Effects of Optical Flow and Discrete Warnings on Deceleration Detection during Car Following

2005 ◽  
Vol 49 (17) ◽  
pp. 1673-1676 ◽  
Author(s):  
Patricia R. DeLucia ◽  
Anand Tharanathan
Keyword(s):  
Optical Flow ◽  
Collision Avoidance ◽  
Critical Value ◽  
Optical Parameters ◽  
Warning Systems ◽  
Time To Contact ◽  
Future Studies ◽  
Car Following ◽  
Deceleration Rate ◽  
Flow Information

Tau specifies time-to-contact between a driver and a lead car, and is potentially useful to prevent rear-end collisions. However, studies suggest that time-to-contact judgments are based on multiple information sources and that effective information varies with distance. We focused on three questions: Does a driver's response to a lead car's deceleration occur when the car's optical size, expansion rate, or tau reaches a “critical” value? Does effective information differ for near and far lead cars? Is a driver's response affected by discrete warnings (brake lights and auditory warnings) that occur independently of optical flow information? Results suggested that responses were not based on a critical value of the optical parameters considered here, and were affected by discrete warnings. Further, effective information varied with the distance and deceleration rate of the lead car. Results were consistent with prior proposals that advanced brake warning systems and collision-avoidance warning systems can reduce the incidence of rear-end collisions. Future studies of this kind will help to improve the design of collision-avoidance systems and to reduce rear-end collisions.

Detecting the Deceleration of a Lead Car during Active Control of Virtual Self Motion

2007 ◽  
Vol 51 (24) ◽  
pp. 1522-1525 ◽  
Author(s):  
Anand Tharanathan ◽  
Patricia R. DeLucia
Keyword(s):  
Collision Avoidance ◽  
Active Control ◽  
Traffic Accidents ◽  
Warning Systems ◽  
Mean Response Time ◽  
Traffic Conditions ◽  
Deceleration Rate ◽  
Virtual Self ◽  
Passive Viewing ◽  
Self Motion

Twenty-five percent of traffic accidents involve rear-end collisions. One important factor that may contribute to such collisions is a driver's ability to detect the deceleration of a lead car. Prior studies of deceleration judgments involved passive viewing rather than active control of self motion. The primary purpose of this study was to measure effects of headway and deceleration rate on the detection of deceleration during (simulated) active control. We investigated whether the pattern of such effects was similar to those we reported previously for passive viewing. Consistent with our previous study, the current results indicated that, during active control, mean response time to detect deceleration was longer when headway was relatively far or when deceleration rate was relatively slow. The implication is that collision-avoidance warning systems may have to utilize different criteria for providing warnings under different traffic conditions.

TIME-TO-CONTACT INFORMATION ESTIMATION FOR MONOCULAR MOBILE ROBOTS

2008 ◽  
Vol 05 (03) ◽  
pp. 223-233 ◽  
Author(s):  
RONG LIU ◽  
MAX Q. H. MENG
Keyword(s):  
Mobile Robots ◽  
Optical Flow ◽  
Active Contour Model ◽  
Visual Navigation ◽  
Moving Object ◽  
Time To Contact ◽  
Temporal Derivative ◽  
Novel Method ◽  
Derivatives Of ◽  
Flow Experiments

Time-to-contact (TTC) provides vital information for obstacle avoidance and for the visual navigation of a robot. In this paper, we present a novel method to estimate the TTC information of a moving object for monocular mobile robots. In specific, the contour of the moving object is extracted first using an active contour model; then the height of the motion contour and its temporal derivative are evaluated to generate the desired TTC estimates. Compared with conventional techniques employing the first-order derivatives of optical flow, the proposed estimator is less prone to errors of optical flow. Experiments using real-world images are conducted and the results demonstrate that the developed method can successfully achieve TTC with an average relative error (ARVE) of 0.039 with a single calibrated camera.

scholarly journals Ghost-removal image warping for optical flow estimation

2019 ◽  
Vol 277 ◽  
pp. 02002
Author(s):  
Song Wang ◽  
Zengfu Wang
Keyword(s):  
Optical Flow ◽  
Image Warping ◽  
Estimation Methods ◽  
Flow Estimation ◽  
Optical Flow Estimation ◽  
Flow Information ◽  
Ghosting Artifacts ◽  
Compensation Technique ◽  
Image Compensation ◽  
Traditional Image

Traditional image warping methods used in optical flow estimation usually adopt simple interpolation strategies to obtain the warped images. But without considering the characteristic of occluded regions, the traditional methods may result in undesirable ghosting artifacts. To tackle this problem, in this paper we propose a novel image warping method to effectively remove ghosting artifacts. To be Specific, when given a warped image, the ghost regions are firstly discriminated using the optical flow information. Then, we use a new image compensation technique to eliminate the ghosting artifacts. The proposed method can avoid serious distortion in the warped images, therefore can prevent error propagation in the coarse-to-fine optical flow estimation schemes. Meanwhile, our approach can be easily integrated into various optical flow estimation methods. Experimental results on some popular datasets such as Flying Chairs and MPI-Sintel demonstrate that the proposed method can improve the performance of current optical flow estimation methods.

