Target Images

[zchen002]

Hi, I'm a bit confused, what is the purpose of target images? are target images same as source images?

[yu4u]

In general denoising problems, noisy images and clean images are used for inputs and targets respectively in training. In noise2noise model, both inputs and targets are noisy images, which are the same image with different noises.

[zchen002]

I got it now, thanks for answering.

[tangsipeng]

sorry,i still don't understand. how can i have one image that have different noises. unless i have a clean image that i can produce different noises

[yu4u]

You might take pictures of a static scene (e.g. very dark scene). Simply by doing so, you can get different noise images sharing unknown clean image. The other assumed examples can be found in the original paper.

[tangsipeng]

thank you, i got it

[AllenJac]

If we have one real image with different level random noise, we don't need to add Gaussian noise with zero-mean. How could we make sure the expectation unchanged, or the expectation is the clean image?

[yu4u]

In real use cases, we cannot know exact noise generation process, and thus we cannot make sure the expectation becomes a clean image. Simply we can infer what kind of statistics can be used and try it.