# US 11,079,491 B1 · Detecting objects in obscured environments via speckle correlation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,491 B1 - Document ID: US11079491B1 - Status: Granted - Kind: B1 - Application number: 16/102,355 - Filed: 2018-08-13 - Granted: 2021-08-03 - Earliest claimed: 2018-08-13 - Assignees: Northrop Grumman Systems Corporation - Applicants: Alan Heins - Inventors: Alan Heins - Web page: https://patentgrep.com/patent/US11079491B1 ## CPC - G01S 17/04: Systems determining the presence of a target - G01S 7/4816: {of receivers alone} - G01S 17/89: for mapping or imaging - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract Systems and methods are provided for provided for determining the presence of an object within a region of interest. A broadband laser is projected at a selected location in the region of interest. Reflected light from the selected location in the region of interest is received at a receiver. The received light is dispersed by wavelength across a first axis at a dispersive element. The received light is dispersed by return angle across a second axis at a defocuser. The received light is imaged to provide an image, and a metric representing a correlation between the wavelength and the return angle is measured in the image to determine the presence of the object. ## Claims ### Claim 1 A method for determining the presence of an object within a region of interest, comprising: projecting a broadband laser at a selected location in the region of interest; receiving reflected light from the selected location in the region of interest at a receiver; dispersing the received light by wavelength across a first axis at a dispersive element; dispersing the received light by return angle across a second axis at a defocuser; imaging the received light to provide an image; measuring a metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object; and alerting an operator if it is determined that the object is present in the region of interest. ### Claim 2 (depends on 1) The method of claim 1, wherein the metric is a first metric, the image is a first image, and the method further comprises: selecting a new location in the region of interest; projecting the broadband laser at the new location; receiving reflected light from the new location in the region of interest at the receiver; dispersing the received light from the new location by wavelength across the first axis at the dispersive element; dispersing the received light from the new location by return angle across the second axis at the defocuser; imaging the received light from the new location to provide a second image; and measuring a second metric representing a correlation between the wavelength and the return angle in the second image to determine the presence of the object. ### Claim 3 (depends on 1) The method of claim 1, wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object comprises determining a coefficient of multiple correlation of the return angle and the wavelength on an intensity of the reflected light in the image. ### Claim 4 (depends on 1) The method of claim 1, wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object comprises determining a correlation length between the return angle and the wavelength in the image. ### Claim 5 (depends on 4) The method of claim 4, wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object further comprises determining that the object is present if the correlation length exceeds a first threshold value and determining that the object is a man-made object if the correlation length exceeds a second threshold value. ### Claim 6 A system for determining the presence of an object within a region of interest, comprising: a broadband laser that projects light at a selected location in the region of interest; a receiver that receives reflected light from the selected location in the region of interest, the receiver comprising: a dispersive element that disperses the received light by wavelength across a first axis; a defocuser that disperses the received light by return angle across a second axis; an imager that images the received light to provide an image; and an image analysis component that measures a metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object, the image analysis component determining that an object is present if the metric exceeds a threshold value. ### Claim 7 (depends on 6) The system of claim 6, wherein the broadband laser projects the light in a wavelength band within the infrared band. ### Claim 8 (depends on 6) The system of claim 6, wherein the dispersive element is implemented as a dispersive prism. ### Claim 9 (depends on 6) The system of claim 6, wherein the dispersive element is implemented as a diffraction grating. ### Claim 10 (depends on 6) The system of claim 6, wherein the defocuser is implemented as a cylindrical lens. ### Claim 11 (depends on 6) The system of claim 6, further comprising a user interface that alerts an operator of the presence of the object if the image analysis component determines that the object is present. ### Claim 12 (depends on 6) The system of claim 6, wherein the image analysis component determines a coefficient of multiple correlation of the return angle and the wavelength in the image. ### Claim 13 (depends on 6) The system of claim 6, wherein the threshold value is a first threshold value and the image analysis component determines that the object is a man-made object if the metric exceeds a second threshold value. ### Claim 14 (depends on 6) The system of claim 6, wherein the image analysis component determines a correlation length between the return angle and the wavelength in the image. ### Claim 15 A method for determining the presence of an object within a region of interest, comprising: projecting a broadband laser at a selected location in the region of interest; receiving reflected light from the selected location in the region of interest at a receiver; dispersing the received light by wavelength across a first axis at a dispersive element; dispersing the received light by return angle across a second axis at a defocuser; imaging the received light to provide an image; and measuring a metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object; wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object comprises determining a coefficient of multiple correlation of the return angle and the wavelength on an intensity of the reflected light in the image. ### Claim 16 (depends on 15) The method of claim 15, wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object further comprises determining that the object is present if the coefficient of multiple correlation exceeds a threshold value. ### Claim 17 A method for determining the presence of an object within a region of interest, comprising: projecting a broadband laser at a selected location in the region of interest; receiving reflected light from the selected location in the region of interest at a receiver; dispersing the received light by wavelength across a first axis at a dispersive element; dispersing the received light by return angle across a second axis at a defocuser; imaging the received light to provide an image; and measuring a metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object; wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object comprises determining a correlation length between the return angle and the wavelength in the image. ### Claim 18 (depends on 17) The method of claim 17, wherein measuring the metric representing a correlation between the wavelength and the return angle in the image to determine the presence of the object further comprises determining that the object is present if the correlation length exceeds a first threshold value and determining that the object is a man-made object if the correlation length exceeds a second threshold value. ### Claim 19 (depends on 17) The method of claim 17, wherein measuring the metric representing a correlation between the wavelength and the return angle in the image comprises determining one of the Moran I or Geary's C. ### Claim 20 A method for determining the presence of an object within a region of interest, comprising: projecting a broadband laser at a selected location in the region of interest; receiving reflected light from the selected location in the region of interest at a receiver; dispersing the received light by wavelength across a first axis at a dispersive element; dispersing the received light by return angle across a second axis at a defocuser; imaging the received light to provide a first image; measuring a first metric representing a correlation between the wavelength and the return angle in the first image to determine the presence of the object; selecting a new location in the region of interest; projecting the broadband laser at the new location; receiving reflected light from the new location in the region of interest at the receiver; dispersing the received light from the new location by wavelength across the first axis at the dispersive element; dispersing the received light from the new location by return angle across the second axis at the defocuser; imaging the received light from the new location to provide a second image; and measuring a second metric representing a correlation between the wavelength and the return angle in the second image to determine the presence of the object.