No error, no video output using CSI camera

[diniramadhani553]

I’m trying to make a facial emotion classification program through a video stream. I’m using Jetson Nano 2GB and swap memory and csi camera raspberry pi v2, and python 3 in my virtualenv. I have installed opencv 4.1 which supports gstreamer. I’ve tried the csi camera code from github and it worked to open the camera. I don’t think there is an error, but the video stream doesn’t come out and the program stops. here is my code :

import numpy as np
import cv2
from keras.preprocessing import image

#-----------------------------
#opencv initialization
def gstreamer_pipeline(
    capture_width=1280,
    capture_height=720,
    display_width=1280,
    display_height=720,
    framerate=60,
    flip_method=0,
):
    return (
        "nvarguscamerasrc ! "
        "video/x-raw(memory:NVMM), "
        "width=(int)%d, height=(int)%d, "
        "format=(string)NV12, 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"
        % (
            capture_width,
            capture_height,
            framerate,
            flip_method,
            display_width,
            display_height,
        )
    )

face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
# To flip the image, modify the flip_method parameter (0 and 2 are the most common)
cap = cv2.VideoCapture(gstreamer_pipeline(flip_method=0), cv2.CAP_GSTREAMER)

#face expression recognizer initialization
from keras.models import model_from_json
model = model_from_json(open("facial_expression_model_structure.json", "r").read())
model.load_weights('facial_expression_model_weights.h5') #load weights

#-----------------------------
emotions = ('angry', 'disgust', 'fear', 'happy', 'sad', 'surprise', 'neutral')

def show_camera():
	if cap.isOpened():
		window_handle = cv2.namedWindow("CSI Camera", cv2.WINDOW_AUTOSIZE)
		# Window
		while cv2.getWindowProperty("CSI Camera", 0) >= 0:
			ret_val, img = cap.read()
			gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
			faces = face_cascade.detectMultiScale(gray, 1.3, 5)
			#print(faces) #locations of detected faces
			for (x,y,w,h) in faces:
				cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2) #draw rectangle to main image
	
				detected_face = img[int(y):int(y+h), int(x):int(x+w)] #crop detected face
				detected_face = cv2.cvtColor(detected_face, cv2.COLOR_BGR2GRAY) #transform to gray scale
				detected_face = cv2.resize(detected_face, (48, 48)) #resize to 48x48
		
				img_pixels = image.img_to_array(detected_face)
				img_pixels = np.expand_dims(img_pixels, axis = 0)
	
				img_pixels /= 255 #pixels are in scale of [0, 255]. normalize all pixels in scale of [0, 1]
		
				predictions = model.predict(img_pixels) #store probabilities of 7 expressions
		
				#find max indexed array 0: angry, 1:disgust, 2:fear, 3:happy, 4:sad, 5:surprise, 6:neutral
				max_index = np.argmax(predictions[0])
		
				emotion = emotions[max_index]
		
				#write emotion text above rectangle
				cv2.putText(img, emotion, (int(x), int(y)), cv2.FONT_HERSHEY_SIMPLEX, 1, (255,255,255), 2)
		
				#process on detected face end
				
			cv2.imshow("CSI Camera", img)
			# This also acts as
			keyCode = cv2.waitKey(30) & 0xFF
			# Stop the program on the ESC key
			if keyCode == 27:
				break
      
		cap.release()
		cv2.destroyAllWindows()
	else:
		print("Unable to open camera")

and this is the output

please anyone help me?

[DaneLLL]

Hi,
We have tried this sample with Jetson Nano + Pi camera v2:
OpenCV Video Capture with GStreamer doesn't work on ROS-melodic - #3 by DaneLLL

Please give it a try.