Faster, Exception handling

README.md

@@ -21,48 +21,51 @@ $ gst-launch-1.0 nvarguscamerasrc sensor_id=0 ! nvoverlaysink
 # Example also shows sensor_mode parameter to nvarguscamerasrc
 # See table below for example video modes of example sensor
 $ gst-launch-1.0 nvarguscamerasrc sensor_id=0 ! \
-   'video/x-raw(memory:NVMM),width=3280, height=2464, framerate=21/1, format=NV12' ! \
-   nvvidconv flip-method=0 ! 'video/x-raw,width=960, height=720' ! \
+   'video/x-raw(memory:NVMM),width=1920, height=1080, framerate=30/1' ! \
+   nvvidconv flip-method=0 ! 'video/x-raw,width=960, height=540' ! \
    nvvidconv ! nvegltransform ! nveglglessink -e
 
 Note: The cameras appear to report differently than show below on some Jetsons. You can use the simple gst-launch example above to determine the camera modes that are reported by the sensor you are using. As an example the same camera from below may report differently on a Jetson Nano B01:
 
-GST_ARGUS: 3264 x 2464 FR = 21.000000 fps Duration = 47619048 ; Analog Gain range min 1.000000, max 10.625000; Exposure Range min 13000, max 683709000 
+GST_ARGUS: 1920 x 1080 FR = 29.999999 fps Duration = 33333334 ; Analog Gain range min 1.000000, max 10.625000; Exposure Range min 13000, max 683709000;
 
-You should adjust accordingly. As an example, for 3264x2464 @ 21 fps on sensor_id 1 of a Jetson Nano B01:
-$ gst-launch-1.0 nvarguscamerasrc sensor_id=1 ! \
-   'video/x-raw(memory:NVMM),width=3264, height=2464, framerate=21/1, format=NV12' ! \
-   nvvidconv flip-method=0 ! 'video/x-raw, width=816, height=616' ! \
-   nvvidconv ! nvegltransform ! nveglglessink -e
 
-Also, it's been noticed that the display transform is sensitive to width and height (in the above example, width=816, height=616). If you experience issues, check to see if your display width and height is the same ratio as the camera frame size selected (In the above example, 816x616 is 1/4 the size of 3264x2464).
+Also, it's been reported that the display transform is sensitive to width and height (in the above example, width=960, height=540). If you experience issues, check to see if your display width and height is the same ratio as the camera frame size selected (In the above example, 960x540 is 1/4 the size of 1920x1080).
 ```
 
 There are several examples:
 
-Note: You may need to install numpy for the Python examples to work, ie $ pip3 install numpy
 
+### simple_camera.py
 simple_camera.py is a Python script which reads from the camera and displays to a window on the screen using OpenCV:
-
+```
 $ python simple_camera.py
+```
+### face_detect.py
 
 face_detect.py is a python script which reads from the camera and uses  Haar Cascades to detect faces and eyes:
-
+```
 $ python face_detect.py
-
+```
 Haar Cascades is a machine learning based approach where a cascade function is trained from a lot of positive and negative images. The function is then used to detect objects in other images. 
 
 See: https://docs.opencv.org/3.3.1/d7/d8b/tutorial_py_face_detection.html 
 
+
 The third example is a simple C++ program which reads from the camera and displays to a window on the screen using OpenCV:
 
 ```
-$ g++ -std=c++11 -Wall -I/usr/lib/opencv simple_camera.cpp -L/usr/lib -lopencv_core -lopencv_highgui -lopencv_videoio -o simple_camera
+$ g++ -std=c++11 -Wall -I/usr/lib/opencv -I/usr/include/opencv4 simple_camera.cpp -L/usr/lib -lopencv_core -lopencv_highgui -lopencv_videoio -o simple_camera
 
 $ ./simple_camera
 ```
 
-The final example is dual_camera.py. This example is for the newer rev B01 of the Jetson Nano board, identifiable by two CSI-MIPI camera ports. This is a simple Python program which reads both CSI cameras and displays them in a window. The window is 960x1080. For performance, the script uses a separate thread for reading each camera image stream. To run the script:
+### dual_camera.py
+Note: You will need install numpy for the Dual Camera Python example to work, ie 
+```
+$ pip3 install numpy
+```
+The final example is dual_camera.py. This example is for the newer rev B01 of the Jetson Nano type boards (Jetson Nano, Jetson Xavier NX), identifiable by two CSI-MIPI camera ports. This is a simple Python program which reads both CSI cameras and displays them in a window. The window is 1080x540. For performance, the script uses a separate thread for reading each camera image stream. To run the script:
 
