Why do I get this error of the '=' operator? I am trying to get the individual mean values of the blobs of pixels (in the image there are blobs of pixels and I want each mean)

Unsupported use of the '=' operator. To compare values for equality, use '=='. To pass name-value arguments using the name=value format, provide these arguments after all other inputs. Thank you SO much.

% Loads the z, 32 bit, single channel image 
rgbImage = imread('test1.jpg');
  
grayImage = double(rgbImage(:, :, 2));


%replace each pixel with the average of its 3x3 neighbors with 
%filtering with a radius of 2 pixels

mean3=conv2(grayImage,[0 1 0; 1 1 1; 0 1 0]/5,'same');
imshow(mean3, []);

%set a pixel threshold cutoff in imagej it was 60 - minimize background by choosing a 
%value cutoff, such that every pixel less than that value is considered one class, 
%while every pixel greater than that value is considered the other class.


roi = grayImage < 60; % Define roi by thresholding

%convert the intensity values of the background to "nothing" 
%rather than to 0 and keeps the other values


%divide this image by itself -> ROI

roifinal = roi./roi;
imshow(roifinal, []);

%Prompt user to load raw image

I = imread('raw.tif');
I = double(I);

%multiply ROI by the raw image

FinalRegOI = roi .* roi;

%Resulting region of Interest

imshow(FinalRegOI, []);

%inc the brightness of the image
I1 = I+50;
figure(1); imshow()

% Tabulate individual mean values 
info_table = table(meanOfPixelsInRoi = mean(grayImage(roi)), meanOfPixelsInRoi, 'VariableNames', {'FileName', 'Mean of pixel blobs'}); 
finalcount = sum(meanOfPixelsInRoi) 
disp(info_table)

[Star Strider]

I suggest instead:

filename = 'test1.jpg';

rgbImage = imread(filename);

. . .

meanOfPixelsInRoi = mean(grayImage(roi));

info_table = table(filename, meanOfPixelsInRoi, 'VariableNames', {'FileName', 'Mean of pixel blobs'});

or something similar.

I suspect that there may be other problems, so I am not posting this as an answer.

[Neo]

Thank you for your response.

By the way, why do you suggest to use filename?

This is the error I got:

Error using table
All table variables must have the same number of rows.

Error in benzaanalysis (line 32)
info_table = table(grayImage, meanOfPixelsInRoi, 'VariableNames', {'FileName', 'Mean of pixel blobs'});
 

Answer 1

[Walter Roberson]

info_table = table(meanOfPixelsInRoi = mean(grayImage(roi)), meanOfPixelsInRoi, 'VariableNames', {'FileName', 'Mean of pixel blobs'});

Until a couple of releases ago, that = in the middle of the table() call would have been strictly invalid syntax. I suspect that you are using one of those older versions.

In new enough versions, that call would be the equivalent of

table('meanOfPixelsInRoi',  mean(grayImage(roi)), meanOfPixelsInRoi, 'VariableNames', {'FileName', 'Mean of pixel blobs'})

except possibly the = form would be invalid because there are positional parameters afterwards.

You cannot use = in the middle of a call to assign to a temporary variable. MATLAB is not C or C++. In C and C++ the result of an = is the rvalue and can be used in an expression, but assignment is syntactic in MATLAB and cannot be used inside expressions.

[Neo]

Thank you for your response. This is the error I got:

Error using table
Wrong number of arguments.

Error in benzaanalysis (line 32)
table('meanOfPixelsInRoi',  mean(grayImage(roi)), meanOfPixelsInRoi, 'VariableNames', {'FileName', 'Mean of pixel blobs'})

Caused by:
    You might have intended to create a one-row table with the character vector 'meanOfPixelsInRoi' as one of its variables. To store text data in a table, use a string array or a
    cell array of character vectors rather than character arrays. Alternatively, create a cell array with one row, and convert that to a table using CELL2TABLE.

[Image Analyst]

You'd need to do

table(meanOfPixelsInRoi,  mean(grayImage(roi)), meanOfPixelsInRoi, ...
    'VariableNames', {'MeanOfPixelBlobs1', 'MeanOfPixelBlobs2', 'MeanOfPixelBlobs3'})

but why are you making a table wth only one row in it and all 3 columns the same??? Why not save them all up and make a table with the values from all your images.

[Neo]

How would I do that? @Image Analyst