Reducción de ruido granular en imágenes de eco cardiografía por composición temporal y filtrado digital /

El presente proyecto consiste en la reducción de ruido granular en imágenes de eco cardiografía con la ayuda de dos técnicas de post‐procesamiento de señales, composición temporal y filtro digital de difusión anisotrópica. El diseño e implementación de la metodología, tanto del procesamiento de las muestras como de los métodos de evaluaciones está basado en los estudios mostrados en la bibliografía adjunta, con algunas modificaciones para la adaptación a las condiciones reales del experimento. El procesamiento se realiza sobre muestras reales que han sido aportadas por médicos. Se implementaron dos métodos: composición temporal y filtro digital de difusión anisotrópica. Se evaluó la relación señal‐ruido y el índice de calidad universal de las imágenes antes y después del procesamiento para corroborar el mejoramiento de las mismas. Se empleó el software Matlab para implementar los algoritmos y se desarrolló una interfaz que le permite al usuario cargar las muestras que desea procesar, realizar el procesamiento de las mismas y visualizar los resultados cualitativa y cuantitativamente. Los resultados muestran mejoras en las imágenes a nivel de reducción de ruido granular en las imágenes resultantes, definición de las estructuras, preservación de los bordes y en general, mejora en la calidad de las imágenesIncluye bibliografía, anexos e índic

PENGOLAHAN FILTERING DAN CONTRAST ENHANCEMENT UNTUK MENINGKATKAN KUALITAS RESOLUSI CITRA ULTRASONOGRAFI ABDOMEN

Evaluasi penyaringan dan peningkatan kontras telah dilakukan untuk meningkatkan visualisasi gambar USG perut. Penelitian ini bertujuan untuk mengevaluasi hasil gabungan metode median filter dan filter Wiener menggunakan metode Histogram Equalization (HE), Contras Limited Adaptive Histogram Equalization (CLAHE), Contras Stretching (CS) secara kuantitatif menggunakan Mean Squared Error (MSE) dan Peak Signal-to-Noise Ratio (PSNR) dan kualitatif berdasarkan hasil wawancara dengan ahli radiologi. Data yang digunakan dalam penelitian ini adalah 30 data sekunder dari pasien USG abdomen. Penelitian dilakukan dengan mengkonversi data citra dan menerapkan 6 kombinasi metode menjadi 30 data. Hasil yang diperoleh pada studi kuantitatif kombinasi median filter dengan CS menunjukkan hasil pengolahan yang mudah diinterpretasikan berdasarkan nilai rata-rata MSE dan PSNR dengan nilai 51,537 dan 31,355 dB, dan secara kualitatif ahli radiologi menunjukkan kombinasi median dan CS memiliki hasil yang mudah

EVALUASI TEKNIK FILTERING DENGAN CONTRAST ENHANCEMENT UNTUK MENINGKATKAN VISUALISASI CITRA ULTRASOUND ABDOMEN

Telah dilakukan evaluasi filtering dan contrast enhancement untuk meningkatkan visualisasi citra ultrasound perut. Penelitian ini bertujuan untuk mengevalusi hasil kombinasi dari metode filter median dan filter Wiener dengan metode Histogram Equalization (HE), Contrast Limited Adaptive Histogram Equalization (CLAHE), Contrast Stretching (CS)secara kuantitatif menggunakan nilai Mean Squared Error (MSE) dan Peak Signal-to-Noise Ratio (PSNR). Secara kualiatatif berdasarkan hasil wawancara dengan dokter radiologi. Data yang digunakan pada penelitian sebanyak 30 data sekunder pasien ultrasound abdomen. Penelitian dilakukan dengan mengkonversi data citra dan menerapkan 6 metode kombinasi terhadap 30 data. Hasil yang diperoleh pada penelitian secara kuantitatif dan kualitatif memberikan hasil yang sama yaitu kombinasi filter median dengan CS merupakan hasil kombinasi dengan keluaran yang mudah untuk menginterpretasikan citra

Filtering Enhanced Traffic Management System (ETMS) Altitude Data

Enhanced Traffic Management System (ETMS) stores all the information gathered by the Federal Aviation Administration (FAA) from aircraft flying in the US airspace. The data stored from each flight includes the 4D trajectory (latitude, longitude, altitude and timestamp), radar data and flight plan information. Unfortunately, there is a data quality problem in the vertical channel and the altitude component of the trajectories contains some isolated samples in which a wrong value was stored. Overall, the data is generally accurate and it was found that only 0.3% of the altitude values were incorrect, however the impact of these erroneous data in some analyses could be important, motivating the development of a filtering procedure. The approach developed for filtering ETMS altitude data includes some specific algorithms for problems found in this particular dataset, and a novel filter to correct isolated bad samples (named Despeckle filter). As a result, all altitude errors were eliminated in 99.7% of the flights affected by noise, while preserving the original values of the samples without bad data. The algorithm presented in this paper attains better results than standard filters such as the median filter, and it could be applied to any signal affected by noise in the form of spikes

Performance analysis of speckle ultrasound image filtering

Over the last three decades, several despeckling filters have been developed by researchers to reduce the speckle noise inherently present in ultrasound B-scan images without losing the diagnostic information. This paper compiles and compares well-known techniques mostly used in the smoothing or suppression of speckle noise in ultrasound images. A comparison of the methods studied is done based on an experiment, using quality metrics, texture analysis and interpretation of profiles to evaluate their performance and show the benefits each one can contribute to denoising and feature preservation. To test the methods, a noise-free image of a kidney is used and then the Field II program simulates a B-mode ultrasound image. By this way, the smoothing techniques can be compared using numeric metrics, taking the noise-free image as a reference. In this study, a total of 17 different speckle reduction algorithms have been documented based on spatial filtering, diffusion filtering and wavelet filtering, with 15 qualitative metrics estimation. We use the tendencies observed in our study in real images. A new evaluation metric is proposed to evaluate the despeckling results.info:eu-repo/semantics/publishedVersio

An Effective Ultrasound Video Communication System Using Despeckle Filtering and HEVC

The recent emergence of the high-efficiency video coding (HEVC) standard promises to deliver significant bitrate savings over current and prior video compression standards, while also supporting higher resolutions that can meet the clinical acquisition spatiotemporal settings. The effective application of HEVC to medical ultrasound necessitates a careful evaluation of strict clinical criteria that guarantee that clinical quality will not be sacrificed in the compression process. Furthermore, the potential use of despeckle filtering prior to compression provides for the possibility of significant additional bitrate savings that have not been previously considered. This paper provides a thorough comparison of the use of MPEG-2, H.263, MPEG-4, H.264/AVC, and HEVC for compressing atherosclerotic plaque ultrasound videos. For the comparisons, we use both subjective and objective criteria based on plaque structure and motion. For comparable clinical video quality, experimental evaluation on ten videos demonstrates that HEVC reduces bitrate requirements by as much as 33.2% compared to H.264/AVC and up to 71% compared to MPEG-2. The use of despeckle filtering prior to compression is also investigated as a method that can reduce bitrate requirements through the removal of higher frequency components without sacrificing clinical quality. Based on the use of three despeckle filtering methods with both H.264/AVC and HEVC, we find that prior filtering can yield additional significant bitrate savings. The best performing despeckle filter (DsFlsmv) achieves bitrate savings of 43.6% and 39.2% compared to standard nonfiltered HEVC and H.264/AVC encoding, respectively