Abstract: A discrete pixel image field of view is expanded by correction of filtered and processed image data. The raw image data is processed through at least one continuous domain filter. Roll off at limits of a linear range of the filter result in loss or degradation of image data in the transition region. The filtered image data is digitized and the resulting values are stored in discrete frequency value bins. Correction values are applied to the image data in the discrete bins of the transition region to correct the filter roll off. At least a portion of the corrected data is added to the field of view data employed in the image reconstruction. The technique permits as much as several percent of the field of view to be recuperated from the transition regions.

Abstract: A method for configuring an ultrasound imaging system having a programmable signal processor and an operator interface. Application codes for programming the signal processor to process signals in accordance with respective imaging modes are stored in memory. A user operates an operator interface to select one of the plurality of imaging modes. The master controller programs the signal processor with the application code corresponding to the selected imaging mode. The signal processor is programmable to process signals in the B mode, M mode, color flow imaging mode and Doppler imaging mode. Preferably, the programmable signal processor is an array of digital signal processor chips. Incoming vector data is partitioned amongst the respective digital signal processor chips. The processed vector segments are then recombined to form a vector of image data for display.

Abstract: Methods and apparatus for reducing the amount of computation required by nonlinear operations in medical ultrasound imaging by using lower-order polynomials to approximate the nonlinear functions. The method can be applied to envelope detection, phase detection, logarithmic compression and other nonlinear functions. Various pre-processing techniques (e.g., pre-reducing the data range and pre-dividing an entire range of the input into a number of subranges) can optionally be used prior to the polynomial approximation to achieve better accuracy, further reduce the polynomial order, and/or simplify the implementation.

Abstract: A method using a progressive sampling rate technique to maintain the sampling rate at the Nyquist frequency of the I/Q data through a tunable equalization bandpass filter in the front end of the imager and then increasing the sampling rate via axial interpolation to prevent aliasing during the nonlinear detection process. If an envelope detector is used, the bandwidth of the detector output should be approximately double that of the I/Q data. In this case, the sampling rate is doubled (or more) by axial interpolation before envelope detection. A 2-point linear interpolator can be used. Depending on the application, this axial interpolator can be turned on or off automatically by the system. After detection, the signal can be low-pass filtered to restrict the speckle bandwidth prior to log compression.

Abstract: A method for reducing speckle artifact in an ultrasound image using a two-dimensional median filter having a diamond-shaped five-point kernel. The entire pixel image data is passed through the filter in a manner such that the center point of the kernel is effectively stepped down each range vector in sequence. The magnitudes of the pixel data at each of the five points in the kernel are compared and the value which has the middle magnitude is adopted as a new pixel value, which is substituted for the old pixel value at the center point. After a new filtered vector has been formed from the new pixel values produced at successive center points by stepping down one acoustic vector, the kernel is shifted by one vector and stepped down range again. This process continues through the entire set of vectors until a new set of filtered vectors is formed. This filter will remove speckle holes on the order of one pixel in size while preserving good edge definition.

Abstract: An X-ray apparatus has a motor for moving its components in different directions. A collision sensor is formed by a bladder attached to a component of the apparatus and deformation of the bladder produces a change in the pressure of air within the bladder. The bladder has an air vent to the atmosphere which can be sealed by operation of a valve. A pressure sensor produces two control signals when the pressure within the bladder exceeds first and second threshold levels respectively. The second threshold level is greater in magnitude than said first threshold level. The first control signal closes the valve and causes a motor control circuit to discontinue any application of electricity to the motor. The second control signal opens a switch through which electricity normally flows to the motor. A mechanism also is provided to simulate a collision by compressing the bladder to test the operation of the detection system.