Computational Cameras: Approaches, Benefits and Limits

A computational camera uses a combination of optics and software to produce images that cannot be taken with traditional cameras. In the last decade, computational imaging has emerged as a vibrant field of research. A wide variety of computational cameras have been demonstrated - some designed to achieve new imaging functionalities and others to reduce the complexity of traditional imaging. In this article, we describe how computational cameras have evolved and present a taxonomy for the technical approaches they use. We explore the benefits and limits of computational imaging, and describe how it is related to the adjacent and overlapping fields of digital imaging, computational photography and computational image sensors

Reinterpretable Imager: Towards Variable Post-Capture Space, Angle and Time Resolution in Photography

We describe a novel multiplexing approach to achieve tradeoffs in space, angle and time resolution in photography. We explore the problem of mapping useful subsets of time-varying 4D lightfields in a single snapshot. Our design is based on using a dynamic mask in the aperture and a static mask close to the sensor. The key idea is to exploit scene-specific redundancy along spatial, angular and temporal dimensions and to provide a programmable or variable resolution tradeoff among these dimensions. This allows a user to reinterpret the single captured photo as either a high spatial resolution image, a refocusable image stack or a video for different parts of the scene in post-processing. A lightfield camera or a video camera forces a-priori choice in space-angle-time resolution. We demonstrate a single prototype which provides flexible post-capture abilities not possible using either a single-shot lightfield camera or a multi-frame video camera. We show several novel results including digital refocusing on objects moving in depth and capturing multiple facial expressions in a single photo

Image Processing Technique by Multi Scale Retinex Algorithm to Flame Characteristics Investigation

خوارزميات معالجة الصورة كانت ذات تأثير فائق في احتساب ومعرفة خصائص اللهب مثل الارتفاع، الطول والسمك والتي في اغلب الأحيان لا يمكن قياسها في الظروف التشغيلية وذلك من خلال اخذ صورة رقمية للهب او الشعلة بواسطة كامرة فائقة السرعة لثلاث أنواع من الوقود المستخدم في توليد الشعلة  باستخدام نفاث وقود معد لسريان الوقود ومن ثم انتاج الشعلة والذي يعتمد على عدة متغيرات مثل معدل تدفق الوقود, قطر النفاث ومقدار الضغط المسلط. في هذا البحث تم تطبيق طريقتين رياضية لتمثيل البيانات لغرض قياس خصائص ومواصفات اللهب المتكون من نوع الانتشار. الأول كان تطبيق توزيع ) (Wien’s   للجسم الأسود مع ملف المعالجة الخاص ببرنامج الماثلاب , والثاني يعتمد على مناطق شدة اللهب. ان الهدف من هذه الاختيارات هو لتحسين الصورة من حيث التقطيع ومعالجة التشوه الحاصل من ذلك والحصول على دقة عالية. كذلك دراسة تأثير الأشعة تحت الحمراء على مخرجات الضوء المرئي والحصول على الصورة النهائية. اخيرا فان الصورة المندمجة والتي سوف تتشكل بواسطة المعدلات الوزنية   سوف تكتشف بواسطة الضوء المرئي والأشعة تحت الحمراء لتوهج اللهب. ان خواص الصورة الناتجة والتي سوف تدرس بواسطة الحفاظ على الألوان والدقة العالية للصورة الرقمية من خلال تحسين الصورة الأصلية وتقليل الضوضاء. النتائج بينت ان خوارزمية Retinex   أكثر ملائمة ومتقاربة في تحليل الصورة وتقليل التشوه الذي يحصل عليها وان الصورة المتولدة من اللهب ذات دقة ووضوح عال وان استجابة خوارزمية الرتنكس في التوزيع الوزني لتوهج الألوان الناتجة من شعلة الوقود الحيوي تبين انها ذات خصائص أعلى من الأنواع المستخدمة الأخرى. Image processing algorithms was more effected in modern processes to evaluate the flame characteristics such as height, length and thickness by taking digital image for flame by high speed camera for three different fuel types diesel, biodiesel and biofuel of jet flame by depend upon more variables effect such as mass flow rate, diameter of nozzle and compressed pressure. We will be applying two different mathematical methods in order to measuring some characteristics of diffusion flame. Where one depend upon Wiens distribution of a black body with MSR math-lab processing and another depend upon the intensity of the flame. These operations target to enhancing the exactitude of image segmentation and resolution. Secondly, feature extractions of the visible and infrared line images are performed, and the recognition of the target image is further completed. Finally, image fusion is performed by weighted averaging of the targets detected by visible light and infrared images The image properties are investigating by increase the knowledge of the color and resolution of digital image and enhancement the origin image by applying the concern algorithm and less the noise. The results show that the algorithm of retinex is suitable to analysis the digital image and not distortions on it

