OPTICAL SPEED SENSING SYSTEM
First Claim
1. An apparatus for determining a rotational speed of a rotating object without requiring a reflective target on the object, the apparatus comprising:
- a light source for transmitting a collimated light beam having a selected wavelength directly at the rotating object, wherein light signals are reflected from the rotating object, an optical system for focusing the reflected light signals onto a detector having a single detection region, wherein the detector detects the focused light signals and generates electrical signals based thereon, a power source for providing power to the apparatus, and an analyzer including at least one Fourier Transform function for transforming the electrical signals, the analyzer for processing the electrical signals representative of the reflected light signals, determining, and outputting the rotational speed of the object from the transformed signals.
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Accused Products
Abstract
An apparatus for determining the rotational speed of an object returning diffuse reflections where no reflective singularity exists on the object or no clearly distinct light pulse is produced. A light source illuminates a target area on the object. An optical system receives the reflected light, selectively filters by wavelength, and focuses the light on a detector for signal processing. The reflected light signals may be a series of complex patterns that repeat once per revolution. A Fourier Transform with additional processing enhancements is performed on the signals and used as a basis to calculate the speed of the object. The signal processing may be automated, resulting in a speed (RPM) solution being displayed for the operator of the device.
143 Citations
25 Claims
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1. An apparatus for determining a rotational speed of a rotating object without requiring a reflective target on the object, the apparatus comprising:
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a light source for transmitting a collimated light beam having a selected wavelength directly at the rotating object, wherein light signals are reflected from the rotating object, an optical system for focusing the reflected light signals onto a detector having a single detection region, wherein the detector detects the focused light signals and generates electrical signals based thereon, a power source for providing power to the apparatus, and an analyzer including at least one Fourier Transform function for transforming the electrical signals, the analyzer for processing the electrical signals representative of the reflected light signals, determining, and outputting the rotational speed of the object from the transformed signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for determining a rotational speed of a rotating object comprising the steps of:
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(a) providing an apparatus including a light source, an optical system, a detector having a single detection region, a power source for providing power to the apparatus, and an analyzer including a Fourier Transform function operable to perform at least one Fourier Transform, (b) transmitting a collimated light beam having a selected wavelength with the light source directly at the rotating object, wherein light signals are reflected from the rotating object, (c) focusing the reflected light signals onto the single detection region of the detector, (d) detecting the focused light signals with the detector, (e) generating electrical signals based on the light signals detected with the single detection region of the detector, (f) processing the electrical signals with the analyzer including at least one operation with the Fourier Transform function, (g) determining the rotational speed of the rotating object with the analyzer from the processed electrical signals, and (h) outputting the rotational speed of the object to a user with the apparatus. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An apparatus for determining a rotational speed of a rotating object comprising:
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optical processing components, including;
a light source for transmitting a collimated light beam having a selected wavelength at the rotating object, wherein light signals are reflected from the rotating object, and an optical system for focusing the reflected light signals onto a detecting means having a single detection region, wherein the detecting means is operable to detect the focused light signals and generate a detected light signal based on light detections with the single detection region of the detector, an analyzer for digitizing the detected light signal to produce a digitized detected light signal, converting the digitized detected light signal from a first domain to a second domain providing a spectrum, analyzing the spectrum to determine the rotational speed of the rotating object, and producing an output indicating the rotational speed of the rotating object, and a power source for providing power to the apparatus. - View Dependent Claims (19, 20, 21)
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22. An optical speed sensing system for manually determining the speed of a rotating object without requiring a reflective element on the object, the system comprising:
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a collimated light source of a selected wavelength for illuminating an area of the rotating object, wherein light signals are reflected from the rotating object, an optical system for collecting the reflected light signals of the selected wavelength and rejecting light signals other than the selected wavelength, wherein the collected light signals are converted to electrical signals, a conversion means for digitizing the electrical signals, an analysis means including a Fourier Transform function for generating power spectral density data from the digitized electrical signals, the power spectral density data being stored in a first memory, a means for displaying a speed spectrum to a user of the system, wherein the speed spectrum is generated from the power spectral density data stored in the first memory and, a calculation means for calculating the rotational speed of the rotating object according to a frequency peak in the displayed speed spectrum, the frequency peak being selected by a user of the system.
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23. An optical speed sensing system for automatically determining the speed of a rotating object without requiring a reflective element on the object, the system comprising:
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a collimated light source of a selected wavelength for illuminating an area on the rotating object, wherein light signals are reflected from the rotating object, an optical system for collecting the reflected light signals of the selected wavelength and rejecting light signals other than the selected wavelength, wherein the collected light signals are converted to electrical signals, a conversion means for digitizing the electrical signals, an analysis means including;
a Fourier Transform means for applying a first Fourier Transform function to generate power spectral density data from the digitized electrical signals, the power spectral density data being stored in a first memory, and for applying a second Fourier Transform function converting the power spectral density data to autocorrelation data, the autocorrelation data being stored in a second memory, and an algorithm means operable upon the stored autocorrelation data, wherein the algorithm means includes criteria for automatic determination of the rotational speed of the rotating object from the autocorrelation data, and means for displaying a speed spectrum to a user of the system, wherein the speed spectrum is generated from the power spectral density data stored in the first memory, the display of the speed spectrum indicating the rotational speed of the rotating object. - View Dependent Claims (24, 25)
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Specification