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Results for “Distance Perception”

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At least 19 recordsLinked to original sources
PubMed2001

The independence of size perception and distance perception.

Research on distance perception has focused on environmental sources of information, which have been well documented; in contrast, size perception research has focused on familiarity or has relied on distance information. An analysis of these two parallel bodies of work reveals their lack of equivalence. Furthermore, definitions of familiarity need environmental grounding, specifically concerning the amount of size variation among different tokens of an object. To demonstrate the independence of size and distance perception, subjects in two experiments were asked to estimate the sizes of common objects from memory and then to estimate both the sizes and the distances of a subset of such objects displayed in front of them. The experiments found that token variation was a critical variable in the accuracy of size estimations, whether from memory or with vision, and that distance had no impact at all on size perception. Furthermore, when distance information was good, size had no effect on distance estimation; in contrast, at far distances, the distances to token variable or unknown objects were estimated with less accuracy. The results suggest that size perception has been misconceptualized, so that the relevant research to understand its properties has not been undertaken. The size-distance invariance hypothesis was shown to be inadequate for both areas of research.

Adult↗
PubMed1998

The necessity of a perception-action approach to definite distance perception: monocular distance perception to guide reaching.

In this investigation of monocular perception of egocentric distance, the authors advocate the necessity of a perception-action approach because calibration is intrinsic to definite distance perception. A helmet-mounted camera and display were used to isolate optic flow generated by participants' head movements toward a target, and participants' reaches to place a stylus either in a target hole (Experiments 1, 2, and 4) or aligned under a target surface (Experiment 3) were analyzed. Conclusions are that binocular distance perception is accurate, monocular distance perception yields compression that is not eliminated by feedback, but feedback is used to eliminate underestimation generated by restriction of the size of the visual field.

Adult↗
PubMed1985

Binocular distance perception: egocentric distance tasks.

This study extends and tests a theory of binocular distance perception that has been shown to give a good account of performance in relative distance tasks. Here the theory is tested in two experiments in which the observer directly indicates perceived egocentric distance of targets (perceived distance from himself or herself) by means of a verbal report or manual pointing response. In the first, the distance to two targets is varied while maintaining a constant disparity between them. In the second, one target is held fixed while the distance to a second target is varied. In each case, the observer indicates the perceived distance of each target. Manual and verbal responses are found to agree with each other to within a linear transform. Both sets of data are shown to be consistent with the theory and are used to estimate the parameters of the theory. There is no other theory that predicts these results.

Adolescent↗
PubMed2002

Blurring of the senses: common cues for distance perception in diverse sensory systems.

Distance perception is an essential task of sensory systems. Our visual systems effectively use binocular visual cues to determine an object's distance. Other visual, but monocular, cues are also available for distance perception. Visual contrast and image blur are two such cues [O'Shea et al., 1994. Vis. Res. 34, 1595-1604; O'Shea et al., 1997. Perception 26, 599-612; Mather, 1997. Perception 26, 1147-1158]. We show the effects of combining these cues using a simple psychophysical test. The novelty in our approach is that our exact choice of visual stimuli allows us to show a direct parallel between visual distance perception and distance perception using an entirely different sense, the electric sense of weakly electric fish. We discuss previous work on electrosensory psychophysics [von der Emde et al., 1998. Nature 395, 890-894] and show that cues used for electrosensory distance perception are analogous to visual contrast and blur. We also suggest that analogous cues are involved in auditory distance perception. The utilization of analogous cues implies that these diverse sensory systems perform similar computations for distance perception.

Animals↗
PubMed2001

Distance perception within near visual space.

We investigated the perception of distance of visual targets with constant size and luminance presented between 20 and 120 cm from subjects' eyes. When retinal disparity cues were present, the subjects could reproduce very accurately the distance of a seen reference in this area. When only extraretinal information was available, distance perception was still correct for distances of 40 cm or less. However, distances beyond 60 cm were underestimated. When forced to evaluate the distance between a reference and themselves, e.g. when evaluating the absolute distance or half the distance or twice the distance of a reference, subjects used an egocentric plane of reference located on average 10.4 cm in front of their eyes. Measurements of binocular eye movements indicated a clear relationship between vergence angle and target distance. The egocentric plane of reference at 10.4 cm also corresponds to the maximum achievable vergence. These results suggest that ocular convergence can be used as a reliable cue for distance within the arm's reaching space.

