Index in position 1 is invalid. Array indices must be positive integers or logical values.

Hi.

close all;
clear variables;
%Files and Pics
data_list = dir('*.bmp');
%Zugreifen auf Ordner und BIlder und Namen zuweisen
name = {data_list.name};
%Konvertieren in Matrix
imBlack = imread("460_dunkel.bmp");
name(strcmp(name,"460_dunkel.bmp")) = []; % remove 460_dunkel.bmp
lambda = 0.633; %Wellenlänge Laser in um
Pixelgroesse = 4.65; %Pixelgroesse in um
for i = 1:length(name)
    picture = imread(name{i});  %Einlesen des Bildes in Matrix
    current_name = name{i};
    zaxe = str2double(name{i}(1:3)); %Auslesen des z Wertes aus Dateinamen
    
    imBlack = double(imBlack);
    pictures(:,:,i)=picture;    %speichert das aktuelle (i-te) 
    %Bild als 2D Matrix in der 3D Matrix (:,:,i)
    picture = double(picture);
    filtered = double(minus(picture,imBlack));
    
    %Ermittlung ROI
    ROI = im2double(filtered);
    ROIdiff = [1,1];
    ROIoffset =[0, 0];
    
    en_density = sum(sum((ROI)));
    [row,column] = size(ROI);
    xv = (1:column);
    yv = (1:row).';
    
    first_Moment_X(i,1) = sum(xv .* ROI, 'all');
    Schwerp_X           = first_Moment_X(i) / en_density;
    Schwerpunkte_X(i)   = Schwerp_X;
    
    first_Moment_Y(i,1) = sum(yv .* ROI, 'all');
    Schwerp_Y           = first_Moment_Y(i) / en_density;
    Schwerpunkte_Y(i)   = Schwerp_Y;
    
    sec_Moment_X(i,1) = sum((xv - Schwerp_X).^2 .* ROI, 'all');
    Sigma_X_plural(i) = sec_Moment_X(i)/en_density;
    sec_Moment_Y(i,1) = sum((yv - Schwerp_Y).^2 .* ROI, 'all');
    Sigma_Y_plural(i) = sec_Moment_Y(i) / en_density;
    sec_Moment_XY(i,1) = sum((xv - Schwerp_X) .* (yv - Schwerp_Y) .* ROI, 'all');
    Sigma_XY_plural(i) = sec_Moment_XY(i) / en_density;
    %Berechnung des Strahldurchmessers nach Formel 18 und 19 in Norm 
    dxPixel(i) = 2*sqrt(2)*(sqrt(Sigma_X_plural(i) + Sigma_Y_plural(i)+sign(Sigma_X_plural(i)-Sigma_Y_plural(i)).*(sqrt(((Sigma_X_plural(i)-Sigma_Y_plural(i)).^2)+4*(Sigma_XY_plural(i).^2)))));
    dyPixel(i) = 2*sqrt(2)*(sqrt(Sigma_X_plural(i) + Sigma_Y_plural(i)-sign(Sigma_X_plural(i)-Sigma_Y_plural(i)).*(sqrt(((Sigma_X_plural(i)-Sigma_Y_plural(i)).^2)+4*(Sigma_XY_plural(i).^2)))));
    dx(i,1) = dxPixel(i) * Pixelgroesse;   %Umrechnung von Pixel in Mikrometer
    dy(i,1) = dyPixel(i) * Pixelgroesse;   %Umrechnung von Pixel in Mikrometer
    dz(i,1) = zaxe; %Nur um alles am selben Fleck zu haben
    %{   
    imagesc(picture);
    axis on
    hold on;
    plot(ROIoffset(2)+Schwerpunkte_X, ROIoffset(1)+Schwerpunkte_Y,'r+', 'MarkerSize', 5, 'LineWidth', 1);
    t=-pi:0.01:pi;
    dx=ROIoffset(2)+Schwerpunkte_X(i)+dxPixel(i)*0.5*cos(t);
    dy=ROIoffset(1)+Schwerpunkte_Y(i)+dyPixel(i)*0.5*sin(t);
    plot(dx,dy,'g')
    hold off
    %} 
    
end
for j = 1 : length(name)
    delta_x(j) = dx(i) * 1.5;
    delta_y(j) = dy(i) * 1.5;
    
    new_roi = filtered(Schwerpunkte_X(i) - delta_x(j) : Schwerpunkte_X(i) + delta_x(j), Schwerpunkte_Y(i) - delta_y(j) : Schwerpunkte_Y(i) + delta_y(j));
    structROI(i).ROI= new_roi;
    new_ROIdiff = [1,1];
    new_ROIoffset =[0, 0];
    en_density = sum(sum((new_roi)));
    [row,column] = size(new_roi);
    xv = (1:column);
    yv = (1:row).';
    
