On-vehicle Camera Glass Shield Refraction Error Correction
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Solution Overview
Problem
Existing on-vehicle camera systems face challenges in accurately measuring distances through glass shields without removing them or using additional distance measurement devices, as they introduce errors due to refraction and undulation.
Innovation Solution
An on-vehicle camera system with a pair of imaging elements and an error information storage unit that detects and corrects errors caused by glass shields by storing error information related to image-forming position differences between pixel positions, allowing for accurate distance measurement without removing the glass shield or using additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass shield is installed on the vehicle for safety and comfort, then the vehicle's safety and comfort are improved, but distance measurement errors occur due to refraction and undulation of the glass shield
Solution Approach 1:
The patent changes the parameter of the imaging system by introducing a plurality of imaging elements with different optical paths. By capturing images through multiple regions of the glass shield (including areas with different undulation characteristics), the system obtains multiple sets of parallax data that can be used to calculate and correct measurement errors caused by glass shield refraction and undulation.
Solution Approach 2:
The patent creates multiple copies of the imaging function using multiple imaging elements. Each imaging element captures a copy of the object image through a different path in the glass shield, allowing the system to compare and differentiate between parallax caused by stereo configuration and parallax caused by glass shield distortion, thereby enabling error correction.
2Measurement precision
If the glass shield is removed to eliminate measurement errors, then distance measurement accuracy is improved, but the vehicle's safety and comfort are reduced
Solution Approach 1:
Instead of removing the glass shield, the patent changes the measurement approach by using multiple imaging elements to capture images through different regions of the glass shield. This allows the system to maintain the glass shield while obtaining measurement data that can be corrected for glass-induced errors, thus preserving both safety/comfort and measurement accuracy.
Solution Approach 2:
The patent converts the harmful effect of the glass shield (which causes measurement errors) into a beneficial situation. By deliberately imaging through multiple regions of the glass shield including areas with known undulation characteristics, the system obtains additional information that enables it to calculate and correct the measurement errors, thus turning the glass shield from a source of error into a source of correction data.
3Measurement precision
If additional distance measurement devices are used to correct glass shield errors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the imaging system multi-functional by using the same imaging elements that capture object images to also capture calibration chart images. The imaging elements serve dual purposes: normal object detection and glass shield error characterization. This eliminates the need for separate calibration devices while maintaining measurement accuracy.
Solution Approach 2:
The system performs self-calibration by using its own imaging elements to capture images of a calibration chart through the glass shield. The calibration data is stored and automatically used to correct measurement errors during normal operation. This self-service approach eliminates the need for external calibration equipment or additional measurement devices.
4Measurement precision
If the glass shield is removed during calibration, then calibration accuracy is improved, but the calibration process becomes more complex and time-consuming
Solution Approach 1:
The patent performs calibration actions in advance by capturing images of a calibration chart through the glass shield using multiple imaging elements. The calibration data, including error information for each pixel position, is stored in advance and automatically applied during normal operation. This preliminary calibration eliminates the need for complex real-time calibration procedures.
Solution Approach 2:
The system performs self-calibration by using its own imaging elements to capture and process calibration chart images through the glass shield. The calibration process is automated, with the system automatically calculating error information and storing it for future use. This eliminates the need for manual calibration procedures or external calibration equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces distance measurement errors caused by glass shields by correcting image-forming position differences, enabling precise object recognition and measurement through the glass shield, enhancing safety and accuracy during vehicle operations.
Implementation Method 1
error caused by the glass shield, the error included in a difference in image-forming positions of the object between pixel positions of the pair of imaging elements
Data Source
Figure 1
Figure 2A~2B
Figure 2C~3
AI summary
The present invention provides an on-vehicle camera that is capable of reducing distance measurement error caused by a glass shield without using another distance measurement device and without requiring the glass shield to be removed, a method for adjusting the on-vehicle camera, and an on-vehicle camera system. The present invention pertains to an on-vehicle camera 10 that photographs an object outside a vehicle through a glass shield of the vehicle. The on-vehicle camera 10 is provided with: a pair of imaging elements; and an error information storage unit (storage unit 14). The error information storage unit stores, for each pixel position, error information about an error which is caused by the glass shield and included in a difference between object image-forming positions at the pixel positions of the imaging elements.