Adult↗
PubMed1999

Auditory distance perception in rooms.

The perceived distance of a sound source in a room has been shown to depend on the ratio of the energies of direct and reflected sound. Although this relationship was verified in later studies, the research has never led to a quantitative model. The advent of techniques for the generation of virtual sound sources has made it possible to study distance perception using controlled, deterministic stimuli. Here we present two experiments that make use of such stimuli and we show that a simple model, based on a modified direct-to-reverberant energy ratio, can accurately predict the results and also provide an explanation for the 'auditory horizon' in distance perception. The modification of the ratio consists of the use of an integration time of 6 milliseconds in the calculation of the energy of the direct sound. This time constant seems to be important in spatial hearing-the precedence effect is also based on a similar integration window.

Auditory Perception↗
PubMed1986

Distance perception in photographic displays of natural settings.

Distance perception of depicted objects was examined as a function of photographic perspective. 24 subjects viewed slides of outdoor scenes and directly estimated the distances to specified objects. Perspective was manipulated by photographing each scene with lenses of four different focal lengths: 48 mm, 28 mm, 24 mm, and 17 mm. Distance perception along the pictorial depth plane (z-axis) was systematically transformed by changing the photographic perspective: the shorter the focal length of the camera lens, the greater the perceived distance. Perceived distance between objects along the lateral plane (x-axis) was unaffected by changes in lens focal length.

Cues↗
PubMed1989

Distance perception as a function of photographic area of view.

Distance perception of depicted objects was examined as a function of photographic area of view. Subjects viewed slides of natural outdoor scenes and directly estimated the distances to specified objects. Area of view was manipulated by means of photographing each scene with lenses of five different focal lengths: 135, 80, 48, 28, and 17 mm. Distance perception along the pictorial depth plane was systematically transformed through changing the photographic area of view: the shorter the focal length of the camera lens, the wider the area of view, and the greater the perceived distance. Linear functions for each subject's distance judgments revealed a very high goodness of fit. Both the y-intercepts and the slopes increased as focal length decreased. The increasing y-intercepts suggest that viewers place themselves farther away from the depicted scene as focal length decreases, compensating for the advancing proximal edge. The increasing slopes suggest that distance information throughout the pictorial depth plane appears to change with focal length. The subjects also made direct judgments of foreground truncation, revealing that foreground truncation decreased as focal length decreased, but that this decrease did not account for the considerable expansion in distance perception.

Adult↗
PubMed1998

Assessing auditory distance perception using perceptually directed action.

Three experiments investigated auditory distance perception under natural listening conditions in a large open field. Targets varied in egocentric distance from 3 to 16 m. By presenting visual targets at these same locations on other trials, we were able to compare visual and auditory distance perception under similar circumstances. In some experimental conditions, observers made verbal reports of target distance. In others, observers viewed or listened to the target and then, without further perceptual information about the target, attempted to face the target, walk directly to it, or walk along a two-segment indirect path to it. The primary results were these. First, the verbal and walking responses were largely concordant, with the walking responses exhibiting less between-observer variability. Second, different motoric responses provided consistent estimates of the perceived target locations and, therefore, of the initially perceived distances. Third, under circumstances for which visual targets were perceived more or less correctly in distance using the more precise walking response, auditory targets were generally perceived with considerable systematic error. In particular, the perceived locations of the auditory targets varied only about half as much in distance as did the physical targets; in addition, there was a tendency to underestimate target distance, except for the closest targets.

Auditory Perception↗
PubMed2005

The influence of restricted viewing conditions on egocentric distance perception: implications for real and virtual indoor environments.

