Deflated Image Frame Compression#

The requirements for Deflated Image Frame Compression encoding are defined in Section 8.2.16 and Annex A.4.13 in Part 5 of the DICOM Standard. The underlying algorithm is the Deflate compression method.

Deflated Image Frame Compression is primary intended for single-bit segmentation encoding, however there are no restrictions on using it with other types of pixel data.

Valid Image Pixel Parameters#

To ensure you have the correct Photometric Interpretation when encoding using Deflated Image Frame Compression, the uncompressed pixel data should already be in the corresponding color space:

  • If your uncompressed pixel data is grayscale (intensity) based:

    • Use MONOCHROME1 if the minimum intensity value should be displayed as white.

    • Use MONOCHROME2 if the minimum intensity value should be displayed as black.

  • If your uncompressed pixel data uses a single sample per pixel and is an index to the Red, Green and Blue Palette Color Lookup Tables:

    • Use PALETTE COLOR.

  • If your uncompressed pixel data is in RGB color space:

    • For Photometric Interpretation RGB nothing else is required.

    • For Photometric Interpretation YBR_FULL data must be converted into YCbCr color space, however the conversion operation is lossy.

  • If your uncompressed pixel data is in YCbCr color space:

    • For Photometric Interpretation RGB the pixel data must first be converted into RGB color space, however the conversion operation is lossy.

    • For Photometric Interpretation YBR_FULL nothing else is required.

Available Plugins#

Encoder

Plugins

Name

Added

DeflatedImageFrameCompressionEncoder

pydicom

v3.1

Examples#

Compressing grayscale pixel data in-place:

>>> from pydicom import examples
>>> from pydicom.uid import DeflatedImageFrameCompression
>>> ds = examples.ct
>>> ds.SamplesPerPixel
1
>>> ds.PhotometricInterpretation
'MONOCHROME2'
>>> ds.BitsAllocated
16
>>> ds.PixelRepresentation
1
>>> ds.compress(DeflatedImageFrameCompression)
>>> len(ds.PixelData)
22288