4.1.1.1 Gesture Recognition

The Colibri Suite’s gesture recognition model detects and classifies hand movement patterns performed inside the sensing area.

Using advanced stochastic classification based on Hidden Markov Model (HMM), industry best gesture recognition rate is achieved.

Flick Gestures

Figure 4-2. Flick Gestures

A flick gesture is a unidirectional gesture in a quick flicking motion. An example may be a hand movement from West to East within the sensing area, from South to North, etc.

Hold and Presence Gestures

Detection of a hand within a configurable detection area. After the hand is detected as being present in this area, a timer will be started. If the hand stays within the detection area until a certain timer value is reached, the Presence gesture is detected. The timer value is configurable. The Presence gesture is typically used for lighting up back-lights, as if the hand is in the detection area and does not move; a second timer is started.

Presence and Hold gestures are triggered upon a timeout in a defined status flag. If a Status flag is active during a certain amount of time, after its last rising edge, the corresponding gesture is triggered.

The status flags that can trigger one of these gestures are:
  • Hand Presence flag is active while the user's hand is in the sensing space
  • Hand Inside flag is active while the user's hand is in the sensing space approximately centered above the sensor
  • Hand Hold flag is active while the hand is not moving and one of the above status flags is active; the selection depends on ActiveOutside.

The behavior of the status flags and corresponding gestures can be adjusted to suit a specific application.

The Gesture and Presence/Hold State visualization windows offer immediate feedback upon adjustment.

The adjustable parameters are:

  1. ActiveOutside
    - Chooses if Hand Hold flag and Presence gesture can be active when the user is outside the sensor, but still in sensing space.
    • ActiveOutside checked (default) means that Hand Presence is required to set Hand Hold and that Presence Duration starts counting on the rising edge of Hand Presence status flag.
    • ActiveOutside unchecked means that Hand Inside is required to set Hand Hold and that Presence Duration starts counting on the rising edge of Hand Inside status flag.
  2. Presence Duration

    – This is the time during which the selected status flag must be active to trigger a Presence gesture. This time starts counting on the last rising edge of the selected status flag. The gesture is only triggered once for each rising edge of the flag.

  3. Hold Duration

    – This is the time during which the Holding Hand flag must be active to trigger a Hold gesture. This time starts counting on the last rising edge of the Holding Hand flag. The gesture is only triggered once for each rising edge of the flag.

  4. Hold Tremble Threshold

    – This value specifies how much the hand can move and still be considered as holding. For high values, the hand can move while the Hand Hold flag is still high. For low values, only a slight movement is necessary to clear the Hand Hold flag.