3D is a current revolution in the imaging of the skin, skin structure and skin pathologies. 3D can serve multiple purposes ranging from photo-documentation to quantitative measurement with a quality and an accuracy far better than what can be achieved with simple 2D pictures.
In addition to the classical but quite expensive tomography imaging systems (CT, MRI, Ultrasound, Confocal microscopy…), 3D surface analysis of the skin can be obtained via two broad classes of technology. “Active vision”, by which strips or patterns are projected onto the surface and then measured via a (generally single) image – and “passive vision”, which is pure observation of the subject, generally based on Stereovision. Stereovision has the advantage of mimicking human vision, therefore enabling 3D stereo-visualization as well as 3D surface reconstruction. It is generally more compact and easier to manipulate than active vision tools that a need power supply and camera video mode to record the results of projected strips.
Between 3D stereovision technologies, auto-calibration must be distinguished from absolute calibration. With auto-calibration techniques, one can reconstruct a surface, generally with less detail than the absolute calibration system. Absolute quantitative measurements of 3D surfaces and 3D volumes are only possible using absolute calibration. Although cheaper than active vision systems, stereovision systems are still one order of magnitude more expensive than 2D photography, due to the high level of accuracy and calibration process in their design.
QuantifiCare has developed the 3D LifeViz, an absolute calibration stereovision technology, with field of view intended for face and breast imaging. It is now issuing a second generation of systems with the LifeViz “Micro”, designed for a 5x4cm field. LifeViz Micro is very compact and easy to use, it enables stereo-visualisation and quantitative measurements of fine wrinkles, crows feet, acne lesions, acne scars, BCC lesions, small ulcers and scars, striae, varicose... In some conditions, it is accurate enough to access skin texture information.
We are presenting the result of extensive validation experiments of the 3D LifeViz micro system, demonstrating an in-depth accuracy of up to 8 microns in some conditions. Further developing the accuracy of the system is limited by factors such as skin transparency which hinder the assessment of accuracy and ground truth.
Finally, we are presenting a variety of clinical applications including, acne, scars, fine wrinkles and basal cell carcinoma, and also including a presentation of the different quantitative tools available in the 3D quantification package. This makes the 3D stereovision technology an ideal tool for research labs working on skin.ISBS BESANCON CONGRESS 9 - 12 SEPTEMBRE 2009