Patent Publication Number: US-11385105-B2

Title: Techniques for determining emitted radiation intensity

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of U.S. Provisional Patent Application No. 62/318,099 filed on Apr. 4, 2016 which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to thermal image processing and, more particularly, to determining emitted radiation intensity of objects in thermal images. 
     BACKGROUND 
     In the field of thermal imaging, there is often a difference between the actual emitted radiation intensity of an object and the measured radiation intensity received by a thermal imager. This difference is typically caused by attenuation of the emitted radiation over distance. Various techniques have been developed to compensate for such attenuation, but with limited success. 
     In some cases, the distance between the thermal imager and the imaged object may be measured directly using, for example, a laser or radar device. Unfortunately, such distance measurement techniques typically require additional equipment and may be cumbersome to implement. In other cases, the thermal imager may be configured to assume a preset distance (e.g., approximately three meters) and compensate based on that distance. However, such present techniques have limited applicability and may still provide inaccurate information for objects at distances greater or lesser than the preset distance. Moreover, such techniques may not be suited for objects that are moving either toward or away from the imaging camera, and may only be applicable to motionless scenes. 
     SUMMARY 
     Systems and methods are disclosed herein in accordance with one or more embodiments that provide an improved approach to compensate for a reduction in measured radiation intensity of a thermal image caused by radiation attenuation over a distance from an image capture component to the object being imaged. 
     In one embodiment, a method includes capturing a thermal image of a scene by an image capture component; selecting a pixel of the thermal image, wherein the pixel has a value corresponding to a measured radiation intensity associated with an object in the scene; determining real world coordinates of the object; and calculating an emitted radiation intensity of the object using the determined real world coordinates and the measured radiation intensity. 
     In another embodiment, a system includes a memory component configured to store a plurality of captured thermal images of a scene by an image capture component; a processor configured to: select a pixel of the thermal image, wherein the pixel has a value corresponding to a measured radiation intensity associated with an object in the scene; determine real world coordinates of the object; and calculate an emitted radiation intensity of the object using the determined real world coordinates and the measured radiation intensity. 
     The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a block diagram of an imaging system in accordance with an embodiment of the disclosure. 
         FIG. 2  illustrates a block diagram of an image capture component in accordance with an embodiment of the disclosure. 
         FIG. 3  illustrates a plot of measured radiation intensity of several moving objects in accordance with an embodiment of the disclosure. 
         FIG. 4  illustrates a diagram showing relationships between several measured radiation intensity values of  FIG. 3  and real world locations in accordance with an embodiment of the disclosure. 
         FIGS. 5 and 6  illustrate locations of pixels on an image plane corresponding to the measured radiation intensity values of  FIG. 4  in accordance with embodiments of the disclosure. 
         FIGS. 7A and 7B  illustrate examples of using vanishing points to determine camera parameters in accordance with embodiments of the disclosure. 
         FIG. 8  illustrates a process of determining emitted radiation intensity of a moving object in accordance with an embodiment of the disclosure. 
         FIG. 9  illustrates a process of determining real world coordinates of a moving object using camera calibration parameters in accordance with an embodiment of the disclosure. 
         FIG. 10  illustrates a process of determining real world coordinates of a moving object using measured radiation intensity values in accordance with an embodiment of the disclosure. 
     
    
    
     Embodiments of the present invention and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. 
     DETAILED DESCRIPTION 
     Techniques are provided to compensate for reductions in measured radiation intensities on captured thermal images. An emitted radiation intensity of an object may be attenuated on a captured thermal image by, for example, atmospheric absorption of radiation intensity. Measured radiation intensity of the object may thus be reduced as a function of the distance between the image capture component and the object being imaged. In this regard, the measured radiation intensity of an object on a captured thermal image may vary as the object travels either toward or away from the image capture component. 
     In various embodiments, one or more thermal images of an object may be captured by an image capture component. A pixel location of the object may be identified on an image plane of the captured image. Real world coordinates of the object may be determined from the pixel location on the image plane. A distance from the image capture component to the object may be determined using the determined real world coordinates. An emitted radiation intensity of the object may be determined using the measured radiation intensity and the distance. 
