[FIX] Fix Canny auto threshold

Ensure that lower ratio < upper ratio
lagadic · Oct 30, 2024 · 6adf6a0 · 6adf6a0
1 parent cc3881e
commit 6adf6a0
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/modules/core/include/visp3/core/vpImageFilter.h b/modules/core/include/visp3/core/vpImageFilter.h
@@ -351,6 +351,12 @@ class VISP_EXPORT vpImageFilter
       throw(vpException(vpException::fatalError, errMsg.str()));
     }
 
+    if (lowerThresholdRatio  >= upperThresholdRatio) {
+      std::stringstream errMsg;
+      errMsg << "Lower ratio (" << lowerThresholdRatio << ") should be lower than the upper ratio (" << upperThresholdRatio << ")";
+      throw(vpException(vpException::fatalError, errMsg.str()));
+    }
+
     vpImage<unsigned char> dI(h, w);
     vpImage<OutType> dIx(h, w), dIy(h, w);
     if ((p_dIx != nullptr) && (p_dIy != nullptr)) {
@@ -1509,6 +1515,6 @@ class VISP_EXPORT vpImageFilter
   }
 #endif
 
-};
+  };
 END_VISP_NAMESPACE
 #endif
diff --git a/modules/core/src/image/vpImageFilter_canny.cpp b/modules/core/src/image/vpImageFilter_canny.cpp
@@ -215,6 +215,12 @@ float vpImageFilter::computeCannyThreshold(const cv::Mat &cv_I, const cv::Mat *p
     throw(vpException(vpException::fatalError, errMsg.str()));
   }
 
+  if (lowerThresholdRatio  >= upperThresholdRatio) {
+    std::stringstream errMsg;
+    errMsg << "Lower ratio (" << lowerThresholdRatio << ") should be lower than the upper ratio (" << upperThresholdRatio << ")";
+    throw(vpException(vpException::fatalError, errMsg.str()));
+  }
+
   double w = cv_I.cols;
   double h = cv_I.rows;
   int bins = 256;