    first_Moment_X(j,1) = sum(xv .* new_roi, 'all');
    Schwerp_X           = first_Moment_X(j) / en_density;
    Schwerpunkte_X(j)   = Schwerp_X;
    
    first_Moment_Y(j,1) = sum(yv .* new_roi, 'all');
    Schwerp_Y           = first_Moment_Y(j) / en_density;
    Schwerpunkte_Y(j)   = Schwerp_Y;
    
    sec_Moment_X(j,1) = sum((xv - Schwerp_X).^2 .* new_roi, 'all');
    Sigma_X_plural(j) = sec_Moment_X(j)/en_density;
    sec_Moment_Y(j,1) = sum((yv - Schwerp_Y).^2 .* new_roi, 'all');
    Sigma_Y_plural(j) = sec_Moment_Y(j) / en_density;
    sec_Moment_XY(j,1) = sum((xv - Schwerp_X) .* (yv - Schwerp_Y) .* new_roi, 'all');
    Sigma_XY_plural(j) = sec_Moment_XY(j) / en_density;
    %Berechnung des Strahldurchmessers nach Formel 18 und 19 in Norm 
    dxPixel(j) = 2*sqrt(2)*(sqrt(Sigma_X_plural(j) + Sigma_Y_plural(j)+sign(Sigma_X_plural(j)-Sigma_Y_plural(j)).*(sqrt(((Sigma_X_plural(j)-Sigma_Y_plural(j)).^2)+4*(Sigma_XY_plural(j).^2)))));
    dyPixel(j) = 2*sqrt(2)*(sqrt(Sigma_X_plural(j) + Sigma_Y_plural(j)-sign(Sigma_X_plural(j)-Sigma_Y_plural(j)).*(sqrt(((Sigma_X_plural(j)-Sigma_Y_plural(j)).^2)+4*(Sigma_XY_plural(j).^2)))));
    dx(j,1) = dxPixel(j) * Pixelgroesse;   %Umrechnung von Pixel in Mikrometer
    dy(j,1) = dyPixel(j) * Pixelgroesse;   %Umrechnung von Pixel in Mikrometer
    dz(j,1) = zaxe; %Nur um alles am selben Fleck zu haben
end

the code above gibes me the mistake message:

Warning: Integer operands are required for colon operator when used as index.

> In Laser_V2_Bersin_Sven (line 85)

Index in position 1 is invalid. Array indices must be positive integers or logical values.

Error in Laser_V2_Bersin_Sven (line 85)

new_roi = filtered(Schwerpunkte_X(i) - delta_x(j) : Schwerpunkte_X(i) + delta_x(j), Schwerpunkte_Y(i) - delta_y(j) : Schwerpunkte_Y(i) + delta_y(j));

can anyone help me please?

[Torsten]

What do you want to extract from "filtered" using the command

new_roi = filtered(Schwerpunkte_X(i) - delta_x(j) : Schwerpunkte_X(i) + delta_x(j), Schwerpunkte_Y(i) - delta_y(j) : Schwerpunkte_Y(i) + delta_y(j));

[the cyclist]

Is this question different from this one you asked an hour ago?

[Bersin Tekmen]

@Torsten The elliptical part, I calculated before. It is the diameter of a laser point. In some cases it is calculated inaccurately so I want to use the calculated diameter as the new region of interest (roi) to start a second and more accurate calculation.

Answer 1

[dpb]

In

new_roi = filtered(Schwerpunkte_X(i) - delta_x(j) : Schwerpunkte_X(i) + delta_x(j),  ...
                   Schwerpunkte_Y(i) - delta_y(j) : Schwerpunkte_Y(i) + delta_y(j));

you're trying to use the expression with colon operator as a subscripting expression into the array filtered but you've defined

    delta_x(j) = dx(i) * 1.5;
    delta_y(j) = dy(i) * 1.5;

above as fractional values. There is no such thing as addressing an array element with a non-integer expression that this will evaluate to. It's the same as if you had written

new_roi=filtered(3.5:8.5);

which obviously is a syntax error.

Either define your delta variables as integral steps or use some form of rounding(*) in the locations in which you subsequently use them as indices.

(*) floor(), ceil(), round() depending on your desires -- have to ensure stay in range of the array, of course.

[Bersin Tekmen]

thank you for your help.

[dpb]

Glad to help...

If that solved the issue, go ahead and Accept Answer to let others know if nothing else...

Answer 2

[Image Analyst]

There is a thorough discussion in the FAQ:

Subscript indices must either be real positive integers or logicals

Read it. The following link will also be useful:

Debugging in MATLAB | Doug's MATLAB Video Tutorials

[Bersin Tekmen]

Thank you for the debugging video. Helped me alot