VideoInput properties reset when calling start(vidobj)

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Pierre Margerit
Pierre Margerit 2022-4-19
评论： William 2025-1-27
Hello everyone,
I am struggling on a problem about Image Acquisition Toolbox.
After creating a VideoInput object, I want to tune some source properties (like Focus, Exposure, etc) then start an acquisition with the custom settings.
I am able to change the desired settings programmatically, with or without a preview running in background to see the effects of the changes in the source properties.
However, when I start the VideoInput using start(vidobj), it looks like all the settings are reset to their default value: the focus is lost, the exposure is bad, etc.
And if I want to start the VideoInput before setting the properties, MATLAB returns an error message saying that the properties are Read-Only on Running mode..
Any ideas on how to solve this ?
Thank you by advance, Pierre
  1 个评论
William
William 2025-1-27
I am having the same problem with a gentl / genapi camera connected to a framegrabber. I set a number of parameters, including frame rate and exposure time. I validate in the manufacturers tool of the framegrabber that everything is setup correctly. Then I run the "start" from Matlab, and I can see that the settings are overwritten. What can I do...?

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回答（1 个）

Vidip
Vidip 2023-12-1
I understand you are facing problem where the settings are reset when you start the video input, this is not the expected behaviour as to set the value of a video input object property or a video source object property, you reference the object property as you would a field in a structure, using dot notation. Some properties are read only; you cannot set their values. These properties typically provide information about the state of the object. Other properties become read only when the object is running. To view a list of all the properties you can ‘set’, use the ‘set function’, specifying the object as the only argument.
To understand the problem properly, please send the code or there might be some issue with implementation of code so you can verify the procedure followed:
  1. Create a Video Input Object: Create a Video Input object using the ‘videoinput’ function. This object represents the physical image acquisition device and provides methods for configuring and controlling the acquisition process.
  2. Set Device Properties: Configure the properties of the Video Input object using its various methods. These properties include the device name, video format, frame rate, and other relevant settings.
  3. Start Image Acquisition: Initiate the image acquisition process using the ‘start’ method of the Video Input object. This will begin capturing frames from the connected device.
  4. Acquire Frames: Retrieve captured frames using the ‘getsnapshot’ method of the Video Input object. This method returns the current frame as an image array.
  5. Stop Image Acquisition: Terminate the image acquisition process using the ‘stop’ method of the Video Input object. This will halt the capture of frames.
  6. Cleanup: Properly clean up resources by deleting the Video Input object using the delete function. This ensures that the connection to the device is closed and resources are released.
For further information, refer to the documentation links below:

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