MATLAB: How to add a live image to UIAxes in App Designer for MATLAB R2016b

app designerlive imageMATLABpreviewr2016bvideowebcam

I am using MATLAB R2016b on a Mac. I have tried the following which results in a black box with the specified dimensions (640×480) showing up in the UIAxes:

vid = videoinput('macvideo', 1);
hImage = image(app.UIAxes1, zeros(640,480,3));
preview(vid, hImage);

I get this error message:

Error using imaqdevice/preview (line 176)
There is no ALimMode property on the UIAxes class.

Is preview not supported in App Designer yet?

Best Answer

The Image Acquisition Toolbox PREVIEW function does not support UIAXES in R2016b yet, but the toolbox team is aware of the customer need.

Related Solutions

MATLAB: How to preview live video in App Designer using videoinput and preview

In order to preview the video in your uiaxes, you can create an image and preview the video on that image:

% Image acquisition
vid = videoinput('winvideo',1);
% Create blank image
hImage = image(app.UIAxes,zeros(720,1280,3)); %If image resolution is 1280x720
pause(2)
% These lines set proper aspect ratio
app.UIAxes.XLim = [0,1280];
app.UIAxes.YLim = [0,720];
app.UIAxes.XTick = [];
app.UIAxes.YTick = [];
pbaspect(app.UIAxes,[1280,720,1])
% Preview the image
preview(vid,hImage)

MATLAB: How to change the resolution of images I acquire with the Image Acquisition Toolbox

The resolution of images acquired from a camera using the Image Acquisition Toolbox is not directly set by MATLAB. Instead, it is dependent upon the video format of the hardware device. Each video format has a specific resolution associated with it. Once a video format is chosen, the associated resolution is used.

As an example, if you have a 'winvideo' compatible imaging device connected to your system, the following command returns more information about the available image acquisition hardware:

info = imaqhwinfo('winvideo')

In order to see a list of supported video formats for this device, type:

info.DeviceInfo.SupportedFormats

This results in an output similar to the one shown below:

 ans = 
     'RGB24_160x120'    'RGB24_176x144'     'RGB24_320x240'    'RGB24_352x288'    'RGB24_640x480'

Select a video format and associate it with a video object when creating the object in the MATLAB workspace. For example:

obj = videoinput('winvideo',1, 'RGB24_640x480')

Sets the video format of the camera to acquire RGB images at a resolution of 640X480. The video object's 'VideoResolution' property specifies the resolution of acquired images. This property, however, is read-only and can not be directly set.

Best Answer

Related Solutions

MATLAB: How to preview live video in App Designer using videoinput and preview

MATLAB: How to change the resolution of images I acquire with the Image Acquisition Toolbox

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