Figure Discrimination Research Articles

Development of the attachment bond in guide dogs

This study investigates ontogenetic aspects of attachment behaviour in guide dogs using the Strange Situation Test (SST). Seventeen dogs were tested three times in different periods of the guide dog training program. The first test was carried out when the dogs were 11–15 months old and before entering the training program; the second test took place after 4 months of training; the last test was carried out after more than 1 year of service as guide dogs. Therefore three different human figures were involved in the program: the puppy walker, the trainer and the blind owner. In each test the dogs’ behaviour was video recorded and subsequently scored using a 5-s point sampling method; furthermore heart rate (HR) was recorded both before (HR basal average) and during the SST. Results of the present study show that when tested for the first time at the age of 11 months, dogs exhibited an intense play activity and a limited discrimination of the attachment figure: during separation from the puppy walker their attention was directed towards the stranger that could offer comfort rather than to the owner's exit from the room. On the contrary, the same dogs tested when adult, after 1 year of life with the blind owner were specifically interested in regaining contact with their owner despite the presence of another friendly human (the stranger) available for support. The three repetitions of the SST had only a limited impact on dogs behaviour: previous experiences with the room and the procedure of the test did determine a decrease of exploratory behaviour and of puppet fear, but not of the emotional response to separation from the owner. As the heart rate curve was available only for a limited number of dogs cautious conclusions are drawn on cardiac activity: when adult, dogs showed a higher cardiac activation despite a decrement in HR baseline. Overall, the outcome of the present study indicate that a full-fledged attachment is showed when guide dogs reach maturity and that repeated bond breaking is not detrimental to forming attachment later in life.

Training and oblivion characteristics of modulated vibration stimulus

AbstractThe purpose of this study is tactile presentation of figure information by means of modulated vibration based on a short‐cycle component Ts−1 (40 to 1000 Hz) and a long‐cycle component Tl−1 (2 to 40 Hz). An effective method for training of the modulated vibration stimulus is proposed and the experimental results on the training and oblivion characteristics of figure discrimination are presented. A training method that integrates tactile and visual stimuli is found to be effective, and it is shown that the association with the frequency change of the long‐cycle component is retained in memory longer than that of the short‐cycle component. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(4): 27– 33, 2008; Published online in Wiley InterScience(www.interscience.wiley.com). DOI 10.1002/ecj.10078

Rapid Detection of Person Information in a Naturalistic Scene

A preferential-looking paradigm was used to investigate how gaze is distributed in naturalistic scenes. Two scenes were presented side by side: one contained a single person (person-present) and one did not (person-absent). Eye movements were recorded, the principal measures being the time spent looking at each region of the scenes, and the latency and location of the first fixation within each trial. We studied gaze patterns during free viewing, and also in a task requiring gender discrimination of the human figure depicted. Results indicated a strong bias towards looking to the person-present scene. This bias was present on the first fixation after image presentation, confirming previous findings of ultra-rapid processing of complex information. Faces attracted disproportionately many fixations, the preference emerging in the first fixation and becoming stronger in the following ones. These biases were exaggerated in the gender-discrimination task. A tendency to look at the object being fixated by the person in the scene was shown to be strongest at a slightly later point in the gaze sequence. We conclude that human bodies and faces are subject to special perceptual processing when presented as part of a naturalistic scene.

Comparison between Figure Discrimination and Color Discrimination by Hue Differences of Multi-colored Regions with Saturation Distributions

Comparison between Figure Discrimination and Color Discrimination by Hue Differences of Multi-colored Regions with Saturation Distributions

変調振動刺激に対する学習および忘却特性

The purpose of this study is tactile presentation of figure information by means of modulated vibration based on a short-cycle component Ts−1 (40 to 1000 Hz) and a long-cycle component Tl−1 (2 to 40 Hz). An effective method for training of the modulated vibration stimulus is proposed and the experimental results on the training and oblivion characteristics of figure discrimination are presented. A training method that integrates tactile and visual stimuli is found to be effective, and it is shown that the association with the frequency change of the long-cycle component is retained in memory longer than that of the short-cycle component. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(4): 27– 33, 2008; Published online in Wiley InterScience(www.interscience.wiley.com). DOI 10.1002/ecj.10078

Topographic change in ERP due to discrimination of geometric figures in the peripheral visual field

