Perception of Eye Scans with the Müller-Lyer Stimuli: Evidence for Filter Theory

1982 ◽  
Vol 54 (3) ◽  
pp. 683-692 ◽  
Author(s):  
J. Timothy Petersik
Keyword(s):  
Horizontal Line ◽  
Modulation Transfer ◽  
Physical Stimulus ◽  
Line Segments ◽  
Filter Theory ◽  
Lyer Illusion ◽  
Wide Range ◽  
Scan Path ◽  
Low Pass ◽  
Perceptual Distortions

Ginsburg's filter theory successfully accounts for the perceptual distortions perceived in a wide range of illusions and bistable phenomena. Essentially, the theory proposes that illusory distortions are the natural consequence of low-pass spatial filtering (based upon the human modulation transfer function) of the physical stimulus. With regard to the Müller-Lyer illusion, predictions based upon filter theory and human scan-path data are in accord. However, data linking filter theory's predictions regarding perceptual experiences associated with the illusion to the eye-scan results have been missing. In the present experiment subjects provided subjective estimations of their own eye scans while viewing each of the following stimuli: the fins-out member of the Müller-Lyer illusion, the fins-in member of the Müller-Lyer illusion, and a finless horizontal line (variations of each stimulus consisted of one, two, and three line segments). The analysis of these data supported three predictions that were derived from filter theory. Potential problems facing filter theory are also addressed.

Pitch related to spectral edges of broadband signals

1992 ◽  
Vol 336 (1278) ◽  
pp. 375-382 ◽  
Keyword(s):  
Fundamental Frequency ◽  
Basilar Membrane ◽  
Comparison Tone ◽  
Harmonic Signals ◽  
Wide Range ◽  
Spectral Components ◽  
Neuronal Processes ◽  
Low Pass ◽  
Harmonic Components ◽  
Hearing System

A complex tone often evokes a pitch sensation associated with its extreme spectral components, besides the holistic pitch associated with its fundamental frequency. We studied the edge pitch created at the upper spectral edge of complexes with a low-pass spectrum by asking subjects to adjust the frequency of a sinusoidal comparison tone to the perceived pitch. Measurements were performed for different values of the fundamental frequency and of the upper frequency of the complex as well as for three different phase relations of the harmonic components. For a wide range of these parameters the subjects could adjust the comparison tone with a high accuracy, measured as the standard deviation of repeated adjustments, to a frequency close to the nominal edge frequency. The detailed dependence of the matching accuracy on temporal parameters of the harmonic complexes suggests that the perception of the edge pitch in harmonic signals is related to the temporal resolution of the hearing system. This resolution depends primarily on the time constants of basilar-membrane filters and on additional limitations due to neuronal processes.

scholarly journals HIGH RESOLUTION CAMERA DESIGN PLANNING THEORETICAL FOUNDATIONS FOR DRIVING SYSTEMS

2021 ◽  
Author(s):  
Viacheslav S. Stadnichuk ◽  
Valentin G. Kolobrodov ◽  
Oleksii O. Mosolab ◽  
Denis Yu. Kondratenko ◽  
Dmytro I. Ryabokon
Keyword(s):  
High Resolution ◽  
Optical Glass ◽  
Light Sensitivity ◽  
Design Parameters ◽  
Optical Parameters ◽  
Functional Requirements ◽  
Modulation Transfer ◽  
Road Signs ◽  
Wide Range ◽  
Camera Design

Background. Analysis of statistical data showed that in most cases the cause of the accident is driver error and, as a consequence, violation of traffic rules. In this regard, over the past 10 years, active developments in the field of recognition of road signs and other obstacles in the path of a car have been actively developing. Car manufacturers offer ready-made built-in systems, mounted behind the interior rearview mirror and connected to the car’s on-board computer, which carries out further control of the car in a critical situation. The main disadvantage of these systems of this class is the low range of recognition of road signs, the dependence of optical parameters on temperature and low light sensitivity. Objective. The purpose of the paper is to model an athermal objective for a high-resolution camera, investigate the characteristics of lenses depending on the ambient temperature. Methods. Analysis and modeling of objectives, lenses, optical glass from different materials. Results. A high-resolution camera objective for all types of cars is proposed. An athermal objective was developed for a high-resolution camera. Conclusions. The optimized athermal design of the visible spectrum objective for long-range car cameras is considered. Car cameras typically have a fixed focus, and forward-facing cameras typically require relatively long focal lengths to provide information about distant objects. The optical system for these cameras should provide high resolution, as well as operate in a wide range of ambient temperatures. The camera design parameters are derived from the functional requirements of road sign recognition at a distance of 200 m. The objective design has five lenses with spherical surfaces. The objective has a relative aperture of f/2 and a modulation transfer function (MTF) of more than 0.5 at 111 l/mm over the entire temperature range.

