Dual Mode Depth Measurement Apparatus for Specular and Textured Surfaces
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Solution Overview
Problem
Current depth measurement technologies, such as depth from defocus and depth from focus, are inadequate for inspecting parts requiring varying measuring ranges and precision, and struggle with characterizing both textured and specular surfaces effectively.
Innovation Solution
A dual mode depth measurement apparatus and method that switches between depth from defocus and depth from focus modes using a light source, controller, processor, lighting optical system, and camera, allowing for depth measurement on both specular and textured surfaces by analyzing speckle patterns to determine the appropriate mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single focusing lens is chosen for depth measurement, then the measuring range and precision are fixed, but this approach is inadequate for inspecting parts requiring different measuring range and depth precision
Solution Approach 1:
The patent employs a tunable lens that can dynamically adjust its focal length to switch between different focusing modes. This dynamic adjustment capability allows the same optical system to adapt to different measuring ranges and precision requirements without requiring multiple fixed lenses, thereby resolving the contradiction between adaptability and complexity
Solution Approach 2:
The tunable lens serves multiple functions by enabling the optical system to perform both depth from defocus and depth from focus measurements. This multi-functionality eliminates the need for separate optical systems for different measurement modes, achieving versatility while maintaining a relatively simple device structure
2Adaptability or versatility
If depth from defocus mode is used for specular surfaces, then depth information can be obtained, but this mode cannot characterize textured surfaces effectively
Solution Approach 1:
The system dynamically switches between depth from defocus mode (for specular surfaces) and depth from focus mode (for textured surfaces) using a tunable lens. This dynamic mode switching enables the system to adapt to different surface types while maintaining high measurement precision for each specific surface category
Solution Approach 2:
The patent changes the optical parameters (focal length, illumination characteristics) to match the surface properties being measured. By adjusting these parameters, the system optimizes its performance for specific surface types, ensuring high precision measurements while expanding overall surface type adaptability
3Adaptability or versatility
If depth from focus mode is used for textured surfaces, then depth information can be obtained, but this mode cannot effectively measure specular surfaces
Solution Approach 1:
The system uses a tunable lens to dynamically switch between measurement modes depending on the surface type. For textured surfaces, it employs depth from focus mode, while for specular surfaces, it switches to depth from defocus mode. This dynamic adaptation ensures high measurement precision across different surface types while achieving broad surface type adaptability
4Adaptability or versatility
If the lighting optical system focuses light into a light spot for depth from defocus mode, then depth information from specular surfaces can be obtained, but the measuring range and precision are fixed
Solution Approach 1:
The patent employs a tunable lens that can dynamically adjust its focal length to change the light spot size and position. This dynamic control enables the system to flexibly adjust measuring range and precision requirements while maintaining a relatively simple optical structure, resolving the contradiction between adaptability and complexity
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 precise depth measurement on objects with varying surface types, adjusting measuring range and precision, and allows for inspection of parts with high precision by selecting the appropriate mode based on surface characteristics.
Implementation Method 1
In the depth from defocus mode, the lighting optical system focuses a light from the light source into a light spot
Implementation Method 2
in the depth from focus mode, it transforms a light from the light source into a uniform light beam
Implementation Method 3
a camera... The processor is for processing a plurality of images
Implementation Method 4
An amount of speckle reflected from the object is analyzed, the amount and nature of speckle determines whether the object has a specular surface or a textured surface
Data Source
AI summary
An apparatus and a method for dual mode depth measurement are provided. The apparatus is used for measuring a depth information of a specular surface in a depth from defocus (DFD) mode or measuring a depth information of a textured surface in a depth from focus (DFF) mode. The apparatus includes a light source, a controller, a processor, a lighting optical system, an imaging optical system, a beam splitter and a camera. The controller is for switching between the depth from defocus mode and the depth from focus mode. The lighting optical system is used to focus a light from the light source on an object surface in the depth from defocus mode, and the lighting optical system is used to illuminate the object surface with a uniform irradiance in the depth from focus mode.