The present study examined the neurophysiological aspects of discrimination of geometric figures with different eccentricities. In the behavioral experiment, a circle and 3 geometric polygons (square, hexagon, or octagon) were presented for 300 ms at quadrant locations. The eccentricity was changed from 2° to 16° at 2° intervals. The participants (10 adults) were instructed to fixate the center of the CRT and find the circle among the polygons. In the neurophysiological experiment, 4 identical stimuli (squares, hexagons, octagons, or circles) were presented at an eccentricity of 4°, 8°, or 12°. Discrimination performance in the periphery declined when the angularity of the polygons increased. ERP components at 80 ms (P1 with posterior positivity) and 140 ms (N1 with posterior negativity) were observed regardless of the eccentricity or shape of the stimuli. N1 lasted longer as eccentricity increased. P2 with posterior positivity at 200 ms became blurred in the periphery, except for squares. The topography of N1 and P2 changed, depending on the retinal stimulus location; it was influenced by the angularity of the geometric figures in the peripheral visual field. Cerebral processing concerned with N1 and P2 might play an important role in the perception and recognition of visual objects in the peripheral visual field.

RENOVANDO A TRADIÇÃO PELOS CAMINHOS DA INTERTEXTUALIDADE

The re-writing or misreading of fairy tales and other canonic texts by Angela Carter, Stevie Smith, Liz Lochhead and Anne Sexton show a peculiar deconstruction/reconstruction of male narrative which proposes a new literary form to the texts, and a new voice to the feminine role. Through the diegetic transposition and parody, many elements present in fairy tales and other canonic texts pass through a transvalorization of axiological nature of its first cultural horizon and meaning. That re-writing also occurs on the linguistic level and on superficial structures without never loose the intertextual relationship to the original text, questioning prejudices and discrimination of the feminine figure. This kind of re-writing tries to demonstrate that women are creating a literature of their own where feminine stories are narrated by the point of view of women. Transcending the dichotomic system of genre that always has produced secular and historical relations of male power, the feminist writing reconstructs the concept of difference between human beings, causing the rupture of the hegemonic male discourse, giving new meaning to the concept of culture. Otherwise, we can observe that the first aim of those rewritings in not merely destroy a tradition that perpetuate myths and patriarchal ideals, but to show its limits, their crevices, in order to allow the renew of the tradition, satisfying the double necessity of revision and continuity in relation to the past, recurring to the wide path of intertextuality.

Comments on “ground from figure discrimination”

Two techniques for extracting foreground edges from an edge map are quantitatively tested and compared. Although Amir and Lindenbaum’s algorithm (Comput. Vision and Image Understanding 76 (1) (1999) 7) and Venkatesh and Rosin’s algorithm (Comput. Vision Graphics Image Process. 57 (2) (1995) 146) operate on very different principles it is shown that their results or of similar quality. The advantage of Venkatesh and Rosin’s algorithm is that it is computationally more efficient and does not require tuning parameters.

The hole precedence in face but not figure discrimination and its neuronal correlates

The discriminative tasks of face and geometrical figure were trained in three rhesus monkeys. The hole feature speeds up learning of face discrimination, but hampers learning of figure discrimination. By reducing presentation duration of the stimuli, the detecting precedence appears to be the hole feature of the face component, while it appears to be shape feature of figures. The patterns of neuron firings in inferior temporal cortex (IT) are consistent with the context-dependent precedence of hole feature. The results might suggest that the neural correlates exist not only in IT neurons, but also in combination with executive mechanism.

Response to Contrast Objects of the Seven-Spot Ladybird Coccinella septempunctata (Coleoptera, Coccinellidae)

The goal of the work was to establish whether the seven-spot ladybird Coccinella septempunctata has a spatial constancy towards the shape of images. The beetles were presented with black figures on the white wall of the cylindrical arena. The beetles were walking with different orientation of the body relative to the force of gravity: in the horizontal plane, on a three-ray labyrinth or on the flat ring in the bottom of the arena; with an inclination of 90° on the cylindrical ring wall; upwards on the vertical labyrinth or upside down, under a thin wire labyrinth stretched over the arena. The beetles in the horizontal position did not discriminate from each other differently orientated images, except for two types of the figures: vertical or horizontal bands (the choice was 80:20%) and meanders orientated downwards and upwards (the choice was 56:44%). The bands oriented vertically towards the Earth were preferred by the beetles when observed from the inclination position, but not in the case of a vertical ascension. The meanders were not discriminated when observed from the upside down position. The ascending oblique bands were preferred over the descending ones. No ability to discriminate the shape of objects was found in the ladybirds, and, correspondingly, they have no spatial constancy. The discrimination of figures and ornaments has the simplest mechanism: detection of the movement (directional) of a contrast margin.

