Monitor Device Day Night Determination Using Reference Subjects
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Solution Overview
Problem
Conventional monitor devices mounted on vehicles face challenges in accurately determining day or night conditions due to varying luminance levels caused by changes in weather, terrain, and reflections, which affects the reliability of imaging systems.
Innovation Solution
A trolley-type vehicle monitor device is equipped with an imaging system that includes reference photographic subjects and an illumination device, allowing for accurate day or night determination by comparing luminance values of these subjects, even in changing lighting conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the AGC circuit automatically adjusts the luminance level in the entire image, then the luminance intensity is maintained within a constant range, but the determination accuracy in day or night determination deteriorates due to large variations in luminance average value in specific areas
Solution Approach 1:
The patent divides the image into multiple specific areas (first specific area and second specific area) and calculates luminance average values separately for each area. This segmentation allows the system to capture local luminance characteristics rather than relying on a single global average, thereby maintaining determination accuracy even when the AGC circuit adjusts overall luminance levels.
Solution Approach 2:
The patent applies different luminance evaluation approaches to different specific areas within the image. By focusing on local luminance average values in predetermined areas rather than the entire image, the system preserves the ability to accurately determine day or night conditions despite global luminance adjustments made by the AGC circuit.
2Device complexity
If the day or night determination is based on luminance average value in a single area, then the processing is simple, but the accuracy deteriorates when the vehicle travels between flat ground and valley side or when street lamps reflect
Solution Approach 1:
The patent segments the image into multiple specific areas and calculates luminance average values for each segment. This approach maintains relatively simple processing while improving accuracy by comparing luminance characteristics across multiple areas rather than relying on a single area's luminance value.
Solution Approach 2:
The patent combines luminance information from multiple specific areas to make the day or night determination. By merging the luminance average values from different areas, the system achieves more robust and accurate determination that is not easily affected by local variations such as street lamp reflections or terrain changes.
3Measurement precision
If the ground area is set within the shooting image for day or night determination, then the determination accuracy improves, but it becomes impossible in trolley type transportation vehicles where the monitoring object is the pantograph
Solution Approach 1:
The patent establishes a universal method for day or night determination that works across different vehicle types and monitoring scenarios. By using multiple specific areas within the shooting image itself rather than requiring external reference areas like ground areas, the system becomes adaptable to both conventional vehicles and trolley type transportation vehicles where the pantograph is the monitoring object.
Solution Approach 2:
The patent introduces specific areas within the image as intermediary regions for luminance evaluation. These intermediary areas serve as proxies for ground areas, allowing the system to perform accurate day or night determination without requiring actual ground areas to be visible in the shooting image, thus enabling application to trolley type vehicles.
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 enhances the accuracy of day or night determination, improving the recognition of overhead lines and current collectors by adjusting image processing parameters based on the determined mode, thereby enhancing operational safety and reliability.
Implementation Method 1
An image signal in accordance with light and dark (a luminance level) of light inputted into a camera light-receiving part is outputted
Implementation Method 2
almost all of cameras to be sold on the market have an AGC (Automatic Gain Control) circuit in advance housed therein, the AGC circuit outputting an image signal the luminance intensity (the width of light and dark) of which is adjusted within a constant range by increasing a gain when the light quantity is weak and decreasing the gain when the light quantity is excessive
Data Source
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AI summary
A monitor device (11) is provided with an imaging device (21) that shoots an overhead line (1) and a current collector (10), and a controller (26) that processes an image shot by the imaging device (21). The controller (26) includes a day or night determination processing section (29) that determines day or night of the image shot by the imaging device (21), and an image processing section (32) that switches a parameter for recognizing the overhead line (1) and the current collector (10) in the image by executing image processing different in the daylight and at night based upon the result of the day or night determination determined by the day or night determination processing section (29). Further, there are provided reference photographic subjects (24) to be shot by the imaging device (21) in positions different from the overhead line (1) and the current collector (10) in an image area to be shot, and the day or night determination processing section (29) in the controller (26) performs the determination of day or night based upon a luminance average value of the reference photographic subjects (24) inputted into an image input section (27).