초록 ▼

A distance measuring system comprises first and second transducers, and an ultrasound ranging subsystem coupled to the first and second transducers for performing a plurality of distance measurements between the first and second transducers. The distance measurement system can have various applicati

A distance measuring system comprises first and second transducers, and an ultrasound ranging subsystem coupled to the first and second transducers for performing a plurality of distance measurements between the first and second transducers. The distance measurement system can have various applications, including medical applications, in which case, the first and second transducers can be mounted on a catheter. The distance measuring system further comprises a filter coupled to the ultrasound ranging subsystem for filtering ultrasound interference from the plurality of distance measurements (such as, e.g., eight), and outputting a distance based on the filtered distance measurements. The filter filters the ultrasound interference by selecting one of the plurality distance measurements, in which case, the outputted distance is the selected distance measurement. Because the ultrasound interference will typically represent itself as the shortest distance measurement, the selected distance measurement is preferably greater than the minimum distance measurement (such as, e.g., the maximum distance measurement), thereby filtering the ultrasound interference out.

대표청구항 ▼

What is claimed is: 1. A distance measuring system, comprising: first and second transducers; an ultrasound ranging subsystem coupled to the first and second transducers for performing straight path distance measurements between the first and second transducers; and a filter coupled to the ultrasou

What is claimed is: 1. A distance measuring system, comprising: first and second transducers; an ultrasound ranging subsystem coupled to the first and second transducers for performing straight path distance measurements between the first and second transducers; and a filter coupled to the ultrasound ranging subsystem for receiving the distance measurements, comparing the distance measurements to each other, determining a relative ordering of the distance measurements based on the comparison, selecting one of the distance measurements based on the determined distance measurement ordering, and outputting the selected distance measurement as the distance between the first and second transducers. 2. The system of claim 1, wherein the distance measurement is only selected if it is greater than the minimum distance measurement. 3. The system of claim 1, wherein the distance measurement is only selected if it is the maximum distance measurement. 4. The system of claim 1, wherein the number of distance measurements compared is greater than 2. 5. The system of claim 1, wherein the ultrasound ranging subsystem further comprises: a pulse generator coupled to the first transducer for generating and transmitting transmit pulses to the first transducer; a threshold detector coupled to the second transducer for detecting receive pulses from the second detector; and measurement means coupled to the pulse generator and the threshold detector; wherein, for each distance measurement, the measurement means triggers the pulse generator to generate and transmit a transmit pulse to the first transducer, measures the elapsed time between transmission of the transmit pulse and detection of a receive pulse by the threshold detector, and generates the distance measurement based on the measured elapsed time. 6. The system of claim 5, wherein the measurement means comprises a digital counter for measuring the elapsed time. 7. The system of claim 1, further comprising a catheter on which at least one of the first and second transducers is mounted. 8. The system of claim 1, further comprising a processor coupled to the filter for determining the position of one of the first and second transducers in a three-dimensional coordinate system at least partially based on the outputted distance measurement. 9. A distance measuring system, comprising: first and second transducers; an ultrasound ranging subsystem coupled to the first and second transducers for performing straight path distance measurements between the first and second transducers; and a filter coupled to the ultrasound ranging subsystem for sequentially receiving the distance measurements, filtering ultrasound interference from the last N distance measurements, and outputting one of the N distance measurements as the distance between the first and second transducers based on the filtering of the distance measurements, wherein N is greater than 2. 10. The system of claim 9, wherein the ultrasound interference filtering comprises comparing the N distance measurements, and wherein the distance measurement is output based on the distance measurement comparison. 11. The system of claim 10, wherein the ultrasound interference filtering comprises determining a distance measurement that is greater than a minimum of the N distance measurements, and wherein the determined distance measurement is output as the distance between the first and second transducers. 12. The system of claim 9, wherein the ultrasound interference filtering comprises determining a maximum of the N distance measurements, and wherein the determined distance measurement is output as the distance between the first and second transducers. 13. The system of claim 9, wherein N is at least 8. 14. The system of claim 9, wherein the ultrasound ranging subsystem further comprises: a pulse generator coupled to the first transducer for generating and transmitting transmit pulses to the first transducer; a threshold detector coupled to the second transducer for detecting receive pulses from the second detector; and measurement means coupled to the pulse generator and the threshold detector; wherein, for each distance measurement, the measurement means triggers the pulse generator to generate and transmit a transmit pulse to the first transducer, measures the elapsed time between transmission of the transmit pulse and detection of a receive pulse by the threshold detector, and generates the distance measurement based on the measured elapsed time. 15. The system of claim 14, wherein the measurement means comprises a digital counter for measuring the elapsed time. 16. The system of claim 9, further comprising a catheter on which at least one of the first and second transducers is mounted. 17. The system of claim 9, further comprising a processor coupled to the filter for determining the position of one of the first and second transducers in a three-dimensional coordinate system at least partially based on the outputted distance measurement. 18. A distance measuring system, comprising: first and second transducers; an ultrasound ranging subsystem coupled to the first and second transducers for performing distance measurements between the first and second transducers; and a filter coupled to the ultrasound ranging subsystem for sequentially receiving the distance measurements, comparing the last N distance measurements to each other, determining a relative ordering of the last N distance measurements based on the comparison, detecting and comparing ultrasound interference against a threshold, selecting one of the last N distance measurements based on the determined distance measurement ordering if the detected ultrasound interference is above the threshold, selecting the Nth distance measurement if the detected ultrasound is below the threshold, and outputting the selected distance measurement as the distance between the first and second transducers. 19. The system of claim 18, wherein the selected one of the last N distance measurements must be greater than a minimum of the last N distance measurements. 