Abstract: A method of producing a simulated 3-dimensional image, the method comprising: assimilating 2-dimensional image data, e.g. from MR image slices; assigning a feature, e.g. gray scale value to each datum; reducing the resolution of each gray scale value of the data; generating a histogram of the reduced resolution gray scale data; performing a fast fuzzy c-means clustering on the histogram data. The resolution of each pixel object in the images may be reduced from 12 bit to 8 bit resolution, and the histogram may be generated from these. Subsequently a value may be assigned for each entry in the histogram, each entry value being equal to the number of objects of any given feature (e.g. gray scale) in the reduced resolution (8 bit) image. The image may be displayed using a novel color blending technique. A 3D image is produced quickly and without supervisory intervention and can be used in endoscopic surgery and in diagnostic methods as well as in understanding healthy anatomical features better.

Abstract: A method of overcoming the ring down problem comprises the steps of generating a reference scan and updating it on the basis of a long term running average and then subtracting that running average from the current A-scan to remove the ring down.

Abstract: A respiration monitor for measuring the respiration of a subject on a mechanical ventilator comprises first transducer means arranged to produce a first signal representative of a respiration status of the subject, second transducer means arranged to produce a second signal representative of a cyclical status of the mechanical ventilator, and processor means arranged to receive said first and second signals and to produce an output signal dependent upon the relative phase of said first and second signals. The invention extends to a method of monitoring, and also to a method of determining the rate at which a mechanical ventilator should be set in order to achieve 1:1 entrainment with spontaneous respiratory efforts.

Abstract: A catheter having an ultrasonic transducer array at its distal end is constructed to overcome the "ringdown" problem by having a conically shaped reflecting interface space from an ultrasonic transducer array in such a way that the "dead space" is contained wholly within the catheter.

Abstract: The internal examination of a human organ is made by means of an ultrasonic probe inserted into the organ, and in one embodiment analogue echo signals from the probe are directly converted into digital signals before any signal processing is carried out. These signals are then stored in a digital computer where they are manipulated to produce a two-dimensional real-time representation of the interior of the organ for display on a terminal or as hard copy. The two-dimensional real-time image may be displayed simultaneously with a three-dimensional nonreal-time image produced by the system.

Abstract: The internal examination of a human organ (3) is made by means of an ultrasonic probe (2) inserted into the organ (3), analogue echo signals from the probe being converted to digital signals (8) which are then stored in a digital computer (10) where they are manipulated to produce a variety of three-dimensional representations of the interior of the organ for display on a terminal (12) or as hard copy (13).