vignetting

n.

a brief literary description

同义词：sketch

a photograph whose edges shade off gradually

a small illustrative sketch (as sometimes placed at the beginning of chapters in books)

Single-image vignetting correction
Single-Image Vignetting Correction
Practical anti-vignetting methods for digital cameras
Vignetting Distortion Correction Method for High Quality Digital Imaging
On cosine-fourth and vignetting effects in real lenses
Single-image vignetting correction using radial gradient symmetry
Robust Radiometric Calibration and Vignetting Correction
Apparatus and method for excluding vignetting in a digital camera
Correction of uneven illumination (vignetting) in digital microscopy images
Wavenumber Scale Shift in Fourier Transform Infrared Spectrometers Due to Vignetting