The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform

Keiji Araki - One of the best experts on this subject based on the ideXlab platform.

  • method of processing Closed Circuit Television digital images for poor visibility identification
    Transportation Research Record, 2006
    Co-Authors: Toru Hagiwara, Yuji Ota, Yasuhiro Kaneda, Yasuhiro Nagata, Keiji Araki
    Abstract:

    This study proposes a method for identifying poor visibility under adverse weather conditions by processing Closed-Circuit Television (CCTV) digital images. The weighted intensity of the power spectrum (WIPS) was examined to determine its applicability as a value for the identification of poor visibility. The magnitude of WIPS represents the difference in spatial frequencies within the image on the basis of the human contrast sensitivity function. WIPS was calculated by the following image-processing procedure: the spatial frequency of the cutout image was calculated with a two-dimensional Fourier transform, and the power spectrum of the cutout image was calculated; WIPS was totaled at spatial frequencies that ranged from 1.5 to 18 cycles per degree. Two kinds of experiments were performed to determine whether WIPS represented the subjective visibility assessment values (SVAVs) given by the test subjects. Clear linear relationships between WIPS and SVAVs were found in both experiments. In addition, the tw...

  • simple way to use Closed Circuit Television road images for poor visibility information
    Transportation Research Record, 2006
    Co-Authors: Yasuhiro Nagata, Toru Hagiwara, Yasuhiro Kaneda, Keiji Araki, Keisuke Murakami
    Abstract:

    Road visibility information is important for driving safety, and the need for such information in winter is particularly great. Road administrators provide drivers with road images gathered using Closed-Circuit Television (CCTV) cameras installed along national highways. However, when road condition information is given as an image, the provision media are limited. Japan's Hokkaido Regional Development Bureau has sought ways to quantify road image information. If it can be proved that the estimation of road visibility from the same image does not differ among people and if drivers' assessments of visibility correlate with assessments given by a road image-based visibility scale (VS), then the VS can be used to quantify road visibility. VS is calculated from a weighted intensity of power spectrum developed by Hagiwara and colleagues. Subjective assessments of road images taken by CCTV cameras were surveyed. Assessments of daytime images also had little variation among subjects and correlated closely with t...

David Hillier - One of the best experts on this subject based on the ideXlab platform.

  • Commentary Closed‐Circuit Television in town centres
    International Journal of Retail & Distribution Management, 1997
    Co-Authors: Peter M. Jones, David Turner, David Hillier
    Abstract:

    Closed‐Circuit Television (CCTV) surveillance systems are becoming an increasingly popular weapon in the battle against crime in town and city centres. Provides a commentary on the employment of CCTV and suggests that they are most effective as part of an integrated and coherent town centre management strategy.

Kent Matthews - One of the best experts on this subject based on the ideXlab platform.

  • effect of urban Closed Circuit Television on assault injury and violence detection
    Injury Prevention, 2003
    Co-Authors: Vaseekaran Sivarajasingam, Jonathan Shepherd, Kent Matthews
    Abstract:

    Objective: To evaluate the effect of Closed Circuit Television (CCTV) surveillance on levels of assault injury and violence detection. Design: Intervention versus control study design. Setting: Five town/cities with CCTV surveillance and five, matched control centres without CCTV surveillance in England. Intervention: CCTV installation and surveillance. Methods: Assault related emergency department attendances and violent offences recorded by the police in CCTV and control centres in the four years, 1995–99, two years before and two years after CCTV installation, were compared. Results: Assault related emergency department attendances decreased in intervention centres (3% decrease, ratio 0.96; 95% confidence interval (CI) 0.93 to 0.99) and increased in control centres (11% increase, ratio 1.11; 95% CI 1.08 to 1.14). Overall, changes in emergency department assault attendance in CCTV and control centres were significantly different (t test, p 0.05). In CCTV centres, decreases in assault related emergency department attendances and increases in police violence detection were not uniform. Conclusion: CCTV surveillance was associated with increased police detection of violence and reductions in injury or severity of injury. CCTV centre variation deserves further study.

Toru Hagiwara - One of the best experts on this subject based on the ideXlab platform.

