READENVIROI - Read ENVI files.

Contents

Description

This function reads in an ENVI ROI file and outputs a Struct containing

ROI Name:         ROI.'ROI Number'.'Name'     (Char)
ROI Color:        ROI.'ROI Number'.'Color'    (vector)
ROI Num Points:   ROI.'ROI Number'.numPoints  (scalar)
ROI Data:         ROI.'ROI Number'.Points     (matrix)

Syntax

   ROI = READENVIROI(roiFile);

Output

ROI : the data in each cell of the struct is as outlined above. the matrix is of size # of bands plus the ID number, and (X,Y) coordinates by the number of points in the ROI.

Remark

Note that this function assumes a strict formatting standard for the ROI file. IT IS DESIGNED TO ONLY WORK ON THE ENVI ROI FILES SAVED IN ASCII FORMAT. The ROI points must follow immediately after the last ROI information line in the file top matter. There is a commented out while loop that was intended to test for the start of the ROI points, but was removed for convience. However, a more robust algorithm will test for the start of the ROI points so as to avoid strict formatting errors. Future improvements to this code may incorporate reading additional ROI file formats and/or the test for teh start of the roi points.

Acknowledgment

Written by Jared Herweg, Rochester Institute of Technology, May 2010 jxh6389@rit.edu

See also

Ressembles: READENVIRASTER.

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Function implementation

function ROI = readenviroi(roiFile)

open File

fid = fopen(roiFile);

get ROI header information

ROI = ''; % Initialize Struct
test = [];
while isempty(test)
    fline = fgetl(fid);
    % find number of ROIs
     test = find(strncmp('; Number of', fline, 11));
    % test = strmatch('; Number of',fline);
end
ROI.('NumROI') = str2double(strtrim(fline(strfind(fline,':')+1:end)));
test = [];

for each ROI, get associated info

for count = 1:ROI.NumROI
    while isempty(test)
        fline = fgetl(fid);
        test = find(strncmp('; ROI name', fline, 10));
       % test = strmatch('; ROI name',fline);
    end
    ROIName = strtrim(fline(strfind(fline,':')+1:end));
    fline = fgetl(fid);
    ROIcolor = str2double(strtrim(fline(strfind(fline,'{')+1:end-1)));
    fline = fgetl(fid);
    ROI_numPts = strtrim(fline(strfind(fline,':')+1:end));
    % Dynamically expand struct and assign ROI information to cell
    % fields
    ROIcnt = ['R' num2str(count)]; % Each independent ROI name assigned
    ROI.(ROIcnt).('Name') = ROIName;
    ROI.(ROIcnt).('Color') = ROIcolor;
    ROI.(ROIcnt).('numPts') = str2double(ROI_numPts);
    test = [];
end

get the ROI Points for each ROI

% Advance to the start of the ROI points
%     while isempty(test)
fline = fgetl(fid);
%         test = strmatch(';   ID',fline);
%     end

get number of bands in ROI

NumBands = length(find(fline == 'B'));

add 3 fields to num bands to account for ROI point ID and the x,y coordinates (see ROI ASCII file).

NumBands = NumBands + 3;

for each ROI, get the associative ROI points

for count = 1:ROI.NumROI
    ROIcnt = ['R' num2str(count)];
    ROI.(ROIcnt).('Points') = zeros(ROI.(ROIcnt).numPts,NumBands);
    for count2 = 1:ROI.(ROIcnt).numPts
        fline = fgetl(fid);
        ROI.(ROIcnt).Points(count2,:) = str2double(fline);
    end
    % fline = fgetl(fid); % skips the blank line
end

close ROI File

fclose(fid);

end % end of readenviroi