Publications

Confocal reflectance microscopy (CRM) enables the in-vivo observation of the skin at a nearly histologic resolution. Since melanin represents a strong source of contrast, this technique appeared particularly indicated for the study of melanocytic lesions. Cytological and architectural features of melanocytic skin lesions were studied on 25 melanomas and 50 atypical melanocytic nevi employing CRM (Vivascope 1000, Lucid Inc., USA) and digital dermoscopy (Videocap 200, DS-Mediroup, Italy). All lesions were excised for diagnostic confirmation. Some differences in CRM features were observed between benign and malignant lesions: in melanocytic nevi, cells were usually round to oval, mainly located in the basal layers or clustered into nests within the papillary dermis. Melanomas were characterized by numerous large cells within the superficial layers of the epidermis, suggesting a pagetoid fashion, and by cells polymorphic in size and shape mainly located in the basal layer, sometimes interrupted by small dermal papillae irregularly distributed throughout the lesion, owing to disarrangement of the normal architecture of the rete ridges. Moreover, large irregular cells with refractive cytoplasm and eccentric dark nucleus infiltrating dermal papilla and cell clusters with a multilobulated feature constituted by sparse cells or with a cerebriform aspect were specifically observed in melanomas. Although preliminary and based on a limited number of cases, these findings show the potential of this technique for the noninvasive diagnosis of clinically difficult lesions.

People tracking deals with problems of shape changes, self-occlusions and track occlusions due to other interfering tracks and fixed objects that hide parts of the people shape. These problems are more critical in indoor surveillance and in particular in home automation settings, in which the need to merge information obtained form different cameras distributed around the house calls for the integration of reliable data obtained during time. Therefore, tracking algorithms should be carefully tuned to cope with occlusions and shape changes, working not only at pixel level but also at region level. In this work we provide a novel technique for object tracking, based on probabilistic masks and appearance models. Occlusions due to other tracks or due to background objects and false occlusions are discriminated. The classification of occluded regions of the track is exploited in a selective model update. The tracking system is general enough to be applied with any motion segmentation module, it can track people interacting each other and it maintains the pixel to track assignment even with large occlusions. At the same time, the model update is very reactive, so as to cope with sudden body motion and silhouette's shape changes. Due to its robustness, it has been used in different experiments of people behavior control in indoor situations.

Background: Identification of dark areas inside a melanocytic lesion (ML) is of great importance for melanoma diagnosis, both during clinical examination and employing programs for automated image analysis. Objective: The aim of our study was to compare two different methods for the automated identification and description of dark areas in epiluminescence microscopy images of MLs and to evaluate their diagnostic capability. Methods: Two methods for the automated extraction of ´absolute´ (ADAs) and ´relative´ dark areas (RDAs) and a set of parameters for their description were developed and tested on 339 images of MLs acquired by means of a polarized-light videomicroscope. Results: Significant differences in dark area distribution between melanomas and nevi were observed employing both methods, permitting a good discrimination of MLs (diagnostic accuracy = 74.6 and 71.2% for ADAs and RDAs, respectively). Conclusions: Both methods for the automated identification of dark areas are useful for melanoma diagnosis and can be implemented in programs for image analysis. Copyright

The aim of this study was to develop a computerized method for the identification and description of colour areas in melanocytic lesion images based on an approach mimicking the human perception of colours. A colour palette comprising six colour groups (black, dark brown, light brown, blue-grey, red and white) was created by selecting single colour components within melanocytic lesion images acquired using a digital videomicroscope, and was implemented in the image analysis program. For each colour region, the area, the distance from the lesion centroid, the spread, the colour area distribution in the internal and the external part of the lesion, and asymmetries were assessed on 604 melanocytic lesion images in our image database. Black, white and blue-grey colour areas were detected more frequently in melanomas compared with naevi. Moreover, significant differences in colour descriptors were observed for each colour group, showing that colour areas are more unevenly distributed in melanomas compared with naevi. Using a discriminant analysis approach, the extension of dark, white and blue-grey areas and some descriptors of the distribution of the colour areas were identified as the most relevant colour parameters for differentiating between benign and malignant lesions. In conclusion, our automatic procedure breaks down the image into the colour areas used in the clinical examination process, and also supplies a description of their extension and distribution, with parameters that correlate with the clinical concepts of regularity and homogeneity.

