Endoscope Image Processor Stabilizes Brightness via Pulse Width Modulation
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Solution Overview
Problem
The existing endoscope systems struggle to generate an appropriate pseudo pixel signal when pulsed light is modulated by changing the crest value of the pulsed current, leading to fluctuations in brightness that are not targeted, making it difficult to reduce variations within one frame or between successive frames and generate an image suitable for observation.
Innovation Solution
A medical control device with a light source controller that modulates pulsed light by changing the crest value of the pulsed current and an imaging controller that generates a pseudo pixel signal by multiplying the pixel signal for specific horizontal lines by the ratio of exposure amount during the illumination period, considering both crest value and time, to stabilize image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pulsed light is modulated by changing the crest value of pulsed current, then light intensity control is improved, but brightness fluctuations occur that are not targeted through modulation
Solution Approach 1:
The patent changes the parameter used for light modulation from crest value to pulse width. By controlling the duration of the pulsed current pulse rather than its amplitude, the system achieves light intensity control without introducing unwanted brightness fluctuations. This parameter substitution resolves the contradiction by maintaining brightness stability while still enabling effective light modulation for imaging.
2Ease of manufacture
If conventional arithmetic expression is used to generate pseudo pixel signal, then processing simplicity is maintained, but appropriate pseudo pixel signal cannot be generated when light modulation is applied
Solution Approach 1:
The patent modifies the arithmetic expression by changing the parameter from crest value to pulse width. The new expression multiplies the pixel signal by the ratio of the pulse width during illumination to the total exposure amount. This parameter substitution maintains relative processing simplicity while significantly improving pseudo pixel signal accuracy under light modulation conditions.
3Adaptability or versatility
If frame period of image sensor differs from light emission period of pulsed light, then imaging flexibility is improved, but brightness variations occur within one frame or between successive frames
Solution Approach 1:
The patent uses pulse width as the modulation parameter and incorporates it into the pseudo pixel signal generation. By doing so, the system can handle different frame periods and light emission periods without causing brightness variations. The pulse width-based approach naturally adapts to timing differences between the image sensor and light source, maintaining brightness consistency while preserving imaging flexibility.
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
This approach effectively reduces brightness fluctuations, allowing for the generation of images suitable for observation by stabilizing brightness within one frame or between frames, even when light modulation control is executed.
Implementation Method 1
a light source configured to emit pulsed light according to a pulsed current
Implementation Method 2
an image sensor including a plurality of pixels configured to receive light from an object illuminated with the pulsed light and generate a pixel signal
Data Source
AI summary
A medical control device includes: a light source controller configured to modulate pulsed light by changing a crest value of a pulsed current and emit the pulsed light a plurality of times from the light source in one frame; an imaging controller configured to cause an image sensor to sequentially generate a pixel signal at a specific frame rate; and an image processor configured to use a pixel signal obtained by multiplying the pixel signal for specific one frame from each pixel of a specific horizontal line by a ratio of an amount of exposure of specific pulsed light made in the specific one frame to a total exposure amount obtained by adding each exposure amount of all of the pulsed lights exposing the specific horizontal line within the specific one frame including an illumination period of the specific pulsed light.