Recently, Martin implemented a new camera interface in the ITU Gaze Tracker. This interface allows us to make all the code in the tracking library camera-independent, since now all camera-specific features are taken care of by the interface. It also makes it easier to add support for new cameras, so if you have a camera you would like to add support to (for example Point Grey cameras) and have some coding skills, feel free to give it a try!
The camera/device management has been extracted into a new namespace, GTHardware. When the Camera class is created it will check which devices are connected and initialize the device. Each device extends the CameraBase class which contains a set of methods that are required. The GTHarware.Camera contains a static singleton reference to the active camera which can be accessed through the Instance property.
Required methods
| Name | Description |
| Initialize | Prepares and initializes the camera, creates handle, allocates image memory etc |
| Start | Starts capture, raises OnImage event of type ImageEventArgs when a frame arrives |
| Stop | Stops capture |
| SetROI | Takes a System.Drawing.Rectangle and sets the Region of Interest on cameras supporting this, this is determined by fixed property IsSupportingROI |
| GetROI | Returns System.Drawing.Rectangle of the set ROI |
| ClearROI | Clears the Region of Interest |
| Cleanup | Disposes memory, closes handles and stops camera if running |
Required properties/events
| Type | Name | Description |
| int | Width | Gets the current (last) image width |
| int | Height | Gets the current (last) image height |
| int | DefaultWidth | Gets the width of the full frame image (non-roi) |
| int | DefaultHeight | Gets the height of the full frame image (non-roi) |
| int | FPS | Current Frames Per Second |
| bool | IsSupportingROI | False for DirectShow devices, true for some machine vision cameras |
| bool | IsROISet | Returns true if the Region of Interest has been set |
| bool | IsSettingROI | Returns true if the camera uses an asynchronous method to set Region of Interest and this operation has not completed yet |
| event | OnImage | Tracker subscribes to an event handler of type ImageEventArgs which is raised when a new frame arrives. It contains a Emgu/OpenCV image of type Image |
Edit: See the discussion on the forum that concerns adding new devices.