Optical design improvement for noncontact skin cancer diagnostic device

Multispectral diffuse reflectance imaging and autofluorescence photo-bleaching imaging are methods that have been investigated for use in skin disorder diagnostics. In response to the ever-increasing incidence of skin cancer in light skinned populations a new device has been designed incorporating both of these methods. The aim of the study was to create a device that is most efficient in terms of hardware and software parameters for the screening of malignant and benign skin lesions. A set of 525 nm, 630 nm and 980 nm LEDs were used to illuminate the skin area at three wavelengths [1] and a set of 405 nm LEDs were used to induce the skin autofluorescence [2]. For a more homogenous illumination of investigated skin area the optimal placement for LEDs in a cylindrical case was found. The requisite spacing from the camera lens was taken into account to produce a focused RGB image. The geometrical shape of the device allows to capture images of skin that are illuminated solely by the diodes without interference from sunlight or other nearby light sources. Polarizing filters were used to decrease glare effects, therefore preventing image overexposure of very reflective skin areas. 515 nm long pass filter was used to enable the 405 nm excitation while capturing autofluorescence images of the skin. Further improvements to the quality of the diagnostic data can be achieved using reference images to track homogeneity of the intensity and then applying a compensating algorithm on the subsequent screening images. These and other design considerations serve to realize the full potential of the diagnostic method. Results of clinical approbation to assess the efficacy of the new device to diagnose malignant skin lesions will be demonstrated.