Dynamic Threshold Noise Reduction in Endoscopic Image Signals
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Solution Overview
Problem
Conventional endoscopic apparatuses face challenges in obtaining high-contrast images due to low light conditions and noise interference, which hinders accurate recognition of affected body parts during procedures.
Innovation Solution
An image signal correction apparatus with a frame memory, difference calculation unit, filter unit, and control unit that processes image signals by calculating differences and adjusting threshold values to suppress noise, particularly in areas of movement, using a CMOS image sensor and a three-dimensional noise reduction circuit to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional image processing is used to emphasize outlines and provide contrast, then image contrast is improved, but noise in the image increases and hinders recognition of affected parts
Solution Approach 1:
The patent implements dynamic threshold adjustment where the threshold value for noise reduction is not fixed but changes based on local image characteristics. The control unit calculates the standard deviation of pixel values in surrounding regions and adapts the threshold accordingly, allowing the noise reduction process to dynamically respond to different image regions and maintain both contrast and noise suppression
Solution Approach 2:
The patent applies different processing strategies to different regions of the image based on local characteristics. By analyzing the standard deviation of pixel values in surrounding regions and applying region-specific threshold values, the system treats high-contrast areas differently from low-contrast areas, preserving important image features while reducing noise in appropriate regions
2Object-generated harmful factors
If noise reduction processing is applied to improve image quality, then noise is reduced, but image contrast may be degraded and over-correction occurs
Solution Approach 1:
The patent incorporates feedback mechanisms where the control unit continuously monitors image characteristics (standard deviation of pixel values) and adjusts the threshold value based on this feedback. This closed-loop approach allows the system to detect when contrast is being degraded and adjust processing parameters to prevent over-correction, maintaining the balance between noise reduction and contrast preservation
3Object-generated harmful factors
If advanced noise reduction circuits are implemented to reduce noise, then noise reduction performance is improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent implements a self-adaptive noise reduction system that automatically adjusts its processing parameters based on local image statistics without requiring complex external control mechanisms. The system calculates standard deviations and threshold values autonomously for each region, eliminating the need for manual parameter tuning or complex adaptive algorithms, thereby reducing overall system complexity while maintaining effective noise reduction
Solution Approach 2:
The patent changes the processing parameters (threshold values) based on local image characteristics such as standard deviation of pixel values. By dynamically adjusting these parameters according to regional variations in the image, the system achieves effective noise reduction without requiring complex circuitry, as the adaptation is achieved through parameter variation rather than structural complexity
Data Source
AI summary
An image signal correction apparatus includes: a frame memory configured to hold input image signals corresponding to a predetermined number of frames; a difference calculation unit configured to calculate a difference signal between an input image signal and each of the image signals held in the frame memory; a filter unit configured to pass a difference signal having a value equal to or smaller than a threshold value; and a control unit configured to change the threshold value of the filter unit in accordance with the value of the difference signal calculated in the difference calculation unit.