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Use const struct quirc parameter in otsu() function and fix tabs

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This commit is contained in:
Claudio Felber 2019-04-30 18:44:59 +02:00
parent 96a5a380fb
commit 766f79ce7c
1 changed files with 54 additions and 54 deletions
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108
lib/identify.c
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@ -174,55 +174,55 @@ static void flood_fill_seed(struct quirc *q, int x, int y, int from, int to,
* Adaptive thresholding * Adaptive thresholding
*/ */
uint8_t otsu(struct quirc *q) uint8_t otsu(const struct quirc *q)
{ {
int numPixels = q->w * q->h; int numPixels = q->w * q->h;
// Calculate histogram // Calculate histogram
const int HISTOGRAM_SIZE = 256; const int HISTOGRAM_SIZE = 256;
unsigned int histogram[HISTOGRAM_SIZE]; unsigned int histogram[HISTOGRAM_SIZE];
memset(histogram, 0, (HISTOGRAM_SIZE) * sizeof(unsigned int)); memset(histogram, 0, (HISTOGRAM_SIZE) * sizeof(unsigned int));
uint8_t* ptr = q->image; uint8_t* ptr = q->image;
int length = numPixels; int length = numPixels;
while (length--) { while (length--) {
uint8_t value = *ptr++; uint8_t value = *ptr++;
histogram[value]++; histogram[value]++;
} }
// Calculate weighted sum of histogram values // Calculate weighted sum of histogram values
int sum = 0; int sum = 0;
for (int i = 0; i < HISTOGRAM_SIZE; ++i) { for (int i = 0; i < HISTOGRAM_SIZE; ++i) {
sum += i * histogram[i]; sum += i * histogram[i];
} }
// Compute threshold // Compute threshold
int sumB = 0; int sumB = 0;
int q1 = 0; int q1 = 0;
double max = 0; double max = 0;
uint8_t threshold = 0; uint8_t threshold = 0;
for (int i = 0; i < HISTOGRAM_SIZE; ++i) { for (int i = 0; i < HISTOGRAM_SIZE; ++i) {
// Weighted background // Weighted background
q1 += histogram[i]; q1 += histogram[i];
if (q1 == 0) if (q1 == 0)
continue; continue;
// Weighted foreground // Weighted foreground
const int q2 = numPixels - q1; const int q2 = numPixels - q1;
if (q2 == 0) if (q2 == 0)
break; break;
sumB += i * histogram[i]; sumB += i * histogram[i];
const double m1 = (double)sumB / q1; const double m1 = (double)sumB / q1;
const double m2 = ((double)sum - sumB) / q2; const double m2 = ((double)sum - sumB) / q2;
const double m1m2 = m1 - m2; const double m1m2 = m1 - m2;
const double variance = m1m2 * m1m2 * q1 * q2; const double variance = m1m2 * m1m2 * q1 * q2;
if (variance > max) { if (variance > max) {
threshold = i; threshold = i;
max = variance; max = variance;
} }
} }
return threshold; return threshold;
} }
static void area_count(void *user_data, int y, int left, int right) static void area_count(void *user_data, int y, int left, int right)
@ -1071,17 +1071,17 @@ static void test_grouping(struct quirc *q, int i)
static void pixels_setup(struct quirc *q, uint8_t threshold) static void pixels_setup(struct quirc *q, uint8_t threshold)
{ {
if (sizeof(*q->image) == sizeof(*q->pixels)) { if (sizeof(*q->image) == sizeof(*q->pixels)) {
q->pixels = (quirc_pixel_t *)q->image; q->pixels = (quirc_pixel_t *)q->image;
} }
uint8_t* source = q->image; uint8_t* source = q->image;
quirc_pixel_t* dest = q->pixels; quirc_pixel_t* dest = q->pixels;
int length = q->w * q->h; int length = q->w * q->h;
while (length--) { while (length--) {
uint8_t value = *source++; uint8_t value = *source++;
*dest++ = (value < threshold) ? QUIRC_PIXEL_BLACK : QUIRC_PIXEL_WHITE; *dest++ = (value < threshold) ? QUIRC_PIXEL_BLACK : QUIRC_PIXEL_WHITE;
} }
} }
uint8_t *quirc_begin(struct quirc *q, int *w, int *h) uint8_t *quirc_begin(struct quirc *q, int *w, int *h)
@ -1102,8 +1102,8 @@ void quirc_end(struct quirc *q)
{ {
int i; int i;
uint8_t threshold = otsu(q); uint8_t threshold = otsu(q);
pixels_setup(q, threshold); pixels_setup(q, threshold);
for (i = 0; i < q->h; i++) for (i = 0; i < q->h; i++)
finder_scan(q, i); finder_scan(q, i);