Texture Cues Research Articles

Visual Cues in the Interpretation of Medical Images

The use of the computer in imaging has provided great versatility for the display of medical image information. In order to be useful in a medical sense, the display must be perceptually acceptable to the human observer, who must be able to extract the relevant diagnostic information from the image. Diagnostic information is defined by the imaging task, and the concept of task-dependent image quality is, therefore, very important. Visualization and estimation tasks may require different visual cues for their performance. Visualization tasks require strong boundary cues, whereas intensity estimation tasks require texture cues. Both tasks can be aided by appropriate image displays. Color can be helpful in estimation tasks, and three-dimensional display can aid visualization tasks. No matter what the task or the image, as long as an observer is needed to read out the information, performance is the final arbiter of the goodness of the image.

Integration of stereo and texture cues in the formation of discontinuities during three-dimensional surface interpolation.

A series of stereograms are presented which demonstrate that texture boundaries can strongly influence the perception of discontinuities between neighbouring three-dimensional (3-D) surfaces portrayed by means of stereo cues. In these demonstration figures, no stereo information is available in the immediate vicinity of the boundary between the two 3-D stereo surfaces because all texture in that region is removed in one eye's view. On the other hand, various forms of texture boundary information are provided in the resulting monocular region. This stimulus paradigm is used to explore the question: what influence does texture boundary information have on the nature of the perceived 3-D surface that is interpolated between two stimulus regions which carry stereo cues? It is shown that if a clear-cut texture boundary is present in the monocular region then this is used by the human visual system to fix the perceived location of 3-D crease and step surface discontinuities between the stereo regions. Collett (1985) explored this issue with a similar methodology and reported weak and unreliable assistance from monocular texture boundaries in helping shape 3-D stereo surface discontinuities. The strong and robust phenomena demonstrated here seem to rely on two main differences between the present stimuli and those of Collett. In the present stimuli, figurally continuous textures containing strong texture boundaries are used, together with a technique for minimising the complications, including binocular rivalry, that arise from the borders of the stimulus regions present in only one half of each stereogram.

Aspects of size, shape and texture in touch: redundancy and interference in children's discrimination of raised dot patterns.

Children discriminated tactual dot patterns by size or form and by texture. Adding irrelevant, easy, correlated texture cues improved size and form discrimination while orthogonal irrelevant texture cues interfered. Facilitation and interference could be reversed by reversing dimensional difficulty, but were found also when the two dimensions were equally accurate, for both blindfolded sighted and for blind children. The theoretical implication with regard to age effects, and practical implications for using dot numerosity and dot density differences for Braille learning were discussed.

Irrelevant incentive learning revisited: Associating flavors and exteroceptive cues with positive incentives

In “irrelevant incentive learning” information stored about an incentive when it is not desired is used later when the incentive is desired. In “habit learning” responses learned under one motive state continue to be made under a new motive state even though they produce goal events that are not appropriate to that motive state. Experiment 1 showed that both types of learning occur simultaneously whether flavor or texture cues are used and whether or not position is also a relevant cue. Thus, contrary to previous suggestions, irrelevant incentive learning is not limited to interoceptive cues, nor is habit learning limited to exteroceptive cues. In both Experiments 1 and 2 it was also shown that motivation affects what is learned as well as affecting current performance. This contrasts with views of motivation as solely a determinant of performance.

Pupal colour dimorphism in swallowtail butterflies: timing of the sensitive period and environmental control

ABSTRACT. Two North American swallowtail butterflies with pupal colour dimorphism, Eurytides marcellus (Cramer) and Papilio troilus L., use chiefly the colour of the pupation substrate to determine pupal colour, and are affected hardly (P.troilus) or not at all (E.marcellus) by substrate texture. The use of colour cues in these species is in contrast to the greater importance of texture in two other sympatric swallowtails (Hazel & West, 1979). E.marcellus larvae evacuate the gut and start prepupal wandering around mid‐day. If they have not reached the sensitive period for pupal colour determination by nightfall they will delay the sensitive period until the next day. Among other North American swallowtails with pupal colour dimorphism there is no tendency for those species that use textural cues for pupal colour determination to evacuate the gut later in the day than those using pupation site colour.

Nonvisual color perception: A critical review

AbstractSince the last century, there have been a number of claims that people can identify and discriminate color with their fingers. The most completely documented evidence for these claims, begining in 1963, is critically reviewed. It was the hope of the early investigators of this phenomenon that this ability would some day be useful for the blind. The best evidence suggests that people are capable of making certain temperature discriminations and that objects of different reflectances can be discriminated on this basis. The temperature exchange stems from the infrared energy emitted by the skin. Research that has presented evidence for finger color perception was often shown to have methodological problems, including learning to discriminate stimuli by texture cues and failure to adequately blindfold observers and prevent use of visual information. The present review concludes that the phenomenon of using the fingers to “see” color does not and will not, in the forseeable future, provide any additional hope for the blind.

