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+The following arguments are defined in the constructor of class OpenGaze, which you can find in the `opengaze.cpp` source file.
+* root_dir: A root directory which contains a "content" folder and "default.cfg" file. By default, it is `/OpenGaze` under your home directory.
+* input_tupy: The type of input data, which can be: `camera`, `video`, or `directory`. The default value is `camera`.
+* input: The input value corresponding to the input type. It must be: the camera id for the input type `camera`, the absolute video file name for the input type `video, or the folder name for the input type `directory`. The default value is 0 for the camera id.
+* gaze-method: Currently, we only support the full-face appearance-based gaze estimation, which is `MPIIGaze`.
+* output: The directory to output to. The default value is the directory of the input video file or input directory or the `root_dir` for the input type `camera`
+* calib_caemra: Configuration file of the calibrated camera. The default value is `/OpenGaze/content/calib/calibration.yml`
+* calibration_screen: Configuration file of the calibrated camera-screen. The default value is `/OpenGaze/content/calib/monitor_laptop.yml`
+* gpu_id: The ID of the GPU to use. The default value is `0`.
+* debug: Bool value to indicate enabling debug mode or not. For debug mode, the system will draw the gaze direction on the face image and show this on the screen. The default value is `false`
+* face_model: Bool value to set to use either the full face model or eye model for MPIIGaze method. The default value is `true`, i.e. the full face model is used.
+* save_video: Bool value to indicate whether to save the debug mode video or not. The default value is `false`.
+* number_user: integer value to set the maximum number of users to track. The default value is 5.
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