how to fix "unrecognized table variable name" error?

hi. i'm running a matlab code that extracts images and forms corresponding bounding boxes, but i get the following error:

"Error using trainextract (line 7)

Unrecognized table variable name 'imds'."

the code is as follows:

clear all
close all
clc
imds = imageDatastore('C:\Users\Muhammad Sanwal\Desktop\COMSATS\The 9th Semester (FA20)\FYP pt 1\MIO-TCD-Localization\train\00000000.jpg');
%%To import data from a CSV file into MATLAB use the “readtable” function. The “readtable” function automatically detects the header and the number of lines to skip
T = readtable('C:\Users\Muhammad Sanwal\Desktop\COMSATS\The 9th Semester (FA20)\FYP pt 1\MIO-TCD-Localization\test1.csv','ReadVariableNames',false);
getdata = T.imds;

the image under test is:

can someone please help me fix this error?

note: if someone will edit this code, he/she would have to write his own location where the image is stored.

the csv file is attached as well.

Answer 1

[Walter Roberson]

imds = imageDatastore('C:\Users\Muhammad Sanwal\Desktop\COMSATS\The 9th Semester (FA20)\FYP pt 1\MIO-TCD-Localization\train\00000000.jpg');
%%To import data from a CSV file into MATLAB use the “readtable” function. The “readtable” function automatically detects the header and the number of lines to skip
T = readtable('C:\Users\Muhammad Sanwal\Desktop\COMSATS\The 9th Semester (FA20)\FYP pt 1\MIO-TCD-Localization\test1.csv','ReadVariableNames',false);
[imgfound, imgidx] = ismember(T.Var1, imds.Files);
T.img = cell(height(T),1);
for K = 1 : length(imgfound)
    if imgfound(K)
        T.img{K} = readimage(imds, imgidx(K));
    else
        T.img{K} = zeros(0, 0, 3, 'uint8');
    end
end

Any image listed in the csv and is present in the imds under the exact same name will have its T.img entry set to the content of the image; any file not located in the imds will have T.img set to an empty RGB image.

[Muhammad Sanwal]

it gives the following error:

Error using cell/ismember (line 34)

Input A of class double and input B of class cell must be cell arrays of character vectors, unless one is a character

vector.

Error in trainextract (line 4)

[imgfound, imgidx] = ismember(T.Var1, imds.Files);

[Walter Roberson]

T = readtable('test1.csv', 'readvariablenames', false)

T = 1x6 table
                                                            Var1                                                                                    Var2                                   Var3                Var4          Var5               Var6        
    _____________________________________________________________________________________________________________________    __________________________________________________    _____________________    __________    __________    ____________________

    {'C:\Users\Muhammad Sanwal\Desktop\COMSATS\The 9th Semester (FA20)\FYP pt 1\MIO-TCD-Localization\train\00000000.jpg'}    {'"[194,78,273,122;155,27,183,35;106,32,124,45]"'}    {'"[213,34,255,50]"'}    {0×0 char}    {0×0 char}    {'"[43,25,109,55]"'}

T.Var1

ans = 1x1 cell array
    {'C:\Users\Muhammad Sanwal\Desktop\COMSATS\The 9th Semester (FA20)\FYP pt 1\MIO-TCD-Localization\train\00000000.jpg'}

It does not come out as double as your error message indicates.

Answer 2

[Jeremy Hughes]

'ReadVariableNames',false

This tells readtable not to read variable names from the file. So all the variable names will be "Var1","Var2",..., etc.

T.imds is trying to acces the variable named "imds" which doesn't exist.

[Muhammad Sanwal]

Even if i remove 'ReadVariableNames',false, when i run the code, the following warning appears along with the same error mentioned above:

"Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property. Set 'PreserveVariableNames' to true to use the original column headers as table variable names."

[Jeremy Hughes]

Yes, because "imds" is not a variable name in the table T.

It's hard to say what you need to do next, because it's not clear what data you're trying to get out of that table.

If you want to read the data in the image, you should be calling,

read(imds)

[Jeremy Hughes]

You might also want to scan https://www.mathworks.com/help/matlab/tables.html