Restricted posed fish category recognition based on contour curvature

We propose a novel approach to generate intermediate contours given a sequence of object contours. The proposal unifies shape features through contour curvature analysis and motion between the contours through optic flow analysis. The major contribution of this work is in integrating this shape and image intensity-based contour interpolation scheme in a level-set framework. The interpolated contours between an initial and a target contour act as missing link and establish a path along which contour deformation has taken place. We have shown that for different application domains such as 3D organ visualization (the generation of contours between two spatially apart contours of 2D slice images of a 3D organ), the meteorological applications of tracing, and the path of a developing cyclone (when satellite images are taken at distant time points and the shape of cyclone in between two consecutive satellite images are of interest), the proposal has outperformed the competing approaches.

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Noise Analysis and Filtering for Laser Active Imaging System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.475-476.282 ◽

2013 ◽

Vol 475-476 ◽

pp. 282-286

Author(s):

Tao Sun

Keyword(s):

Imaging System ◽

Noise Analysis ◽

Speckle Noise ◽

Recognition System ◽

Denoising Method ◽

Edge Information ◽

System A ◽

Active Imaging ◽

The Difference ◽

Contour Curvature

In order to deal with the contradiction between suppressing speckle noise and reserving details in laser active imaging recognition system, a denoising method based on contour curvature is proposed. Due to the contour curvature, the pixels in the image are divided into different classes, which contain different amount of information. The filter parameters are different for each class. Firstly, the origin image is smoothed using wavelet soft thresholding, then the contours are extracted by Morphological edge detection operator. Due to the difference of contour curvature, the pixels are labeled with point of strong signal, point of weak signal or point of no signal. Pixels with different labels are filtered by Lee filter of different step width. Experiment result indicates that compared with classical Lee filter, the proposed method performs better in filtering and keeping edge information.

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Mid-level Priming by Completion vs. Mosaic Solutions

i-Perception ◽

10.1177/2041669518820347 ◽

2019 ◽

Vol 10 (2) ◽

pp. 204166951882034 ◽

Cited By ~ 3

Author(s):

Antonio Peta ◽

Carlo Fantoni ◽

Walter Gerbino

Keyword(s):

Image Segmentation ◽

Mirror Symmetry ◽

Matching Task ◽

Structural Factors ◽

Prime Duration ◽

Fixation Cross ◽

Prime Sequence ◽

Matching Performance ◽

Contour Curvature

We report two experiments on the role of mid-level processes in image segmentation and completion. In the primed matching task of Experiment 1, a cue→prime sequence was presented before the imperative stimulus consisting of target shapes with positive versus negative contour curvature polarity and one versus two axes of mirror symmetry. Priming shapes were included in two composite occlusion displays with the same T-junction information and different geometric features supporting a distinct balance between completion and mosaic solutions. A cue, either congruent or incongruent with targets, preceded the presentation of the composite priming display. Matching performance was affected by primes in the expected direction, while cue congruency participated only in a marginally significant three-way interaction, and prime duration had no effect. In Experiment 2, the cue→prime sequence was replaced by a fixation cross to control for the priming effect obtained in Experiment 1. The study confirmed that contour connectability and curvature polarity are effective structural factors capable of competing with symmetry in mid-level image segmentation and completion processes.

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Limited Capacity for Contour Curvature in Iconic Memory

Perceptual and Motor Skills ◽

10.2466/pms.102.3.611-631 ◽

2006 ◽

Vol 102 (3) ◽

pp. 611-631 ◽

Cited By ~ 1

Author(s):

Koji Sakai

Keyword(s):

Iconic Memory ◽

Limited Capacity ◽

Contour Curvature

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The cue for contour-curvature discrimination

Vision Research ◽

10.1016/0042-6989(93)90089-f ◽

1993 ◽

Vol 33 (3) ◽

pp. 329-341 ◽

Cited By ~ 22

Author(s):

David H. Foster ◽

David R. Simmons ◽

Malcolm J. Cook

Keyword(s):

Contour Curvature

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Capacity Limitation in Short-Term Visual Memory for Contour Curvature

Perception ◽

10.1068/p3365 ◽

2005 ◽

Vol 34 (9) ◽

pp. 1095-1105 ◽

Cited By ~ 3

Author(s):

Koji Sakai

Keyword(s):

Size Effect ◽

Visual Memory ◽

Weber Fraction ◽

Short Exposure ◽

Difference Threshold ◽

Short Term ◽

Capacity Limitation ◽

Set Size ◽

Short Term Visual Memory ◽

Contour Curvature

I measured the difference threshold for contour curvature in short-term visual memory (STVM) using a two-interval forced-choice partial discrimination task. In experiments 1 and 2, the study stimulus consisting of 1 to 4 curved contours was briefly presented. It was followed by a single contour stimulus after a retention interval. The subjects judged if the test stimulus had a higher or lower curvature than the corresponding study contour. The results of experiment 1 showed that the Weber fraction increased monotonically with increasing set size. The results of experiment 2 clarified that the set-size effect was not due to a temporal limitation in encoding resulting from the short exposure time. In experiment 3, the study stimuli always consisted of 4 items, but the numbers of memorised items were different in each condition. Nevertheless, the results showed the set-size effect, which indicated that its occurrence depended largely on the capacity limitation in short-term visual memory (STVM) storage. Otherwise, the Weber fraction was not hugely higher for set size 4 compared with set size 1. It was concluded that only 1 object could be retained in STVM with high fidelity, but that at least 4 objects could be retained in STVM with some degree of fidelity.

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