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Updates to skin detection

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-Use 8x8 or 16x16 blocks.
-Option to use average of center pixel(s).

Change-Id: I7d962da30039d41385843e11606bc6482c7906f9
This commit is contained in:
Marco 2015-08-18 10:55:33 -07:00
parent 2fdb63fd72
commit 0092960d27
1 changed files with 44 additions and 19 deletions
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63
vp9/encoder/vp9_skin_detection.c
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@ -51,7 +51,7 @@ int vp9_skin_pixel(const uint8_t y, const uint8_t cb, const uint8_t cr) {
#ifdef OUTPUT_YUV_SKINMAP
// For viewing skin map on input source.
void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
int i, j, mi_row, mi_col;
int i, j, mi_row, mi_col, num_bl;
VP9_COMMON *const cm = &cpi->common;
uint8_t *y;
const uint8_t *src_y = cpi->Source->y_buffer;
@ -59,6 +59,15 @@ void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
const uint8_t *src_v = cpi->Source->v_buffer;
const int src_ystride = cpi->Source->y_stride;
const int src_uvstride = cpi->Source->uv_stride;
int y_bsize = 16; // Use 8x8 or 16x16.
int uv_bsize = y_bsize >> 1;
int ypos = y_bsize >> 1;
int uvpos = uv_bsize >> 1;
int shy = (y_bsize == 8) ? 3 : 4;
int shuv = shy - 1;
int fac = y_bsize / 8;
// Use center pixel or average of center 2x2 pixels.
int mode_filter = 1;
YV12_BUFFER_CONFIG skinmap;
memset(&skinmap, 0, sizeof(YV12_BUFFER_CONFIG));
if (vpx_alloc_frame_buffer(&skinmap, cm->width, cm->height,
@ -69,34 +78,50 @@ void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
}
memset(skinmap.buffer_alloc, 128, skinmap.frame_size);
y = skinmap.y_buffer;
// Loop through 8x8 blocks and set skin map based on center pixel of block.
// Loop through blocks and set skin map based on center pixel of block.
// Set y to white for skin block, otherwise set to source with gray scale.
// Ignore rightmost/bottom boundary blocks.
for (mi_row = 0; mi_row < cm->mi_rows - 1; ++mi_row) {
for (mi_col = 0; mi_col < cm->mi_cols - 1; ++mi_col) {
// Use middle pixel for each 8x8 block for skin detection.
// If middle pixel is skin, assign whole 8x8 block to skin.
const uint8_t ysource = src_y[4 * src_ystride + 4];
const uint8_t usource = src_u[2 * src_uvstride + 2];
const uint8_t vsource = src_v[2 * src_uvstride + 2];
for (mi_row = 0; mi_row < cm->mi_rows - 1; mi_row += fac) {
num_bl = 0;
for (mi_col = 0; mi_col < cm->mi_cols - 1; mi_col += fac) {
// Select pixel for each block for skin detection.
// Use center pixel, or 2x2 average at center.
uint8_t ysource = src_y[ypos * src_ystride + ypos];
uint8_t usource = src_u[uvpos * src_uvstride + uvpos];
uint8_t vsource = src_v[uvpos * src_uvstride + uvpos];
uint8_t ysource2 = src_y[(ypos + 1) * src_ystride + ypos];
uint8_t usource2 = src_u[(uvpos + 1) * src_uvstride + uvpos];
uint8_t vsource2 = src_v[(uvpos + 1) * src_uvstride + uvpos];
uint8_t ysource3 = src_y[ypos * src_ystride + (ypos + 1)];
uint8_t usource3 = src_u[uvpos * src_uvstride + (uvpos + 1)];
uint8_t vsource3 = src_v[uvpos * src_uvstride + (uvpos + 1)];
uint8_t ysource4 = src_y[(ypos + 1) * src_ystride + (ypos + 1)];
uint8_t usource4 = src_u[(uvpos + 1) * src_uvstride + (uvpos + 1)];
uint8_t vsource4 = src_v[(uvpos + 1) * src_uvstride + (uvpos + 1)];
if (mode_filter == 1) {
ysource = (ysource + ysource2 + ysource3 + ysource4) >> 2;
usource = (usource + usource2 + usource3 + usource4) >> 2;
vsource = (vsource + vsource2 + vsource3 + vsource4) >> 2;
}
const int is_skin = vp9_skin_pixel(ysource, usource, vsource);
for (i = 0; i < 8; i++) {
for (j = 0; j < 8; j++) {
for (i = 0; i < y_bsize; i++) {
for (j = 0; j < y_bsize; j++) {
if (is_skin)
y[i * src_ystride + j] = 255;
else
y[i * src_ystride + j] = src_y[i * src_ystride + j];
}
}
y += 8;
src_y += 8;
src_u += 4;
src_v += 4;
num_bl++;
y += y_bsize;
src_y += y_bsize;
src_u += uv_bsize;
src_v += uv_bsize;
}
y += (src_ystride << 3) - ((cm->mi_cols - 1) << 3);
src_y += (src_ystride << 3) - ((cm->mi_cols - 1) << 3);
src_u += (src_uvstride << 2) - ((cm->mi_cols - 1) << 2);
src_v += (src_uvstride << 2) - ((cm->mi_cols - 1) << 2);
y += (src_ystride << shy) - (num_bl << shy);
src_y += (src_ystride << shy) - (num_bl << shy);
src_u += (src_uvstride << shuv) - (num_bl << shuv);
src_v += (src_uvstride << shuv) - (num_bl << shuv);
}
vp9_write_yuv_frame_420(&skinmap, yuv_skinmap_file);
vpx_free_frame_buffer(&skinmap);