 ```
 $ python3 dual_camera.py

dual_camera.py

@@ -1,33 +1,24 @@
 # MIT License
-# Copyright (c) 2019,2020 JetsonHacks
-# See license
-# A very simple code snippet
+# Copyright (c) 2019-2022 JetsonHacks
+
+# A simple code snippet
 # Using two  CSI cameras (such as the Raspberry Pi Version 2) connected to a
-# NVIDIA Jetson Nano Developer Kit (Rev B01) using OpenCV
+# NVIDIA Jetson Nano Developer Kit with two CSI ports (Jetson Nano, Jetson Xavier NX) via OpenCV
 # Drivers for the camera and OpenCV are included in the base image in JetPack 4.3+
 
 # This script will open a window and place the camera stream from each camera in a window
 # arranged horizontally.
 # The camera streams are each read in their own thread, as when done sequentially there
 # is a noticeable lag
-# For better performance, the next step would be to experiment with having the window display
-# in a separate thread
 
 import cv2
 import threading
 import numpy as np
 
-# gstreamer_pipeline returns a GStreamer pipeline for capturing from the CSI camera
-# Flip the image by setting the flip_method (most common values: 0 and 2)
-# display_width and display_height determine the size of each camera pane in the window on the screen
-
-left_camera = None
-right_camera = None
-
 
 class CSI_Camera:
 
-    def __init__ (self) :
+    def __init__(self):
         # Initialize instance variables
         # OpenCV video capture element
         self.video_capture = None
@@ -39,54 +30,54 @@ def __init__ (self) :
         self.read_lock = threading.Lock()
         self.running = False
 
-
     def open(self, gstreamer_pipeline_string):
         try:
             self.video_capture = cv2.VideoCapture(
                 gstreamer_pipeline_string, cv2.CAP_GSTREAMER
             )
-
+            # Grab the first frame to start the video capturing
+            self.grabbed, self.frame = self.video_capture.read()
+
         except RuntimeError:
             self.video_capture = None
             print("Unable to open camera")
             print("Pipeline: " + gstreamer_pipeline_string)
-            return
-        # Grab the first frame to start the video capturing
-        self.grabbed, self.frame = self.video_capture.read()
+
 
     def start(self):
         if self.running:
             print('Video capturing is already running')
             return None
         # create a thread to read the camera image
         if self.video_capture != None:
-            self.running=True
+            self.running = True
             self.read_thread = threading.Thread(target=self.updateCamera)
             self.read_thread.start()
         return self
 
     def stop(self):
-        self.running=False
+        self.running = False
+        # Kill the thread
         self.read_thread.join()
+        self.read_thread = None
 
     def updateCamera(self):
         # This is the thread to read images from the camera
         while self.running:
             try:
                 grabbed, frame = self.video_capture.read()
                 with self.read_lock:
-                    self.grabbed=grabbed
-                    self.frame=frame
+                    self.grabbed = grabbed
+                    self.frame = frame
             except RuntimeError:
                 print("Could not read image from camera")
         # FIX ME - stop and cleanup thread
         # Something bad happened
-
 
     def read(self):
         with self.read_lock:
             frame = self.frame.copy()
-            grabbed=self.grabbed
+            grabbed = self.grabbed
         return grabbed, frame
 
     def release(self):
@@ -98,30 +89,32 @@ def release(self):
             self.read_thread.join()
 
