Screen Edge Research Articles

Circling motion and screen edges as an alternative input method for on-screen target manipulation

Purpose: To investigate a new alternative interaction method, called circling interface, for manipulating on-screen objects. To specify a target, the user makes a circling motion around the target. To specify a desired pointing command with the circling interface, each edge of the screen is used. The user selects a command before circling the target. Method: To evaluate the circling interface, we conducted an experiment with 16 participants, comparing the performance on pointing tasks with different combinations of selection method (circling interface, physical mouse and dwelling interface) and input device (normal computer mouse, head pointer and joystick mouse emulator). Results: A circling interface is compatible with many types of pointing devices, not requiring physical activation of mouse buttons, and is more efficient than dwell-clicking. Across all common pointing operations, the circling interface had a tendency to produce faster performance with a head-mounted mouse emulator than with a joystick mouse. The performance accuracy of the circling interface outperformed the dwelling interface. Conclusions: It was demonstrated that the circling interface has the potential as another alternative pointing method for selecting and manipulating objects in a graphical user interface.Implications for RehabilitationA circling interface will improve clinical practice by providing an alternative pointing method that does not require physically activating mouse buttons and is more efficient than dwell-clicking.The Circling interface can also work with AAC devices.

Sound Lets You See: A Phenomenology of Hearing Screen Media

This phenomenological investigation of ocularcentrism in screen media proceeds deductively. First, the significance of screen media is demonstrated. Next, synaesthetic merging of human senses is shown to begin with the body and to produce ready substitutions of seeing and hearing. The final deduction explores apperception – “seeing with” – a foundation of the phenomenological method. Sounds emanating from beyond the screen edge stimulate an expanded experience – a window to a wider world. This marginal consciousness has surprising power to dictate the audiovisual impact. In summary, off-screen sounds, combined with visual closure of objects partially hidden by the frame edge, stimulate in screen sense the apperception of a co-extensive world beyond the picture frame. Sound lets you see.

Sagittal plane alignment evaluation during walking in adult spinal deformity: gait analysis using DARTFISH

Material and method We researched consequent 40 adult spinal deformity patients in our institute during January 2012 to January 2013. The mean age of patients was 60.1 years old. The research item was SVA, LL, TK, PT, PI, SS and EGA. We have movie recording from the side of the patients walking. We set markers at the External auditory pore and the Greater trochanter, and de fine the straight line between them as the EG line. We then measure the angle between the horizontal and EG lines. We call the angle “EGA-DARTFISH” if measured (over time) during gait analysis, and “EGA-XP” if measured radiographically. [Fig. 1, 2] We used the StatFlex ver.6.0 the statistical processing. We were calibrated in order to perform more accurate measurement. In this measurement, distortion at the screen edges is negligible.

Integrodifferential Equations of the Vector Problem of Electromagnetic Wave Diffraction by a System of Nonintersecting Screens and Inhomogeneous Bodies

The vector problem of electromagnetic wave diffraction by a system of bodies and infinitely thin screens is considered in a quasi-classical formulation. The solution is sought in the classical sense but is defined not in the entire spaceR3but rather everywhere except for the screen edges. The original boundary value problem for Maxwell’s equations system is reduced to a system of integrodifferential equations in the regions occupied by the bodies and on the screen surfaces. The integrodifferential operator is treated as a pseudodifferential operator in Sobolev spaces and is shown to be zero-index Fredholm operator.

Spatial profile and singularities of the edge-diffracted beam with a multicharged optical vortex

We analyze the edge diffraction of circular Laguerre–Gaussian beams LG02 and LG03 carrying multicharged optical vortices (OVs), with special attention to spatial properties and evolution of the diffracted beam. The problem is considered numerically within the frame of paraxial approximation and the Fresnel diffraction theory. The diffracted beam evolution is interpreted on the basis of the incident beam symmetry breakdown and decomposition of a higher-order OV into a set of single-charged secondary OVs. Upon propagation, the separate OVs describe specific trajectories within the diffracted beam cross section but in the far field they are localized on the symmetry axis parallel to the screen edge. The OVs' positions in each cross section reflect information of the screen edge position with respect to the incident beam axis. If the incident OV is stopped by the screen, the diffracted beam possesses no OV just behind the screen but in the course of its further propagation, single-order OVs appear consecutively so that in the far field the number of OVs equals to the absolute topological charge of the incident OV. Possible applications for the remote measurements of small linear displacements are discussed.

