pbicubicrescale

Performs an affine rescaling of 2D image using the bicubic interpolation.

Synopsis

pbicubicrescale zoomx zoomy zoomyz [im_in|-] [im_out|-]

Description

pbicubicrescale changes magnification of the input image by a factor zoomx along the x axis, zoomy along the y axis and zoomz along the z axis (for 3D images). The image is enlarged along an axis if the zoom factor is > 1 and is shrunk if the zoom factor is >0 and <1.

This version uses the bicubic interpolation. For bicubic interpolation, the output pixel value is a weighted average\ of pixels in the nearest 4-by-4 neighborhood.

This operator needs a long execution time. Thus it can only be used for 2D images. To rescale region map or graph or 3D image, use the operator prescale.

Parameters

zoomx, zoomy, zoomz are positive real values.
if a zoom factor is > 1 then the image is enlarged along the related axis.

if a zoom factor is < 1 then the image is shrunk along the related axis.
zoomz is ignored since this operator only works on 2D images.

Inputs

im_in: an 2D image.

Outputs

im_out: an image of the same type as the input image.

Result

Returns SUCCESS or FAILURE.

Examples

Enlarges the tangram.pan image by a factor 2:

   pbicubicrescale 2 2 0 tangram.pan a.pan

Shrinks the tangram.pan image by a factor 2:

   pbicubicrescale 0.5 0.5 0 tangram.pan a.pan

C++ prototype

Errc PBicubicRescale( const Img2duc &im_in, Img2duc &im_out, float zoomy, float zoomx );

Version française

Augmentation ou réduction de la taille d'une image par interpolation bicubique.

Author: Régis Clouard