     In some embodiments, real world coordinates of the object may be determined using camera parameters to translate the pixel location of the object on an image plane to real world coordinates. In some embodiments, real world coordinates may be determined using the measured radiation intensity value, and an angle defined by the image capture component and the selected pixel locations on the image plane. 
     In various embodiments, the processing techniques described herein may be advantageously used to compensate for a reduction in measured radiation intensity at distances greater than attenuation compensation capabilities of conventional imaging cameras. For example, in various embodiments disclosed herein, additional equipment is not required to determine a distance of an object beyond the capability of a conventional imaging camera. Additionally, manual entry of camera parameters is not required, reducing the possibility of human error. Utilizing pixel information inherent in a thermal image and camera parameters easily accessed from the imaging camera provides for effective and robust thermal radiation distance attenuation compensation. 
       FIG. 1  illustrates a block diagram of an imaging system  100  in accordance with an embodiment of the disclosure. Imaging system  100  may be used to capture and process image frames in accordance with various techniques described herein. In one embodiment, various components of imaging system  100  may be provided in a camera component  101 , such as an imaging camera. In another embodiment, one or more components of imaging system  100  may be implemented remotely from each other in a distributed fashion (e.g., networked or otherwise). 
     In various embodiments, imaging system  100  provides a capability to determine real world coordinates of a selected object within a scene  170 . For example, imaging system  100  may be configured to capture one or more images of scene  170  using camera component  101  (e.g., a thermal imaging camera). Captured images may be received by a processing component  110  and stored in a memory component  120 . Processing component  110  may be configured to select a pixel associated with the object within an array of unit cells (e.g., such as unit cell array  232  of  FIG. 2 ) of an image capture component  130 . Processing component  110  may be configured to determine a measured radiation intensity value of the pixel associated with the object. Processing component  110  may determine real world coordinates of the object from the location of the pixel on an image plane. Processing component  110  may be configured to determine imaging system  100  parameters such as focal length of image capture component  130 , size of image capture component  130  unit cells (e.g., unit cells  232  of  FIG. 2 ), and resolution of image capture component  130 . 
     In one embodiment, imaging system  100  includes processing component  110 , a memory component  120 , image capture component  130 , optical components  132  (e.g., one or more lenses configured to receive electromagnetic radiation through an aperture  134  in camera component  101  and pass the electromagnetic radiation to image capture component  130 ), an image capture interface component  136 , a display component  140 , a control component  150 , a communication component  152 , and other sensing components  160 . 
     In various embodiments, imaging system  100  may be implemented as an imaging camera, such as camera component  101 , to capture image frames, for example, of scene  170  (e.g., a field of view). In some embodiments, camera component  101  may include image capture component  130 , optical components  132 , and image capture interface component  136  housed in a protective enclosure. Imaging system  100  may represent any type of camera system which, for example, detects electromagnetic radiation (e.g., thermal radiation) and provides representative data (e.g., one or more still image frames or video image frames). For example, imaging system  100  may represent a camera component  101  that is directed to detect visible light and/or infrared radiation and provide associated image data. 
     Imaging system  100  may include a portable device and may be implemented, for example, coupled to various types of vehicles (e.g., an automobile, a truck, or other land-based vehicles). Imaging system  100  may be implemented with camera component  101  at various types of fixed scenes (e.g., automobile roadway, train railway, or other scenes) via one or more types of structural mounts. In some embodiments, camera component  101  may be mounted in a stationary arrangement to capture repetitive thermal images of scene  170 . 
     Processing component  110  may include, for example, a microprocessor, a single-core processor, a multi-core processor, a microcontroller, a logic device (e.g., a programmable logic device configured to perform processing operations), a digital signal processing (DSP) device, one or more memories for storing executable instructions (e.g., software, firmware, or other instructions), and/or any other appropriate combinations of processing device and/or memory to execute instructions to perform any of the various operations described herein. Processing component  110  is adapted to interface and communicate with components  120 ,  130 ,  140 ,  150 , and  160  to perform method and processing steps as described herein. In various embodiments, it should be appreciated that processing operations and/or instructions may be integrated in software and/or hardware as part of processing component  110 , or code (e.g., software or configuration data) which may be stored in memory component  120 . Embodiments of processing operations and/or instructions disclosed herein may be stored by a machine readable medium  113  in a non-transitory manner (e.g., a memory, a hard drive, a compact disk, a digital video disk, or a flash memory) to be executed by a computer (e.g., logic or processor-based system) to perform various methods disclosed herein. 
