2D Versus 3D Foot Imaging Systems
Digital Orthotics. click
There is a significant level of confusion in the Medical Industry as to the efficacy and value in the available formats for foot and total load bearing analysis.
Imaging systems are broken into three modalities;
- Light or Optical
- Pressure Ink and Pizo Resistive Sensor Imagers
- Pneumatic - Mechanical
Light or Optical Imagers - 2D and 3D
- They are Static Systems which means they usually are not portable and provide Static analysis only.
- They are optical, and therefore provide a 1:1 scale image of the foot. Most systems are 2D (Photostat or Color Scanners) and provide and length (x) and width measurement (y) of the foot. Laser Optical Imagers are 3D and provide a length (x) and width (y) and height (z) measurement.
- Fringe Light is a low cost method for attaining 3D imaging, however the technology is very unstable and unreliable and for the most part has been abandoned.
Pros (+)
- 3D Laser Systems are excellent in providing a non weight bearing image of the foot, (which is a 3D appendage of the body) however they are dependent on proper positioning of the foot by technician or physician.
Cons (-)
- 2D Optical Imagers are NOT a valid method for imaging the foot since the foot is a 3D appendage of the body. Many of the foot imagers in the industry today are simple 2D Imagers. They are cheap to produce, however they do not provide adequate information for the manufacturing of custom orthotics. Some of the companies use software to assimilate a 3D imager, however this is not geometric and is a estimation of (z) axis based on shades of grey.
- The 3D Laser, despite their accuracy are reliant on the Physician or Skilled Technician aligning the foot in a palpated "Neutral Joint Position", (Sub Talar Joint, Midtarsal Joints and 1st Ray). If the positioning of the foot is not proper, then the resultant Laser Imager likewise is not accurate.
- There is no Dynamic data relative to function. This is a key element in engineering a functional device. We need to know how the foot works and the elements of Mass, Motion, Pressure, Balance, Symmetry, Gait and 3D Geometry are critical elements in understanding how we need to approach biomechanical control.
- Laser are also delicate and if dropped or banged, can cause the optical alignment to be off. This requires re-calibration which can be costly.
Examples of 2D Optical Systems
- Tom Cat
- Pedalign
- PAL
- Optical Imaging System (Digital Orthotics Inc)
- Dr Zen
Examples of Laser Systems
- G3 (Digital Orthotics Inc.)
- Bergmann
- Sharp Shape
Conclusion
Static analysis resolves part of the problems in the analysis of biomechanical diseases. 2D systems are not a valid method for making Custom Orthotics. Laser systems are highly dependent on the skill of the operator or physician.
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Pressure Systems - 2D and 3D
- All Pressure analytical systems are 2D except for one, (3DO - 3D Orthodynamics made by Digital Orthotics).
- They provide Static and Dynamic information. Gait analysis and other modalities such as balance and pressure can be informative for testing but for the manufacturing of Orthotics, they fall significantly short in providing manufacturing information due to the fact they are 2D systems.
- They are portable
- They analyze linear pressure and motion analysis
Pros (+)
- Portable
- Provide dynamic information regarding Gait Analysis, body balance, and pressure
- 3DO is the only system which is Static and Dynamic and provides 3D data relative to Mass Displacement Analysis, Motion Analysis, Pressure (linear and sheer), Body Balance, Symmetry, Gait Analysis and 3D Geometry.
- 3DO determines Neutral Joint Positioning through Software analysis of Static and Dynamic data.
Cons (-)
- Except for 3DO, you can not make Orthotics with any sense of adequate control and if they are made, it is done through estimation of data only.
- No 3D data
- Can not make Custom Orthotics with any degree of accuracy
Examples of Systems
- FootMaxx - 2D Scanner
- Paratech - 2D
- Tekscan - 2D
- The Orthotic Group - TOG 2D Scanner
- Alibaba
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Pneumatic Pin - 3D
- Static Analysis Only
Pros(+)
- 3D Laser Systems are excellent in providing a non weight bearing image of the foot, (which is a 3D appendage of the body) however they are dependent on proper positioning of the foot by technician or physician.
Cons(-)
- The 3D Laser, despite their accuracy are reliant on the Physician or Skilled Technician aligning the foot in a palpated "Neutral Joint Position", (Sub Talar Joint, Midtarsal Joints and 1st Ray). If the positioning of the foot is not proper, then the resultant Laser Imager likewise is not accurate.
- There is no Dynamic data relative to function. This is a key element in engineering a functional device. We need to know how the foot works and the elements of Mass, Motion, Pressure, Balance, Symmetry, Gait and 3D Geometry are critical elements in understanding how we need to approach biomechanical control.
Example of System
- Amfit
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3D Stereoscopic Laser Imager
G3
Advantages
- Tremendous accuracy and is dependent on proper foot positioning by Physician or Technician
- No Plaster mess
- Portable
- Direct to CNC Milling pathway on Digital Imager Live
Disadvantages
- Requires technical skill
- Delicate Laser Optics
- No Dynamic Gait or Reports
Optical Imager System (2D)
Advantages
- Low Cost Static Imager ($1500.00)
- Works on Digital Imager Live
- Excellent for Custom Orthotics - Foot Sizing - Footwear Manufacturing -Plantar Lesions - Extensions
- Portable and affordable
Disadvantages
- No Dynamic Gait or reports
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