13 research outputs found

    Development Of Contrast Enhancement Method For Digital Images

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    Photos captured in the dark environments, which have insufficient or uneven lighting conditions, might lead to low contrast images. The night images are looked dark and not clear as compared to day images. Image enhancement methods can be applied to improve the image quality. Histogram equalization (HE) method is a common image enhancement method. Although researchers had proposed many enhancement methods which including global and local histogram equalization, there are still some problems faced which include over enhancement, shift of mean brightness and loss of details. Hence, two image enhancement methods were developed by cascading exposure sub-image histogram equalization (ESIHE) and contrast limited adaptive histogram equalization (CLAHE) in different sequences. ESIHE is a global histogram equalization based method, while CLAHE is a local histogram equalization based method. Then, these two proposed methods were compared with existing HE based methods qualitatively and quantitatively. The qualitative assessment is visual assessment survey, while quantitative assessments are. noise standard deviation (NSD), image variance (IV), speckle index (SI) and contrast per pixel (CPP). Based on the assessments, the method that applied ESIHE then followed by CLAHE is able to enhance images better than the method applied CLAHE first and followed by ESIHE. The output image have a natural appearance, high contrast, and the details of image are clear

    Shape and Level Bottles Detection Using Local Standard Deviation and Hough Transform

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    This paper presents shape and level analysis using local standard deviation and Hough transform technique to detect the shape and level of the bottle.A 155 sample images are used as a test product to detect shape and level. Local standard deviation is used contrast gain technique to segment the shape of the bottle by enhancing the contrast of the image. The ratio of the area is calculated from the extent parameter. The maximum and minimum water level is created by using Hough transform technique to identify the level of the water. Decision tree is applied to classify the shape and level of the bottle either good or defect condition. From experimental result, 97% and 93% accuracy of shape and level is achieved which shows that the proposed analysis technique is potential to be applied for beverages product inspection system

    Detail and contrast enhancement in images using dithering and fusion

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    This thesis focuses on two applications of wavelet transforms to achieve image enhancement. One of the applications is image fusion and the other one is image dithering. Firstly, to improve the quality of a fused image, an image fusion technique based on transform domain has been proposed as a part of this research. The proposed fusion technique has also been extended to reduce temporal redundancy associated with the processing. Experimental results show better performance of the proposed methods over other methods. In addition, achievements have been made in terms of enhancing image contrast, capturing more image details and efficiency in processing time when compared to existing methods. Secondly, of all the present image dithering methods, error diffusion-based dithering is the most widely used and explored. Error diffusion, despite its great success, has been lacking in image enhancement aspects because of the softening effects caused by this method. To compensate for the softening effects, wavelet-based dithering was introduced. Although wavelet-based dithering worked well in removing the softening effects, as the method is based on discrete wavelet transform, it lacked in aspects like poor directionality and shift invariance, which are responsible for making the resultant images look sharp and crisp. Hence, a new method named complex wavelet-based dithering has been introduced as part of this research to compensate for the softening effects. Image processed by the proposed method emphasises more on details and exhibits better contrast characteristics in comparison to the existing methods

    Modelo de sistema de soporte a la diagnosis de trastornos osteoarticulares de miembros inferiores utilizando procesamiento de imágenes de rayos X

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    Los trastornos osteoarticulares aquejan a personas de todas las regiones del mundo sin distinción, ejemplos de ellas son: la osteoporosis y atrosis. La OMS determina la existencia de un incremento de casos en sociedades socioeconómicas más bajas y la Unión Europea establece una estrategia enfocada a entregar salud personalizada en el momento correcto, y brindar una alternativa de prevención oportuna y especifica denominada (PerMed). En este contexto nuestro país necesita aplicar la Medicina Personalizada para diagnosticar a tiempo enfermedades con alta incidencia. La presente investigación busca alinearse a los objetivos de la Medicina Personalizada proporcionando un modelo de sistema de soporte a la diagnosis de trastornos osteoarticulares de miembros inferiores utilizando procesamiento de imágenes de rayos X, teniendo presente la confidencialidad y protección de los datos. El pre-procesamiento de las imágenes de rayos X, permitió eliminar los desafíos de estas imágenes, y posibilito la generación de un gold-standard que sirvió como guía para la segmentación-registro de las estructuras óseas de miembros inferiores. Se utilizaron los modelos estadísticos como: SSM - Statistical Shape Model, SAM – Statistical Appeareance Model, ASM - Active Shape Model y Gradient Profiling en el refinamiento de la etapa de segmentación-registro como parte del entrenamiento y prueba. Estos modelos han sido validados con artículos de investigación presentados en el Capítulo IV con resultados de precisión en la segmentación entre el 74 % y 83 % y para la clasificación de las estructuras óseas dependiendo del objetivo a resolver sea: a) detectar fracturas en el acetábulo, o b) detectar osteoporosis en el fémur proximal, los resultados obtuvieron una precisión de: 73% y 87% respectivamente; y por ultimo para lograr el objetivo de: c) medir la distancia articular, se obtiene un error promedio equivalente a 2.4 px, este es un error aceptable para respaldar el diagnostico de desgaste articular de cadera llamado "osteoartritis de cadera". Asimismo, hubo una mejora significativa en el tiempo de procesamiento comparado con la literatura analizada