Scalar problem of plane wave diffraction by a system of nonintersecting screens and inhomogeneous bodies

The scalar problem of plane wave diffraction by a system of bodies and infinitely thin screens is considered in a quasi-classical formulation. The solution is sought in the classical sense but is defined not in the entire space ℝ3 but rather everywhere except for the screen edges. The original boundary value problem for the Helmholtz equation is reduced to a system of weakly singular integral equations in the regions occupied by the bodies and on the screen surfaces. The equivalence of the integral and differential formulations is proven, and the solvability of the system in the Sobolev spaces is established. The integral equations are approximately solved by the Bubnov-Galerkin method. The convergence of the method is proved, its software implementation is described, and numerical results are presented.

Movement time to edge and non-edge targets

Time to capture a target at the edge of a screen is expected to be less than when the target is slightly away from the screen edge. This is due to the effective target width, in the direction of cursor movement, being large when the target is at the screen edge, allowing a user to control the movement only in a direction perpendicular to the direction of movement. An experiment with 71 participants and a range of Fitts’ Index of Difficulty (ID) showed a strong difference in the capture times of targets at the screen edge and targets placed one pixel from the screen edge. This advantage is typically 100 ms, independent of the ID of the movement.Practitioner Summary: Movement time to icons placed at the screen edge (no space between icon and screen edge) is faster than when they are placed a short distance from the edge (as in Microsoft Windows).

Diffraction in time: An exactly solvable model

In the recent years, mater-wave interferometry has attracted growing attention due to its unique suitability for high-precision measurements and study of fundamental aspects of quantum theory. Diffraction and interference of matter waves can be observed not only at a spatial aperture (such as a screen edge, slit, or grating), but also at a time-domain aperture (such as an absorbing barrier, or "shutter", that is being periodically switched on and off). The wave phenomenon of the latter type is commonly referred to as "diffraction in time". Here, we introduce a versatile, exactly solvable model of diffraction in time. It describes time-evolution of an arbitrary initial quantum state in the presence of a time-dependent absorbing barrier, governed by an arbitrary aperture function. Our results enable a quantitative description of diffraction and interference patterns in a large variety of setups, and may be used to devise new diffraction and interference experiments with atoms and molecules.

Examining the costs of multiple trajectory pointing techniques

Pointing techniques that offer users multiple trajectories to a target have the potential to reduce pointing time by allowing a shorter than normal movement distance. However, such techniques potentially introduce additional elements into the pointing task involving identification of the alternative trajectories, assessment of their relative performance, and selection of the one to use. These additional tasks may reduce or negate the benefits of offering shorter paths. To better understand these issues, we developed a methodology for controlling the relative benefits of alternative target trajectories, and used it to evaluate three interfaces—a ‘pointer wrapping’ technique that allows the cursor to traverse from one screen edge to the opposing edge, and a system allowing users to choose between multiple cursors in two configurations (‘Ninja cursors’). We found that performance with these techniques was significantly worse than that predicted by Fitts' law for a single cursor, suggesting that the additional elements in their use are significant. Detailed analysis of behaviour during acquisitions showed that much of this cost is accrued in the mental preparation that precedes motor action, and in additional volatility in the pointing movements. We discuss how the method and findings may assist those developing enhanced pointing techniques.

