80 

    81 -(UIImage *)convertImageToGrayScale:(UIImage *)image {

    82   // Create image rectangle with current image width/height

    83   CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height);

    84  

    85   // Grayscale color space

    86   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

    87  

    88   // Create bitmap content with current image size and grayscale colorspace

    89   CGContextRef context = CGBitmapContextCreate(nil, image.size.width, image.size.height, 8, 0, colorSpace, kCGImageAlphaNone);

    90  

    91   // Draw image into current context, with specified rectangle

    92   // using previously defined context (with grayscale colorspace)

    93   CGContextDrawImage(context, imageRect, [image CGImage]);

    94  

    95   // Create bitmap image info from pixel data in current context

    96   CGImageRef imageRef = CGBitmapContextCreateImage(context);

    97  

    98   // Create a new UIImage object  

    99   UIImage *newImage = [UIImage imageWithCGImage:imageRef];

   100  

   101   // Release colorspace, context and bitmap information

   102   CGColorSpaceRelease(colorSpace);

   103   CGContextRelease(context);

   104   CFRelease(imageRef);

   105  

   106   // Return the new grayscale image

   107   return newImage;

   108 }