3 PATHSPEEDâ"¢ PACS 8.0 CONFORMANCE STATEMENT
11 7. APPENDIX A: IMAGE THUMBNAILS ADDED TO DICOM IMAGES
15 PathSpeedâ"¢ PACS will create a thumbnail for each DICOM Image SOP Instance of the following
16 Photometric Interpretation values:
24 The thumbnail is derived from the original pixel data by downscaling the image size to 128 Ã- 128
25 pixels or less, and added to the original SOP Instance with a private sequence data element in the
26 DICOM Image SOP Instance.
28 One thumbnail is created per DICOM image. For a multi-frame image, only one thumbnail is created
29 from the center frame. The number of the frame, which is used for the thumbnail creation is included in
30 the Image SOP Instance (see Section 7.3).
31 In PathSpeedâ"¢ PACS, the thumbnails are used by the PathSpeedâ"¢ Web display application for image
32 navigation when browsing through a set of images. With the information published in this Appendix, a
33 DICOM application receiving the images from PathSpeedâ"¢ PACS can also explore the thumbnail data
34 encoded in the Image SOP Instances.
36 7.2 IMAGE THUMBNAIL COMPRESSION
38 The thumbnail is compressed with 8 bits or 12 bits JPEG lossy compression format, depending on the
39 stored pixel depth of the original images.
40 For all Image SOP Instances with bits stored equal to or less then 8, the thumbnail image is stored one
41 byte per pixel and compressed by JPEG 8-bits lossy compression.
42 For all Image SOP Instances with bits stored equal to or less 12, the thumbnail image is stored two
43 bytes per pixel and compressed by JPEG 12-bits lossy compression.
44 For all Image SOP Instances with bits stored greater than 12, the pixel data of the thumbnail image is
45 first shifted to fit into the 12 bits scope and then stored two bytes per pixel. The thumbnail is
46 compressed by JPEG 12-bits lossy compression. The bits shifted is saved in the GE Private Image
47 Thumbnail Sequence, as specified in the next section.
48 All thumbnails are represented in the unsigned format (either byte or two-bytes (12 bits) integer). If an
49 Image SOP Instance contains a signed pixel data element, the thumbnail pixel data will be offset to the
50 unsigned scope. The offset added is saved in the GE Private Image Thumbnail Sequence, as specified
56 PATHSPEEDâ"¢ PACS 8.0 CONFORMANCE STATEMENT
64 7.3 IMAGE THUMBNAIL ENCODING
66 PathSpeedâ"¢ PACS adds a private sequence data element (GE Private Image Thumbnail Sequence) to
67 an Image SOP Instance for the thumbnail encoding. There is no any change to the existing data
68 attributes of the SOP Instance.
69 The GE Private Image Thumbnail Sequence is specified in the following table.
74 Private Creator ID (0009,00xx) LO 1 GEIIS, Reserve xx00-xxFF of group 0009 in the SOP Instance.
75 GE Private Image Thumbnail Sequence (0009,xx10) SQ 1 Always only one item present
77 > Sample per Pixel (0028,0002) US 1 Copy from the original SOP Instance
78 > Photometric Interpretation (0028,0004) CS 1 Thumbnail Photometric Interpretation.
82 > Planar Configuration (0028,0006) US 1 Thumbnail Planar Configuration. Always 0, if present.
83 > Number of Frames (0028,0008) IS 1 Copy from the original SOP Instance. The thumbnail itself is always single frame.
84 > Rows (0028,0010) US 1 Thumbnail Rows of Image Matrix, ≤ 128.
85 > Columns (0028,0011) US 1 Thumbnail Columns of Image Matrix, ≤ 128.
86 > Bits Allocated (0028,0100) US 1 Copy from the original SOP Instance
87 > 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.
88 > High Bit (0028,0102) US 1 Copy from the original SOP Instance
89 > Pixel Representation (0028,0103) US 1 Copy from the original SOP Instance
90 > Largest Image Pixel Value (0028,0107) US/ SS 1 Copy from the original SOP Instance
91 > Pixel Padding Value (0028,0120) US/ SS 1 Copy from the original SOP Instance
92 > Window Center (0028,1050) DS 1-n Copy from the original SOP Instance
98 PATHSPEEDâ"¢ PACS 8.0 CONFORMANCE STATEMENT
100 REV 1, SEPTEMBER 2000
106 > Window Level (0028,1051) DS 1-n Copy from the original SOP Instance
107 > Rescale Intercept (0028,1052) DS 1 Copy from the original SOP Instance
108 > Rescale Slope (0028,1053) DS 1 Copy from the original SOP Instance
109 > Private Creator ID (0029,0010) LO 1 â€"GEIIS“, Reserve 1000-10FF of group 0029 in this item.
110 > 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.
111 > Offset (0029,1012) UL 1 Value added to pixel values to convert them from signed to unsigned values before JPEG compression.
112 > 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.
113 > Private Creator ID (7FD1,0010) LO 1 â€"GEIIS“, Reserve 1000-10FF of group 7FD1 in this item.
114 > GE IIS Compression Type (7FD1,1010) UL 1 PathSpeedâ"¢ PACS internally used data compression code. Always 26 for thumbnail
115 > Pixel Data (7FE0,0010) OB 1 8 bits or 12 bits JPEG lossy compressed thumbnail image pixel data stream.
118 7-1: SPECIFICATION OF GE PRIVATE IMAGE THUMBNAIL SEQUENCE
120 The GE Private Image Thumbnail Sequence includes a number of standard data elements directly
121 copied from the original Image SOP Instance, to which the sequence is added. These data elements are
122 marked as Copy from the original SOP Instance in Table 7-1. These data elements provide the
123 original pixel data context from that the thumbnail has been derived. Note that they do not contain the
124 values specific to the thumbnail.
125 The GE Private Image Thumbnail Sequence uses a number of standard data elements to describe the
126 properties of the thumbnail pixel data. Note that these data elements in this sequence really contain the
127 values specific to the thumbnail, but not to the original image pixel data