A New Framework for Quality Assessment of High-Resolution Fingerprint Images.

The quality assessment of sets of features extracted from patterns of epidermal ridges on our fingers is a biometric challenge problem with implications on questions concerning security, privacy and identity fraud. In this work, we introduced a new methodology to analyze the quality of high-resolution fingerprint images containing sets of fingerprint pores. Our approach takes into account the spatial interrelationship between the considered features and some basic transformations involving point process and anisotropic analysis. We proposed two new quality index algorithms following spatial and structural classes of analysis. These algorithms have proved to be effective as a performance predictor and as a filter excluding low-quality features in a recognition process. The experiments using error reject curves show that the proposed approaches outperform the state-of-the-art quality assessment algorithm for high-resolution fingerprint recognition, besides defining a new method for reconstructing their friction ridge phases in a very consistent way.

Measuring handball players trajectories using an automatically trained boosting algorithm.

The aim of the present paper is to propose and evaluate an automatically trained cascaded boosting detector algorithm based on morphological segmentation for tracking handball players. The proposed method was able to detect correctly 84% of players when applied to the second period of that same game used for training and 74% when applied to a different game. Furthermore, the analysis of the automatic training using boosting detector revealed general results such as the training time initially increased with the number of figures used, but as more figures were added, the training time decreased. Automatic morphological segmentation has shown to be a fast and efficient method for selecting image regions for the boosting detector and allowed an improvement in the automatic tracking of handball players.

[Contribution of nuclear texture analysis for the differential diagnosis of follicular lesions of the thyroid: comparison to immunohistochemical markers]. / Contribuição da análise de textura do núcleo celular para o diagnóstico diferencial de lesões foliculares da tireoide: comparação com marcadores imunoistoquímicos.

OBJECTIVE AND METHODS: To investigate the utility of nuclear chromatin texture assessment in the differential diagnosis of follicular patterned lesions, by means of examining 76 samples previously submitted to the immunohistochemical protein analysis of HBME-1, CK-19 and galectina-3. RESULTS: HBME-1 confirmed to be the most sensitive marker of malignancy. A series of morphometric, densitometric and texture variables were useful in the discrimination of the different types of follicular lesions. Among these variables, r(2), a parameter related to the granularity of the nucleus presented the best accuracy, sensitivity, specificity and positive and negative predictive values, distinguishing benign from malignant lesions. CONCLUSION: The morphometric analysis of nuclear chromatin images may add accuracy to the differential diagnosis of follicular patterned lesions.

Contribuição da análise de textura do núcleo celular para o diagnóstico diferencial de lesões foliculares da tireoide: comparação com marcadores imunoistoquímicos / Contribution of nuclear texture analysis for the differential diagnosis of follicular lesions of the thyroid: comparison to immunohistochemical markers

OBJETIVO E MÉTODOS: Com o propósito de investigar a contribuição do exame da cromatina nuclear no diagnóstico diferencial das lesões foliculares da glândula tireoide, foram estudadas 76 amostras previamente submetidas à análise de expressão proteica de HBME-1, CK-19 e galectina-3. RESULTADOS: HBME-1 confirmou-se como o mais sensível marcador imunoistoquímico de malignidade. Uma série de variáveis morfométricas, densitométricas e de textura foram úteis na distinção entre os diferentes tipos de lesão folicular. Entre essas variáveis, o r², parâmetro relacionado à granularidade do núcleo, apresentou a melhor acurácia, sensibilidade, especificidade, valor preditivo positivo e negativo, diferenciando lesões benignas de malignas. CONCLUSÃO: A morfometria analítica de imagem da cromatina nuclear pode acrescentar acurácia ao diagnóstico diferencial das lesões de padrão folicular.

OBJECTIVE AND METHODS: To investigate the utility of nuclear chromatin texture assessment in the differential diagnosis of follicular patterned lesions, by means of examining 76 samples previously submitted to the immunohistochemical protein analysis of HBME-1, CK-19 and galectina-3. RESULTS: HBME-1 confirmed to be the most sensitive marker of malignancy. A series of morphometric, densitometric and texture variables were useful in the discrimination of the different types of follicular lesions. Among these variables, r², a parameter related to the granularity of the nucleus presented the best accuracy, sensitivity, specificity and positive and negative predictive values, distinguishing benign from malignant lesions. CONCLUSION: The morphometric analysis of nuclear chromatin images may add accuracy to the differential diagnosis of follicular patterned lesions.

