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1 /* | |
2 * Copyright 2013 Google Inc. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license that can be | |
5 * found in the LICENSE file. | |
6 */ | |
7 #include <cmath> | |
8 #include <math.h> | |
9 | |
10 #include "SkBitmap.h" | |
11 #include "skpdiff_util.h" | |
12 #include "SkPMetric.h" | |
13 #include "SkPMetricUtil_generated.h" | |
14 | |
15 struct RGB { | |
16 float r, g, b; | |
17 }; | |
18 | |
19 struct LAB { | |
20 float l, a, b; | |
21 }; | |
22 | |
23 template<class T> | |
24 struct Image2D { | |
25 int width; | |
26 int height; | |
27 T* image; | |
28 | |
29 Image2D(int w, int h) | |
30 : width(w), | |
31 height(h) { | |
32 SkASSERT(w > 0); | |
33 SkASSERT(h > 0); | |
34 image = new T[w * h]; | |
35 } | |
36 | |
37 ~Image2D() { delete[] image; } | |
38 | |
39 void readPixel(int x, int y, T* pixel) const { | |
40 SkASSERT(x >= 0); | |
41 SkASSERT(y >= 0); | |
42 SkASSERT(x < width); | |
43 SkASSERT(y < height); | |
44 *pixel = image[y * width + x]; | |
45 } | |
46 | |
47 T* getRow(int y) const { | |
48 return &image[y * width]; | |
49 } | |
50 | |
51 void writePixel(int x, int y, const T& pixel) { | |
52 SkASSERT(x >= 0); | |
53 SkASSERT(y >= 0); | |
54 SkASSERT(x < width); | |
55 SkASSERT(y < height); | |
56 image[y * width + x] = pixel; | |
57 } | |
58 }; | |
59 | |
60 typedef Image2D<float> ImageL; | |
61 typedef Image2D<RGB> ImageRGB; | |
62 typedef Image2D<LAB> ImageLAB; | |
63 | |
64 template<class T> | |
65 struct ImageArray | |
66 { | |
67 int slices; | |
68 Image2D<T>** image; | |
69 | |
70 ImageArray(int w, int h, int s) | |
71 : slices(s) { | |
72 SkASSERT(s > 0); | |
73 image = new Image2D<T>* [s]; | |
74 for (int sliceIndex = 0; sliceIndex < slices; sliceIndex++) { | |
75 image[sliceIndex] = new Image2D<T>(w, h); | |
76 } | |
77 } | |
78 | |
79 ~ImageArray() { | |
80 for (int sliceIndex = 0; sliceIndex < slices; sliceIndex++) { | |
81 delete image[sliceIndex]; | |
82 } | |
83 delete[] image; | |
84 } | |
85 | |
86 Image2D<T>* getLayer(int z) const { | |
87 SkASSERT(z >= 0); | |
88 SkASSERT(z < slices); | |
89 return image[z]; | |
90 } | |
91 }; | |
92 | |
93 typedef ImageArray<float> ImageL3D; | |
94 | |
95 | |
96 #define MAT_ROW_MULT(rc,gc,bc) r*rc + g*gc + b*bc | |
97 | |
98 static void adobergb_to_cielab(float r, float g, float b, LAB* lab) { | |
99 // Conversion of Adobe RGB to XYZ taken from from "Adobe RGB (1998) ColorIma
ge Encoding" | |
100 // URL:http://www.adobe.com/digitalimag/pdfs/AdobeRGB1998.pdf | |
101 // Section: 4.3.5.3 | |
102 // See Also: http://en.wikipedia.org/wiki/Adobe_rgb | |
103 float x = MAT_ROW_MULT(0.57667f, 0.18556f, 0.18823f); | |
104 float y = MAT_ROW_MULT(0.29734f, 0.62736f, 0.07529f); | |
105 float z = MAT_ROW_MULT(0.02703f, 0.07069f, 0.99134f); | |
106 | |
107 // The following is the white point in XYZ, so it's simply the row wise addi
tion of the above | |
108 // matrix. | |
109 const float xw = 0.5767f + 0.185556f + 0.188212f; | |
110 const float yw = 0.297361f + 0.627355f + 0.0752847f; | |
111 const float zw = 0.0270328f + 0.0706879f + 0.991248f; | |
112 | |
113 // This is the XYZ color point relative to the white point | |
114 float f[3] = { x / xw, y / yw, z / zw }; | |
115 | |
116 // Conversion from XYZ to LAB taken from | |
