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im_threshold

IM_THRESHOLD

Fixed mapping thresholding images (DIP_Image)

B = IM_THRESHOLD(A,TYPE,PAR,INV)
B = A*IM_THRESHOLD([],TYPE,PAR,INV)
B = A*IM_THRESHOLD(TYPE,PAR,INV)

 Input A Dataset with object images (possibly multi-band) TYPE Type of procedure, see below PAR Related parameter INV If INV = 1, result inverted, default INV = 0.

 Output B Dataset with thresholded images

Description

The following procedures are supported (TYPE)

 'isodata': Thresholding using the Isodata algorithm 'otsu': See IM2BW 'triangle': *Thresholding using chord method  (a.k.a. skewed bi-modality, maximum distance to triangle)  by Zack, Rogers and Latt (1973). 'background': *Thresholding using unimodal background-symmetry method. 'fixed': Thresholding at a fixed value. 'double': *Thresholding between two fixed values. 'volume': *Thresholding to obtain a given volume fraction. 'hysteresis': *From the binary image (in>low) only those regions are  selected for which at least one pixel is (in>high)

The following parameters are related to these procedures (PAR)
('background'): Distance to the peak where we cut-off, in  terms of the half-width at half the maximum.  Inf selects the default value, which is 2.

 ('fixed'): Threshold value. Inf means halfway between  minimum and maximum value. ('double'): Two threshold values. Inf means min+[1/3,2/3]*(max-min). ('volume'): Parameter = the volume fraction (Inf means 0.5) ('hysteresis'): Two values: low, high (see above)

* routine needs DIP_IMAGE

This routine is for smart thresholding. Simple thresholding can also be  performed by B = A > PAR, which is the same as using the type 'fixed'.