     In various embodiments, the machine readable medium  113  may be included as part of imaging system  100  and/or separate from imaging system  100 , with stored instructions provided to imaging system  100  by coupling the machine readable medium  113  to imaging system  100  and/or by imaging system  100  downloading (e.g., via a wired or wireless link) the instructions from the machine readable medium (e.g., containing the non-transitory information). In various embodiments, as described herein, instructions provide for real time applications of processing various image frames of scene  170 . 
     Memory component  120  includes, in one embodiment, one or more memory devices (e.g., one or more memories) to store data and information. The one or more memory devices may include various types of memory including volatile and non-volatile memory devices, such as RAM (Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically-Erasable Read-Only Memory), flash memory, or other types of memory. In one embodiment, processing component  110  is adapted to execute software stored in memory component  120  and/or machine readable medium  113  to perform various methods, processes, and operations in a manner as described herein. 
     Image capture component  130  includes, in one embodiment, one or more sensors (e.g., any type visible light, infrared, or other type of detector) for capturing image signals representative of an image of scene  170 . In one embodiment, the sensors of image capture component  130  provide for representing (e.g., converting) a captured thermal image signal of scene  170  as digital data (e.g., via an analog-to-digital converter included as part of the sensor or separate from the sensor as part of imaging system  100 ). 
     Processing component  110  may be adapted to receive image signals from image capture component  130 , process image signals (e.g., to provide processed image data), store image signals or image data in memory component  120 , and/or retrieve stored image signals from memory component  120 . In various aspects, processing component  110  may be remotely positioned, and processing component  110  may be adapted to remotely receive image signals from image capture component  130  via wired or wireless communication with image capture interface component  136 , as described herein. Processing component  110  may be adapted to process image signals stored in memory component  120  to provide image data (e.g., captured and/or processed image data) to display component  140  for viewing by a user. 
     Display component  140  includes, in one embodiment, an image display device (e.g., a liquid crystal display (LCD)) or various other types of generally known video displays or monitors. Processing component  110  may be adapted to display image data and information on display component  140 . Processing component  110  may be adapted to retrieve image data and information from memory component  120  and display any retrieved image data and information on display component  140 . Display component  140  may include display electronics, which may be utilized by processing component  110  to display image data and information. Display component  140  may receive image data and information directly from image capture component  130  via processing component  110 , or the image data and information may be transferred from memory component  120  via processing component  110 . 
     Control component  150  includes, in one embodiment, a user input and/or interface device having one or more user actuated components, such as one or more push buttons, slide bars, rotatable knobs or a keyboard, that are adapted to generate one or more user actuated input control signals. Control component  150  may be adapted to be integrated as part of display component  140  to operate as both a user input device and a display device, such as, for example, a touch screen device adapted to receive input signals from a user touching different parts of the display screen. Processing component  110  may be adapted to sense control input signals from control component  150  and respond to any sensed control input signals received therefrom. 
     Control component  150  may include, in one embodiment, a control panel unit (e.g., a wired or wireless handheld control unit) having one or more user-activated mechanisms (e.g., buttons, knobs, sliders, or others) adapted to interface with a user and receive user input control signals. In various embodiments, it should be appreciated that the control panel unit may be adapted to include one or more other user-activated mechanisms to provide various other control operations of imaging system  100 , such as auto-focus, menu enable and selection, field of view (FoV), brightness, contrast, gain, offset, spatial, temporal, and/or various other features and/or parameters. 
     In another embodiment, control component  150  may include a graphical user interface (GUI), which may be integrated as part of display component  140  (e.g., a user actuated touch screen), having one or more images of the user-activated mechanisms (e.g., buttons, knobs, sliders, or others), which are adapted to interface with a user and receive user input control signals via the display component  140 . As an example for one or more embodiments as discussed further herein, display component  140  and control component  150  may represent appropriate portions of a tablet, a laptop computer, a desktop computer, or other type of device. 
