Optical Image Measurement Device Depth Tracking
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Solution Overview
Problem
Current optical image measurement devices face challenges in capturing accurate images of target depth positions, especially when the measurement object moves or has varying depth positions, leading to displacement and reduced measurement sensitivity, particularly in applications like ophthalmology where the fundus oculi's curved surface complicates precise alignment.
Innovation Solution
An optical image measurement device comprising a low-coherence light source, an interference-light generator, a changer to adjust optical path length, a detector, and an analyzer to specify image positions within a frame, with a controller that adjusts the changer to maintain the image in a predetermined position, ensuring accurate capture of target depth positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measurement object moves in the depth direction during measurement, then the measurement position is displaced, but the device cannot capture images at the target depth position
Solution Approach 1:
The reference mirror is made movable in the depth direction, allowing the optical path length of the reference light to be dynamically adjusted. This enables the device to track and compensate for movements of the measurement object in the depth direction, maintaining accurate focus on the target depth position throughout the measurement process
Solution Approach 2:
The system continuously monitors the depth position of the measurement object and adjusts the reference mirror position accordingly. This feedback mechanism ensures that the optical path length difference remains optimized, allowing reliable capture of images at the target depth position even when the object moves
2Measurement precision
If the target depth position moves away from the origin of the Z-direction, then measurement sensitivity lowers, but the device can still capture images
Solution Approach 1:
By making the reference mirror movable, the system can dynamically adjust the optical path length of the reference light to match the current depth position of the measurement object. This maintains high measurement sensitivity across a range of depth positions, not just at the origin
Solution Approach 2:
The system changes the optical path length parameter of the reference light by moving the reference mirror, allowing the measurement device to maintain optimal sensitivity at different depth positions. This enables high-precision measurements across varying depths
3Measurement precision
If a reference mirror is placed at a position corresponding to the depth position to capture images, then alignment precision is required, but the device complexity increases
Solution Approach 1:
Instead of requiring precise static alignment, the reference mirror is made dynamically adjustable. This allows the system to achieve and maintain precise alignment through active control, reducing the need for complex mechanical alignment mechanisms while improving depth position accuracy
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 device effectively captures images at precise target depth positions with high sensitivity, even when the measurement object moves or has varying depth positions, by dynamically adjusting the optical path length, thereby improving image accuracy and stability.
Implementation Method 1
an interference-light generator configured to generate an interference light, by splitting the emitted low-coherence light into a signal light heading toward a measurement object and a reference light heading toward a reference object, and superimposing the signal light passed through the measurement object and the reference light passed through the reference object
Data Source
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AI summary
An optical image measurement device comprises: a light source configured to emit a low-coherence light; an interference-light generator configured to generate an interference light, by splitting the low-coherence light into a signal light and a reference light, and superimposing the signal light passed through a measurement object and the reference light passed through a reference object; a changer configured to change a difference in optical path length; a detector configured to detect the interference light; an image forming part configured to form an image of the measurement object within a predetermined frame based on the result of the detection; an analyzer configured to analyze the image, and specify a position of the image within the frame; and a controller configured to control the changer based on the specified position to change the difference so that an image newly formed is placed in a predetermined position within the frame.