc new CIImage, not only pass reference to UIImage.CIImage this way:
CIImage *inputImage = [[CIImage alloc] initWithImage:self];

Answer 1

Try following code:-
CIImage *inputImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:#"old-country-rain.jpg"]];
CIFilter * controlsFilter = [CIFilter filterWithName:#"CIExposureAdjust"];
[controlsFilter setValue:inputImage forKey:kCIInputImageKey];
[controlsFilter setValue:[NSNumber numberWithFloat: 2.0f] forKey:#"inputEV"];
NSLog(#"%#",controlsFilter.attributes);
CIImage *displayImage = controlsFilter.outputImage;
UIImage *finalImage = [UIImage imageWithCIImage:displayImage];
CIContext *context = [CIContext contextWithOptions:nil];
if (displayImage == nil || finalImage == nil) {
// We did not get output image. Let's display the original image itself.
imageView.image = [UIImage imageNamed:#"old-country-rain.jpg"];
}else {
// We got output image. Display it.
imageView.image = [UIImage imageWithCGImage:[context createCGImage:displayImage fromRect:displayImage.extent]];
}