Method and device for suppressing electromagnetic background radiation in an image

• US 7,809,182 B2
• Filed: 06/07/2002
• Issued: 10/05/2010
• Est. Priority Date: 07/06/2001
• Status: Active Grant

• Current Assignee: Leica Geosystems AG (Hexagon AB)
• Original Assignee: Leica Geosystems AG (Hexagon AB)
• Inventors: Kirschner, Holger
• Primary Examiner(s): Chen; Wenpeng
• Assistant Examiner(s): Thirugnanam; Gandhi
• Application Number:
  US10/482,279
• Publication Number:
  US 20040208340A1
• Time in Patent Office: 3,042 Days
• Field of Search: 382/291, 382/287, 382/154, 382/106, 382/284, 331/54, 331/06, 332/84
• US Class Current: 382/154
• CPC Class Codes: F41G 3/145 using a target illuminator
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection

Abstract

A method for suppressing electromagnetic background radiation in the image according to a precharacterization, a device for carrying out the method according to a precharacterization, a measuring instrument, and a use of the device for identifying a laser signal as a mark for subsequent measuring processes as well as for identifying a source of a laser signal.

Claims

1. A method for suppressing electromagnetic background radiation in a defined spectral range relative to a signal to be detected, comprising:

recording electromagnetic radiation of;

at least one uni-dimensional or multidimensional P-image in the defined spectral range (P), and

at least one uni-dimensional or multidimensional N-image in at least one further defined spectral range differing from that of the at least one uni-dimensional or multidimensional P-image; and

performing signal and information processing on the at least one uni-dimensional or multidimensional P-image and on the at least one uni-dimensional or multidimensional N-image,

wherein an image brightness S_sp of the background radiation in the P-image is deduced on the basis of a physical model of the spectral distribution of the background radiation or a spectral curve which is directly measured,

the signal to be detected is extracted based on the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image,

the spectral ranges of the at least one uni-dimensional or multidimensional P-image and of the at least one uni-dimensional or multidimensional N-image are determined as a two-band neighbourhood method by a choice of a wavelength band in each case for the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image,

the wavelength band of the at least one uni-dimensional or multidimensional N-image is either on a short-wave or on a long wave side of the wavelength band of the at least one uni-dimensional or multidimensional P image,

wherein the number of dimensions of the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image are the same.

3. The method according to claim 1,

wherein the spectral range of the at least one uni-dimensional or multidimensional N-image is determined by the choice of two wavelength bands, and

the two wavelength bands of the at least one uni-dimensional or multidimensional N-image are on the short wave or long wave side of the wavelength band of the at least one uni-dimensional or multidimensional P-image.

4. The method according to claim 1 further comprising,

deriving the image brightness S_sp of the background radiation by carrying out the steps of the method of claim 1 several times for multiple spectral ranges for estimating and eliminating contributions of different interfering radiation sources,

wherein the image brightness S_sp of the background radiation is derived.

5. The method according to claim 1,

wherein the deduction of the image brightness S_sp of the background radiation in the at least one uni-dimensional or multidimensional P-image is carried out using at least one of the following methods:

extrapolation of at least one image brightness S_SN recorded in the at least one uni-dimensional or multidimensional N-image, and

calculation of a weighted mean value of at least two image brightnesses S_SNi recorded in the at least one uni-dimensional or multidimensional N-image.

2. A method for suppressing electromagnetic background radiation in a defined spectral range relative to a signal to be detected, comprising:

recording electromagnetic radiation of

at least one uni-dimensional or multidimensional P-image in the defined spectral range, and

at least one uni-dimensional or multi-dimensional N-image in at least one further defined spectral range differing from that of the at least one uni-dimensional or multidimensional P-image being recorded during the recording electromagnetic radiation,

performing signal and information processing on the at least one uni-dimensional or multidimensional P-image and on the at least one uni-dimensional or multidimensional N-image,

wherein an image brightness S_sp of the background radiation in the at least one uni-dimensional or multidimensional P-image is deduced on the basis of a physical model of the spectral distribution of the background radiation or a spectral curve which is directly measured,

the signal to be detected is extracted based on the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image,

the spectral ranges of the at least one uni-dimensional or multidimensional P-image and of the at least one uni-dimensional or multidimensional N-image are determined by a choice of at least one wavelength band in each case for the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image,

the wavelength bands each sense different lines,

wherein the number of dimensions of the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image are the same.

6. A device for suppressing electromagnetic background radiation in a defined spectral range relative to a signal to be detected, comprising means for recording electromagnetic radiation, comprising:

means for recording electromagnetic radiation,

the means for recording electromagnetic radiation being designed for recording of at least one uni-dimensional or multidimensional P-image and at least one uni-dimensional or multidimensional N-image; and

means for signal and information processing, the means for signal and information processing being designed so that electromagnetic background radiation can be suppressed from the different content of the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image adjusted by the means for signal and information processing,

wherein the means for recording electromagnetic radiation have at least two detectors for recording images in at least two different, defined spectral ranges,

the means for signal and information processing are designed so that the electromagnetic background radiation can be suppressed on the basis of a physical model of the spectral distribution of the background radiation or a spectral curve which is directly measured,

wherein the number of dimensions of the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image are the same.

7. The device according to claim 6,

wherein the spectral range of the means for recording electromagnetic radiation is limited by a spectral filter or the means for recording electromagnetic radiation has at least one detector which comprises two or more semiconductor materials which result in a spectrally selective response behaviour of the detector.

8. The device according to claim 6,

wherein the means for signal and information processing is designed so that the at least one uni-dimensional or multidimensional P-image and the at least one uni-dimensional or multidimensional N-image are translatable or rotatable relative to one another and can be changed on a relative imaging scale.

9. The device according to claim 6, further comprising a measuring instrument,

wherein the measuring instrument has a device for spectrally selective suppression of an electromagnetic background radiation to be detected.

10. A method for identifying a laser spot as a mark for subsequent measuring processes using a device according to claim 6.

11. A method for identifying a source of a laser spot using a device according to claim 6.