Object recognition apparatus for vehicle and distance measurement apparatus

• US 7,761,236 B2
• Filed: 09/30/2008
• Issued: 07/20/2010
• Est. Priority Date: 12/05/2002
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Matsuoka, Keiji, Nozawa, Toyohito, Natsume, Tsutomu, Ohkata, Hiroshi, Hoashi, Yoshiaki, Samukawa, Yoshie, Teramura, Eiji
• Primary Examiner(s): To; Tuan C
• Application Number:
  US12/285,199
• Publication Number:
  US 20090045999A1
• Time in Patent Office: 658 Days
• Field of Search: 701/301, 701/96, 356/4.07, 356/4.01, 356/4.08, 340/435, 340/436, 340/902, 340/903, 342/42, 342/61, 342/47, 342/73, 342/108, 342/104, 342/147, 342/109, 342/107, 342/118, 396/106, 396/108
• US Class Current: 701/301
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60W 2554/00 Input parameters relating to objects
• CPC Class Codes: B60W 2554/802 Longitudinal distance
• CPC Class Codes: B60W 2554/804 Relative longitudinal speed
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/9319 Controlling the accelerator
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section

Abstract

In an object recognition apparatus for a vehicle which uses intensities of reflected waves from reflecting objects to make a recognition on whether a reflecting object is a vehicle or a non-vehicle, a plurality of transmission waves are emitted to receive a plurality of reflected waves from the reflecting objects, and a decision is made as to whether or not the reflecting object producing the plurality of reflected waves is a unitary reflecting object. If the decision shows a unitary reflecting object, the highest intensity of intensities of the reflected waves from the unitary reflecting object is compared with a reference intensity to makes a decision on whether the reflecting object is a vehicle or a non-vehicle. This enables univocally making a decision for each unitary reflecting object as to whether the reflecting object is more likely to be a vehicle or to be a non-vehicle, thus improving the recognition accuracy.

Claims

1. An object recognition apparatus for a vehicle comprising:

radar means for transmitting a plurality of transmission waves throughout a predetermined angular range in each of vertical and horizontal directions of said vehicle, receiving a plurality of waves from a plurality of reflecting objects in response to the transmission, and detecting distances to the reflecting objects, angles of the reflected waves in the vertical and horizontal directions, and intensities of the reflected waves by using the reflected waves that have been received;

decision means for i) determining that the plurality of reflecting objects causing the plurality of reflected waves satisfy a predetermined unity condition on the basis of the detected distances and ii) deciding that the plurality of reflecting objects constitute a unitary reflecting object when it is determined that the plurality of reflecting objects causing the plurality of reflected waves satisfy the predetermined unity condition;

selection means for selecting the highest intensity among the intensities of the reflected waves from the reflecting objects decided to be the unitary reflecting object by the decision means; and

recognition means for recognizing the reflecting objects on the basis of the distances and the angles and for enhancing a probability that the reflecting objects are recognized as a non-vehicle when the highest intensity selected by the selection means is lower than a predetermined reference intensity.

2. The apparatus according to claim 1, wherein the predetermined reference intensity for a long distance to the reflecting object is set at a lower value than the predetermined reference intensity for a short distance to the reflecting object.

3. The apparatus according to claim 1, further comprising shape calculation means for calculating a shape of the reflecting objects on the basis of the distances and the angles,

wherein the recognition means enhances the probability when the highest intensity is lower then the predetermined reference intensity and the calculated shape of the reflecting objects are different from a shape of a vehicle.

4. The apparatus according to claim 3, wherein, when a width of the calculated shape of the reflecting vehicles is shorter than a width of the shape of the vehicle, said recognition means is adapted to recognize that the shape of the reflecting object is different from the shape of the vehicle.

5. The apparatus according to claim 1, wherein the recognition means is adapted to use the highest intensity of the reflected waves to conduct the enhancing when the distances are shorter than a predetermined short distance.

6. A distance measurement apparatus comprising:

outputting means for emitting a transmission wave to around a vehicle to output a reception signal corresponding to an intensity of a reflected wave thereof;

decision means for making a decision as to whether or not an amplitude and a wavelength of the reception signal satisfy a predetermined relationship; and

detection means for detecting a distance to a reflecting object on the basis of the reception signal satisfying the predetermined relationship as a decision result in the decision means, wherein the decision means includes;

first amplitude decision means for making a decision as to whether or not the amplitude of the reception signal exceeds a predetermined first predetermined value;

second amplitude decision means for making a decision as to whether or not the amplitude of the reception signal exceeds a second predetermined value smaller than the first predetermined value; and

time width decision means for making a decision on the relationship in magnitude between a time width for which the amplitude of the reception signal exceeds the second predetermined value and a preset reference time width, wherein the time width decision means decides whether or not the magnitude of the amplitude of the reception signal decided by the first and second amplitude decision means and the length of the time width decided by the time width decision means satisfies the predetermined relationship.

7. The apparatus according to claim 6, wherein the reference time width is set at a time width for which the amplitude of the reception signal exceeds the second predetermined value in a case in which the amplitude of the reception signal exceeds the first predetermined value and the reception signal is in a normal condition.

8. The apparatus according to claim 6, wherein said decision means makes a decision that said predetermined relationship is not satisfied, when said first amplitude decision means makes a decision that the amplitude of said reception signal does not exceed said first predetermined value, said second amplitude decision means makes a decision that the amplitude of said reception signal exceeds said second predetermined value and said time width decision means makes a decision that the time width exceeds said reference time width.

9. The apparatus according to claim 6, wherein, in a case in which said first amplitude decision means makes a decision that the amplitude of said reception signal exceeds said first predetermined value and said time width decision means makes a decision that the time width does not reach said reference time width, said decision means replaces the time width with said reference time width and makes a decision indicative of the satisfaction of said predetermined relationship.

10. The apparatus according to claim 6, wherein said detection means includes:

a first intermediate time correction means for, when a decision result in said first amplitude decision means shows that the amplitude of said reception signal exceeds said first predetermined value, correcting an intermediate time of the time width for which the amplitude of said reception signal exceeds said first predetermined value so that said intermediate time agrees with a time at which the amplitude of said reception signal reaches a maximum value; and

a second intermediate time correction means for, when a decision result in said second amplitude decision means shows that the amplitude of said reception signal exceeds said second predetermined value and a decision result in said first amplitude decision means shows that the amplitude of said reception signal does not exceed said first predetermined value, correcting an intermediate time of the time width for which the amplitude of said reception signal exceeds said second predetermined value so that said intermediate time agrees with a time at which the amplitude of said reception signal reaches a maximum value, wherein the distance to said reflecting object is detected by obtaining a time difference between the time of the emission of said transmission wave and the corrected intermediate time.

11. The apparatus according to claim 10, further comprising correction quantity changing means for, when the distance to said reflecting object detected by said detection means is below a predetermined distance, changing correction quantities in said first intermediate time correction means and said second intermediate time correction means.