avir::CImageResizerParamsUltra Struct Reference

Set of resizing algorithm parameters for ultra low-aliasing resizing (13.68/1.79/1.000(521792.07)/0.000026). More...

#include <avir.h>

Inheritance diagram for avir::CImageResizerParamsUltra:

Additional Inherited Members
Public Attributes inherited from avir::CImageResizerParams
double	CorrFltAlpha
	Alpha parameter of the Peaked Cosine window function used on the correction filter. The "usable" values are in the narrow range 1.0 to 1.5.
double	CorrFltLen
	Correction filter's length in samples (taps). The "usable" range is narrow, 5.5 to 8, as to minimize the "overcorrection" which is mathematically precise, but visually unacceptable.
double	HBFltAlpha
	Half-band filter's Alpha. Assigned internally.
double	HBFltCutoff
	Half-band filter's cutoff point [0; 1]. Assigned internally.
double	HBFltLen
	Length of the half-band low-pass filter. Assigned internally. Internally used to perform 2X or higher downsampling. These filter parameters should be treated as "technical" and do not require adjustment as they were tuned to suit all combinations of other parameters. This half-band filter provides a wide transition band (for minimal ringing artifacts) and a high stop-band attenuation (for minimal aliasing).
double	IntFltAlpha
	Alpha parameter of the Peaked Cosine window function used on the interpolation low-pass filter. The "usable" values are in the range 1.5 to 2.5.
double	IntFltCutoff
	Interpolation low-pass filter's cutoff frequency (normalized, [0; 1]). The "usable" range is 0.6 to 0.8.
double	IntFltLen
	Interpolation low-pass filter's length in samples (taps). The length value should be at least 18 or otherwise a "dark grid" artifact will be introduced if a further sharpening is applied. IntFltLen together with other IntFlt parameters should be tuned in a way that produces the flattest frequency response in 0-0.5 normalized frequency range (this range is due to 2X upsampling).
double	LPFltAlpha
	Alpha parameter of the Peaked Cosine window function used on the low-pass filter. The "usable" values are in the range 1.5 to 6.5.
double	LPFltBaseLen
	Base length of the low-pass (aka anti-aliasing or reconstruction) filter, in samples (taps), further adjusted by the actual cutoff frequency, upsampling and downsampling factors. The "usable" range is between 6 and 9.
double	LPFltCutoffMult
	Low-pass filter's cutoff frequency multiplier. This value can be both below and above 1.0 as low-pass filters are inserted on downsampling and upsampling steps and always have corner frequency equal to or below 0.5pi. This multiplier shifts low-pass filter's corner frequency towards lower (if below 1.0) or higher (if above 1.0) frequencies. This multiplier can be way below 1.0 since any additional high-frequency damping will be partially corrected by the correction filter. The "usable" range is 0.3 to 1.0.

Detailed Description

Set of resizing algorithm parameters for ultra low-aliasing resizing (13.68/1.79/1.000(521792.07)/0.000026).

This set of resizing algorithm parameters offers a very considerable anti-aliasing performance with a good frequency response linearity (and contrast). This set of parameters is computationally expensive and may produce ringing artifacts on sharp features.