MLECO-929 Add Object Detection sample application using the public ArmNN C++ API
Change-Id: I14aa1b4b726212cffbefd6687203f93f936fa872
Signed-off-by: Éanna Ó Catháin <eanna.ocathain@arm.com>
diff --git a/samples/ObjectDetection/src/SSDResultDecoder.cpp b/samples/ObjectDetection/src/SSDResultDecoder.cpp
new file mode 100644
index 0000000..a331921
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+++ b/samples/ObjectDetection/src/SSDResultDecoder.cpp
@@ -0,0 +1,80 @@
+//
+// Copyright © 2020 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "SSDResultDecoder.hpp"
+
+#include <cassert>
+#include <algorithm>
+#include <cmath>
+#include <stdexcept>
+namespace od
+{
+
+DetectedObjects SSDResultDecoder::Decode(const InferenceResults& networkResults,
+ const Size& outputFrameSize,
+ const Size& resizedFrameSize,
+ const std::vector<std::string>& labels)
+{
+ // SSD network outputs 4 tensors: bounding boxes, labels, probabilities, number of detections.
+ if (networkResults.size() != 4)
+ {
+ throw std::runtime_error("Number of outputs from SSD model doesn't equal 4");
+ }
+
+ DetectedObjects detectedObjects;
+ const int numDetections = static_cast<int>(std::lround(networkResults[3][0]));
+
+ double longEdgeInput = std::max(resizedFrameSize.m_Width, resizedFrameSize.m_Height);
+ double longEdgeOutput = std::max(outputFrameSize.m_Width, outputFrameSize.m_Height);
+ const double resizeFactor = longEdgeOutput/longEdgeInput;
+
+ for (int i=0; i<numDetections; ++i)
+ {
+ if (networkResults[2][i] > m_objectThreshold)
+ {
+ DetectedObject detectedObject;
+ detectedObject.SetScore(networkResults[2][i]);
+ auto classId = std::lround(networkResults[1][i]);
+
+ if (classId < labels.size())
+ {
+ detectedObject.SetLabel(labels[classId]);
+ }
+ else
+ {
+ detectedObject.SetLabel(std::to_string(classId));
+ }
+ detectedObject.SetId(classId);
+
+ // Convert SSD bbox outputs (ratios of image size) to pixel values.
+ double topLeftY = networkResults[0][i*4 + 0] * resizedFrameSize.m_Height;
+ double topLeftX = networkResults[0][i*4 + 1] * resizedFrameSize.m_Width;
+ double botRightY = networkResults[0][i*4 + 2] * resizedFrameSize.m_Height;
+ double botRightX = networkResults[0][i*4 + 3] * resizedFrameSize.m_Width;
+
+ // Scale the coordinates to output frame size.
+ topLeftY *= resizeFactor;
+ topLeftX *= resizeFactor;
+ botRightY *= resizeFactor;
+ botRightX *= resizeFactor;
+
+ assert(botRightX > topLeftX);
+ assert(botRightY > topLeftY);
+
+ // Internal BoundingBox stores box top left x,y and width, height.
+ detectedObject.SetBoundingBox({static_cast<int>(std::round(topLeftX)),
+ static_cast<int>(std::round(topLeftY)),
+ static_cast<unsigned int>(botRightX - topLeftX),
+ static_cast<unsigned int>(botRightY - topLeftY)});
+
+ detectedObjects.emplace_back(detectedObject);
+ }
+ }
+ return detectedObjects;
+}
+
+SSDResultDecoder::SSDResultDecoder(float ObjectThreshold) : m_objectThreshold(ObjectThreshold) {}
+
+}// namespace od
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