Photoacoustic Image Generation via Frequency-Selective Pixel Replacement

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Solution Overview

Problem

Photoacoustic image generation faces difficulties in combining low frequency and high frequency components effectively, leading to challenging observations due to fragmented images when simply overlaying low frequency and high frequency images.

Innovation Solution

A photoacoustic image generation apparatus and method that generates separate images based on low and high frequency components using filters and combines them by placing high frequency pixel values on low frequency pixels with threshold values, enhancing image clarity and detail observation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If only low frequency components are displayed, then large-diameter blood vessels are easily observable, but details are lost

Engineering Contradiction:

Improveobservability of large-diameter blood vesselsVSAvoidloss of detailed information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The photoacoustic image is segmented into multiple frequency bands (low frequency, mid frequency, high frequency) which are then processed and combined separately. This segmentation allows each frequency component to be optimized for its specific contribution - low frequencies for overall structure and high frequencies for detailed features - thereby resolving the contradiction between observing large vessels and preserving details.

Inventive Principle:

Principle #1Segmentation

2Loss of information

If only high frequency components are displayed, then details become noticeable, but fragmentation of blood vessels occurs

Engineering Contradiction:

Improvepreservation of detailed informationVSAvoidintegrity of blood vessel structure

Core Design Contradiction:

Loss of informationVSStability of the object's composition

Solution Approach 1:

Multiple frequency-band images are merged using a combination strategy where low frequency components provide the stable structural foundation and high frequency components add detailed information. The merging process integrates these components to produce a unified image that maintains blood vessel integrity while preserving detailed features, thus resolving the contradiction between detail preservation and structural stability.

Inventive Principle:

Principle #5Merging (Combining)

3Loss of information

If high frequency image is simply placed on low frequency image, then both frequency components are included, but fragmented blood vessels are superposed creating difficult-to-observe images

Engineering Contradiction:

Improveinclusion of all frequency componentsVSAvoidease of image observation

Core Design Contradiction:

Loss of informationVSEase of operation

Solution Approach 1:

Different regions of the image are assigned different quality characteristics based on their frequency content. Low frequency regions provide smooth background information while high frequency regions contribute detailed features only where appropriate. This local quality assignment prevents the uniform superposition of fragmented high frequency details over the entire low frequency image, thereby improving observability while retaining all frequency information.

Inventive Principle:

Principle #3Local quality

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 improves image observation by compensating for information gaps in low frequency images with high frequency details, reducing the complexity of observing blood vessels and other structures with enhanced recognition characteristics.

Implementation Method 1

photoacoustic imaging, which images the inside of a living body by utilizing photoacoustic effects... living tissue absorbs energy of the pulsed laser light, and ultrasound (photoacoustic signals) is induced by adiabatic expansion caused by the energy

Methodology Applied

Scientific EffectPhotoacoustic effect: Photoacoustic Effect

Implementation Method 2

a first filter means that generates the first photoacoustic image by applying a low-pass filter that at least attenuates a component of higher than a predetermined frequency to the third photoacoustic image

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Implementation Method 3

a second filter means that generates the second photoacoustic image by applying a high-pass filter that at least attenuates a component of less than or equal to a predetermined frequency to the third photoacoustic image

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Data Source

PatentUS9888856B2Photoacoustic image generation apparatus, system and method

Publication Date: 2018.02.13 FUJIFILM SONOSITE INC

AI summary

A photoacoustic wave induced in a subject to be examined by illumination of the subject to be examined with light is detected. A first photoacoustic image corresponding to a frequency component less than or equal to a predetermined frequency and a second photoacoustic image corresponding to a frequency component higher than a predetermined frequency are generated based on a detection signal of the detected photoacoustic wave. The first photoacoustic image and the second photoacoustic image are combined together by placing, on a pixel in the first photoacoustic image the pixel value of which is less than or equal to a threshold, a pixel in the second photoacoustic image corresponding to the pixel in the first photoacoustic image.