Threshold

Interface of AimsThreshold command

Description

Not binary mode : output_image result preserves the levels of gray

Binary mode : output_image is binary (only black and white voxels)

Threshold : selection of one or two tresholds (case of between and outside)

Threshold + Not binary mode : selected voxels are in grey level and the others are black

Threshold + Binary mode : selected voxels are white and the others are black

Selection of threshold : a image is composed with grey levels from 0 to 4095 (for example image). The grey level '0' is in fact black color and the '4095' is white color, all others grey levels are between 1 and 4094. To know the minimun and the maximun of grey level, you can put your image in a browser in Anatomist and read tex_min (black) and tex_max (white) attributes. To handle grey levels of your image, use ROI module of Anatomist (option Connectivity Threshold).

Test image, tex_min = 0, tex_max = 4095

Mode	Description	Mode_no_binary : fasle	Mode_binary : true
less_than	to select all the voxels for which value of levels of gray is smaller than the threshold	Threshold1 = 350	Threshold1 = 350
less_or_equal	to select all the voxels for which value of levels of gray is smaller or equal to the threshold1	Threshold1 = 350	Threshold1 = 350
great_than	to select all the voxels for which value of levels of gray is larger than the threshold1	Threshold1 = 350	Threshold1 = 350
great_or_equal	to select all the voxels for which value of levels of gray is larger or equal to the threshold1	Threshold1 = 350	Threshold1 = 350
equal	to select all the voxels for which value of levels of gray is equal to the threshold	Threshold1 = 350	Threshold1 = 350
different	to select all the voxels for which value of levels of gray is different to the threshold	Threshold1 = 1800	Threshold1 = 1800
between	to select all the voxels for which value of levels of gray contained between 1 and 2	Threshold1 = 391 Threshold2 = 1078	Threshold1 = 391 Threshold2 = 1078
outside	select all voxels with a grey level outside threshold1 and threshold2	Threshold1 = 391 Threshold2 = 1078	Threshold1 = 391 Threshold2 = 1078

Parameters

image_input: 4D Volume ( input )

Mandatory
input data

image_output: 4D Volume ( output )

Mandatory
output data

mode: Choice ( input )

Mandatory : mode of threshold
lt : lower than
le : lower or equal to
gt : greater than
eq : equal to
di : differ
be : between
ou : outside

threshold1: Float ( input )

Mandatory
grey level 1

threshold2: Float ( optional, input )

Optional except for between and outside modes:
grey level 2

binary: Boolean ( optional, input )

Optional
return a short binary data

Technical information

Toolbox : Tools

User level : 1

Identifier : threshold

File name : brainvisa/toolboxes/tools/processes/threshold.py

Supported file formats :

image_input :

GIS image, Z compressed GIS image, gz compressed GIS image, VIDA image, NIFTI-1 image, gz compressed ECAT i image, MINC image, gz compressed MINC image, DICOM image, TIFF image, XBM image, PBM image, PGM image, BMP image, XPM image, PPM image, gz compressed NIFTI-1 image, TIFF(.tif) image, gz compressed VIDA image, Z compressed VIDA image, Z compressed ECAT i image, gz compressed ECAT v image, ECAT i image, Z compressed ECAT v image, PNG image, JPEG image, MNG image, GIF image, Z compressed SPM image, SPM image, gz compressed SPM image, ECAT v image

image_output :

GIS image, VIDA image, NIFTI-1 image, MINC image, TIFF image, XBM image, PBM image, PGM image, BMP image, XPM image, PPM image, gz compressed NIFTI-1 image, ECAT i image, PNG image, JPEG image, MNG image, GIF image, SPM image, ECAT v image