Seeing the image overlaid on image

I have this code with an image, and a diagonal line and a point plotted on the image. I want the point to move straight up and down whenever I press the space bar. When I run this code, I get two separate things - one with the image, line and dot, and one with the dot that moves up and down but on a blank background. What do I need to do to combine the two?

fs=100e3; % sampling frequency (Hz)
f=5000; % stimulus frequency (Hz)
dur = .0002; % duration (s)
ns = dur*fs; % # samples
t=(0:1:ns-1)/fs; % time vector (s)

a=1; % amplitude (arbitrary)xcsdg
phi=0; %phase (radians)

x=0; % x-position (fixed)

imshow('AvgBscan.tiff');
[rows, columns, numberOfColorChannels] = size('AvgBscan.tiff');
x = [0,150];
y = [0,100];
line(x,y, 'LineWidth', 4, 'Color', [1, 0, 1]);
plot(50,33,'yo', 'MarkerSize', 12)

for t_i = 1:length(t) % for each point in time
    y = a*sin(2*pi*f*t(t_i) + phi); % calculate y-position of circle according to the output of a sine wave at that time
    axis on
    hold on;
    h=figure;
    plot([-1 1],[0 0],'k--');
    xlim([-1 1]);
    ylim([-1 1]);
    pause; %close all;
end

[KSSV]

Read about hold on, set.

[SS]

Hi, I did that and changed some things but still no luck. Would appreciate if you could assist further.

fs=100e3; % sampling frequency (Hz)

f=5000; % stimulus frequency (Hz)

dur = .0002; % duration (s)

ns = dur*fs; % # samples

t=(0:1:ns-1)/fs; % time vector (s)

a=1; % amplitude (arbitrary)

phi=0; %phase (radians)

x=50; % x-position (fixed)

h = plot(50,33,'yo', 'MarkerSize', 12)'

for t_i = 1:length(t) % for each point in time

imshow('AvgBscan.tiff');

axis on;

hold on;

y = a*sin(2*pi*f*t(t_i) + phi)

% plot circle at x vs. y

set(h, 'YData', Y);

drawnow

plot([-1 1],[0 0],'k--');

xlim([0 100]);

ylim([0 80]);

pause; %close all;

end

Answer 1

[Madhav Thakker]

Hi,

You can use hold on for this purpose. You can change the pointer by changing the YData of the plot. I am attaching a code snippet for better understanding.

x = [-10,150];
y = [-10,150];
line(x,y, 'LineWidth', 4, 'Color', [1, 0, 1]);
hold on
pl = plot(0,0,'yo', 'MarkerSize', 12)
axis on
hold on
for t_i = 1:length(t) % for each point in time
    y = a*sin(2*pi*f*t(t_i) + phi) % calculate y-position of circle according to the output of a sine wave at that time
    hold on;
    axis on;
    pl.YData = y;
    hold on
    plot([-1 1],[0 0],'k--');
    xlim([-1 1]);
    ylim([-1 1]);
    pause; %close all;
end

Hope this helps.