Home About us Contact
|
Home About us Contact | ||
|
|
||
Recognition Accuracy (recognition + accuracy)
Selected AbstractsComplexity Analysis Based on Image-Processing Method and Pixelized Recognition of Chinese Characters Using Simulated Prosthetic VisionARTIFICIAL ORGANS, Issue 1 2010Kun Yang Abstract The influence of complexity and minimum resolution necessary for recognition of pixelized Chinese characters (CCs) was investigated by using simulated prosthetic vision. An image-processing method was used to evaluate the complexity of CCs, which is defined as the frequency of black pixels and analyzed by black pixel statistic complexity algorithm. A total of 631 most commonly used CCs that can deliver 80% of the information in Chinese daily reading were chosen as the testing database in order to avoid the negative effect due to illegibility and incognizance. CCs in Hei font style were captured as images and pixelized as 6 × 6, 8 × 8, 10 × 10, and 12 × 12 pixel arrays with square dots. Recognition accuracy of CCs with different complexity and different numbers of pixel arrays was tested by using simulated prosthetic vision. The results indicate that both pixel array number and complexity have significant impact on pixelized reading of CCs. Recognition accuracy of pixelized CCs drops with the increase of complexity and the decrease of pixel number. More than 80% of CCs with any complexity can be recognized correctly; 10 × 10 pixel array can sufficiently provide pixelized reading of CCs for visual prosthesis. Pixelized reading of CCs with low resolution is possible only for characters with low complexity (complexity less than 0.16 for a 6 × 6 pixel array and less than 0.24 for an 8 × 8 pixel array). [source] Facial emotion recognition and alexithymia in adults with somatoform disordersDEPRESSION AND ANXIETY, Issue 1 2009Francisco Pedrosa Gil M.D. Abstract Objective: The primary aim of this study was to investigate facial emotion recognition in patients with somatoform disorders (SFD). Also of interest was the extent to which concurrent alexithymia contributed to any changes in emotion recognition accuracy. Methods: Twenty patients with SFD and twenty healthy, age, sex and education matched, controls were assessed with the Facially Expressed Emotion Labelling Test of facial emotion recognition and the 26-item Toronto Alexithymia Scale (TAS-26). Results: Patients with SFD exhibited elevated alexithymia symptoms relative to healthy controls. Patients with SFD also recognized significantly fewer emotional expressions than did the healthy controls. However, the group difference in emotion recognition accuracy became nonsignificant once the influence of alexithymia was controlled for statistically. Conclusions: This suggests that the deficit in facial emotion recognition observed in the patients with SFD was most likely a consequence of concurrent alexithymia. Impaired facial emotion recognition observed in the patients with SFD could plausibly have a negative influence on these individuals' social functioning. Depression and Anxiety, 2009. © 2008 Wiley-Liss, Inc. [source] Facial emotion recognition and alexithymia in adults with somatoform disordersDEPRESSION AND ANXIETY, Issue 11 2008Francisco Pedrosa Gil M.D. Abstract The primary aim of this study was to investigate facial emotion recognition (FER) in patients with somatoform disorders (SFD). Also of interest was the extent to which concurrent alexithymia contributed to any changes in emotion recognition accuracy. Twenty patients with SFD and 20 healthy, age, sex and education matched, controls were assessed with the Facially Expressed Emotion Labelling Test of FER and the 26-item Toronto Alexithymia Scale. Patients with SFD exhibited elevated alexithymia symptoms relative to healthy controls. Patients with SFD also recognized significantly fewer emotional expressions than did the healthy controls. However, the group difference in emotion recognition accuracy became nonsignificant once the influence of alexithymia was controlled for statistics. This suggests that the deficit in FER observed in the patients with SFD was most likely a consequence of concurrent alexithymia. It should be noted that neither depression nor anxiety was significantly related to emotion recognition accuracy, suggesting that these variables did not contribute the emotion recognition deficit. Impaired FER observed in the patients with SFD could plausibly have a negative influence on these individuals' social functioning. Depression and Anxiety, 2008. © 2007 Wiley-Liss, Inc. [source] Unfamiliar face recognition in children with autistic spectrum disordersINFANT AND CHILD DEVELOPMENT, Issue 6 2009Rebecca R. Wilson Abstract We investigated unfamiliar face recognition in low-functioning children with autistic spectrum disorders (ASD) using a ,part-of-face' method. This method has not previously been used for unfamiliar faces with this population. The ,part-of-face' procedure provides measures of both face recognition accuracy and of processing style. We compared the performance of the children with ASD with three control groups: children with developmental delay (DD), typically developing (TD) children matched for verbal cognitive ability and TD children matched for chronological age (CA). Compared to the DD group, the ASD group showed similar processing in recognition accuracy and processing style. Compared to the TD children, the ASD group did not show the same level of accuracy as controls of the same CA, instead showing similar performance to younger TD children. However, as both children with ASD and DD showed the same performance, no ASD-specific deficit