QC 351 A7 no. 78 / Observers responded to abstract forms (quadrigons) in six experiments, under a signal detection paradigm. Duration of stimulus exposure was shown to have strong effects upon detection accuracy (two studies); immediate feedback of accuracy information to observers affected performance chiefly by influencing guessing bias, not sensitivity (two studies); images that had been blurred and then deblurred by means of an analog device were compared with unblurred originals, and the effects of the retrieval process (deblurring) were characterized quantitatively by a signal detection index (one study); and electroencephalographic correlates of signal detection responses were found to vary with performance accuracy and observer confidence (one study). Discussions of the theory of signal detectability and of electroencephalography, as tools in the study of image quality and of observer sensitivity, are included in the report.

Cette thèse s'inscrit dans le contexte de l'amélioration de la caractérisation de l'occupation du sol à partir d'observations de télédétection de natures très différentes : le radar polarimétrique et les images optiques multispectrales. Le radar polarimétrique permet la détermination de mécanismes de rétrodiffusion provenant de théorèmes de décomposition de l'information polarimétrique utiles à la classification des types d'occupation du sol. Cependant ces décompositions sont peu compréhensibles lorsque que plu- sieurs classes thématiques co-existent dans des proportions très variables au sein des cellules de résolution radar. Le problème est d'autant plus important que le speckle inhérent à l'imagerie radar nécessite l'estimation de ces paramètres sur des voisinages locaux. Nous nous interrogeons alors sur la capacité des données optiques multispectrales sensiblement plus résolues spatialement que le radar polarimétrique à améliorer la compréhension des mécanismes radar. Pour répondre à cette question, nous mettons en place une méthode de démélange des images radar polarimétrique par séparation thématique de sources. L'image optique peut être considérée comme un paramètre de réglage du radar fournissant une vue du mélange. L'idée générale est donc de commencer par un démélange thématique (décomposer l'information radar sur les types d'occupation du sol) avant de réaliser les décompositions polarimétriques (identifier des mécanismes de rétrodiffusion).Dans ce travail nous proposons d'utiliser un modèle linéaire et présentons un algorithme pour réaliser le démélange thématique. Nous déterminons ensuite la capacité de l'algorithme de démé- lange à reconstruire le signal radar observé. Enfin nous évaluons si l'information radar démélangée contient de l'information thématique pertinente. Cette évaluation est réalisée sur des données simulées que nous avons générées et sur des données Radarsat-2 complètement polarimétriques pour un cas d'application de mélange sol nu/forêt. Les résultats montrent que, malgré le speckle, la reconstruction est valable. Il est toujours possible d'estimer localement des bases thématiques permettant de décomposer l'information radar polarimétrique puis de reconstruire le signal observé. Cet algorithme de démélange permet aussi d'assimiler de l'information portée par les images optiques. L'évaluation de la pertinence thématique des bases de la décomposition est plus problématique. Les expériences sur des données simulées montrent que celles-ci représentent bien l'information thématique souhaitée, mais que cette bonne estimation est dépendante de la nature des types thématiques et de leurs proportions de mélange. Cette méthode nécessite donc des études complémentaires sur l'utilisation de méthodes d'estimation plus robustes aux statistiques des images radar. Son application à des images radar de longueur d'onde plus longue pourrait permettre, par exemple, une meilleure estimation du volume de végétation dans le contexte de forêts ouvertes / Land cover is a layer of information of significant interest for land management issues. In this context, combining remote sensing observations of different types is expected to produce more reliable results on land cover classification. The objective of this work is to explore the use of polarimetric radar images in association with co-registered higher resolution optical images. Extracting information from a polarimetric representation consists in decomposing it with target decomposition algorithms. Understanding these mechanisms is challenging as they are mixed inside the radar cell resolution but it is the key to producing a reliable land cover classification. The problem while using these target decomposition algorithms is that average physical parameters are obtained. As