Title :
Soft adaptive gradient angle interpolation of grayscale images
Author :
Zwart, Christine M. ; Frakes, David H.
Author_Institution :
Sch. of Biol. & Health Syst. Eng., Arizona State Univ., Tempe, AZ, USA
Abstract :
We introduce a new edge-directed interpolator based on locally defined, straight line approximations to image isophotes. The first spatial derivatives of image intensity are used to describe the behavior of pixel-intersecting isophotes in terms of their slopes. Slopes are determined by inverting a tridiagonal matrix and are forced to vary linearly from pixel to pixel. Image resizing is performed using standard, 1D interpolators along the approximated isophotes. The proposed method can accommodate arbitrary scaling factors, provides state-of-the-art results in terms of PSNR as well as other quantitative quality metrics, and has the advantage of computational complexity that is directly proportional to the number of pixels.
Keywords :
approximation theory; gradient methods; image colour analysis; interpolation; matrix algebra; 1D interpolator; PSNR; approximated isophotes; arbitrary scaling factor; computational complexity; edge-directed interpolator; grayscale image; image intensity; image isophotes; image resizing; pixel-intersecting isophotes; quantitative quality metrics; slope; soft adaptive gradient angle interpolation; spatial derivatives; straight line approximation; tridiagonal matrix; Complexity theory; Equations; Image edge detection; Interpolation; Mathematical model; Measurement; Vectors; interpolation; least squares methods;
Conference_Titel :
Acoustics, Speech and Signal Processing (ICASSP), 2012 IEEE International Conference on
Conference_Location :
Kyoto
Print_ISBN :
978-1-4673-0045-2
Electronic_ISBN :
1520-6149
DOI :
10.1109/ICASSP.2012.6288016