Detect red rectangle in image and crop it

Question

I am having the following image and would like to detect the red rectangle to cut it away:

On the right side is the wanted result.

I tried the following:

!curl -o messi_card_hor.jpg https://d1w8cc2yygc27j.cloudfront.net/-2675427100542262593/7010047673982964277.jpg
!curl -o ronaldo_card.jpg https://d1w8cc2yygc27j.cloudfront.net/-6081046349913684185/-7772716368837553466.jpg
!curl -o ronaldo_sticker.jpg https://d1w8cc2yygc27j.cloudfront.net/6559100964212657924/2938835010875297356.jpg
!curl -o mini.jpg https://d1w8cc2yygc27j.cloudfront.net/-2342182173466831883/-5809028710077412417.jpg
!curl -o maradonna.jpg https://d1w8cc2yygc27j.cloudfront.net/-7109542822702569515/-8340360203776679658.jpg
!curl -o mess.jpg https://d1w8cc2yygc27j.cloudfront.net/-8505602657852037324/-5181528839070911125.jpg
!curl -o thierry.jpg https://d1w8cc2yygc27j.cloudfront.net/-5353994491295474458/6765375063661749632.jpg



# import cv
import cv2
import numpy as np
import sys
from google.colab.patches import cv2_imshow
import ipdb
%pdb on


def get_new(old):
    new = np.ones(old.shape, np.uint8)
    cv2.bitwise_not(new,new)
    return new

#START
def detectRedBorder(img):
    orig = cv2.imread(img)
    baseImg = orig

    result = orig.copy()
    orig = cv2.cvtColor(orig, cv2.COLOR_BGR2HSV)
    lower = np.array([155,25,0])
    upper = np.array([179,255,255])
    mask = cv2.inRange(orig, lower, upper)
    result = cv2.bitwise_and(result, result, mask=mask)

    print("baseImg:")
    # cv2.imshow('mask', mask)
    cv2_imshow(baseImg)
    print("mask:")
    # cv2.imshow('mask', mask)
    cv2_imshow(mask)
    print("result:")
    # cv2.imshow('result', result)
    cv2_imshow(result)
    # cv2.waitKey()


    cv2.destroyAllWindows()


# run script
detectRedBorder("./messi_card_hor.jpg")
detectRedBorder("./ronaldo_card.jpg")
detectRedBorder("./ronaldo_sticker.jpg")
detectRedBorder("./mini.jpg") 
detectRedBorder("./maradonna.jpg") 
detectRedBorder("./mess.jpg") 
detectRedBorder("./thierry.jpg") 

Find here the google colab with the executable code.

I am successfully creating the mask, BUT still I am struggeling how to identify the rectangle and crop it away.

I really appeciate your replies!