title: Output Image gives NULL after applying CIFilter
body: <p>I want to give effects on the image with <code>CIImage framework</code>, and when i set parameters for that the out put image shows blank image.</p>
  
  <p>Any suggestions? </p>
  
  <p>Code is used to apply filter is as  follows :</p>
  
  <pre><code>- (IBAction)filterImage:(id)sender {
  
      CIImage *rawImageData;
      rawImageData =[[CIImage alloc] initWithImage:self.imageView.image];
  
      CIFilter *filter = [CIFilter filterWithName:@"CIDepthOfField"];
      [filter setDefaults];
  
      [filter setValue:rawImageData forKey:@"inputImage"];
  
      [filter setValue:[CIVector vectorWithCGPoint:CGPointMake(50, 50)]
                forKey:@"inputPoint1"];
  
      [filter setValue:[CIVector vectorWithCGPoint:CGPointMake(100, 100)]
                forKey:@"inputPoint2"];
  
      [filter setValue:[NSNumber numberWithFloat:15.00]
                forKey:@"inputSaturation"];    
  
      [filter setValue:[NSNumber numberWithFloat:15.00]
                forKey:@"inputUnsharpMaskRadius"];
  
      [filter setValue:[NSNumber numberWithFloat:15.70]
                forKey:@"inputRadius"];
  
  
  
      CIImage *filteredImageData = [filter valueForKey:@"outputImage"];
  
      UIImage *filteredImage = [UIImage imageWithCIImage:filteredImageData];
      self.imageView.image = filteredImage;
  
  
  }
  </code></pre>