create color legend

Author: xmba15

README.md

@@ -149,6 +149,11 @@ wget https://github.com/Megvii-BaseDetection/YOLOX/releases/download/0.1.1rc0/yo
 ```
 
 - Test results:
+
+    +  cityscapes dataset's color legend
+
+![city scapes color legend](./data/images/cityscapes_legend.jpg)
+
     +  test result on sample image of cityscapes dataset (this model is trained on cityscapes dataset)
 ![paddleseg city scapes](./data/images/sample_city_scapes_result.jpg)
 

data/images/cityscapes_legend.jpg

@@ -46,7 +46,10 @@ int main(int argc, char* argv[])
                            Ort::SemanticSegmentationPaddleSegBisenetv2::IMG_W);
 
     auto result = processOneFrame(osh, img, dst.data());
-    cv::imwrite("result.jpg", result);
+    cv::Mat legend = drawColorChart(Ort::CITY_SCAPES_CLASSES, COLORS);
+    cv::imshow("legend", legend);
+    cv::imshow("overlaid result", result);
+    cv::waitKey(0);
 
     return EXIT_SUCCESS;
 }

examples/SemanticSegmentationPaddleSegBisenetv2App.cpp

@@ -30,7 +30,7 @@ inline std::vector<cv::Scalar> toCvScalarColors(const std::vector<std::array<int
 }
 
 inline cv::Mat visualizeOneImage(const cv::Mat& img, const std::vector<std::array<float, 4>>& bboxes,
-                                 const std::vector<uint64_t>& classIndices, const std::vector<cv::Scalar> allColors,
+                                 const std::vector<uint64_t>& classIndices, const std::vector<cv::Scalar>& allColors,
                                  const std::vector<std::string>& allClassNames = {})
 {
     assert(bboxes.size() == classIndices.size());
@@ -63,7 +63,7 @@ inline cv::Mat visualizeOneImage(const cv::Mat& img, const std::vector<std::arra
 
 inline cv::Mat visualizeOneImageWithMask(const cv::Mat& img, const std::vector<std::array<float, 4>>& bboxes,
                                          const std::vector<uint64_t>& classIndices, const std::vector<cv::Mat>& masks,
-                                         const std::vector<cv::Scalar> allColors,
+                                         const std::vector<cv::Scalar>& allColors,
                                          const std::vector<std::string>& allClassNames = {},
                                          const float maskThreshold = 0.5)
 {
@@ -116,4 +116,16 @@ inline cv::Mat visualizeOneImageWithMask(const cv::Mat& img, const std::vector<s
 
     return result;
 }
+
+cv::Mat drawColorChart(const std::vector<std::string>& classes, const std::vector<cv::Scalar>& colors)
+{
+    cv::Mat legend = cv::Mat::zeros((classes.size() * 25) + 25, 300, CV_8UC(3));
+    for (std::size_t i = 0; i < classes.size(); ++i) {
+        cv::putText(legend, classes[i], cv::Point(5, (i * 25) + 17), cv::FONT_HERSHEY_SIMPLEX, 0.5,
+                    cv::Scalar(0, 0, 255), 2);
+        cv::rectangle(legend, cv::Point(100, (i * 25)), cv::Point(300, (i * 25) + 25), colors[i], -1);
+    }
+
+    return legend;
+}
 }  // namespace