An Illusory Contour Can Facilitate Visually Induced Self-Motion Perception

2018 ◽  
Vol 31 (8) ◽  
pp. 715-727
Author(s):  
Shinji Nakamura ◽  
Shin’ya Takahashi
Keyword(s):  
Motion Perception ◽  
Illusory Contour ◽  
Uniform Motion ◽  
Horizontal Line ◽  
Illusory Contours ◽  
End Points ◽  
Line Segments ◽  
Illusory Perception ◽  
Vertically Aligned ◽  
Self Motion

Abstract Uniform motion of a visual stimulus induces an illusory perception of the observer’s self-body moving in the opposite direction (vection). The present study investigated whether vertical illusory contours can affect horizontal translational vection using abutting-line stimulus. The stimulus consisted of a number of horizontal line segments that moved horizontally at a constant speed. A group of vertically aligned segments created a ‘striped column’, while line segments in adjoining columns were shifted vertically to make a slight gap between them. In the illusory contour condition, the end points of the segments within the column were horizontally aligned to generate vertical illusory contours. In the condition with no illusory contour, these end points were not aligned within the column so that the illusory contour was not perceived. In the current study, 11 participants performed this experiment, and it was shown that stronger vection was induced in the illusory contour condition than in the condition with no illusory contour. The results of the current experiment provide novel evidence suggesting that non-luminance-defined visual features have a facilitative effect on visual self-motion perception.

A New Capacitance Multiplier Structure with High Multiplication Factor for Ultra-Low-Frequency Filter in Biomedical Applications

2019 ◽  
Vol 29 (07) ◽  
pp. 2050109
Author(s):  
Yan Li ◽  
Yong Liang Li
Keyword(s):  
Biomedical Applications ◽  
Low Frequency ◽  
Multiplication Factor ◽  
Frequency Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Physiological Signal ◽  
Wide Range ◽  
Low Pass ◽  
Capacitance Multiplier

A novel capacitance multiplier is proposed to implement an ultra-low-frequency filter for physiological signal processing in biomedical applications. With the proposed multiplier, a simple first-order low-pass filter achieves a [Formula: see text]3-dB frequency of 33.4[Formula: see text]μHz with a 1-pF capacitance and a 20[Formula: see text]k[Formula: see text] resistance. This corresponds to a multiplication factor of as large as [Formula: see text]. By changing the controlling terminal, the [Formula: see text]3-dB frequency can be tuned in a wide range of 33.4[Formula: see text]μHz–6.3[Formula: see text]kHz.

Optical “Seeing” over Level Terrain

1967 ◽  
Vol 1 (1) ◽  
pp. 34-35
Author(s):  
C. E. Coulman
Keyword(s):  
Transfer Function ◽  
Basic Research ◽  
Horizontal Line ◽  
Optical Transfer Function ◽  
Modulation Transfer ◽  
Unit Distance ◽  
Optical Images ◽  
Image Movement ◽  
Optical Transfer ◽  
Solar Astronomy

This work is aimed at understanding the phenomena which affect the sharpness and stability of optical images transmitted through the atmosphere. A brief description is given of the results obtained to date from an experimental field-study directed at establishing a connection between optics and meteorology. Most of the work has, so far, been conducted in daytime because our main application is to solar astronomy; other fields such as surveying, aerial reconnaissance and so on can also benefit from basic research in atmospheric optics.A horizontal line of sight over uniform, level terrain presents the simplest case for study. The optical transfer function (OTF) of the system comprising an air-path and telescope objective has been measured with an image analyser which is a modified form of stellar seeing-monitor. The outputs of this analyser are proportional to the modulus and argument of the OTF. The modulus, or modulation transfer function (MTF), is a measure of image contrast; the fluctuations of the argument measure image movement, or “dancing”. The OTF is a function of spatial frequency f (cycles per unit distance) which may be altered by radial movement of the scanning graticule of the image-analvser.

The Mueller-Lyer Illusion Produced by Features in Maps

1996 ◽  
Vol 40 (23) ◽  
pp. 1242-1246
Author(s):  
William Schmidt ◽  
Douglas J. Gillan
Keyword(s):  
Present Experiment ◽  
Road Segment ◽  
Place Names ◽  
Line Segments ◽  
The Road ◽  
Lyer Illusion ◽  
Road Segments

Maps consist of lines converging onto line segments. These converging lines resemble elements of the Mueller-Lyer illusion (MLEs) which cause map readers to overestimate the length of a road segment (if the lines go outward from the end of the segment) or underestimate the length (if the lines go inward from the end of the segment) (Gillan, Schmidt, & Hanowski, 1996). The present experiment investigates whether a similar effect occurs when place names converge on a road segment. Subjects estimated road segments framed by outward-going MLEs made up of place names to be significantly longer than road segments framed by inward-going MLEs. The type of characters in the place names (English characters vs. symbols) and requiring subjects to locate the road segment by the names in the MLE had no effect on the degree of misestimation induced. The implications of these findings for a variety of displays are discussed.

