Merge pull request opencv#13837 from amithjkamath:test

New computeECC function, and updated findTransformECC function to make gaussian filtering optional (opencv#13837)

* fix for opencv#12432 with doc and tests

* Added doc string for new parameter.

* Fixes suggested by Alalek for getting around ABI incompatibility.

* Update to docstring, to remove parameter that isn't relevant.

* More updates based on Alalek's usggestions.

modules/video/include/opencv2/video/tracking.hpp

@@ -265,6 +265,19 @@ enum
     MOTION_HOMOGRAPHY  = 3
 };
 
+/** @brief Computes the Enhanced Correlation Coefficient value between two images @cite EP08 .
+
+@param templateImage single-channel template image; CV_8U or CV_32F array.
+@param inputImage single-channel input image to be warped to provide an image similar to
+ templateImage, same type as templateImage.
+@param inputMask An optional mask to indicate valid values of inputImage.
+
+@sa
+findTransformECC
+ */
+
+CV_EXPORTS_W double computeECC(InputArray templateImage, InputArray inputImage, InputArray inputMask = noArray());
+
 /** @example samples/cpp/image_alignment.cpp
 An example using the image alignment ECC algorithm
 */
@@ -273,7 +286,7 @@ An example using the image alignment ECC algorithm
 
 @param templateImage single-channel template image; CV_8U or CV_32F array.
 @param inputImage single-channel input image which should be warped with the final warpMatrix in
-order to provide an image similar to templateImage, same type as temlateImage.
+order to provide an image similar to templateImage, same type as templateImage.
 @param warpMatrix floating-point \f$2\times 3\f$ or \f$3\times 3\f$ mapping matrix (warp).
 @param motionType parameter, specifying the type of motion:
  -   **MOTION_TRANSLATION** sets a translational motion model; warpMatrix is \f$2\times 3\f$ with
@@ -290,6 +303,7 @@ criteria.epsilon defines the threshold of the increment in the correlation coeff
 iterations (a negative criteria.epsilon makes criteria.maxcount the only termination criterion).
 Default values are shown in the declaration above.
 @param inputMask An optional mask to indicate valid values of inputImage.
+@param gaussFiltSize An optional value indicating size of gaussian blur filter; (DEFAULT: 5)
 
 The function estimates the optimum transformation (warpMatrix) with respect to ECC criterion
 (@cite EP08), that is
@@ -317,12 +331,19 @@ sample image_alignment.cpp that demonstrates the use of the function. Note that
 an exception if algorithm does not converges.
 
 @sa
-estimateAffine2D, estimateAffinePartial2D, findHomography
+computeECC, estimateAffine2D, estimateAffinePartial2D, findHomography
  */
 CV_EXPORTS_W double findTransformECC( InputArray templateImage, InputArray inputImage,
-                                      InputOutputArray warpMatrix, int motionType = MOTION_AFFINE,
-                                      TermCriteria criteria = TermCriteria(TermCriteria::COUNT+TermCriteria::EPS, 50, 0.001),
-                                      InputArray inputMask = noArray());
+                                      InputOutputArray warpMatrix, int motionType,
+                                      TermCriteria criteria,
+                                      InputArray inputMask, int gaussFiltSize);
+
+/** @overload */
+CV_EXPORTS
+double findTransformECC(InputArray templateImage, InputArray inputImage,
+    InputOutputArray warpMatrix, int motionType = MOTION_AFFINE,
+    TermCriteria criteria = TermCriteria(TermCriteria::COUNT+TermCriteria::EPS, 50, 0.001),
+    InputArray inputMask = noArray());
 
 /** @example samples/cpp/kalman.cpp
 An example using the standard Kalman filter

modules/video/src/ecc.cpp

@@ -309,16 +309,48 @@ static void update_warping_matrix_ECC (Mat& map_matrix, const Mat& update, const
 }
 
 
+/** Function that computes enhanced corelation coefficient from Georgios et.al. 2008
+*   See https://github.com/opencv/opencv/issues/12432
+*/
+double cv::computeECC(InputArray templateImage, InputArray inputImage, InputArray inputMask)
+{
+    CV_Assert(!templateImage.empty());
+    CV_Assert(!inputImage.empty());
+
+    if( ! (templateImage.type()==inputImage.type()))
+        CV_Error( Error::StsUnmatchedFormats, "Both input images must have the same data type" );
+
+    Scalar meanTemplate, sdTemplate;
+
+    int active_pixels = inputMask.empty() ? templateImage.size().area() : countNonZero(inputMask);
+
+    meanStdDev(templateImage, meanTemplate, sdTemplate, inputMask);
+    Mat templateImage_zeromean = Mat::zeros(templateImage.size(), templateImage.type());
+    subtract(templateImage, meanTemplate, templateImage_zeromean, inputMask);
+    double templateImagenorm = std::sqrt(active_pixels*sdTemplate.val[0]*sdTemplate.val[0]);
+
+    Scalar meanInput, sdInput;
+
+    Mat inputImage_zeromean = Mat::zeros(inputImage.size(), inputImage.type());
+    meanStdDev(inputImage, meanInput, sdInput, inputMask);
+    subtract(inputImage, meanInput, inputImage_zeromean, inputMask);
+    double inputImagenorm = std::sqrt(active_pixels*sdInput.val[0]*sdInput.val[0]);
+
+    return templateImage_zeromean.dot(inputImage_zeromean)/(templateImagenorm*inputImagenorm);
+}
+
+
 double cv::findTransformECC(InputArray templateImage,
                             InputArray inputImage,
                             InputOutputArray warpMatrix,
                             int motionType,
                             TermCriteria criteria,
-                            InputArray inputMask)
+                            InputArray inputMask,
+                            int gaussFiltSize)
 {
 
