Endoscope Processor Device for Accurate Observation Distance Measurement
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Solution Overview
Problem
Accurately acquiring the observation distance in endoscope systems is challenging due to factors like movement in the observation target, foreign matter, and changes in imaging conditions, which can lead to blurred images and inaccurate frequency analysis, scale insertion requirements, and difficulties in determining observation distance at non-magnification.
Innovation Solution
A processor device for endoscopes equipped with an image signal acquisition unit, blood vessel index value calculation unit, and observation distance calculation unit, which calculates blood vessel indices such as density, length, and thickness from image signals to determine the observation distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency analysis is used to acquire observation distance, then observation distance can be obtained, but the analysis becomes inaccurate when blood vessels are blurred due to movement
Solution Approach 1:
The patent introduces blood vessel index values as an intermediary parameter to bridge the gap between image characteristics and observation distance. Instead of directly analyzing frequency (which fails when vessels are blurred), the system calculates blood vessel indices (number, length, area, density) which remain reliable even when vessels are slightly blurred, and uses these indices to infer observation distance through established relationships.
Solution Approach 2:
The patent changes the measurement parameter from frequency-based metrics to blood vessel index-based metrics. By transforming the approach from analyzing frequency components (which collapse when vessels are blurred) to calculating blood vessel indices (which can be derived from intensity profiles and remain stable), the system achieves robust observation distance measurement under varying imaging conditions.
2Measurement precision
If scale is inserted into forceps port to acquire observation distance, then observation distance can be measured, but time and effort for insertion are required
Solution Approach 1:
The system performs self-measurement by utilizing the endoscope's own imaging capabilities to calculate blood vessel indices and determine observation distance automatically. No external scale or additional instrument is needed - the endoscope images itself and the processor device computes the required parameters from the captured images, eliminating the need for manual scale insertion and removal.
Solution Approach 2:
The patent extracts the measurement function from external tools (scales) and integrates it into the endoscope system itself. By extracting the observation distance measurement capability and embedding it within the endoscope's imaging and processing system, the system eliminates the need for separate measurement instruments and their associated handling time.
3Measurement precision
If observation distance is acquired from amount of exposure, then observation distance can be determined, but accuracy decreases when foreign matter changes reflectance
Solution Approach 1:
The patent introduces blood vessel index values as an intermediary that is independent of surface reflectance properties. Instead of relying on exposure amount which is affected by foreign matter reflectance changes, the system calculates blood vessel indices from intensity profiles that are normalized and scaled, making them invariant to surface reflectance variations. This intermediary approach allows observation distance to be determined without being influenced by foreign matter on the observation target surface.
4Measurement precision
If imaging magnification is changed to acquire observation distance, then observation distance can be measured, but measurement cannot be performed at non-magnification
Solution Approach 1:
The patent makes the observation distance measurement function universal by using blood vessel index calculations that work regardless of imaging magnification level. The blood vessel indices (number, length, area, density) can be calculated from images at any magnification setting, and the observation distance can be derived from these indices using consistent relationships, enabling the system to measure observation distance whether the endoscope is in magnification mode or non-magnification mode.
Data Source
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AI summary
There are provided a processor device for an endoscope capable of accurately acquiring an observation distance, an operation method thereof, and a control program. An endoscope system (10) has an endoscope (12), and a light source device (14), and a processor device (16). The endoscope (12) has an imaging sensor (46), and images an observation target and outputs an image signal. The light source device (14) emits illumination light for illuminating the observation target. The processor device (16) includes a measurement image processing unit (64). The measurement image processing unit (64) includes a blood vessel index value calculation section (72) and an observation distance calculation section (74). The blood vessel index value calculation section (72) calculates a blood vessel index value based on the image signal from the endoscope (12). The observation distance calculation section (74) calculates an observation distance from the blood vessel index value calculated by the blood vessel index value calculation section (72).