Adaptive exposure estimation for high dynamic range imaging applied to natural scenes and daylight skies

Digital imaging of natural scenes and optical phenomena present on them (such as shadows, twilights, and crepuscular rays) can be a very challenging task because of the range spanned by the radiances impinging on the capture system. We propose a novel method for estimating the set of exposure times (bracketing set) needed to capture the full dynamic range of a scene with high dynamic range (HDR) content. The proposed method is adaptive to scene content and to any camera response and configuration, and it works on-line since the exposure times are estimated as the capturing process is ongoing. Besides, it requires no a priori information about scene content or radiance values. The resulting bracketing sets are minimal in the default method settings, but the user can set a tolerance for the maximum percentage of pixel population that is underexposed or saturated, which allows for a higher number of shots if a better signal-to-noise ratio (SNR) in the HDR scene is desired. This method is based on the use of the camera response function that is needed for building the HDR radiance map by stitching together several differently exposed low dynamic range images of the scene. The use of HDR imaging techniques converts our digital camera into a tool for measuring the relative radiance outgoing from each point of the scene, and for each color channel. This is important for accurate characterization of optical phenomena present in the atmosphere while not suffering any loss of information due to its HDR.We have compared our method with the most similar one developed so far [IEEE Trans. Image Process. 17, 1864 (2008)]. Results of the experiments carried out for 30 natural scenes show that our proposed method equals or outperforms the previously developed best approach, with less shots and shorter exposure times, thereby asserting the advantage of being adaptive to scene content for exposure time estimation. As we can also tune the balance between capturing time and the SNR in our method, we have compared its SNR performance against that of Barakat’s method as well as against a ground-truth HDR image of maximum SNR. Results confirm the success of the proposed method in exploiting its tunability to achieve the desired balance of total Δt and SNR

Medición de los niveles de actividad física en personas con discapacidad física mediante acelerometría y cuestionario

Objetivo: Analizar la relación entre el nivel de actividad física registrada y el percibido en población con discapacidad física mediante acelerometría y cuestionario, así como estudiar las diferencias evaluadas con ambos instrumentos según nivel de actividad física personal y otras variables como el género o uso de la silla de ruedas. Metodología: La muestra la componen 37 sujetos con discapacidad física (28 hombres y 9 mujeres), con una edad media de 38 ±10,9 años. Se dividió a la muestra en tres grupos en función del número de horas de actividad física semanal: sedentarios (S, n = 8), practicantes habituales (PH, n = 13) y practicantes de alto rendimiento (AR, n = 16). Los sujetos llevaron un monitor metabólico de actividad física SenseWear Pro Armband (SWA) durante siete días, las 24 horas. Una vez retirado, se administró el cuestionario Physical Activity Scale for Individuals with Physical Disabilities (Escala de Actividad Física para Personas con Discapacidades Físicas) para medir la actividad física percibida, recogiéndose también datos antropo-métricos y personales. Resultados: La correlación de Pearson (n = 37) mostró relación entre el PASIPD y las variables METS promedio (r=0,52; p<0,01), gasto energético en activo (r=0,35; p<0,05) y duración de la actividad física (r=0,53; p<0,01). El PASIPD (en MET hr/día) arrojó los siguientes valores según grupo: S 8,55 ±4,35; PH 12,99 ±5,88; AR 27,41 ±19,66. Según grupos, el SWA registró, entre otras variables, los METs promedio (S 1,35 ±0,26; PH 1,46 ±0,19; AR 1,70 ±0,18) y la duración de la actividad física (S 10:33:07 ±07:47:42; PH 12:59:32 ±07:21:38; AR 22:22:26 ±07:58:58). El ANOVA mostró diferencias (p<0,05) entre grupos para el PASIPD y las citadas variables del SWA. Conclusiones: Este estudio confirma la idoneidad de utilizar de forma combinada un cuestionario y un monitor metabólico de actividad física en población con discapacidad física para la evaluación del nivel de actividad física en esta població

Combining transverse field detectors and color filter arrays to improve multispectral imaging systems

This work focuses on the improvement of a multispectral imaging sensor based on transverse field detectors (TFDs). We aimed to achieve a higher color and spectral accuracy in the estimation of spectral reflectances from sensor responses. Such an improvement was done by combining these recently developed silicon-based sensors with color filter arrays (CFAs). Consequently, we sacrificed the filter-less full spatial resolution property of TFDs to narrow down the spectrally broad sensitivities of these sensors.We designed and performed several experiments to test the influence of different design features on the estimation quality (type of sensor, tunability, interleaved polarization, use of CFAs, type of CFAs, number of shots), some of which are exclusive to TFDs.We compared systems that use a TFD with systems that use normal monochrome sensors, both combined with multispectral CFAs as well as common RGB filters present in commercial digital color cameras. Results showed that a system that combines TFDs and CFAs performs better than systems with the same type of multispectral CFA and other sensors, or even the same TFDs combined with different kinds of filters used in common imaging systems. We propose CFA+TFD-based systems with one or two shots, depending on the possibility of using longer capturing times or not. Improved TFD systems thus emerge as an interesting possibility for multispectral acquisition, which overcomes the limited accuracy found in previous studies.Spanish Ministry of Economy and Competitiveness through the research project DPI2011-2320

