Fourier tabanlı optik modülasyon ile tek çekimde alt-pozlama görüntülerinin çıkarılması

Through pixel-wise optical coding of images during exposure time, it is possible to extract sub-exposure images from a single capture. Such a capability can be used for different purposes, including high-speed imaging, high-dynamic-range imaging and compressed sensing. Here, we demonstrate a sub-exposure image extraction method, where the exposure coding pattern is inspired from frequency division multiplexing idea of communication systems. The coding masks modulate subexposure images in such a way that they are placed in non-overlapping regions in Fourier domain. The sub-exposure image extraction process involves digital filtering of the captured signal with proper band-pass filters. The prototype imaging system incorporates a Liquid Crystal over Silicon (LCoS) based spatial light modulator synchronized with a camera for pixel-wise exposure coding.Pozlama süresinde piksellerin optik olarak kodlanması vasıtasıyla, tek bir görüntü kaydından birden çok alt-pozlama görüntüsünün elde edilmesi mümkündür. Böyle bir kabiliyet; yüksek hızlı görüntüleme, yüksek dinamik aralıklı görüntüleme ve sıkıştırılmış görüntüleme gibi çeşitli amaçlar için kullanılabilir. Bu tezde, kodlama örüntüsünün haberleşme sistemlerinde kullanılan "frekans bölüşümlü çoğullama" fikrinden esinlenildiği bir alt-pozlama görüntüsü elde etme metodu sunulmaktadır. Bu metodda; optik maskeler, alt-pozlama görüntülerini Fourier uzayında örtüşmeyecek şekilde yerleştirilmesini sağlayacak şekilde tasarlanmıştır. Alt-pozlama görüntüleri, kaydedilmiş sinyalin uygun şekilde bant-geçiren filtrelerden geçirilmesiyle elde edilmektedir. Prototip görüntüleme sistemi; piksel bazlı kodlama için Liquid Crystal over Silicon (LCoS) teknolojisine dayalı bir uzamsal ışık modülatörü ile senkronize edilmiş bir kamera vasıtasıya gerçekleştirilmiştir

Computational Imaging Methods for Improving Resolution in Biological Microscopy

Optical microscopy is an essential tool for biological research, as it allows for non-invasive imaging of small animals. However, optical microscopy has its limits. Due to the low light level, fluorescence microscopy prohibits high speed imaging, making it difficult to study fast dynamic biological processes. In addition, optical blur due to the diffraction of light results in limited spatial resolution, particularly when using objective lenses with low numerical apertures. In this thesis, we propose computational imaging methods to overcome these limitations using a combination of novel image acquisition procedures and reconstruction algorithms.The first part of this thesis deals with improving temporal resolution in fluorescence microscopy to image rapid, repeating processes. We take advantage of multiple acquisitions, each taken with different time delays or temporally modulated illumination patterns, to recover high frequency information that is lost with traditional imaging. We demonstrate our method to image the beating heart in live embryonic zebrafish with reduced motion blur and high resolution in time.The second part of this thesis deals with reducing spatial blur in optical projection tomography, a form of optical microscopy that uses multiple 2D projections to reconstruct a 3D image of an object. We propose a method to reduce the optical distortion (as characterized by the system's optical point spread function) that can be implemented with a scanning acquisition approach combined with a modified filtered backprojection algorithm for reconstruction. We demonstrate our method to image blood vessels in larval zebrafish with high spatial resolution and reduced out-of-focus blur.The final part of this thesis deals with the dimensional limitation of 2D sensors for measuring 3D motion in microscopy. We propose a method to combine two-dimensional motion estimates from multiple views to recover out-of-plane velocity and reconstruct a divergence-free, three-dimensional velocity field. We demonstrate our method to measure, for the first time, dynamic blood flow in 3D inside the beating heart of a live zebrafish using optical microscopy.This thesis provides new tools that integrate custom image acquisition procedures and image reconstruction algorithms to overcome the resolution limitations -- temporal, spatial, and out-of-plane velocity resolution -- in optical microscopy. The methods presented in this thesis, in particular the single camera, active illumination method for temporal superresolution in fluorescence microscopy, will be directly applicable to a broad range of biological studies and will open up new perspectives for imaging small organisms in 3D (and time) with high spatio-temporal resolution

