Detector with a projector for illuminating at least one object

Patent metadata

Field	Value
Publication number	US-12031808-B2
Application number	US-202017431921-A
Country	US
Kind code	B2
Filing date	Feb 20, 2020
Priority date	Feb 20, 2019
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

Described herein is a projector for illuminating at least one object with at least two illumination patterns. The projector includes at least one tunable laser source and at least one diffractive optical element. The projector is configured to generate the at least two illumination patterns each including a plurality of illumination features by controlling at least one property of the tunable laser source. The projector includes at least one control unit. The control unit is configured for controlling the at least one property of the tunable laser source.

First claim

The invention claimed is:

1. A detector ( 110 ) for determining a position of at least one object ( 112 ), the detector ( 110 ) comprising:
at least one projector ( 122 ) for illuminating the object ( 112 ) with at least two illumination patterns ( 124 ), wherein the projector ( 122 ) comprises at least one tunable laser source ( 126 ) and at least one diffractive optical element ( 128 ), wherein the projector ( 122 ) is configured to generate the at least two illumination patterns ( 124 ) each comprising a plurality of illumination features by controlling at least one property of the tunable laser source ( 126 ), wherein the projector ( 122 ) comprises at least one control unit ( 136 ), wherein the control unit ( 136 ) is configured for controlling the at least one property of the tunable laser source ( 126 ), wherein the projector ( 122 ) is operable in at least two emission modes, wherein the control unit ( 136 ) is configured to adjust the emission mode by applying an electrical signal to the tunable laser source ( 126 ), wherein in a first emission mode the tunable laser source ( 126 ) has a first emission wavelength 21 and in a second emission mode the tunable laser source ( 126 ) has a second emission wavelength λ 2 different from the first emission wavelength λ 1 , wherein the at least one projector ( 122 ) is configured to project the at least two illumination patterns ( 124 ) to at least partly differing locations, wherein the at least one control unit ( 136 ) is configured to adjust the emission wavelength in steps or continuously thereby adjusting the location of the at least two illumination patterns ( 124 );
at least one sensor element ( 114 ) having a matrix ( 116 ) of optical sensors ( 118 ), the optical sensors ( 118 ) each having a light-sensitive area ( 120 ), wherein each optical sensor ( 118 ) is designed to generate at least one sensor signal in response to an illumination of its respective light-sensitive area ( 120 ) by a reflection light beam propagating from the object ( 112 ) to the detector ( 110 ), wherein the sensor element ( 114 ) is configured to determine at least one reflection image ( 142 ); and
at least one evaluation device ( 144 ), wherein the evaluation device ( 144 ) is configured to select at least one reflection feature of the reflection image ( 142 ), wherein the evaluation device ( 144 ) is configured for determining at least one longitudinal coordinate z of the selected reflection feature of the reflection image ( 142 ) by evaluating a combined signal Q from the sensor signals, wherein the at least one evaluation device is configured for deriving the combined signal Q by
Q ( z o )=∫∫ A 1 E ( x,y;z o ) dxdy/∫∫A 2 E ( x,y;z o )dxdy

wherein x and y are transversal coordinates, A 1 and A 2 are different areas of at least one beam profile of the reflection light beam at a position of the sensor element, and E(x,y,z 0 ) denotes the beam profile given at the object distance z o , wherein each of the sensor signals comprises at least one information of at least one area of the beam profile of the reflection light beam.

2. The detector ( 110 ) according to claim 1 , wherein the sensor element ( 114 ) is configured to determine the reflection image ( 142 ) within at least one imaging frame, wherein a duration of a single imaging frame corresponds to a pulse duration of the tunable laser source ( 126 ) of the projector ( 122 ) or a duration of a series of pulses of the tunable laser source ( 126 ) of the projector ( 122 ).

3. The detector ( 110 ) according to claim 1 , wherein the at least one property of the tunable laser source ( 126 ) is at least one property selected from the group consisting of a voltage, a current, a temperature, an emission wavelength, and an intensity.

