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Use only valid values to compute mean, and use the post-warp data to avoid

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breaking on head tilt (because we were using the bounds of the rotated rect,
which included too much background).
This commit is contained in:
Andrzej Kapolka 2013-07-29 18:16:10 -07:00
parent f6d1055f00
commit 9c0e29b5e6
1 changed files with 41 additions and 21 deletions
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62
interface/src/Webcam.cpp
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@ -480,19 +480,6 @@ void FrameGrabber::grabFrame() {
_searchWindow = Rect(clip(faceBounds.tl(), imageBounds), clip(faceBounds.br(), imageBounds));
}
#ifdef HAVE_OPENNI
if (_depthGenerator.IsValid()) {
// convert from 11 to 8 bits, centered about the mean face depth (if possible)
if (_searchWindow.area() > 0) {
const double DEPTH_OFFSET_SMOOTHING = 0.95;
const double EIGHT_BIT_MIDPOINT = 128.0;
double meanOffset = EIGHT_BIT_MIDPOINT - mean(depth(_searchWindow))[0];
_depthOffset = (_depthOffset == 0.0) ? meanOffset : glm::mix(meanOffset, _depthOffset, DEPTH_OFFSET_SMOOTHING);
}
depth.convertTo(_grayDepthFrame, CV_8UC1, 1.0, _depthOffset);
}
#endif
const int ENCODED_FACE_WIDTH = 128;
const int ENCODED_FACE_HEIGHT = 128;
int combinedFaceHeight = ENCODED_FACE_HEIGHT * (depth.empty() ? 1 : 2);
@ -591,19 +578,52 @@ void FrameGrabber::grabFrame() {
uline += vpxImage.stride[2];
}
// if we have depth data, warp that and just copy it in
if (!depth.empty()) {
_faceDepth.create(ENCODED_FACE_WIDTH, ENCODED_FACE_HEIGHT, CV_8UC1);
warpAffine(_grayDepthFrame, _faceDepth, transform, _faceDepth.size());
// warp the face depth without interpolation (because it will contain invalid zero values)
_faceDepth.create(ENCODED_FACE_WIDTH, ENCODED_FACE_HEIGHT, CV_16UC1);
warpAffine(depth, _faceDepth, transform, _faceDepth.size(), INTER_NEAREST);
uchar* dline = (uchar*)_encodedFace.data() + vpxImage.stride[0] * ENCODED_FACE_HEIGHT;
uchar* src = _faceDepth.ptr();
// find the mean of the valid values
qint64 depthTotal = 0;
qint64 depthSamples = 0;
ushort* src = _faceDepth.ptr<ushort>();
for (int i = 0; i < ENCODED_FACE_HEIGHT; i++) {
uchar* dest = dline;
for (int j = 0; j < ENCODED_FACE_WIDTH; j++) {
*dest++ = *src++;
ushort depth = *src++;
if (depth != 0) {
depthTotal += depth;
depthSamples++;
}
}
dline += vpxImage.stride[0];
}
double mean = (depthSamples == 0) ? 0.0 : depthTotal / (double)depthSamples;
// update the depth offset based on the mean
const double DEPTH_OFFSET_SMOOTHING = 0.95;
const double EIGHT_BIT_MIDPOINT = 128.0;
double meanOffset = EIGHT_BIT_MIDPOINT - mean;
_depthOffset = (_depthOffset == 0.0) ? meanOffset : glm::mix(meanOffset, _depthOffset, DEPTH_OFFSET_SMOOTHING);
// convert from 11 to 8 bits for preview/local display
depth.convertTo(_grayDepthFrame, CV_8UC1, 1.0, _depthOffset);
// likewise for the encoded representation
uchar* yline = (uchar*)_encodedFace.data() + vpxImage.stride[0] * ENCODED_FACE_HEIGHT;
src = _faceDepth.ptr<ushort>();
const char UNKNOWN_DEPTH = 0;
const char MAXIMUM_DEPTH = 255;
for (int i = 0; i < ENCODED_FACE_HEIGHT; i++) {
uchar* ydest = yline;
for (int j = 0; j < ENCODED_FACE_WIDTH; j++) {
ushort depth = *src++;
if (depth == UNKNOWN_DEPTH) {
*ydest++ = MAXIMUM_DEPTH;
} else {
*ydest++ = saturate_cast<uchar>(depth + _depthOffset);
}
}
yline += vpxImage.stride[0];
}
}