// NOTE You should convert color mode as RGB before passing to this function
- (UIImage *)UIImageFromIplImage:(IplImage *)image {
  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
  // Allocating the buffer for CGImage
  NSData *data =
    [NSData dataWithBytes:image->imageData length:image->imageSize];
  CGDataProviderRef provider =
    CGDataProviderCreateWithCFData((CFDataRef)data);
  // Creating CGImage from chunk of IplImage
  CGImageRef imageRef = CGImageCreate(
    image->width, image->height,
    image->depth, image->depth * image->nChannels, image->widthStep,
    colorSpace, kCGImageAlphaNone|kCGBitmapByteOrderDefault,
    provider, NULL, false, kCGRenderingIntentDefault
  );
  // Getting UIImage from CGImage
  UIImage *ret = [UIImage imageWithCGImage:imageRef];
  CGImageRelease(imageRef);
  CGDataProviderRelease(provider);
  CGColorSpaceRelease(colorSpace);
  return ret;
}

http://niw.at/articles/2009/03/14/using-opencv-on-iphone/en

UIImage from IplImage

Objective C