D7.1 - Spectral Imaging Skin Probe for Chronic Wounds Therapy Evaluation
- SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
- Proceedings SENSOR 2011
- D7 - Medical II
- F. Erfurth, B. Nyuyki, A. Scheibe, W. Schmidt - GMBU e.V., Jena (Germany)
- 638 - 643
We present a skin imaging probe for an objective assessment of chronic wounds with regard to the healing process. It is based on the principle of Spectral Imaging, which represents a combination of classical spectroscopy and digital image processing, whereby a spectrum is recorded for each pixel simultaneously. Component analysis or other classification methods can be applied to the spectral data, for instance a score is computed that describes the state of a wound numerically.
The probe consists of an imaging spectrograph that spectrally disperses light from the sample and projects it on a camera chip. A matrix of micro lenses connected to 109 optical fibers in the sensor’s hand piece gathers the remission from the skin, which is illuminated through 144 fibers with the light of a halogen lamp. The micro lenses in the hand piece for illuminating and detection are arranged in a grid of 40 x 40 mm2 and allow for image capture within a range of up to 10 mm largely independent of distance of the probe to the skin. The influence of ambient lighting can be compensated for by fast successive measurements with and without integrated probe lighting.
The determination of the wound condition is done by measuring and comparing the wound spectra with a library of spectral signatures. To generate this library, measurements were carried out on patients with chronic wounds. For the purpose of calibration an experienced physician determined on an eight-level scale a wound specific value using a set of criteria (wound score according to Wollina). The automatic determination of the healing index from the spectral data captured with the skin probe is done through the analysis of the hyperspectral remission signals. The determination of the similarity of these signals to those in the library of known wound spectra is carried out by means of spectral angular mapping. With these results not only overall statements about the healing prospects of the wound can be made, but also certain parts of the wound can be evaluated.
The skin imaging probe provides a universal tool for spectroscopic evaluation. In the area of skin diagnosis, the objective determination of wound scores could be demonstrated. The evaluation of spectral data of chronic wounds taken with the probe resulted in an agreement with the judgment of a physician in 69% of the cases.