Poison-avoidance learning to food-related tactile stimuli: Avoidance of texture cues by rats

Rats injected with lithium chloride after ingesting familiar food pellets presented in textured metal sleeves learned aversions to the sleeved food. In a choice between sleeved and unsleeved food, the aversions were evident following conditioning with toxicosis delayed as long as 120 min after exposure to the sleeved food (Experiment 1). Texture-specific aversions resulted from procedures in which rats were exposed to food in both rough- and smooth-textured sleeves but were injected with lithium only in conjunction with one of the textures (Experiments 2–4). This differential aversion learning occurred when lithium treatment was delayed 30 min after exposure to the sleeved food (Experiments 3 and 4) and was equally evident in rats conditioned and tested in total darkness or in normal room-level illumination (Experiment 4). However, differential texture aversion learning was not observed with 90- or 300-min delayed toxicosis (Experiment 3). The present experiments highlight the importance of tactile cues in the poison-avoidance learning of species that handle their food during the course of ingestion.

Visual and tactual texture perception: intersensory cooperation.

In three experiments, subjects were required to make texture judgments about abrasive surfaces. Touch and vision provided comparable levels of performance when observers attempted to select the smoothest of three surfaces, but bimodal visual and tactual input led to greater accuracy. The superiority of bimodal perception was ascribed to visual guidance of tactual exploration. The elimination of visual texture cues did not impair bimodal performance if vision of hand movements were permitted. It is suggested that touch may preempt vision when both sources of texture information are simultaneously available. The results support the notion that perception is normally multimodal, since restriction of the observer to either sense in isolation produces lower levels of performance.

Velocity blindness during shearing motion

When two objects lie at different distances from a moving observer, there is a velocity step at the occluding boundary of the nearer object. When the differential motion is tangential to the boundary, the effect is as if a shearing is taking place. If all texture cues are removed by using similar random dot patterns on each side of the boundary, then 20% of the population cannot use this differential motion to locate the boundary when it is presented to the parafovea. These observers are thus abnormally insensitive to the differential rate of texture flow at boundaries undergoing shearing motion. As no such population differences were observed for differential motion perpendicular to the occluding boundary (occluding motion), we infer that independent mechanisms process shearing and occluding motion.

Flight Simulator Runway Visual Textural Cues for Landing

The effect of visual textural patterns superimposed upon the runway touch-down zone area was studied as a potential factor in excessive vertical velocity at touchdown during flight simulation. Six simulated daytime runways with varying degrees of textural cues, as well as one night runway scene were used. The average vertical velocities at touchdown were higher in the simulator than comparable test landings in actual aircraft, but the textural cues did produce statistically significant differences in simulated vertical velocities at touchdown. Apparently the texture patterns did help to improve pilot performance, but they were not sufficient by themselves to completely solve the problem of excessive vertical velocities at touchdown.

The importance of odor and texture cues in food aversion learning

The apparent readiness of many rodent species to associate taste cues with illness has inspired some theorists to suggest that such animals are “predisposed” to acquire taste-illness associations, based upon specific adaptations of the feeding system. The present study demonstrates a reduced tendency to associate the gustatory cues of saccharin or salt with illness when alternative, olfactory cues are available, in both laboratory-bred Rattus norvegicus and second generation offspring of the cotton rat, Sigmodon hispidis. The pattern of feeding preferences expressed during two forced-choice tests may be related to the biological importance of these gustatory cues or to the evolutionary adaptation of olfactory-oriented animals to utilize the greater information-carrying capacity of the olfactory channel. Texture was also demonstrated to be important in the acquisition of food aversions. The results can best be explained in terms of cue additivity where the magnitude of a food aversion is influenced not only by the relative importance of the cues involved but also by the actual number of cues available during the choice test.

Environmental control of pupal colour in swallowtail butterflies (Lepidoptera: Papilioninae): Battus philenor (L.) and Papilio polyxenes Fabr.

Abstract. 1. Some swallowtail butterflies produce both green and brown pupae. The phenotypes result from the joint action of genotype and environment and usually make the pupae cryptic in their habitats.2. The major environmental cues influencing pupal colour in two swallowtail species were determined to be textural and optical.3. Differences in the usage of these kinds of cues in the two species are thought to have evolved because of major differences in the pupation habitats. P.polyxenes, which usually pupates on slender stems amidst vegetation, responds more strongly to optical cues. B.philenor, which usually pupates on exposed surfaces of tree trunks and cliffs, responds more strongly to textural cues.4. Differences in the overall tendency to produce brown pupae (‘sensitivity’: Hazel, 1977) are thought to be related to the frequency of brown pupation sites utilized by these two species: high average sensitivity in philenor, which often uses brown sites, and lower average sensitivity in polyxenes, which often uses green sites.

A distinctive characteristic of pictorial perception: the zoom effect.

To investigate the role of flat surface information for the plane of projection in pictorial perception, three studies were designed in which varying amounts of such information were made available to adult subjects. The first study tested preferences for true or modified linear perspective under conditions of presence or absence of surface texture cues for the plane of projection. In the second and third studies, the absence of texture cues for the plane was coupled with the addition of motion parallax and binocular information respectively. It was found that adults showed a consistent preference for parallel perspective in pictures when the flat-surface information was provided either by visible texture or by motion parallax; but no consistent preference for either true or modified perspective in the absence of all three sources of flatness information or when the flat surface information was given only by binocular cues in the absence of visible surface texture of visible surface texture or head motion.

