GPUImage Binarization in iOS

Question

I am trying to use image Binarization using GPUImage techniques. I wrote these lines of code where is "image" is greyscale image

 GPUImagePicture *imageSource = [[GPUImagePicture alloc] initWithImage:image];
 GPUImageAdaptiveThresholdFilter *stillImageFilter = [[GPUImageAdaptiveThresholdFilter alloc] 
 init];
 stillImageFilter.blurRadiusInPixels = 3.0;
 [imageSource addTarget:stillImageFilter];
 [imageSource useNextFrameForImageCapture];
 [imageSource processImage];
 UIImage *retImage = [stillImageFilter imageFromCurrentFramebuffer];

I am getting "Nil" as retImage. I can't figure out my mistake. Anybody help me?

Answer 1

You need to call -useNextFrameForImageCapture on stillImageFilter, not imageSource.