VHI FILE FORMAT

I. General

AnatLine's Image Database primary function is the storage and delivery of multimedia files. These VHI files contain anatomical formats for Cross Sections, Volumes, Byte Masks, and Rendered images. Each file stores a complex format of data maps, data tables, and image bitmaps.

The Visible Human Image File (VHIF) format supports the delivery of multimedia files from the 3DSystem Image Database. VHIF files contain a file specifier as its file name. The specifier is designed to support automated file management, and image retrieval for client systems. This section defines the internal file format, block structure, and file types.

II. File Format

Each file consists of a File name, a Header, and a set of Information Object Pointers and Information Objects.



File Block Size:

File Name: 16 Bytes
Header Block: 24 Bytes
Information Object Pointer (IOP): 24 Bytes
Information Object Block (IOB): Variable

File Data Structure:

Numerical byte order: Most significant byte first (MSB). Image pixels per row size restricted1 to: 4k,2k,1k,512 (1Restricted to support Cross section reduction factor)

File Name:

Each VHI file name is an encoded identification of the anatomical and image data content. File names represent the major anatomical structure, the other substructures may be featured within the contained bitmap.

Header Block:

This block identifies the file type, version number, file name, number of file object pointers, and the offset, from beginning of file, to the first object pointer.

Information Object Pointer (IOP):

The IOP defines the data content and the offset from beginning of file to its Information Object Block.

Information Object Block (IOB):

The IOB contains text and data blocks, such as data maps, data tables, and bitmaps.

III. File Structure

A. File Name: See file specifier description.

B. Header Block:(unsigned bytes)

Offset Size (Bytes) Comments
00H 4 "VHIF" file suffix
04H 2 Version Number
06H 12 File Name
12H 1 Number of IOPs
13H 4 Undefined
17H 1 First IOP offset

C. Information Object Pointer (IOP)(unsigned bytes):

Offset Size (Bytes) Comments
00H 1 Block type
01H 1 Element data type
02H 1 Bytes per element
03H 2 Elements per row
05H 2 Number of rows
07H 1 Image format
08H 2 Number of z planes
0AH 2 X coordinate offset
0CH 2 Y coordinate offset
0EH 2 Z coordinate offset
10H 4 IOB size (optional)
14H 4 IOB offset

D. Information Object Block (IOB) (unsigned bytes):

Offset Size (Bytes) Comments
Given by IOP Given by IOP Defined by IOP

IV. Header Block Elements

Data field Data Type
File signature ASCII characters (4bytes)
Version numberhexadecimal value (short,2bytes)
File specifierASCII characters (12bytes)
IOP counthexadecimal value (1byte)
UndefinedDefault (int = 0, 4bytes)
First IOP offsethexadecimal value (1byte)

V. Information Object Pointer Elements

A. Block Type:

Byte Value Data Block
00HUndefined
01HText
02HData Table
03HData Map
04HImage Bitmap
05HROI Stack
06HBitmask Stack
07HBytemask Stack
08HRendered Stack
09HVideo
0AHAudio
0BHGraphics
0CHCompressed ByteMask Stack
(UNIX compressed)

B. Element Data Type:

Byte Value Data Type
00HUndefined
01HBinary
02HASCII

C. Bytes per Element:

Byte ValueBytes per element
00HOne bit per element
nnHNumber of bytes

D. Elements per Row:

Byte ValueElements per Row
0000HUndefined
nnnnHNumber of data columns

E. Number of Rows:

Byte ValueNumber of Rows
0000HUndefined
nnnnHNumber of data rows

F. Image Format:

Byte ValueFormat
00HCoded Data
01HBinary Bitmap
02HMonochrome Bitmap
03H8 bit color
04HRGB interleaved
05HRGB non-interleaved
06HGIF
07HTIF
08HJPG
O9HMPG
OAHQT (quick time)

G. Number of Z Planes:

Byte ValueNumber of Z Planes
nnnnHNumber of separate bitmap planes

H. X Coordinate Offset:(Bitmap data only)

Byte ValueX Coordinate Offset
nnnnHImage plane pixel offset from
top left corner of full dataset.

I. Y Coordinate Offset:(Bitmap data only)

Byte ValueY Coordinate Offset
nnnnHImage plane pixel offset from
top left corner of full dataset.

J. Z coordinate Offset:(Bitmap data only)

Byte ValueZ Coordinate Offset
nnnnHOffset from top plane of full dataset.

K. IOB Size: Byte size of the IOB.

L. IOB Offset: Offset from beginning of file to IOB.

VI. Information Object Block Elements

Information Object Blocks contain text blocks with descriptive information, and data blocks with data maps, tables, and bitmaps.

TEXT BLOCK:

The first Information Object Block in each file is a text block. Each text block is formatted with structured, and narrative ASCII text. The structured section includes anatomical,specimen, production, and image data.

A. Structured Data Block:

Line 1 Anatomical Label: (Label Data)
Line 2 UMLS UI: 8 Bytes (ie. C0018787)
Line 3 Anatomical Data: Blank (future use)
Line 4 Anatomical Data: Blank (future use)

Line 5

Anatomical Data: Blank (future use)
Line 6 Anatomical Data: Blank (future use)
Line 7 Anatomical Data: Blank (future use)
Line 8 Specimen Data: Blank (future use)
Line 9 Specimen Data: Blank (future use)
Line 10 Sex: (Male, Female)
Line 11 Race: (Caucasian,Black,etc)
Line 12 Age: No. years No. months
Line 13 Height: No. feet No. inches
Line 14 Weight: No. lbs
Line 15 Image Data Blank (future use)
Line 16 Image Data: Blank (future use)
Line 17 Image Data: Blank (future use)
Line 18 Image Data: Blank (future use)
Line 19 Image capture: (70mm film,CCD,35mm film)
Line 20 Pixel dimension: x:0.144mm,y:0.144mm,z:1.0mm
Line 21 Post Image Process: 70mm film to digital data
Line 22 Embedded File: GIF,TIF,JPG,etc
Line 23 File Build Date: Date String (mm/dd/yyyy)
Line 24 File Data: Blank (future use)
Line 25 File Data: Blank (future use)

B. Free Text Block:

Background Information: (to be specified)
Anatomical Information: (to be specified)
Specimen Information: (see specimen editor data)
Producer Information: (see producer editor data)
Other Information: (to be specified)

DATA BLOCKS:

Data blocks are unique to the file types (see below).



VII. File Types

The current version of the VHIF file format defines four file types:

A. Cross Section file:
Single plane full color bitmaps of anatomical image sections alone the body axis. Each file contains a header block, text block of descriptive information, and three data blocks.

B. Volume of Interest file: VOIs are collections of full color image bitmaps(Regions of Interest) along the z-plane containing a defined anatomical structure. Enclosed with the VOI is a supplementary stack of segmented binary overlays, and a segment table.

C. Rendered file: Rendered images are 2D representations of 3D volume and surface rendered images.

D. Segmented Byte Mask file: Byte Masks are collections of binary bitmaps of anatomical structures. These bitmaps are image overlays for cross section images.