Range Imaging Apparatus Dynamic Illumination Control
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Solution Overview
Problem
Conventional range imaging methods using time-of-flight systems face challenges in achieving high accuracy and speed, particularly when dealing with multiple subjects at different distances, as they often require multiple exposures and adjusted light emission levels, leading to longer generation times and reduced accuracy.
Innovation Solution
A range imaging apparatus that controls signal light emission and exposure based on the position of subjects, using a combination of first and second signal lights to calculate distance values and adjust illumination and exposure parameters dynamically, allowing for high-accuracy distance information to be obtained quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple range images with different exposures are obtained and compared pixel by pixel to generate a highly accurate synthetic range image, then measurement precision is improved, but productivity deteriorates due to longer generation time
Solution Approach 1:
The patent applies preliminary action by performing exposure adjustment based on distance information obtained from a coarse range image before generating the final high-accuracy range image. The signal light emission amount is adjusted in advance according to the distance to each pixel, allowing the main range image generation to proceed with optimized exposure settings without requiring multiple full exposures and pixel-by-pixel comparisons, thus reducing generation time while maintaining accuracy
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the signal light emission amount based on the distance to the subject for each pixel. Instead of using fixed exposure settings or requiring multiple static exposures, the system adaptively changes the illumination intensity according to the measured distance, allowing optimal signal reception for both near and far subjects within a single exposure cycle, thereby improving efficiency without sacrificing measurement precision
2Productivity
If light emission amount is adjusted to a minimum level necessary for measuring distance based on distribution characteristics of distance values, then productivity is improved by reducing exposure time, but measurement precision deteriorates and distance information for all subjects cannot be obtained
Solution Approach 1:
The patent applies local quality by setting different signal light emission amounts for different regions or pixels based on their respective distances to the subject. Instead of using a uniform minimum light level for all pixels, the system locally adapts the illumination intensity to match the specific distance requirements of each pixel, ensuring that both near and far subjects receive adequate lighting for accurate measurement while minimizing overall power consumption and exposure time
3Adaptability or versatility
If a plurality of subjects are present at different distances, then adaptability is improved to handle diverse scenarios, but measurement precision deteriorates when light emission is set to minimum level
Solution Approach 1:
The patent implements parameter changes by dynamically modifying the signal light emission amount parameter based on the distance to each subject. When multiple subjects at different distances are detected, the system adjusts the illumination intensity parameter for each pixel according to its corresponding distance, ensuring that subjects at various ranges all receive appropriate light levels for accurate measurement. This parameter adaptation allows the system to maintain high measurement precision across diverse scenarios with multiple subjects
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
This approach enables high-accuracy range imaging for multiple subjects in a short time by optimizing signal light emission and exposure, improving the S/N ratio and reducing generation time.
Implementation Method 1
a range image generator that calculates a distance value to the subject based on a time difference between illumination start time and light reception start time
Data Source
AI summary
A range imaging apparatus includes a light illuminator that emits signal light from a light source toward a subject; a light receiver that receives light reflecting off the subject; a range image generator that calculates a distance value to the subject based on a time difference between emission and light reception, and generates a range image; a distance value distribution analyzer that calculates a distribution characteristic of the distance value calculated by the range image generator; an illumination controller that adjusts output of the light illuminator; an exposure controller that adjusts exposure by the light receiver; and a signal adjuster that adjusts the illumination controller and the exposure controller based on the distribution characteristic. The signal adjuster adjusts at least one of the illumination controller and the exposure controller for the second signal light based on the distribution characteristic obtained through emission and light reception of the first signal light.