itk::image_dimension Struct Reference

Public Attributes
short int	dim [8]
char	vox_units [4]
char	cal_units [8]
short int	unused1
short int	datatype
short int	bitpix
short int	dim_un0
float	pixdim [8]
float	vox_offset
float	roi_scale
float	funused1
float	funused2
float	cal_max
float	cal_min
int	compressed
int	verified
int	glmax
int	glmin

Detailed Description

the organization and size of images. These elements enable IO routines to reference images by volume and slice number.

• (c) Copyright, 1986-1995
• Biomedical Imaging Resource
• Mayo Foundation

Member Data Documentation

short int itk::image_dimension::bitpix

Bits per pixel. This field must agree with the datatype and data_type fields.

See also

DataTypeSizes

float itk::image_dimension::cal_max

The parameters 'cal_max' and 'cal_min' provided a mechanism for rescaling the voxel values into a different range of value representation. This string allowed whatever the range of value representation was to be expressed with these string characters. Never really used in a robust manner.

float itk::image_dimension::cal_min

See also

image_dimension::cal_max

char itk::image_dimension::cal_units[8]

Specifies the name of the calibration unit, valid values are "mm","cm" and "in". NOTE: if no match is found, "mm" is assumed.

int itk::image_dimension::compressed

Valid values are only 0 and 1. A 0 value indicates that the file is uncompressed. A 1 value indicates that the *.img file has been compress with the standard Unix 'compress' utility.

• filename, compressed value, description
• basename.img, 0, uncompressed image file of size
• basename.img, 1, compressed image file using unix 'compress' utility
• basename.img.Z, 0, compressed image using unix 'compress' utiltiy
• basename.img.gz, 0, compressed image file gzip utility
• basename.img.Z, 1, invalid setting
• basename.img.gz, 1, invalid setting

short int itk::image_dimension::datatype

A short int that defines the type of data being stored. NOTE: THIS MUST BE FILLED IN. This is the field that most applications use to determine the data storage type. Valid values are defined by DataTypeKeyValues.

See also

DataTypeKeyValues

short int itk::image_dimension::dim[8]

Array of image dimensions

• dim[0] number of dimensions; usually 4
• dim[1] image X dimension, i.e. number of voxels per row (adjacent memory locations)
• dim[2] image Y dimension, i.e. number of rows per slice
• dim[3] Volume Z dimension, i.e. number of slices per volume
• dim[4] Number of time points, i.e. number of volumes per series
• . . .
• dim[7] volumes in file, i.e. number of volumes per series

short int itk::image_dimension::dim_un0

Unused value for future expansion.

float itk::image_dimension::funused1

Unused, for future expansion

float itk::image_dimension::funused2

Unused, for future expansion

int itk::image_dimension::glmax

This is the global max/min for the entire volume image (or sets of volume images if there are multiple volumes in this file). The cal_max/min are used only if the desired representation range of the data is different from the true range of the data. For example, CT data may be stored in signed shorts with a range from 0 - 2000, but an appropriate representation range for these values in in Hounsfield units from -1000 to 1000. Any reported values in Analyze were scaled via this value scaling function. UNSIGNED INT and COMPLEX were really not supported under ANALYZE 7.5., so these should be avoided in the Analyze 7.5 file format. The max/min for FLOATs was the nearest integer to the floating point values.

int itk::image_dimension::glmin

See also

image_dimension::glmax

float itk::image_dimension::pixdim[8]

Parallel array to dim giving voxel dimensions NOTE: pixdim[0] is ignored, and the number of dims are taken from dims[0], and pixdim[1..7] are the actual pixdims.

• pixdim[0] this field is not used
• pixdim[1] voxel width
• pixdim[2] voxel height
• pixdim[3] voxel depth or slice thickness
• pixdim[4]
• . . .
• pixdim[7]

float itk::image_dimension::roi_scale

The "ROI Scale Factor" was really added in by the developers of SPM. This is used as a multiplicative factor to scale all values measured in the ROI module by this multiplicative factor. This really shouldn't be set by any other application outside of Analyze and SPM.

short int itk::image_dimension::unused1

Unused field for future expansion.

int itk::image_dimension::verified

This was only used internally by Pre 1995 versions of analyze.

float itk::image_dimension::vox_offset

Byte offset in the .img file at which voxels start. If value is negative specifies that the absolute value is applied for every image in the file.

char itk::image_dimension::vox_units[4]

Specifies the spatial units of measure for a voxel, valid values are "mm","cm" and "in". NOTE: if no match is found, "mm" is assumed.

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The documentation for this struct was generated from the following file:

• itkAnalyzeDbh_p.h