117 // http://en.wikipedia.org/wiki/CIELAB#Forward_transformation | |
118 for (int i = 0; i < 3; i++) { | |
119 if (f[i] >= 0.008856f) { | |
120 f[i] = SkPMetricUtil::get_cube_root(f[i]); | |
121 } else { | |
122 f[i] = 7.787f * f[i] + 4.0f / 29.0f; | |
123 } | |
124 } | |
125 lab->l = 116.0f * f[1] - 16.0f; | |
126 lab->a = 500.0f * (f[0] - f[1]); | |
127 lab->b = 200.0f * (f[1] - f[2]); | |
128 } | |
129 | |
130 /// Converts a 8888 bitmap to LAB color space and puts it into the output | |
131 static bool bitmap_to_cielab(const SkBitmap* bitmap, ImageLAB* outImageLAB) { | |
132 SkBitmap bm8888; | |
133 if (bitmap->colorType() != kN32_SkColorType) { | |
134 if (!bitmap->copyTo(&bm8888, kN32_SkColorType)) { | |
135 return false; | |
136 } | |
137 bitmap = &bm8888; | |
138 } | |
139 | |
140 int width = bitmap->width(); | |
141 int height = bitmap->height(); | |
142 SkASSERT(outImageLAB->width == width); | |
143 SkASSERT(outImageLAB->height == height); | |
144 | |
145 bitmap->lockPixels(); | |
146 RGB rgb; | |
147 LAB lab; | |
148 for (int y = 0; y < height; y++) { | |
149 unsigned char* row = (unsigned char*)bitmap->getAddr(0, y); | |
150 for (int x = 0; x < width; x++) { | |
151 // Perform gamma correction which is assumed to be 2.2 | |
152 rgb.r = SkPMetricUtil::get_gamma(row[x * 4 + 2]); | |
153 rgb.g = SkPMetricUtil::get_gamma(row[x * 4 + 1]); | |
154 rgb.b = SkPMetricUtil::get_gamma(row[x * 4 + 0]); | |
155 adobergb_to_cielab(rgb.r, rgb.g, rgb.b, &lab); | |
156 outImageLAB->writePixel(x, y, lab); | |
157 } | |
158 } | |
159 bitmap->unlockPixels(); | |
160 return true; | |
161 } | |
162 | |
163 // From Barten SPIE 1989 | |
164 static float contrast_sensitivity(float cyclesPerDegree, float luminance) { | |
165 float a = 440.0f * powf(1.0f + 0.7f / luminance, -0.2f); | |
166 float b = 0.3f * powf(1.0f + 100.0f / luminance, 0.15f); | |
167 float exp = expf(-b * cyclesPerDegree); | |
168 float root = sqrtf(1.0f + 0.06f * expf(b * cyclesPerDegree)); | |
169 if (!SkScalarIsFinite(exp) || !SkScalarIsFinite(root)) { | |
170 return 0; | |
171 } | |
172 return a * cyclesPerDegree * exp * root; | |
173 } | |
174 | |
175 #if 0 | |
176 // We're keeping these around for reference and in case the lookup tables are no
longer desired. | |
177 // They are no longer called by any code in this file. | |
178 | |
179 // From Daly 1993 | |
180 static float visual_mask(float contrast) { | |
181 float x = powf(392.498f * contrast, 0.7f); | |
182 x = powf(0.0153f * x, 4.0f); | |
183 return powf(1.0f + x, 0.25f); | |
184 } | |
185 | |
186 // From Ward Larson Siggraph 1997 | |
187 static float threshold_vs_intensity(float adaptationLuminance) { | |
188 float logLum = log10f(adaptationLuminance); | |
189 float x; | |
190 if (logLum < -3.94f) { | |
191 x = -2.86f; | |
192 } else if (logLum < -1.44f) { | |
193 x = powf(0.405f * logLum + 1.6f, 2.18) - 2.86f; | |
194 } else if (logLum < -0.0184f) { | |
195 x = logLum - 0.395f; | |
196 } else if (logLum < 1.9f) { | |
197 x = powf(0.249f * logLum + 0.65f, 2.7f) - 0.72f; | |
198 } else { | |
199 x = logLum - 1.255f; | |
200 } | |
201 return powf(10.0f, x); | |
202 } | |
203 | |
204 #endif | |
205 | |
206 /// Simply takes the L channel from the input and puts it into the output | |
207 static void lab_to_l(const ImageLAB* imageLAB, ImageL* outImageL) { | |
