Spatiotemporal Filtering and the Interpolation Effect in Apparent Motion

Perception ◽  
1980 ◽  
Vol 9 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Michael J Morgan
Keyword(s):  
Apparent Motion ◽  
Spatial Position ◽  
Moving Target ◽  
Periodic Modulation ◽  
Continuous Motion ◽  
Spatiotemporal Filtering ◽  
Alignment Technique ◽  
As If

A target moving in discrete spatial steps with an appropriate interstep interval (ISI) can appear visually as if it is in continuous motion. The momentary spatial position of such a target is interpolated by the observer between its real physical positions. The extent of this interpolation was measured by a vernier alignment technique, and was found to decrease as the ISI was lengthened. A discretely moving target may be described as a continuously moving target on which is superimposed a periodic modulation of spatial position. It is shown that the traditional ‘staircase’ stimulus for apparent motion can be generalized to include other kinds of periodic modulation. With the use of various analog-filtered and digitally filtered versions of staircase stimuli with different ISIs, it was shown that the phenomenal interpolation of a periodically modulated moving target was affected only when the frequencies of modulation were less than about 25 Hz. The spatial amplitude of the modulation also has some effect.

Pulfrich Effect and the Filling in of Apparent Motion

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Michael J Morgan
Keyword(s):  
Eye Movements ◽  
Apparent Motion ◽  
Visual Direction ◽  
Moving Target ◽  
Alignment Technique ◽  
Pulfrich Effect ◽  
Series Of Experiments ◽  
Tracking Eye Movements ◽  
As If

In the stroboscopic version of the Pulfrich effect a filter is able to induce depth shifts in a target as if the latter were moving continuously, rather than merely occupying a series of discrete positions. This was examined in a further series of experiments, in which a visual alignment technique was used to measure the perceived visual direction of an apparently moving target in intervals between its presentations. Results showed that the target has approximately the visual direction that it would have if it were moving continuously. This ‘filling in’ of apparent motion was shown to occur before the level of stereopsis. The possible influence of tracking eye movements is discussed.

Interocular Delay Produces Depth in Subjectively Moving Noise Patterns

1980 ◽  
Vol 32 (3) ◽  
pp. 387-395 ◽  
Author(s):  
M. J. Morgan ◽  
Roger Ward
Keyword(s):  
Apparent Motion ◽  
Visual Noise ◽  
Moving Target ◽  
Dynamic Visual Noise ◽  
Spatial Disparity ◽  
Depth Effect ◽  
Retinal Disparity ◽  
As If

Brief apparent motion sequences were introduced into a dynamic visual dot display by spatially shifting selected dots between successive frames. This causes the display to look as if it is drifting continuously in one direction. When such a display is observed with an interocular delay the drifting dots appear to be displaced in depth, even though there is no conventional retinal disparity in the display. We found that the magnitude of this depth shift increased with the duration of the apparent motion sequences. With sequences of five or more frames duration the depth effect was very similar to that which would have been predicted with a continuously moving target. With briefer sequences the size of the depth effect decreased rapidly. We suggest that apparent motion cascades form the basis of Tyler's dynamic visual noise stereophenomenon, and we question his “random spatial disparity” hypothesis.

scholarly journals Apparent Motion and the Pulfrich Effect

Perception ◽  
1975 ◽  
Vol 4 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Michael J Morgan ◽  
Peter Thompson
Keyword(s):  
Apparent Motion ◽  
Target Position ◽  
Moving Object ◽  
Continuous Motion ◽  
Depth Effect ◽  
Pairing Effect ◽  
Moving Stimuli ◽  
Pulfrich Effect

The Pulfrich pendulum effect, obtained by viewing a moving object with a filter over one eye, was examined with target stimuli in apparent, rather than continuous, motion. The filter-induced depth effect persisted until a certain degree of intermittency in the presentations of the target was reached, and then it broke down. The degree of intermittency that could be tolerated before the depth effect broke down increased with the density of the filter. It could be argued that the filter determined a shift in the pairing of successive inputs to the eyes, such that the target position in the unfiltered eye was fused with the preceding target position in the filtered eye. However, it appears that the shifted-pairing effect cannot account for the depth impression seen when the target intermittency is less than about 30 ms. Below this value of intermittency a filter can produce a depth effect even when the delay it introduces is small in comparison to the intermittency of the input. The depth effect seen with intermittencies less than 30 ms appears to be of the same magnitude as that obtained with stimuli in continuous motion. It is concluded that a filter can cause two different kinds of depth shift with apparently moving stimuli.

