crop image using OpenCV

Try this way:

import sys
from PyQt5.QtWidgets import QMainWindow, QApplication, QLabel
from PyQt5.QtGui     import QPixmap, QImage, qRgb
from PyQt5.QtCore    import Qt

import numpy as np
import cv2

app = QApplication(sys.argv) 

gray_color_table = [qRgb(i, i, i) for i in range(256)]

def NumpyToQImage(im):
    qim = QImage()
    if im is None:
        return qim
    if im.dtype == np.uint8:
        if len(im.shape) == 2:
            qim = QImage(im.data, im.shape[1], im.shape[0], im.strides[0], QImage.Format_Indexed8)
            qim.setColorTable(gray_color_table)
        elif len(im.shape) == 3:
            if im.shape[2] == 3:
                qim = QImage(im.data, im.shape[1], im.shape[0], im.strides[0], QImage.Format_RGB888)
            elif im.shape[2] == 4:
                qim = QImage(im.data, im.shape[1], im.shape[0], im.strides[0], QImage.Format_ARGB32)
    return qim

img = cv2.imread('D:/_Qt/img/pyqt.jpg')
qimg = NumpyToQImage(img)
assert(not qimg.isNull())

label = QLabel()
pixmap = QPixmap(qimg)
pixmap.scaled(200, 200) 
label.setPixmap(pixmap)
label.show()

label_1 = QLabel()
pixmap  = QPixmap('D:/_Qt/img/pyqt.jpg')
label_1.setPixmap(pixmap)
label_1.setScaledContents(True)
label_1.show()

img = cv2.imread('D:/_Qt/img/pyqt.jpg')
img = np.copy(img[0:90, 140:224, :]) 
qimg2 = NumpyToQImage(img)
assert(not qimg2.isNull())

label_2 = QLabel()
label_2.resize(224, 224)
pixmap = QPixmap(qimg2)
pixmap.scaled(300, 300, Qt.IgnoreAspectRatio, Qt.FastTransformation)
label_2.setPixmap(pixmap)
label_2.setScaledContents(True)
label_2.show()

app.exec_()

Or so:

import cv2
import numpy as np             

resim = cv2.imread("img1.jpg")    

cv2.imshow("img1.jpg", resim) 

Area = resim[100:300, 100:320]
cv2.imshow("Area -> img1.jpg", Area)

cv2.waitKey(0)
cv2.destroyAllWindows()

Or so:

import cv2
import numpy as np

image = cv2.imread('im.png', -1)
mask = np.zeros(image.shape, dtype=np.uint8)
roi_corners = np.array([[(200,10),  (400,10), 
                         (400,100), (600,100), 
                         (600,200), (400,200), 
                         (400,300), (200,300),
                         (200,200), (10,200),
                         (10,100),  (200,100),
                       ]], 
                       dtype=np.int32)

channel_count = image.shape[2]  
ignore_mask_color = (255,)*channel_count
cv2.fillPoly(mask, roi_corners, ignore_mask_color)

masked_image = cv2.bitwise_and(image, mask)

cv2.imwrite('image_masked.png', masked_image)

cv2.imshow("image_masked.png", masked_image)
cv2.imshow("img1.jpg", image)

cv2.waitKey(0)
cv2.destroyAllWindows()

import cv2
import numpy as np

image = cv2.imread('im.png', -1)
mask = np.zeros(image.shape, dtype=np.uint8)
roi_corners = np.array([[(200,10),  (400,10), 
                         (400,100), (600,100), 
                         (600,200), (400,200), 
                         (400,300), (200,300),
                         (200,200), (10,200),
                         (10,100),  (200,100),
                       ]], 
                       dtype=np.int32)

channel_count = image.shape[2]  
ignore_mask_color = (255,)*channel_count             
cv2.fillPoly(mask, roi_corners, ignore_mask_color)
masked_image = cv2.bitwise_and(image, mask)
cv2.imwrite('image_masked.png', masked_image)

cv2.imshow("img1.jpg", image)
cv2.imshow("image_masked.png", masked_image)

### vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

image = cv2.imread("image_masked.png")
r     = 200.0 / image.shape[1]                                  
dim   = (200, int(image.shape[0] * r))                          
resized = cv2.resize(image, dim, interpolation=cv2.INTER_AREA)

lower_white = np.array([0, 0, 0], dtype=np.uint8)
upper_white = np.array([0, 0, 0], dtype=np.uint8)

mask = cv2.inRange(resized, lower_white, upper_white) 
res  = cv2.bitwise_not(resized, resized, mask)
cv2.imshow('res', res) 

### ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


cv2.waitKey(0)
cv2.destroyAllWindows()