Segmentation of fetal 2D images with deep learning: a review

Image segmentation plays a vital role in providing sustainable medical care in this evolving biomedical image processing technology. Nowadays, it is considered one of the most important research directions in the computer vision field. Since the last decade, deep learning-based medical image processing has become a research hotspot due to its exceptional performance. In this paper, we present a review of different deep learning techniques used to segment fetal 2D images. First, we explain the basic ideas of each approach and then thoroughly investigate the methods used for the segmentation of fetal images. Secondly, the results and accuracy of different approaches are also discussed. The dataset details used for assessing the performance of the respective method are also documented. Based on the review studies, the challenges and future work are also pointed out at the end. As a result, it is shown that deep learning techniques are very effective in the segmentation of fetal 2D images.info:eu-repo/semantics/publishedVersio

Multiplexed photography : single-exposure capture of multiple camera settings

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 115-124).The space of camera settings is large and individual settings can vary dramatically from scene to scene. This thesis explores methods for capturing and manipulating multiple camera settings in a single exposure. Multiplexing multiple camera settings in a single exposure can allow post-exposure control and improve the quality of photographs taken in challenging lighting environments (e.g. low light or high motion). We first describe the design and implementation of a prototype optical system and associated algorithms to capture four images of a scene in a single exposure, each taken with a different aperture setting. Our system can be used with commercially available DSLR cameras and photographic lenses without modification to either. We demonstrate several applications of our multi-aperture camera, such as post-exposure depth of field control, synthetic refocusing, and depth-guided deconvolution. Next we describe multiplexed flash illumination to recover both flash and ambient light information as well as extract depth information in a single exposure. Traditional photographic flashes illuminate the scene with a spatially-constant light beam. By adding a mask and optics to a flash, we can project a spatially varying illumination onto the scene which allows us to spatially multiplex the flash and ambient illuminations onto the imager. We apply flash multiplexing to enable single exposure flash/no-flash image fusion, in particular, performing flash/no-flash relighting on dynamic scenes with moving objects. Finally, we propose spatio-temporal multiplexing, a novel image sensor feature that enables simultaneous capture of flash and ambient illumination.(cont.) We describe two possible applications of spatio-temporal multiplexing: single-image flash/no-flash relighting and white balancing scenes containing two distinct illuminants (e.g. flash and fluorescent lighting).by Paul Elijah Green.Ph.D

Multidimensional image enhancement from a set of unregistered differently exposed images

If multiple images of a scene are available instead of a single image, we can use the additional information conveyed by the set of images to generate a higher quality image. This can be done along multiple dimensions. Super-resolution algorithms use a set of shifted and rotated low resolution images to create a high resolution image. High dynamic range imaging techniques combine images with different exposure times to generate an image with a higher dynamic range. In this paper, we present a novel method to combine both techniques and construct a high resolution, high dynamic range image from a set of shifted images with varying exposure times. We first estimate the camera response function, and convert each of the input images to an exposure invariant space. Next, we estimate the motion between the input images. Finally, we reconstruct a high resolution, high dynamic range image using an interpolation from the non-uniformly sampled pixels. Applications of such an approach can be found in various domains, such as surveillance cameras, consumer digital cameras, etc

Future perspectives of digital pathology

Technological advances have enabled innovative solutions to be achieved in pathology based on digital imaging, now superseding those of conventional microscopy. Digital pathology has been defined as ‘virtual microscopy’ and depends on computer-generated digital imaging of microscope slides (WSI — whole slide imaging) which are in turn created, reviewed, managed, shared, analysed and interpreted. Such WSI systems and digital consulting platforms are now used for teaching, scientific research, telepathology / teleconsultation and diagnostics. They also permit easy and interactive sharing of WSI that can be integrated into other medical information systems. The software for automated image analysis and computer aided diagnosis can thereby make highly accurate diagnoses and help standardise study findings. Despite the technique’s many advantages, its noted drawbacks include high equipment and software costs, image quality issues of standardisation and most importantly, that pathologists are reluctant to use it routinely for making diagnoses

Design Analysis of a Sapce Based Chromotomographic Hyperspectral Imaging Experiment

This research develops the design of several components and/or systems for an experimental space-based chromotomographic hyperspectral imager that is being built by the Air Force Institute of Technology. The design work includes three separate topics. The first topic was the development of a structure utilizing finite element analysis and eigenanalysis for the ground-based version of the chromotomographic experiment (CTEx). The ground-based experiment was performed as a risk mitigation measure for the space-based experiment. The second topic includes a design review of a contractor\u27s proposed off-axis Mersenne telescope for the space-based chromotomographic hyperspectral imager. The work included the creation of preliminary verification requirements from the contract and sub- sequent analysis of the telescope design based on those requirements. The third topic addressed was a trade study of on-orbit focus, alignment, and calibration schemes for the space-based version of CTEx. The selected imaging focusing method entails imaging Earth-based sodium lights at night while stepping through several focus settings. The optimal focus setting shows the clearest sodium spectral features. The critical alignment concerns were identified as the alignment of the prism and of the collimated light onto the prism. The space-based CTEx utilizes three separate calibration methods involving vicarious Earth-based targets, and on-board laser diodes and spectral filters. The results of the research varied by topic. For the first topic, a structural assembly was successfully fabricated that allowed the goals of the ground-based CTEx to be met, validating the design approach. The design review for the second topic was successful with the contractor\u27s telescope design currently undergoing fabrication with delivery in May 2010. For the third topic, applicable methods and procedures were developed for the space-based CTEx