AffineInvariantFeatures.py 文件源码

def affine_skew(self, tilt, phi, img, mask=None):
        h, w = img.shape[:2]
        if mask is None:
            mask = np.zeros((h, w), np.uint8)
            mask[:] = 255
        A = np.float32([[1, 0, 0], [0, 1, 0]])
        if phi != 0.0:
            phi = np.deg2rad(phi)
            s, c = np.sin(phi), np.cos(phi)
            A = np.float32([[c, -s], [s, c]])
            corners = [[0, 0], [w, 0], [w, h], [0, h]]
            tcorners = np.int32(np.dot(corners, A.T))
            x, y, w, h = cv2.boundingRect(tcorners.reshape(1, -1, 2))
            A = np.hstack([A, [[-x], [-y]]])
            img = cv2.warpAffine(img, A, (w, h), flags=cv2.INTER_LINEAR, borderMode=cv2.BORDER_REPLICATE)
        if tilt != 1.0:
            s = 0.8*np.sqrt(tilt * tilt - 1)
            img = cv2.GaussianBlur(img, (0, 0), sigmaX=s, sigmaY=0.01)
            img = cv2.resize(img, (0, 0), fx=1.0 / tilt, fy=1.0, interpolation=cv2.INTER_NEAREST)
            A[0] /= tilt
        if phi != 0.0 or tilt != 1.0:
            h, w = img.shape[:2]
            mask = cv2.warpAffine(mask, A, (w, h), flags=cv2.INTER_NEAREST)
        Ai = cv2.invertAffineTransform(A)
        return img, mask, Ai