goodCropOpencv.py

img_path = outDirPath + 'images/' + imgName
img = cv2.imread(img_path, cv2.IMREAD_COLOR)

'''FIRST VERSION'''
mask = cv2.cvtColor(mask, cv2.COLOR_RGB2GRAY)
dest = cv2.bitwise_and(img, img, mask = mask)

for coordinates in coordinatesList:
        coords = coordinates[:len(coordinates)-1]
        #ANCIEN
        X = [pt[0] for pt in coords]
        Y = [pt[1] for pt in coords]
        Xmin=np.amin(X)
        Xmax=np.amax(X)
        Ymin=np.amin(Y)
        Ymax=np.amax(Y)
        crop_img = dest[int(Ymin):int(Ymax), int(Xmin):int(Xmax)]

'''SECOND VERSION (way better)'''
lengths=[dist(coords[i],coords[i+1]) for i in range(3)]
        maxLen = np.amax(lengths)
        width = maxLen
        height = maxLen / 1.41891891

        src = np.float32([
            [coords[0][0], coords[0][1]],
            [coords[1][0], coords[1][1]],
            [coords[3][0], coords[3][1]],
            [coords[2][0], coords[2][1]]
        ], dtype=float)

        dst = np.float32([
             [0., 0.],
             [width, 0.],
             [0., height],
             [width, height]
        ], dtype=float)

        M = cv2.getPerspectiveTransform(src, dst)
        new_crop_img = cv2.warpPerspective(img, M, (int(width), int(height)))


        '''
        plt.subplot(121), plt.imshow(crop_img), plt.title('Input')
        plt.subplot(122), plt.imshow(new_crop_img), plt.title('Output')
        plt.show()
        cv2.waitKey(0)
        '''