nvidia.dali.fn.crop

nvidia.dali.fn.crop(*inputs, **kwargs)

Crops the images with the specified window dimensions and window position (upper left corner).

This operator allows sequence inputs and supports volumetric data.

Supported backends

• ‘cpu’

• ‘gpu’

Parameters:

input (TensorList ('HWC', 'CHW', 'DHWC', 'CDHW', 'FHWC', 'FCHW', 'CFHW', 'FDHWC', 'FCDHW', 'CFDHW')) – Input to the operator.

Keyword Arguments:

• bytes_per_sample_hint (int or list of int, optional, default = [0]) –

  Output size hint, in bytes per sample.

  If specified, the operator’s outputs residing in GPU or page-locked host memory will be preallocated to accommodate a batch of samples of this size.

• crop (float or list of float or TensorList of float, optional) –

  Shape of the cropped image, specified as a list of values (for example, (crop_H, crop_W) for the 2D crop and (crop_D, crop_H, crop_W) for the volumetric crop).

  Providing crop argument is incompatible with providing separate arguments such as crop_d, crop_h, and crop_w.

• crop_d (float or TensorList of float, optional, default = 0.0) –

  Applies only to volumetric inputs; cropping window depth (in voxels).

  crop_w, crop_h, and crop_d must be specified together. Providing values for crop_w, crop_h, and crop_d is incompatible with providing the fixed crop window dimensions (argument crop).

• crop_h (float or TensorList of float, optional, default = 0.0) –

  Cropping the window height (in pixels).

  Providing values for crop_w and crop_h is incompatible with providing fixed crop window dimensions (argument crop).

• crop_pos_x (float or TensorList of float, optional, default = 0.5) –

  Normalized (0.0 - 1.0) horizontal position of the cropping window (upper left corner).

  The actual position is calculated as crop_x = crop_x_norm * (W - crop_W), where crop_x_norm is the normalized position, W is the width of the image, and crop_W is the width of the cropping window.

  See rounding argument for more details on how crop_x is converted to an integral value.

• crop_pos_y (float or TensorList of float, optional, default = 0.5) –

  Normalized (0.0 - 1.0) vertical position of the start of the cropping window (typically, the upper left corner).

  The actual position is calculated as crop_y = crop_y_norm * (H - crop_H), where crop_y_norm is the normalized position, H is the height of the image, and crop_H is the height of the cropping window.

  See rounding argument for more details on how crop_y is converted to an integral value.

• crop_pos_z (float or TensorList of float, optional, default = 0.5) –

  Applies only to volumetric inputs.

  Normalized (0.0 - 1.0) normal position of the cropping window (front plane). The actual position is calculated as crop_z = crop_z_norm * (D - crop_D), where crop_z_norm is the normalized position, D is the depth of the image and crop_D is the depth of the cropping window.

  See rounding argument for more details on how crop_z is converted to an integral value.

• crop_w (float or TensorList of float, optional, default = 0.0) –

  Cropping window width (in pixels).

  Providing values for crop_w and crop_h is incompatible with providing fixed crop window dimensions (argument crop).

• dtype (nvidia.dali.types.DALIDataType, optional) –

  Output data type.

  Supported types: FLOAT, FLOAT16, and UINT8.

  If not set, the input type is used.

• fill_values (float or list of float, optional, default = [0.0]) –

  Determines padding values and is only relevant if out_of_bounds_policy is set to “pad”.

  If a scalar value is provided, it will be used for all the channels. If multiple values are provided, the number of values and channels must be identical (extent of dimension C in the layout) in the output slice.

• image_type (nvidia.dali.types.DALIImageType) –

  Warning

  The argument image_type is no longer used and will be removed in a future release.

• out_of_bounds_policy (str, optional, default = ‘error’) –

  Determines the policy when slicing the out of bounds area of the input.

  Here is a list of the supported values:

  • "error" (default): Attempting to slice outside of the bounds of the input will produce an error.

  • "pad": The input will be padded as needed with zeros or any other value that is specified with the fill_values argument.

  • "trim_to_shape": The slice window will be cut to the bounds of the input.

• preserve (bool, optional, default = False) – Prevents the operator from being removed from the graph even if its outputs are not used.

• rounding (str, optional, default = ‘round’) –

  Determines the rounding function used to convert the starting coordinate of the window to an integral value (see crop_pos_x, crop_pos_y, crop_pos_z).

  Possible values are:

  • "round" - Rounds to the nearest integer value, with halfway cases rounded away from zero.
  • "truncate" - Discards the fractional part of the number (truncates towards zero).

• seed (int, optional, default = -1) –

  Random seed.

  If not provided, it will be populated based on the global seed of the pipeline.

• output_dtype (nvidia.dali.types.DALIDataType) –

  Warning

  The argument output_dtype is a deprecated alias for dtype. Use dtype instead.