D DICOM Image Processing

This appendix describes image processing operations for DICOM content.

See Oracle Multimedia Reference for a complete list of image processing operators and details on each operator. See Chapter 5 and Chapter 6 for reference information about the processCopy( ) method.

D.1 The frame Image Processing Operator

The frame operator is new for DICOM image processing. You can use the frame operator to extract a specific frame image from a multiframe DICOM image. You can also combine the frame operator with other image processing operators, such as scale and rotate, to perform multiple operations on a single frame extracted from a multiframe DICOM image.

To extract a specific frame by the number of the frame, use the following syntax:

frame = <frame number>

If the specified frame number is less than 1 or greater than the maximum number of frames in the DICOM image, the attempted operation returns an invalid frame exception. The frame operator can be used for DICOM images with only one frame. However, in this case, the value for the frame number must always be 1.

D.2 Other Image Processing Operators

Other image processing operators include fileFormat, contentFormat, compressionFormat, cut, scale, and rotate. See Oracle Multimedia Reference for a complete list of image processing operators and details on each operator.

D.3 DICOM Image Content and Compression Formats

Photometric interpretation of DICOM image content is specified by the tag <00280004>. Table D-1 shows the supported photometric interpretations for the processCopy( ) method with DICOM images.

Table D-1 DICOM Content Photometric Interpretations

Action	Supported Photometric Interpretation Values
READING	MONOCHROME1, MONOCHROME2, RGB, and PALETTECOLOR
WRITING	MONOCHROME1, MONOCHROME2, and RGB

For the Action READING, DICOM images with the listed photometric interpretation values can be decoded and the pixel data can be correctly extracted. For the Action WRITING, DICOM images with the listed photometric interpretation values can be encoded and the pixel data can be correctly written with the corresponding photometric interpretations.

Compression format type in DICOM images is specified by the transfer syntax UID value or the tag <00020010>. Table D-2 shows the supported compression formats for the processCopy( ) method with DICOM images.

Table D-2 DICOM Content Compression Formats

Action	Supported Compression Format Values
READING	JPEG, JPEG 2000^Foot 1, RLE, and RAW^Foot 2
WRITING	JPEG, JPEG 2000^Foot 3, and RAW^Foot 4

^Footnote 1With JAI image IO installations (see Appendix C)

^Footnote 2With 8-bit, 12-bit, 16-bit, and other bits

^Footnote 3With JAI image IO installations (see Appendix C)

^Footnote 4With 8-bit, 12-bit, and 16-bit

For the Action READING, DICOM images with the listed compression format values can be decoded and the pixel data can be correctly decompressed. For the Action WRITING, DICOM images with the compression format values can be encoded and the pixel data can be correctly compressed with the correspondent compression format types.

To specify the compression format for the processCopy( ) method, use the compressionFormat operator. If the image is not compressed (the compression format value is RAW), the encoding bits of each pixel are specified in the user's metadata, which is passed as one argument of the processCopy( ) method. See Chapter 5 and Chapter 6 for reference information about the processCopy( ) method and for details about the compressionFormat operator.

D.4 Multiframe Image Processing and Creation

Oracle Multimedia supports the creation and processing of multiframe DICOM images.

To process a single frame in a multiframe DICOM image, specify the frame within the frame operator statement in the processCopy command (see the example of this syntax in Section D.1). You can also combine the frame operator with other operators, such as scale and rotate, to perform multiple operations on a single frame extracted from a multiframe DICOM image. See Oracle Multimedia Reference for a complete list of image processing operators and details on each operator.

To create a multiframe DICOM image, use the following syntax:

frame = ALL

Alternatively, you can combine the frame operator with other operators, such as scale and rotate, to perform multiple operations on all the frames in a multiframe DICOM image.

You can also use the frame = ALL syntax to specify processing operations to be performed on single-frame DICOM images.

D.5 Order of Precedence with processCopy( ) Method Arguments

When you use the processCopy( ) method to process a DICOM image to another DICOM image, you can specify the optional metadata argument, SYS.XMLTYPE. The processCopy( ) method uses this metadata argument to specify the encoding rules for the output DICOM image. If a conflict exists between the command argument and the metadata argument, the command argument takes precedence over the metadata argument. The encoding information in the output DICOM image is updated with the result of the processing operation, as specified by the command argument and the metadata argument (in that order).