Parking assistance system

• US 6,999,003 B2
• Filed: 06/07/2005
• Issued: 02/14/2006
• Est. Priority Date: 06/23/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kato, Koji, Matsukawa, Norifumi, Sato, Yoshihisa
• Primary Examiner(s): Pope, Daryl C.
• Application Number:
  US11/146,107
• Publication Number:
  US 20050285758A1
• Time in Patent Office: 252 Days
• Field of Search: 340/932.2, 340/933, 340/438, 340/435, 340/436, 340/437, 340/903, 340/937
• US Class Current: 340/932.2
• CPC Class Codes: B60T 2201/10 Automatic or semi-automatic parking aid systems
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B62D 15/0285 Parking performed automatically
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2015/935 for measuring the contour, e.g. a trajectory of measurement points, representing the boundary of the parking space
• CPC Class Codes: G01S 2015/936 for measuring parking spaces extending transverse or diagonal to the driving direction, i.e. not parallel to the driving direction
• CPC Class Codes: G06V 10/25 Determination of region of interest [ROI] or a volume of interest [VOI]
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: G06V 20/586 of parking space
• CPC Class Codes: G08G 1/165 for passive traffic, e.g. including static obstacles, trees
• CPC Class Codes: G08G 1/168 Driving aids for parking, e.g. acoustic or visual feedback on parking space

Abstract

During a period until a subject vehicle stops to go back for being parked, detection distance data items and advance distance data items are obtained by using an ultrasonic sensor and a speed sensor. These data items are stored with both the data items mutually associated. The detection distance data item indicates a distance to a parked vehicle adjacent to the subject vehicle and the advance distance data item indicates a distance in which the subject vehicle advances. When computing a size of the parked vehicle from the advance distance data items, the size of the parked vehicle is determined to be shorter than an aggregated distance corresponding to the advance distance data items. This enables the determined size of the parked vehicle to approximate an actual size of the parked vehicle.

Claims

1. A parking assistance system provided in a subject vehicle, the system comprising:

a first distance measuring unit that measures a distance from a side of the subject vehicle to a parked vehicle based on a time period from when transmitting a signal that is transmitted from the side with directionality to when receiving a reflected signal;

a second distance measuring unit that measures an advance distance in an advance direction of the subject vehicle;

a storing unit that associates parked-vehicle distance data with advance distance data to store the parked-vehicle distance data and the advance distance data, wherein the parked-vehicle distance data indicates distances that are repeatedly measured by the first distance measuring unit while the advance distance data indicates advance distances measured by the second distance measuring unit;

a size determining unit that determines a size of the parked vehicle in the advance direction of the subject vehicle so that the size is shorter than a distance corresponding to the advance distance data;

a setting unit that sets a target parking region adjacent to the parked vehicle based on the size, wherein the subject vehicle is expected to be parked in the target parking region; and

an operation assisting unit that computes a positional relationship between the subject vehicle and the parked vehicle based on the parked-vehicle distance data and the advance distance data and then conducts an operation assistance for parking the subject vehicle in the target parking region.

2. The parking assistance system of claim 1,

wherein the size determining unit

classifies a distance corresponding to the advance distance data into a plurality of distance ranges and

determines a predetermined size pertinent to each of the distance ranges as the size of the parked vehicle.

3. The parking assistance system of claim 1,

wherein the size determining unit

determines a center position of the parked vehicle in the advance direction based on the parked-vehicle distance data and the advance distance data that is associated with the parked-vehicle distance data and

then determines a position of the parked vehicle to allow the size determined, based on the center position.

4. The parking assistance system of claim 3,

wherein the size determining unit

computes line segment data indicating an outline of the parked vehicle based on the parked-vehicle distance data and the advance distance data,

compares the line segment data with an inverse line segment data that is inverse to the line segment data while changing an overlapping range to thereby obtain a given overlapping range corresponding to a minimum total difference between the line segment data and the inverse line segment data, and

determines a center position of the parked vehicle from a center position of the given overlapping range.

5. The parking assistance system of claim 4,

wherein, when the size determining unit compares the line segment data with the inverse line segment data, an outline of an end of the parked vehicle is excluded from being indicated by the line segment data.

6. The parking assistance system of claim 3,

wherein the size determining unit

obtains a given position where a minimum distance from the subject vehicle to the parked vehicle is obtained using the advance distance data and

determines a center position of the parked vehicle based on the given position obtained.

7. The parking assistance system of claim 3,

wherein, in a case that the setting unit sets the target parking region in a range sandwiched between two parked vehicles, the size determining unit

determines a center position and a size of each of the two parked vehicles and

sets the target parking region when a parked space is more than a size of the subject vehicle, wherein the parked space is obtained by subtracting individual half sizes of the two parked vehicles from a distance between the center positions of the two parked vehicles.

8. The parking assistance system of claim 7,

wherein, only when the parked space is more than a sum of the size of the subject vehicle and a margin that is further considered for parking, the setting unit sets the target parking region.

9. The parking assistance system of claim 1,

wherein, when the subject vehicle stops and a transmission of the subject vehicle is switched to a shift position for going back, the setting unit sets the target parking region adjacent to either side of the parked vehicle based on a relative position to the parked vehicle and on whether an obstruction is present in a region adjacent to the parked vehicle.