was found. Copyright © 2009 John Wiley & Sons, Ltd. [source] Scale and skew-invariant road sign recognitionINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2007Yi-Sheng Liu Abstract A fast and robust method to detect and recognize scaled and skewed road signs is proposed in this paper. In the detection stage, the input color image is first quantized in HSV color model. Border tracing those regions with the same colors as road signs is adopted to find the regions of interest (ROI). The ROIs are then automatically adjusted to fit road sign shape models so as to facilitate detection verification even for scaled and skewed road signs in complicated scenes. Moreover, the ROI adjustment and verification are both performed only on border pixels; thus, the proposed road sign detector is fast. In the recognition stage, the detected road sign is normalized first. Histogram matching based on polar mesh is then adopted to measure the similarity between the scene and model road signs to accomplish recognition. Since histogram matching is fast and has high tolerance to distortion and deformation while contextual information can still be incorporated into it in a natural and elegant way, our method has high recognition accuracy and fast execution speed. Experiment results show that the detection rate and recognition accuracy of our method can achieve 94.2% and 91.7%, respectively. On an average, it takes only 4,50 and 10 ms for detection and recognition, respectively. Thus, the proposed method is effective, yet efficient. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 28,39, 2007 [source] Concurrent and prospective associations between facial affect recognition accuracy and childhood antisocial behaviorAGGRESSIVE BEHAVIOR, Issue 5 2010Erica Bowen Abstract This study examined the concurrent and prospective associations between children's ability to accurately recognize facial affect at age 8.5 and antisocial behavior at age 8.5 and 10.5 years in a sub sample of the Avon Longitudinal Study of Parents and Children cohort (5,396 children; 2,644, 49% males). All observed effects were small. It was found that at age 8.5 years, in contrast to nonantisocial children; antisocial children were less accurate at decoding happy and sad expressions when presented at low intensity. In addition, concurrent antisocial behavior was associated with misidentifying expressions of fear as expressions of sadness. In longitudinal analyses, children who misidentified fear as anger exhibited a decreased risk of antisocial behavior 2 years later. The study suggests that concurrent rather than future antisocial behavior is associated with facial affect recognition accuracy. Aggr. Behav. 36:305,314, 2010. © 2010 Wiley-Liss, Inc. [source] Synthesized views can improve face recognitionAPPLIED COGNITIVE PSYCHOLOGY, Issue 7 2009Chang Hong Liu It is well known that a new face studied from one view is often difficult to identify from another. This viewpoint dependence has detrimental implications for forensic practice. To compensate for this problem, we employed synthesized face images in the training session of a standard old/new recognition task. Observers in the experimental conditions learned one or more synthesized face images along with an original photograph of the face in a different view, whereas observers in the control conditions learned only the original photograph of the face. It was found that the experimental conditions consistently produced better recognition accuracy than the control conditions. We conclude that synthesized face views can be used to facilitate person identification in forensic applications. Copyright © 2008 John Wiley & Sons, Ltd. [source] False memories for a robbery in young and older adultsAPPLIED COGNITIVE PSYCHOLOGY, Issue 2 2009Alaitz Aizpurua The aim of the present study was to analyse memory performance in young and older adults based on a robbery scenario. The study examined free recall and the recognition of actions, people and details, as well as the Remember/Know/Guess judgements that accompanied recognition. Recognition was evaluated both immediately and 1 week later, although performance was not affected by the retention interval. In the free recall task, the older adults remembered less information than the younger adults but we found no differences between the two with regard to errors. Participants accepted more false actions, thus achieving higher recognition accuracy for people and details. They also categorized false alarms for actions more often as remember than as know or guess judgements. This pattern of results was more pronounced in the older adults, suggesting that aging is an important factor in false memories for events. Copyright © 2008 John Wiley & Sons, Ltd. [source] Mazes and music: using perceptual processing to release verbal overshadowingAPPLIED COGNITIVE PSYCHOLOGY, Issue 8 2002Kimberly Finger Verbal overshadowing occurs when participants describe a previously viewed non-verbal stimulus such as a face prior to a recognition memory test. The results of numerous studies indicate that recognition accuracy is lower when participants describe the face or other non-verbal stimulus as compared to a no-description control condition. In the present two-experiment study, verbal overshadowing was alleviated when participants engaged in a non-verbal task that emphasized perceptual processing subsequent to describing the face but prior to the recognition memory test. In Experiments 1 and 2, participants viewed a face and then either described the face or completed a distractor task. Next, participants in Experiment 1 engaged in a perceptual task in