Display plot on image

Hi, i want to display a plot of scanning track on the original image but the axes values of the image are different from the values of the plot graph (the image i got is attached, the plot is appears in RED color at the top left of the image and the dimensions of the plot is much smaller than the dimensions of the image). How can I make sync between the axes system of the image and the plot scanning track?

Thanks, Itai

Answer 1

[Image Analyst]

Nothing is attached. You'd have to display your image and then set hold on and then plot your (x,y) data with x and y scaled to the number of pixels in each direction. Then you'd have to set the YDir property to 'reverse', or else flip your image vertically with flipud() before you call imshow().

[Itai Kadosh]

Hi, Sorry...now i have attached 3 files the original image, the scanning mask and the display of them on one image.

Itai

[Image Analyst]

I see a plot and two binary images. I'm not seeing "the display of them on one image" <== which image is that? What's the difference between the two binary images. How did you get the (x,y) data in the range of [-4, +4]? Evidently it did not come from the rows or columns of the image because your image is a lot bigger than 8 pixel tall.

[Itai Kadosh]

Hi,

The "original image" is the original image, the "scanning mask" is the track i need to scan and in the "scanning track" there is the presentation of both (the scanning mask image appears in the left corner as a small graph in red color). The code is attached and I want to display Figure 6 ("scanning mask" image) on Figure 5 ("original image") in the same image so Figure 6 will appears in the "white"part of Figure 5.

The X and Y axes in Figure 6, expresses Volts in X Vs. Volts in Y (there are 2 mirrors that perform the scanning).

Thank you very much!

Answer 2

[Thorsten]

x = cumsum(Volt_and_time(2,:));
y = cumsum(Volt_and_time(1,:));
overlayplot(x,y,image, 'fitbinary')

using my function overlayplot:

function h = overlayplot(x, y, I, rect)
%OVERLAYPLOT Plot an overlay of function x,y on the image I.
%
%   H = OVERLAYPLOT(X, Y, I, [RECT])
%
% Plots that do not keep the aspect ratio of the plot:
% OVERLAYPLOT(X, Y, I) Plot function scaled to the size of the image I.
% OVERLAYPLOT(X, Y, I, RECT) Plot function scaled to rectangle. Rectangle
%   is given by its coordinates [XMIN XMAX YMIN YMAX].
%
% Function scaled to the size of the image, keeping the aspect ratio of the 
% plot:
% OVERLAYPLOT(X, Y, I, []) Plot function witout offset.
% OVERLAYPLOT(X, Y, I, DXY) Plot function with an offset in X and Y 
%   direction given by DXY = [DX DY].
% OVERLAYPLOT(X, Y, I, OPTION), with OPTION = 'center' or 'c'. Plot 
%   centered on the image.
% OVERLAYPLOT(X, Y, I, OPTION), with OPTION = 'fitbinary' or 'ft'. Plot 
%   fitted to the white area of the binary image I.
%
%   [e-mail]  2016-01-19

%%Process arguments
switch nargin
  case 3
    plotoption = 1;
  case 4
    if ischar(rect) 
      if strcmp(rect, 'center') || strcmp(rect, 'c')
        plotoption = 33; % keep ratio, center
      elseif strcmp(rect, 'fitbinary') || strcmp(rect, 'fb')
        % fit to rectangle given by white area of binary image
        if ~islogical(I)
          error('Image must be of class logical for option fitbinary.')
        end
        rect = [find(diff(sum(I)>0)~= 0) find(diff(sum(I,2)'>0)~= 0)];
        rect = rect + [1 0 1 0]; % correct off by one error
        plotoption = 2; 
      else
        error('String must be ''center'', ''c'', ''fitbinary'' or ''fb''.')
      end
    else
      switch numel(rect)
        case 0
          plotoption = 31; % keep ratio, no offset
        case 2
          plotoption = 32; % keep ratio, offset dx, dy given in rect
        case 4
          plotoption = 2; % scale to fit given rectangle
        otherwise
          error('Wrong number of elements, must be 0, 2 or 4.')
      end
    end
  otherwise
    errro('Wrong number of arguments, must be 3 or 4.')
end

%%Determine scale factors and offset

% first scale xy to [0,1]
wxy = max(x) - min(x); hxy = max(y) - min(y);
x0 = (x - min(x))/wxy;
y0 = (y - min(y))/hxy;

wI = size(I,2); hI= size(I,1); % width and height of image
switch plotoption
  case 1 % scale plot to full size of image, ignoring ratio of plot
    sx = wI; sy = hI;
    dx = 0; dy = 0; % no offset

    case 2 % scale plot to fit rectangle rectxy
      % rectangle given by [xmin, xmax, ymin, ymax]
      xmin = rect(1); xmax = rect(2); ymin = rect(3); ymax = rect(4);
      sx = xmax - xmin; sy = ymax - ymin;
      dx = xmin;
      dy = ymin;

    case {31, 32, 33} % scale plot, keeping ratio 
      % determine ratio of image and plot and scale accordingly
      rI = wI/hI; % width/height
      rxy = wxy/hxy;
      if rI > rxy
        s = hI; 
      else
        s = wI;
      end
      sx = s; sy = s;
      % determine offset
      switch plotoption
        case 31 % empty rect
          dx = 0; dy = 0; % default is no offset
        case 32 % offset in x and y
          dx = rect(1); dy = rect(2);
        case 33 % center      
          dx = (wI-sy)/2;
          dy = (hI-sx)/2;
        otherwise
          error('Internal error: plotoption can be only 31, 32, or 33.')
      end   

    otherwise
      error('Internal error, plotoption can only be 1, 2 or 3.');    
  end

%%Show overlay 
imshow(I)
hold on
h = plot(sx*x0+dx, sy*y0+dy);

if nargout == 0, clear h, end