Derivative Imaging for Subsurface Object Detection

Abstract

A series of scans is generated for a subsurface and a derivative image is created using the series of subsurface images. One or more tests are performed on the derivative image, and a subsurface object is detected based on the one or more tests. A sensor is configured to generate a series of scans for a subsurface and a processor is coupled to the sensor. The processor is configured to execute stored program instructions that cause the processor to generate a series of images of the subsurface using the series of scans, create a derivative image using the series of subsurface images, perform one or more tests on the derivative image, and detect a subsurface object based on the one or more tests.

1 . A method, comprising:
 generating a series of scans for a subsurface;   creating a derivative image using the series of subsurface images;   performing one or more tests on the derivative image; and   detecting a subsurface object based on the one or more tests.   
     
     
         2 . The method according to  claim 1 , comprising generating an output in response to detecting the subsurface obstacle. 
     
     
         3 . The method according to  claim 1 , comprising generating one or both of a visual output and an audible output in response to detecting the subsurface obstacle. 
     
     
         4 . The method according to  claim 1 , wherein creating the derivative image comprises calculating a derivative of a reflected or scattered energy parameter associated with a pixel or a pixel cluster of the subsurface images. 
     
     
         5 . The method according to  claim 1 , wherein creating the derivative image comprises:
 calculating a derivative of a parameter of the subsurface images; and   forming the derivative image using derivatives of the parameter.   
     
     
         6 . The method according to  claim 5 , wherein the parameter comprises brightness of a pixel or a pixel cluster of the subsurface images. 
     
     
         7 . The method according to  claim 1 , wherein:
 creating the derivative image comprises:
 calculating a derivative of a pixel parameter or a pixel cluster parameter of the subsurface images; and 
 forming the derivative image using derivatives of the pixel or pixel cluster parameter; and 
   performing one or more tests on the derivative image comprises:
 determining whether a derivative of each pixel or pixel cluster exceeds a first threshold; and 
 determining whether the previous n derivatives for this pixel or pixel cluster exceeds a second threshold, wherein n is an integer. 
   
     
     
         8 . The method according to  claim 7 , wherein one or both of the first threshold and the second threshold are adjustable. 
     
     
         9 . The method according to  claim 1 , wherein:
 creating the derivative image comprises:
 calculating a derivative of a pixel parameter or a pixel cluster parameter of the subsurface images; and 
 forming the derivative image using derivatives of the pixel or pixel cluster parameter; and 
   performing one or more tests on the derivative image comprises performing at least two of:
 determining whether the derivative of each pixel or pixel cluster exceeds a first threshold; 
 determining whether the previous n derivatives for this pixel or pixel cluster exceeds a second threshold, wherein n is an integer; 
 determining if a range associated with each pixel or pixel cluster is less than a predetermined detection range; and 
 determining if a location associated with each pixel or pixel cluster is beyond a predetermined position. 
   
     
     
         10 . The method according to  claim 1 , comprising:
 forming a mask image comprising one or more markers indicative of object detection location;   applying the mask image to the subsurface images; and   displaying the mask image applied to the subsurface images.   
     
     
         11 . The method according to  claim 1 , comprising cropping the subsurface images to excise portions of the subsurface images beyond a predetermined detection range. 
     
     
         12 . The method according to  claim 1 , wherein:
 generating the subsurface images comprises creating a synthetic aperture radar (SAR) image using the series of scans; and   creating the derivative image comprises creating a derivative image of the SAR image.   
     
     
         13 . A system, comprising:
 a sensor configured to generate a series of scans for a subsurface; and   a processor coupled to the sensor and configured to execute stored program instructions that cause the processor to generate a series of images of the subsurface using the series of scans, create a derivative image using the series of subsurface images, perform one or more tests on the derivative image, and detect a subsurface object based on the one or more tests.   
     
     
         14 . The system according to  claim 13 , wherein the sensor comprises a ground penetrating radar. 
     
     
         15 . The system according to  claim 13 , wherein the sensor comprises an acoustic or a seismic sensor. 
     
     
         16 . The system according to  claim 13 , wherein the sensor comprises an electromagnetic sensor. 
     
     
         17 . The system according to  claim 13 , wherein the sensor comprises at least one of:
 a magnetic field generator and a detector configured to detect a return signal;   a magnetic resonance (MRI) source and a detector configured to detect a return signal;   a positron emission (PET) source and a detector configured to detect a return signal;   a nuclear magnetic resonance (NMR) sensor and a detector configured to detect a return signal; and   a time-domain electromagnetic (TDEM) sensor and a detector configured to detect a return signal.   
     
     
         18 . The system according to  claim 13 , wherein the sensor comprises a housing configured for above-ground portability. 
     
     
         19 . The system according to  claim 13 , wherein the sensor comprises a housing configured for subsurface deployment. 
     
     
         20 . The system according to  claim 13 , comprising a user interface coupled to the processor, the user interface comprising a display for displaying subsurface images and indicia indicative of the detected subsurface object. 
     
     
         21 - 27 . (canceled)