How to crop image by main canny edge

I got the following image:

And trying to crop image by code:

def getoriginpaper(image):

    image2 = image.copy()
    w, h = image.shape[::-1]

    # image = cv2.blur(image, (3, 3), 0)
    image = cv2.medianBlur(image, 9)  # 9
    
    img = cv2.GaussianBlur(image, (9, 9), 0)

    canny = cv2.Canny(img, 30, 100)  # 50 150

    x, y, w, h = cv2.boundingRect(canny)
    cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)
    cv2.imshow('boundingrect_canny', img)
    cv2.waitKey(0)
    return image2[y:y+h, x:x+w]

canny image like this:

Problem is, see image below:

So, above is what I got by boundingRect, but acctually, I wanna left side go likes the green line, and I know reason is the corner marked with red circle.

Any way to remove the red circle part to make it left side as the green line?

Any suggestions are great appreciated.

Thanks.