A model of adaptive visual processes of primary image processing.

A computer model of adaptive segmentation of two-dimensional visual objects was developed, based on neurophysiological and psychophysiological principles. The model imitates several stages of visual information processing. At the first stage, a preliminary assessment of the image is performed using a brightness pattern analyzer. At the second stage, control parameters are formed on the bases of the initial assessment. A defined control vector is synthesized for each type of starting image, which allows adaptive processing; this initiates two parallel mechanisms of primary image description: one contains the outlines of images and the sharp boundaries between their fragments, and the second contains areas of uniform intensity. The control parameter vector is applied to these two descriptions to analyze their brightnesses and spatial characteristics, and this is used as the basis for forming the regime for subsequent processing, which includes a set of processing operators whose parameters are tuned for each fragment of the image. The primary phasic and tonic descriptions are then used to extract individual fragments of the image (i.e., discrimination of figures from the background) and to form the final presentation. The resulting descriptions complement each other, creating a basis for quantitative measurements of image characteristics and allowing various signs needed for image classification to be formed. The computer program for adaptive image segmentation was tested using a large number of different two-dimensional half-tone objects, the purposes of these exercises including segmentation and measurement of objects in morphometric and cytometric studies.

Ground from Figure Discrimination

This paper proposes a new, efficient, figure from ground discrimination method. This algorithm is based on the assumption that background data features can be more easily detected than figure data features, thus emphasizing the background detection task (and implying the name of the method). Along the iterative labeling process, data features are sequentially and permanently labeled as “background,” while more global information is being collected to assist with the coming decisions, until the process converges. This procedure creates a bootstrap mechanism which improves performance in very cluttered scenes. The method can be applied to many perceptual grouping cues, and an application to smoothness-based classification of edge points is given. A fast implementation using a kd-tree allows one to work on large, realistic images.

Discrimination of multidimensional geometrical figures by chickens: categorization and pattern-learning

Japanese bantam hens were trained to discriminate between geometrical figures varying along four integral dimensions. Only one dimension predicted food: selections of sharp-cornered figures were reinforced, while selections of rounded figures were not. In experiment 1, hens were subsequently trained to discriminate between nine figure pairs in a simultaneous discrimination task. Because single pairs contained multiple redundant cues, whereas the relevant dimension was obvious only across stimulus pairs, the results revealed effects of both generalization and reversal learning. Accordingly, learning speed was enhanced for later discriminations. Experiment 2 tested the hens’ transfer performance to unknown pairs, following experience of 9 or 18 figure pairs. Four of seven hens showed reliable transfer after experience with 9 figures, but only three showed transfer after experience with 18 figures, indicating lower transfer with higher number of stimulus pairs learned. In experiment 3, hens were trained to discriminate 27 figure pairs. Discrimination ratios further decreased and the groups of pairs differed significantly in their ratios of discrimination. Individual hens’ pecking behaviour was analysed in relation to each dimension of single figures and in relation to relative differences in the levels of dimensions between paired figures. Hens were shown to be oriented towards irrelevant information and more towards relational and configurational than elemental and dimensional aspects. The results are discussed in the biological context of individual recognition in chickens’ dominance hierarchies, in which we suppose that chickens identify individual flock mates by representation of their visual pattern rather than by single characteristics.

精神遅滞者における幾何学図形検出時の有効視野

精神遅滞者における幾何学図形検出時の有効視野

ERP evoked by geometric figure discrimination task presented inside or outside the useful visual field

ERP evoked by geometric figure discrimination task presented inside or outside the useful visual field

