DICOM PS3.18 2019a - Web Services

6.5.8.2 Behavior

The target resource(s) are rendered according to the query parameters, by applying the transformations according to the appropriate rendering pipeline specified in Section N.2 “Pixel Transformation Sequence” in PS3.4 .

It the target resource is not a single instance, Presentation State Instances contained in the target resource shall not be rendered.

Rendered images shall contain no more than 8 bits per channel.

6.5.8.2.1 Presentation State Instance

If the target resource is a Presentation State Instance, that instance may contain references to one or more series, each of which may contain one or more instances, each of which may contain one or more frames. The response shall return rendered versions of all supported Instances and frames referenced by the Presentation State Instance.

For example, if the Presentation State instance references a multi-frame image, then the response will contain all frames specified by the target resource, or if the Presentation State instance references a series, then the response will contain all instances contained in that series.

If the target resource is a Presentation State Instance, then only the Charset, Annotation, Quality, and Viewport parameters may also be present. If any other Retrieve Rendered Transaction Query Parameters are present the response shall be 400 (Bad Request), and should include a payload containing an appropriate error message.

If the Presentation State Instance contains a Blending Sequence, then the rendered images in the response shall correspond to the frames of the input that have a Blending Sequence Item with a Blending Position (0070,0405) value of UNDERLYING. See Section C.11.14.1.1 “Blending Sequence” in PS3.3 .

The origin server shall render all of the images referenced by the Presentation State in an Acceptable Media Type using the rendering pipeline specified in PS3.4.

If there is more than one image in the response they shall be ordered according to the:

  1. Dimension Index Values (0020,9157) attribute, if present

  2. Image Position (Patient) (0020,0032) attribute, if present

  3. Image Position Volume (0020,9301), if present

  4. Order of the instance references in the presentation state

If the above does not fully specify the ordering of the frames, then the origin server shall resolve any remaining ambiguity in the ordering.

If the Presentation Size Mode is TRUE SIZE it shall be treated as SCALE TO FIT.

If the Presentation Size Mode is SCALE TO FIT, the origin server shall scale the Specified Displayed Area in the Presentation State, maintaining its original aspect ratio, until either the rendered image width is the same as the viewport width or the rendered image height is the same as the viewport height, whichever comes first. In other words, viewport scaling makes the displayed area selection as large as possible, within the viewport, without overflowing the viewport area and without distorting the image. If the viewport parameter is not present, the returned images shall have the dimensions of the Specified Displayed Area.

If the Presentation Size Mode is MAGNIFY, then the referenced images shall be scaled to the Specified Displayed Area in the Presentation State, and then they shall be cropped to the size specified by the "viewport" parameter. If the request does not contain a "viewport" parameter, then the referenced images shall not be cropped.

Any Specified Displayed Area relative annotations in the Presentation State shall be rendered relative to the Specified Displayed Area within the Presentation State, not the size of the viewport.

Though the output of the Presentation State is defined in DICOM to be in P-Values (grayscale values intended for display on a device calibrated to the DICOM Grayscale Standard Display Function PS3.14), the grayscale or color space for the rendered images is not defined by this Standard.

DICOM PS3.18 2019a - Web Services