Pressure ulcers are a significant problem to elders and people with mobility impairments and have been recognized as a public health issue. The most common and effective means to prevent pressure ulcer development is the identification of erythema via visual skin inspection. A significant need exists for a technology that can help health care professionals and caregivers identify areas of erythema before necrosis progresses. Our prior work suggests that it is feasible to use three or four spectral bands centered at absorption peaks of skin chromophores to detect erythema in persons with dark skin with accuracy, sensitivity and specificity all over 90%. However, only bulky and expensive multispectral systems are currently available which use either traditional optical filters or methods of dispersing light in order to form images at discrete wavebands. They are not suitable for clinical and other applications which require compact lightweight systems. Clinical practitioners in the health care and rehabilitation fields generally stayed away from multispectral imaging technologies due to their extremely high costs and lack of portability. The key technical advantage in our approach is a novel custom filter mosaic which has been successfully designed and fabricated using lithography and vacuum multi layer film technologies. The filter has been integrated with imaging sensor CMOS and CCD. The filter incorporates four or more different wavelengths within the visual to near-infrared range each having a narrow bandwidth of 30nm or less. Single wavelength area is chosen as 20.85m x 20.85m. This design permits a multispectral image to be acquired in a single exposure, thereby providing overwhelming convenience in multi spectral imaging acquisition. For erythema detection, the four chosen wavelengths are the absorption spectra related to chromophores bilirubin, hemoglobin and water and center on 540, 577, 650, and 970nm. The research plan for Phase I will refine the core technology and prepare it for clinical testing. We will: 1) design, test and optimize the illumination system, 2) accurately integrate the filter mosaic with an imaging sensor and classify the pixels of the imager into four multispectral images, 3) develop and evaluate algorithms that improve the spatial resolution of the obtained multispectral image, and 4) characterize the filter mosaic and determine the technical specifications needed for the clinical testing prototypes.
Pressure ulcers are a significant problem for the elderly and people with mobility impairments and recognized as a critical public health issue. A significant need exists for technology that can help health care professionals and caregivers identify areas of erythema before necrosis progresses. Prospect Photonics is developing a novel mosaic filter multispectral imager for real time early stage pressure ulcer detection.
