Toni Järvenpää

Measuring color breakup of stationary images in field‐sequential‐color displays

— Color breakup is an artifact perceivable on field-sequential-color (FSC) displays, both in stationary and in moving images. In this work, a unique device and a method for measuring color breakup on stationary images is proposed. Rotating the field of view of a high-speed measurement camera in milliseconds simulates saccadic behavior. The target can be a virtual display, a direct-view display or a projector image. Captured images can be used for quantifying the color breakup of a target display. The results along with an exploration of their application to breakup characterization will be presented.

Optical characterization of autostereoscopic 3-D displays

— Display-measurement methods different from conventional 2-D display measurements are needed for verifying the optical characteristics of autostereoscopic (3-D) displays and for comparing different 3-D display technologies. Industry is lacking standardized measurement methods, and the reported results can not always be compared. The selected set of characteristics discussed in this paper and partly defining the quality of the 3-D experience are crosstalk, viewing freedom, and optimum viewing distance. Also, more conventional display characteristics such as luminance are discussed, since the definitions for these characteristics in 3-D mode usually differ from those used for the 2D displays. We have investigated how these chosen 3-D display characteristics can be objectively measured from transmissive two-view and multiview 3-D displays. The scope of this article is to generally define those basic characteristics as well as the different measurement methods. Most of the 3-D characteristics can be derived from the luminance and colors versus the viewing angle. Either a conoscopic or a goniometric measurement system can be used, as long as the angular and stray-light properties are suitable and known. The characteristics and methods are currently discussed in the display-quality standardization forums.

An augmented reality interface to contextual information

In this paper, we report on a prototype augmented reality (AR) platform for accessing abstract information in real-world pervasive computing environments. Using this platform, objects, people, and the environment serve as contextual channels to more information. The user’s interest with respect to the environment is inferred from eye movement patterns, speech, and other implicit feedback signals, and these data are used for information filtering. The results of proactive context-sensitive information retrieval are augmented onto the view of a handheld or head-mounted display or uttered as synthetic speech. The augmented information becomes part of the user’s context, and if the user shows interest in the AR content, the system detects this and provides progressively more information. In this paper, we describe the first use of the platform to develop a pilot application, Virtual Laboratory Guide, and early evaluation results of this application.

7.2: Measuring Color Breakup of Stationary Images in Field‐Sequential‐Color Displays

Color breakup is an artifact perceivable on field-sequential color (FSC) displays, both in stationary and in moving images. In this work a unique device for measuring color breakup on stationary images is presented. Target FSC display can be a virtual display, a direct-view display or a projector. Turning the view of a high-speed measurement camera in milliseconds simulates saccadic eye movement. Captured images can be used e.g. in studies of color breakup theories.

Contextual information access with Augmented Reality

We have developed a prototype platform for contextual information access in mobile settings. Objects, people, and the environment are considered as contextual channels or cues to more information. The system infers, based on gaze, speech and other implicit feedback signals, which of the contextual cues are relevant, retrieves more information relevant to the cues, and presents the information with Augmented Reality (AR) techniques on a handheld or head-mounted display. The augmented information becomes potential contextual cues as well, and its relevance is assessed to provide more information. In essence, the platform turns the real world into an information browser which focuses proactively on the information inferred to be the most relevant for the user. We present the first pilot application, a Virtual Laboratory Guide, and its early evaluation results.

Compact near-to-eye display with integrated gaze tracker

Near-to-Eye Display (NED) offers a big screen experience to the user anywhere, anytime. It provides a way to perceive a larger image than the physical device itself is. Commercially available NEDs tend to be quite bulky and uncomfortable to wear. However, by using very thin plastic light guides with diffractive structures on the surfaces, many of the known deficiencies can be notably reduced. These Exit Pupil Expander (EPE) light guides enable a thin, light, user friendly and high performing see-through NED, which we have demonstrated. To be able to interact with the displayed UI efficiently, we have also integrated a video-based gaze tracker into the NED. The narrow light beam of an infrared light source is divided and expanded inside the same EPEs to produce wide collimated beams out from the EPE towards the eyes. Miniature video camera images the cornea and eye gaze direction is accurately calculated by locating the pupil and the glints of the infrared beams. After a simple and robust per-user calibration, the data from the highly integrated gaze tracker reflects the user focus point in the displayed image which can be used as an input device for the NED system. Realizable applications go from eye typing to playing games, and far beyond.

Exploring the interaction design space for interactive glasses

In this paper, we explore the interaction design space for interactive glasses. We discuss general issues with interactive glasses (i.e., optics, technology, social, form factors), and then concentrate on the topic of the nature of interaction with glasses and its implications to provide a delightful user experience with the NotifEye.

Reading e-books on a near-to-eye display: Comparison between a small-sized multimedia display and a hard copy

Eighty-seven participants read an e-book either from a near-to-eye display, a small-size display or a hard copy. Eyestrain, visually induced motion sickness, changes in visual functioning, user experience, and the essential optical parameters of the reading equipment were evaluated. The results indicate that reading from a hard copy was the most comfortable experience. All near-to-eye displays induced eyestrain and sickness symptoms, but the magnitude of these symptoms varied according to the device. The adverse symptoms were related to problems with the display optics and design, text layout, headset fit, use context, and individual differences.

Optical characterization and ergonomical factors of near‐to‐eye displays

Abstract— Near-to-eye displays (NEDs) have unique optical properties requiring different characterization techniques compared to direct-view display measurements. Here, a new version of a NED measurement system is introduced, and optical measurements of five commercially available consumer NED products are discussed. Luminance, focal distance, qualified viewing space, angular properties, and interocular differences are among the values. In addition, these results are compared to extensive subjective studies. The main intention is not to benchmark between the different products, but to show that display measurements are important for NEDs. According to the results, the determination of NEDs characteristics helps to predict the subjective experiences, but the nature of the relation between subjective and objective findings is rather complex and depends on several NED-, user-, and task-related features. Measured characteristics indicate that with a conventional biocular NED system approach of using two microdisplays and their enlarging optics, it is a design and a manufacturing challenge to build an ergonomically satisfactory NED device that fits everyone.

Optical characterization and measurements of autostereoscopic 3D displays

3D or autostereoscopic display technologies offer attractive solutions for enriching the multimedia experience. However, both characterization and comparison of 3D displays have been challenging when the definitions for the consistent measurement methods have been lacking and displays with similar specifications may appear quite different. Earlier we have investigated how the optical properties of autostereoscopic (3D) displays can be objectively measured and what are the main characteristics defining the perceived image quality. In this paper the discussion is extended to cover the viewing freedom (VF) and the definition for the optimum viewing distance (OVD) is elaborated. VF is the volume inside which the eyes have to be to see an acceptable 3D image. Characteristics limiting the VF space are proposed to be 3D crosstalk, luminance difference and color difference. Since the 3D crosstalk can be presumed to be dominating the quality of the end user experience and in our approach is forming the basis for the calculations of the other optical parameters, the reliability of the 3D crosstalk measurements is investigated. Furthermore the effect on the derived VF definition is evaluated. We have performed comparison 3D crosstalk measurements with different measurement device apertures and the effect of different measurement geometry on the results on actual 3D displays is reported.