Kuvanparannus

Kuvanparannus, or image enhancement, refers to the process of improving a picture's quality or readability by adjusting visual properties such as brightness, contrast, color, sharpness, and noise. The term is used in Finnish to describe both traditional and digital techniques applied to photographs, scans, and other images. The goal is not to create new information but to render the image more faithful to the scene or more suitable for its purpose.

Techniques range from analog methods used in the darkroom—dodging, burning, toning—and to modern digital processing, which can be performed with software on single images or sequences.

Digital methods include noise reduction, histogram-based contrast adjustment, gamma correction, sharpening (unsharp masking), deconvolution, restoration of faded colors, alignment and stabilization, and, more recently, machine-learning-based enhancement and super-resolution.

Applications include enhancing personal photos, restoring archival photographs, improving video and surveillance footage, medical imaging, astronomy, and satellite imagery.

Challenges include the risk of introducing artifacts, over-processing, or amplifying noise; evaluation is done with objective measures such as PSNR and SSIM and with subjective assessment.

Related topics include image restoration and digital image processing.