日本中二少年教你用姿勢估計把自己變成3D人物，動作實時同步，iOS上也能實現

// Properties for onnx and estimation
    private Net Onnx;
    private Mat[] outputs = new Mat[4];

    private const int inputImageSize = 224;
    private const int JointNum = 24;
    private const int HeatMapCol = 14;
    private const int HeatMapCol_Squared = 14 * 14;
    private const int HeatMapCol_Cube = 14 * 14 * 14;

    char[] heatMap2Dbuf = new char[JointNum * HeatMapCol_Squared * 4];
    float[] heatMap2D = new float[JointNum * HeatMapCol_Squared];
    char[] offset2Dbuf = new char[JointNum * HeatMapCol_Squared * 2 * 4];
    float[] offset2D = new float[JointNum * HeatMapCol_Squared * 2];

    char[] heatMap3Dbuf = new char[JointNum * HeatMapCol_Cube * 4];
    float[] heatMap3D = new float[JointNum * HeatMapCol_Cube];
    char[] offset3Dbuf = new char[JointNum * HeatMapCol_Cube * 3 * 4];
    float[] offset3D = new float[JointNum * HeatMapCol_Cube * 3];

    public void InitONNX()
    {
        Onnx = Net.ReadNetFromONNX(Application.dataPath + @"\MobileNet3D2.onnx");
        for (var i = 0; i < 4; i++) outputs[i] = new Mat();
    }

    /// <summary>
    /// Predict
    /// </summary>
    /// <param name="img"></param>
    public void Predict(Mat img)
    {
        var blob = CvDnn.BlobFromImage(img, 1.0 / 255.0, new OpenCvSharp.Size(inputImageSize, inputImageSize), 0.0, false, false);
        Onnx.SetInput(blob);
        Onnx.Forward(outputs, new string[] { "369", "373", "361", "365" });

        // copy 2D outputs
        Marshal.Copy(outputs[2].Data, heatMap2Dbuf, 0, heatMap2Dbuf.Length);
        Buffer.BlockCopy(heatMap2Dbuf, 0, heatMap2D, 0, heatMap2Dbuf.Length);
        Marshal.Copy(outputs[3].Data, offset2Dbuf, 0, offset2Dbuf.Length);
        Buffer.BlockCopy(offset2Dbuf, 0, offset2D, 0, offset2Dbuf.Length);
        for (var j = 0; j < JointNum; j++)
        {
            var maxXIndex = 0;
            var maxYIndex = 0;
            jointPoints[j].score2D = 0.0f;
            for (var y = 0; y < HeatMapCol; y++)
            {
                for (var x = 0; x < HeatMapCol; x++)
                {
                    var l = new List<int>();
                    var v = heatMap2D[(HeatMapCol_Squared) * j + HeatMapCol * y + x];

                    if (v > jointPoints[j].score2D)
                    {
                        jointPoints[j].score2D = v;
                        maxXIndex = x;
                        maxYIndex = y;
                    }
                }

            }

            jointPoints[j].Pos2D.x = (offset2D[HeatMapCol_Squared * j + HeatMapCol * maxYIndex + maxXIndex] + maxXIndex / (float)HeatMapCol) * (float)inputImageSize;
            jointPoints[j].Pos2D.y = (offset2D[HeatMapCol_Squared * (j + JointNum) + HeatMapCol * maxYIndex + maxXIndex] + maxYIndex / (float)HeatMapCol) * (float)inputImageSize;
        }

        // copy 3D outputs
        Marshal.Copy(outputs[0].Data, heatMap3Dbuf, 0, heatMap3Dbuf.Length);
        Buffer.BlockCopy(heatMap3Dbuf, 0, heatMap3D, 0, heatMap3Dbuf.Length);
        Marshal.Copy(outputs[1].Data, offset3Dbuf, 0, offset3Dbuf.Length);
        Buffer.BlockCopy(offset3Dbuf, 0, offset3D, 0, offset3Dbuf.Length);
        for (var j = 0; j < JointNum; j++)
        {
            var maxXIndex = 0;
            var maxYIndex = 0;
            var maxZIndex = 0;
            jointPoints[j].score3D = 0.0f;
            for (var z = 0; z < HeatMapCol; z++)
            {
                for (var y = 0; y < HeatMapCol; y++)
                {
                    for (var x = 0; x < HeatMapCol; x++)
                    {
                        float v = heatMap3D[HeatMapCol_Cube * j + HeatMapCol_Squared * z + HeatMapCol * y + x];
                        if (v > jointPoints[j].score3D)
                        {
                            jointPoints[j].score3D = v;
                            maxXIndex = x;
                            maxYIndex = y;
                            maxZIndex = z;
                        }
                    }
                }
            }

            jointPoints[j].Now3D.x = (offset3D[HeatMapCol_Cube * j + HeatMapCol_Squared * maxZIndex + HeatMapCol * maxYIndex + maxXIndex] + (float)maxXIndex / (float)HeatMapCol) * (float)inputImageSize;
            jointPoints[j].Now3D.y = (float)inputImageSize - (offset3D[HeatMapCol_Cube * (j + JointNum) + HeatMapCol_Squared * maxZIndex + HeatMapCol * maxYIndex + maxXIndex] + (float)maxYIndex / (float)HeatMapCol) * (float)inputImageSize;
            jointPoints[j].Now3D.z = (offset3D[HeatMapCol_Cube * (j + JointNum * 2) + HeatMapCol_Squared * maxZIndex + HeatMapCol * maxYIndex + maxXIndex] + (float)(maxZIndex - 7) / (float)HeatMapCol) * (float)inputImageSize;
        }
    }