Camera Filter + Clarity and GPUImage

Question

I play with some camera filters using GPUImage and try to get something similar to the Camera + Clarity filter (not expecting a 100% match, of course, but to get into the same stadium). But I just can not get closer to this effect. Any idea what Clarity does from a conceptual point of view?

Answer 1

This thread contains a good conceptual discussion about the Lux effect on Instagram, which is similar to the Clarity effect on Camera + (if I'm not mistaken).