Denoise

Noise is a serious problem that hinders high quality digital image processing. In digital photography, the consumer- and prosumer-level cameras produce images with an easy noticeable noise component. This component is especially strong in images which are taken at high ISO rates. The noise reduces the visual quality of digital images and resulting printouts. Some image processing operations, like sharpening, make a quality of the noisy images even worse.

Denoise is a digital filter designed to reduce a visible noise in digital photos.

The user can adjust many parameters for this filter. Luminance and color strength make it possible to specify noise reducing strength (in percents) in luminance and color channels correspondingly. Threshold parameter helps to select noise from the image. Higher values of this parameter leave more noise in the image, lower values produce blured image. Area radius specifies radius for the noise analysis. Higher values allow to reduce low frequency noise but this can blur the image. Area smoothing parameter let the user set the smoothing factor for uniform regions (non edge regions). Sharpness parameter sets amount of edge sharpening in percents, higher values can leave some noise in image. Image details parameter allows to specify how many small details must be leaved after the denoise. Lower values produce blured image, higher values can leave image noisy. The number of iterations can be specified through the corresponding slider. The user should be careful with this parameter, as the filter takes a lot of time for processing.

To use the Denoise filter:

Choose Image > Restoration > Denoise