 
-    Mat src = templateImage.getMat();//template iamge
+    Mat src = templateImage.getMat();//template image
     Mat dst = inputImage.getMat(); //input image (to be warped)
     Mat map = warpMatrix.getMat(); //warp (transformation)
 
@@ -416,19 +448,19 @@ double cv::findTransformECC(InputArray templateImage,
 
     //gaussian filtering is optional
     src.convertTo(templateFloat, templateFloat.type());
-    GaussianBlur(templateFloat, templateFloat, Size(5, 5), 0, 0);
+    GaussianBlur(templateFloat, templateFloat, Size(gaussFiltSize, gaussFiltSize), 0, 0);
 
     Mat preMaskFloat;
     preMask.convertTo(preMaskFloat, CV_32F);
-    GaussianBlur(preMaskFloat, preMaskFloat, Size(5, 5), 0, 0);
+    GaussianBlur(preMaskFloat, preMaskFloat, Size(gaussFiltSize, gaussFiltSize), 0, 0);
     // Change threshold.
     preMaskFloat *= (0.5/0.95);
     // Rounding conversion.
     preMaskFloat.convertTo(preMask, preMask.type());
     preMask.convertTo(preMaskFloat, preMaskFloat.type());
 
     dst.convertTo(imageFloat, imageFloat.type());
-    GaussianBlur(imageFloat, imageFloat, Size(5, 5), 0, 0);
+    GaussianBlur(imageFloat, imageFloat, Size(gaussFiltSize, gaussFiltSize), 0, 0);
 
     // needed matrices for gradients and warped gradients
     Mat gradientX = Mat::zeros(hd, wd, CV_32FC1);
@@ -557,5 +589,13 @@ double cv::findTransformECC(InputArray templateImage,
     return rho;
 }
 
+double cv::findTransformECC(InputArray templateImage, InputArray inputImage,
+    InputOutputArray warpMatrix, int motionType,
+    TermCriteria criteria,
+    InputArray inputMask)
+{
+    // Use default value of 5 for gaussFiltSize to maintain backward compatibility.
+    return findTransformECC(templateImage, inputImage, warpMatrix, motionType, criteria, inputMask, 5);
+}
 
 /* End of file. */

modules/video/test/test_ecc.cpp

@@ -95,7 +95,6 @@ double CV_ECC_BaseTest::computeRMS(const Mat& mat1, const Mat& mat2){
     return sqrt(errorMat.dot(errorMat)/(mat1.rows*mat1.cols));
 }
 
-
 class CV_ECC_Test_Translation : public CV_ECC_BaseTest
 {
 public:
@@ -464,6 +463,22 @@ bool CV_ECC_Test_Mask::testMask(int from)
             return false;
         }
 
+        // Test with non-default gaussian blur.
+        findTransformECC(warpedImage, testImg, mapTranslation, 0,
+            TermCriteria(TermCriteria::COUNT+TermCriteria::EPS, ECC_iterations, ECC_epsilon), mask, 1);
+
+        if (!isMapCorrect(mapTranslation)){
+            ts->set_failed_test_info(cvtest::TS::FAIL_INVALID_OUTPUT);
+            return false;
+        }
+
+        if (computeRMS(mapTranslation, translationGround)>MAX_RMS_ECC){
+            ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
+            ts->printf( ts->LOG, "RMS = %f",
+                computeRMS(mapTranslation, translationGround));
+            return false;
+        }
+
     }
     return true;
 }
@@ -476,6 +491,16 @@ void CV_ECC_Test_Mask::run(int from)
     ts->set_failed_test_info(cvtest::TS::OK);
 }
 
+TEST(Video_ECC_Test_Compute, accuracy)
+{
+    Mat testImg = (Mat_<float>(3, 3) << 1, 0, 0, 1, 0, 0, 1, 0, 0);
+    Mat warpedImage = (Mat_<float>(3, 3) << 0, 1, 0, 0, 1, 0, 0, 1, 0);
+    Mat_<unsigned char> mask = Mat_<unsigned char>::ones(testImg.rows, testImg.cols);
+    double ecc = computeECC(warpedImage, testImg, mask);
+
+    EXPECT_NEAR(ecc, -0.5f, 1e-5f);
+}
+
 TEST(Video_ECC_Translation, accuracy) { CV_ECC_Test_Translation test; test.safe_run();}
 TEST(Video_ECC_Euclidean, accuracy) { CV_ECC_Test_Euclidean test; test.safe_run(); }
 TEST(Video_ECC_Affine, accuracy) { CV_ECC_Test_Affine test; test.safe_run(); }