; docformat = 'rst' ; ; NAME: ; FSC_Resize_Image ; ; PURPOSE: ; Provides a CONGRID like resizing of images, although it performs this service ; correctly for both 2D and 3D images. Pixel locations do not change in the output ; image, since the center of the pixel is used for interpolation purposes, rather than ; the lower-left corner of the pixel. Unlike CONGRID, 3D images can use nearest neighbor ; interpolation as well as bilinear interpolation. ; ;******************************************************************************************; ; ; ; Copyright (c) 2010, by Fanning Software Consulting, Inc. All rights reserved. ; ; ; ; Redistribution and use in source and binary forms, with or without ; ; modification, are permitted provided that the following conditions are met: ; ; ; ; * Redistributions of source code must retain the above copyright ; ; notice, this list of conditions and the following disclaimer. ; ; * Redistributions in binary form must reproduce the above copyright ; ; notice, this list of conditions and the following disclaimer in the ; ; documentation and/or other materials provided with the distribution. ; ; * Neither the name of Fanning Software Consulting, Inc. nor the names of its ; ; contributors may be used to endorse or promote products derived from this ; ; software without specific prior written permission. ; ; ; ; THIS SOFTWARE IS PROVIDED BY FANNING SOFTWARE CONSULTING, INC. ''AS IS'' AND ANY ; ; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES ; ; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT ; ; SHALL FANNING SOFTWARE CONSULTING, INC. BE LIABLE FOR ANY DIRECT, INDIRECT, ; ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED ; ; TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; ; ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ; ; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ; ; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ; ; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ; ;******************************************************************************************; ; ;+ ; :Description: ; Provides a CONGRID like resizing of images, although it performs this service ; correctly for both 2D and 3D images. Pixel locations do not change in the output ; image, since the center of the pixel is used for interpolation purposes, rather than ; the lower-left corner of the pixel. Unlike CONGRID, 3D images can use nearest neighbor ; interpolation as well as bilinear interpolation. ; ; :Categories: ; Utilities ; ; :Params: ; image: in, required, type=any ; The image variable to resize. Must be a 2D or 3D image. If a 3D image, ; one of the image dimensions must be a 3. ; ; cols: in, required, type=integer ; The number of columns (i.e., XSIZE) in the output image. ; ; rows: in, required, type=integer ; The number of rows (i.e., YSIZE) in the output image. ; ; :Keywords: ; interpolate: in, optional, type=boolean, default=0 ; Is set, bilinear interpolation is used to resize the image. Otherwise, ; nearest neighbor sampling is used instead. ; minus_one: in, optional, type=boolean, default=0 ; Identical to CONGRID MINUS_ONE keyword. ; ; :Examples: ; Used in a similar fashion to the Congrid command, but for images:: ; IDL> bigEarth = FSC_Resize_Image(cgDemoData(7), 720, 720) ; IDL> bigRose = FSC_Resize_Image(cgDemoData(16), 681, 447) ; ; :Author: ; FANNING SOFTWARE CONSULTING:: ; David W. Fanning ; 1645 Sheely Drive ; Fort Collins, CO 80526 USA ; Phone: 970-221-0438 ; E-mail: david@idlcoyote.com ; Coyote's Guide to IDL Programming: http://www.idlcoyote.com ; ; :History: ; Change History:: ; Written, 20 November 2010. DWF. ; I have been convinced (conversations with Wayne Landsman) that if the ; CENTER keyword is set, the MINUS_ONE keyword is not needed, since ; it was created to solve the same problem. So, I have changed the ; default setting of MINUS_ONE to 0. 11 Jan 2011. DWF. ; Retired and renamed cgResizeImage. 20 Oct 2012. DWF. ; ; :Copyright: ; Copyright (c) 2010, Fanning Software Consulting, Inc. ;- FUNCTION FSC_Resize_Image, image, cols, rows, $ INTERPOLATE=interp, $ MINUS_ONE=minus_one Compile_Opt idl2 ; Check parameters. IF N_Params() EQ 0 THEN BEGIN Print, 'USE SYNTAX: FSC_Resize_Image, image, cols, rows' RETURN, "FSC_Resize_Image Syntax Error" ENDIF ; Return to the caller on an error. On_Error, 2 ; Check image parameter for size. Only 2D and 3D images allowed. ndim = SIZE(image, /N_DIMENSIONS) dims = SIZE(image, /DIMENSIONS) IF ((ndim LT 2) OR (ndim GT 3)) THEN $ Message, 'Input image must have two or three dimensions.' ; Check for keywords. Default for minus_one is 0. interp = Keyword_Set(interp) IF N_Elements(minus_one) EQ 0 THEN minus_one = 0 m1 = Keyword_Set(minus_one) ; 2D images are immediately passed to IDL's Congrid command, with ; the CENTER keyword set. IF ndim EQ 2 THEN BEGIN RETURN, Congrid(image, cols, rows, CENTER=1, MINUS_ONE=minus_one, $ INTERP=interp) ENDIF ; 24-bit images are handled differently. The "3" dimension of a 24-bit ; image should not be interpolated. offset = 0.5 ; To center the pixel location (i.e., CENTER=1 for Congrid) index3 = Where(dims EQ 3) CASE index3 OF 0: BEGIN srx = [0,1,2] sry = Float(dims[1] - m1) / (cols - m1) *(Findgen(cols) + offset) - offset srz = Float(dims[2] - m1) / (rows - m1) *(Findgen(rows) + offset) - offset END 1: BEGIN srx = Float(dims[0] - m1) / (cols - m1) *(Findgen(cols) + offset) - offset sry = [0,1,2] srz = Float(dims[2] - m1) / (rows - m1) *(Findgen(rows) + offset) - offset END 2: BEGIN srx = Float(dims[0] - m1) / (cols - m1) *(Findgen(cols) + offset) - offset sry = Float(dims[1] - m1) / (rows - m1) *(Findgen(rows) + offset) - offset srz = [0,1,2] END ENDCASE ; Do the interpolation. Preserve nearest neighbor sampling, if required. IF interp THEN BEGIN RETURN, Interpolate(image, srx, sry, srz, /GRID) ENDIF ELSE BEGIN RETURN, Interpolate(image, Round(srx), Round(sry), Round(srz), /GRID) ENDELSE END ;--------------------------------------------------------------------------