def prep_im_for_blob(im, pixel_means, target_size, max_size):
    """Mean subtract and scale an image for use in a blob."""

    im = im.astype(np.float32, copy=False)
    im -= pixel_means
    # im = im[:, :, ::-1]
    im_shape = im.shape
    im_size_min = np.min(im_shape[0:2])
    im_size_max = np.max(im_shape[0:2])
    im_scale = float(target_size) / float(im_size_min)
    # Prevent the biggest axis from being more than MAX_SIZE
    # if np.round(im_scale * im_size_max) > max_size:
    #     im_scale = float(max_size) / float(im_size_max)
    # im = imresize(im, im_scale)
    im = cv2.resize(im, None, None, fx=im_scale, fy=im_scale,
                    interpolation=cv2.INTER_LINEAR)

    return im, im_scale
Mean subtract and scale an image for use in a blob.
lib/model/utils/blob.py