20. The system of claim 18, wherein the selected one of the last N distance measurements must be the maximum of the last N distance measurements. 21. The system of claim 18, wherein N is greater than 2. 22. The system of claim 18, wherein N is at least 8. 23. The system of claim 18, wherein the ultrasound ranging subsystem further comprises: a pulse generator coupled to the first transducer for generating and transmitting transmit pulses to the first transducer; a threshold detector coupled to the second transducer for detecting receive pulses from the second detector; and measurement means coupled to the pulse generator and the threshold detector; wherein, for each distance measurement, the measurement means triggers the pulse generator to generate and transmit a transmit pulse to the first transducer, measures the elapsed time between transmission of the transmit pulse and detection of a receive pulse by the threshold detector, and generates the distance measurement based on the measured elapsed time. 24. The system of claim 23, wherein the measurement means comprises a digital counter for measuring the elapsed time. 25. The system of claim 18, further comprising a catheter on which at least one of the first and second transducers is mounted. 26. The system of claim 18, further comprising a processor coupled to the filter for determining the position of one of the first and second transducers in a three-dimensional coordinate system at least partially based on the outputted distance measurement. 27. The system of claim 18, wherein the ultrasound interference detection and comparison comprises computing a distance variation of the last N distance measurements and comparing the distance variation to a threshold value. 28. The system of claim 27, wherein the distance variation is the difference between the maximum and minimum of the last N distance measurements. 29. The system of claim 27, wherein the distance variation is the variance of the last N distance measurements. 30. The system of claim 27, wherein the distance variation is the second derivative of the last N distance measurements. 31. An ultrasound system, comprising: a first ultrasound-based subsystem for performing a distance measuring function; and a second ultrasound-based subsystem for generating ultrasound energy used to perform a function different from the distance measuring function; wherein the first ultrasound-based subsystem includes: first and second transducers; an ultrasound ranging subsystem coupled to the first and second transducers for performing distance measurements between the first and second transducers; and a filter coupled to the ultrasound ranging subsystem for receiving the distance measurements, and filtering the ultrasound energy from the distance measuring function by comparing the distance measurements to each other, and selecting one of the distance measurements based on the comparison. 32. The system of claim 31, wherein the filter outputs the selected distance measurement as the distance between the first and second transducers. 33. The system of claim 32, wherein the distance measurement is only selected if it is greater than the minimum distance measurement. 34. The system of claim 32, wherein the distance measurement is only selected if it is the maximum distance measurement. 35. The system of claim 31, wherein the number of distance measurements is greater than 2. 36. The system of claim 35, wherein the measurement means comprises a digital counter for measuring the elapsed time. 37. The system of claim 31, wherein the ultrasound ranging subsystem further comprises: a pulse generator coupled to the first transducer for generating and transmitting transmit pulses to the first transducer; a threshold detector coupled to the second transducer for detecting receive pulses from the second detector; and measurement means coupled to the pulse generator and the threshold detector; wherein, for each distance measurement, the measurement means triggers the pulse generator to generate and transmit a transmit pulse to the first transducer, measures the elapsed time between transmission of the transmit pulse and detection of a receive pulse by the threshold detector, and generates the distance measurement based on the measured elapsed time. 38. The system of claim 31, further comprising a catheter on which at least one of the first and second transducers is mounted. 39. The system of claim 31, further comprising a processor coupled to the filter for determining the position of one of the first and second transducers in a three-dimensional coordinate system at least partially based on the outputted distance measurement. 40. The system of claim 31, wherein second ultrasound-based subsystem is an ultrasound imaging subsystem. 41. The system of claim 40, wherein the ultrasound energy filtering comprises comparing the N distance measurements to each other, and wherein the distance measurement is output based on the distance measurement comparison. 42. The system of claim 40, wherein N is at least 2. 43. The system of claim 42, wherein the measurement means comprises a digital counter for measuring the elapsed time. 44. The system of claim 40, further comprising a catheter on which at least one of the first and second transducers is mounted. 45. The system of claim 40, further comprising a processor coupled to the filter for determining the position of one of the first and second transducers in a three-dimensional coordinate system at least partially based on the outputted distance measurement. 46. The system of claim 40, wherein second ultrasound-based subsystem is an ultrasound imaging subsystem. 47. The system of claim 40, wherein the ultrasound ranging subsystem further comprises: a pulse generator coupled to the first transducer for generating and transmitting transmit pulses to the first transducer; a threshold detector coupled to the second transducer for detecting receive pulses from the second detector; and measurement means coupled to the pulse generator and the threshold detector; wherein, for each distance measurement, the measurement means triggers the pulse generator to generate and transmit a transmit pulse to the first transducer, measures the elapsed time between transmission of the transmit pulse and detection of a receive pulse by the threshold detector, and generates the distance measurement based on the measured elapsed time. 48. An ultrasound system, comprising: a first ultrasound-based subsystem for performing a distance measuring function; and a second ultrasound-based subsystem for generating ultrasound energy used to perform a function different from the distance measuring function; wherein the first ultrasound-based subsystem includes: first and second transducers; an ultrasound ranging subsystem coupled to the first and second transducers for performing a plurality of distance measurements between the first and second transducers; and a filter coupled to the ultrasound ranging subsystem for sequentially receiving the distance measurements, filtering the ultrasound energy from the last N distance measurements and outputting one of the N distance measurements as the distance between the first and second transducers based on the filtering of the distance measurements. 49. The system of claim 48, wherein the ultrasound energy filtering comprises determining a distance measurement that is greater than a minimum of the N distance measurements, and wherein the determined distance measurement is output as the distance between the first and second transducers. 50. The system of claim 48, wherein the ultrasound energy filtering comprises determining a maximum of the N distance measurements, and wherein the determined distance measurement is output as the distance between the first and second transducers.