Detection apparatus for road obstructions

• US 20020005898A1
• Filed: 06/05/2001
• Published: 01/17/2002
• Est. Priority Date: 06/14/2000
• Status: Active Grant

• Current Assignee: KDDI Corporation
• Original Assignee: KDDI Corporation
• Inventors: Matsumoto, Shuichi, Wada, Masahiro, Kawada, Ryoichi
• Granted Patent: US 6,952,449 B2
• Time in Patent Office: Days
• US Class Current: 348/149
• CPC Class Codes: G06T 2207/30261 Obstacle
• CPC Class Codes: G06T 7/215 Motion-based segmentation
• CPC Class Codes: G06V 10/25 Determination of region of interest [ROI] or a volume of interest [VOI]
• CPC Class Codes: G06V 10/50 by performing operations within image blocks; by using histograms, e.g. histogram of oriented gradients [HoG]; by summing image-intensity values; Projection analysis
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors
• CPC Class Codes: H04N 7/188 Capturing isolated or intermittent images triggered by the occurrence of a predetermined event, e.g. an object reaching a predetermined position signal generation from motion picture films H04N5/253

Abstract

Road area blocks of monitoring camera video data are extracted by a road area block extractor, and motion vectors are calculated by a motion vector calculator. A motion vector direction detector detects the directions of the motion vectors. In a normal state, the mean value Θ and the variance σ_e² of the directions θ of the motion vectors are calculated and accumulated in a statistics memory. In detection of road obstructions, the directions of the motion vectors detected by the motion vector direction detector are transmitted to an abnormal motion vector degree Q calculator. An abnormal motion vector degree Q is calculated on the basis of the statistics accumulated in the statistics accumulated in the statistics memory. A comparator compares the abnormal motion vector degree Q with a threshold. When the abnormal motion vector degree Q is equal to or larger than the threshold, road obstructions are decided. Therefore, according to the present invention, a detection apparatus for road obstructions which is not easily affected by changes in brightness and color in an image and which is not easily adversely affected by the color of a running vehicle is provided.

Claims

1. A detection apparatus for road obstructions for automatically monitoring obstructions on a road by using a remote monitoring camera, comprising:

a motion vector calculator for calculating a motion vector of a video image in a road area;

a motion vector direction detector for detecting the direction of the motion vector; and

comparison means for comparing the direction of the motion vector with the average of the directions of pre-detected motion vectors in the road area in a normal state, and

wherein, when it is determined by the comparison means that the direction of the motion vector is offset from the average of the motion vectors in the road area in the normal state by not less than a predetermined value, road obstructions are decided.

3. A detection apparatus for road obstructions according to claim 1,

wherein the motion vector calculator calculates motion vectors of respective blocks of a video image in a road area, and the motion vector direction detector detects the directions of the motion vectors of the respective blocks.

2. A detection apparatus for road obstructions for automatically monitoring obstructions on a road by using a remote monitoring camera, comprising:

a motion vector calculator for calculating a motion vector of a video image in a road area;

a motion vector direction detector for detecting the direction of the motion vector;

a statistics memory for accumulating the direction of the motion vector and at least the mean value and the pre-detected variance of the directions of pre-detected motion vectors in a road area in a normal state; and

an abnormal motion vector degree calculator for calculating an abnormal motion vector degree from the direction of the motion vector detected by the motion vector direction detector and at least the mean value and the variance of the directions of the motion vectors in the road area in the normal state which are accumulated in the statistics memory, and

wherein road obstructions are detected on the basis of the abnormal motion vector degree calculated by the abnormal motion vector degree calculator.

4. A detection apparatus for road obstructions according to claim 2,

wherein the motion vector calculator calculates motion vectors of respective blocks of a video image in a road area, and the motion vector direction detector detects the directions of the motion vectors of the respective blocks.

5. A detection apparatus for road obstructions according to claim 2,

wherein the abnormal motion vector degree calculator calculates an abnormal motion vector degree Q of a motion vector θ

0 by the following expression when the mean value and the variance of the directions of the motion vectors in the road area in the normal state are represented by Θ and

σ

_e² respectively.

Q 1−

exp(−

(θ

0−

Θ

)²/2σ

_e²⁾