Rasperry Pi handwriting recognition

Question

I'm trying to make a handwriting recognition system using Raspberry Pi.My code detects the text but doesn't print it to screen.When I run the code,the img file detects the handwritings as they appear with blue borders.Another interesting thing is that it detects only in presence of source of light,I mean it's daytime and the environment isn't dark.When I don't turn on the light,the test1.jpg file is completely dark and handwritings aren't detected(I think this topic is about the camera I use or my environment isn't illuminated enough).

I'm doing something wrong but couldn't figure it out. I'm newby to programming.I hope that someone explains me these stuffs. Can you help me? Here is my code.

from picamera import PiCamera
import cv2
import pytesseract
from PIL import Image
from time import sleep
from picamera.array import PiRGBArray
import numpy as np

print ("Capturing Image")
camera = PiCamera()
camera.resolution = (640, 480)
camera.brightness = 50
camera.contrast = 70
camera.framerate = 30
rawCapture = PiRGBArray(camera, size=(640, 480))
camera.capture('/home/pi/Desktop/Photos/test1.jpg')

print("Captured")
sleep(1)
print("Wait, Processing")

img = cv2.imread('/home/pi/Desktop/Photos/test1.jpg', cv2.IMREAD_COLOR)
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 127, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]

items = cv2.findContours(thresh, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)
contours = items[0] if len(items) == 2 else items[1]

base = np.zeros(thresh.shape, dtype=np.uint8)
base = cv2.bitwise_not(base)

max_area = 0
for i in range(len(contours)):
    x, y, w, h = cv2.boundingRect(contours[i])
    ratio = h / w
    area = cv2.contourArea(contours[i])
    cv2.drawContours(img, [contours[i]], 0, (255, 0, 0), 2)

    if 1 < ratio < 3:
        max_area = max(area, max_area)
        #print("area: " + str(area) + ", max area: " + str(max_area) + ", ratio: " + str(ratio))
        # if 1000 < area < max_area / 2:
        if 1000 < area < 40000:
            mask = np.zeros(thresh.shape, dtype=np.uint8)
            cv2.drawContours(mask, [contours[i]], -1, color=255, thickness=-1)
            mean = cv2.mean(thresh, mask=mask)

            segment = np.zeros((h, w), dtype=np.uint8)
            segment[:h, :w] = thresh[y:y + h, x:x + w]

            if mean[0] > 150:
                # white, invert
                segment = cv2.bitwise_not(segment)

            base[y:y + h, x:x + w] = segment[:h, :w]
            cv2.imshow("base", base)

            cv2.drawContours(img, [contours[i]], 0, (255, 0, 0), 2)

            cv2.waitKey(0)

custom_config = r'-l eng --oem 3 --psm 6 -c tessedit_char_whitelist="ABCDEFGHIJKLMNOPQRSTUVWXYZ " '
text = pytesseract.image_to_string(base, config=custom_config)

print (text)

cv2.imshow("img", img)
cv2.imshow("base", base)

cv2.waitKey(0) 
cv2.destroyAllWindows()

I think there's something wrong with the pytesseract.image_to_string(base, config=custom_config) part.

By the way I'm using raspberry pi 4 2 gb,32 bit os and python 3.7.My camera is v1.3