 
-# Currently there are setting frame rate on CSI Camera on Nano through gstreamer
-# Here we directly select sensor_mode 3 (1280x720, 59.9999 fps)
+""" 
+gstreamer_pipeline returns a GStreamer pipeline for capturing from the CSI camera
+Flip the image by setting the flip_method (most common values: 0 and 2)
+display_width and display_height determine the size of each camera pane in the window on the screen
+Default 1920x1080
+"""
+
+
 def gstreamer_pipeline(
     sensor_id=0,
-    sensor_mode=3,
-    capture_width=1280,
-    capture_height=720,
-    display_width=1280,
-    display_height=720,
+    capture_width=1920,
+    capture_height=1080,
+    display_width=1920,
+    display_height=1080,
     framerate=30,
     flip_method=0,
 ):
     return (
-        "nvarguscamerasrc sensor-id=%d sensor-mode=%d ! "
-        "video/x-raw(memory:NVMM), "
-        "width=(int)%d, height=(int)%d, "
-        "format=(string)NV12, framerate=(fraction)%d/1 ! "
+        "nvarguscamerasrc sensor-id=%d ! "
+        "video/x-raw(memory:NVMM), width=(int)%d, height=(int)%d, framerate=(fraction)%d/1 ! "
         "nvvidconv flip-method=%d ! "
         "video/x-raw, width=(int)%d, height=(int)%d, format=(string)BGRx ! "
         "videoconvert ! "
         "video/x-raw, format=(string)BGR ! appsink"
         % (
             sensor_id,
-            sensor_mode,
             capture_width,
             capture_height,
             framerate,
@@ -132,15 +125,17 @@ def gstreamer_pipeline(
     )
 
 
-def start_cameras():
+def run_cameras():
+    window_title = "Dual CSI Cameras"
     left_camera = CSI_Camera()
     left_camera.open(
         gstreamer_pipeline(
             sensor_id=0,
-            sensor_mode=3,
+            capture_width=1920,
+            capture_height=1080,
             flip_method=0,
-            display_height=540,
             display_width=960,
+            display_height=540,
         )
     )
     left_camera.start()
@@ -149,45 +144,53 @@ def start_cameras():
     right_camera.open(
         gstreamer_pipeline(
             sensor_id=1,
-            sensor_mode=3,
+            capture_width=1920,
+            capture_height=1080,
             flip_method=0,
-            display_height=540,
             display_width=960,
+            display_height=540,
         )
     )
     right_camera.start()
 
-    cv2.namedWindow("CSI Cameras", cv2.WINDOW_AUTOSIZE)
-
-    if (
-        not left_camera.video_capture.isOpened()
-        or not right_camera.video_capture.isOpened()
-    ):
-        # Cameras did not open, or no camera attached
+    if left_camera.video_capture.isOpened() and right_camera.video_capture.isOpened():
 
-        print("Unable to open any cameras")
-        # TODO: Proper Cleanup
-        SystemExit(0)
+        cv2.namedWindow(window_title, cv2.WINDOW_AUTOSIZE)
 
-    while cv2.getWindowProperty("CSI Cameras", 0) >= 0 :
-
-        _ , left_image=left_camera.read()
-        _ , right_image=right_camera.read()
-        camera_images = np.hstack((left_image, right_image))
-        cv2.imshow("CSI Cameras", camera_images)
-
-        # This also acts as
-        keyCode = cv2.waitKey(30) & 0xFF
-        # Stop the program on the ESC key
-        if keyCode == 27:
-            break
+        try:
+            while True:
+                _, left_image = left_camera.read()
+                _, right_image = right_camera.read()
+                # Use numpy to place images next to each other
+                camera_images = np.hstack((left_image, right_image)) 
+                # Check to see if the user closed the window
+                # Under GTK+ (Jetson Default), WND_PROP_VISIBLE does not work correctly. Under Qt it does
+                # GTK - Substitute WND_PROP_AUTOSIZE to detect if window has been closed by user
+                if cv2.getWindowProperty(window_title, cv2.WND_PROP_AUTOSIZE) >= 0:
+                    cv2.imshow(window_title, camera_images)
+                else:
+                    break
+
+                # This also acts as
+                keyCode = cv2.waitKey(30) & 0xFF
+                # Stop the program on the ESC key
+                if keyCode == 27:
+                    break
+        finally:
+
+            left_camera.stop()
+            left_camera.release()
+            right_camera.stop()
+            right_camera.release()
+        cv2.destroyAllWindows()
+    else:
+        print("Error: Unable to open both cameras")
+        left_camera.stop()
+        left_camera.release()
+        right_camera.stop()
+        right_camera.release()
 
-    left_camera.stop()
-    left_camera.release()
-    right_camera.stop()
-    right_camera.release()
-    cv2.destroyAllWindows()
 
 
 if __name__ == "__main__":
-    start_cameras()
+    run_cameras()