From 3ac0987a61ea31a9df5f325949de40908a3307af Mon Sep 17 00:00:00 2001 From: malaterre Date: Mon, 27 Jun 2005 00:25:31 +0000 Subject: [PATCH] ENH: adding notes about thumbnails in GEMS file --- Doc/GE_ImageThumbnails | 127 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 Doc/GE_ImageThumbnails diff --git a/Doc/GE_ImageThumbnails b/Doc/GE_ImageThumbnails new file mode 100644 index 00000000..3c838be2 --- /dev/null +++ b/Doc/GE_ImageThumbnails @@ -0,0 +1,127 @@ + +GE Medical Systems +PATHSPEEDâ"¢ PACS 8.0 CONFORMANCE STATEMENT + +REV 1, SEPTEMBER 2000 + +IIS FP 10282 + +7Å"48 + +7. APPENDIX A: IMAGE THUMBNAILS ADDED TO DICOM IMAGES + +7.1 IMAGE THUMBNAIL + +PathSpeedâ"¢ PACS will create a thumbnail for each DICOM Image SOP Instance of the following +Photometric Interpretation values: + +* MONOCHROME1 + +* MONOCRHOEM2 + +* RGB + +The thumbnail is derived from the original pixel data by downscaling the image size to 128 Ã- 128 +pixels or less, and added to the original SOP Instance with a private sequence data element in the +DICOM Image SOP Instance. + +One thumbnail is created per DICOM image. For a multi-frame image, only one thumbnail is created +from the center frame. The number of the frame, which is used for the thumbnail creation is included in +the Image SOP Instance (see Section 7.3). +In PathSpeedâ"¢ PACS, the thumbnails are used by the PathSpeedâ"¢ Web display application for image +navigation when browsing through a set of images. With the information published in this Appendix, a +DICOM application receiving the images from PathSpeedâ"¢ PACS can also explore the thumbnail data +encoded in the Image SOP Instances. + +7.2 IMAGE THUMBNAIL COMPRESSION + +The thumbnail is compressed with 8 bits or 12 bits JPEG lossy compression format, depending on the +stored 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 one +byte 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 two +bytes 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 is +first shifted to fit into the 12 bits scope and then stored two bytes per pixel. The thumbnail is +compressed by JPEG 12-bits lossy compression. The bits shifted is saved in the GE Private Image +Thumbnail Sequence, as specified in the next section. +All thumbnails are represented in the unsigned format (either byte or two-bytes (12 bits) integer). If an +Image SOP Instance contains a signed pixel data element, the thumbnail pixel data will be offset to the +unsigned scope. The offset added is saved in the GE Private Image Thumbnail Sequence, as specified +in the next section. + +Page 55 + +GE Medical Systems +PATHSPEEDâ"¢ PACS 8.0 CONFORMANCE STATEMENT + +REV 1, SEPTEMBER 2000 + +IIS FP 10282 + +7Å"49 + +7.3 IMAGE THUMBNAIL ENCODING + +PathSpeedâ"¢ PACS adds a private sequence data element (GE Private Image Thumbnail Sequence) to +an Image SOP Instance for the thumbnail encoding. There is no any change to the existing data +attributes of the SOP Instance. +The GE Private Image Thumbnail Sequence is specified in the following table. +Data Element + +Tag VR VM Description + +Private Creator ID (0009,00xx) LO 1 GEIIS, Reserve xx00-xxFF of group 0009 in the SOP Instance. +GE Private Image Thumbnail Sequence (0009,xx10) SQ 1 Always only one item present + +> Sample per Pixel (0028,0002) US 1 Copy from the original SOP Instance +> Photometric Interpretation (0028,0004) CS 1 Thumbnail Photometric Interpretation. + Enumerated Values: + MONOCHROME1, + MONOCHROME2, RGB +> Planar Configuration (0028,0006) US 1 Thumbnail Planar Configuration. Always 0, if present. +> Number of Frames (0028,0008) IS 1 Copy from the original SOP Instance. The thumbnail itself is always single frame. +> Rows (0028,0010) US 1 Thumbnail Rows of Image Matrix, ≤ 128. +> Columns (0028,0011) US 1 Thumbnail Columns of Image Matrix, ≤ 128. +> Bits Allocated (0028,0100) US 1 Copy from the original SOP Instance +> Bits Stored (0028,0101) US 1 Copy from the original SOP Instance. If this value is 8 or less, the thumbnail JPEG stream is 8 bits compressed, otherwise, it is 12 bits compressed. +> High Bit (0028,0102) US 1 Copy from the original SOP Instance +> Pixel Representation (0028,0103) US 1 Copy from the original SOP Instance +> Largest Image Pixel Value (0028,0107) US/ SS 1 Copy from the original SOP Instance +> Pixel Padding Value (0028,0120) US/ SS 1 Copy from the original SOP Instance +> Window Center (0028,1050) DS 1-n Copy from the original SOP Instance + +Page 56 + + +GE Medical Systems +PATHSPEEDâ"¢ PACS 8.0 CONFORMANCE STATEMENT + +REV 1, SEPTEMBER 2000 + +IIS FP 10282 + +7Å"50 + +> Window Level (0028,1051) DS 1-n Copy from the original SOP Instance +> Rescale Intercept (0028,1052) DS 1 Copy from the original SOP Instance +> Rescale Slope (0028,1053) DS 1 Copy from the original SOP Instance +> Private Creator ID (0029,0010) LO 1 â€"GEIIS“, Reserve 1000-10FF of group 0029 in this item. +> Shift Count (0029,1010) UL 1 Number of bits pixel values were shifted down to get them into the 12 bits range before JPEG compression. +> Offset (0029,1012) UL 1 Value added to pixel values to convert them from signed to unsigned values before JPEG compression. +> Actual Frame Number (0029,1014) UL 1 Actual frame number of image the thumbnail was generated from. For multi-frame images, this should represent the center frame. Only one thumbnail is created for the entire multi-frame image. +> Private Creator ID (7FD1,0010) LO 1 â€"GEIIS“, Reserve 1000-10FF of group 7FD1 in this item. +> GE IIS Compression Type (7FD1,1010) UL 1 PathSpeedâ"¢ PACS internally used data compression code. Always 26 for thumbnail +> Pixel Data (7FE0,0010) OB 1 8 bits or 12 bits JPEG lossy compressed thumbnail image pixel data stream. + +TABLE +7-1: SPECIFICATION OF GE PRIVATE IMAGE THUMBNAIL SEQUENCE + +The GE Private Image Thumbnail Sequence includes a number of standard data elements directly +copied from the original Image SOP Instance, to which the sequence is added. These data elements are +marked as Copy from the original SOP Instance in Table 7-1. These data elements provide the +original pixel data context from that the thumbnail has been derived. Note that they do not contain the +values specific to the thumbnail. +The GE Private Image Thumbnail Sequence uses a number of standard data elements to describe the +properties of the thumbnail pixel data. Note that these data elements in this sequence really contain the +values specific to the thumbnail, but not to the original image pixel data -- 2.45.1