Help with training model for noise reduction of darker area lines

[CarbonPool]

For most of the darker images similar to this, I have tried all three-level noise reduction models, and their lines are smeared. What training set is suitable to help preserve these details?

• origin

• default cunet level3 2x

-trained cunet model level3 2x

[nagadomi]

For training data, you can add an image with a narrow range of colors. Another way is to normalize the input image to be minimum 0 and maximum 255, convert it with waifu2x, and then revert the color range.