Utilization and dominance of spatially separated cues as a function of water deprivation

Utilization and dominance of physically separate redundant-relevant cues were measured in albino rats under moderate (18 h/day) or high (23.5 h/day) water deprivation. Cues were located on goal doors (brightness) and the floor (texture) in a two-choice discrimination apparatus. Three experiments were carried out with the following paradigms: incidental cue, redundant-relevant cue discrimination, and optional shift discrimination. Deprivation did not affect rate of acquisition of initial discrimination or cue dominance. Cue utilization, however, was inversely related to deprivation in redundant-relevant cue and optional shift discrimination tasks. These effects were limited, however. Over-training on the redundant-relevant cue task eliminated the effect. Within the optional shift situation, only animals that initially acquired a texture cue discrimination were affected by deprivation. Other factors affecting cue utilization in these experiments were also described and discussed.

INDIVIDUAL DIFFERENCES IN NEONATAL PREFERENCES FOR PLANOMETRIC AND STEREOMETRIC VISUAL PATTERNS

JONES-MOLFESE, VICTORIA J. Individual Differences in Neonatal Preferences for Planometric and Stereometric Visual Patterns. CHILD DEVELOPMENT, 1972, 43, 1289-1296. The visual preferences of 20 premature and 20 fullterm neonates were measured for planometric and stereometric checkerboard patterns. The patterns were presented in pairs, and the length of fixation time to each pattern was recorded. Coombs's scaling model was applied to the data, and the results indicated no maturity differences in preference for planometric patterns that varied in amount of contour. Clear maturity differences were shown in the preferences for stereometric patterns, which differed from the planometric patterns in amount of contour, texture cues, and shading contrast. The presence of individual differences in the preferences highlighted the importance of using an individual-differences analysis. Coombs's scaling model was shown to be a useful analysis for individual-differences data.

Individual Differences in Neonatal Preferences for Planometric and Stereometric Visual Patterns

JONES-MOLFESE, VICTORIA J. Individual Differences in Neonatal Preferences for Planometric and Stereometric Visual Patterns. CHILD DEVELOPMENT, 1972, 43, 1289-1296. The visual preferences of 20 premature and 20 fullterm neonates were measured for planometric and stereometric checkerboard patterns. The patterns were presented in pairs, and the length of fixation time to each pattern was recorded. Coombs's scaling model was applied to the data, and the results indicated no maturity differences in preference for planometric patterns that varied in amount of contour. Clear maturity differences were shown in the preferences for stereometric patterns, which differed from the planometric patterns in amount of contour, texture cues, and shading contrast. The presence of individual differences in the preferences highlighted the importance of using an individual-differences analysis. Coombs's scaling model was shown to be a useful analysis for individual-differences data.

Psychophysically scaled cue differences, learning rate, and attentional strategies in a tactile discrimination task

A series of three experiments with nursery school children is reported. Texture cues, which were psychophysically scaled in the first study, were used in the following two experiments to investigate the relationship between cue differences and learning rate. It was found that psychophysically discriminable differences between cues were not used effectively in the learning situation. Except with large cue differences markedly above threshold, chance performance was obtained. The appropriateness of psychophysically scaling cues for learning studies was questioned. In addition to accuracy scores, three “attentional” exploration strategies were observed and the conditional probability of a correct response, given an appropriate attentional response, recorded. Adoption of an efficient exploration strategy led to improved performance. Thus the use of the haptic modality provided an opportunity to observe the “covert” attentional link in the learning chain and information concerning the ability of young children to adopt appropriate search strategies in a tactile discrimination task.

Tactile-vision: thermal and texture cues in the discrimination of black and white.

TEMPERATURE and texture have both been suggested as possible normal explanations of the ‘skin-vision’ phenomenon1. Neither of them explains Russian claims of perception at a distance (claims not supported by Barrett and Rice-Evans2 using a low level of illumination); however, they do provide potential cues in situations where touch is involved. Colourants may give surfaces with characteristic textures and the colour of a surface will affect the amount of heat it absorbs. Recently, Buckhout3 found that, even with illumination provided by a 40-W bulb (a good source of infrared radiation), out of 80 subjects not one could distinguish between 10 colours in 90 presentations. He controlled texture by covering the colours with a thin layer of plastic. In the experiment reported here I investigated what part both texture and temperature might play in a very simple situation: that of a black–white discrimination.

The Perception of a Changing Shape

Under specified conditions a pair of simple shapes are matched by a subject when almost all supplementary textural and space cues of depth vision have been removed. Under such conditions it is found that shape constancy is no longer present. However, the effect of regular rotatory motion of the shape is sufficient to restore constancy in the continued absence of other cues. Degree of perceptual constancy appears to be correlated with rate of change of shape. It is suggested that an explanation of the phenomenon is to be sought along the lines of Michotte's concept of “object creation” rather than in terms of gradient variables.