    The Role of Transient Vibration of the Skull on Concussion

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    Concussion is a traumatic brain injury usually caused by a direct or indirect blow to the head that affects brain function. The maximum mechanical impedance of the brain tissue occurs at 450±50 Hz and may be affected by the skull resonant frequencies. After an impact to the head, vibration resonance of the skull damages the underlying cortex. The skull deforms and vibrates, like a bell for 3 to 5 milliseconds, bruising the cortex. Furthermore, the deceleration forces the frontal and temporal cortex against the skull, eliminating a layer of cerebrospinal fluid. When the skull vibrates, the force spreads directly to the cortex, with no layer of cerebrospinal fluid to reflect the wave or cushion its force. To date, there is few researches investigating the effect of transient vibration of the skull. Therefore, the overall goal of the proposed research is to gain better understanding of the role of transient vibration of the skull on concussion. This goal will be achieved by addressing three research objectives. First, a MRI skull and brain segmentation automatic technique is developed. Due to bones’ weak magnetic resonance signal, MRI scans struggle with differentiating bone tissue from other structures. One of the most important components for a successful segmentation is high-quality ground truth labels. Therefore, we introduce a deep learning framework for skull segmentation purpose where the ground truth labels are created from CT imaging using the standard tessellation language (STL). Furthermore, the brain region will be important for a future work, thus, we explore a new initialization concept of the convolutional neural network (CNN) by orthogonal moments to improve brain segmentation in MRI. Second, the creation of a novel 2D and 3D Automatic Method to Align the Facial Skeleton is introduced. An important aspect for further impact analysis is the ability to precisely simulate the same point of impact on multiple bone models. To perform this task, the skull must be precisely aligned in all anatomical planes. Therefore, we introduce a 2D/3D technique to align the facial skeleton that was initially developed for automatically calculating the craniofacial symmetry midline. In the 2D version, the entire concept of using cephalometric landmarks and manual image grid alignment to construct the training dataset was introduced. Then, this concept was extended to a 3D version where coronal and transverse planes are aligned using CNN approach. As the alignment in the sagittal plane is still undefined, a new alignment based on these techniques will be created to align the sagittal plane using Frankfort plane as a framework. Finally, the resonant frequencies of multiple skulls are assessed to determine how the skull resonant frequency vibrations propagate into the brain tissue. After applying material properties and mesh to the skull, modal analysis is performed to assess the skull natural frequencies. Finally, theories will be raised regarding the relation between the skull geometry, such as shape and thickness, and vibration with brain tissue injury, which may result in concussive injury

    Modelling facial dynamics change as people age

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    In the recent years, increased research activity in the area of facial ageing modelling has been recorded. This interest is attributed to the potential of using facial ageing modelling techniques for a number of different applications, including age estimation, prediction of the current appearance of missing persons, age-specific human-computer interaction, computer graphics, forensic applications, and medical applications. This thesis describes a general AAM model for modelling 4D (3D dynamic) ageing and specific models to map facial dynamics as people age. A fully automatic and robust pre-processing pipeline is used, along with an approach for tracking and inter-subject registering of 3D sequences (4D data). A 4D database of 3D videos of individuals has been assembled to achieve this goal. The database is the first of its kind in the world. Various techniques were deployed to build this database to overcome problems due to noise and missing data. A two-factor (age groups and gender) analysis of variance (MANOVA) was performed on the dataset. The groups were then compared to assess the separate effects of age on gender through variance analysis. The results show that smiles alter with age and have different characteristics between males and females. We analysed the rich sources of information present in the 3D dynamic features of smiles to provide more insight into the patterns of smile dynamics. The sources of temporal information that have been investigated include the varying dynamics of lip movements, which are analysed to extract the descriptive features. We evaluated the dynamic features of closed-mouth smiles among 80 subjects of both genders. Multilevel Principal Components Analysis (mPCA) is used to analyse the effect of naturally occurring groups in a population of individuals for smile dynamics data. A concise overview of the formal aspects of mPCA has been outlined, and we have demonstrated that mPCA offers a way to model the variations at different levels of structure in the data (between and within group levels)

    Exploring Animal Behavior Through Sound: Volume 1

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    This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government
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