a result, each land cover type of a mixed pixel might not be well described by the average polarimetric parameters. The effect is all the more important as speckle affecting radar observations requires a local estimation of the polarimetric matrices. In this context, we chose to assess whether optical images can improve the understanding of radar images at the observation scale so as to retrieve more information. Spatial and spectral unmixing methods, traditionally designed for optical image fusion, were found to be an interesting framework. As a consequence, the idea of unmixing physical radar scattering mechanisms with the optical images is proposed. The original method developed is the decomposition of the polarimetric information, based on land cover type. This thematic decomposition is performed before applying usual target decomposition algorithms. A linear mixing model for radar images and an unmixing algorithm are proposed in this document. Having pointed out that the linear unmixing model is able to split off polarimetric information on a land cover type basis, the information contained in the unmixed matrices is evaluated. The assesment is carried out with generated simulated data and polarimetric radar images from the Radarsat-2 satellite. For this experiment, textit {Bare soil} and textit {Forested area} were considered for land cover types. It was found that despite speckle the reconstructed radar information after the unmixing is statically relevant with the observations. Moreover, the unmixing algorithm is capable of assimilating information from optical images. The question whether the unmixed radar images contain relevant thematic information is more challenging. Results on real and simulated data show that this capacity depends on the types of land cover considered and their respective proportions. Future work will be carried out to make the estimation step more robust to speckle and to test this unmixing algorithm on longer wavelength radar images. In this case, this method could be used to have a better estimation of vegetation biomass in the context of open forested areas

En contexte de changement global, les questions d’adaptation et de pérennisation des systèmes de production sont un enjeu agricole majeur. En Argentine, le 5ème producteur mondial de vins, les conditions thermiques et hydriques sont déjà proches des limites de la culture de la vigne. En tant que culture pérenne, son adaptation à court et moyen termes doit être pensée, dès à présent. La pérennisation de cette culture passe par une adaptation des pratiques culturales. L’objectif de cette thèse visait à proposer des outils de détection et de gestion des pratiques culturales des vignobles à partir d’imagessatellitaires optiques et radar. Une analyse préalable des évolutions du climat et de sa variabilité intrarégionale a mis en évidence les principales menaces et opportunités au regard du changement climatique. A l’échelle locale, le travail sur un grand nombre de parcelles aux caractéristiques hétérogènes a approfondi les connaissances sur l’interaction signal cible en fonction des pratiques culturales. Des cartographies de l’orientation des rangées de vignes, des surfaces protégées par des filets anti-grêles et des modes d’irrigation ont été réalisées afin de dresser un état des lieux du système viticole actuel. Ensuite, l’évaluation du potentiel des données satellitaires pour le suivi de la croissance de la vigne et de ses besoins en eau ont apporté des résultats prometteurs pour le développement d’outils d’aide à la décision pour les viticulteurs. / In the climate change context, the adaptation and sustainability of agricultural systems is a major challenge. In Argentina, the 5th worldwide wine producing country, the thermal and hydrical conditions are already extreme for grapevine production. This perennial crop sustainability depends on the adaptation of cultural practices. The objective of the thesis was to develop tools for helping in cultural pratices management using optical and SAR remote sensing images. First, an analysis of climate evolution and its inner regional variability hilighted the main threats and opportunities in the climate change context. At the local scale, working on a high number of heterogeneous vineyards improved the knowledge about signal and target interaction depending on cultural practices. Maps of row orientation, areas protected by anti-hail nets and irrigation systems were produced for an inventory of the actual viticultural system conditions. Then, the potential of remote sensing data for grapevine growth monitoring and irrigation requirements was evaluated and led to promising preliminary results for developping irrigation monitoring tools destinated to grapevine producers