The extent of aortic lymphadenectomy in locally advanced cervical cancer impacts on survival

Cáncer de cuello de útero; Supervivencia libre de enfermedad; Metástasis linfáticaCàncer de coll de l'úter; Supervivència lliure de malaltia; Metàstasi limfàticaCervical Cancer; Disease-Free Survival; Lymphatic MetastasisObjective The prognostic impact of surgical paraaortic staging remains unclear in patients with locally advanced cervical cancer (LACC). The objective of our study was to evaluate the results of the surgical technique of preoperative aortic lymphadenectomy in LACC related to tumor burden and disease spread to assess its influence on survival. Methods Data of 1,072 patients with cervical cancer were taken from 11 Spanish hospitals (Spain-Gynecologic Oncology Group [GOG] working group). Complete aortic lymphadenectomy surgery (CALS) was considered when the lymph nodes (LNs) were excised up to the left renal vein. The extent of the disease was performed evaluating the LNs by calculating the geometric means and quantifying the log odds between positive LNs and negative LNs. The Kaplan-Meier method was used to estimate the survival distribution. A Cox proportional hazards model was used to account for the influence of multiple variables. Results A total of 394 patients were included. Pathological analysis revealed positive aortic LNs in 119 patients (30%). LODDS cut-off value of −2 was established as a prognostic indicator. CALS and LODDS <−2 were associated with better disease free survival and overall survival than suboptimal aortic lymphadenectomy surgery and LODDS ≥−2. In a multivariate model analysis, CALS is revealed as an independent prognostic factor in LACC. Conclusion When performing preoperative surgical staging in LACC, it is not advisable to take simple samples from the regional nodes. Radical dissection of the aortic and pelvic regions offers a more reliable staging of the LNs and has a favorable influence on survival

Brain MRI study for glioma segmentation using convolutional neural networks and original post-processing techniques with low computational demand

Gliomas are brain tumors composed of different highly heterogeneous histological subregions. Image analysis techniques to identify relevant tumor substructures have high potential for improving patient diagnosis, treatment and prognosis. However, due to the high heterogeneity of gliomas, the segmentation task is currently a major challenge in the field of medical image analysis. In the present work, the database of the Brain Tumor Segmentation (BraTS) Challenge 2018, composed of multimodal MRI scans of gliomas, was studied. A segmentation methodology based on the design and application of convolutional neural networks (CNNs) combined with original post-processing techniques with low computational demand was proposed. The post-processing techniques were the main responsible for the results obtained in the segmentations. The segmented regions were the whole tumor, the tumor core, and the enhancing tumor core, obtaining averaged Dice coefficients equal to 0.8934, 0.8376, and 0.8113, respectively. These results reached the state of the art in glioma segmentation determined by the winners of the challenge.Comment: 34 pages, 12 tables, 23 figure

TET2 overexpression in chronic lymphocytic leukemia is unrelated to the presence of TET2 variations

This is an open access article distributed under the Creative Commons Attribution License.TET2 is involved in a variety of hematopoietic malignancies, mainly in myeloid malignancies. Most mutations of TET2 have been identified in myeloid disorders, but some have also recently been described in mature lymphoid neoplasms. In contrast to the large amount of data about mutations of TET2, some data are available for gene expression. Moreover, the role of TET2 in chronic lymphocytic leukemia (CLL) is unknown. This study analyzes both TET2 expression and mutations in 48 CLL patients. TET2 expression was analyzed by exon arrays and quantitative real-time polymerase chain reaction (qRT-PCR). Next-generation sequencing (NGS) technology was applied to investigate the presence of TET2 variations. Overexpression of TET2 was observed in B-cell lymphocytes from CLL patients compared with healthy donors (P = 0.004). In addition, in CLL patients, an overexpression of TET2 was also observed in the clonal B cells compared with the nontumoral cells (P = 0.002). However, no novel mutations were observed. Therefore, overexpression of TET2 in CLL seems to be unrelated to the presence of genomic TET2 variations.This work was partially supported by Grants from the Spanish Fondo de Investigaciones Sanitarias FIS 09/01543, PI12/00281, Proyectos de Investigacion del SACYL 355/A/09, COST Action “EuGESMA” (BM0801), Fundación “Manuel Solorzano,” Obra Social Banca Cívica (Caja Burgos), Fundacion Española de Hematología y Hemoterapia (FEHH), and by a Grant (RD12/0036/0069) from Red Temática de Investigación Cooperativa en Cáncer (RTICC), Instituto de Salud Carlos III (ISCIII), Spanish Ministry of Economy and Competitiveness and European Regional Development Fund (ERDF) “Una manera de hacer Europa”, and NGS-PTL no. 306242. Maríıa Hernandez-Sánchez is fully suported by an “Ayuda predoctoral de la Junta de Castilla y Leon” by the “Fondo Social Europeo.”Peer Reviewe

