Motion detecting method and apparatus

• US 20070230785A1
• Filed: 03/21/2007
• Published: 10/04/2007
• Est. Priority Date: 03/22/2006
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Watanabe, Seigo
• Granted Patent: US 7,813,530 B2
• Time in Patent Office: Days
• US Class Current: 382/181
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments

Abstract

A motion detection apparatus. A characteristic region is extracted from an image produced by an imaging device. A modified region is formed by modifying the characteristic region. Voting occurs so as to count up to increase a count value at a memory address corresponding to a location inside the modified region and to reset a count value at a memory address corresponding to a location outside the modified region. At least one of the moving direction and the moving speed of the modified region is calculated based on a difference among accumulated count values for adjacent locations. The position of the modified region can be calculated based on count values and locations in the modified region.

Claims

1. A motion detection apparatus, comprising:

an imaging device; and

a control unit operable to;

extract a characteristic region from an image produced by the imaging device;

form a modified region by modifying the characteristic region;

count up to increase a first count value at a first memory address corresponding to a location inside the modified region;

reset a second count value at a second memory address corresponding to a location outside the modified region;

calculate a moving direction and a moving speed of the modified region based on a difference among accumulated count values for adjacent locations; and

calculate a position of the modified region based on count values and locations in the modified region.

2. The apparatus according to claim 1 wherein the control unit is further operable to extract the characteristic region from the image produced by the imaging device by extracting a region in which an image density is higher than a predetermined threshold.

3. The apparatus according to claim 2 wherein the predetermined threshold is lower than a noise level of noise superposed on the image produced by the imaging device.

4. The apparatus according to claim 1 wherein the control unit is further operable to modify the characteristic region by calculating a gravity center position of the characteristic region and forming the modified region spreading in a range of a plurality of pixels around the gravity center position as a center.

5. The apparatus according to claim 1 wherein the control unit is further operable to calculate the position of the modified region by dividing a summation of products, each of the products obtained by multiplying each location in the modified region by a corresponding count value, by a summation of the corresponding count values of the locations in the modified region.

6. The apparatus according to claim 1 wherein the control unit is further operable to modify the characteristic region by modifying the characteristic region based on a speed of an object whose speed is to be detected.

7. The apparatus according to claim 1 wherein the controller is further operable to:

receive images produced by the imaging device in a form of consecutive frames; and

wherein a frame rate of the consecutive frames is based on an assumed moving speed of an object to be detected on the images.

8. A motion detection apparatus, comprising:

imaging means for forming an image of a scene around a mounting location;

characteristic region extracting means for extracting a characteristic region in the image;

characteristic region modifying means for forming a modified region by modifying the characteristic region;

voting means for increasing a first count value in a first memory address corresponding to a location inside the modified region and for resetting a second count value at a second memory address corresponding to a location outside the modified region;

moving speed calculating means for calculating a moving direction and a moving speed of the modified region based on a difference among count values accumulated at adjacent memory addresses by the voting means; and

position calculating means for calculating a position of the modified region based on count values and locations in the modified region.

9. The apparatus according to claim 8 wherein the mounting location is a vehicle.

10. A motion detection method, comprising:

extracting a characteristic region from an input image;

modifying the characteristic region to form a modified region;

counting to increase or decrease a first count value at a first memory address corresponding to a location inside the modified region;

resetting a second count value at a second memory address corresponding to a location outside the modified region; and

calculating at least one of a moving direction and a moving speed of the modified region based on a difference of count values accumulated at memory addresses for two adjacent locations.

11. The method according to claim 10, further comprising:

calculating a position of the modified region based on locations in the modified region and respective count values at the memory addresses.

12. The method according to claim 11 wherein calculating the position of the modified region further comprises:

multiplying each location in the modified region by a corresponding count value to obtain a respective product;

summing each of the respective products together to obtain a summation of products;

summing the corresponding count values of the locations in the modified region to obtain a summation of count values; and

dividing the summation of products by the summation of count values to obtain the position.

13. The method according to claim 10 wherein extracting the characteristic region from the input image further comprises:

extracting a region in which an image density is higher than a predetermined threshold, the region defining the characteristic region.