L'importance de mesurer les paramètres biophysiques de la forêt pour la surveillance de la santé des écosystèmes et la gestion forestière encourage les chercheurs à trouver des méthodes précises et à faible coût en particulier sur les zones étendues et montagneuses. Dans la présente étude, le lidar satellitaire GLAS embarqué à bord du satellite ICESat (Ice Cloud and land Elevation Satellite) a été utilisé pour estimer trois caractéristiques biophysiques des forêts situées dans le nord de l'Iran:1) hauteur maximale de la canopée (Hmax),2)hauteur de Lorey (HLorey), et 3)le volume du bois (V). Des régressions linéaires multiples (RLM), des modèles basés sur les Forêts Aléatoires (FA : Random Forest) et aussi des réseaux de neurones (ANN) ont été développés à l'aide de deux ensembles différents de variables incluant des métriques obtenues à partir des formes d’onde GLAS et des composantes principales (CP) produites à partir de l'analyse en composantes principales (ACP) des données GLAS. Pour valider et comparer les modèles, des critères statistiques ont été calculées sur la base d'une validation croisée. Le meilleur modèle pour l’estimation de la hauteur maximale a été obtenu avec une régression RLM (RMSE=5.0m) qui combine deux métriques extraites des formes d'onde GLAS (H50, Wext), et un paramètre issu du modèle numérique d'élévation (Indice de relief TI). L'erreur moyenne absolue en pourcentage (MAPE) sur les estimations de la hauteur maximale est de 16.4%. Pour la hauteur de Lorey, un modèle basé sur les réseaux de neurones et utilisant des CPs et le Wext fournit le meilleur résultat avec RMSE=3.4m et MAPE=12.3%. Afin d'estimer le volume du bois, deux approches ont été utilisées:(1)estimation du volume à l'aide d’une relation volume-hauteur avec une hauteur estimée à partir de données GLAS et (2)estimation du volume du bois directement à partir des données GLAS en développant des régressions entre le volume in situ et les métriques GLAS. Le résultat de la première approche (RMSE=116.3m3/ha) était légèrement meilleur que ceux obtenus avec la seconde approche. Par exemple, le réseau de neurones basé sur les PCs donnait un RMSE de 119.9m3/ha mais avec des meilleurs résultats que l’approche basée sur la relation volume-hauteur pour les faibles (<10m3/ha) et les forts (>800m3/ha) volumes. Au total, l'erreur relative sur le volume de bois est estimée à environ 26%. En général, les modèles RLM et ANN avaient des meilleures performances par rapport aux modèles de FA. En outre, la précision sur l’estimation de la hauteur à l'aide de métriques issues des formes d'onde GLAS est meilleure que celles basées sur les CPs.Compte tenu des bons résultats obtenus avec les modèles de hauteur GLAS, la production de la carte des hauteurs d’étude par une utilisation combinée de données de télédétection lidar, radar et optique et de données environnementales a été effectuée à l’intérieur de notre zone. Ainsi, des régressions RLM et FA ont été construites entre toutes les hauteurs dérivées des données GLAS, à l'intérieur de la zone d'étude, et les indices extraits des données de télédétection et des paramètres environnementaux. Les meilleurs modèles entrainés pour estimer Hmax (RMSE=7.4m et R_a^2=0.52) et HLorey (RMSE=5.5m et R_a^2=0.59) ont été utilisées pour produire les cartes de hauteurs. La comparaison des Hmax de la carte obtenue avec les valeurs de Hmax in situ à l'endroit de 32 parcelles produit un RMSE de 5.3m et un R2 de 0.71. Une telle comparaison pour HLorey conduit à un RMSE de 4.3m et un R2 de 0.50. Une méthode de régression-krigeage a également été utilisée pour produire une carte des hauteurs en considérant la corrélation spatiale entre les hauteurs. Cette approche, testée dans le but d'améliorer la précision de la carte de la hauteur du couvert fournie par la méthode non-spatiale, a échouée due à l'hétérogénéité de la zone d'étude en termes de la structure forestière et de la topographie. / The importance of measuring forest biophysical parameters for ecosystem health monitoring and forest management encourages researchers to find precise, yet low-cost methods especially in mountainous and large areas. In the present study Geoscience Laser Altimeter System (GLAS) on board ICESat (Ice Cloud and land Elevation Satellite) was used to estimate three biophysical characteristics of forests located in the north of Iran: 1) maximum canopy height (Hmax), 2) Lorey’s height (HLorey), and 3) Forest volume (V). A large number of Multiple Linear Regressions (MLR), Random Forest (RF) and also Artificial Neural Network regressions were developed using two different sets of variables including waveform metrics and Principal Components (PCs) produced from