How to name each tile in CV2 imshow?

Question

cv2.namedWindow('All cameras', cv2.WINDOW_AUTOSIZE)

top_row = np.concatenate(
    (sensor_data1['rgb_image'], sensor_data4['rgb_image']), axis=1)
lower_row = np.concatenate(
    (sensor_data2['rgb_image'], sensor_data3['rgb_image']), axis=1)
tiled = np.concatenate(
    (top_row, lower_row), axis=0)

cv2.imshow('All cameras', tiled)
cv2.waitKey(1)

My imshow window has now 4 video Streaming from 4 sensors. How can I name each tile with different names?

For eg: Left top as Sensor 1, right top as Sensor 2 inside the imshow?

Answer 1

I do not exactly know, if you can label the tiles directly, because you fabricate somehow a "merged" image matrix with concatenate, so you have to add every border, frame etc. yourself. You might just use cv.putText and calculate the position of the label inside your image:

# importing cv2
import cv2
 
# font
font = cv2.FONT_HERSHEY_SIMPLEX
  
# position of the label
pos = (50, 50)
  
# fontScale
fontScale = 1
   
# Blue color in BGR
color = (255, 0, 0)
  
# Line thickness of 2 px
thickness = 2
   
# Using cv2.putText() method
image = cv2.putText(image, 'MySensorDataNumber1', pos, font, 
                   fontScale, color, thickness, cv2.LINE_AA)

Be aware the 0,0 position is always the bottom left corner of the image, but you can also specify an other one as optional parameter 'bottomLeftOrigin'.