Helper methods for Fourier processing (sarpy.processing.sicd.fft_base)

Helper classes and methods for Fourier processing schemes.

class sarpy.processing.sicd.fft_base.FFTCalculator(reader: str | SICDTypeReader, dimension: int = 0, index: int = 0, block_size: None | int | float = 50)

Bases: FullResolutionFetcher

Base Fourier processing calculator class.

This is intended for processing schemes where full resolution is required along the processing dimension, so sub-sampling along the processing dimension does not decrease the amount of data which must be fetched.

property dimension: int

The dimension along which to perform the color subaperture split.

Type:

int

property index: int

The index of the reader.

Type:

int

property fill: float

The fill factor for the fourier processing.

Type:

float

property block_size: float | None

The approximate processing block size in MB, where None represents processing in a single block.

Type:

None|float

property block_size_in_bytes: int | None

The approximate processing block size in bytes.

Type:

None|int

property data_size: Tuple[int, ...]

The data size for the reader at the given index.

Type:

Tuple[int, …]

static extract_blocks(the_range: slice | Tuple[int, int, int], index_block_size: None | int | float) → Tuple[List[Tuple[int, int, int]], List[Tuple[int, int]]]

Convert the single range definition into a series of range definitions in keeping with fetching of the appropriate block sizes.

Parameters:

• the_range (slice|Tuple[int, int, int]) – The input (off processing axis) range.

• index_block_size (None|int|float) – The size of blocks (number of indices).

Returns:

• range_definitions (List[Tuple[int, int, int]]) – The sequence of range definitions (start index, stop index, step) relative to the overall image.

• limit_indices (List[Tuple[int, int]]) – The sequence of start/stop indices for positioning of the given range relative to the original range.

get_fetch_block_size(start_element: int, stop_element: int) → int

Gets the fetch block size for the given full resolution section. This assumes that the fetched data will be 8 bytes per pixel, in accordance with single band complex64 data.

Parameters:

• start_element (int) –

• stop_element (int) –

Return type:

int

property reader: SICDTypeReader

The reader instance.

Type:

SICDTypeReader

property sicd: SICDType

The sicd structure.

Type:

SICDType

sarpy.processing.sicd.fft_base.fft_sicd(array: ndarray, dimension: int, sicd: SICDType) → ndarray

Apply the forward one-dimensional forward fft to data associated with the given sicd along the given dimension/axis, in accordance with the sign populated in the SICD structure (default is -1).

Parameters:

• array (numpy.ndarray) – The data array, which must be two-dimensional and complex.

• dimension (int) – Must be one of 0, 1.

• sicd (SICDType) – The associated SICD structure.

Return type:

numpy.ndarray

sarpy.processing.sicd.fft_base.ifft_sicd(array: ndarray, dimension: int, sicd: SICDType) → ndarray

Apply the inverse one-dimensional fft to data associated with the given sicd along the given dimension/axis.

Parameters:

• array (numpy.ndarray) – The data array, which must be two-dimensional and complex.

• dimension (int) – Must be one of 0, 1.

• sicd (SICDType) – The associated SICD structure.

Return type:

numpy.ndarray

sarpy.processing.sicd.fft_base.fft2_sicd(array: ndarray, sicd: SICDType) → ndarray

Apply the forward two-dimensional fft (i.e. both axes) to data associated with the given sicd.

Parameters:

• array (numpy.ndarray) – The data array, which must be two-dimensional and complex.

• sicd (SICDType) – The associated SICD structure.

Return type:

numpy.ndarray

sarpy.processing.sicd.fft_base.ifft2_sicd(array: ndarray, sicd: SICDType) → ndarray

Apply the inverse two-dimensional fft (i.e. both axes) to data associated with the given sicd.

Parameters:

• array (numpy.ndarray) – The data array, which must be two-dimensional and complex.

• sicd (SICDType) – The associated SICD structure.

Return type:

numpy.ndarray