the form of a series of mazes or a verbal task. Participants who described the face and completed the mazes experienced a release from verbal overshadowing as compared to participants who described the face and completed the verbal task. In Experiment 2, verbal overshadowing was alleviated when participants listened to instrumental music after describing the face, thus demonstrating that an auditory perceptual task can also release verbal overshadowing. The results of these two experiments provide support for a processing shift interpretation of verbal overshadowing. Furthermore, the results indicate this shift can be alleviated, and perceptual processing reinstated, by engaging in an unrelated perceptually oriented task such as completing a maze or listening to music. Copyright © 2002 John Wiley & Sons, Ltd. [source] Recognition of Pixelized Chinese Characters Using Simulated Prosthetic VisionARTIFICIAL ORGANS, Issue 3 2007Xinyu Chai Abstract:, The rehabilitation of the reading ability of the blind with a limited number of stimulating electrodes is regarded as one of the major functions of the envisioned visual prosthesis. This article systematically studied how many pixels of individual Chinese characters should be needed for correct and economic recognition by blind Chinese subjects. In this study, 40 normal-sighted subjects were tested on a self-developed platform HanziConvertor (Institute for Laser Medicine & Bio-photonics, Shanghai Jiaotong University, China) with digital imaging processing capacities to convert images of printed text into various pixelized patterns made up of discrete dots, and present them orderly on a computer screen. It was found that various complicated factors such as pixel number, character typeface, stroke number, etc., can obviously affect the recognition accuracy. It was also found that optimal recognition accuracy occurs at a specific size of binary pixel array, due to a trade-off between a strictly limited number of stimulation electrodes and character sampling resolution. The results showed that (i) recognition accuracy of pixelized characters is optimal with at least 12 × 12 binary pixels, and therefore it is recommended to apply a minimum of 150 discrete and functioning electrodes for restoring the reading ability of blind Chinese individuals in the visual prosthesis; (ii) fonts of Song Ti and Hei Ti are clearer and more effective than other typefaces; and (iii) characters with fewer strokes lead to better accuracy. [source] Brief exposure to a 50 Hz, 100 ,T magnetic field: Effects on reaction time, accuracy, and recognition memoryBIOELECTROMAGNETICS, Issue 3 2002John Podd Abstract The present study investigated both the direct and delayed effects of a 50 Hz, 100 ,T magnetic field on human performance. Eighty subjects completed a visual duration discrimination task, half being exposed to the field and the other half sham exposed. The delayed effects of this field were also examined in a recognition memory task that followed immediately upon completion of the discrimination task, Unlike our earlier studies, we were unable to find any effects of the field on reaction time and accuracy in the visual discrimination task. However, the field had a delayed effect on memory, producing a decrement in recognition accuracy. We conclude that after many years of experimentation, finding a set of magnetic field parameters and human performance measures that reliably yield magnetic field effects is proving elusive. Yet the large number of significant findings suggests that further research is warranted. Bioelectromagnetics 23:189,195, 2002. © 2002 Wiley-Liss, Inc. [source] Visuospatial encoding deficits and compensatory strategies in schizophrenia revealed by eye movement analysis during a working memory taskACTA NEUROPSYCHIATRICA, Issue 2 2009Luca Cocchi Objective: To investigate scanpath abnormalities during the encoding of static stimuli in schizophrenia and their interaction with visuospatial working memory (VSWM) dysfunction. Methods: Outpatients with schizophrenia and control subjects were asked to encode a static pattern for subsequent recognition after a short delay. We measured the number of correct and incorrect choices. We also assessed the number and the distribution of fixations, the scanning time in specific regions of interest (ROIs) and the head movements during the encoding of the stimuli. The distributions of fixations and scanning time in definite ROIs during the discrimination of the correct pattern from the foils were also measured. Results: Patients recognised fewer correct patterns than controls. Correct trials in patients were characterised by a specific exploration of the central part of the stimulus during its presentation, whereas this feature was absent in incorrect trials. However, the scanning time and the numbers of fixations and head movements during encoding were similar in both groups and unrelated to recognition accuracy. In both groups, correct trials were associated with a selective exploration of the correct pattern amongst the six possibilities during recognition. Furthermore, patients gave more attention to incorrect patterns with a leftmost element identical to that of the correct response and also those approximating its global structure. Conclusion: Patients showed a VSWM deficit independent of oculomotor dysfunctions and head movements during encoding. Patients' correct trials were related to specific scanning during encoding and discrimination phases. Analysis of these patterns suggests that patients try to compensate for reduced VSWM ability by using specific encoding strategies. [source] | |||||||||||||