Automated optical inspection system for digital TV sets

This article proposes a real-time test and verification system for full-reference automatic image quality assessment and verification of digital TV sets. Digital camera is used for acquisition of the TV screen content in order to ensure quality assessment of the content as perceived by the user. Test has been executed in three steps: image acquisition by camera, TV screen content extraction and full-reference image quality assessment. The TV screen content is extracted from the captured image in two steps: detection of the TV screen edge and transformation of the TV screen content to dimensions of the reference image. Three image comparison methods are incorporated to perform full-reference image quality assessment. Reference image for quality assessment is obtained either by grabbing the image from TV set or by capturing the TV screen content on the golden sample. Digital camera was later replaced with DSP-based camera for image acquisition and algorithm execution which brought significant performance improvements. The comparison methods were tested under constant and variable illumination conditions. The proposed system is used to automate the verification step on the final production line of digital TV sets. The time required for verification step decreased by a factor of 5 when using the proposed system on the final production line instead of a manual one.

The Potential Method for the Reactance Wave Diffraction Problem in a Scale of Spaces

Abstract This paper is concerned with a screen type boundary value problem arising from the wave diffraction problem with a reactance condition. We consider the problem in a weak formulation within Bessel potential spaces, and where both cases of a complex and a pure real wave number are analyzed. Using the potential method, the boundary value problem is converted into a system of integral equations. The invertibility of the corresponding matrix pseudodifferential operator is shown in appropriate function spaces which allows the conclusion about the existence and uniqueness of a weak solution to the original problem. Higher regularity properties of solutions are also proved to exist in some scale of Bessel potential spaces, upon the corresponding smoothness improvement of given data. In particular, the 𝐶 α -smoothness of solutions in a neighbourhood of the screen edge is established with arbitrary α < 1 in the two-dimensional case and α < 1/2 in the three-dimensional case.

Creation of plasma density transitions short compared to the plasma skin depth

A plasma based electron beam source apparatus is described which creates a plasma with two distinct density regions separated by a transition which is shorter than the plasma skin depth kp−1 of either region. This sharp density modulation is achieved by using a perforated stainless steel screen to filter half of a diffusing plasma column. A simple physical model predicts that the length of the plasma density transition will vary with the distance from the screen. For a weakly magnetized plasma, the transition length will be twice the distance, on a line normal to the screen plane, from the screen edge to the location where the transition is measured. The plasma column is generated using an argon discharge plasma source. It has a peak density of approximately 3.5×1013cm−3 and a full width half maximum width of 5 cm. The discharge source utilizes a 7.5 cm diameter LaB6 disk cathode heated to 1300 °C using a graphite heater. The plasma column is filtered with a 78μm thick stainless steel sheet with 152μm holes and 21% open area. Plasma density transitions with lengths between 0.74 and 0.95kp−1 were measured.

Wide-angle diffraction of the laser beam by a sharp edge

Using a rigorous theory of diffraction, we explain the origin and analyze the structure of a wide-angle illuminated area observed when a limited beam is diffracted by the sharp edge of an opaque screen. It is shown that the formed plume has the structure of a cylindrical wave traveling from the screen edge and its amplitude is proportional to the beam amplitude at this edge. The observed structure is Young’s boundary wave produced by diffraction of the limited beam.

Traffic noise prediction with the parabolic equation method: validation of a split-step Padé approach in complex environments.

This study deals with sound propagation in typical traffic noise conditions. The numerical results are obtained through the split-step Padé method and the discrete random Fourier modes technique. These are first evaluated qualitatively, by color contour maps showing noise propagation, diffraction by an impedance discontinuity or a screen edge, and scattering by atmospheric turbulence. Next, our numerical results are quantitatively validated by comparison with analytical models and other parabolic equation models. For all the atmospheric conditions and geometrical configurations available in literature, the agreement between the different methods is very good, except for some cases involving the atmospheric turbulence. However, in those particular cases, the split-step Padé results are shown to be more consistent with physical theory. Finally, our method seems to be very powerful and reliable for traffic noise prediction.

