User Perception Framework

After laying the foundational architecture of the Botender framework, our next step is to implement the User Perception Framework.

Framework Components and Their Roles

  • The EmotionDetector predicts the customer’s emotional state by utilizing a Support Vector Machine (SVC) model. The model is trained based on the dataset DiffusionFER provided on Studium. It is loaded from a pre-trained file.

  • The FacialExpressionDetector detects faces in a frame and returns their coordinates as rectangles. It also extracts facial features, landmarks and action units, from the detected faces and returns them. Thus, the detector provides the raw data for the Emotion detector.

  • The SpeechDetector captures and processes spoken language from customers. The furhat_remote_api is used for capturing speech. To indicate active listening the Furhat’s LED is turned on.

  • The DetectionWorker runs as a separate process and ensures that Botender is responsive, even under the load of real-time video processing. It handles the face and emotion detection. This class provides the following features:
    • Utilizes FacialExpressionDetector and EmotionDetector for processing frames.
    • Manages a shared array for frame data and uses events for process synchronization.
    • Implements a method to detect emotion periodically based on frame counts and skips.
  • The PerceptionManager manages, and initializes the DetectionWorker process, as well as the overall perception workflow. It uses multiprocessing primitives for inter-process communications:
    • a mp.Queue for task management
    • a mp.Pipe for result transmission
    • shared memory mp.Array
    • synchronization between main process (PerceptionManager) and child process (DetectionWorker) through initializing mp.Event objects

    Furthermore, the class contains methods to trigger emotion detection and render results (faces and emotions) onto the current frame.

Written on December 6, 2023