private static void GenerateProposals(Mat anchors, int featStride, Mat scoreBlob, Mat bboxBlob, Mat landmarkBlob, float probThreshold, IList <FaceObject> faceObjects)
{
var w = scoreBlob.W;
var h = scoreBlob.H;
// generate face proposal from bbox deltas and shifted anchors
var numAnchors = anchors.H;
for (var q = 0; q < numAnchors; q++)
{
var anchor = anchors.Row(q);
using var score = scoreBlob.Channel(q + numAnchors);
using var bbox = bboxBlob.ChannelRange(q * 4, 4);
using var landmark = landmarkBlob.ChannelRange(q * 10, 10);
// shifted anchor
var anchorY = anchor[1];
var anchorW = anchor[2] - anchor[0];
var anchorH = anchor[3] - anchor[1];
for (var i = 0; i < h; i++)
{
var anchorX = anchor[0];
for (var j = 0; j < w; j++)
{
var index = i * w + j;
var prob = score[index];
if (prob >= probThreshold)
{
// apply center size
using var mat0 = bbox.Channel(0);
using var mat1 = bbox.Channel(1);
using var mat2 = bbox.Channel(2);
using var mat3 = bbox.Channel(3);
var dx = mat0[index];
var dy = mat1[index];
var dw = mat2[index];
var dh = mat3[index];
var cx = anchorX + anchorW * 0.5f;
var cy = anchorY + anchorH * 0.5f;
var pbCx = cx + anchorW * dx;
var pbCy = cy + anchorH * dy;
var pbW = anchorW * (float)Math.Exp(dw);
var pbH = anchorH * (float)Math.Exp(dh);
var x0 = pbCx - pbW * 0.5f;
var y0 = pbCy - pbH * 0.5f;
var x1 = pbCx + pbW * 0.5f;
var y1 = pbCy + pbH * 0.5f;
var obj = new FaceObject();
obj.Rect.X = x0;
obj.Rect.Y = y0;
obj.Rect.Width = x1 - x0 + 1;
obj.Rect.Height = y1 - y0 + 1;
using var landmarkMat0 = landmark.Channel(0);
using var landmarkMat1 = landmark.Channel(1);
using var landmarkMat2 = landmark.Channel(2);
using var landmarkMat3 = landmark.Channel(3);
using var landmarkMat4 = landmark.Channel(4);
using var landmarkMat5 = landmark.Channel(5);
using var landmarkMat6 = landmark.Channel(6);
using var landmarkMat7 = landmark.Channel(7);
using var landmarkMat8 = landmark.Channel(8);
using var landmarkMat9 = landmark.Channel(9);
obj.Landmark[0].X = cx + (anchorW + 1) * landmarkMat0[index];
obj.Landmark[0].Y = cy + (anchorH + 1) * landmarkMat1[index];
obj.Landmark[1].X = cx + (anchorW + 1) * landmarkMat2[index];
obj.Landmark[1].Y = cy + (anchorH + 1) * landmarkMat3[index];
obj.Landmark[2].X = cx + (anchorW + 1) * landmarkMat4[index];
obj.Landmark[2].Y = cy + (anchorH + 1) * landmarkMat5[index];
obj.Landmark[3].X = cx + (anchorW + 1) * landmarkMat6[index];
obj.Landmark[3].Y = cy + (anchorH + 1) * landmarkMat7[index];
obj.Landmark[4].X = cx + (anchorW + 1) * landmarkMat8[index];
obj.Landmark[4].Y = cy + (anchorH + 1) * landmarkMat9[index];
obj.Prob = prob;
faceObjects.Add(obj);
}
anchorX += featStride;
}
anchorY += featStride;
}
}
}