scholarly journals Optical Flow Sensor/INS/Magnetometer Integrated Navigation System for MAV in GPS-Denied Environment

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Chong Shen ◽  
Zesen Bai ◽  
Huiliang Cao ◽  
Ke Xu ◽  
Chenguang Wang ◽  
...  
Keyword(s):  
Optical Flow ◽  
Navigation System ◽  
Low Cost ◽  
Integrated Navigation ◽  
Static State ◽  
Integrated Navigation System ◽  
Microaerial Vehicles ◽  
Flow Information ◽  
Optical Flow Sensor ◽  
Navigation Scheme

The drift of inertial navigation system (INS) will lead to large navigation error when a low-cost INS is used in microaerial vehicles (MAV). To overcome the above problem, an INS/optical flow/magnetometer integrated navigation scheme is proposed for GPS-denied environment in this paper. The scheme, which is based on extended Kalman filter, combines INS and optical flow information to estimate the velocity and position of MAV. The gyro, accelerator, and magnetometer information are fused together to estimate the MAV attitude when the MAV is at static state or uniformly moving state; and the gyro only is used to estimate the MAV attitude when the MAV is accelerating or decelerating. The MAV flight data is used to verify the proposed integrated navigation scheme, and the verification results show that the proposed scheme can effectively reduce the errors of navigation parameters and improve navigation precision.

scholarly journals A situation-aware collision avoidance strategy for car-following

2018 ◽  
Vol 5 (5) ◽  
pp. 1012-1016 ◽  
Author(s):  
Li Li ◽  
Xinyu Peng ◽  
Fei-Yue Wang ◽  
Dongpu Cao ◽  
Lingxi Li
Keyword(s):  
Collision Avoidance ◽  
Car Following ◽  
Avoidance Strategy

The study of proventricular micromorphological characterization of ten Grylloidea species (Orthoptera: Grylloidea) from China

Zootaxa ◽  
2011 ◽  
Vol 2906 (1) ◽  
pp. 52
Author(s):  
XIAOQIANG LI ◽  
BINGZHONG REN ◽  
YUTING ZOU ◽  
JIAN ZHANG ◽  
YINLIANG WANG
Keyword(s):  
Electron Microscopy ◽  
Clustering Analysis ◽  
Feeding Habits ◽  
Critical Value ◽  
Morphological Characterization ◽  
Species Relationships ◽  
Future Studies ◽  
Selection Of ◽  
Scanning Electron

The present study compares the proventricular morphology, analyzed under optic microscope and scanning electron microscopy (SEM), among ten Grylloidea species. The result showed that the size of proventriculus was of critical value. Internally, the main differences were the number of sclerotized appendix (sa), middle denticles (md) and lateral denticles (ld), and the structure of lateral teeth (lt). In addition, we analyzed the crickets’ feeding habits and note that the the proventriculus possesses highly sclerotized projections which act in the selection of victuals. The morphology of proventriculus is closely related to feeding habits. A clustering analysis of seven features of the proventriculus was constructed. It revealed that the proventriculus had significance for taxonomy and species relationships. Observations on morphological characterization of proventricular morphology will be useful in future studies of the feeding habits and phylogeny of crickets.

Video quality assessment based on data hiding driven by optical flow information

2003 ◽  
Author(s):  
Mylene C. Q. Farias ◽  
Marco Carli ◽  
Alessandro Neri ◽  
Sanjit K. Mitra
Keyword(s):  
Optical Flow ◽  
Quality Assessment ◽  
Data Hiding ◽  
Video Quality ◽  
Video Quality Assessment ◽  
Flow Information

scholarly journals Unmanned Aerial Vehicle Navigation Using Wide-Field Optical Flow and Inertial Sensors

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Matthew B. Rhudy ◽  
Yu Gu ◽  
Haiyang Chao ◽  
Jason N. Gross
Keyword(s):  
Optical Flow ◽  
Unmanned Aerial Vehicle ◽  
Inertial Sensors ◽  
Wide Field ◽  
Flight Data ◽  
Information Filter ◽  
Full State ◽  
Flow Information ◽  
Aerial Vehicle ◽  
Image Distance

This paper offers a set of novel navigation techniques that rely on the use of inertial sensors and wide-field optical flow information. The aircraft ground velocity and attitude states are estimated with an Unscented Information Filter (UIF) and are evaluated with respect to two sets of experimental flight data collected from an Unmanned Aerial Vehicle (UAV). Two different formulations are proposed, a full state formulation including velocity and attitude and a simplified formulation which assumes that the lateral and vertical velocity of the aircraft are negligible. An additional state is also considered within each formulation to recover the image distance which can be measured using a laser rangefinder. The results demonstrate that the full state formulation is able to estimate the aircraft ground velocity to within 1.3 m/s of a GPS receiver solution used as reference “truth” and regulate attitude angles within 1.4 degrees standard deviation of error for both sets of flight data.

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