Principal Component Analysis (PCA). To validate and compare models, statistical criteria were calculated based on a five-fold cross validation. Best model concerning the maximum height was an MLR (RMSE=5.0m) which combined two metrics extracted from waveforms (waveform extent "Wext" and height at 50% of waveform energy "H50"), and one from Digital Elevation Model (Terrain Index: TI). The mean absolute percentage error (MAPE) of maximum height estimates was 16.4%. For Lorey’s height, an ANN model using PCs and waveform extent “Wext” outperformed other models (RMSE=3.4m, MAPE=12.3%). In order to estimate forest volume, two approaches was employed: First, estimating volume using volume-height relationship while height is GLAS estimated height; Second, estimation of forest volume directly from GLAS data by developing regressions between in situ volume and GLAS metrics. The result from first approach (116.3m3/ha) was slightly better than the result obtained by the second approach that is a PCs-based ANN model (119.9 m3/ha). But the ANN model performed better in very low (<10 m3/ha) and very high (> 800 m3/ha) volume stands. In total, the relative error of estimated forest volume was about 26%. Generally, MLR and ANN models had better performance when compared to the RF models. In addition, the accuracy of height estimations using waveform metrics was better than those based on PCs.Given the suitable results of GLAS height models (maximum and Lorey’s heights), production of wall to wall height maps from synergy of remote sensing (GLAS, PALSAR, SPOT5 and Landsat-TM) and environmental data (slope, aspect, classified elevation map and also geological map) was taken under consideration. Thus, MLR and RF regressions were built between all GLAS derived heights, inside of the study area, and indices extracted from mentioned remotely sensed and environmental data. The best resulted models for Hmax (RMSE=7.4m and R_a^2=0.52) and HLorey (RMSE=5.5m and R_a^2=0.59) were used to produce a wall to wall maximum canopy height and Lorey’ height maps. Comparison of Hmax extracted from the resulted Hmax map with true height values at the location of 32 in situ plots produced an RMSE and R2 of 5.3m and 0.71, respectively. Such a comparison for HLorey led to an RMSE and R2 of 4.3m and 0.50, respectively. Regression-kriging method was also used to produce canopy height map with considering spatial correlation between canopy heights. This approach, with the aim of improving the precision of canopy height map provided from non-spatial method, was unsuccessful which could be due to the heterogeneity of the study area in case of forest structure and topography.

The newly emerging Stimulated Raman Scattering (SRS) Microscopy has been proved to be a powerful tool in biomedical research. This advanced imaging platform offers high spatiotemporal resolution and chemical specificity, which greatly empowers the label-free biomedical imaging and small molecule metabolite tracing. Throughout the research introduced in this thesis, we focus on the exploration of more applications of SRS microscopy beyond aforementioned. Particularly, this new expedition involves more chemistry and answered two major questions: what SRS can do for chemistry and what chemistry can do for SRS. Chapter 1 introduces the basics of SRS microscopy, such as the physical fundamentals and start-of-art instrumentations. Besides, this chapter discusses the design principles of vibrational reporters through a chemistry view. Chapter 2 introduces one of the major progresses of SRS microscopy beyond biomedical study. We use SRS microscopy to study the ion transportation and concentration polarization phenomena in lithium metal batteries (LMBs), with a strong focus in solid-state polymer electrolyte. A self-induced phase separation process over lithium metal electrode is observed and correlated with local lithium ion concentrations, which inspires a protection mechanism for durable LMB design. Chapter 3 discusses the use of SRS microscopy for in-vivo drug tracing in mammalian cells. A novel alkyne tag is incorporated into bio-engineered natural depsi-peptides and serves as Raman reporter. The mode-of-action of the labeled drug is visualized with SRS microscopy. Chapter 4 heavily focuses on the development of synthetic molecular probes for super-multiplexed optical imaging. We systematically synthesize a library of molecular probes based on 9-cyanopyronin, and their Raman features are characterized to build a model that correlates photophysical properties with structures. The Raman shifts of probes can be tuned with high precision. The multiplexing capability of the new library is demonstrated in labeling fixed and living cell samples.

