Oskarphet

Oskarphet is a Swedish term meaning lack of sharpness or blur, used in optics, photography, imaging and vision to describe loss of fine detail and edge definition. It can refer to visual perception as well as measurable properties of images and optical systems.

Causes of oskarphet include defocus (incorrect focal plane), motion blur from relative movement during exposure, optical aberrations in lenses, diffraction limits at small apertures, atmospheric turbulence for long-distance imaging, sensor noise and digital compression artifacts. In human vision, refractive errors (myopia, hyperopia), cataracts and other ocular conditions produce perceived oskarphet.

Technical descriptions often use the point spread function (PSF) and modulation transfer function (MTF) to quantify how an imaging system spreads and attenuates detail. Common models of blur include Gaussian and uniform (box) kernels for defocus and linear kernels for motion. Measured quantities include blur radius and contrast loss at given spatial frequencies.

Mitigation strategies span hardware and software approaches. Optically, improving lens quality, adjusting aperture, increasing exposure speed or stabilizing the camera reduce blur. Computational methods include deconvolution, sharpening filters, multi-frame reconstruction and modern machine-learning–based deblurring and super-resolution. In clinical settings, eyeglasses, contact lenses and surgery address medically caused oskarphet.

Oskarphet can also be used intentionally for artistic effect, controlling depth of field or conveying motion. Its management is central to photography, microscopy, astronomy, medical imaging and computer vision.