decompressShape

Decompresses a gradient or pulse shape that has been compressed using a run-length encoding scheme on its derivative. The input shape is a structure containing the compressed waveform and the number of samples in the uncompressed waveform. The function reconstructs the original waveform by iteratively expanding the run-length encoded segments.

Syntax

function w = decompressShape(shape, forceDecompression)

Calling Pattern

mr.decompressShape(...)

Parameters

Required Parameters

Name	Type	Description	Example	Units
shape	struct	Structure containing the compressed waveform data. Must have fields 'num_samples' (number of samples in the uncompressed waveform) and 'data' (the compressed waveform data).	{ 'num_samples': 1000, 'data': [1, 0, 2, 0, 0, 3, ... ] }

Optional Parameters

Name	Type	Default	Description	Example
forceDecompression	logical	false	If true, forces decompression even if the input shape appears to be already uncompressed (i.e., the number of samples matches the length of the compressed data). Valid values: true, false	true

Returns

Output	Type	Description
w	double	A vector containing the decompressed waveform.

Examples

% Decompress RF magnitude from compressed shape data
shapeData = obj.shapeLibrary.data(magShape).array;
compressed.num_samples = shapeData(1);
compressed.data = shapeData(2:end);
mag = mr.decompressShape(compressed);

% Decompress phase data for RF pulse reconstruction
phase = mr.decompressShape(compressed);

% Force decompression of waveform data
w = mr.decompressShape(shape, true);

See Also

compressShape