Other

Pulnix America, Inc.

Jai Pulnix, Inc.

Alves, James

James Alves

A license plate recognition process is described that includes automated image analysis integrated with human review and a definition of a plate grammar of license plate visual elements that are required to prepare a database search index that enables selection of a particular license plate, from a known population of all possible license plates issued for each and every jurisdiction of interest. The plate grammar includes visual elements that may be searched by both automated image analysis and by a human reviewer. The process includes creation of a question that guides a human reviewer into providing required information regarding a selected plate grammar element that is not identified by computerized image analysis. Integration of a manual review process within an automated process as opposed to manual review solely at a failed completion of the automated process is included. Methods are presented for creation of queries for manual review that take into account the skill and availability of the manual reviewer as well as optimizing for a shortest path to completion of the recognition of the license plate through the database search index.

License plate recognition

A digital camera control system that requires no light sensors is described. The control system relies on modeled external environmental geophysical solar parameters, geometric relationships between the object to be imaged and surrounding potentially shadowing objects, the material properties of the object to be imaged such as reflectivity are combined to produce the estimated irradiance on a camera sensor for the particular time of day, date and geometric relationship between the object and the sun. The calculated irradiance on the image sensor for the background of the object of interest and a feature to be recognized provide a contrast. The signal to noise requirements for the feature recognition are used to determine a minimum required contrast transfer function for the sensor. Control parameters for the sensor are then determined to meet the minimum contrast requirements. The system therefore provides a method to rapidly determine an optimum camera settings for any time of day and ensures the camera is always ready to capture at least the minimum required contrast image of a fast moving transient object. The system is demonstrated for use in a license plate imaging application.

Digital camera control system

A license plate recognition and image review system and processes are described. The system includes grouping of images that are determined to be of the same vehicle, using an image encoded database such that verification of a license plate read is done through comparison of images of the actual vehicle to images from the encoded database and testing of the accuracy of a manual review process by interspersing previously identified images with real images being reviewed in a batch process.

An HOV enforcement system comprises roadside imaging units connected over a network to a central processing center. The roadside imaging units include Ethernet cameras with integrated vehicle detectors, night-time lighting, and image servers. The central processing center includes a central server with license plate reading and vehicle matching software, storage and databases, and review staff to issue bills and citations.

High occupancy vehicle (HOV) lane enforcement

In a vehicle time-of-entry and time-of-exit system, the passing of a vehicle through an entrance generates a &ldquo;trigger-t &rdquo; signal. An entrance video camera provides realtime images of entering vehicles. The trigger-t signal causes one video frame of the image of vehicle to be stored or &ldquo;frame-grabbed&rdquo; in an entrance subsystem. A time-of-entry clock-time signal is used to time-stamp the image which is then forwarded on a connection to a matcher. The passing of a vehicle through an exit generates a &ldquo;trigger-t &rdquo; signal. An exit video camera provides realtime images of exiting vehicles. The trigger-t signal causes one video frame of the image of vehicle to be stored or &ldquo;frame-grabbed&rdquo; in an exit subsystem. A clock-time signal is used to time-stamp the image which is then forwarded on a connection to the matcher. A output automatically provides a length-of-stay for each exiting vehicle according to its time-of-entry. The matcher uses the unique characteristics in the images of the vehicles to declare a match. While a license plate number is unique, reading any or all of a license plate is not necessary for the extraction of visual signatures related to particular cars. For example, in the limited variety of cars that would patronize a particular parking lot, the color, trim, style, tires, wheelcovers, collision damage, etc., of each vehicle can be used in combination to distinguish individual ones.

System for recognizing the same vehicle at different times and places

A vehicle video imaging system comprises a white-light LED array for illuminating retro-reflective painted parts of a vehicle's license plate, a powerful flash with a visual spectrum cutout filter and a polarizing filter for illuminating any non-retro-reflective license plate paint and the vehicle itself. A video camera with a polarizing filter turned 90&deg; relative to the one in front of the flash receives the illuminated image of the vehicle and its license plate. The retro-reflective paint of a license plate will return polarized light as it is received, so the white-light LED array will provide all the illumination needed by the camera to get a good high-contrast picture of the license plate. The polarizing filters will combine to block out most of the light from the flash that was returned still-polarized by the retro-reflective-paint license plate. All other surfaces that do not have retro-reflective paint will bounce-back and scatter the light from both the polarized flash and non-polarized light.

Growing community of inventors

San Diego, CA, United States of America

James Alves