Error: Expected input to be a vector

Hi folks,

I am calling a self-made function as follows:

ir = rotateAround(ig, Cy, Cx, Angle_DEG);

But the last variable, Angle_DEG, has no value so I get an error when calling this function. Angle_DEG is returned bu a different function as:

[Angle_DEG, LinePoint1, LinePoint2] = RotatedAngle(RawImages, files, xmin, ymin, CropH, CropW, a, i);

where rotatedAngle is returning all outputs without an actual numeric value...Any ideas why this might be please? The function is defined as follows:

function [ Angle_DEG, LinePoint1, LinePoint2] = RotatedAngle( RawImages, files, xmin, ymin, CropH, CropW, a, i )
%UNTITLED Summary of this function goes here
%   Detailed explanation goes here
%   Finding the angle for auto rotation of the image
%   Then recropping to remove the black edges due to rotation
  %% Finding the Image rotation based on the initial image %%
        file_name = files(i).name;
        im = imread([RawImages '\' file_name]);
        ig = rgb2gray(im(:,:,1:3));
        I = imcrop(ig,[xmin(i) ymin(i) CropW(a) CropH(a)]);       
%%% Using edge detection %%%        
        Bw = imbinarize(I, 24/255);
        IE = edge(Bw,'canny');
        %imshow(IE);
        %IE = edge(I,'canny',0.25);  %IE = edge(I,'canny',0.23)        
%% Getting data points for the tile %%    
    % (X1,Y1) Point on the left        
    X1 = round((size(IE,2))*1/10);
    X1line = IE(:,X1);    
    Y1s = find(X1line==1,500);            
    Y1s(Y1s == 0) = inf;
    LinePoint1 = max(Y1s,[],1);        
    % (X2,Y2) Point on the right
    X2 = round((size(IE,2))*9/10);
    X2line = IE(:,X2);    
    Y2s = find(X2line==1,500);
    Y2s(Y2s == 0) = inf;
    LinePoint2 = max(Y2s,[],1);
    %Y2Table(i) = Y2;
 %Angle between the line and the horizontal
     Coordinates = [X1,LinePoint1;X2,LinePoint2];
     Dist = pdist(Coordinates,'euclidean'); % not necessary     
     Angle_DEG = atan2(LinePoint2-LinePoint1,X2-X1)*180/pi;
end

Answer 1

[Max Heiken]

It seems to me Cy and Cx must be column vectors, that is how I could reproduce the error. The function can only handle scalars for Cy and Cx. If you need to rotate your image around many points, I suggest you do it in a loop instead.

[Teshan Rezel]

Hi @Max Heiken, I've checked but they are both scalars...not sure where else the error may lie!

[Max Heiken]

@Teshan Rezel

Would you mind enabling "pause on error" in the drop down menu below the run button, then run, then in the function call stack drop down menu select rotateAround, and double check the variables pointY and pointX? My only explanation would be that they unexpectedly change at some point in your program.

[Teshan Rezel]

@Max Heiken many thanks for this. It turns out my previous function call is outputting empty variables so my last variable input to the one I mentioned has no value, hence the error. I will update my question accordingly!

[Max Heiken]

@Teshan Rezel

I imagine that either X1line or X2line is all zeros, which causes find to return an empty array.

X1line = IE(:,X1);    
X1s = find(X1line==1,500);

[Teshan Rezel]

Hi @Max Heiken, it seems to be failing at the line

X1line = IE(:,X1);  

which is returning a column of zeros...throwing everything that follows off!

Do you know a way around this please? I'm not sure why its behaving like this.

[Max Heiken]

It is not possible to answer that without knowing the data or the goal.