Ultrasound DAM Filtering for Clutter Suppression

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing adaptive weighting techniques in medical ultrasound imaging require access to per-channel data, making hardware implementation difficult and requiring complex computations, which can lead to compromised image contrast due to acoustic clutter and electronic noise.

Innovation Solution

The dual apodization with median (DAM) technique uses complementary apertures to reduce off-axis signals by taking the median value of RF signals from odd and even apertures and a zero or near-zero signal, eliminating the need for per-channel data access and complex computations, thereby improving image contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If adaptive weighting techniques (CF, GCF, PCF, SLSC) are used to reduce acoustic clutter and improve image contrast, then image contrast is improved, but hardware implementation becomes difficult due to requiring per-channel data access and complex computations

Engineering Contradiction:
Improveimage contrastVSAvoidhardware implementation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the aperture into two complementary subsets (odd and even apertures) and processes them separately through parallel beamforming paths. This segmentation allows the system to avoid complex per-channel data access by processing subset sums independently, resolving the contradiction between achieving good image contrast and simplifying hardware implementation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a simplified copy of the beamforming process that operates on pre-summed subset data rather than requiring access to individual channel data. This copying approach maintains the essential functionality of adaptive weighting while dramatically reducing hardware complexity by working with aggregated subset sums instead of raw channel data.

Inventive Principle:
Principle #26Copying

2Object-affected harmful factors

If per-channel data access is implemented to compute weighting masks for adaptive weighting techniques, then acoustic clutter suppression is improved, but computational load and hardware requirements increase significantly

Engineering Contradiction:
Improveacoustic clutter suppressionVSAvoidcomputational load
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The patent performs preliminary beamforming to compute the odd and even aperture subset sums before the adaptive weighting stage. This preliminary action prepares the data in advance, allowing the subsequent clutter suppression to operate on pre-computed values rather than requiring real-time access to individual channel data, thereby reducing computational load while maintaining suppression effectiveness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces odd and even aperture subset sums as intermediary variables that mediate between the raw channel data and the final adaptive weighting computation. These intermediaries aggregate channel information in advance, serving as a bridge that reduces the computational burden of the subsequent weighting operations while preserving the necessary information for effective clutter suppression.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If complex image processing steps (cross-correlation, thresholding, spatial smoothing) are applied to weighting masks, then clutter filtering is improved, but processing time and computational resources increase

Engineering Contradiction:
Improveclutter filteringVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent extracts and eliminates the need for complex image processing steps such as cross-correlation, thresholding, and spatial smoothing by directly incorporating the aperture subset selection and median computation into the beamforming process itself. This extraction removes unnecessary processing stages, achieving effective clutter filtering while significantly reducing processing time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts what would traditionally be harmful complex processing requirements into a beneficial simplified workflow by using the complementary aperture subset structure to naturally suppress clutter through the median operation. The complexity that would normally be needed for clutter filtering is transformed into a straightforward subset-based approach that achieves filtering without time-consuming post-processing steps.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11547389B2Methods and systems for ultrasound contrast enhancement
Publication Date: 2023.01.10 PHILIPS IMAGE GUIDED THERAPY CORP
  • US11547389B2 patent drawing
  • US11547389B2 patent drawing
  • US11547389B2 patent drawing

AI summary

Systems and methods for suppressing off-axis sidelobes and/or clutter, near-field reverberation clutter, and/or grating lobe contributions are disclosed. A dual apodization with median (DAM) filtering technique is disclosed. The dual apodization technique may include summing aligned channel data with apodization functions (406, 412, 414) with complementary apertures applied. Median values for a zero function (RF3) and the resulting signals (RF1, RF2) from the complementary apertures are determined to generate a median value signal (416, MVS). The median value signal is used to generate an ultrasound image with enhanced image contrast. A method of image smoothing of the ultrasound image with enhanced image contrast is also disclosed. The smoothed image may include low frequency components of the ultrasound image with enhanced image contrast and high frequency components of an original image.