simplePerspectiveTransform.py 文件源码

def simplePerspectiveTransform(img, quad, shape=None,
                               interpolation=cv2.INTER_LINEAR,
                               inverse=False):
    p = sortCorners(quad).astype(np.float32)
    if shape is not None:
        height, width = shape
    else:
        # get output image size from avg. quad edge length
        width = int(round(0.5 * (np.linalg.norm(p[0] - p[1]) +
                                 np.linalg.norm(p[3] - p[2]))))
        height = int(round(0.5 * (np.linalg.norm(p[1] - p[2]) +
                                  np.linalg.norm(p[0] - p[3]))))

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

    if inverse:
        s0, s1 = img.shape[:2]
        dst /= ((width / s1), (height / s0))
        H = cv2.getPerspectiveTransform(dst, p)
    else:
        H = cv2.getPerspectiveTransform(p, dst)

    return cv2.warpPerspective(img, H, (width, height), flags=interpolation)