UIImage를 흑백 이미지로 바꾸기

UIIamge를 흑백으로 바꾸는 방법을 찾다가..
찾은 내용 입니다.
참고 하세요.

-(UIImage*)convertImageBlackAndWhite:(UIImage *)image
{
    CGColorSpaceRef colorSapce = CGColorSpaceCreateDeviceGray();
    CGContextRef context = CGBitmapContextCreate(nil, image.size.width, image.size.height, 8, image.size.width, colorSapce, kCGImageAlphaNone);
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
    CGContextSetShouldAntialias(context, NO);
    CGContextDrawImage(context, CGRectMake(0, 0, image.size.width, image.size.height), [image CGImage]);
   
    CGImageRef bwImage = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSapce);
   
    UIImage *resultImage = [UIImage imageWithCGImage:bwImage];
    CGImageRelease(bwImage);
    return resultImage;
}