GPUImageToneCurveFilter not providing filtered/effected image

[SrikanthKabadi]

Hi. I am using GPUImageToneCurveFilter to add Curve tone for R, G and B. This is what I am doing, but I am not getting the filtered/effected image. The image remains original. Where am I going wrong?

#define ZeroToOneScale(x) x/255.0f

GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:mainImageView.image];
GPUImageToneCurveFilter *stillImageFilter = [[GPUImageToneCurveFilter alloc] init];

[stillImageSource addTarget:stillImageFilter];

[stillImageFilter setRedControlPoints:[NSArray arrayWithObjects:
                                      [NSValue valueWithCGPoint:CGPointMake(0.0, 0.0)],
                                      [NSValue valueWithCGPoint:CGPointMake(0.125, 0.25)],
                                      [NSValue valueWithCGPoint:CGPointMake(0.5, 0.5)],
                                      [NSValue valueWithCGPoint:CGPointMake(0.75, 0.675)],
                                      [NSValue valueWithCGPoint:CGPointMake(0.875, 0.75)],
                                      [NSValue valueWithCGPoint:CGPointMake(1.0, 1.0)],
                                      nil]];

[stillImageFilter setRedControlPoints:[NSArray arrayWithObjects:[NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(0), ZeroToOneScale(23))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(133), ZeroToOneScale(138))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(209), ZeroToOneScale(227))] , [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(254), ZeroToOneScale(227))], nil]];

[stillImageFilter setGreenControlPoints:[NSArray arrayWithObjects:[NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(0), ZeroToOneScale(59))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(33), ZeroToOneScale(59))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(166), ZeroToOneScale(170))] , [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(220), ZeroToOneScale(234))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(255), ZeroToOneScale(234))], nil]];

[stillImageFilter setBlueControlPoints:[NSArray arrayWithObjects:[NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(0), ZeroToOneScale(3))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(20), ZeroToOneScale(3))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(129), ZeroToOneScale(123))] , [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(189), ZeroToOneScale(216))], nil]];

[stillImageSource processImage];

[mainImageView setImage:[stillImageFilter imageFromCurrentlyProcessedOutput]];

But if I use this code to apply effect for Red, I get filtered/effected image.

[stillImageFilter setRedControlPoints:[NSArray arrayWithObjects:[NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(0), ZeroToOneScale(23))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(133), ZeroToOneScale(138))], [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(209), ZeroToOneScale(227))] , [NSValue valueWithCGPoint:CGPointMake(ZeroToOneScale(254), ZeroToOneScale(227))], nil]];

[BradLarson]

As you can tell from the many issues here about it, there are problems with the tone curve filter. I have some code that might fix some of this, but I'll only be able to look at it this weekend.

[nostef]

The image remains unchanged because the end points are not 1, specifically 255/255.

[SrikanthKabadi]

Actually the issue was with #define ZeroToOneScale(x) x/255.0f This returns the float value with more than 2 decimal points. Then manually converted to 2 decimal places and executed the same code. It worked. But I am not getting expected result. Program image Output differs from actual output from Adobe Photoshop.

[SrikanthKabadi]

@BradLarson Thank you so much.

[nostef]

The decimal points aren't an issue. I regularly send data as '(int between 0-255) / 255.0f) and it works fine. Something else must be the problem in your code. Specifically what for sure is a problem is that you didn't add the ending point.

The end point must be CGPointMake(1, (float between 0-1)).

[nostef]

Paste your code, your desired output and the GPUImage tone curve output.

[SrikanthKabadi]

@nostef This is my code.

GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:originalImage smoothlyScaleOutput:YES];
GPUImageToneCurveFilter *stillImageFilter = [[GPUImageToneCurveFilter alloc] init];
[stillImageSource addTarget:stillImageFilter];
[stillImageFilter setRedControlPoints:
 [NSArray arrayWithObjects: 
  [NSValue valueWithCGPoint:[self createPointArray:0 yvalue:23]],
  [NSValue valueWithCGPoint:[self createPointArray:113 yvalue:138]],
  [NSValue valueWithCGPoint:[self createPointArray:209 yvalue:227]],
  [NSValue valueWithCGPoint:[self createPointArray:254 yvalue:227]],
  nil]];

[stillImageFilter setGreenControlPoints:
 [NSArray arrayWithObjects: 
  [NSValue valueWithCGPoint:[self createPointArray:0 yvalue:59]],
  [NSValue valueWithCGPoint:[self createPointArray:33 yvalue:59]],
  [NSValue valueWithCGPoint:[self createPointArray:166 yvalue:170]],
  [NSValue valueWithCGPoint:[self createPointArray:222 yvalue:234]],
  [NSValue valueWithCGPoint:[self createPointArray:255 yvalue:234]],
  nil]];

[stillImageFilter setBlueControlPoints:
 [NSArray arrayWithObjects: 
  [NSValue valueWithCGPoint:[self createPointArray:0 yvalue:3]],
  [NSValue valueWithCGPoint:[self createPointArray:20 yvalue:3]],
  [NSValue valueWithCGPoint:[self createPointArray:129 yvalue:123]],
  [NSValue valueWithCGPoint:[self createPointArray:189 yvalue:216]],
  nil]];

[stillImageSource processImage];
[mainImageView setImage:[stillImageFilter imageFromCurrentlyProcessedOutput]];

[stillImageSource release];
[stillImageFilter release];

Desired output is http://dl.dropbox.com/u/14661827/For%20Test/Desired.png

GPUimage tone curve output is http://dl.dropbox.com/u/14661827/For%20Test/GPUImage%20output.png

[nostef]

Start by adding to both BlueControlPoints and RedControlPoints the last 255 x point.

eg: [stillImageFilter setBlueControlPoints: [NSArray arrayWithObjects: [NSValue valueWithCGPoint:[self createPointArray:0 yvalue:3]], [NSValue valueWithCGPoint:[self createPointArray:20 yvalue:3]], [NSValue valueWithCGPoint:[self createPointArray:129 yvalue:123]], [NSValue valueWithCGPoint:[self createPointArray:189 yvalue:216]], [NSValue valueWithCGPoint:[self createPointArray:255 yvalue:255]], nil]];

[SrikanthKabadi]

By doing this, its becoming much worse. You can see the result here. http://dl.dropbox.com/u/14661827/For%20Test/New%20Result.png