CONVOLUTION FILTERING OF GRAVITY AND MAGNETIC MAPS

Geophysics ◽  
1965 ◽  
Vol 30 (2) ◽  
pp. 281-283 ◽  
Author(s):  
P. Edward Byerly
Keyword(s):  
Downward Continuation ◽  
Filter Theory ◽  
Wavenumber Domain ◽  
Gravity And Magnetic ◽  
Single Ring ◽  
Low Pass ◽  
Convolution Filter

This note discusses some applications of convolution filter theory to gravity and magnetic maps. Sampling of the field is equivalent to a multiplication, and the corresponding convolution determines the sampling spectrum. If aliasing is acceptably small a specific filtering multiplication in the wavenumber domain corresponds to a convolution of a set of grid coefficients with gridded map values. The application of this theory to single‐ring residuals, certain vertical derivatives, downward continuation, and low‐pass filtering is discussed.

Turbulence Estimation Using Fast-Response Thermistors Attached to a Free-Fall Vertical Microstructure Profiler

2016 ◽  
Vol 33 (10) ◽  
pp. 2065-2078 ◽  
Author(s):  
Yasutaka Goto ◽  
Ichiro Yasuda ◽  
Maki Nagasawa
Keyword(s):  
Temperature Gradient ◽  
Frequency Response ◽  
Turbulence Intensity ◽  
Free Fall ◽  
Fast Response ◽  
Double Pole ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Wide Range ◽  
Low Pass

AbstractEstimation of turbulence intensity with a fast-response thermistor is examined by comparing the energy dissipation rate from a Fastip Probe, model 07 (FP07), thermistor with from a shear probe, both of which are attached to a free-fall microstructure profiler with the fall rate of 0.6–0.7 m s−1. Temperature gradient spectra corrected with previously introduced frequency response functions represented by a single-pole low-pass filter yields with a bias that strongly depends on turbulence intensity. Meanwhile, the correction with the form of a double-pole low-pass filter derives less bias than of single-pole low-pass filter. The rate is compatible with when the double-pole correction with the time constant of 3 × 10−3 s is applied, and 68% of data are within a factor of 2.8 of in the wide range of = 10−10–3 × 10−7 W kg−1. The rate is still compatible with even in the anisotropy range, where the buoyancy Reynolds number is 20–100. Turbulence estimation from the fast-response thermistor is thus confirmed to be valid in this range by applying the appropriate correction to temperature gradient spectra. Measurements with fast-response thermistors, which have not been common because of their poor frequency response, are less sensitive to the vibration of profilers than those with shear probes. Hence, measurements could be available when a fast-response thermistor is attached to a CTD frame or a float, which extends the possibility of obtaining much more turbulence data in deep and wide oceans.

scholarly journals Improving Efficiency in Power Production and Transmission for Offshore Solar Farms using Bifacial Panel Design and HVDC

2021 ◽  
Vol 16 ◽  
pp. 164-177
Author(s):  
Bell David Du Hong ◽  
Ha Thu Le
Keyword(s):  
Green Energy ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Hvdc System ◽  
Wide Range ◽  
Low Pass ◽  
System Output ◽  
Global Concern ◽  
Offshore Power Generation ◽  
Low Pass Filters

As higher demand for power becomes a global concern and offshore power generation becomes more popular, more options should be explored. This study investigates the use of bifacial photovoltaic (PV) panels for offshore solar farms. In addition, it explores the use of HVDC for transmitting the solar power to onshore grid. The results show that bifacial panels have much higher efficiency compared to monofacial panels where the efficiency improvement ranges from 8.5% to 24.8% for a wide range of irradiance (100-1000 W/m2). The newer Voltage Source Converter (VSC) HVDC has high potential for future deployment thanks to its advantages. However, the harmonics from a considered VSC-HVDC system is severe. Some fitters have been designed to mitigate the harmonics. LC low-pass filters are proved to be most effective where they reduce the Total Harmonics Distortion (THD) of the system output voltage from 68.84% to 2.93%. The results are supportive for developing offshore solar farms that provide green energy while preserving land for other purposes.

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