File: cgimgscl.pro

package info (click to toggle)
coyote 2019.01.29-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster
  • size: 6,316 kB
  • sloc: python: 184; makefile: 14; sh: 13
file content (419 lines) | stat: -rw-r--r-- 20,371 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
; docformat = 'rst'
;
; NAME:
;   cgImgScl
;
; PURPOSE:
;   This function scales an image using the same keywords and scaling available in 
;   cgImage and cgStretch.
;
;******************************************************************************************;
;                                                                                          ;
;  Copyright (c) 2012, 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.                            ;
;******************************************************************************************;
;+
; This function scales an image using the same keywords and scaling available in 
; cgImage and cgStretch. Set the `Stretch` keyword for the types of image scaling
; or stretching available.
; 
; :Categories:
;    Graphics, Utilities
;    
; :Returns:
;     Returns a scaled image.
; 
; :Params:
;    image: in, required
;       The input image that is to be scaled. Only 2D images can be scaled, although
;       true-color images can be resized.
;    xsize: in, optional
;       The output X size of the image.
;    ysize: in, optional
;       The output Y size of the image.
;   
; :Keywords:
;    bottom: in, optional, type=integer, default=0
;         If the `SCALE` keyword is set, the image is scaled before display so that all 
;         displayed pixels have values greater than or equal to `BOTTOM` and less than 
;         or equal to `TOP`.
;    beta: in, optional, type=float, default=3.0
;         The beta factor in a Hyperpolic Sine stretch.
;    clip: in, optional, type=float, default=2
;         A number between 0 and 50 that indicates the percentage of pixels to clip
;         off either end of the image histogram before performing a linear stretch.
;    constant: in, optional, type=float, default=1.0
;         A constant value applied in a logarithmic stretch.
;    exclude: in, optional, type=numeric
;         The value to exclude in a standard deviation stretch.
;    exponent: in, optional, type=float, default=4.0
;         The logarithm exponent in a compression stretch.
;    gamma: in, optional, type=float, default=1.5
;         The gamma factor in a gamma stretch.
;    interpolate: in, optional, type=boolean, default=0
;         Set this keyword to interpolate with bilinear interpolation the display image as it 
;         is sized to its final position in the display window. Interpolation will potentially 
;         create image values that do not exist in the original image. The default is to do no
;         interpolation, so that image values to not change upon resizing. Interpolation can
;         result in smoother looking final images.
;    maxvalue: in, optional, type=varies
;         If this value is defined, the data is linearly scaled between `MINVALUE`
;         and `MAXVALUE`. `MAXVALUE` is set to `MAX`(image) by default. Setting this 
;         keyword to a value automatically sets `SCALE` to 1. If the maximum value of the 
;         image is greater than 255, this keyword is defined and SCALE=1.
;    mean: in, optional, type=float, default=0.5
;         The mean factor in a compression stretch.
;    minus_one: in, optional, type=boolean, default=0
;         The value of this keyword is passed along to the cgResizeImage
;         command. It prevents cgResizeImage from adding an extra row and
;         column to the resulting array, which can be a problem with
;         small image arrays. 
;    minvalue: in, optional, type=varies
;         If this value is defined, the data is linearly scaled between MINVALUE
;         and `MAXVALUE`. `MINVALUE` is set to `MIN`(image) by default. Setting this 
;         keyword to a value automatically sets SCALE=1. If the minimum value of the 
;         image is less than 0, this keyword is defined and SCALE=1.
;    missing_index: in, optional, type=integer, default=255
;         The index of the missing color in the final byte scaled image.
;    missing_value: in, optional, type=integer
;         The number that represents the missing value in the image.
;    multiplier: in, optional, type=float
;         The multiplication factor in a standard deviation stretch. The standard deviation
;         is multiplied by this factor to produce the thresholds for a linear stretch.
;    ncolors: in, optional, type=integer, default=256
;         If this keyword is supplied, the `TOP` keyword is ignored and the TOP keyword 
;         is set equal to  NCOLORS-1. This keyword is provided to make cgImgScl easier 
;         to use with the color-loading programs such as cgLOADCT::
;
;              cgLoadCT, 5, NColors=100, Bottom=100
;              scaled = cgImgScl(image, NColors=100, Bottom=100)
;                  
;         Setting this keyword to a value automatically sets SCALE=1 and STRETCH='LINEAR', if not
;         defined otherwise. Available only with 2D images.
;    negative: in, optional, type=boolean, default=0
;         Set this keyword if you want to display the image with a negative or reverse stretch.
;    scale: in, optional, type=boolean, default=0
;         Set this keyword to byte scale the image before display. If this keyword is not set, 
;         the image is not scaled before display. This keyword will be set automatically by using
;         any of the keywords normally associated with byte scaling an image.
;    stretch: in, optional, type=integer/string, default=0
;         The type of scaling performed prior to display. May be specified as a number 
;         or as a string (e.g, 3 or "Log"). Available only with 2D images. If  Min(image)
;         is less than zero or Max(image) is greater than 255, then the default value for
;         stretch is 1.
;
;         Number   Type of Stretch::
;             0         None           No scaling whatsoever is done.
;             1         Linear         scaled = BytScl(image, MIN=minValue, MAX=maxValue)
;             2         Linear 2%      A histogram stretch, with a percentage of pixels clipped at both the top and bottom
;             3         Gamma          scaled = cgGmaScl(image, MIN=minValue, MAX=maxValue, Gamma=gamma)
;             4         Log            scaled = cgLogScl(image, MIN=minValue, MAX=maxValue, Mean=mean, Exponent=exponent)
;             5         Asinh          scaled = cgAsinhScl(image, MIN=minValue, MAX=maxValue, Beta=beta)
;             6         SquareRoot     A linear stretch of the square root histogram of the image values.
;             7         Equalization   A linear stretch of the histogram equalized image histogram.
;             8         Gaussian       A Gaussian normal function is applied to the image histogram.
;             9         MODIS          Scaling done in the differential manner of the MODIS Rapid Response Team
;                                      and implemented in the Coyote Library routine ScaleModis.
;             10        StdDev         Standard deviation stretch. scaled = cgSDevScl(image, MULTIPLIER=2).
;             11        Compression    Compress mid-tones in image with cgCompressScl.
;             
;    sigma: in, optional, type=float, default=1.0
;         The sigma scale factor in a Gaussian stretch.
;    top: in, optional, type=integer, default=255
;         If the `SCALE` keyword is set, the image is scaled before display so that all 
;         displayed pixels have values greater than or equal to `BOTTOM` and less than 
;         or equal to `TOP`.
;         
; :Examples:
;    Used to for image display::
;       IDL> scaledImage = cgImgScl(image, Stretch=4, Exponent=2)
;       IDL> cgImage, scaledImage[0:100, 200:400], /Keep_Aspect
;     
; :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 by David W. Fanning, 21 September 2012. 
;       Only define MISSING_INDEX value if needed. Change to support TRANSPARENT keyword
;          in cgImage. 18 October 2012. DWF.
;       Only 2D images can be scaled. 18 October 2012. DWF.
;       Made LOG stretch a real log stretch and add a compression stretch. 27 March 2015. DWF.
;
; :Copyright:
;     Copyright (c) 2012-2015, Fanning Software Consulting, Inc.

