opencv - 如何正确检查H矩阵的有效性

Question

我正在使用 SIFT 算法进行图像匹配，并计算单应矩阵以了解对象和场景之间是否存在有效的对应关系。下面发布的方法“isValidHMatrix”是我如何检查 H 矩阵是否良好，正如在这个问题中发布的那样，我计算 H 矩阵中左上角 2x2 矩阵的行列式，如果行列式 >= 0 那么否则 H 矩阵不好是好的。

但是当我应用该概念来查找某些对象和场景之间的匹配时，我得到了以下发布的图像结果：

请让我知道如何正确检查 H 矩阵的有效性

结果：

for image 1: the object is part of the scene, but i got "invalid HMatrix,   
det(H): -8.978588811689873" 

for image 2: the object is not part of the scene, but i got "valid HMatrix, 
det(H): 3.32362768456779" 

for image 3: the object is not part of the scene, but i got 
"goodMatchesList.size() < 4 points" 

for image 4: the object is part of the scene, but i got "valid HMatrix, 
det(H): 0.153917265625088" 

for image 5: the object is part of the scene, but i got "valid HMatrix, 
det(H): 1.0012971075010808" 

for image 6: the object is part of the scene, but i got "valid HMatrix, 
det(H): 0.0037162733516824488" 

for image 7: the object is not part of the scene, but i got "invalid 
HMatrix, det(H): -2.397038481177457E-6" 

for image 8: the object is not part of the scene, but i got "valid HMatrix, 
det(H): 0.0" 

代码：

private boolean isValidHMatrix(Mat hMatrix, String token) {
    // TODO Auto-generated method stub
    //double det = Core.determinant(hMatrix);
    double det = Core.determinant(hMatrix.submat(new Rect (new Point(0, 0), new Point(2, 2))));

    if (det >= 0) {
        Log.V(TAG, "isValidHMatrix", token+"_valid HMatrix, det(H): "+det);
        return true;
    } else {
        Log.V(TAG, "isValidHMatrix", token+"_invalid HMatrix, det(H): "+det);
        return false;
    }

}