🔲 Pad and frame

---

pad_frame

def pad_frame(
    t:ndarray, # torch.Tensor,  # 3D+ image tensor, [...,H,W,C]
    frame_px:int=1, # Number of pixels to pad each side.
    val:float=0, # Value to pad with.
):

Pad H and W dimensitons of an image tensor with val of thickness frame_px

Examples

pad_frame(np.zeros((3,3,1)), frame_px=2, val=1).transpose(-1,0,1).astype(int)

array([[[1, 1, 1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1, 1, 1],
        [1, 1, 0, 0, 0, 1, 1],
        [1, 1, 0, 0, 0, 1, 1],
        [1, 1, 0, 0, 0, 1, 1],
        [1, 1, 1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1, 1, 1]]])

# 1px black frame inside 2px white frame (gutter).
pad_frame(pad_frame(np.ones((3,3,1))), frame_px=2, val=1 ).transpose(-1,0,1).astype(int)

array([[[1, 1, 1, 1, 1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1, 1, 1, 1, 1],
        [1, 1, 0, 0, 0, 0, 0, 1, 1],
        [1, 1, 0, 1, 1, 1, 0, 1, 1],
        [1, 1, 0, 1, 1, 1, 0, 1, 1],
        [1, 1, 0, 1, 1, 1, 0, 1, 1],
        [1, 1, 0, 0, 0, 0, 0, 1, 1],
        [1, 1, 1, 1, 1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1, 1, 1, 1, 1]]])

---

pad_frame_gutters

def pad_frame_gutters(
    t:ndarray, # 3D+ Tensor image tensor, [...,H,W,C]
    gutter_px:int=3, # Write gutter in pixels.
    frame_px:int=1, # Black frame, in pixels
):

Add a black frame and white gutters around an image

Examples

Lo(image)

array[3, 196, 196] n=115248 (0.9Mb) x∈[-4.053e-09, 1.000] μ=0.361 σ=0.248

Lo(pad_frame_gutters(image.transpose(1, 2, 0), gutter_px=15, frame_px=3))

array[232, 232, 3] n=161472 (1.2Mb) x∈[-4.053e-09, 1.000] μ=0.500 σ=0.359

def to_pil(x):
    return Image.fromarray(np.uint8(x*255))

to_pil(pad_frame_gutters(image.transpose(1, 2, 0), gutter_px=15, frame_px=3))