how to draw lines using given points in a video?

First,I give some points to starting posistion of the video,I need to draw lines through that points and get angles using x,y values,

Currently i able add points and get x,y values of those points while video playing.

videoFileReader = vision.VideoFileReader('ex.mp4');
videoPlayer = vision.VideoPlayer('Position',[1,10,1280,720]);

 objectFrame = videoFileReader();
objectRegion = [264,122,93,93];

figure; 
imshow(objectFrame);
[shoulder_X,shoulder_Y]= ginput(1);
[elbow_x,elbow_y]= ginput(1);
[wrist_x,wrist_y]= ginput(1);
pos   = [shoulder_X,shoulder_Y;elbow_x,elbow_y;wrist_x,wrist_y];
color = {'red','green','magenta'};
start_x = shoulder_X;
start_y=shoulder_Y;
disp(shoulder_X +" - "+shoulder_Y);


% imshow(pointImage);
points = detectMinEigenFeatures(rgb2gray(objectFrame));
pointImage1 = insertMarker(objectFrame,pos,'+','Color',color,'size',10);
 plot([shoulder_X,shoulder_Y], [elbow_x,elbow_y]);
plot([wrist_x,wrist_y], [elbow_x,elbow_y]);
figure;
imshow(pointImage1);
title('Detected interest points');

tracker = vision.PointTracker('MaxBidirectionalError',1);
initialize(tracker,pos,objectFrame);
while ~isDone(videoFileReader)
      frame = videoFileReader();
      [points,validity] = tracker(frame);
      out = insertMarker(frame,points(validity, :),'+');
      videoPlayer(out);
      disp(points);
  
end

As shown in above image,

Black circle: current status of my code,and these points move when video playing,

Red Circle:I need to improve red circle to this level.and these lines should move when video playing.

I try to draw lines using plot function but its not work.

 plot([shoulder_X,shoulder_Y], [elbow_x,elbow_y]);
plot([wrist_x,wrist_y], [elbow_x,elbow_y]);

[darova]

try

plot([shoulder_X elbow_x wrist_x shoulder_X], ...
     [shoulder_Y elbow_y wrist_y shoulder_Y])

[vimal gayan]

not working :(

Answer 1

[Mark Sherstan]

Use insertShape(). Cool project!

[vimal gayan]

I tried with this and not able to work with the video.It's draw lines in images.Where should i insert this method in my code?

tracker = vision.PointTracker('MaxBidirectionalError',1);
initialize(tracker,pos,objectFrame);
while ~isDone(videoFileReader)
      frame = videoFileReader();
      [points,validity] = tracker(frame);
      out = insertMarker(frame,points(validity, :),'+');
      videoPlayer(out);
      disp(points);

And my video file is look like below.

      videoFileReader = vision.VideoFileReader('ex.mp4');
videoPlayer = vision.VideoPlayer('Position',[1,10,1280,720]);

and postion of points armention below:

[shoulder_X,shoulder_Y]= ginput(1);
[elbow_x,elbow_y]= ginput(1);
[wrist_x,wrist_y]= ginput(1);

using those code i can fill the parameters for insertShape();but where to put it to work while video playing.

[Mark Sherstan]

Right after you inser the marker is fine! Something like this (notice how i reassign out):

tracker = vision.PointTracker('MaxBidirectionalError',1);
initialize(tracker,pos,objectFrame);
while ~isDone(videoFileReader)
      frame = videoFileReader();
      [points,validity] = tracker(frame);
      out = insertMarker(frame,points(validity, :),'+');
      out = insertShape(out,'Line',position) % Where position is for one or more disconnected lines, an M-by-4 matrix, where each four-element vector [x1, y1, x2,y2], describe a line with endpoints, [x1 y1] and [x2 y2].
      videoPlayer(out);
      disp(points);

[vimal gayan]

it's work initialy,but it's not move when start the video.

tracker = vision.PointTracker('MaxBidirectionalError',1);
initialize(tracker,pos,objectFrame);
while ~isDone(videoFileReader)
      frame = videoFileReader();
      [points,validity] = tracker(frame);
      out = insertMarker(frame,points(validity, :),'+');
      out = insertShape(out,'Line',[shoulder_X shoulder_Y elbow_x elbow_y elbow_x elbow_y wrist_x wrist_y wrist_x wrist_y shoulder_X shoulder_Y] ); % Where position is for one or more disconnected lines, an M-by-4 matrix, where each four-element vector [x1, y1, x2,y2], describe a line with endpoints, [x1 y1] and [x2 y2].
      videoPlayer(out);
      disp(points);
  
end

Start Pos:

when video playing: Markers are move according to the video.but lines not

I think postions of insertshape() not updated while video playing.

In insertMarker() it works.

[Mark Sherstan]

You need to update the variables in the while loop. You are still calling their initial values.

[vimal gayan]

yep,Now i am trying to get that values from the variable 'points'

In below code i display those variable values(x,y) using 'points'

I need to get those values to array and access those values seperately,How can i extract values from that?

this line - > disp(points); show all the x,y values of the movement.I need to get those values to the array.How can i do that?inside thise while loop.

tracker = vision.PointTracker('MaxBidirectionalError',1);
initialize(tracker,pos,objectFrame);
points = detectMinEigenFeatures(rgb2gray(objectFrame));
while ~isDone(videoFileReader)
      frame = videoFileReader(); 
      [points,validity] = tracker(frame);
      out = insertMarker(frame,points(validity, :),'+','size',10);
      out = insertShape(out,'Line',[shoulder_X shoulder_Y elbow_x elbow_y elbow_x elbow_y wrist_x wrist_y wrist_x wrist_y shoulder_X shoulder_Y] ); % Where position is for one or more disconnected lines, an M-by-4 matrix, where each four-element vector [x1, y1, x2,y2], describe a line with endpoints, [x1 y1] and [x2 y2].
      videoPlayer(out);
      disp(points);
end

I tried to create array and put those values on to it,but it didnt work.

if I able to get those values seperately i will able add those values to 'InsertShape() method and move lines dynamically'

When i display the points inside the while loop, it show like this.

I need to get those values to array,How can i do that inside this while loop?

[Mark Sherstan]

This example should solve your question:

points = rand(3,2)
idx = 1;

for ii = 1:size(points,1)
    for jj = 1:size(points,2)
        array(idx) = points(ii,jj);
        idx = idx + 1;
    end
end

array

[vimal gayan]

Thanks for help,

I able to store the values in to array,

  ex_points{num_frame} = points;

then i try to print it using below code,

  disp(hist_points{5});

the result was loki below,

How can i get values seperately from this reslut??

I need result like each point x and y value seprately,In above image show 3 points at a one time.

[Mark Sherstan]

dpb answered your questions in a different post: https://www.mathworks.com/matlabcentral/answers/463710-how-to-extract-values-from-array#answer_376394

[vimal gayan]

got it,It works now as i want.Thanks for the continues help.

[vimal gayan]

https://www.mathworks.com/matlabcentral/answers/463909-how-to-show-given-x-y-position-on-image-frame

Hi,Do you know how to do this??