208 for (int y = 0; y < imageLAB->height; y++) { | |
209 for (int x = 0; x < imageLAB->width; x++) { | |
210 LAB lab; | |
211 imageLAB->readPixel(x, y, &lab); | |
212 outImageL->writePixel(x, y, lab.l); | |
213 } | |
214 } | |
215 } | |
216 | |
217 /// Convolves an image with the given filter in one direction and saves it to th
e output image | |
218 static void convolve(const ImageL* imageL, bool vertical, ImageL* outImageL) { | |
219 SkASSERT(imageL->width == outImageL->width); | |
220 SkASSERT(imageL->height == outImageL->height); | |
221 | |
222 const float matrix[] = { 0.05f, 0.25f, 0.4f, 0.25f, 0.05f }; | |
223 const int matrixCount = sizeof(matrix) / sizeof(float); | |
224 const int radius = matrixCount / 2; | |
225 | |
226 // Keep track of what rows are being operated on for quick access. | |
227 float* rowPtrs[matrixCount]; // Because matrixCount is constant, this won't
create a VLA | |
228 for (int y = radius; y < matrixCount; y++) { | |
229 rowPtrs[y] = imageL->getRow(y - radius); | |
230 } | |
231 float* writeRow = outImageL->getRow(0); | |
232 | |
233 for (int y = 0; y < imageL->height; y++) { | |
234 for (int x = 0; x < imageL->width; x++) { | |
235 float lSum = 0.0f; | |
236 for (int xx = -radius; xx <= radius; xx++) { | |
237 int nx = x; | |
238 int ny = y; | |
239 | |
240 // We mirror at edges so that edge pixels that the filter weight
ing still makes | |
241 // sense. | |
242 if (vertical) { | |
243 ny += xx; | |
244 if (ny < 0) { | |
245 ny = -ny; | |
246 } | |
247 if (ny >= imageL->height) { | |
248 ny = imageL->height + (imageL->height - ny - 1); | |
249 } | |
250 } else { | |
251 nx += xx; | |
252 if (nx < 0) { | |
253 nx = -nx; | |
254 } | |
255 if (nx >= imageL->width) { | |
256 nx = imageL->width + (imageL->width - nx - 1); | |
257 } | |
258 } | |
259 | |
260 float weight = matrix[xx + radius]; | |
261 lSum += rowPtrs[ny - y + radius][nx] * weight; | |
262 } | |
263 writeRow[x] = lSum; | |
264 } | |
265 // As we move down, scroll the row pointers down with us | |
266 for (int y = 0; y < matrixCount - 1; y++) | |
267 { | |
268 rowPtrs[y] = rowPtrs[y + 1]; | |
269 } | |
270 rowPtrs[matrixCount - 1] += imageL->width; | |
271 writeRow += imageL->width; | |
272 } | |
273 } | |
274 | |
275 static double pmetric(const ImageLAB* baselineLAB, const ImageLAB* testLAB, int*
poiCount) { | |
276 SkASSERT(baselineLAB); | |
277 SkASSERT(testLAB); | |
278 SkASSERT(poiCount); | |
279 | |
280 int width = baselineLAB->width; | |
281 int height = baselineLAB->height; | |
282 int maxLevels = 0; | |
283 | |
284 // Calculates how many levels to make by how many times the image can be div
ided in two | |
285 int smallerDimension = width < height ? width : height; | |
286 for ( ; smallerDimension > 1; smallerDimension /= 2) { | |
287 maxLevels++; | |
288 } | |
289 | |
290 // We'll be creating new arrays with maxLevels - 2, and ImageL3D requires ma
xLevels > 0, | |
291 // so just return failure if we're less than 3. | |
292 if (maxLevels <= 2) { | |
293 return 0.0; | |
294 } | |
295 | |
296 const float fov = SK_ScalarPI / 180.0f * 45.0f; | |
297 float contrastSensitivityMax = contrast_sensitivity(3.248f, 100.0f); | |
298 float pixelsPerDegree = width / (2.0f * tanf(fov * 0.5f) * 180.0f / SK_Scala
rPI); | |
299 | |