Coded exposure photography: motion deblurring using fluttered shutter

In a conventional single-exposure photograph, moving objects or moving cameras cause motion blur. The exposure time defines a temporal box filter that smears the moving object across the image by convolution. This box filter destroys important high-frequency spatial details so that deblurring via deconvolution becomes an illposed problem. Rather than leaving the shutter open for the entire exposure duration, we ”flutter ” the camera’s shutter open and closed during the chosen exposure time with a binary pseudo-random sequence. The flutter changes the box filter to a broad-band filter that preserves high-frequency spatial details in the blurred image and the corresponding deconvolution becomes a well-posed problem. We demonstrate that manually-specified point spread functions are sufficient for several challenging cases of motionblur removal including extremely large motions, textured backgrounds and partial occluders. ACM Transactions o Graphics (TOG

Research on Restoration Algorithm of Partially Motion-Blurred Images of Vehicle Based on Video Sequence

图像复原是图像处理技术中一个极具应用价值的重要研究领域，也是学术界和工业界一直以来的研究热点之一。运动模糊图像的复原作为图像复原的一种，主要研究如何从一幅因运动而造成模糊的图像中提取有用信息，复原出清晰的原始图像，具有重要的现实意义。 与全局运动模糊图像的复原相比，局部运动模糊图像的复原不仅需要估计图像退化过程的点扩散函数PSF（pointspreadfunction），利用PSF反卷积去模糊，而且需要检测和提取模糊区域，甚至在某些条件下还需要判别模糊区域的模糊类型。为了有效地复原局部运动模糊的车辆图像，本文从以下几个方面展开了基于多帧的车辆图像复原算法研究： 首先，为了准确、快速地检测和...Image restoration is a very important research field with highly application value in the area of image processing technology, also in academia and industry has been one of the research hotspots. As a kind of image restoration, motion-blurred image restoration which mainly discusses how to extract useful information from motion-blurred image and to restore the original clear image, has very import...学位：工程硕士院系专业：信息科学与技术学院计算机科学系_计算机技术学号：2302009115270

Single-shot ultrafast optical imaging

Single-shot ultrafast optical imaging can capture two-dimensional transient scenes in the optical spectral range at ≥100 million frames per second. This rapidly evolving field surpasses conventional pump-probe methods by possessing real-time imaging capability, which is indispensable for recording nonrepeatable and difficult-to-reproduce events and for understanding physical, chemical, and biological mechanisms. In this mini-review, we survey state-of-the-art single-shot ultrafast optical imaging comprehensively. Based on the illumination requirement, we categorized the field into active-detection and passive-detection domains. Depending on the specific image acquisition and reconstruction strategies, these two categories are further divided into a total of six subcategories. Under each subcategory, we describe operating principles, present representative cutting-edge techniques, with a particular emphasis on their methodology and applications, and discuss their advantages and challenges. Finally, we envision prospects for technical advancement in this field

Single-shot ultrafast optical imaging

Single-shot ultrafast optical imaging can capture two-dimensional transient scenes in the optical spectral range at ≥100 million frames per second. This rapidly evolving field surpasses conventional pump-probe methods by possessing real-time imaging capability, which is indispensable for recording nonrepeatable and difficult-to-reproduce events and for understanding physical, chemical, and biological mechanisms. In this mini-review, we survey state-of-the-art single-shot ultrafast optical imaging comprehensively. Based on the illumination requirement, we categorized the field into active-detection and passive-detection domains. Depending on the specific image acquisition and reconstruction strategies, these two categories are further divided into a total of six subcategories. Under each subcategory, we describe operating principles, present representative cutting-edge techniques, with a particular emphasis on their methodology and applications, and discuss their advantages and challenges. Finally, we envision prospects for technical advancement in this field