The purpose of this work was to develop novel optical imaging technology and algorithms as a nondestructive method for detection and diagnosis of cancer in breast specimens. There are many ways in which the diagnosis of disease can benefit from fast and intelligent optical imaging technology. Our existing ability to provide this diagnosis depends on time-consuming pathology analysis. Optical coherence tomography (OCT) is a non-invasive optical imaging modality that provides depth-resolved, high-resolution images of tissue microstructure in real-time. OCT could provide a rapid evaluation of specimens while patients are still in the office, and has strong potential to improve the efficiency in evaluation of breast pathology specimens (biopsy or surgical). In this work, we demonstrate an imaging system to address this unmet clinical need, artificial intelligence algorithms to interpret the images, and early work towards miniaturizing the technology. We present an OCT system that achieves a line scan rate of 250kHz, meaning we can image a pathology cassette in 41 seconds, which is more than double the fastest scan rate in the field. By utilizing a multiplexed superluminescent diode (SLD) light source, which has strong noise performance over imaging speed, we achieve high resolution imaging under 5 um in tissue (axially and laterally). The system features a 1.1 mm 6-dB sensitivity fall-off range when imaging at 250 kHz. The scanner features large-area scanning with the implementation of a 2-axis motorized stage, enabling visualization of areas up to 10 cm x 10 cm (prior work visualizes 3 mm x 3mm). We showcase the results of demonstrating the performance of this system on a 100-patient clinical imaging study of breast biopsies, as well as imaging of clinical pathology specimens from the breast, prostate, lung, and pancreas in an IRB-approved study. Further, we show our work towards developing artificial intelligence (AI) for cancer detection within OCT images. Using retrospective data, we developed a type of AI algorithm known as a convolutional neural network (CNN) to classify OCT images of breast tissue from 49 patients. The binary cancer classification achieved 94% accuracy, 96% sensitivity, and 92% specificity. This framework had higher accuracy than the 88% accuracy of 7 clinician readers combined in our lab’s earlier multi-reader study. Lastly, we demonstrate a supercontinuum light source based on a 1 mm2 Si3N4 photonic chip for OCT imaging that has better performance than the state-of-the-art laser. Existing broadband laser sources for OCT are large, bulky, and have high excess noise. Our Si3N4 chip fundamentally eliminates the excess noise common to lasers and achieves 105 dB sensitivity and 1.81 mm 6-dB sensitivity roll-off with only 300 µW power on the sample.

The dissertation uses the facet model technique to compute the optic flow field directly from a time sequence of image frames. Two techniques, an iterative and a non-iterative one, determine 3D motion parameters and surface structure (relative depth) from the computed optic flow field. Finally we discuss a technique for the image segmentation based on the multi-object motion using both optic flow and its time derivative. The facet model technique computes optic flow locally by solving over-constrained linear equations obtained from a fit over 3D (row, column, and time) neighborhoods in an image sequence. The iterative technique computes motion parameters and surface structure using each to update the other. This technique essentially uses the least square error method on the relationship between optic flow field and rigid body motion. The non-iterative technique computes motion parameters by solving a linear system derived from the relationship between optic flow field and rigid body motion and then computes the relative depth of each pixel using the motion parameters computed. The technique also estimates errors of both the computed motion parameters and the relative depth when the optic flow is perturbed. / Ph. D.

Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 2003. / Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; and the Woods Hole Oceanographic Institution), 2003. / Includes bibliographical references (p. 73-79). / S.M.

