From 13fe7682106922fef9b7af63dd9a0bed4aef5bde Mon Sep 17 00:00:00 2001
From: Miguel Xochicale <m.xochicale@ucl.ac.uk>
Date: Tue, 20 Feb 2024 22:22:01 +0000
Subject: [PATCH] adds example live_camera_edge_detection #30

---
 .../live_camera_edge_detection/README.md      | 19 +++++
 .../live_camera_edge_detection/main.py        | 73 +++++++++++++++++++
 .../requirements.txt                          |  2 +
 3 files changed, 94 insertions(+)
 create mode 100644 rerun/examples/live_camera_edge_detection/README.md
 create mode 100644 rerun/examples/live_camera_edge_detection/main.py
 create mode 100644 rerun/examples/live_camera_edge_detection/requirements.txt

diff --git a/rerun/examples/live_camera_edge_detection/README.md b/rerun/examples/live_camera_edge_detection/README.md
new file mode 100644
index 0000000..5359aa7
--- /dev/null
+++ b/rerun/examples/live_camera_edge_detection/README.md
@@ -0,0 +1,19 @@
+# live_camera_edge_detection
+
+## Download scripts
+```
+wget https://raw.githubusercontent.com/rerun-io/rerun/main/examples/python/live_camera_edge_detection/requirements.txt
+wget https://raw.githubusercontent.com/rerun-io/rerun/main/examples/python/live_camera_edge_detection/main.py
+
+```
+
+
+## Run scripts
+mamba activate rrVE
+pip install -r requirements.txt
+python main.py
+
+
+## Reference
+https://github.com/rerun-io/rerun/tree/main/examples/python/live_camera_edge_detection
+
diff --git a/rerun/examples/live_camera_edge_detection/main.py b/rerun/examples/live_camera_edge_detection/main.py
new file mode 100644
index 0000000..33bab09
--- /dev/null
+++ b/rerun/examples/live_camera_edge_detection/main.py
@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+"""
+Very simple example of capturing from a live camera.
+
+Runs the opencv canny edge detector on the image stream.
+"""
+from __future__ import annotations
+
+import argparse
+
+import cv2
+import rerun as rr  # pip install rerun-sdk
+
+
+def run_canny(num_frames: int | None) -> None:
+    # Create a new video capture
+    cap = cv2.VideoCapture(0)
+
+    frame_nr = 0
+
+    while cap.isOpened():
+        if num_frames and frame_nr >= num_frames:
+            break
+
+        # Read the frame
+        ret, img = cap.read()
+        if not ret:
+            if frame_nr == 0:
+                print("Failed to capture any frame. No camera connected?")
+            else:
+                print("Can't receive frame (stream end?). Exiting…")
+            break
+
+        # Get the current frame time. On some platforms it always returns zero.
+        frame_time_ms = cap.get(cv2.CAP_PROP_POS_MSEC)
+        if frame_time_ms != 0:
+            rr.set_time_nanos("frame_time", int(frame_time_ms * 1_000_000))
+
+        rr.set_time_sequence("frame_nr", frame_nr)
+        frame_nr += 1
+
+        # Log the original image
+        rgb = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
+        rr.log("image/rgb", rr.Image(rgb))
+
+        # Convert to grayscale
+        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
+        rr.log("image/gray", rr.Image(gray))
+
+        # Run the canny edge detector
+        canny = cv2.Canny(gray, 50, 200)
+        rr.log("image/canny", rr.Image(canny))
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Streams a local system camera and runs the canny edge detector.")
+    parser.add_argument(
+        "--device", type=int, default=0, help="Which camera device to use. (Passed to `cv2.VideoCapture()`)"
+    )
+    parser.add_argument("--num-frames", type=int, default=None, help="The number of frames to log")
+
+    rr.script_add_args(parser)
+    args = parser.parse_args()
+
+    rr.script_setup(args, "rerun_example_live_camera_edge_detection")
+
+    run_canny(args.num_frames)
+
+    rr.script_teardown(args)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/rerun/examples/live_camera_edge_detection/requirements.txt b/rerun/examples/live_camera_edge_detection/requirements.txt
new file mode 100644
index 0000000..51d3a8c
--- /dev/null
+++ b/rerun/examples/live_camera_edge_detection/requirements.txt
@@ -0,0 +1,2 @@
+opencv-python
+rerun-sdk