Class 17, Reading 1

Reading

• GestureWrist and GesturePad: Unobtrusive Wearable Interaction Devices
  
• Rekimoto
  

Outline

• 1. Introduction
  
• 2. Related work
  
• 3. Technological background
  
  • 3.1. Capacitance sensing
    
  • 3.2. On-body networking
    
• 4. GestureWrist A wristband-type input device
  
  • 4.1. Hand-gesture recognition
    
  • 4.2. Forearm movement measurement
    
  • 4.3. Tactile feedback
    
  • 4.4. Combining two sensor inputs
    
• 5. GesturePad: A sensor module for interactive clothing
  
  • 5.1. Sensor configurations
    
  • 5.2. Interaction areas on clothing
    
  • 5.3. Clothes as communication surfaces
    
• 6. Discussion and future research
  
  • 6.1. Combination with output devices
    
  • 6.2. Combination with on-body networks
    
  • 6.3. Sensing other parts of the body
    

Notes

• Introduction
  
  • Important wearable computing feature #1: Supporting hands-free operations or allowing quick changes between normal and operation modes
    
    • Some input devices used with wearable computers need to be held during operation
      
    • With one hand already occupied, performing two-handed tasks becomes difficult
      
    • Glove-type input devices hinder performing real-world tasks
      
  • Important wearable computing feature #2: Social acceptance
    
    • Input devices should be as natural and unnoticeable as possible for use in various social settings
      
    • Many current wearable input devices look unusual or too "hi-tech"
      
      • Often troublesome to wear long-term in everyday situations
        
    • Traditional wearable accessories (e.g., wristwatches, eyeglasses, jewelry, clothes) part of daily life and designed for comfort with long-time use
      
  • "Unobtrusiveness"
    
    • Unobtrusiveness of input devices essential for being used in everyday situations
      
    • One possible way is to embed input sensors to conventional wearable items
      
  • Paper's two example devices:
    
    • GestureWrite
      
      • Wristwatch-type input device that recognizes human hand gestures by capacitively measuring changes in wrist type
        
      • Combined with acceleration sensor mounted to wristband, can be used as command-input device
        
    • GesturePad
      
      • Layer of sensor electrodes transforms conventional clothes into interaction devices (i.e., "interactive clothing")
        
      • Can be attached to area of clothing such as sleeve or lapel
        
      • On capacitive sensing, can detect and read finger motions applied on outside of clothing fabric
        
• Technological background
  
  • Capacitance sensing
    
    • Definition:
      
      • A technique for measuring distances of nearby conductive objects
        
      • Measures the capacitance between the sensor and the object and uses a transmitter and a receiver electrode
        
    • Used for measuring:
      
      • the arm shape by placing both the transmitter and receiver electrodes on a wristband
        
      • finger positions by attaching electrodes on the inside of clothes
        
  • On-body networking
    
    • Based on capacitive sensing, a technique that transmits data through the human body
      
    • Wearable devices can:
      
      • communicate with each other
        
      • automatically authenticate digital devices that are touched
        
    • Technique used to distinguish wearer from other people while interacting with GesturePad
      
• GestureWrist
  
  • About
    
    • A wristwatch-type input device that recognizes human hand gestures
      
    • Capacitively measures:
      
      • wrist-shape changes
        
      • forearm movements
        
    • Consists of:
      
      • two input sensors (capacitance and acceleration sensors)
        
      • one tactile feedback actuator
        
    • fabricated by attaching sensors and actuators to wristwatch
      
    • embedding all sensing elements into wristwatch technically possible, so can be used in any social situation
      
  • Hand-gesture recognition
    
    • Recognizers hand gestures by measuring changes of arm shape on inside of wristband
      
    • Handled by combination of transmitter and receiver electrodes attached to back of watch dial and inside wristband
      
    • When wearer opens and closes hand, wrist's cross-sectional shape changes accordingly
      
    • System can clearly distinguish two hand shapes:
      
      • Grasping
        
      • Pointing
        
  • Forearm movement measurement
    
    • Uses solid-state 2-axis acceleration sensor
      
    • Measures inclination of forearm
      
  • Tactile feedback
    
    • When gesture is recognized, GestureWrist gives tactile feedback to user
      
    • Actuator inside wristwatch dial provides feedback
      
  • Combining two sensor inputs
    
    • By combining two inputs, simple gesture commands were designed
      
    • Two hand shapes:
      
      • Fist
        
      • Pointing
        
    • Six arm positions:
      
      • Palm up
        
      • Palm right
        
      • Palm left
        
      • Palm down
        
      • Forearm up
        
      • Forearm down
        
    • Gesture commands
      
      • Hand shapes used to separate gesture commands into segments
        
      • Two consecutive arm positions (e.g., palm left -> palm down) make up one input command
        
• GesturePad: A sensor module for interactive clothing
  
  • About
    
    • Trial: transform conventional clothes into interactive objects
      
    • Previous work on interactive clothes
      
      • Used metallic yarns woven into fabrics
        
      • Difficult to apply to clothes that already exist
        
    • "Retrofit" approach
      
      • Allows users to attach interactive modules on clothes easily
        
      • Concentrated on making attachment as unnoticeable as possible
        
      • Clothes are highly social media, so attaching obtrusive devices not ideal solution
        
    • GesturePad consists of a layer of sensors that can be attached to inside of clothing
      
      • Wearer can control module from the outside
        
      • Part of clothing becomes interactive without changing appearance
        
  • Sensor configurations
    
    • Consists of three configurations
      
      • Can be attached to inside of clothes
        
      • Controlled from the outside
        
    • Configuration #1: Type-A
      
      • Consists of an array of capacitive sensors
        
      • When user's finger is close enough to sensor surface, sensor grid recognizes finger position
        
      • E.g., when module is placed on inside of lapel, finger stroke gesture on lapel becomes computer input
        
    • Configuration #2: Type-B
      
      • Consists of transmitter and receiver layer separated by shield layer
        
      • When user's finger is within proximity of GesturePad, wave signal from transmitter electrode transmitted to receiver one
        
      • Could be put in trouser pocket and operated from outside of pocket
        
      • One benefit is that it can prevent other people from interacting with sensor
        
    • Configuration #3: Type-B'
      
      • Same sensor structure as Type-B
        
      • Differs from Type-B by placement of transmitter and receiver electrodes (reversed)
        
  • Interaction areas on clothing
    
    • Several variations of GesturePad attached to different clothes parts
      
      • Several parts could be assigned as input areas and used in combination
        
      • For user's convenience:
        
        • Frequently used commands assigned to easily accessible areas (e.g., lapels, sleeves)
          
        • Rarely used commands assigned to elbows or knees
          
      • Traditional devices (e.g., mice)
        
        • Requires changing operation mode or selecting menu item before actually performing operation
          
        • When interacting with wearable computers, this step is troublesome
          
  • Clothes as communication surfaces
    
    • Another feature of GesturePad is ability to communicate with other digital devices
      
    • Can typically be applied to control data communication between digital devices nearby
      

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