1import cv2
 2import numpy as np
 3
 4def main(inputs, outputs, parameters, synchronise):
 5    '''
 6    ## Detects Edges in an Image\n
 7    It takes in two parameters `Lower` and `Upper`. These parameters are used as the limits in Canny Edge 
 8    Detection. First we convert the input `BGR` image to `GRAY`. Next we apply Canny Edge Detection via the 
 9    `cv2.Canny()` function. The resulting image is then converted back to `BGR`.
10
11    This image is then shared to the wire via the `share_image()` function.
12    
13    **Inputs**: BGR Image
14
15    **Outputs**: BGR Image
16
17    **Parameters**: Lower, Upper (Threshold values)
18    '''
19    lower = int(parameters.read_string("Lower"))
20    upper = int(parameters.read_string("Upper"))
21
22    auto_enable = False
23    try:
24        enable = inputs.read_number("Enable")
25    except Exception:
26        auto_enable = True
27
28    while(auto_enable or inputs.read_number('Enable')):
29        frame = inputs.read_image("Img")
30        if frame is None:
31            continue
32
33        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
34        edge_img = cv2.Canny(frame, lower, upper)
35        edge_img = cv2.cvtColor(edge_img, cv2.COLOR_GRAY2BGR)
36        
37        outputs.share_image('Out', edge_img)
38
39        synchronise()