How to used the previous data if found ''Empty matrix:0-by-1"?

Iam already make a code to find the highest white pixels location through each row. Then,the problems is about it shows ''Empty matrix:0-b-1". Im trying to used if statement "isempy' then I want to read the prievious value before MATLAB found the isempty.

here is my code:

%point location
row=find(sum(BinaryImage,2)==0,1,'last')+1;
col=find(BinaryImage(row,:)~=0)
row=row(ones(size(col)));
if isempty(col)
    col = readpreviousData(col);
else
end

[Geoff Hayes]

nurul - where in your code is the previous non-empty column? Is there a for or while loop that you haven't included in the above code? Please include more code so that we can get an idea of how the previous column might be re-used here.

Answer 1

[Image Analyst]

Try this - it's untested but I think it should work

[rows, columns] = size(binaryImage);
topRows = zeros(1, columns);
lastRow = rows; % Initialize to bottom of image.
for col = 1 : columns
    t = find(binaryImage, 1, 'first'); % Find top row
    if ~isempty(t)
        topRows(col) = t; % Assign value from this column.
    else
        % Take last good value.
        topRows(col) = lastRow;
    end
    lastRow = topRows(col); % Update the last row
end

[nurul najmah]

i used the code but it marks on the lastrow and lastcolumn only. I want the mark on the highest white pixel of the row on the which column has the highest white pixel value of the row before.

    %point location
[row,column]=size(img8); %use the size of imdilate image
topRows=zeros(1,column); %Top row as black pixel
lastRow=row; %Initiate the bottom of img8
for col=1:column
    t=find(img8,1,'first');%find the topRow
    if ~isempty(t)
        topRows(col)=t;%assign value from this column
    else
        topRows(col)=lastRows;%take last good value
    end
    lastRows=topRows(col);%update the last row
end
Points=[row(:) col(:)];
imshow(img1);
hold on
plot(Points(:,2),Points(:,1)','rp','MarkerSize',12)
a=text(Points(1,2),Points(1,1),['This is (col,row)(',num2str(Points(1,2)),',',num2str(Points(1,1)),')']);
set(a, 'FontName', 'Arial' ,'FontWeight', 'bold', 'FontSize', 12,'Color', 'blue');
hold off

end

[nurul najmah]

here i put the information refer to the image. the problem when i used realtime,it shows 'Empty matrix 0-by-1' based on the col code.

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[Image Analyst]

Show me the error message. I see that you computed topRows, but I don't see you ever using it after that. Show me the error message that says that topRows is empty when you try to use it. And you'll need this link.