Image preprocessing improves Fourier-based texture analysis of nuclear chromatin.

OBJECTIVE: To investigate whether preprocessing of digitized images can improve the image analysis of chromatin of cytologic preparations using Fast Fourier Transformation (FFT). STUDY DESIGN: In a preprocessing step the nuclear borders of the segmented nuclei were smoothed, thus avoiding the Airy ring artifact. We tested this method, comparing the inertia values of digitalized cardiomyocyte nuclei of rats of different ages. Furthermore, we created in silicio nuclear images with chromatin alterations at or nearby the nuclear edge in order to investigate the robustness of our method. RESULTS: After preprocessing, the FFT-derived variable inertia discriminated significantly better the chromatin structure of the nuclei at different ages in every frequency range. The investigation on simulated nuclei revealed that within the frequency ranges from 1.8 microm to 0.72 microm smoothing of the borders does not interfere with the detection of chromatin changes at the nuclear border. CONCLUSION: Smoothing of borders in segmented images can improve the analysis of Fourier-derived variables of the chromatin texture.

Shannon's entropy and fractal dimension provide an objective account of bone tissue organization during calvarial bone regeneration.

The regeneration of compact bone involves the deposition of a poorly organized connective tissue template that remodels into compact lamellar bone. An objective description of this process is difficult because classical histomorphometry is unable to correctly characterize qualitative changes in tissue complexity. In this study, we demonstrated the use of two distinct methods of image texture analysis, the Shannon's entropy [standard error (SE)], and the fractal dimension (FD) to characterize the formation and remodeling of newly formed compact bone within two different polyanionic collagen-elastin matrices. The matrices were implanted in defects created into parietal bones of rats. The SE and FD were calculated for histological images of the experimental groups collected 3, 7, 15, 30, 60, and 365 days postsurgery and for the original bone only at day 365. Results showed that the SE and the FD initially increased and then diminished for all groups from day 3 to day 365 approaching the values of the original bone. These results are consistent with poor tissue organization during early osteogenesis that remodels into an organized lamellar structure, showing that these methods can be valuable tools to describe bone tissue remodeling during the regeneration process of compact bones.

Analysis of the distances covered by first division brazilian soccer players obtained with an automatic tracking method.

Methods based on visual estimation still is the most widely used analysis of the distances that is covered by soccer players during matches, and most description available in the literature were obtained using such an approach. Recently, systems based on computer vision techniques have appeared and the very first results are available for comparisons. The aim of the present study was to analyse the distances covered by Brazilian soccer players and compare the results to the European players', both data measured by automatic tracking system. Four regular Brazilian First Division Championship matches between different teams were filmed. Applying a previously developed automatic tracking system (DVideo, Campinas, Brazil), the results of 55 outline players participated in the whole game (n = 55) are presented. The results of mean distances covered, standard deviations (s) and coefficient of variation (cv) after 90 minutes were 10,012 m, s = 1,024 m and cv = 10.2%, respectively. The results of three-way ANOVA according to playing positions, showed that the distances covered by external defender (10642 ± 663 m), central midfielders (10476 ± 702 m) and external midfielders (10598 ± 890 m) were greater than forwards (9612 ± 772 m) and forwards covered greater distances than central defenders (9029 ± 860 m). The greater distances were covered in standing, walking, or jogging, 5537 ± 263 m, followed by moderate-speed running, 1731 ± 399 m; low speed running, 1615 ± 351 m; high-speed running, 691 ± 190 m and sprinting, 437 ± 171 m. Mean distance covered in the first half was 5,173 m (s = 394 m, cv = 7.6%) highly significant greater (p < 0.001) than the mean value 4,808 m (s = 375 m, cv = 7.8%) in the second half. A minute-by-minute analysis revealed that after eight minutes of the second half, player performance has already decreased and this reduction is maintained throughout the second half. Key pointsA novel automatic tracking method was presented. No previous work was found in the literature reporting data of simultaneous trajectories of all soccer players obtained by an automatic tracking method.The study reveals 7% reduction in mean distance covered in the second half and moreover after eight minutes of the second half, player performance has already decreased and this reduction is maintained throughout the second half.

Texture analysis of the epidermis based on fast Fourier transformation in Sjögren-Larsson syndrome.