     Processing component  110  may be adapted to communicate with image capture interface component  136  (e.g., by receiving data and information from image capture component  130 ). Image capture interface component  136  may be configured to receive image signals (e.g., image frames) from image capture component  130  and communicate image signals to processing component  110  directly or through one or more wired or wireless communication components (e.g., represented by connection  137 ) in the manner of communication component  152  further described herein. Camera component  101  and processing component  110  may be positioned proximate to or remote from each other in various embodiments. 
     In another embodiment, imaging system  100  may include one or more other types of sensing components  160 , including environmental and/or operational sensors, depending on the sensed application or implementation, which provide information to processing component  110  (e.g., by receiving sensor information from each sensing component  160 ). In various embodiments, other sensing components  160  may be adapted to provide data and information related to environmental conditions, such as internal and/or external temperature conditions, lighting conditions (e.g., day, night, dusk, and/or dawn), humidity levels, specific weather conditions (e.g., sun, rain, and/or snow), distance (e.g., laser rangefinder), and/or whether a tunnel, a covered parking garage, or that some type of enclosure has been entered or exited. Accordingly, other sensing components  160  may include one or more conventional sensors as would be known by those skilled in the art for monitoring various conditions (e.g., environmental conditions) that may have an effect (e.g., on the image appearance) on the data provided by image capture component  130 . 
     In some embodiments, other sensing components  160  may include devices that relay information to processing component  110  via wireless communication. For example, each sensing component  160  may be adapted to receive information from a satellite, through a local broadcast (e.g., radio frequency) transmission, through a mobile or cellular network and/or through information beacons in an infrastructure (e.g., a transportation or highway information beacon infrastructure) or various other wired or wireless techniques. 
     In one embodiment, communication component  152  may be implemented as a network interface component (NIC) adapted for communication with a network including other devices in the network. In various embodiments, communication component  152  may include one or more wired or wireless communication components, such as an Ethernet connection, a wireless local area network (WLAN) component based on the IEEE 802.11 standards, a wireless broadband component, mobile cellular component, a wireless satellite component, or various other types of wireless communication components including radio frequency (RF), microwave frequency (MWF), and/or infrared frequency (IRF) components adapted for communication with a network. As such, communication component  152  may include an antenna coupled thereto for wireless communication purposes. In other embodiments, the communication component  152  may be adapted to interface with a DSL (e.g., Digital Subscriber Line) modem, a PSTN (Public Switched Telephone Network) modem, an Ethernet device, and/or various other types of wired and/or wireless network communication devices adapted for communication with a network. 
     In various embodiments, a network may be implemented as a single network or a combination of multiple networks. For example, in various embodiments, the network may include the Internet and/or one or more intranets, landline networks, wireless networks, and/or other appropriate types of communication networks. In another example, the network may include a wireless telecommunications network (e.g., cellular phone network) adapted to communicate with other communication networks, such as the Internet. As such, in various embodiments, imaging system  100  and/or its individual associated components may be associated with a particular network link such as for example a URL (Uniform Resource Locator), an IP (Internet Protocol) address, and/or a mobile phone number. 
       FIG. 2  illustrates a block diagram of an image capture component  130  in accordance with an embodiment of the disclosure. In this illustrated embodiment, image capture component  130  is a focal plane array (FPA) including an array of unit cells  232  and a read out integrated circuit (ROIC)  202 . Each unit cell  232  may be provided with an infrared detector (e.g., a microbolometer or other appropriate sensor) and associated circuitry to provide image data for a pixel of a captured thermal image frame. In this regard, time-multiplexed electrical signals may be provided by the unit cells  232  to ROIC  202 . 
     ROIC  202  includes bias generation and timing control circuitry  204 , column amplifiers  205 , a column multiplexer  206 , a row multiplexer  208 , and an output amplifier  210 . Image frames captured by infrared sensors of the unit cells  232  may be provided by output amplifier  210  to processing component  110  and/or any other appropriate components to perform various processing techniques described herein. Although an 8 by 8 array is shown in  FIG. 2 , any desired array configuration may be used in other embodiments. Further descriptions of ROICs and infrared sensors (e.g., microbolometer circuits) may be found in U.S. Pat. No. 6,028,309 issued Feb. 22, 2000, which is incorporated herein by reference in its entirety. 
