Passive velocity measuring device

• US 5,742,699 A
• Filed: 08/31/1995
• Issued: 04/21/1998
• Est. Priority Date: 08/31/1995
• Status: Expired due to Term

• Current Assignee: James H. Pierce, William A. Adkins
• Original Assignee: James H. Pierce, William A. Adkins
• Inventors: Pierce, James H., Adkins, William A.
• Primary Examiner(s): Couso, Yon
• Assistant Examiner(s): BOBYS, MARC P
• Application Number:
  US08/522,170
• Time in Patent Office: 964 Days
• Field of Search: 382/103-105, 382/107, 340/936, 340/937, 348/137, 348/140, 348/149, 364/423.098, 364/438
• US Class Current: 382/107
• CPC Class Codes: G01P 3/38 using photographic means
• CPC Class Codes: G01P 3/806 in devices of the type to be classified in G01P3/68

Abstract

The presented invention provides the velocity of a moving target from a remote location. A CCD camera receives the image of the target vehicle and records this information on CCD array. The camera then outputs this information in a standard video format such as RS-170, NTSC, or equivalent to the frame grabber circuit card assembly located in the main computer. Custom software along with commercial frame grabber imaging software operates the computer in a Windows or DOS environment. The system will correlate the image of multiple frames stored in the frame grabber circuit card, along with the overlain reference lines and determine the velocity of the target vehicle in miles or kilometers per hour. The image data will be stored in the computer on removable media, along with all pertinent data of the incident including the time/date/location stamp, along with calibration factors and an image of the vehicle operator.

Claims

1. An apparatus for passively measuring the velocity of a moving vehicle comprising:

a camera for acquiring images;

a computer for processing data;

said camera utilizing a frame transfer CCD for acquiring images, wherein said images include said moving vehicle approaching said apparatus and wherein light from said moving vehicle is passed through a near field lens, reflected by a fold mirror, reflected off a steering mirror, and finally passed to said frame transfer CCD for near field operation, and wherein light from said moving vehicle is passed through a far field lens and then passed directly to said frame transfer CCD for far field operation, and wherein said frame transfer CCD sends an image of said moving vehicle to said computer to be processed by a frame grabber which produces multiple frames each with an image of said moving vehicle to be sequentially displayed on a monitor;

said camera is initially calibrated for said far field operation in a laboratory environment using known size targets at known distances and mapping CCD pixels thus producing data which is input into a software lookup table for access by said computer and further producing multiple optical calibration factors dependent on zoom characteristics of said camera, said optical calibration factors placed on said camera so as to be accessible for manual input from said computer for field calibration of said apparatus;

said apparatus is initialized and during said initialization data regarding time, date, location, and speed limit for the site of speed measurement is input into said computer, also during said initialization, camera pointing and video contrast and brightness are set up, and wherein said camera pointing involves pointing said camera so that said CCD acquires images of a first stationary object at a known distance from said apparatus, and a second stationary object at a second distance which is closer to said apparatus than said distance of said first stationary object, said first and second stationary objects being positioned along said moving vehicle'"'"'s path, and wherein said first and second stationary objects are displayed on said monitor and wherein said monitor displays parallel lines perpendicular to vehicle motion, a first parallel line to be associated with said first stationary object and a second parallel line to be associated with said second stationary object,

following said initialization, said moving vehicle is tracked using a centroid tracking algorithm associated with said frame grabber, and an initial determination is made that said moving vehicle is speeding when it is determined that said moving vehicle'"'"'s speed is greater than said speed limit and where in said moving vehicle'"'"'s speed is determined by examining two frames with a two second time interval between them, calculating the difference in said vehicle'"'"'s height between said two frames, using said optical calibration factors to calculate a distance traveled by said vehicle towards said apparatus during said two second time interval, and dividing said distance by said two second time interval;