OBJECTIVE: To investigate whether image analysis of routine hematoxylin-eosin (H-E) skin sections using fast Fourier transformation (FFT) could detect structural alterations in patients with Sjögren-Larsson syndrome (SLS) diagnosed by molecular biology. STUDY DESIGN: Skin punch biopsies of 9 patients with SLS and 17 healthy volunteers were obtained. Digital images of routine histologic sections were taken, and their gray scale luminance was analyzed by FFT. The inertia values were determined for different ranges of the spatial frequencies in the vertical and horizontal direction. To get an estimation of anisotropy, we calculated the resultant vector of the designated frequency ranges. RESULTS: In the prickle cell layer, SLS patients showed more intense amplitudes in spatial structures with periods between 1.2 and 3.6 microm in the vertical direction, which correlated in part with accentuated nuclei and nucleoli and perinucleolar halos in the H-E sections. In a linear discriminant analysis, the variables derived from the FFT images correctly discriminated 84.6% of the patients. Texture features derived from the gray level cooccurrence matrix were not able to separate the groups. CONCLUSION: Exploratory texture analysis by FFT was able to detect discrete alterations in the prickle cell layer in routine light microscopy slides of SLS patients. The structural changes identified by FFT may be related to abnormal cellular components associated with aberrant lipid metabolism.

Biomineralization of polyanionic collagen-elastin matrices during cavarial bone repair.

The polyanionic collagen-elastin matrices (PCEMs) are osteoconductive scaffolds that present high biocompatibility and efficacy in the regeneration of bone defects. In this study, the objective was to determine if these matrices are directly mineralized during the osteogenesis process and their influence in the organization of the new bone extracellular matrix. Samples of three PCEMs, differing in their charge density, were implanted into critical-sized calvarial bone defects created in rats and evaluated from 3 days up to 1 year after implantation. The implanted PCEMs were directly biomineralized by osteoblasts as shown by ultrastructural, histoenzymologic, and morphologic analysis. The removal of the implants occurred during the bone remodeling process. The organization of the new bone matrix was evaluated by image texture analysis determining the Shannon's entropy and the fractal dimension of digital images. The bone matrix complexity decreased as the osteogenesis progressed approaching the values obtained for the original bone structure. These results show that the PCEMs allow faster formation of new bone by direct biomineralization of its structure and skipping the biomaterial resorption phase.

The fractal dimension of nuclear chromatin as a prognostic factor in acute precursor B lymphoblastic leukemia.

The fractal nature of the DNA arrangement has been postulated to be a common feature of all cell nuclei. We investigated the prognostic importance of the fractal dimension (FD) of chromatin in blasts of patients with acute precursor B lymphoblastic leukemia (B-ALL). In 28 patients, gray scale transformed pseudo-3D images of 100 nuclei (May-Grünwald-Giemsa stained bone marrow smears) were analyzed. FD was determined by the Minkowski-Bouligand method extended to three dimensions. Goodness-of-fit of FD was estimated by the R2 values in the log-log plots. Whereas FD presented no prognostic relevance, patients with higher R2 values showed a prolonged survival. White blood cell count (WBC), age and mean fluorescence intensity of CD45 (MFICD45) were all unfavorable prognostic factors in univariate analyses. In a multivariate Cox-regression, R2, WBC, and MFICD45, entered the final model, which showed to be stable in a bootstrap resampling study. Blasts with lower R2 values, equivalent to accentuated "coarseness" of the chromatin pattern, which may reflect profound changes of the DNA methylation, indicated a poor prognosis. In conclusion the goodness-of-fit of the Minkowski-Bouligand dimension of chromatin can be regarded as a new and biologically relevant prognostic factor for patients with B-ALL.

A flexible software for tracking of markers used in human motion analysis.

In this work, we present a software for the tracking of markers used in human motion analysis. This software is based mainly on image sequences captured by video cameras and on image processing and computer vision tools. Unlike the optoelectronic systems, which record only the coordinates of the markers, a video-based system offers more visual information and flexibility which can be exploited in different applications. However, it needs a more complex tracking procedure concerned with the extraction and identification of the used markers. The tracking module presented here is divided into the following three procedures: segmentation, matching and prediction. The segmentation consists in extracting the objects of interest (markers). The matching is used to find the correspondence between the extracted objects in two consecutive frames. The prediction is important to limit the region of processing, thus reducing the execution time. Some results of the automatic tracking are presented together with their application in human motions analysis.