We carried out three experiments to examine the influence of field of view and binocular viewing restrictions on absolute distance perception in real-world indoor environments. Few of the classical visual cues provide direct information for accurate absolute distance judgments to points in the environment beyond about 2 m from the viewer. Nevertheless, in previous work it has been found that visually directed walking tasks reveal accurate distance estimations in full-cue real-world environments to distances up to 20 m. In contrast, the same tasks in virtual environments produced with head-mounted displays (HMDs) show large compression of distance. Field of view and binocular viewing are common limitations in research with HMDs, and have been rarely studied under full pictorial-cue conditions in the context of distance perception in the real-world. Experiment 1 showed that the view of one's body and feet on the floor was not necessary for accurate distance perception. In experiment 2 we manipulated the horizontal and the vertical field of view along with head rotation and found that a restricted field of view did not affect the accuracy of distance estimations when head movement was allowed. Experiment 3 showed that performance with monocular viewing was equal to that with binocular viewing. These results have implications for the information needed to scale egocentric distance in the real-world and reduce the support for the hypothesis that a limited field of view or imperfections in binocular image presentation are the cause of the underestimation seen with HMDs.

Adult↗
PubMed1999

Some recent studies on the extraretinal contribution to distance perception.

Some recent studies on the extraretinal contribution to distance perception are reviewed. These experiments demonstrate that vergence can provide reliable information for judgments on the distance of proximal targets in the absence of all other cues. We argue that, although vergence is an unreliable cue at large fixation distances and is subject to a strong contraction bias when studied in isolation, these facts do not imply a minor role for vergence in near-space perception. When additional depth and distance cues are added, the contribution of vergence information becomes more complicated. We present results which indicate that the different cues to depth and distance are combined in a manner that can result in unexpected distortions of visual space. A simple heuristic model which can produce the observed distortions is outlined.

Accommodation, Ocular↗
PubMed1980

Accommodation, convergence, and distance perception in low illumination.

The role of oculomotor adjustments for distance perception in dim light was investigated while preserving the natural interactions between accommodation and convergence. The results show that perceived distance in the dark is biased toward an intermediate value that is correlated with the vergence adjustment assumed in darkness but unrelated to the dark focus of accommodation. A subsequent experimient showed that short-term adaptation to base-out prisms and negative lenses of corresponding strength affects perceived distance and dark convergence but has no influence on the dark focus of accommodation. These findings were interpreted as indicating that convergence is a more important distance cue than accommodation under low illumination and that the physiological resting states of convergence and accommodation are relatively independent.

Accommodation, Ocular↗
PubMed1998

Comparing measures of monocular distance perception: verbal and reaching errors are not correlated.

Monocular perception of egocentric distance via optic flow generated by head movement toward a target was investigated with a helmet-mounted video camera and display. Ability to perceive target distance was assessed with 2 response measures: verbal reports and reaches. Systematic and random errors differed as a function of the response measure. Verbal estimates of targets within and beyond reach were obtained before and after the performance of reaches to targets within reach. Systematic errors of verbal estimates changed but did not decrease overall. Random error decreased. Verbal estimates and reaches were performed concurrently to targets within reach. Verbal and reaching errors were uncorrelated. Verbal judgments appear to have been anchored using the range of distances experienced while reaching rather than being calibrated to the perceptual information itself. Discussion focuses on the advantages of action response measures.

Adult↗
PubMed1994

Convergence responses to monocularly viewed objects: implications for distance perception.

In four experiments the role of dark vergence and the implied distance from the familiar-size and suggested-size cues to distance on the convergence response was investigated. A nonius-alignment technique was used to measure the convergence response in total darkness (dark vergence) and the fusion-free convergence response to monocularly viewed objects presented at a distance of 75 cm under otherwise reduced stimulus conditions. Observers also estimated the size and distance of the objects. The results indicated a significant association between individuals' dark-vergence distances and the convergence distances to the objects. Furthermore, the convergence response was influenced by the implied distance from the familiar-size cue but not by the implied distance from size suggestions. Both the familiar-size and the suggested-size cues influenced reports of distance. The implications of these findings for distance perception are discussed with particular reference to the familiar-size cue to distance.

Adult↗