Path-linking interpretation of Kirchhoff diffraction

The Kirchhoff-diffraction integral is often used to describe the (scalar) wave field from a monochromatic point source in the presence of ‘opaque’ screens. Despite criticisms that can be made of its ‘derivation’, the Kirchhoff field is an exact solution of the wave equation, and exactly obeys definite, though unusual, boundary conditions (Kottler 1923, 1965). Here, the path-integral picture of wave fields is used to interpret the Kirchhoff-diffraction field in terms of all conceivable propagation paths, whether or not they pass through the opaque screens. Specifically, it is noted that the Kirchhoff field equals Ʃ(1 ─ m )ψ m , where the sum is over all integers m , and ψ m is the wave field due to all paths from the source to the field point for which the number of outward screen crossings minus the number of backwards screen crossings is m . Expressed more topologically, m is the total linking number of a path, when closed by any unobstructed path, with the screen edge lines. Other models of diffraction by screens are compared with Kirchhoff diffraction in the path interpretation.

Fresnel peculiarity of the response function of a quantum adiabatic system

We demonstrate in this paper that the response function of any quantum adiabatic system as a function of the frequency has a peculiarity in the vicinity of the frequency of the external field applied to the system. This peculiarity is similar to the one which appears in the photon distribution in the case of Fresnel diffraction of light at a screen edge.

New interference phenomenon in quasimolecular radiation spectrum

Interference effects appearing in the radiation spectrum of quasimolecules created in atomic collisions are discussed in the framework of the stationary phase approximation. A new interference phenomenon, which is very similar to the Fresnel diffraction of light at a screen edge, is proposed.

On the diffraction of autowaves

The paper is concerned with the passage of autowaves through one or two holes in an impermeable screen, their diffraction at a screen edge, and their passage through narrow channels in a thick screen. The following interesting phenomena were observed: aperiodicity in wave trains behind the screen (chaos) and frequency demultiplication in the case of a periodic train of autowaves incident on a narrow hole in an impermeable screen; the effect of autowave reflection from a hole; the possibility for a narrow channel to become a source of periodic autowaves. The studies were performed by numerical experiments with a model of an excitable medium of the FitzHugh-Nagumo type.

Diffraction by a nonplanar screen

This paper is concerned with diffraction of short waves by a nonplanar screen (two-dimensional case, Dirichlet boundary condition). The high-frequency asymptotic approximation to the solution is obtained. First the wave field of the primary wave is found in a neighbourhood of the screen edge and then this field is continued along the boundary. Secondary waves arise here as the consequence of interaction between the edge and the primary wave. The secondary wave is diffracted by another edge of the screen, and a third order wave arises, and so on. This process gives the formulas for the wave field in a neighbourhood of the screen. Green's formula is used to continue the solution outside of this neighbourhood.

Pyramid Tracing vs. Ray Tracing for the simulation of sound propagation in large rooms.

The aim of this paper is to introduce a new computational model (RAMSETE) for the simulation of sound propagation in large rooms; the model can easily be adapted to work outdoor, and can consider diffraction effects around screen edges and sound paths passing through (light) panels. However, this paper focuses on room acoustics, and particularly on rooms with non-Sabinian behaviour. In fact, the Pyramid Tracing algorithm does not involve an hybrid computation scheme, with a reverberant tail superposed to the deterministic early reflections estimate, as it is common with other diverging beam tracers (cone tracers, gaussian beam tracers, etc.). This make it possible to study also sound fields characterised by double-slope sound decays, inside spaces with not comparable dimensions and inhomogeneous sound absorption. It is well known that the same capabilities were already present in the (original) Ray Tracing scheme, but requiring much longer computation time. In fact, a correct Ray Tracing implementation can be considered as the reference standard for any (faster) numerical code based on the Geometrical Acoustics assumptions. After a brief introduction to some important details of the two algorithms, the results obtained in three cases are presented. The first is a typical Sabinian room (a reverberating chamber), the second is the coupling of two rooms with different average absorption (a theatre with its stage), the third is a typical industrial building (having an height very little compared to other dimensions) with nonuniform sound absorption (baffles under the ceiling). The results show how the Pyramid Tracing can give results very similar to the original Ray Tracing, provided that a proper adjustment of the parameters is performed. On the other hand, the magnitude of the errors that can be done with improper parameter settings is delimited and discussed.