300 ImageL3D baselineL(width, height, maxLevels); | |
301 ImageL3D testL(width, height, maxLevels); | |
302 ImageL scratchImageL(width, height); | |
303 float* cyclesPerDegree = new float[maxLevels]; | |
304 float* thresholdFactorFrequency = new float[maxLevels - 2]; | |
305 float* contrast = new float[maxLevels - 2]; | |
306 | |
307 lab_to_l(baselineLAB, baselineL.getLayer(0)); | |
308 lab_to_l(testLAB, testL.getLayer(0)); | |
309 | |
310 // Compute cpd - Cycles per degree on the pyramid | |
311 cyclesPerDegree[0] = 0.5f * pixelsPerDegree; | |
312 for (int levelIndex = 1; levelIndex < maxLevels; levelIndex++) { | |
313 cyclesPerDegree[levelIndex] = cyclesPerDegree[levelIndex - 1] * 0.5f; | |
314 } | |
315 | |
316 // Contrast sensitivity is based on image dimensions. Therefore it cannot be
statically | |
317 // generated. | |
318 float* contrastSensitivityTable = new float[maxLevels * 1000]; | |
319 for (int levelIndex = 0; levelIndex < maxLevels; levelIndex++) { | |
320 for (int csLum = 0; csLum < 1000; csLum++) { | |
321 contrastSensitivityTable[levelIndex * 1000 + csLum] = | |
322 contrast_sensitivity(cyclesPerDegree[levelIndex], (float)csLum / 10.0
f + 1e-5f); | |
323 } | |
324 } | |
325 | |
326 // Compute G - The convolved lum for the baseline | |
327 for (int levelIndex = 1; levelIndex < maxLevels; levelIndex++) { | |
328 convolve(baselineL.getLayer(levelIndex - 1), false, &scratchImageL); | |
329 convolve(&scratchImageL, true, baselineL.getLayer(levelIndex)); | |
330 } | |
331 for (int levelIndex = 1; levelIndex < maxLevels; levelIndex++) { | |
332 convolve(testL.getLayer(levelIndex - 1), false, &scratchImageL); | |
333 convolve(&scratchImageL, true, testL.getLayer(levelIndex)); | |
334 } | |
335 | |
336 // Compute F_freq - The elevation f | |
337 for (int levelIndex = 0; levelIndex < maxLevels - 2; levelIndex++) { | |
338 float cpd = cyclesPerDegree[levelIndex]; | |
339 thresholdFactorFrequency[levelIndex] = contrastSensitivityMax / | |
340 contrast_sensitivity(cpd, 100.0f)
; | |
341 } | |
342 | |
343 // Calculate F | |
344 for (int y = 0; y < height; y++) { | |
345 for (int x = 0; x < width; x++) { | |
346 float lBaseline; | |
347 float lTest; | |
348 baselineL.getLayer(0)->readPixel(x, y, &lBaseline); | |
349 testL.getLayer(0)->readPixel(x, y, &lTest); | |
350 | |
351 float avgLBaseline; | |
352 float avgLTest; | |
353 baselineL.getLayer(maxLevels - 1)->readPixel(x, y, &avgLBaseline); | |
354 testL.getLayer(maxLevels - 1)->readPixel(x, y, &avgLTest); | |
355 | |
356 float lAdapt = 0.5f * (avgLBaseline + avgLTest); | |
357 if (lAdapt < 1e-5f) { | |
358 lAdapt = 1e-5f; | |
359 } | |
360 | |
361 float contrastSum = 0.0f; | |
362 for (int levelIndex = 0; levelIndex < maxLevels - 2; levelIndex++) { | |
363 float baselineL0, baselineL1, baselineL2; | |
364 float testL0, testL1, testL2; | |
365 baselineL.getLayer(levelIndex + 0)->readPixel(x, y, &baselineL0)
; | |
366 testL. getLayer(levelIndex + 0)->readPixel(x, y, &testL0); | |
367 baselineL.getLayer(levelIndex + 1)->readPixel(x, y, &baselineL1)
; | |
368 testL. getLayer(levelIndex + 1)->readPixel(x, y, &testL1); | |
369 baselineL.getLayer(levelIndex + 2)->readPixel(x, y, &baselineL2)
; | |
370 testL. getLayer(levelIndex + 2)->readPixel(x, y, &testL2); | |
371 | |
372 float baselineContrast1 = fabsf(baselineL0 - baselineL1); | |
