Registration is a fundamental task in image processing used to match two or more pictures taken, for example, at different times, from different sensors, or from different viewpoints. Virtually all large systems which evaluate images require the registration of images, or a closely related operation, as an intermediate step. Specific examples of systems where image registration is a significant component include matching a target with a real-time image of a scene for target recognition, monitoring global land usage using satellite images, matching stereo images to recover shape for autonomous navigation, and aligning images from different medical modalities for diagnosis.Over the years, a broad range of techniques has been developed for various types of data and problems. These techniques have been independently studied for several different applications, resulting in a large body of research. This paper organizes this material by establishing the relationship between the variations in the images and the type of registration techniques which can most appropriately be applied. Three major types of variations are distinguished. The first type are the variations due to the differences in acquisition which cause the images to be misaligned. To register images, a spatial transformation is found which will remove these variations. The class of transformations which must be searched to find the optimal transformation is determined by knowledge about the variations of this type. The transformation class in turn influences the general technique that should be taken. The second type of variations are those which are also due to differences in acquisition, but cannot be modeled easily such as lighting and atmospheric conditions. This type usually effects intensity values, but they may also be spatial, such as perspective distortions. The third type of variations are differences in the images that are of interest such as object movements, growths, or other scene changes. Variations of the second and third type are not directly removed by registration, but they make registration more difficult since an exact match is no longer possible. In particular, it is critical that variations of the third type are not removed. Knowledge about the characteristics of each type of variation effect the choice of feature space, similarity measure, search space, and search strategy which will make up the final technique. All registration techniques can be viewed as different combinations of these choices. This framework is useful for understanding the merits and relationships between the wide variety of existing techniques and for assisting in the selection of the most suitable technique for a specific problem.

A survey of image registration techniques

Let's read! We will often find out this sentence everywhere. When still being a kid, mom used to order us to always read, so did the teacher. Some books are fully read in a week and we need the obligation to support reading. What about now? Do you still love reading? Is reading only for you who have obligation? Absolutely not! We here offer you a new book enPDFd the perception of the visual world to read.

The Perception of the Visual World. By James J. Gibson. U.S.A.: Houghton Mifflin Company, 1950 (George Allen & Unwin, Ltd., London). Price 35s.

There are declines with age in speed of processing, working memory, inhibitory function, and long-term memory, as well as decreases in brain structure size and white matter integrity. In the face of these decreases, functional imaging studies have demonstrated, somewhat surprisingly, reliable increases in prefrontal activation. To account for these joint phenomena, we propose the scaffolding theory of aging and cognition (STAC). STAC provides an integrative view of the aging mind, suggesting that pervasive increased frontal activation with age is a marker of an adaptive brain that engages in compensatory scaffolding in response to the challenges posed by declining neural structures and function. Scaffolding is a normal process present across the lifespan that involves use and development of complementary, alternative neural circuits to achieve a particular cognitive goal. Scaffolding is protective of cognitive function in the aging brain, and available evidence suggests that the ability to use this mechanism is strengthened by cognitive engagement, exercise, and low levels of default network engagement.

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The Adaptive Brain: Aging and Neurocognitive Scaffolding

A classic photographic task is the mapping of the potentially high dynamic range of real world luminances to the low dynamic range of the photographic print. This tone reproduction problem is also faced by computer graphics practitioners who map digital images to a low dynamic range print or screen. The work presented in this paper leverages the time-tested techniques of photographic practice to develop a new tone reproduction operator. In particular, we use and extend the techniques developed by Ansel Adams to deal with digital images. The resulting algorithm is simple and produces good results for a wide variety of images.

/pdf/photographic-tone-reproduction-for-digital-images-k89wmpv97f.pdf

Photographic tone reproduction for digital images

Blood vessels usually have poor local contrast, and the application of existing edge detection algorithms yield results which are not satisfactory. An operator for feature extraction based on the optical and spatial properties of objects to be recognized is introduced. The gray-level profile of the cross section of a blood vessel is approximated by a Gaussian-shaped curve. The concept of matched filter detection of signals is used to detect piecewise linear segments of blood vessels in these images. Twelve different templates that are used to search for vessel segments along all possible directions are constructed. Various issues related to the implementation of these matched filters are discussed. The results are compared to those obtained with other methods. >

/pdf/detection-of-blood-vessels-in-retinal-images-using-two-2lxvrugvz5.pdf

Detection of blood vessels in retinal images using two-dimensional matched filters

