Matlab GUI not showing line plot graph data - matlab

Question

I'm working with my Matlab GUI file to play video and plot the mean value from the color channel (RGB). It has 2 axes, the first one for the video player and second axis for the mean graph, but the second axis is not showing any data, it just updates the x and y coordinate but not showing anything.
I've tried to change the handles, changes the next plot setting in the property inspector but it doesn't work
function main_OpeningFcn(hObject, eventdata, handles, varargin)
handles.output = hObject;
video = vision.VideoFileReader();
handles.video = video;
frameCount = 0;
handles.frameCount = frameCount;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes main wait for user response (see UIRESUME)
uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = main_OutputFcn(hObject, eventdata, handles)
% varargout cell array for returning output args (see VARARGOUT);
% hObject handle to figure
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Get default command line output from handles structure
handles.output = hObject;
varargout{1} = handles.output;
% --- Executes on button press in Browse.
function Browse_Callback(hObject, eventdata, handles)
% hObject handle to Browse (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
[ video_file_name,video_file_path ] = uigetfile({'*.avi'},'Pick a video file'); %;*.png;*.yuv;*.bmp;*.tif'},'Pick a file');
if(video_file_path == 0)
return;
end
input_video_file = [video_file_path,video_file_name];
fullpath = strcat(video_file_path,video_file_name);
set(handles.edit1,'String',fullpath);
video = vision.VideoFileReader(input_video_file);
vidFrame = step(video);
axes(handles.axes1);set(handles.StartButton,'String','Start');
frameCount = 1;
imshow(vidFrame);
drawnow;
axis(handles.axes1,'off');
for nChannel = 1:3
colorChannel = vidFrame(:,:,nChannel);
rawColorSignal(nChannel,frameCount) = mean(mean(colorChannel));
end
%plot(frameCount,rawColorSignal(1, :),frameCount,rawColorSignal(2, :),frameCount,rawColorSignal(3, :), handles.axes2);
axes(handles.axes2)
plot(frameCount,rawColorSignal(1, :));
grid on
drawnow;
axes(handles.axes1)
% Display Frame Number
%Update handles
handles.video = video;
guidata(hObject,handles);
% --- Executes on button press in StartButton.
function StartButton_Callback(hObject, eventdata, handles)
% hObject handle to StartButton (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
if strcmp(get(handles.StartButton,'String'),'Pause')
set(handles.StartButton,'String','Start');
else
set(handles.StartButton,'String','Pause');
end
video = handles.video;
if isDone(video)
reset(video)
frameCount = 0;
handles.frameCount = frameCount;
end
frameCount = handles.frameCount;
while ~isDone(video) && strcmp(get(handles.StartButton,'String'),'Pause')
vidFrame = step(video);
imshow(vidFrame,'Parent',handles.axes1); %plot frame is specific axis
drawnow;
frameCount = frameCount + 1;
for nChannel = 1:3
colorChannel = vidFrame(:,:,nChannel);
rawColorSignal(nChannel,frameCount) = mean(mean(colorChannel));
end
plot(frameCount,rawColorSignal(1, :),'Parent',handles.axes2);
grid on
drawnow;
end
%plot(frameCount,rawColorSignal(1, :),'r',frameCount,rawColorSignal(2, :),'g',frameCount,rawColorSignal(3, :),'b','Parent', handles.axes2);
%drawnow;
set(handles.StartButton,'String','Start');
% --- Executes on button press in PauseButton.
function PauseButton_Callback(hObject, eventdata, handles)
% hObject handle to PauseButton (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
%axes(handles.axes2)
%surf(membrane(3))
What I expected is the line plot is visible and updating alongside the axes.

Answer 1

I think I found the problem:
Replace: plot(frameCount,rawColorSignal(1, :));
With: plot(1:frameCount,rawColorSignal(1, :));
Replace: plot(frameCount,rawColorSignal(1, :),'Parent',handles.axes2);
With: plot(1:frameCount,rawColorSignal(1, :),'Parent',handles.axes2);
plot(frameCount,... uses the scalar frameCount as X coordinates.
You want the X coordinates in your plot to be a vector that goes from 1 to frameCount.
In case you are getting an error, try:
plot(1:length(rawColorSignal(1, :)), rawColorSignal(1, :), 'Parent', handles.axes2);
I created the following sample code for demonstrating the problem:
Following sample is not plotting:
frameCount = 0;
rawColorSignal = [];
for i = 1:10
frameCount = frameCount + 1;
rawColorSignal(frameCount) = i;
end
plot(frameCount, rawColorSignal);
grid on
drawnow;
When replacing plot(frameCount, rawColorSignal); with plot(1:frameCount, rawColorSignal); it does:
frameCount = 0;
rawColorSignal = [];
for i = 1:10
frameCount = frameCount + 1;
rawColorSignal(frameCount) = i;
end
plot(1:frameCount, rawColorSignal);
grid on
drawnow;