Illusory Color Spread from Apparent Motion

2017 ◽  
Author(s):  
Carol M. Cicerone ◽  
Donald D. Hoffman
Keyword(s):  
Apparent Motion ◽  
Natural Scenes ◽  
Test Region ◽  
Stereoscopic View ◽  
Random Placement ◽  
Multiple Frames ◽  
As If

Color from motion describes the perception of subjective color that spreads over physically achromatic regions that are seen in apparent motion. Multiple frames are shown in quick succession, each frame composed of a random placement of differently colored dots on an achromatic background. From frame to frame, the locations of all dots are fixed, whereas the color assignments of dots in the test region change. Subjective color can be measured by color matches to and cancellation by real lights, can be seen with chromaticity differences alone in test and surround dots, and is independent of contour formation. In stereoscopic view, the perception of depth, as well as color and form, can be recovered in tandem with seeing motion. This chapter suggests that in natural scenes, mechanisms triggered by motion may reconstruct the depth, color, and form of partially obscured objects so they can be seen as if in plain view.

Spatial Induction of Illusory Motion

Perception ◽  
1982 ◽  
Vol 11 (2) ◽  
pp. 187-199 ◽  
Author(s):  
Walter C Gogel ◽  
Bernard W Griffin
Keyword(s):  
Apparent Motion ◽  
Alternative Interpretation ◽  
Test Point ◽  
Illusory Motion ◽  
Frontoparallel Plane ◽  
Continuous Motion ◽  
Motion In Depth ◽  
Physical Motion ◽  
Induced Motion

Induced motion is not limited to continuous motions presented on a frontoparallel plane. Experiments were conducted to investigate several varieties of induced motion to which theories of induced motion must apply. The observer indicated the perceived path of motion of a vertically moving test point to which induced motion at right angles to the physical motion was added by the motion of two inducing points. In experiment 1 all motions (both apparently and physically) were in a frontoparallel plane. It was found that discrete displacement as well as continuous motion of the test and inducing points produced substantial amounts of induction. In experiment 2 the inducing points were continuously moved in stereoscopic distance rather than remaining in an apparent frontoparallel plane. A large amount of apparent motion in depth was found in the vertically moving test point and was interpreted as an induced motion in depth. In experiment 3 an alternative interpretation of the phenomenon of experiment 2, in terms of an apparent vergence for the two images of the test point, was investigated and found to be unlikely. In experiment 4, with all the points moving continuously in a frontoparallel plane, eye motions as well as induced motions were measured, with the observer fixating either the test point or an inducing point. Substantial amounts of induction were obtained under both conditions of fixation. The consequences of these findings for theories of induced motion are discussed.

The oculomotor salience of flicker, apparent motion and continuous motion in saccade trajectories

2016 ◽  
Vol 235 (1) ◽  
pp. 181-191 ◽  
Author(s):  
Wieske van Zoest ◽  
Benedetta Heimler ◽  
Francesco Pavani
Keyword(s):  
Apparent Motion ◽  
Continuous Motion

Improvement of an artificial test substrate technique for evaluation of em immunocytochemical labeling

1987 ◽  
Vol 45 ◽  
pp. 762-763
Author(s):  
G. D. Gagne ◽  
M. F. Miller
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Artificial Substrate ◽  
Chemical Fixation ◽  
As If

We recently described an artificial substrate system which could be used to optimize labeling parameters in EM immunocytochemistry (ICC). The system utilizes blocks of glutaraldehyde polymerized bovine serum albumin (BSA) into which an antigen is incorporated by a soaking procedure. The resulting antigen impregnated blocks can then be fixed and embedded as if they are pieces of tissue and the effects of fixation, embedding and other parameters on the ability of incorporated antigen to be immunocyto-chemically labeled can then be assessed. In developing this system further, we discovered that the BSA substrate can also be dried and then sectioned for immunolabeling with or without prior chemical fixation and without exposing the antigen to embedding reagents. The effects of fixation and embedding protocols can thus be evaluated separately.

Where's That Wascally Wilber? The Challenges of Hitting a Moving Target

PsycCRITIQUES ◽  
2007 ◽  
Vol 52 (13) ◽  
Author(s):  
Douglas A. MacDonald
Keyword(s):  
Moving Target
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