Moving object detection method and apparatus

• US 6,538,579 B1
• Filed: 01/30/1997
• Issued: 03/25/2003
• Est. Priority Date: 02/08/1996
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sunahara, Shuichi, Yoshikawa, Kazutoshi
• Primary Examiner(s): Wu, Daniel J.
• Application Number:
  US08/790,787
• Time in Patent Office: 2,245 Days
• Field of Search: 340/928, 340/933, 340/939, 340/937, 340/941, 348/148, 348/149, 701/117, 235/375, 235/384
• US Class Current: 340/928
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/1473 Recognising objects as potential recognition candidates based on visual cues, e.g. shapes
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

A moving object detection method and apparatus is proposed in which a plurality of heads are installed above a detection line traversing a road, their outputs undergo A/D conversion and binary conversion, and the outputs are then linked along the detection line. A vehicle detection preprocessor performs, on the obtained linked 0/1 existence data, vehicle detection preprocesses of filling-up, noise rejection, width maintaining, Y character profile prevention, delaying, maximum width checking, and so forth, in a predetermined sequence. A vehicle detection processor separates and detects entering vehicles, existing vehicles, corrected/deleted vehicles, and so forth, from the linked 0/1 existence data after vehicle detection preprocessing. False detection of moving objects is reduced.

Claims

1. A moving object detection method including:

a step for detecting existence of a moving object at a plurality of positions on a predetermined line by (i) arranging a plurality of distance sensors facing a single direction for scanning said predetermined line in said direction, (ii) scanning said predetermined line in said direction, each sensor producing an output signal indicative of the distance to said moving object in said direction, (iii) binarizing said output signals to produce 0/1 data bits, and (iv) linking said 0/1 data bits according to an order of arrangement of said sensors for producing a bit string, whereby said bit string is representative of existence and position of said moving object along said predetermined line;

a step for filtering the bit string with filtering characteristics determined according to an essential profile of the moving object and/or the bit string obtained in a previous period; and

a step to periodically execute said detecting and filtering steps.

2. A moving object detection apparatus comprising:

a plurality of distance sensors arranged to face a single direction for periodically scanning a plurality of positions on a predetermined line in said single direction, each sensor producing an output signal thereby;

means for binarizing said output signals according to an order of arrangement of said sensors to produce 0/1 data bits indicative of existence of said moving object at each sensor position;

means for linking said 0/1 data bits at each sensor position to produce a bit string representative of existence and position of said moving object along said predetermined line; and

filtering means for filtering the bit string obtained from the sensor in a certain period with filtering characteristics determined according to an essential profile of the moving object and/or the bit string obtained from the sensor in a previous period.

3. A moving object detection apparatus comprising:

a sensor for periodically detecting existence of the moving object at a plurality of positions on a predetermined line by scanning said predetermined line;

filtering means for filtering the moving object existence information obtained from the sensor in a certain period with filtering characteristics determined according to at least one of an essential profile of the moving object and the moving object existence information obtained from the sensor in a previous period; and

wherein said filtering characteristics include a width maintaining characteristic for correcting, when a plurality of mutually adjacent third positions for which moving object existence information has been obtained indicating moving object exists in a previous period and a plurality of mutually adjacent first positions for which moving object existence information has been obtained indicating moving object exists in a recent period at least partially overlap, the contents of moving object existence information at positions included in third positions and not included in the first positions to indicate moving object exists.

4. A moving object detection method comprising the steps of:

(a) searching a number of locations along a predetermined line;

(b) generating an image signal for each location indicative of presence of a moving object along the line;

(c) compensating the image signal;

(d) linking image signals compensated in step (c) from each location to determine the presence of the moving object;

(e) filtering the signals linked in step (d) with characteristics determined according to an essential profile of the moving object;

(f) comparing the signals filtered in step (e) with filtered signals from previous searches to produce an output;

(g) storing information derived from the output; and

(h) periodically executing steps (a) through (g).

5. A moving object detection apparatus comprising:

sensors for (i) searching a number of locations along a predetermined line and (ii) generating an image signal for each location indicative of presence of a moving object along the line;

a compensating device for compensating the image signal and producing a compensated signal thereby;

a generator for linking the compensated image signals from each location and at producing linked signals thereby;

filters for filtering the linked signals with characteristics determined according to an essential profile of the moving object and producing filtered signals thereby;

a comparing device for comparing the filtered signals with filtered signals from previous searches to produce an output; and

a memory for storing information derived from the output.