Method and device for optically measuring distance or speed
AssigneeLeica Geosystems AG
InventorHartmut Ehbets
Life of this patent
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Abstract
The invention relates to a method for measuring a distance-related variable such as distance, speed or acceleration, or for levelling. An emitting device (1-6) comprising at least one microlaser (3) is used as an emitter, and the beam reflected off an object surface is received and evaluated for measurement. A beam is emitted and evaluated after being received, in a substantially simultaneous manner in at least two different wavelengths. Preferably, said method is carried out by means of a device whereby the microlaser (3) in the form of a passively pulsating microlaser (3) emits at least two different wavelengths. A receiver (15, 40) for the laser beam reflected off an object is arranged downstream from the evaluating device (41).
Claims27
A method for optically measuring distance or speed, comprising:
- providing a transmitting arrangement having at least one microchip laser that is adapted to emit radiation in the form of pulses and a frequency converter that converts a portion of the radiation emitted by said at least one microchip laser to a different wavelength, wherein said transmitting arrangement emits radiation in the form of a common beam toward an object, wherein said common beam being a diffraction-limited Gaussian beam of the at least two wavelengths (λ1, λ2), the common beam of the radiation reflected by a surface of an object being received and evaluated, wherein the transmitting arrangement emits at least radiation having a wavelength in the invisible range (λ1), said wavelength in the invisible range and radiation of another wavelength (λ2) simultaneously with the radiation having a wavelength (λ1) wherein the further radiation of another wavelength (λ2) is in the visible range;
- evaluating together the information available after the at least two wavelengths (λ1, λ2) have been received;
- and
- monitoring the radiation of visible radiation and switching off at least that part of the transmitting arrangement which emits the invisible radiation if said monitoring determines that the visible radiation is absent.
A device for optically measuring distance or speed or for a levelling device, comprising:
- a transmitting arrangement emitting a laser beam via an object lens;
- a receiver for the laser beam reflected by an object and passed through said object lens;
- wherein said transmitting arrangement comprises at least one microchip laser that is adapted to emit radiation in the form of pulses and a frequency converter, said frequency converter adapted to convert a portion of the radiation emitted by said at least one microchip laser to a different wavelength;
- said transmitting arrangement emitting a common beam made up of at least two different wavelengths (λ1, λ2) emitted simultaneously, one of said wavelengths in the infrared range and one of said wavelengths in the visible range, said beam being a diffraction-limited Gaussian beam of different wavelengths (λ1, λ2);
- said lens being formed for emission of the diffraction-limited, Gaussian beam;
- and
- evaluating means downstream of said receiver for evaluating the at least two different wavelengths (λ1, λ2);
- and
- monitoring means for monitoring the radiation of visible radiation and a switching stage for switching off at least that part of said transmitting arrangement which emits the invisible radiation in response to said monitoring means determining that visible radiation is absent.
A device for optically measuring distance or speed or for a levelling device, comprising:
- a transmitting arrangement emitting a laser beam via an object lens;
- a receiver for the laser beam reflected by an object and passed through said object lens;
- wherein said transmitting arrangement comprises at least one microchip laser that is adapted to emit radiation in the form of pulses and a frequency converter, said frequency converter adapted to convert a portion of the radiation emitted by said at least one microchip laser to a different wavelength;
- said transmitting arrangement emitting a common beam made up of at least two different wavelengths (λ1, λ2) emitted simultaneously, one of said wavelengths in the infrared range and one of said wavelengths in the visible range, said beam being a diffraction-limited Gaussian beam of different wavelengths (λ1, λ2);
- said lens being formed for emission of the diffraction-limited, Gaussian beam;
- and
- evaluating means downstream of said receiver for evaluating the at least two different wavelengths (λ1, λ2);
- and
- a beam splitter for separating the two wavelength components, and an antireflection screen arranged outside an image plane of said receiver upstream of said receiver.
Dependencies are inferred from the claim text.