QC 351 A7 no. 07 / The Meinel Reducing Camera for the U. S. Naval Observatory's 60-inch telescope, Flagstaff, Arizona, comprises an f /10 collimator designed by Meinel and Wilkerson, and a Leica 50-mm f/2 Summicron camera lens. The collimator consists of a thick, 5-inch field lens located close to the focal plane of the telescope, plus four additional elements extending toward the camera. The collimator has an efl of 10 inches, yielding a 1-inch exit pupil that coincides with the camera's entrance pupil, 1.558 inches beyond the final surface of the collimator. There is room between the facing lenses of the collimator and camera to place filters and a grating. The collimated light here is the best possible situation for interference filters. Problems of the collimator design work included astigmatism due to the stop's being so far outside the collimator, and field curvature. Two computer programs were used in development of the collimator design. Initial work, begun in 1964, was with the University of Rochester's ORDEALS program (this was the first time the authors had used such a program) and was continued through July, 1965. Development subsequently was continued and completed on the Los Alamos Scientific Laboratory's program, LASL. The final design, completed January 24, 1966, was evaluated with ORDEALS. This project gave a good opportunity to compare ORDEALS, an "aberration" program, with LASL, a "ray deviation" program. It was felt that LASL was the superior program in this case, and some experimental runs beginning with flat slabs of glass indicated that it could have been used for the entire development of the collimator. Calculated optical performance of the design indicated that the reducing camera should be "seeing limited" for most work. Some astigmatism was apparent, but the amount did not turn out to be harmful in actual astronomical use. After the final design was arrived at, minor changes were made to accommodate actual glass indices of the final melt, and later to accommodate slight changes of radii and thicknesses of the elements as fabricated. An additional small change in spacing between two of the elements was made at the observatory after the reducing camera had been in use for a short time. The fabricated camera is working according to expectations. Some photographs are included in the report to illustrate its performance and utility.

Orientador: Carlos Lenz Cesar / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-11T10:58:51Z (GMT). No. of bitstreams: 1 Thomaz_AndreAlexandrede_M.pdf: 10062018 bytes, checksum: 1e19c55cb5a4e709c2015e2d90f3ac13 (MD5) Previous issue date: 2007 / Resumo: A pesquisa em fotônica biomedica está claramente tomando a direção do entendimento de processos biológicos a nível celular. A resolução necessária para atingir esse objetivo requer praticamente ferramentas fotônicas. Contudo, uma integração de diferentes ferramentes fotônicas e uma aproximação funcional serão necessárias para acessar os processos biomecânicos e bioquímicos celulares. Deste modo nós podemos observar eventos bioquímicos disparados mecanicamente ou eventos mecânicos disparados bioquimicamente, ou até mesmo observar simultâneamente eventos biomecânicos e bioquímicos disparados por outros meios, entre outros, eletricamente. Uma das grandes vantagens das ferramentas fotônicas é a sua facilidade de integração. Nós desenvolvemos uma ferramenta integrada incorporando pinça óptica simples com Microscopia Confocal "Single-photon" e Multifóton. O sistema consegue realizar microscopias de fluorescência excitada pela absorção de dois fótons e geração de segundo harmônico em conjunto com manipulações ópticas. Medidas de força, elasticidade e viscosidade de membranes esticadas podem ser monitoradas em tempo real pelas microscopias confocais, bem como protozoários capturados opticamente, como, por exemplo, Trypanosoma cruzi. Nós mostraremos vários exemplos do uso de tal ferramenta integrada e seu potencial para observar processos mecânicos e bioquímicos a nível celular / Abstract: The research in biomedical photonics is clearly evolving in the direction of the understanding of biological processes at the cell level. The spatial resolution to accomplish this task practically requires photonics tools. However, an integration of different photonic tools and a multimodal and functional approach will be necessary to access the mechanical and biochemical cell processes. This way we can observe mechanicaly triggered biochemical events or biochemicaly triggered mechanical events, or even observe simultaneously mechanical and biochemical events triggered by other means, e.g. electricaly. One great advantage of the photonic tools is its easiness for integration. Therefore, we developed such integrated tool by incorporating single Optical Tweezers with Confocal Single and Multiphoton Microscopies. This system can perform 2-photon excited fluorescence and Second Harmonic Generation microscopies together with optical manipulations. Force, elasticity and viscosity measurements of stretched membranes can be followed by real time confocal microscopies. Also opticaly trapped living protozoas, such as Trypanosoma cruzi. Integration with CARS microscopy is under way. We will show several examples of the use of such integrated instrument and its potential to observe mechanical and biochemical processes at cell level / Mestrado / Física / Mestre em Física