Visually induced motion sickness (VIMS) is evoked by conflicting motion sensory signals within the brain. Use of the simulator sickness questionnaire (SSQ) or postural stability measures to quantify one’s VIMS experience only measures the changes between preand post-experiment. The motion sickness susceptibility questionnaire (MSSQ) is widely used to measure individual’s sensitivity to motion sickness, but its applicability to VIMS has not been proven. We are introducing a novel VIMS susceptibility measure by combining measures of the subject’s “sensitivity” and “endurance” to VIMS. The proposed VIMS susceptibility measure was tested for various VIMS inducing conditions, and demonstrated its effectiveness by conducting both between-subjects and within-subject comparisons for different VIMS conditions. c © 2017 Society for Imaging Science and Technology. [DOI: 10.2352/J.ImagingSci.Technol.2017.61.6.060405] INTRODUCTION When viewing the contents of stereoscopic 3D (S3D) displays, observers often complain of various symptoms of discomfort, such as light-headedness, dizziness, queasiness, and nausea. Such symptoms are similar to those of motion sickness experienced in cars or boats. When they are mainly induced by visual motions, these symptoms are referred to as visually induced motion sickness (VIMS).

Quantifying Visually Induced Motion Sickness (VIMS) During Stereoscopic 3D Viewing Using Temporal VIMS Rating.

The visual system can distinguish different levels of blur and different levels of excess sharpness. Adaptation alters this capacity so that the adapted blur (or sharp) level looks more like a normal, properly focused image. Here, we describe the more general pattern of aftereffects of blur and sharp adaptation by measuring matching functions, using video clips from a DVD movie as stimuli. Results show that blur and sharp adaptation are selective: The sharpening aftereffects of blur adaptation are strongest for blurry videos while the blurring aftereffects of sharp adaptation are strongest for sharp videos. Despite the spatiotemporal variability of our adaptor and test stimuli, we found adaptation effects similar in magnitude to previous studies using invariant static images. A recent model of blur adaptation can be simplified to explain the form of our data, leading us to conclude that what we see as blur/sharp adaptation is a consequence of narrowband contrast adaptation.

Adaptation to blurred and sharpened video.

Computerized driving simulators are good platforms for evaluating driving abilities but the wealth of data collected must be analyzed with careful attention to the underlying questions of the research program. In the context of an ongoing study we have developed analyses to quantify vehicle-handling skills and head movement behaviors that are relevant to hemianopia (loss of half the visual field on the same side in both eyes). By evaluating skills in specific segments of the drive (straights, curves, turns) we can address important driving behaviors that are relevant to the condition under investigation. These behaviors may be masked when studied across the entire drive, but may be easily detected in specific drive segments. In this methodology paper we describe the development of our assessments and analyses for patients with hemianopia, and use sample data plots from individual cases to demonstrate that our analyses are sensitive to lane position biases, vehicle handling difficulties, and inadequate or compensatory head movements at intersections.

/pdf/analysis-of-driving-behavior-where-it-matters-41yq9857hi.pdf

Analysis of Driving Behavior Where it Matters

Purpose In most states, people with reduced visual acuity may legally drive with the aid of a bioptic telescope. However, concerns have been raised that the ring scotoma may impair detection of peripheral hazards. Using a driving simulator, we tested the hypothesis that the fellow eye would be able to compensate for the ring scotoma when using a monocular telescope. Methods Sixteen bioptic users completed three drives with binocular viewing interleaved between three drives with monocular viewing. Forty pedestrians appeared and ran on the road for 1 second, including 26 within the ring scotoma, while participants were reading road signs through their own monocular telescopes. Head movements were analyzed to determine whether the pedestrian appeared before or only while using the telescope. Results For pedestrians that appeared only during bioptic use and were likely in the area of the ring scotoma, detection rates were significantly higher in binocular (fellow eye can compensate) than monocular (fellow eye patched) viewing (69% vs. 32%; P < 0.001); this was true for both current and noncurrent drivers. For pedestrians appearing before or after bioptic use, detection rates did not differ in binocular and monocular viewing. However, detection rates were even higher and reaction times shorter when the telescope was not being used. Conclusions Both current and noncurrent drivers'  fellow eyes were able to compensate, at least in part, for the ring scotoma. Translational Relevance When using monocular telescopes, the fellow eye reduces the impact of the ring scotoma on hazard detection in binocular viewing.

Hazard Detection With Monocular Bioptic Telescopes in a Driving Simulator

Both binocular and monocular HMDs designed to be used non-immersively were found to create minimal interruption of the visual fields making them safe to wear (but probably not to use) in mobile situations. A small opaque display can be positioned to provide a see through functionality.

http://www.researchgate.net/profile/Russell_Woods2/publication/250998643_33.4_The_Impact_of_Non-Immersive_HMDs_on_the_Visual_Field/links/0912f510011375c10a000000.pdf

Eli Peli

Papers

Quantifying Visually Induced Motion Sickness (VIMS) During Stereoscopic 3D Viewing Using Temporal VIMS Rating.

Adaptation to blurred and sharpened video.

Analysis of Driving Behavior Where it Matters

Hazard Detection With Monocular Bioptic Telescopes in a Driving Simulator

33.4: The Impact of Non-Immersive HMDs on the Visual Field