From 0981367e842c8dfd0ba1b7e6c646a4bd78fa1213 Mon Sep 17 00:00:00 2001
From: MediaPipe Team <mediapipe-team@google.com>
Date: Thu, 23 Feb 2023 14:09:26 -0800
Subject: [PATCH] DetectionTransformationCalculator handles empty input.

PiperOrigin-RevId: 511881969
---
 .../detection_transformation_calculator.cc    |  3 ++
 ...etection_transformation_calculator_test.cc | 36 +++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/mediapipe/calculators/util/detection_transformation_calculator.cc b/mediapipe/calculators/util/detection_transformation_calculator.cc
index 43030dbe..3eac315f 100644
--- a/mediapipe/calculators/util/detection_transformation_calculator.cc
+++ b/mediapipe/calculators/util/detection_transformation_calculator.cc
@@ -227,6 +227,9 @@ class DetectionTransformationCalculator : public Node {
     std::pair<int, int> image_size = kInImageSize(cc).Get();
     std::vector<Detection> transformed_detections;
     LocationData::Format input_location_data_format;
+    if (kInDetections(cc).IsEmpty() && kInDetection(cc).IsEmpty()) {
+      return absl::OkStatus();
+    }
     if (kInDetections(cc).IsConnected()) {
       transformed_detections = kInDetections(cc).Visit(
           [&](const DetectionList& detection_list) {
diff --git a/mediapipe/calculators/util/detection_transformation_calculator_test.cc b/mediapipe/calculators/util/detection_transformation_calculator_test.cc
index 48291b2d..e280b515 100644
--- a/mediapipe/calculators/util/detection_transformation_calculator_test.cc
+++ b/mediapipe/calculators/util/detection_transformation_calculator_test.cc
@@ -161,6 +161,42 @@ TEST(DetectionsTransformationCalculatorTest, WrongLocationDataFormat) {
                                  "RELATIVE_BOUNDING_BOX or BOUNDING_BOX"));
 }
 
+TEST(DetectionsTransformationCalculatorTest, EmptyDetection) {
+  CalculatorRunner runner(ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"pb(
+    calculator: "DetectionTransformationCalculator"
+    input_stream: "DETECTION:input_detection"
+    input_stream: "IMAGE_SIZE:image_size"
+    output_stream: "PIXEL_DETECTION:output_detection"
+  )pb"));
+
+  std::pair<int, int> image_size({2000, 1000});
+  runner.MutableInputs()
+      ->Tag(kImageSizeTag)
+      .packets.push_back(
+          MakePacket<std::pair<int, int>>(image_size).At(Timestamp(0)));
+
+  auto status = runner.Run();
+  ASSERT_TRUE(status.ok());
+}
+
+TEST(DetectionsTransformationCalculatorTest, EmptyDetections) {
+  CalculatorRunner runner(ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"pb(
+    calculator: "DetectionTransformationCalculator"
+    input_stream: "DETECTIONS:input_detection"
+    input_stream: "IMAGE_SIZE:image_size"
+    output_stream: "PIXEL_DETECTIONS:output_detection"
+  )pb"));
+
+  std::pair<int, int> image_size({2000, 1000});
+  runner.MutableInputs()
+      ->Tag(kImageSizeTag)
+      .packets.push_back(
+          MakePacket<std::pair<int, int>>(image_size).At(Timestamp(0)));
+
+  auto status = runner.Run();
+  ASSERT_TRUE(status.ok());
+}
+
 TEST(DetectionsTransformationCalculatorTest,
      ConvertBoundingBoxToRelativeBoundingBox) {
   CalculatorRunner runner(ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"pb(