Centricity PACS Version 1.0 CONFORMANCE STATEMENT for ...

GEMS INFORMATION TECHNOLOGIESCENTRICITY PACS 1.0 CONFORMANCE STATEMENTREV 0, MAY 2002 IIS FP 106178. APPENDIX A: IMAGE THUMBNAILS ADDED TO DICOM IMAGES8.1 IMAGE THUMBNAILCentricity PACS will create a thumbnail for each DICOM Image SOP Instance of the followingPhotometric Interpretation values:xxxMONOCHROME1MONOCRHOEM2RGBThe thumbnail is derived from the original pixel data by downscaling the image size to 128 u 128pixels or less, and added to the original SOP Instance with a private sequence data element in theDICOM Image SOP Instance.One thumbnail is created per DICOM image. For a multi-frame image, only one thumbnail is createdfrom the center frame. The number of the frame, which is used for the thumbnail creation is included inthe Image SOP Instance (see Section 8.3).In Centricity PACS, the thumbnails are used by the Centricity Web display application for imagenavigation when browsing through a set of images. With the information published in this Appendix, aDICOM application receiving the images from Centricity PACS can also explore the thumbnail dataencoded in the Image SOP Instances.8.2 IMAGE THUMBNAIL COMPRESSIONThe thumbnail is compressed with 8 bits or 12 bits JPEG lossy compression format, depending on thestored pixel depth of the original images.For all Image SOP Instances with bits stored equal to or less then 8, the thumbnail image is stored onebyte per pixel and compressed by JPEG 8-bits lossy compression.For all Image SOP Instances with bits stored equal to or less 12, the thumbnail image is stored twobytes per pixel and compressed by JPEG 12-bits lossy compression.For all Image SOP Instances with bits stored greater than 12, the pixel data of the thumbnail image isfirst shifted to fit into the 12 bits scope and then stored two bytes per pixel. The thumbnail iscompressed by JPEG 12-bits lossy compression. The bits shifted is saved in the GE Private ImageThumbnail Sequence, as specified in the next section.All thumbnails are represented in the unsigned format (either byte or two-bytes (12 bits) integer). If anImage SOP Instance contains a signed pixel data element, the thumbnail pixel data will be offset to theunsigned scope. The offset added is saved in the GE Private Image Thumbnail Sequence, as specifiedin the next section.8–63