;-
FUNCTION cgImgScl, image, xsize, ysize, $
   BOTTOM=bottom, $
   BETA=beta, $
   CLIP=clip, $
   CONSTANT=contant, $
   EXCLUDE=exclude, $
   EXPONENT=exponent, $
   GAMMA=gamma, $
   INTERPOLATE=interpolate, $
   MAXVALUE=maxvalue, $
   MEAN=mean, $
   MINUS_ONE=minus_one, $
   MINVALUE=minvalue, $
   MISSING_INDEX=missing_index, $
   MISSING_VALUE=missing_value, $
   MULTIPLIER=multiplier, $
   NCOLORS=ncolors, $
   NEGATIVE=negative, $
   SCALE=scale, $
   STRETCH=stretch, $
   SIGMA=sigma, $
   TOP=top

   Compile_Opt idl2
   
    ; Error handling.
    Catch, theError
    IF theError NE 0 THEN BEGIN
       Catch, /Cancel
       ok = cgErrorMsg()
       RETURN, image
    ENDIF
    
    ; Did the user want to scale the image?
    ; If either MIN or MAX are set, this implies SCALE=1.
    ; If min LT 0 or max GT 255, this implies SCALE=1.
    ; If NCOLORS is used, this implies SCALE=1 and STRETCH='linear', if STRETCH is undefined.
    IF N_Elements(min) EQ 0 THEN min = Min(image, /NAN) ELSE scale = 1
    IF N_Elements(max) EQ 0 THEN max = Max(image, /NAN) ELSE scale = 1
    IF (min LT 0) OR (max GT 255) THEN scale = 1
    IF N_Elements(top) EQ 0 THEN top = (N_Elements(missing_value) NE 0) ? !D.TABLE_SIZE - 2 : !D.TABLE_SIZE - 1
    IF N_Elements(bottom) EQ 0 THEN bottom = 0B
    IF N_Elements(ncolors) NE 0 THEN BEGIN
        top = (N_Elements(missing_value) NE 0) ? (ncolors - 2) < 255 : (ncolors - 1)
        scale = 1
     ENDIF
    
