Nyquist limit
Definition
The sampling theorem's constraint: to faithfully record a feature, the sensor must sample it at least twice per cycle. A feature smaller than two pixels is aliased or lost entirely. There is no software recovery for sub-Nyquist detail.
Related terms
- CLAHE
- Contrast Limited Adaptive Histogram Equalisation. Divides the image into local tiles, equalises each tile's contrast separately, and blends results. Recovers shadow detail...
- Deconvolution
- A computational technique that estimates the PSF and inverts its effect to recover a sharper image. The quality depends entirely on how...
- Point spread function (PSF)
- A mathematical description of how the imaging system spreads the light from a single point source across neighbouring pixels. Defocus, diffraction, and...
- Spatial resolution
- The finest detail a camera system can record, determined by pixel size and lens quality, measured in line pairs per millimetre or...
- Super-resolution
- Methods that attempt to produce an image with higher pixel density than the source. Interpolation-based SR fills in values by estimation; learning-based...
Explained in
- Image Enhancement: Principles and the Resolution BarrierThe sampling theorem's constraint: to faithfully record a feature, the sensor must sample it at least twice per cycle. A feature smaller than two pixels is ali...