Photometric Interpretations

DICOM allows various relationships between the pixel data and how the image should be displayed. The values here are found in element 0028,0004 and every image should have that value.

All the following are supported by DicomObjects

Contents

MONOCHROME2

  • Normal Monochrome image
  • Higher pixel values are displayed as whiter

MONOCHROME1

  • Reversed Monochrome image
  • Higher pixel values are displayed as blacker
  • Only commonly used for CR/DR images

PALETTE COLOUR

  • 8 or 16 bits per pixel
  • Palettes are stored in separate attributes
  • Only commonly used for Doppler US

RGB

  • The most common colour format

YBR_FULL

  • Alternative colour format stored as Luminance (Y) and two chroma (R - "redness" and B- "blueness") values.

YBR_FULL_422

The YBR_FULL_422 photometric interpretation is commonly used with lossy JPEG data.

Each pair of pixels occupies 4 bytes, each pixel having its own luminance (Y) value, but sharing the chroma (R - "redness" and B- "blueness") values.

In theory, this is also allowed for uncompressed data, but experience shows that many cheaper viewers do not support it. In uncompressed data, the values are stored as "packed cells", as follows:

Y Y B R Y Y B R Y Y B R....

YBR_PARTIAL_422

  • As YBR_FULL_422 but with slightly different numerical relationship between stored and displayed values.

YBR_RCT

  • Reversible Colour transformation
  • Used for JPEG 2000 lossless

YBR_ICT

  • Irreversible Colour transformation
  • Used for JPEG 2000 lossy
  • Effectively the same as YBR_FULL
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