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Ultrasonic audience measurement system and method

  • US 4,644,509 A
  • Filed: 01/23/1986
  • Issued: 02/17/1987
  • Est. Priority Date: 01/23/1986
  • Status: Expired due to Fees
First Claim
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1. A method of identifying a number of people in a monitored area comprising the steps of:

  • collecting a first reflected ultrasonic wave map of the monitored area;

    collecting a second reflected ultrasonic wave map of the monitored area;

    subtracting the first map from the second map to obtain a resulting map;

    processing the resulting map to identify clusters having a minimum intensity;

    calculating a weight coefficient of the identified clusters; and

    comparing the calculated weight coefficients with predefined values.

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