Better Luma Denoise
The current methods of luma denoise blur the image too much and destroy too much fine detail compared to other software like Aftershot Pro (noise ninja) and lightroom. They also produce a distracting speckle effect between flat blotches. Eq is better than raw denoise, but both don't appear to be up to modern standards for luma noise reduction.
#1 Updated by Rick Gabriel over 6 years ago
This is becoming more of a problem for me since the quality of exported images is my number one priority. A link to a test album is above. I suggest you download the original full-size images and view at 100%. The file names tell which is which (expand details on the right). I shot this test in RAW+JPG and performed noise reduction with 4 different applications: In-camera JPG (standard noise reduction, faithful profile), Aftershot Pro (which uses NoiseNinja), Darktable (git from today, Eq module used), and Adobe Lightroom 4.2.Take a look at the fine details like the figure's ear and mustache and the color noise in the background. I only used the Equalizer module in darktable and raw denoise. No sharpening or other PP was applied in any application. The results are a bit subjective, but here's my take on them:
- Lightroom produces the cleanest looking image with the best colors. Luma and chroma noise are reduced greatly, but the details are preserved. The final grain pattern looks pleasing. All of this was accomplished in a few seconds by adjusting two sliders. There are a lot of things I don't like about Lightroom, but it's noise reduction seems best.
- NoiseNinja via ASP seems roughly equal to the in-camera JPG. It's a little worse handling chroma noise, but perhaps slightly better with luma. It's relatively quick to adjust the sliders and get an acceptable result. Still, I prefer the in-camera JPG over NoiseNinja by a small margin.
- I'm sorry to say that the Darktable JPG is the worst. When reducing the luma noise to roughly match the camera JPG, many of the details are lost. Chroma noise reduction in DT is adequate but it harms the color details too much. The image colors are not quite accurate either (using either standard or enhanced color matrix); the figure's arms are not neon yellow for example. Lastly, the time required to achieve this is very high compared to the others. Even after creating a slew of Eq presets, I find I have to tweak settings quite a bit depending on the image. When processing 500 images at a time, this adds up significantly.
The biggest disappointment is that Darktable's noise reduction seems worse than the JPG right from the camera. While the Equalizer module is very powerful and flexible, the final image quality isn't up to its competitors and the time required to achieve that result is too long especially for high-ISO images.
I hope this constructive criticism is taken in a positive way. I actually really like Darktable. Your approach is innovative and powerful. I like the speed and "open" mentality. However, some of the features like noise reduction are not up to industry standards yet and some common functions take too much time to complete. Please let me know if there is anything I can do to help. Thanks!
#2 Updated by Sarge Borsch over 2 years ago
Did you try using "profiled denoise" module? https://www.darktable.org/2012/12/profiling-sensor-and-photon-noise/