CenterCropPad¶

CenterCropPad - 18¶

Version¶

name: CenterCropPad (GitHub)
domain: main
since_version: 18
function: True
support_level: SupportType.COMMON
shape inference: True

This version of the operator has been available since version 18.

Summary¶

Center crop or pad an input to given dimensions.

The crop/pad dimensions can be specified for a subset of the axes; unspecified dimensions will remain unchanged.

If the input dimensions are larger than the target crop dimensions, a centered cropping window will be extracted from the input. The starting value for the cropping window is rounded down, which means that if the difference between the input shape and the crop shape is odd, the cropping window will be shifted half a pixel to the left of the input center.

If the input dimensions are smaller than the target crop dimensions, the input will be padded equally on both sides to center it in the output. In cases where the total number of padding pixels is odd, an additional pixel will be added to the right side.

The padding value used is zero.

Attributes¶

axes - INTS :

If provided, it specifies a subset of axes that ‘shape’ refer to. If not provided, all axes are assumed [0, 1, …, r-1], where r = rank(data). Negative value means counting dimensions from the back. Accepted range is [-r, r-1], where r = rank(data). Behavior is undefined if an axis is repeated.

Inputs¶

input_data (heterogeneous) - T:

Input to extract the centered crop from.
shape (heterogeneous) - Tind:

1-D tensor representing the cropping window dimensions.

Outputs¶

output_data (heterogeneous) - T:

Output data.

Type Constraints¶

T in ( tensor(bfloat16), tensor(bool), tensor(complex128), tensor(complex64), tensor(double), tensor(float), tensor(float16), tensor(int16), tensor(int32), tensor(int64), tensor(int8), tensor(string), tensor(uint16), tensor(uint32), tensor(uint64), tensor(uint8) ):

Constrain input and output types to all tensor types.
Tind in ( tensor(int32), tensor(int64) ):

Constrain indices to integer types

Examples¶

_center_crop_pad_crop¶

import numpy as np
import onnx

node = onnx.helper.make_node(
    "CenterCropPad",
    inputs=["x", "shape"],
    outputs=["y"],
)

# First dim is even diff, second is uneven
x = np.random.randn(20, 10, 3).astype(np.float32)
shape = np.array([10, 7, 3], dtype=np.int64)
y = x[5:15, 1:8, :]

expect(node, inputs=[x, shape], outputs=[y], name="test_center_crop_pad_crop")

_center_crop_pad_pad¶

import numpy as np
import onnx

node = onnx.helper.make_node(
    "CenterCropPad",
    inputs=["x", "shape"],
    outputs=["y"],
)

# First dim is even diff, second is uneven
x = np.random.randn(10, 7, 3).astype(np.float32)
shape = np.array([20, 10, 3], dtype=np.int64)
y = np.zeros([20, 10, 3], dtype=np.float32)
y[5:15, 1:8, :] = x

expect(node, inputs=[x, shape], outputs=[y], name="test_center_crop_pad_pad")

_center_crop_pad_crop_and_pad¶

import numpy as np
import onnx

node = onnx.helper.make_node(
    "CenterCropPad",
    inputs=["x", "shape"],
    outputs=["y"],
)

# Cropping on first dim, padding on second, third stays the same
x = np.random.randn(20, 8, 3).astype(np.float32)
shape = np.array([10, 10, 3], dtype=np.int64)
y = np.zeros([10, 10, 3], dtype=np.float32)
y[:, 1:9, :] = x[5:15, :, :]

expect(
    node,
    inputs=[x, shape],
    outputs=[y],
    name="test_center_crop_pad_crop_and_pad",
)

_center_crop_pad_crop_axes_hwc¶

import numpy as np
import onnx

node = onnx.helper.make_node(
    "CenterCropPad",
    inputs=["x", "shape"],
    outputs=["y"],
    axes=[0, 1],
)

# Cropping on first dim, padding on second, third stays the same
x = np.random.randn(20, 8, 3).astype(np.float32)
shape = np.array([10, 9], dtype=np.int64)
y = np.zeros([10, 9, 3], dtype=np.float32)
y[:, :8, :] = x[5:15, :, :]

expect(
    node,
    inputs=[x, shape],
    outputs=[y],
    name="test_center_crop_pad_crop_axes_hwc",
)

_center_crop_pad_crop_negative_axes_hwc¶

import numpy as np
import onnx

node = onnx.helper.make_node(
    "CenterCropPad",
    inputs=["x", "shape"],
    outputs=["y"],
    axes=[-3, -2],
)

# Cropping on first dim, padding on second, third stays the same
x = np.random.randn(20, 8, 3).astype(np.float32)
shape = np.array([10, 9], dtype=np.int64)
y = np.zeros([10, 9, 3], dtype=np.float32)
y[:, :8, :] = x[5:15, :, :]

expect(
    node,
    inputs=[x, shape],
    outputs=[y],
    name="test_center_crop_pad_crop_negative_axes_hwc",
)

_center_crop_pad_crop_axes_chw¶

import numpy as np
import onnx

node = onnx.helper.make_node(
    "CenterCropPad",
    inputs=["x", "shape"],
    outputs=["y"],
    axes=[1, 2],
)

# Cropping on second dim, padding on third, first stays the same
x = np.random.randn(3, 20, 8).astype(np.float32)
shape = np.array([10, 9], dtype=np.int64)
y = np.zeros([3, 10, 9], dtype=np.float32)
y[:, :, :8] = x[:, 5:15, :]

expect(
    node,
    inputs=[x, shape],
    outputs=[y],
    name="test_center_crop_pad_crop_axes_chw",
)