Ferran Sanabria

Multispectral imaging system based on light-emitting diodes for the detection of melanomas and basal cell carcinomas: a pilot study

Abstract. 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 (Ep), energy (En), and third central moment (μ3)] 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.

Handheld 3D scanning system for in-vivo imaging of skin cancer

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.

Technical improvements applied to a double-pass setup for performance and cost optimization

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.