Background: Spitz nevus is a benign melanocytic lesion sometimes mistakenly diagnosed clinically as melanoma. Objective: Our aim was to evaluate in vivo reflectance-mode confocal scanning laser microscopy (CSLM) aspects of globular Spitz nevi and to correlate them with those of surface microscopy and histopathology. Methods: A total of 6 Spitz nevi, with globular aspects on epiluminescence observation, were imaged with CSLM and subsequently excised for histopathologic examination. Results: A close correlation among CSLM, epiluminescence, and histopathologic aspects was observed. Individual cells, observed in high-resolution confocal images, were similar in shape and dimension to the histopathologic ones. Lesion architecture was described on reconstructed CSLM images. Melanocytic nests corresponded to globular cellular aggregates at confocal microscopy and to globules at epiluminescence observation. Melanophages were clearly identified in the papillary dermis both by confocal microscopy and histopathology. Conclusion: In vivo CSLM enabled the identification of characteristic cytologic and architectural aspects of Spitz nevi, correlated with histopathology and epiluminescence microscopy observation.

We describe an integrated solution devised for inhouse video surveillance, to control the safety of people living in a domestic environment. The system is composed of robust moving object detection module, able to disregard shadows, a tracking module designed for large occlusion solution and of a posture detector. Shadows, large occlusions and deformable model of people are key features of inhouse surveillance. Moreover, the requirements of high speed reaction to dangerous situations and the need to implement a reliable and low cost televiewing system, led to the introduction of a new multimedia model of semantic transcoding, capable of supporting different user's requests and constraints of their devices (PDA, smart phones, ...). Our application context is the emerging area of domotics (from the Latin word domus that means "home" and informatics) and, in particular, indoor video surveillance of the house where people with some difficulties (elders and disabled people) can now live in a sufficient degree of autonomy, thanks to the strong interaction with the new technologies that can be distributed in the house with affordable costs and high reliability.

In this work, we describe a technique to calibrate images for skin analysis in dermatology. Using a common reference we correct non-uniform illumination effects, give an estimation of the gamma correction and produce a XYZ conversion matrix. The final result is then reverted to a non standard RGB color space, built from the instrument images. In this way different instruments behave uniformly allowing colorimetric characterization, while improving the results of common algorithms. The proposed techniques should be the initial support for a distributed framework where dermatological images can be consistently compared.

Spitz nevi may be often confused with malignant melanoma, because of its rapid growth and alarming clinical features. In vivo confocal reflectance microscopy (CRM) is a novel technique enabling the noninvasive imaging of the skin at a cellular level resolution. Twelve Spitz and 25 melanomas (MMs) were studied by means of CRM (Vivascope 1000, Lucid Inc., USA) and digital dermoscopy (Videocap 200, DS-Mediroup, Italy) for in vivo characterization of cytological and architectural features at CRM, and correlation with dermoscopy and histology. Although large cells with bright cytoplasm and dark eccentric nucleus, sometimes spreading upwards in a pagetoid fashion, were observed both in Spitz nevi and MMs, in the latter case they were more numerous and irregularly shaped. Dermoscopic globules corresponded to cell clusters at CRM and melanocytic nests at histopathology. Spitz nevi frequently presented a peripheral rim of medium sized peripheral clusters, constituted by compact aggregates of large polygonal cells, sometimes observable also on the whole lesion area. In MMs cell clusters were frequently constituted by sparse cells intercalated with thin fibrils giving a multi-lobate appearance or by large confluent aggregates of low reflecting polygonal or elongated cells, resulting in a cerebriform appearance. Although CRM appeared useful for distinction between melanocytic lesions, Spitz nevi presenting numerous atypical cells and dermal-epidermal architecture disarrangement can not be always distinguished from MMs, owing to the limited penetration of the near-infrared laser light, not enabling the evaluation of ‘cell maturation’ with increasing depth.