Driving Assistance Device Using Dynamic Collision Time Calculation
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Solution Overview
Problem
Existing driving assistance systems using monocular imaging devices face challenges in accurately acquiring distance information, leading to potential noise and errors, which can result in unnecessary operations such as alarms and automatic braking, and fail to provide timely assistance when the collision possibility is low.
Innovation Solution
A driving assistance device that includes a distance information acquisition unit for obtaining relative distance, velocity, and acceleration from a monocular imaging device, a predicted collision time calculation unit that considers acceleration, a deceleration state determination unit, and a use determination unit to selectively use ETTC or TTC based on the deceleration state and collision possibility of the preceding vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If ETTC (Enhanced Time-To-Collision) is used as the predicted collision time by considering relative acceleration, then the driving assistance can be performed at an earlier timing, but the measurement precision deteriorates due to noise and errors in acceleration data acquired from a monocular imaging device
Solution Approach 1:
The system dynamically changes the parameter used for predicted collision time calculation based on the detection result. When deceleration is detected, ETTC (using acceleration) is selected; when no deceleration is detected, TTC (using only distance and velocity) is selected. This parameter switching resolves the contradiction by using the more accurate TTC when acceleration data is noisy, while enabling early warning with ETTC when deceleration is confirmed.
Solution Approach 2:
The system dynamically switches between different collision time calculation methods (TTC and ETTC) based on the real-time deceleration state of the preceding vehicle. This dynamic adaptation allows the system to optimize between early warning capability and measurement accuracy by selecting the appropriate calculation method for the current driving condition.
2Loss of time
If driving assistance is performed based on ETTC when the preceding vehicle is in deceleration state, then the collision warning can be provided earlier, but unnecessary operations occur when collision possibility is low
Solution Approach 1:
The system performs a preliminary check for collision possibility (using distance and velocity) before executing the driving assistance operation. This preliminary action filters out cases where the preceding vehicle is decelerating but no actual collision risk exists, thereby preventing unnecessary operations while maintaining early warning capability when real risk is present.
Solution Approach 2:
The system uses feedback from the collision possibility determination to control whether driving assistance is activated. The deceleration state and collision possibility results feed back to the use determination unit, which then decides whether to activate the safety device, ensuring that assistance is provided only when both deceleration and collision risk are present.
3Device complexity
If a monocular imaging device is used to acquire distance information, then the device complexity is reduced, but the measurement precision of distance, velocity, and acceleration deteriorates
Solution Approach 1:
The system changes the parameters used for collision time calculation based on the available data quality. When using a monocular imaging device with limited precision, the system switches between TTC (less sensitive to precision errors) and ETTC (more accurate but sensitive to noise) based on the detected deceleration state, thereby compensating for the inherent precision limitations of the simple imaging device.
Data Source
AI summary
In a driving assistance device, a distance information is acquired based on an image acquired by an imaging device mounted on a vehicle. The distance information includes a relative distance of a preceding vehicle in a travelling direction of the own vehicle, relative velocity thereof, and acceleration information thereof including relative acceleration. A time required until the own vehicle collides with the preceding vehicle is calculated with consideration of the acceleration information as a predicted collision time. It is determined whether or not the preceding vehicle is in a deceleration state by using the relative velocity. Further it is determined whether or not a collision possibility between the own vehicle and the preceding vehicle exists, and it is also determined to use the predicted collision time on the condition that the preceding vehicle is determined to be in the deceleration state and the collision possibility is determined to exist.