This article proposes a multispectral system that uses the analysis of the spatial distribution of color and spectral features to improve the detection of skin cancer lesions, specifically melanomas and basal cell carcinomas. The system consists of a digital camera and light-emitting diodes of eight different wavelengths (414 to 995 nm). The parameters based on spectral features of the lesions such as reflectance and color, as well as others empirically computed using reflectance values, were calculated pixel-by-pixel from the images obtained. Statistical descriptors were calculated for every segmented lesion [mean ( x ˜ ), standard deviation ( σ ), minimum, and maximum]; descriptors based on the first-order statistics of the histogram [entropy ( E p ), energy ( E n ), and third central moment ( μ 3 )] were also obtained. The study analyzed 429 pigmented and nonpigmented lesions: 290 nevi and 139 malignant (95 melanomas and 44 basal cell carcinomas), which were split into training and validation sets. Fifteen parameters were found to provide the best sensitivity (87.2% melanomas and 100% basal cell carcinomas) and specificity (54.5%). The results suggest that the extraction of textural information can contribute to the diagnosis of melanomas and basal cell carcinomas as a supporting tool to dermoscopy and confocal microscopy.

In this study we show a novel double-pass configuration to correct the spherical refractive error by means of an electro-optical liquid lens. The proposed method enables spherical correction in the-12 D to +7 D range without movable parts using an electro-optical liquid lens. We have measured the optical performance of the spherical corrector in terms of power, pupil size and optical quality verifying that it fits the requirements to be applied to a double-pass system. We have also evaluated the performance of the proposed method in patients by comparison with a conventional double-pass system using a Badal optometer.

We present a handheld scanning system for measuring in-vivo the 3D topography of the human skin surface. The system has been envisaged for analyzing the 3D shape of skin cancer lesions, providing a more precise characterization of the lesions compared with the conventional examination done by using the naked eye and dermoscopy methods. The 3D scanning system is composed of cost-effective and commercially available components, including two monochrome cameras placed in a stereo configuration, a color camera, and a compact projector unit. The 3D measuring principle is based on the technique of stereovision combined with the projection of structured light patterns. A first scanning prototype has been recently developed for imaging skin surface areas of 19 x 14 mm 2. A graphical user interface (GUI) has been also implemented to operate with the prototype. Preliminary experimental results showing the performance of this initial prototype for imaging different skin surface zones are also presented.

Abstract. We have studied the possibility of improving the performance, simplifying, and reducing the cost of a double-pass system by the use of alternative technologies. The system for correcting the spherical correction has been based on a focusable electro-optical lens, and a recording device based on CMOS technology and a superluminescent diode (SLED) light source have been evaluated separately. The suitability of the CMOS camera has been demonstrated, while the SLED could not break the speckle by itself. The final experimental setup, consisting of a CMOS camera and a laser diode, has been compared with a commercial double-pass system, proving its usefulness for ocular optical quality and scattering measurements.

This study proposes the combination of multispectral and 3D imaging sensors to improve the detection of skin cancer. The multispectral system consists of a CCD digital camera and light emitting diodes (LED) of eight different wavelengths (414 nm to 995 nm) with a working distance of 4 cm and a field of view of 15 mm × 20 mm. Parameters based on spectral features of the lesions such as reflectance and color as well as others empirically computed using reflectance values were calculated pixel by pixel from the images obtained. The 3D system is composed of two monochrome CCD cameras placed in a standard stereo geometry, a light picoprojector and a color camera, both located between the two monochrome cameras. All cameras had an objective lens with fixed focal length (25 mm) with a working distance of 110 mm, obtaining a field of view of 19 × 14 mm. Parameters based on the shape, border irregularity and height of the lesion were obtained by a stereovision technique combined with the projection of a sinusoidal pattern set shifted over the skin. More than 80 skin lesions including malignant and benign lesions were analyzed by means of both sensors and the combination of parameters allowed for a higher detection of melanomas (Sensitivity: 93%, Specificity: 54%). Therefore, the proposed sensors could be useful as a supporting tool to current methods used in dermatology such as dermoscopy and confocal microscopy. This study is within the framework of the European Project DIAGNOPTICS "Diagnosis of skin cancer using optics" (ICT PSP seventh call for proposals 2013).