The extent of aortic lymphadenectomy in locally advanced cervical cancer impacts on survival

The prognostic impact of surgical paraaortic staging remains unclear in patients with locally advanced cervical cancer (LACC). The objective of our study was to evaluate the results of the surgical technique of preoperative aortic lymphadenectomy in LACC related to tumor burden and disease spread to assess its influence on survival. Data of 1,072 patients with cervical cancer were taken from 11 Spanish hospitals (Spain-Gynecologic Oncology Group [GOG] working group). Complete aortic lymphadenectomy surgery (CALS) was considered when the lymph nodes (LNs) were excised up to the left renal vein. The extent of the disease was performed evaluating the LNs by calculating the geometric means and quantifying the log odds between positive LNs and negative LNs. The Kaplan-Meier method was used to estimate the survival distribution. A Cox proportional hazards model was used to account for the influence of multiple variables. A total of 394 patients were included. Pathological analysis revealed positive aortic LNs in 119 patients (30%). LODDS cut-off value of −2 was established as a prognostic indicator. CALS and LODDS <−2 were associated with better disease free survival and overall survival than suboptimal aortic lymphadenectomy surgery and LODDS ≥−2. In a multivariate model analysis, CALS is revealed as an independent prognostic factor in LACC. When performing preoperative surgical staging in LACC, it is not advisable to take simple samples from the regional nodes. Radical dissection of the aortic and pelvic regions offers a more reliable staging of the LNs and has a favorable influence on survival

TET2

TET2 is involved in a variety of hematopoietic malignancies, mainly in myeloid malignancies. Most mutations of TET2 have been identified in myeloid disorders, but some have also recently been described in mature lymphoid neoplasms. In contrast to the large amount of data about mutations of TET2, some data are available for gene expression. Moreover, the role of TET2 in chronic lymphocytic leukemia (CLL) is unknown. This study analyzes both TET2 expression and mutations in 48 CLL patients. TET2 expression was analyzed by exon arrays and quantitative real-time polymerase chain reaction (qRT-PCR). Next-generation sequencing (NGS) technology was applied to investigate the presence of TET2 variations. Overexpression of TET2 was observed in B-cell lymphocytes from CLL patients compared with healthy donors (P = 0.004). In addition, in CLL patients, an overexpression of TET2 was also observed in the clonal B cells compared with the nontumoral cells (P = 0.002). However, no novel mutations were observed. Therefore, overexpression of TET2 in CLL seems to be unrelated to the presence of genomic TET2 variations

Automated low-cost device to produce sub-micrometric polymer fibers based on blow spun method

Attending the latest advances in polymeric fibers, the design of low-cost, and high-quality scientific equipment for obtaining fibers seemed essential. To overcome this challenge, a 3D printable prototype was designed, assembled, and validated to obtain fibers using the SBS method. The particular configuration of the prototype consisted of controlling the process conditions such as working distance and injection flow, as well as other parameters such as RPM and the axial movement of the cylindrical collector. Thus, these parameters were automated using a microcontroller (Arduino) that receives information from an Android device with bluetooth connectivity to control each of the elements of the equipment. Subsequently, the repeatability and reproducibility of the fibers was verified using polymers such as polystyrene (PS), polysulfone (PSF) and polyethylene oxide (PEO); furthermore, PSF fibers were manufactured to analyze the influence of working distance and the axial movement of the collector on their production.Fondos de Investigación de Fco. Javier González Benito, política de reinversión de costes generales, Universidad Carlos III de Madrid [2012/00130/004] and Acción Estratégica en Materiales Compuestos Poliméricos e Interfases, Universidad Carlos III de Madrid [2011/00287/002]. Besides, authors greatly appreciate the Consejo Nacional de Ciencia y Tecnología (CONACyT- México) for financial support associated to the scholarship number 625396

Band selection pipeline for maturity stage classification in bell peppers: From full spectrum to simulated camera data

This paper describes a workflow for classifying the maturity of bell peppers using hyperspectral imaging and machine learning. The approach involves using spectral reflectance to determine the number of maturity stages, followed by a classification task using the optimal bands for accurate classification. The study explores a realistic scenario using simulated camera responses and investigates the use of real sensors with their spectral sensitivities and noise. Four classifier algorithms (RBFNN, PLS-DA, SVM, and LDA) were employed to predict the maturity stage based on spectral reflectance. The best results were achieved with the LDA algorithm, which was used in the optimization process for band selection. The optimized bands in the VISNIR range (400–1000 nm) were found to be [783.5, 844.1, and 905.4] nm, with an accuracy of 90.67% for spectral data. For camera responses with intermediate-level noise, the best bands were [760, 820, and 900 nm], achieving an accuracy of 81%. Overall, using three bands yielded satisfactory and practical results for real-world implementation.Universidad de Granada/CBU