How to get the face temperature in opencv python

Question

I'm new to the forum and I certainly don't know the rules. But I have a question I want to determine the temperature of the face with a Raspberry 4 and two cameras one normal, the other thermal (MLX90640). My question is how can I determine the temperature of the face with the thermal camera every time the normal camera detects a face? I wrote a code but it detects the temperature of the environment not that of the face. I tried a correction but I have an error message that I would post. Thank you

import cv2,io,imutils
import numpy as np
from imutils.video import VideoStream
import time
import board
import busio
import adafruit_mlx90640
import random
import math



PRINT_TEMPERATURES = True
i2c = busio.I2C(board.SCL, board.SDA, frequency=800000)
mlx = adafruit_mlx90640.MLX90640(i2c)
print("MLX addr detected on I2C")
print([hex(i) for i in mlx.serial_number])
frame = [0]*768
mlx.refresh_rate = adafruit_mlx90640.RefreshRate.REFRESH_8_HZ
print("Starting Camera...........")
detector= cv2.CascadeClassifier('/home/pi/opencv/data/haarcascades/haarcascade_frontalface_alt.xml')
cap = cv2.VideoCapture(0)
max_t=0
height = cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 24)
width = cap.set(cv2.CAP_PROP_FRAME_WIDTH, 32)
fps = cap.set(cv2.CAP_PROP_FPS, 10)
height = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
width = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
while(True):
    ret,img = cap.read()
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    faces = detector.detectMultiScale(gray, 1.3, 5)
    mlx.getFrame(frame)
    for h in range(24):
        for w in range(32):

            for (x,y,w,h) in faces:
                cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
                roi = frame [y:y+h,x:x+w]
                max_t = max(roi)
                min_t = int (min(frame))
                roi_gray = roi.astype(np.uint8)
                roi = cv2.applyColorMap(roi, cv2.COLORMAP_JET)
                text = "Min : "+ str(min_t) + "C Max :" + str(max_t) + "C"
                org = (10, 40)
                font = cv2.FONT_HERSHEY_SIMPLEX
                cv2.putText(roi, text, org, font, 1, (255, 255, 255), 2, cv2.LINE_AA)
                cv2.imshow('Screen1',roi)




        if PRINT_TEMPERATURES:
            print("%d",max_t)

    text = "occupe"

    cv2.imshow('Screen',img)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

    Traceback (most recent call last):
  File "/home/pi/Downloads/ta.py", line 39, in <module>
    roi = frame [y:y+h,x:x+w]
TypeError: list indices must be integers or slices, not tuple

You define your frame as a 1-dimensional array ```frame = [0]*768``` but you here you are accessing rows and columns ```frame [y:y+h,x:x+w]``` which returns the error as your defined frame is 1-dimensional. From a quick glance at the documentation to read the pixel (w,h) you have to write the following expression ```t = frame[h * 32 + w]``` but only if frame is 768 elements long. The link to the reference: [mlx examples](https://circuitpython.readthedocs.io/projects/mlx90640/en/latest/examples.html) — sebko_iic, Jun 06 '20 at 20:40
yes, normally but when I put the formula "t = h * 32 + w" in the for (x,y,w,h) in faces : I have another error that list of index out of range — user13687982, Jun 06 '20 at 23:31

How to get the face temperature in opencv python

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