Luminance Noise Luminance noise, also known as luminance grain or monochromatic noise, refers to random variations in brightness or intensity that appear as unwanted speckles or graininess in digital images. Luminance noise is caused by electronic interference, thermal noise, or sensor limitations during image capture and processing. It is more noticeable in underexposed areas of an image or images captured at high ISO sensitivity settings, where the signal-to-noise ratio is lower.
Luminance noise can degrade image quality, reducing sharpness, detail, and tonal range, particularly in shadow areas and smooth gradients. In post-processing, photographers can use noise reduction techniques and software tools to reduce luminance noise while preserving image detail and clarity. Common noise reduction methods include smoothing algorithms, wavelet denoising, and selective noise reduction targeting specific tonal ranges or color channels. |