Ultrasound beamformer-based channel data compression

#The present embodiments relate to medical diagnostic ultrasound imaging. In particular, channel data compression is provided for ultrasound imaging using software.

#As computer processing power increases, ultrasound systems have been gradually transferring hardware signal processing functionality into software. Software-based signal processing is advantageous for flexible development, better maintainability, cost, and quick experimentation. The primary problem facing a software-based ultrasound system is getting large amounts of single-element, raw channel data from an ultrasound front-end into a computer memory for processing. When the system channel count is high (e.g., 128 elements or channels), transfer data rates may be extremely high and challenge the maximum data rates of even the most state of the art computer bus. To deal with such large transfer rates, additional or custom hardware may be used, but this defeats the primary purpose of hardware reduction. The maximum acoustic frame rate and/or the number of channels may be reduced, but this results in decreased image quality.

#By way of introduction, the preferred embodiments described below include methods, computer readable media, instructions, and systems for ultrasound imaging. To increase the amount of data transferred, ultrasound beamformer-based channel data compression is provided. A beamformer is used to compress instead of or in addition to traditional beamformation. The compression reduces the data bandwidth while allowing reconstruction of the original channel data.

#The components and the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the Figures, like reference numerals designate corresponding parts throughout the different views.

#FIG. 1 is a block diagram of one embodiment of a system for ultrasound imaging;

#FIG. 2 is a block diagram of one embodiment of a receive beamformer for ultrasound beamformer-based channel data compression;

#Ultrasound raw channel data is compressed for transmission to a processor or system for ultrasound imaging. Any basis function set, such as a Fourier basis, may be used. The compression is achieved in the lateral dimension or across the array, allowing use of a conventional delay-and-sum beamformer. When the number of frequency domain ‘beams’ or amount of frequency domain data representing the channel data is less than the number of channels, an effective compression is achieved compared to directly transferring raw channel data. Raw channel data compression of 3:1 or more may be provided. Commonly used hardware (i.e., a delay-and-sum beamformer) performs lateral encoding of the raw channel data to reduce the total amount of raw channel data sent over the PCIExpress or other bus to a computer.

#This re-use of existing hardware may keep development time and costs low and/or allow the use of new beamforming technologies, such as frequency domain beamforming applied in software. For Fourier beamforming, the beamformer-created Fourier data may be Fourier transformed over time or depth, providing a two-dimensional transform of the channel data. Beamformation may then be provided in the two-dimensional Fourier domain.

#In one embodiment, multiple channels of raw data from a transmission event are sampled and sent to a hardware delay-and-sum beamformer. The beamformer applies a combination of complex apodization weights and/or lateral delay profiles that allow the beamformer to form ‘beams’ in the frequency space of the raw channel data, effectively Fourier encoding the data. Other apodization and/or delay profiles may be used to implement other basis functions that substantially enable recovery of channel information. Lossless or lossy recovery of the channel data may be used or the data may be further transformed for beamforming from a domain other than the spatial-temporal domain of the channel data.