373 float testContrast1 = fabsf(testL0 - testL1); | |
374 float numerator = (baselineContrast1 > testContrast1) ? | |
375 baselineContrast1 : testContrast1; | |
376 | |
377 float baselineContrast2 = fabsf(baselineL2); | |
378 float testContrast2 = fabsf(testL2); | |
379 float denominator = (baselineContrast2 > testContrast2) ? | |
380 baselineContrast2 : testContrast2; | |
381 | |
382 // Avoid divides by close to zero | |
383 if (denominator < 1e-5f) { | |
384 denominator = 1e-5f; | |
385 } | |
386 contrast[levelIndex] = numerator / denominator; | |
387 contrastSum += contrast[levelIndex]; | |
388 } | |
389 | |
390 if (contrastSum < 1e-5f) { | |
391 contrastSum = 1e-5f; | |
392 } | |
393 | |
394 float F = 0.0f; | |
395 for (int levelIndex = 0; levelIndex < maxLevels - 2; levelIndex++) { | |
396 float contrastSensitivity = contrastSensitivityTable[levelIndex
* 1000 + | |
397 (int)(lAdap
t * 10.0)]; | |
398 float mask = SkPMetricUtil::get_visual_mask(contrast[levelIndex]
* | |
399 contrastSensitivity)
; | |
400 | |
401 F += contrast[levelIndex] + | |
402 thresholdFactorFrequency[levelIndex] * mask / contrastSum; | |
403 } | |
404 | |
405 if (F < 1.0f) { | |
406 F = 1.0f; | |
407 } | |
408 | |
409 if (F > 10.0f) { | |
410 F = 10.0f; | |
411 } | |
412 | |
413 | |
414 bool isFailure = false; | |
415 if (fabsf(lBaseline - lTest) > F * SkPMetricUtil::get_threshold_vs_i
ntensity(lAdapt)) { | |
416 isFailure = true; | |
417 } else { | |
418 LAB baselineColor; | |
419 LAB testColor; | |
420 baselineLAB->readPixel(x, y, &baselineColor); | |
421 testLAB->readPixel(x, y, &testColor); | |
422 float contrastA = baselineColor.a - testColor.a; | |
423 float contrastB = baselineColor.b - testColor.b; | |
424 float colorScale = 1.0f; | |
425 if (lAdapt < 10.0f) { | |
426 colorScale = lAdapt / 10.0f; | |
427 } | |
428 colorScale *= colorScale; | |
429 | |
430 if ((contrastA * contrastA + contrastB * contrastB) * colorScale
> F) | |
431 { | |
432 isFailure = true; | |
433 } | |
434 } | |
435 | |
436 if (isFailure) { | |
437 (*poiCount)++; | |
438 } | |
439 } | |
440 } | |
441 | |
442 delete[] cyclesPerDegree; | |
443 delete[] contrast; | |
444 delete[] thresholdFactorFrequency; | |
445 delete[] contrastSensitivityTable; | |
446 return 1.0 - (double)(*poiCount) / (width * height); | |
447 } | |
448 | |
449 bool SkPMetric::diff(SkBitmap* baseline, SkBitmap* test, const BitmapsToCreate&
bitmapsToCreate, | |
450 Result* result) const { | |
451 double startTime = get_seconds(); | |
452 | |
453 // Ensure the images are comparable | |
454 if (baseline->width() != test->width() || baseline->height() != test->height
() || | |
455 baseline->width() <= 0 || baseline->height() <= 0) { | |
456 return false; | |
457 } | |
458 | |
459 ImageLAB baselineLAB(baseline->width(), baseline->height()); | |
460 ImageLAB testLAB(baseline->width(), baseline->height()); | |
461 | |
462 if (!bitmap_to_cielab(baseline, &baselineLAB) || !bitmap_to_cielab(test, &te
stLAB)) { | |
463 return true; | |
464 } | |
465 | |
466 result->poiCount = 0; | |
467 result->result = pmetric(&baselineLAB, &testLAB, &result->poiCount); | |
468 result->timeElapsed = get_seconds() - startTime; | |
469 | |
470 return true; | |
471 } | |
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