U.S. flag
      An official website of the United States government, Department of Justice.
        Here's how you know
      Here's how you know**Official websites use .gov**
            
            A **.gov** website belongs to an official government organization in the United States.
      **Secure .gov websites use HTTPS**
            
            A **lock** (
            A locked padlock
            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. Menu

      
        close

            
            
                                              About NIJ
        
                    
  
          About NIJ
      
    
          The NIJ Director
          How NIJ Is Organized
          Mission and Guiding Principles
          Research and Development Process
          Strategic Framework
          Assessments of NIJ
          Annual Reports & Reports to Congress
          Staff Directory
          Funding & Awards
        
                    
  
          Funding & Awards
      
    
          Current Funding
          Forthcoming Funding
          Expired Funding
          Awards: Listing of Funded Projects
          Guidance for Applicants and Awardees
          Fellowship & Student Programs
          Travel Scholarships
          NIJ Challenge Program
          Library & Multimedia
        
                    
  
          Library & Multimedia
      
    
          NIJ Journal
          Podcasts
          Publications Listing
          Multimedia Listing
          Rated Practices on CrimeSolutions
          Rated Programs on CrimeSolutions
          Software & Databases
          Datasets
          Patents
          Topics
        
                    
  
          Topics
      
    
          Article Listing
          Corrections
          Courts
          Crime Prevention
          Crimes
          Drugs and Crime
          Equipment and Technology
          Forensic Sciences
          Youth Justice
          Justice System Reform
          Law Enforcement
          Tribal Crime and Justice
          Victims of Crime
          Events
        
                    
  
          Events
      
    
          NIJ 2024 Research Conference
          Scheduled Events
          On-Demand Events
          Research Meetings & Workshops
          NIJ-Hosted Online Training

                            
                                About
          Contact Us
          Subscribe
          Topics A-Z
                  Share
FacebookXLinkedInRedditPinterestEmail Home
                            Library & Multimedia
 PDEs on Graphs for Semi-Supervised Learning Applied to First-Person Activity Recognition in Body-Worn Video
NCJ Number
              304522

Author(s)
          H. Li;
                        et al
Date Published

2021
Length
              24 pages
Annotation
              This paper showcases the use of PDE-based graph methods for modern machine learning applications.
Abstract
              We consider a case study of body-worn video classification because of the large volume of data and the lack of training data due to sensitivity of the information. Many modern artificial intelligence methods are turning to deep learning which typically requires a lot of training data to be effective. They can also suffer from issues of trust because the heavy use of training data can inadvertently provide information about details of the training images and could compromise privacy. Our alternate approach is a physics-based machine learning that uses classical ideas like optical flow for video analysis paired with linear mixture models such as non-negative matrix factorization along with PDE-based graph classification methods that parallel geometric equations from PDE such as motion by mean curvature. The upshot is a methodology that can work well on video with modest amounts of training data and that can also be used to compress the information about the video scene so that no personal information is contained in the compressed data, making it possible to provide a larger group of people access to these compressed data without compromising privacy. The compressed data retains information about the wearer of the camera while discarding information about people, objects, and places in the scene. (Publisher Abstract Approved)
      
  
          Additional Details
Grant Number(s)
        2014-R2-CX-0101


  
  
        
  Agencies
        NIJ-Sponsored


  
  
        
  Award
        Testing and Evaluating Body Worn Video Technology in the Los Angeles Police Department
    
  
  
Date Published: January 1, 2021
    
          Downloads
        
                      PDF

Side navigation
  

        

  
  
              NIJ Journal
    
      
            
            
            
      Podcasts
    
      
            
            
            
      Publications Listing
    
      
            
            
            
      Multimedia Listing
    
      
            
            
            
      Rated Practices on CrimeSolutions
    
      
            
            
            
      Rated Programs on CrimeSolutions
    
      
            
            
            
      Software & Databases
    
      
            
            
            
      Datasets
    
      
            
            
            
      PatentsRelated Topics
        
                Equipment and technology
        Body-worn cameras
        Video files
        Police training equipment
        Police training innovations



  
Similar Publications
        
                      Discouraging the Demand That Fosters Sex Trafficking: Collaboration through Augmented Intelligence
                  A two-stage Cox process model with spatial and nonspatial covariates
                  A case study for local data surveillance in opioid overdose fatalities in Cuyahoga County, OH 2016-2020
 Top

      National Institute of Justice

        
        
                        About NIJ
                    About NIJ
      
    
                  How NIJ Is Organized
      
    
                  NIJ Director
      
    
                  Research Disclaimer
      
    
                  Funding & Awards
                    Funding & Awards Home
      
    
                  Awards Listing
      
    
                  Current Funding
      
    
                  Guidance for Applicants and Awardees
      
    
                  Resources
                    Events
      
    
                  Podcasts
      
    
                  Publications
      
    
                  Topics
      
    
                  Multimedia
      
    
                  Reuse Policy
      
    
                  Contacts
                    Contact NIJ
      
    
                  Staff Directory
      
    
                  Submit a FOIA Request
      
    
                  File a Civil Rights ComplaintFacebook
          
                      X
          
                      YouTube
  

      810 7th St. NW, Washington, D.C. 20531
      
              Secondary Footer link menu
            Accessibility
              Plain Language
              Privacy Policy
              Legal Policies and Disclaimer
              No FEAR Act
              Freedom of Information Act
              USA.gov
              Justice.gov