4. The detector ( 110 ) according to claim 3 , wherein the emission wavelength of the tunable laser source ( 126 ) is adjustable by one or more of varying a driver current, changing a MEMS state, or changing the modulation of an electro-optical or acousto-optical modulator.

5. The detector ( 110 ) according to claim 1 , wherein the control unit ( 136 ) is configured to adjust the emission wavelength in steps thereby adjusting the location of the illumination patterns ( 124 ), wherein the first emission wavelength λ 1 and the second emission wavelength λ 2 are separable, wherein the first emission wavelength λ 1 and the second emission wavelength λ 2 differ by 40 nm≥|λ 1 −λ 2 |≥1 nm.

6. The detector ( 110 ) according to claim 1 , wherein the first emission wavelength λ 1 and the second emission wavelength λ 2 are stable, wherein variations in wavelength Δλ are small compared to the wavelength, wherein Δλ≤1.5%.

7. The detector ( 110 ) according to claim 1 , wherein the tunable laser source ( 126 ) is configured to generate at least one light pulse, wherein the light pulse comprises at least one beam profile, wherein the control unit ( 136 ) is configured to adjust a wavelength of the light pulse such that the wavelength within the beam profile of the light pulse varies by a wavelength variation ΔΛ by applying an electrical signal to the tunable laser source ( 126 ) and/or to adjust wavelengths of light pulses of a series of light pulses such that the wavelengths of at least two light pulses of the series of light pulses vary by the wavelength variation ΔΛ.

8. The detector ( 110 ) according to claim 1 , wherein the evaluation device ( 144 ) is configured for deriving the combined signal Q by one or more of dividing the sensor signals, dividing multiples of the sensor signals, dividing linear combinations of the sensor signals, wherein the evaluation device is configured for using at least one predetermined relationship between the combined signal Q and the longitudinal coordinate z for determining the longitudinal coordinate.

9. The detector ( 110 ) according to claim 1 , wherein the evaluation device ( 144 ) is configured to determine a longitudinal region of the selected reflection feature by evaluating the combined signal Q, wherein the longitudinal region is given by the longitudinal coordinate z and an error interval ±ε, wherein the evaluation device ( 144 ) is configured to determine at least one displacement region in at least one reference image corresponding to the longitudinal region, wherein the evaluation device ( 144 ) is configured to match the selected reflection feature with at least one reference feature within the displacement region, wherein the evaluation device ( 144 ) is configured to determine a displacement of the matched reference feature and the selected reflection feature, wherein the evaluation device ( 144 ) is configured to determine a longitudinal information of the matched reference feature using a predetermined relationship between the longitudinal information and the displacement.

10. The detector ( 110 ) according to claim 9 , wherein the reference image and the reflection image ( 142 ) are images of the object ( 112 ) determined at different spatial positions having a fixed distance, wherein the evaluation device ( 144 ) is configured to determine an epipolar line in the reference image.

11. The detector ( 110 ) according to claim 10 , wherein the displacement region extends along the epipolar line, wherein the evaluation device ( 144 ) is configured to determine the reference feature along the epipolar line corresponding to the longitudinal coordinate z and to determine an extent of the displacement region along the epipolar line corresponding to the error interval ±ε.

12. The detector ( 110 ) according to claim 11 , wherein the evaluation device ( 144 ) is configured to perform the following steps:
determining the displacemen

Assignees

• Trinamix Gmbh

Inventors

• Bonsignore Christian
• Berner Nils
• Rein Benjamin
• Send Robert

Classifications

• G01S17/89

  for mapping or imaging · CPC title

• G01S17/48

  Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves · CPC title

• G01B11/2513

  with several lines being projected in more than one direction, e.g. grids, patterns · CPC title

• H04N13/254

  in combination with electromagnetic radiation sources for illuminating objects · CPC title

• G01C3/08

  Use of electric radiation detectors · CPC title