    ncolors = top-bottom+1
    negative = Keyword_Set(negative)
    scale = Keyword_Set(scale)
    IF scale THEN BEGIN
       IF N_Elements(stretch) EQ 0 THEN stretch = 1
    ENDIF 
    SetDefaultValue, beta, 3.0
    SetDefaultValue, clip, 2
    SetDefaultValue, exponent, 4.0
    SetDefaultValue, gamma, 1.5 
    SetDefaultValue, mean, 1.0
    SetDefaultValue, negative, 0
    SetDefaultValue, sigma, 1.0
    SetDefaultValue, stretch, 0
    
    ; Missing index only defined if needed. Change to support transparent images in cgImage.
    IF N_Elements(missing_value) NE 0 THEN IF N_Elements(missing_index) EQ 0 THEN missing_index = 255
    
    ; Make sure you can specify the type of stretch with a string name.
    IF Size(stretch, /TNAME) EQ 'STRING' THEN BEGIN
        stretches = ['None', 'Linear', 'Clip', 'Gamma', 'Log', 'ASinh', $
              'SquareRoot', 'Equalization', 'Gaussian', 'MODIS', 'StdDev']
       index = Where(StrUpCase(stretch) EQ StrUpCase(stretches), count)
       IF count GT 0 THEN stretch=index ELSE Message, 'Cannot find stretch: ' + StrUpCase(stretch)
    ENDIF
    IF stretch NE 0 THEN scale = 1
    
    ; Can't stretch true-color images.
    IF Size(image, /N_DIMENSIONS) NE 2 THEN scale = 0
    
   ; I would like to avoid making a copy of the image, if possible.
   ; If nothing needs to be done, just return the image. Only 2D images
   ; can proceed.
   IF (N_Elements(xsize) EQ 0) && $
      (N_Elements(missing_value) EQ 0) && $
      ~Keyword_Set(scale) THEN RETURN, image
      
   ; Is there a missing value to worry about? We can only worry
   ; about missing values with 2D image arrays.
   ndims = Size(image, /N_DIMENSIONS)
   IF (N_Elements(missing_value) NE 0) && (ndims EQ 2) THEN BEGIN
   
       ; Get the image type.
       imageType = Size(image, /TNAME)
       
       ; Create a temporary image variable. If you will be scaling the data,
       ; make the image a float if it is not float or double already.
       CASE imageType OF
          'FLOAT': tempImage = image
          'DOUBLE': tempImage = image
          ELSE: tempImage = Float(image) 
       ENDCASE
       
       ; The missing value may be the symbol for NAN.
       IF Finite(missing_value) THEN BEGIN
           missingIndices = Where(tempImage EQ missing_value, missingCnt)
       ENDIF ELSE BEGIN
           missingIndices = Where(Finite(tempImage) EQ 0, missingCnt)
       ENDELSE
       
       ; Set the missing indices to the correct NAN value.
       IF imageType EQ 'DOUBLE' THEN BEGIN
           IF missingCnt GT 0 THEN tempImage[missingIndices] = !Values.D_NAN
       ENDIF ELSE BEGIN
           IF missingCnt GT 0 THEN tempImage[missingIndices] = !Values.F_NAN
       ENDELSE
   
   ENDIF
   
   ; Do you need scaling?
   IF Keyword_Set(scale) || (stretch NE 0) THEN BEGIN
   
      ; Create a temporary image, if you don't already have one.
      IF N_Elements(tempImage) EQ 0 THEN BEGIN
          imageType = Size(image, /TNAME)
          CASE imageType OF
              'FLOAT': tempimage = image
              'DOUBLE': tempimage = image
              ELSE: tempImage = Float(image) 
          ENDCASE
       ENDIF
      
      ; Select the particular kind of stretch you want to do. Unfortunately, we
      ; can still cause underflow error messages when doing stretch, despite best
      ; attempts to prevent this. Turn these messages off here.
      curExcept = !Except
      !Except = 0      
       CASE stretch OF
       
;             0         None           No scaling whatsoever is done.
;             1         Linear         scaled = BytScl(image, MIN=minValue, MAX=maxValue)
;             2         Clip           A histogram stretch, with a percentage of pixels clipped at both the top and bottom
;             3         Gamma          scaled = cgGmaScl(image, MIN=minValue, MAX=maxValue, Gamma=gamma)
;             4         Log            scaled =  cgLogScl(image, MIN=minValue, MAX=maxValue, CONSTANT=constant)
;             5         Asinh          scaled = cgAsinhScl(image, MIN=minValue, MAX=maxValue, Beta=beta)
;             6         SquareRoot     A linear stretch of the square root histogram of the image values.
;             7         Equalization   A linear stretch of the histogram equalized image histogram.
;             8         Gaussian       A Gaussian normal function is applied to the image histogram.
;             9         MODIS          Scaling done in the differential manner of the MODIS Rapid Response Team
;             10        StdDev         A standard deviation stretch.
;             11        Compression    Compress mid-tones in image with cgCompressScl.

