C++ tutorial API only cv::imshow if not empty

doc/modules/python_module.md

@@ -106,6 +106,11 @@ Windows:
 
 
 ## Common Issues
+### Do not use PIL
+In order to read images in Python, make sure to use OpenCV (do not use PIL). We found that feeding a PIL image format to OpenPose results in the input image appearing in grey and duplicated 9 times (so the output skeleton appear 3 times smaller than they should be, and duplicated 9 times).
+
+
+### Cannot Import Name PyOpenPose
 The error in general is that PyOpenPose cannot be found (an error similar to: `ImportError: cannot import name pyopenpose`). Ensure first that `BUILD_PYTHON` flag is set to ON. If the error persists, check the following:
 
 In the script you are running, check for the following line, and run the following command in the same location as where the file is

doc/release_notes.md

@@ -419,6 +419,7 @@ OpenPose Library - Release Notes
 2. Functions or parameters renamed:
 3. Main bugs fixed:
     1. 90 and 270-degree rotations working again.
+    2. C++ tutorial API demos only try to cv::imshow the image if it is not empty (avoding the assert that it would trigger otherwise).
 4. Changes/additions that affect the compatibility with the OpenPose Unity Plugin:
 
 

examples/tutorial_api_cpp/01_body_from_image_default.cpp

@@ -29,8 +29,13 @@ void display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-            cv::waitKey(0);
+            if (!cvMat.empty())
+            {
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                cv::waitKey(0);
+            }
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/02_whole_body_from_image_default.cpp

@@ -29,8 +29,13 @@ void display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-            cv::waitKey(0);
+            if (!cvMat.empty())
+            {
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                cv::waitKey(0);
+            }
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/03_keypoints_from_image.cpp

@@ -31,8 +31,13 @@ void display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-            cv::waitKey(0);
+            if (!cvMat.empty())
+            {
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                cv::waitKey(0);
+            }
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/04_keypoints_from_images.cpp

@@ -31,7 +31,10 @@ bool display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+            if (!cvMat.empty())
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/05_keypoints_from_images_multi_gpu.cpp

@@ -37,7 +37,10 @@ bool display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+            if (!cvMat.empty())
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/06_face_from_image.cpp

@@ -34,8 +34,13 @@ void display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-            cv::waitKey(0);
+            if (!cvMat.empty())
+            {
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                cv::waitKey(0);
+            }
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/07_hand_from_image.cpp

@@ -34,8 +34,13 @@ void display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-            cv::waitKey(0);
+            if (!cvMat.empty())
+            {
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                cv::waitKey(0);
+            }
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/08_heatmaps_from_image.cpp

@@ -57,7 +57,10 @@ bool display(
             cv::applyColorMap(desiredChannelHeatMapUint8, desiredChannelHeatMapUint8, cv::COLORMAP_JET);
             cv::addWeighted(netInputImageUint8, 0.5, desiredChannelHeatMapUint8, 0.5, 0., imageToRender);
             // Display image
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", imageToRender);
+            if (!imageToRender.empty())
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", imageToRender);
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/09_keypoints_from_heatmaps.cpp

@@ -34,8 +34,13 @@ void display(const std::shared_ptr<std::vector<std::shared_ptr<op::Datum>>>& dat
         {
             // Display image
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-            cv::waitKey(0);
+            if (!cvMat.empty())
+            {
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                cv::waitKey(0);
+            }
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/12_asynchronous_custom_output.cpp

@@ -28,7 +28,10 @@ public:
         {
             // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
             const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-            cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+            if (!cvMat.empty())
+                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+            else
+                op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
         }
         else
             op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/13_asynchronous_custom_input_output_and_datum.cpp

@@ -110,7 +110,10 @@ public:
             {
                 // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
                 const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-                cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                if (!cvMat.empty())
+                    cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                else
+                    op::opLog("Empty cv::Mat as output.", op::Priority::High);
             }
             else
                 op::opLog("Nullptr or empty datumsPtr found.", op::Priority::High);

examples/tutorial_api_cpp/17_synchronous_custom_output.cpp

@@ -82,11 +82,16 @@ public:
                 {
                     // Display rendered output image
                     const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-                    cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-                    // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
-                    const char key = (char)cv::waitKey(1);
-                    if (key == 27)
-                        this->stop();
+                    if (!cvMat.empty())
+                    {
+                        cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                        // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
+                        const char key = (char)cv::waitKey(1);
+                        if (key == 27)
+                            this->stop();
+                    }
+                    else
+                        op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
                 }
             }
         }

examples/tutorial_api_cpp/18_synchronous_custom_all_and_datum.cpp

@@ -204,11 +204,16 @@ public:
                 {
                     // Display rendered output image
                     const cv::Mat cvMat = OP_OP2CVCONSTMAT(datumsPtr->at(0)->cvOutputData);
-                    cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
-                    // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
-                    const char key = (char)cv::waitKey(1);
-                    if (key == 27)
-                        this->stop();
+                    if (!cvMat.empty())
+                    {
+                        cv::imshow(OPEN_POSE_NAME_AND_VERSION + " - Tutorial C++ API", cvMat);
+                        // Display image and sleeps at least 1 ms (it usually sleeps ~5-10 msec to display the image)
+                        const char key = (char)cv::waitKey(1);
+                        if (key == 27)
+                            this->stop();
+                    }
+                    else
+                        op::opLog("Empty cv::Mat as output.", op::Priority::High, __LINE__, __FUNCTION__, __FILE__);
                 }
             }
         }