DRIVE RECORDER

• US 20110254676A1
• Filed: 04/19/2011
• Published: 10/20/2011
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Marumoto, Kyoji
• Granted Patent: US 8,786,420 B2
• Time in Patent Office: Days
• US Class Current: 340/441
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C
• CPC Class Codes: G07C 5/085 using electronic data carriers

Abstract

A drive recorder of the invention includes a trigger judgment circuit that calculates, with respect to acceleration data of a vehicle, first and second moving averages as moving averages of two different time series, and that generates a trigger signal according to a result of comparing a differential value of the first and second moving averages or an absolute value of the differential value with a predetermined threshold value.

Claims

1. A drive recorder, comprising:

a trigger judgment circuit that calculates, with respect to acceleration data of a vehicle, first and second moving averages as moving averages of two different time series, and that generates a trigger signal according to a result of comparing a differential value or an absolute differential value of the first and second moving averages with a predetermined threshold value.

2. The drive recorder of claim 1,

wherein the first and second moving averages are values that are calculated with respect to acceleration data in two different time spans that are continuous and that may partly overlap by overlapping acceleration data.

3. The drive recorder of claim 2, wherein the trigger judgment circuit includes:

a register that stores the acceleration data therein;

an averaging processing portion that calculates the first and second moving averages based on the acceleration data stored in the register;

a subtraction processing portion that calculates a differential value or an absolute differential value of the first and second moving averages that are calculated by the averaging processing portion; and

a threshold-value comparison portion that compares the differential value or the absolute differential value of the first and second moving averages that is calculated by the subtraction processing portion with a predetermined threshold value to thereby generate the trigger signal.

4. The drive recorder of claim 1, further comprising:

a microcomputer that reads and executes a predetermined trigger judgment program to thereby function as the trigger judgment circuit.

5. The drive recorder of claim 2, wherein the overlapping acceleration data includes zero to several samples of acceleration data.

6. The drive recorder of claim 1, wherein lengths of the time spans for calculating the first and second moving averages are each arbitrarily set.

7. The drive recorder of claim 1, wherein lengths of time spans for calculating the first and second moving averages are each 0.3 to 0.5 seconds.

8. The drive recorder of claim 1, further comprising:

a control portion that decides, based on the trigger signal, whether or not to store driving condition data of a vehicle in a nonvolatile manner.

9. The drive recorder of claim 1, further comprising:

a control portion that decides, based on the trigger signal, whether or not to alert a driver.

10. The drive recorder of claim 1, further comprising:

a data collection portion that collects the driving condition data of a vehicle in a time series.

11. The drive recorder of claim 10, wherein the data collection portion includes:

an imaging portion that shoots surroundings of a vehicle and generates image data.

12. The drive recorder of claim 10, wherein the data collection portion includes a GPS receiving portion that uses a satellite signal from a GPS satellite to generate vehicle positional data.

13. The drive recorder of claim 10, wherein the data collection portion includes:

an acceleration sensor that detects acceleration in each of three axial directions which are orthogonal to one another.

14. The drive recorder of claim 10, wherein the data collection portion includes an interface portion that acquires operation condition data of each part of a vehicle inputted from an electric control unit mounted in a vehicle and various detection data inputted from an in-vehicle sensor.

15. The drive recorder of claim 10, wherein the data collection portion includes a real time clock that generates time data indicating date and time.

16. The drive recorder of claim 10, further comprising:

a storage portion that stores the driving condition data therein in a nonvolatile manner according to the trigger signal.

17. The drive recorder of claim 10, further comprising:

a warning portion that gives a warning to a driver according to the trigger signal.

18. A trigger judgment program that is read and executed by a microcomputer incorporated in a drive recorder,

the trigger judgment program making the microcomputer function as a trigger judgment circuit

that calculates, from acceleration data of a vehicle, first and second moving averages of two different time series, and

that generates a trigger signal according to a result of comparing a differential value or an absolute differential value of the first and second moving averages with a predetermined threshold value.

19. The trigger judgment program of claim 18,

wherein the trigger judgment program makes the microcomputer function as components of the trigger judgment circuit,

the components including:

a register that stores acceleration data therein;

an averaging processing portion that calculates the first and second moving averages based on the acceleration data stored in the register;

a subtraction processing portion that calculates a differential value or an absolute differential value of the first and second moving averages that are calculated by the averaging processing portion; and

a threshold-value comparison portion that compares the differential value or the absolute differential value of the first and second moving averages that is calculated by the subtraction processing portion with a predetermined threshold value to thereby generate the trigger signal.