PRIME (Probabilistic Raw IMage Enhancement) noise reduction technology reduces noise even at very high sensitivities, while preserving the details, textures, and colors — even in shadowed areas.
This technology is based on an algorithm that searches for similarities among pixels, whose values are then averaged. As the challenge is to preserve textures and details, PRIME averages only those pixels presenting self-similarities. To find them, the algorithm defines a large search area in which at least 1,000 candidate pixels are tested for each pixel!
Two steps are necessary for this operation: a first "oracle" step that identifies the similarities within RAW files, and then, returning to the original image, a second denoising step that is based on the previously-identified similarities.
This denoising requires a large number of calculations. It might take several minutes, for example, to process a 20 Mpix image, but this extraordinary denoising takes place in the background without requiring any intervention on your part!
DxO Optics Pro lets you obtain images of excellent quality even at extreme sensitivities. For example, a photo taken at 51,200 ISO denoised with PRIME is comparable to an undenoised image shot at 3200 ISO: you gain 4 stops!