after said initial determination is made that said moving vehicle is speeding a second determination of said moving vehicle'"'"'s speed is made and compared to said speed limit, wherein said moving vehicle'"'"'s speed is determined by said computer prompting said operator to use a pointing device to drag said first parallel line so that it is adjacent to said first stationary object and to drag said second parallel line so that it is adjacent to said second stationary object, then said computer adds nine more lines equidistant and parallel between said first and second parallel lines so as to generate a grid with known distances between grid lines to be displayed on said display, wherein said moving vehicle is tracked using a centroid tracking algorithm associated with said frame grabber as it crosses said grid, distance and time measurements are made as said moving vehicle crosses each of said grid lines and calculations of velocity are made for ten samples and an average of said ten samples is calculated;

after said second determination of said moving vehicle'"'"'s speed is made, said apparatus switches to said near field operation to acquire a close up image of said moving vehicle and pertinent vehicle identification and said apparatus stores data of said moving vehicle when it is determined it has violated said speed limit, said data including time, date, location, calibration, and speeding information all superimposed on video including said close up image of said moving vehicle showing tag number and operator image.

2. A method for passively measuring the velocity of a moving vehicle comprising:

acquiring images using a camera utilizing a frame transfer CCD for acquiring images, wherein said images include said moving vehicle approaching said apparatus and wherein light from said moving vehicle is passed through a near field lens, reflected by a fold mirror, reflected off a steering mirror, and finally passed to said frame transfer CCD for near field operation, and wherein light from said moving vehicle is passed through a far field lens and then passed directly to said frame transfer CCD for far field operation, and wherein said frame transfer CCD sends an image of said moving vehicle to said computer to be processed by a frame grabber which produces multiple frames each with an image of said moving vehicle to be sequentially displayed on a monitor;

initially calibrating said camera for said far field operation in a laboratory environment using known size targets at known distances and mapping CCD pixels thus producing data which is input into a software lookup table for access by said computer and further producing multiple optical calibration factors dependent on zoom characteristics of said camera, said optical calibration factors placed on said camera so as to be accessible for manual input from said computer for field calibration of said apparatus;

initializing said apparatus and during said initialization data regarding time, date, location, and speed limit for the site of speed measurement is input into said computer, also during said initialization, camera pointing and video contrast and brightness are set up, and wherein said camera pointing involves pointing said camera so that said CCD acquires images of a first stationary object at a known distance from said apparatus, and a second stationary object at a second distance which is closer to said apparatus than said distance of said first stationary object, said first and second stationary objects being positioned along said moving vehicle'"'"'s path, and wherein said first and second stationary objects are displayed on said monitor and wherein said monitor displays parallel lines perpendicular to said moving vehicle'"'"'s motion, a first parallel line to be associated with said first stationary object and a second parallel line to be associated with said second stationary object;

following said initialization, said moving vehicle is tracked using a centroid tracking algorithm associated with said frame grabber, and an initial determination is made that said moving vehicle is speeding when it is determined that said moving vehicle'"'"'s speed is greater than said speed limit and wherein said moving vehicle'"'"'s speed is determined by examining two frames with a two second time interval between them, calculating the difference in said vehicle'"'"'s height between said two frames, using said optical calibration factors to calculate a distance traveled by said vehicle towards said apparatus during said two second time interval, and dividing said distance by said two second time interval;

after said initial determination is made that said moving vehicle is speeding a second determination of said moving vehicle'"'"'s speed is made and compared to said speed limit, wherein said moving vehicle'"'"'s speed is determined by said computer prompting said operator to use a pointing device to drag said first parallel line so that it is adjacent to said first stationary object and to drag said second parallel line so that it is adjacent to said second stationary object, then said computer adds nine more lines equidistant and parallel between said first and second parallel lines so as to generate a grid with known distances between grid lines to be displayed on said display, wherein said moving vehicle is tracked using a centroid tracking algorithm associated with said frame grabber as it crosses said grid, distance and time measurements are made as said moving vehicle crosses each of said grid lines and calculations of velocity are made for ten samples and an average of said ten samples is calculated;

after said second determination of said moving vehicle'"'"'s speed is made, said apparatus switches to said near field operation to acquire a close up image of said moving vehicle and pertinent vehicle identification and said apparatus stores data of said moving vehicle when it is determined it has violated said speed limit, said data including time, date, location, calibration, and speeding information all superimposed on video including said close up image of said moving vehicle showing tag number and operator image.