Overload resolution failed: - array is not a numerical tuple - Expected Ptr<cv::UMat> for argu-CodePudding

Im trying to develope a captcha solver, but I do not know how openCV works properly. Heres is my code, and the message error is below.

import os
import cv2
import numpy as np

archives = glob.glob('captcha_tratado/*')
for archive in archives:
    image = cv2.imread(archive)
    image = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)
    _, image = cv2.threshold(image, 0, 255, cv2.THRESH_BINARY_INV)

    # find contour of each letter
    contours = cv2.findContours(
        image, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

    letter_regions = []

    for contour in contours:
        (x, y, width, height) = cv2.boundingRect(contour)
        area = cv2.countourArea(contour)
        if area > 115:
            letter_regions.append((x, y, width, height))
    if len(letter_regions) <= 2:
        pass

    # find contour and separate in individual files
    image_final = cv2.merge([image] * 3)
    i = 0
    for rectangle in letter_regions:
        x, y, width, height = rectangle
        image_letter = image[y-2:y height 2, x-2:x width 2]
        i  = 1
        fileName = os.path.basename(archive).replace(".png", f"letter{i}.png")
        cv2.imwrite(f'letras/{fileName}', image_letter)
        cv2.rectangle(image_final, (x-2, y-2),
                      (x width 2, y height 2), (0, 255, 0), 1)
    fileName = os.path.basename(archive)
    cv2.imwrite(f'identificado/{fileName}', image_final)```




ERROR MESSAGE:

(x, y, width, height) = cv2.boundingRect(contour)

cv2.error: OpenCV(4.6.0) :-1: error: (-5:Bad argument) in function 'boundingRect'

Overload resolution failed:

array is not a numerical tuple

Expected Ptr<cv::UMat> for argument 'array'

CodePudding user response：

cv2.findCountours returns two things: The contour list retrieved according to the contour approximation method and a list of contour hierarchy. Expect two return values even if you don't use one, change the call to the function to this:

contours, _ = cv2.findContours(image, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

For further reference, here's the function documentation.