MATLAB: Appdesigner: Workaround Functionality PickableParts

app designergige cameraguideimage acquisitionImage Acquisition ToolboxMATLAB

Hi, I am trying to migrate myCameraGUI into AppDesigner. There are some issues in the Migration Report.

For example, the fucntionality Pickableparts is not supported in the App Designer with GUIDETAG cameraAxes. Are there any other similar functionality in the app designer?

I basically want to click on a button, to start and stop a camera stream, and another button to grab the image (snapshot) and save it to .mat file. I have even tried to write the similar code in app designer from scratch but it doesn't react to anything after clicking the button once, so i don't know how to solve that. 'myCameraGUI' does exactly what i want and i don't have any weird loading effects when I want to display the stream in the GUIDE.

I am very new with GUI and App designer, so any help appreciated.

Best Answer

It's not clear why you need pickable parts. Does the user need to draw an region on the image or is the area pre-defined?

If the user needs to draw an area, explore the Rectangle object.

Related Solutions

MATLAB: App Designer: How to use a camera in different Callbacks

Hi,

Folllowing is the code and app design

classdef app1 < matlab.apps.AppBase
    % Properties that correspond to app components
    properties (Access = public)
        UIFigure  matlab.ui.Figure
        UIAxes    matlab.ui.control.UIAxes
        UIAxes2   matlab.ui.control.UIAxes
        Button    matlab.ui.control.Button
    end
    
    properties (Access = public)
        cam;
    end
    
    % Callbacks that handle component events
    methods (Access = private)
        % Code that executes after component creation
        function startupFcn(app)
            app.UIAxes2.Visible = 'off';
            evalin("base", 'clear cam');
            app.cam = webcam;
            frame = snapshot(app.cam);
            im = image(app.UIAxes, zeros(size(frame), 'uint8'));
            axis(app.UIAxes, 'image');
            preview(app.cam, im);
        end
        % Button pushed function: Button
        function ButtonPushed(app, event)
            img = snapshot(app.cam);
            image(app.UIAxes2, img);
            app.UIAxes2.Visible = 'off';
        end
    end
    % Component initialization
    methods (Access = private)
        % Create UIFigure and components

        function createComponents(app)
            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';
            % Create UIAxes
            app.UIAxes = uiaxes(app.UIFigure);
            title(app.UIAxes, 'Title')
            xlabel(app.UIAxes, 'X')
            ylabel(app.UIAxes, 'Y')
            app.UIAxes.Position = [26 270 300 185];
            % Create UIAxes2
            app.UIAxes2 = uiaxes(app.UIFigure);
            title(app.UIAxes2, 'Title')
            xlabel(app.UIAxes2, 'X')
            ylabel(app.UIAxes2, 'Y')
            app.UIAxes2.Position = [25 43 300 185];
            % Create Button
            app.Button = uibutton(app.UIFigure, 'push');
            app.Button.ButtonPushedFcn = createCallbackFcn(app, @ButtonPushed, true);
            app.Button.Position = [447 249 100 22];
            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end
    % App creation and deletion
    methods (Access = public)
        % Construct app
        function app = app1
            % Create UIFigure and components
            createComponents(app)
            % Register the app with App Designer
            registerApp(app, app.UIFigure)
            % Execute the startup function
            runStartupFcn(app, @startupFcn)
            if nargout == 0
                clear app
            end
        end
        % Code that executes before app deletion
        function delete(app)
            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

Error you are facing instantiates that the code is not able to access the camera object at that instant.

Hope it helps!!

MATLAB: Video preview has growing delay when used in uifigure, but not in normal figure

I got an answer from the MATLAB support team:

After collaborating with my colleagues I figured that this is a known limitation with the "uiaxes" performance in terms of rendering the images. Currently, "uiaxes"/"uifigure" (javascript based) does not support high frame rates like the traditional MATLAB figure window (java based) and the frames passed to the "uiaxes" are queued for rendering, this is causing the memory increase they noticed. For the same reason, it will cause a lag which worsens with larger images and high acquisition frame rates if the acquisition is running for a long duration .

Until the performance bottleneck in the "uiaxes" is addressed, there is little we can do to help you, if you goal is to have the live preview running in the app.

Having said that, for the time being, I would suggest you to open the preview in traditional MATLAB figure window outside of the app and i believe you have already tried this.

Another thing to experiment is to turn the imaqmex's "slowpreview" flag which currently sets a max limit of 10 frames for previewing. However, with the "uiaxes" rendering performance even 10 FPS might be high. Following is the code to enable slow preview.

>> imaqreset

>> imaqmex('feature', '-slowpreview', 'true')

>> vid = videoinput(...)Please note that this is an undocumented feature and it could change and/or be removed in the future.

Additionally, lowering the resolution and/or ROI can help as this decreases the load on the "uifigure".

Best Answer

Related Solutions

MATLAB: App Designer: How to use a camera in different Callbacks

MATLAB: Video preview has growing delay when used in uifigure, but not in normal figure

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