scholarly journals Perceiving Perpendicular and Parallel Contours in the Frontoparallel Plane

2018 ◽  
Author(s):  
Ekaterina Koshmanova ◽  
Tadamasa Sawada
Keyword(s):  
Frontoparallel Plane

What Hinders Accurate Depiction of Projective Shape?

Perception ◽  
1995 ◽  
Vol 24 (9) ◽  
pp. 995-1010 ◽  
Author(s):  
Emiel Reith ◽  
Chang Hong Liu
Keyword(s):  
Da Vinci ◽  
The Other ◽  
Frontoparallel Plane ◽  
Glass Pane ◽  
Drawing Task ◽  
Visual Projection ◽  
Vertical Glass ◽  
Perceptual Abilities ◽  
Improved Accuracy ◽  
Projective Shape

Adult subjects drew the visual projection of two models. One model was a trapezoid placed in the frontoparallel plane. The other was a tilted rectangle which displayed the same projective shape on a frontoparallel plane as the trapezoid. The drawing conditions were varied in two ways: the model remained available for inspection during the drawing task or it was masked after initial inspection; the subjects drew on paper placed flat on the table or on a vertical glass pane placed in front of the model (ie on a da Vinci window). The results were that (i) the projective shape of the frontoparallel trapezoid was reproduced accurately whereas that of the tilted rectangle was systematically distorted in the direction of its actual physical dimensions; (ii) when subjects drew on paper, the presence or absence of a view of the model made no difference to the amount of distortion; (iii) drawing on a da Vinci window improved accuracy even when the model was hidden. These findings provide information about the relative roles of object-centred knowledge, perceptual abilities, and depiction skills in drawing performance.

Errors in Estimating the Orientation of Dot Patterns

Perception ◽  
1989 ◽  
Vol 18 (2) ◽  
pp. 237-242 ◽  
Author(s):  
P Lánský ◽  
Naum Yakimoff ◽  
T Radil ◽  
L Mitrani
Keyword(s):  
Pattern Analysis ◽  
Frontoparallel Plane ◽  
The Subject ◽  
Left And Right ◽  
The Mean ◽  
The Difference

The error in estimating the orientation of a dot pattern was measured as the difference between the orientation of the least-squared-distances line (LS-line) of the pattern and the orientation of a line adjusted by the subject to match the perceived orientation of the pattern. Analysis of the mean errors (averaged over ten subjects) obtained for one hundred patterns confirmed that the orientation of the LS-line represents the orientation of elongated dot-patterns. It is shown that estimated orientation was systematically biased towards the nearest 45° oblique meridian. This bias points to the importance of the ±45° directions as natural norms for left- and right-side tilt in the frontoparallel plane.

scholarly journals Apparent distortion of the frontoparallel plane from wide-field motion parallax

2010 ◽  
Vol 1 (3) ◽  
pp. 324-324
Author(s):  
V. Cornilleau-Peres ◽  
L.C. Tai ◽  
L. -F. Cheong
Keyword(s):  
Motion Parallax ◽  
Wide Field ◽  
Frontoparallel Plane

Multimeridional Apparent Frontoparallel Plane: Relation between Stimulus Orientation Angle and Compensating Tilt Angle

1992 ◽  
Vol 69 (7) ◽  
pp. 544-549 ◽  
Author(s):  
ARNULF REMOLE ◽  
STEPHEN M. CODE ◽  
CYNTHIA E. MATYAS ◽  
MURRAY A. McLEOD ◽  
CONNIE K. TO
Keyword(s):  
Tilt Angle ◽  
Orientation Angle ◽  
Stimulus Orientation ◽  
Frontoparallel Plane

Visual Directions of Two Stimuli in Panum's Limiting Case

Perception ◽  
1994 ◽  
Vol 23 (9) ◽  
pp. 1037-1048 ◽  
Author(s):  
Sachio Nakamizo ◽  
Koichi Shimono ◽  
Michiaki Kondo ◽  
Hiroshi Ono
Keyword(s):  
Sagittal Plane ◽  
Visual Direction ◽  
Frontoparallel Plane ◽  
Retinal Disparity ◽  
Limiting Case

Visual directions of the two stimuli in Panum's limiting case with different interstimulus and convergence distances confirmed the predictions from the reformulated Wells—Hering's laws of visual direction. In experiment 1, six observers each converged on the midpoint of the interstimulus axis at 30, 60, and 90 cm from the eyes and adjusted a probe on the fixation plane to be in the same visual direction as that of each stimulus. Visual direction of the far stimulus was always nonveridical whereas that of the near stimulus was veridical only when its retinal disparity was small. In experiment 2, three observers each converged on the intersection of mid-sagittal plane and (a) the frontoparallel plane of the near stimulus, (b) that of the midpoint between the two stimuli, or (c) that of the far stimulus. The midpoint of the interstimulus axis was 60 cm from the eyes. Visual direction of the far stimulus was veridical only with convergence at the far plane. Visual direction of the near stimulus was veridical with convergence at the near plane, and also, only when its retinal disparity was small, with convergence at the two other planes.

