[Octave-patch-tracker] [patch #8812] Added imquantize to image toolset

[anonymous]

URL:
  <http://savannah.gnu.org/patch/?8812>

                 Summary: Added imquantize to image toolset
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Fri 27 Nov 2015 11:14:48 PM UTC
                Category: None
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any

    _______________________________________________________

Details:

Attached is the diff patch,
following is the content of the m file submitted in the commit.
Please add it to the image toolset.

## Copyright (C) 2015 Motherboard
## 
## This program is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or
## (at your option) any later version.
## 
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
## 
## You should have received a copy of the GNU General Public License
## along with this program.  If not, see <http://www.gnu.org/licenses/>.

## -*- texinfo -*- 
## @deftypefn {Library Function} address@hidden = mat} imquant (@var{img}
mat, @var{levels} vector, @var{values} vector)
##  quant_A = imquantize(A,levels) quantizes image A using specified
quantization values contained in the N element vector levels. Output image
quant_A is the same size as A and contains N + 1 discrete integer values in
the range 1 to N + 1 which are determined by the following criteria:
##  If A(k) ≤ levels(1), then quant_A(k) = 1.
##  If levels(m-1) < A(k)  ≤  levels(m) , then quant_A(k) = m.
##  If A(k) > levels(N), then quant_A(k) = N + 1.
##  Note that imquantize assigns values to the two implicitly defined end
intervals:
##  A(k) ≤ levels(1)
##  A(k) > levels(N)
##  example
##  quant_A = imquantize(___,values) adds the N + 1 element vector values
where N = length(levels). Each of the N + 1 elements of values specify the
quantization value for one of the N + 1 discrete pixel values in quant_A.
##  If A(k) ≤ levels(1), then quant_A(k) = values(1).
##  If levels(m-1) < A(k)  ≤  levels(m) , then quant_A(k) = values(m).
##  If A(k) > levels(N), then quant_A(k) = values(N + 1).
##  example
##  [quant_A,index] = imquantize(___) returns an array index such that:
##  quant_A = values(index)
## @seealso{}
## @end deftypefn

## Author: Motherboard <address@hidden>
## Created: 2015-11-27

function [quantImg, index] = imquantize (img, levels, values)
  N = length(levels);
  if ~exist("values","var")
    values = 1:(N + 1); %if no values were given, set values to be labels.
    valuesPresent = false;
  elseif (length(values) ~= N + 1) %if values were given, make sure we have
exactly the right amount.
    error("values should have length of levels + 1")
  else
    valuesPresent = true; %if values were given, and everything is fine, we
might need to calculate the output index.
  endif
  quantImg = zeros(size(img));
  if isargout(2)          %if index is required, initialize it.
    index = quantImg;
  endif
  if (size(levels,1) == 1)  %check if levels is a column or a row vector to
concatinate it correctly with 0 on one side, and 256 on the other.
    levels = [0; levels; 256]; 
  elseif (size(levels,2) == 1)
    levels = [0 levels 256];
  else
    error("levels should be a vector")  %make sure levels is a vector
  endif
  for i = 1:(N+1)
    indicesToAssign = img >= levels(i) & img < levels(i+1);  %compute the
indices to be assign.
    quantImg(indicesToAssign) = values(i); 
    if (isargout(2) && valuesPresent)   %if index is required, and values were
given, assign labels to index.
      index(indicesToAssign) = i;
    endif
  end
  if (isargout(2) && ~valuesPresent) %if index is required, but values were
not given, index is identical to quantImg
    index = quantImg;
  endif  
endfunction



    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Fri 27 Nov 2015 11:14:48 PM UTC  Name: imquantize.diff  Size: 4kB   By:
None

<http://savannah.gnu.org/patch/download.php?file_id=35581>

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/patch/?8812>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/