  • method of processing Closed Circuit Television digital images for poor visibility identification
    Transportation Research Record, 2006
    Co-Authors: Toru Hagiwara, Yuji Ota, Yasuhiro Kaneda, Yasuhiro Nagata, Keiji Araki
    Abstract:

    This study proposes a method for identifying poor visibility under adverse weather conditions by processing Closed-Circuit Television (CCTV) digital images. The weighted intensity of the power spectrum (WIPS) was examined to determine its applicability as a value for the identification of poor visibility. The magnitude of WIPS represents the difference in spatial frequencies within the image on the basis of the human contrast sensitivity function. WIPS was calculated by the following image-processing procedure: the spatial frequency of the cutout image was calculated with a two-dimensional Fourier transform, and the power spectrum of the cutout image was calculated; WIPS was totaled at spatial frequencies that ranged from 1.5 to 18 cycles per degree. Two kinds of experiments were performed to determine whether WIPS represented the subjective visibility assessment values (SVAVs) given by the test subjects. Clear linear relationships between WIPS and SVAVs were found in both experiments. In addition, the tw...

  • simple way to use Closed Circuit Television road images for poor visibility information
    Transportation Research Record, 2006
    Co-Authors: Yasuhiro Nagata, Toru Hagiwara, Yasuhiro Kaneda, Keiji Araki, Keisuke Murakami
    Abstract:

    Road visibility information is important for driving safety, and the need for such information in winter is particularly great. Road administrators provide drivers with road images gathered using Closed-Circuit Television (CCTV) cameras installed along national highways. However, when road condition information is given as an image, the provision media are limited. Japan's Hokkaido Regional Development Bureau has sought ways to quantify road image information. If it can be proved that the estimation of road visibility from the same image does not differ among people and if drivers' assessments of visibility correlate with assessments given by a road image-based visibility scale (VS), then the VS can be used to quantify road visibility. VS is calculated from a weighted intensity of power spectrum developed by Hagiwara and colleagues. Subjective assessments of road images taken by CCTV cameras were surveyed. Assessments of daytime images also had little variation among subjects and correlated closely with t...

Vaseekaran Sivarajasingam - One of the best experts on this subject based on the ideXlab platform.

  • effect of urban Closed Circuit Television on assault injury and violence detection
    Injury Prevention, 2003
    Co-Authors: Vaseekaran Sivarajasingam, Jonathan Shepherd, Kent Matthews
    Abstract:

    Objective: To evaluate the effect of Closed Circuit Television (CCTV) surveillance on levels of assault injury and violence detection. Design: Intervention versus control study design. Setting: Five town/cities with CCTV surveillance and five, matched control centres without CCTV surveillance in England. Intervention: CCTV installation and surveillance. Methods: Assault related emergency department attendances and violent offences recorded by the police in CCTV and control centres in the four years, 1995–99, two years before and two years after CCTV installation, were compared. Results: Assault related emergency department attendances decreased in intervention centres (3% decrease, ratio 0.96; 95% confidence interval (CI) 0.93 to 0.99) and increased in control centres (11% increase, ratio 1.11; 95% CI 1.08 to 1.14). Overall, changes in emergency department assault attendance in CCTV and control centres were significantly different (t test, p 0.05). In CCTV centres, decreases in assault related emergency department attendances and increases in police violence detection were not uniform. Conclusion: CCTV surveillance was associated with increased police detection of violence and reductions in injury or severity of injury. CCTV centre variation deserves further study.

  • Effect of Closed Circuit Television on urban violence.
    Journal of accident & emergency medicine, 1999
    Co-Authors: Vaseekaran Sivarajasingam, Jonathan Shepherd
    Abstract:

    OBJECTIVE: To evaluate the effect of city and town centre Closed Circuit Television (CCTV) surveillance on violence in terms of accident and emergency (A&E) department and police assault data. METHODS: A&E department and local police assault data in three centres in Wales (Cardiff, Swansea, and Rhyl) two years before and two years after the installation of CCTV were studied. British Crime Survey and police crime statistics were used as control data. RESULTS: A&E records of 24,442 assault patients and 3228 violent offences recorded by the police were studied. Data from two A&E departments (Swansea (+3%) and Rhyl (+45%)) showed increases in recorded assaults after CCTV installation but a decrease (12%) in the largest centre, Cardiff. There was an overall reduction in town/city centre violence from the A&E department perspective of 1% in the two years after CCTV installation. In contrast, police data demonstrated changes in the opposite direction (-44%, -24%, and +20% respectively) contributing to an overall decrease of 9%. British Crime Survey and police statistics for England and Wales demonstrated no overall change and a 16% increase respectively. CONCLUSIONS: City centre CCTV installation had no obvious influence on levels of assaults recorded in A&E departments. There was a negative relationship between police and A&E recording in all three centres. A&E departments are important and unique sources of information about community violence.