Occlusion Constraints and Stereoscopic Slant

Perception ◽  
1997 ◽  
Vol 26 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Jukka Häkkinen ◽  
Göte Nyman
Keyword(s):  
Binocular Vision ◽  
Retinal Image ◽  
Three Dimensional ◽  
Vertical Axis ◽  
The Other ◽  
Necessary Condition ◽  
Slant Perception ◽  
Frontoparallel Plane ◽  
Reduction Effect

In binocular vision horizontal magnification of one retinal image leads to a percept of three-dimensional slant around a vertical axis. It is demonstrated that the perception of slant is diminished when an occlusion interpretation is possible. A frontoparallel plane located in the immediate vicinity of a slanted surface in a location which allows a perception of occlusion reduces the magnitude of perceived slant significantly. When the same plane is placed on the other side, the slant perception is normal because there is no alternative occlusion interpretation. The results indicate that a common border between the occluder and a slanted surface is not a necessary condition for the reduction effect. If the edges are displaced and the edge of the slanted surface is placed in a location in which it could be occluded, the effect still appears.

Perception of Depth in Rotating Objects: 2. Perspective as a Determinant of Stereokinesis

1967 ◽  
Vol 25 (2) ◽  
pp. 621-628 ◽  
Author(s):  
Roy B. Mefferd ◽  
Betty A. Wieland
Keyword(s):  
Viewing Time ◽  
Frontoparallel Plane ◽  
Rotating Objects

10 Os viewed under extreme reduction conditions 5 simple, plane, featureless figures and an Ames trapezoidal window as they rotated slowly (5 rpm) in the frontoparallel plane. Judgments of shape, slant, and type of movement were obtained for 4-min. periods first with binocular regard and later with monocular. As more perspective cues were introduced and as viewing time increased, there were progressive increases in depth indicants with all three types of judgments.

The Visual Discrimination of Bending

Perception ◽  
10.1068/p5641 ◽  
2007 ◽  
Vol 36 (7) ◽  
pp. 980-989 ◽  
Author(s):  
J Farley Norman ◽  
Elizabeth Y Wiesemann ◽  
Hideko F Norman ◽  
M Jett Taylor ◽  
Warren D Craft
Keyword(s):  
Visual Discrimination ◽  
Weber Fraction ◽  
Retinal Images ◽  
Frontoparallel Plane ◽  
Oriented Plane

The sensitivity of observers to nonrigid bending was evaluated in two experiments. In both experiments, observers were required to discriminate on any given trial which of two bending rods was more elastic. In experiment 1, both rods bent within the same oriented plane, and bent either in a frontoparallel plane or bent in depth. In experiment 2, the two rods within any given trial bent in different, randomly chosen orientations in depth. The results of both experiments revealed that human observers are sensitive to, and can reliably detect, relatively small differences in bending (the average Weber fraction across experiments 1 and 2 was 9.0%). The performance of the human observers was compared to that of models that based their elasticity judgments upon either static projected curvature or mean and maximal projected speed. Despite the fact that all of the observers reported compelling 3-D perceptions of bending in depth, their judgments were both qualitatively and quantitatively consistent with the performance of the models. This similarity suggests that relatively straightforward information about the elasticity of simple bending objects is available in projected retinal images.

Learning to See Stereokinetic Effects

Perception ◽  
1987 ◽  
Vol 16 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Paola Bressan ◽  
Giorgio Vallortigara
Keyword(s):  
Rigid Body ◽  
Structure From Motion ◽  
Incubation Time ◽  
Stimulus Pattern ◽  
Circular Ring ◽  
Frontoparallel Plane ◽  
Stereokinetic Effect ◽  
Flat Pattern

The Saturn illusion is a stereokinetic effect that occurs when a flat pattern composed of a full ellipse with two symmetrical semirings is rotated slowly in the frontoparallel plane. Subjects report seeing an egg-shaped object inserted into a circular ring, and the two objects move solidly into 3-D space as a single rigid body. Inexperienced observers show a conspicuous delay before reaching this percept. Two experiments are reported in which it is shown that this incubation time progressively decreases with repeated exposures to the stimulus pattern. A certain amount of time (14 s on average) is, however, required to obtain the effect, even after six successive exposures. It is argued that this time, which is independent of the speed of rotation and is not further reducible, is a fixed entity and is needed to compute the most rigid 3-D solution from deformations in the 2-D image. The results are discussed in relation to current theories of perception of structure from motion.

Sign in / Sign up

Export Citation Format

Share Document