Merge pull request #19640 An error occurred from alalek:issue_19639

calib3d(usac): do not crash on empty models

* calib3d(test): regression test for issue 19639

* calib3d(usac): do not crash in setModelParameters()

* calib3d(usac): handle empty models in isModelGood()

modules/calib3d/src/usac/estimator.cpp

@@ -236,13 +236,18 @@ public:
         CV_DbgAssert(points);
     }
 
-    inline void setModelParameters (const Mat &model) override {
+    inline void setModelParameters(const Mat& model) override
+    {
+        CV_Assert(!model.empty());
+        CV_CheckTypeEQ(model.depth(), CV_64F, "");
+
         const auto * const m = (double *) model.data;
         m11=static_cast<float>(m[0]); m12=static_cast<float>(m[1]); m13=static_cast<float>(m[2]);
         m21=static_cast<float>(m[3]); m22=static_cast<float>(m[4]); m23=static_cast<float>(m[5]);
         m31=static_cast<float>(m[6]); m32=static_cast<float>(m[7]); m33=static_cast<float>(m[8]);
 
         const Mat model_inv = model.inv();
+        CV_CheckTypeEQ(model_inv.depth(), CV_64F, "");
         const auto * const minv = (double *) model_inv.data;
         minv11=(float)minv[0]; minv12=(float)minv[1]; minv13=(float)minv[2];
         minv21=(float)minv[3]; minv22=(float)minv[4]; minv23=(float)minv[5];
@@ -299,7 +304,11 @@ public:
         CV_DbgAssert(points);
     }
 
-    inline void setModelParameters (const Mat &model) override {
+    inline void setModelParameters(const Mat& model) override
+    {
+        CV_Assert(!model.empty());
+        CV_CheckTypeEQ(model.depth(), CV_64F, "");
+
         const auto * const m = (double *) model.data;
         m11=static_cast<float>(m[0]); m12=static_cast<float>(m[1]); m13=static_cast<float>(m[2]);
         m21=static_cast<float>(m[3]); m22=static_cast<float>(m[4]); m23=static_cast<float>(m[5]);
@@ -349,7 +358,11 @@ public:
         CV_DbgAssert(points);
     }
 
-    inline void setModelParameters (const Mat &model) override {
+    inline void setModelParameters(const Mat& model) override
+    {
+        CV_Assert(!model.empty());
+        CV_CheckTypeEQ(model.depth(), CV_64F, "");
+
         const auto * const m = (double *) model.data;
         m11=static_cast<float>(m[0]); m12=static_cast<float>(m[1]); m13=static_cast<float>(m[2]);
         m21=static_cast<float>(m[3]); m22=static_cast<float>(m[4]); m23=static_cast<float>(m[5]);
@@ -416,7 +429,11 @@ public:
         CV_DbgAssert(points);
     }
 
-    inline void setModelParameters (const Mat &model) override {
+    inline void setModelParameters(const Mat& model) override
+    {
+        CV_Assert(!model.empty());
+        CV_CheckTypeEQ(model.depth(), CV_64F, "");
+
         const auto * const m = (double *) model.data;
         m11=static_cast<float>(m[0]); m12=static_cast<float>(m[1]); m13=static_cast<float>(m[2]);
         m21=static_cast<float>(m[3]); m22=static_cast<float>(m[4]); m23=static_cast<float>(m[5]);
@@ -476,7 +493,11 @@ public:
     }
 
 
-    inline void setModelParameters (const Mat &model) override {
+    inline void setModelParameters (const Mat& model) override
+    {
+        CV_Assert(!model.empty());
+        CV_CheckTypeEQ(model.depth(), CV_64F, "");
+
         const auto * const p = (double *) model.data;
         p11 = (float)p[0]; p12 = (float)p[1]; p13 = (float)p[2];  p14 = (float)p[3];
         p21 = (float)p[4]; p22 = (float)p[5]; p23 = (float)p[6];  p24 = (float)p[7];
@@ -535,7 +556,11 @@ public:
         CV_DbgAssert(points);
     }
 
-    inline void setModelParameters (const Mat &model) override {
+    inline void setModelParameters(const Mat& model) override
+    {
+        CV_Assert(!model.empty());
+        CV_CheckTypeEQ(model.depth(), CV_64F, "");
+
         const auto * const m = (double *) model.data;
         m11 = (float)m[0]; m12 = (float)m[1]; m13 = (float)m[2];
         m21 = (float)m[3]; m22 = (float)m[4]; m23 = (float)m[5];

modules/calib3d/src/usac/quality.cpp

@@ -421,7 +421,11 @@ public:
      * @current_hypothesis: current RANSAC iteration
      * Return: true if model is good, false - otherwise.
      */
-    inline bool isModelGood (const Mat &model) override {
+    inline bool isModelGood(const Mat& model) override
+    {
+        if (model.empty())
+            return false;
+
         // update error object with current model
         err->setModelParameters(model);
 
@@ -584,4 +588,4 @@ Ptr<SPRT> SPRT::create (int state, const Ptr<Error> &err_, int points_size_,
     return makePtr<SPRTImpl>(state, err_, points_size_, inlier_threshold_,
        prob_pt_of_good_model, prob_pt_of_bad_model, time_sample, avg_num_models, score_type_);
 }
-}}
+}}

modules/calib3d/test/test_usac.cpp

@@ -4,7 +4,8 @@
 
 #include "test_precomp.hpp"
 
-namespace opencv_test {
+namespace opencv_test { namespace {
+
 enum TestSolver { Homogr, Fundam, Essen, PnP, Affine};
 /*
 * rng -- reference to random generator
@@ -264,7 +265,40 @@ TEST(usac_Fundamental, accuracy) {
                                                            int(max_iters), mask);
             checkInliersMask(TestSolver::Fundam, inl_size, thr, pts1, pts2, F, mask);
         }
-    }}
+    }
+}
+
+TEST(usac_Fundamental, regression_19639)
+{
+    double x_[] = {
+        941, 890,
+        596, 940,
+        898, 941,
+        894, 933,
+        586, 938,
+        902, 933,
+        887, 935
+    };
+    Mat x(7, 1, CV_64FC2, x_);
+
+    double y_[] = {
+        1416,  806,
+        1157,  852,
+        1380,  855,
+        1378,  843,
+        1145,  849,
+        1378,  843,
+        1378,  843
+    };
+    Mat y(7, 1, CV_64FC2, y_);
+
+    //std::cout << x << std::endl;
+    //std::cout << y << std::endl;
+
+    Mat m = cv::findFundamentalMat(x, y, USAC_MAGSAC, 3, 0.99);
+    EXPECT_TRUE(m.empty());
+}
+
 
 TEST(usac_Essential, accuracy) {
     std::vector<int> gt_inliers;
@@ -405,4 +439,5 @@ TEST(usac_testUsacParams, accuracy) {
     checkInliersMask(TestSolver::Homogr, inl_size, usac_params.threshold, pts1, pts2, model, mask);
 }
 
-}
+
+}}  // namespace