          0: ; No stretch at all. 
       
          1: BEGIN ; Linear stretch.
             tempImage = BytScl(tempImage, Max=maxvalue, Min=minvalue, /NAN, TOP=top) + bottom
             IF negative THEN tempImage = Byte(top) - tempImage
             END
    
          2: BEGIN ; Histogram clip stretch.
             tempImage = cgClipScl(tempImage, clip, OMIN=bottom, OMAX=top, NEGATIVE=negative)
             END

          3: BEGIN ; Gamma log scale stretch.
             tempImage = cgGmaScl(tempImage, Max=maxvalue, Min=minvalue, $
                       Gamma=gamma, Negative=negative, OMAX=top, OMIN=bottom)
             END
    
          4: BEGIN ; Log scale stretch.
             tempImage =  cgLogScl(tempImage, Max=maxvalue, Min=minvalue, $
                       Mean=mean, Exponent=exponent, Negative=negative, $
                       OMIN=bottom, OMAX=top)
             END
    
          5: BEGIN ; Hyperpolic sine stretch.
             tempImage = cgASinhScl(tempImage, Max=maxvalue, Min=minvalue, $
                      BETA=beta, Negative=negative, OMAX=top, OMIN=bottom)
             END
               
    
          6: BEGIN ; Square Root stretch.
             tempImage = BytScl(SQRT(tempImage), Max=maxvalue, Min=minvalue, /NAN, TOP=top) + bottom
             IF negative THEN tempImage = Byte(top) - tempImage
             END
    
          7: BEGIN ; Histogram equalization stretch.
             IF (top EQ 255) && (bottom EQ 0) THEN BEGIN
                 tempImage = Hist_Equal(tempImage, MaxV=maxvalue, MinV=minvalue)
             ENDIF ELSE BEGIN
                 tempImage = Bytscl(Float(Hist_Equal(tempImage, MaxV=maxvalue, MinV=minvalue)), /NAN, TOP=top) + bottom
             ENDELSE
             IF negative THEN tempImage = Byte(top) - tempImage
             END
    
          8: BEGIN ; Gaussian stretch.
             tempImage = cgGaussScl(tempImage, Max=maxvalue, Min=minvalue, $
                       Sigma=sigma, Negative=negative, OMIN=bottom, OMAX=top)
             END
         
          9: BEGIN ; MODIS image stretch.
             tempImage = ScaleModis(tempImage)
             END
             
          10: BEGIN ; Standard deviation stretch.
              tempImage = cgSDevScl(tempImage, MULTIPLIER=multiplier, EXCLUDE=exclude, $
                   Negative=negative, OMAX=top, OMIN=bottom)
              END
               
          11: BEGIN ; Compression stretch.
                  tempImage = cgCompressScl(tempImage, Max=maxvalue, Min=minvalue, $
                       Mean=mean, Exponent=exponent, Negative=negative, $
                       OMIN=bottom, OMAX=top)
              END
            ELSE: Message, 'Unknown scaling index.'
            
       ENDCASE
       
       ; Clear the math error register and turn normal error checking on.
       void = Check_Math()
       !Except = curExcept
       
   ENDIF
   
   ; After scaling, you may need to replace missing values with the
   ; missing index.
   IF N_Elements(missingCnt) NE 0 THEN BEGIN
      IF missingCnt GT 0 THEN tempImage[missingIndices] = missing_index
   ENDIF
   
   ; If you created a temporary image, then return that.
   ; Otherwise you can return the original image, modified
   ; to the appropriate size.
   IF N_Elements(tempImage) EQ 0 THEN BEGIN
       IF (N_Elements(xsize) EQ 0) THEN BEGIN
           RETURN, image
       ENDIF ELSE BEGIN
           RETURN, cgResizeImage(image, xsize, ysize, $
                    INTERP=interpolate, MINUS_ONE=minus_one)
       ENDELSE
   ENDIF ELSE BEGIN
       IF (N_Elements(xsize) EQ 0) THEN BEGIN
           RETURN, tempImage
       ENDIF ELSE BEGIN
           RETURN, cgResizeImage(tempImage, xsize, ysize, $
                    INTERP=interpolate, MINUS_ONE=minus_one)
       ENDELSE
   ENDELSE
END