Dot indexing is not supported for variables of this type.

I faced this problem here. Please help me. I already try with give solution .

 image_files = [];
    for f = isfolder(image_path)
        if f.endsWith([".jpg",".jpeg",".png", ".PNG"])  //problem is here
            image_files.append(f);
        end
    end

Problem

Dot indexing is not supported for variables of this type.

Error in undistortion>undistorb_images (line 51)

if f.endsWith([".jpg",".jpeg",".png", ".PNG"])

[DGM]

You're going to have to explain what exactly you're trying to do here, because this code doesn't make any sense.

% what is image_path? is it a scalar string or char vector?
% is it a string array or a cell array of chars?
image_path = ???;
image_files = [];

% assuming image_path specifies multiple files, 
% isfolder() will output a logical vector.
% f will be scalar logical, and the loop steps through each value
% but they're never used for anything
% if you're intending to only look at paths which are directories
% then why is the inner conditional looking to see if they're image files?
for f = isfolder(image_path)
    % f is a scalar logical.  it has no method endsWith().
    % the correct syntax endsWith(f,pattern) doesn't make sense either
    % because f is a scalar logical, not a string or char.
    if f.endsWith([".jpg",".jpeg",".png", ".PNG"])  //problem is here
        % again, append() doesn't work like that, and it doesn't work
        % on logical scalars either.  even if it did, this entire loop
        % would accomplish nothing but disassembling the output from 
        % isfolder() and then reassembling it back into a logical vector.
        image_files.append(f);
    end
end

Are you trying to recursively search directories and build a list of paths to image files? What about image files that are not in a directory, but are specified directly in image_path?

[Md Shahidul Islam]

Yes, I am trying to recursively search directories and build a list of paths to image files. Here is my full code:

undistorb_images([], []);
function [tvec, rvec, camera_matrix, dist] = read_wp2c(input_name)
    %input_name = "output_wp2camera.json";
    raw = fileread(input_name); 
    input_params = jsondecode(raw);

    camera_matrix = input_params.camera_matrix;
    dist = input_params.dist_coefs;
    tvec_json = input_params.translational_vectors;
    %tvec = struct2cell(tvec_json);
    rvec_json = input_params.rotational_vectors;
    %rvec = struct2cell(rvec_json);

    tvec  = [];
    rvec = [];
    len = length(tvec_json);
    for i = 1:len
        %tvec.append(array(tvec_json(image + string(i))))
        %tvec.append.tvec_json(i);
        tvec = struct2cell(tvec_json(i));
        %[A{:}]
        %tvec.append(input_params.translational_vectors.image0);
        %rvec.append(array(rvec_json(image + string(i))));
        rvec = struct2cell(rvec_json(i));
    end


end


function undistorb_images(inputParams, result)
    %if result is None:
    if isempty(result)
        input_name = "output_wp2camera.json";
        [tvec, rvec, camera_matrix, dist] = read_wp2c(input_name);
    else 
        tvec = result(4);
        rvec = result(3);
        camera_matrix = result(1);
        dist = result(2);
    end
    if isempty(inputParams)
        image_path = "D:\matlab_code\Calibration_Task\images\";
    else
        image_path = inputParams.opencv_storage.settings.Images_Folder;
    end

    
    
    image_files = [];
    files = [dir(fullfile(image_path,'*.jpg')); dir(fullfile(image_path,'*.png')); dir(fullfile(image_path,'*.jpeg')); dir(fullfile(image_path,'*.PNG'))];
    %files = dir(fullfile(image_path, '*.(jpg|png)'));
    L = length(files);
    for i=1:L
        image_files=files(i).name;
        %disp(file)
    end
    
  
    
%     for f = dir(image_path)
%         %ext = image_path(split(lower(f)));
%         %disp(f)
%         %if f.endsWith([".jpg",".jpeg",".png", ".PNG"])
%          %   image_files.append(f);
%         %end
%     end
    image_file_name = [];
    if ~isempty(image_files)
        for image_file = image_files
            image_file_name.append(image_file);
            image = imread(image_path + "/" + image_file);
            [height, width] = size(image);
            print(str(height) + " " + str(width))
            [newcameramtx, roi] = getOptimalNewCameraMatrix(camera_matrix, dist, [width,height], 0, [width,height]);
            % dst = cv2.undistort(image, camera_matrix, dist, None, newcameramtx)
            [mapx, mapy] = cv.initUndistortRectifyMap(camera_matrix, dist, None, newcameramtx, [width,height], 5);
            dst = cv.remap(image, mapx, mapy, INTER_LINEAR);
            x, y, w, h = roi;
            dst = dst(y:y+h, x:x+w);
            [height, width] = size(dst);
            print(str(height) + " " + str(width));
            imwrite("undistortion/" + image_file, dst);
        end
    end
end

Answer 1

[Adam Danz]

> I am trying to recursively search directories and build a list of paths to image files

Inputs:

% Define the main directory
image_path = 'C:\Users\name\Documents';  

% list accepted extensions (with leading dot, case ignored)
acceptedExt = [".jpg",".jpeg",".png"]; 

Recursively search main directory (and sub directories) for files with listed extensions. fileList contains a cell array of full paths to matched files. The extension match ignores case.

d = dir(fullfile(image_path,'**\*.*')); 
d([d.isdir]) = [];  % remove directories from list
[~,ext] = regexp({d.name}','.*(\..*$)','match','once','tokens');
isAccepted = ismember(lower([ext{:}]), lower(acceptedExt)); 
d(~isAccepted) = []; % remove files that do not have accepted ext.

% list full paths to accepted files
fileList = fullfile({d.folder},{d.name})';

[Md Shahidul Islam]

Thank you so much for time and support.

[Adam Danz]

Sure, to display the number of accepted files for each extension, replace the ismember line with the line below and add the second block of code to the end.

[isAccepted,extIdx] = ismember(lower([ext{:}]), lower(acceptedExt)); 

% Count number of matches for each acceptedExt
unqExtIdx = unique(extIdx(isAccepted));
count = histcounts(extIdx(isAccepted), 'BinMethod','integers');
disp(compose('%s: %.0f', acceptedExt', count'))

Example output:

ans =

4×1 cell array

{'.jpg: 388'}

{'.jpeg: 0' }

{'.png: 0' }

{'.gif: 1' }