Electro-Optical Distance Measuring Method Using Pulsed Laser Discrimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electro-optical distance measuring devices face limitations in measuring distances to multiple objects simultaneously and accurately, especially when objects are close to each other, due to mechanical optical path switching and the need for complex and costly circuit arrangements.
Innovation Solution
An electro-optical distance measuring method that projects pulsed laser beams with a spreading angle from multiple known positions, discriminates and detects reflected lights, and measures distances and coordinates of multiple objects using a single operation, with preliminary and main measurements to optimize detection timing and reduce response delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical optical path switching is used to measure distances to multiple objects, then the device can perform distance measurements, but the measurement speed and responsiveness are limited
Solution Approach 1:
The patent replaces mechanical optical path switching with electrical signal processing. Instead of physically switching optical paths using mirrors or prisms, the system uses a single optical path with photodetectors that electrically distinguish between multiple objects based on the timing and characteristics of reflected light signals. This eliminates mechanical moving parts and enables faster, more reliable measurements.
Solution Approach 2:
The patent segments the measurement process into distinct temporal phases for different objects. By measuring distances to multiple objects in sequence with precise timing control, the system distinguishes between objects without mechanical switching. The photodetector records signals at different time intervals corresponding to different object distances, allowing the system to identify and measure each object separately through temporal segmentation rather than spatial switching.
2Adaptability or versatility
If complex circuit arrangements are used to measure distances to multiple objects simultaneously, then multiple measurements can be performed, but the device becomes costly and complicated
Solution Approach 1:
The patent employs a universal measurement circuit that can identify and measure multiple objects using the same hardware infrastructure. A single photodetector and processing unit handle measurements for all objects by analyzing temporal patterns in the reflected light signals. This multi-functional approach eliminates the need for separate dedicated circuits for each object, reducing overall device complexity while maintaining versatility.
Solution Approach 2:
The system uses the reflected light signals themselves as the identifying characteristic for different objects. Instead of requiring complex external identification circuits, the measurement system exploits the natural temporal variation of light return times from objects at different distances. The photodetector and processing unit automatically distinguish between objects based on their inherent optical reflection characteristics, making the system self-identifying without additional complex circuitry.
3Area of stationary object
If objects are positioned close to each other, then the measurement range is reduced, but the ability to distinguish and measure each object individually is compromised
Solution Approach 1:
The patent employs periodic measurement cycles where the system sequentially measures distances to different objects in a repeated time-based sequence. By using periodic temporal gating and sequential photodetection, the system can distinguish between closely spaced objects through their distinct time-of-flight signatures. This periodic measurement approach allows high precision for individual objects even when they are positioned close together, as each object's reflection is isolated in the temporal domain rather than requiring large spatial separation.
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
Enables simultaneous measurement of distances and coordinates for multiple objects, improving workability and accuracy while reducing the need for complex circuitry and increasing measurement efficiency.
Implementation Method 1
a laser light source 6, a right-angle reflection mirror 7, an objective lens 8, and a photodetection element 9. The laser light source 6 is a pulsed laser diode (PLD), for instance. From the laser light source 6, a distance measuring light, i.e. a pulsed laser beam, is emitted.
Implementation Method 2
a photodetection element 9. The distance measuring light is deflected by the right-angle reflection mirror 7 and is projected from the electro-optical distance measuring unit 1 through the objective lens 8. The distance measuring light thus projected is reflected by an object to be measured 11, i.e. a prism. The reflected distance measuring light is entered via the objective lens 8 and is deflected and is received by the photodetection element 9.
Implementation Method 3
A half-mirror 12 is arranged on the distance measuring light optical path 4. A part of the distance measuring light is reflected as an internal reference light by the half-mirror 12.
Data Source
AI summary
An electro-optical distance measuring method for measuring a distance to an object to be measured by receiving a reflected light from the object to be measured, comprising a step of projecting a pulsed laser beam with a predetermined spreading angle from each of two or more known positions so that two or more objects to be measured are commonly included, a step of detecting reflected lights from the two or more objects to be measured for each pulsed laser beam by discriminating the reflected lights for each emitted pulse, a step of measuring distances to the two or more objects to be measured from each of the known points based on the results of detection of the discriminated reflected lights, and a step of measuring coordinate positions of the two or more objects to be measured based on the measured distances.