Effects of a static textured background on motion integration

We studied how the visual system integrates locally ambiguous velocities into global unambiguous coherent motion in the presence or absence of a textured background. Line drawings of complex figures were presented through invisible (i.e. same luminance and hue as the background) circular apertures such that only straight line segments were visible. These figures were either presented against a uniform background or embedded in static textures made of similar line segments in such a way that figures cannot be detected if they remain static. Under our experimental conditions, the figures translated clockwise or counterclockwise along a circular path and observers were required to discriminate the global direction of motion. Because of the aperture problem, a single moving segment cannot disambiguate the global direction of the figures and integration across multiple line segments is therefore necessary to perform the task. We found that with figures at high contrast, the presence of a texture enhanced direction discrimination, while direction discrimination of figures at low contrast was impaired by the presence of the texture. These paradoxical effects of a static texture were further tested by manipulating the relative contrast between figures and texture, the motion onset asynchrony (the delay between stimulus onset and motion onset or MOA), the density, the orientation and the distribution of texture elements. The effects of the texture, either facilitation or suppression, increase with texture contrast. Accuracy improves with MOA and decreases with texture density. In general, at high figure contrast, accuracy is better whenever referents are present in the image. We suggest that facilitation by the texture at high figure contrast is accounted for by reduced salience of segmentation cues such as line terminators and increased accuracy of local velocity measurements. On the other hand, decreased performance at low figure contrast may reflect lateral suppression of the responses to motion signals by the texture

幾何学図形定位と弁別におけるサッケイド関連電位

左右15。に呈示された幾何学図形 (円・四角形・八角形) 追視時のサッケイド関連電位を検討した.大学生8名を対象に頭皮上8部位から脳波を導出した.中央の凝視点が消えると同時に呈示された図形追視条件 (NON-TARGET条件) と, 呈示図形が円の場合にボタン押しをする条件 (TARGET条件) についてサッケイド終了時点にあわせて加算波形を求めた.ラムダ反応はいずれの条件でも左後頭部よりも右後頭部で振幅が大きかった.TARGET条件では, 円と八角形弁別時に200ms前後に陰性成分の出現が認められた.また, 300ms以降に陽性成分の出現が認められ, 四角形よりも弁別の難易度が高い八角形でその潜時は延長していた.これらの結果から図形弁別の過程がサッケイド関連電位に反映されていることが示唆された.

The role of features in preattentive vision: Comparison of orientation, motion and color cues

Arrays of lines or blobs were used to investigate the role of features vs feature contrast in preattentive vision. This study continues earlier work on orientation cues and extends it into the dimensions of motion and color. Tests were performed on patterns displaying continuous feature gradients, i.e. continuous variation, from element to element, in either line orientation, direction of motion, or color. In different series of experiments, the following four aspects of visual perception were investigated: (i) detection of a salient target (“odd man out” paradigm), (ii) segmentation of texture fields, (iii) search strategies for given targets, and (iv) figure-ground discrimination by grouping. Features were, in general, not found to play an important role in these tasks and performance was instead related to feature contrast. Only in the case of color did performance also depend upon hue, i.e. feature properties themselves. Whereas in all dimensions tested pop-out (“saliency”) and segmentation were obtained from target or border elements whose local feature contrast was well above the level of variation elsewhere in the pattern, performance in the two latter tasks differed between orientation, motion, and color. In search, orientation targets were detected quickly when sufficiently distinct from their neighbors, but were apparently searched for serially if feature contrast was similar to that of other elements nearby. Color targets, however, were always detected fast in these patterns, independently of local feature contrast. Also, the perceived grouping of orientation or motion defined targets depended only on local feature contrast and not on the similarity of target elements. In fact, figures of dissimilar elements were seen as easily as figures of similar elements, indicating that, in these dimensions, stimulus coherence is not essential for the discrimination of figure and ground. For color, however, figures made up of the same targets were always seen slightly better than figures composed of different colors.

Visual discrimination of discontinuous figures in the rabbit

Rabbits were trained to discriminate between vertical and horizontal striations. After the 90% correct level had been reached transfer to vertical and horizontal rows of dots was studied. It was found that performance depended on the distance between adjacent dots. With angular dot separations (measured from the centers) larger than 4.9°, performance was below the 75% correct level. This result is discussed in relation to the size of the receptive fields of orientation-selective neurons in the binocular visual cortex.

Discrimination of facial components in autistic children

A simultaneous face discrimination learning task was given to 15 autistic children and 14 normal controls. Face stimuli were presented in the form of schematic line drawing. After attaining discrimination, their responses to facial components, namely, color, expression and orientation (upright or inverted), were tested. The autistic group more frequently responded incorrectly to orientation than to the other two components. Moreover, the response latencies to all the three components were shorter in the autistic group than in the normal group. Using the same experimental procedure, a figure discrimination learning task was given to other groups of autistic and normal children. The results indicated no significant differences between the autistic and normal groups in either the rate of correct responses or the latency to figure components. These results were interpreted to suggest that the autistic children recognized face stimuli only in terms of component properties.