       FIG. 3  illustrates a plot  300  of measured radiation intensity of several moving objects in accordance with an embodiment of the disclosure. In particular, plot  300  includes three time periods,  310 ,  320 , and  330 , where each time period is associated with a different moving object, such as a moving vehicle travelling through a scene  170  of a roadway. In this illustration, camera component  101  of imaging system  100  may be mounted to a stationary fixture along the roadway within scene  170 . Camera component  101  may capture successive thermal images of scene  170  using image capture component  130 . Processing component  110  may process the successive thermal images and select a pixel from each captured thermal image having the highest measured radiation intensity associated with the moving vehicle. Furthermore, the selected pixel within the thermal image may be different (e.g., such as a different location on the thermal image and/or a different intensity value) for each captured thermal image. Thus, each time period  310 ,  320 , and  330  includes a plot of pixel values corresponding to the highest measured radiation intensity for the various thermal images captured over the corresponding time period. 
     As discussed, plot  300  is associated with several moving vehicles, each of which provides a source of emitted radiation. In this regard, each vehicle is associated with a respective time period  310 ,  320 , or  330  and provides a source of emitted radiation intensity that is substantially constant over the respective time period, such as an exhaust pipe emitting substantially constant thermal radiation. Plot  300  shows that individual plots of selected pixel values within each time period have similar curvature features. Generally, for each time period  310 ,  320 , and  330 , measured radiation intensity values are highest, as shown on plot  300  of  FIG. 3  from point  311  to  312 ,  321  to  322 , and  331  to  332 , when the respective moving vehicle is closest to camera component  101 . Furthermore, each of the measured radiation intensities decrease as the vehicle travels away from camera component  101 , as shown on plot  300  from point  312  to the end of time period  310 , point  322  to the end of time period  320 , and point  332  to the end of time period  330 . 
     Plots  310 ,  320 , and  330  each show that measured radiation intensity captured on a thermal image changes in intensity magnitude as the substantially constant emitted radiation source travels away from and/or toward an image capture component  130 . Thus, there is a desire to compensate the measured radiation intensity on a thermal image due to attenuation of the emitted radiation intensity as an object travels a distance from camera component  101 . 
     Referring again to  FIG. 3 , time period  320  includes a measured radiation intensity value corresponding to a pixel i 1  selected from a thermal image captured at time  305  (e.g., T 1 ). Plot  320  also includes a measured radiation intensity value corresponding to a pixel i 2  selected from a thermal image captured at time  307  (e.g., T 2 ). Pixel i 1  and pixel i 2  may be at different locations on their respective thermal images (e.g., as shown by locations  404   a  and  406   a  on an image plane  402  of  FIG. 4 ). Pixel it and/or pixel i 2  projected onto an image plane may be used in determination of real world coordinates associated with an object (e.g., such as the source of emitted radiation intensity of moving vehicles of plot  300 ), as described herein. Furthermore, measured radiation intensity values of pixels i 1  and/or i 2  may be used in determining the emitted radiation intensity of the object to aid in compensating for distance attenuation of thermal radiation, as described herein. 
       FIG. 4  illustrates a diagram showing relationships between several measured radiation intensity values of  FIG. 3  and real world locations in accordance with an embodiment of the disclosure. As shown in  FIG. 4 , pixels i 1  and pixel i 2  on image plane  402  correspond to real world points  404   b  (e.g., P 1 ) and  406   b  (e.g., P 2 ), respectively.  FIG. 4  shows an image plane coordinate system  408  (e.g., u,v), a camera coordinate system  412  (e.g., x′, y′, z′), and a real world coordinate system  424  (e.g., X, Y, Z). Processes and methods described herein may be used to make a translation from locations  404   a  and  406   a  of image plane coordinate system  408  to locations  404   b  and  406   b  of real world coordinate system  424 . Processing component  110  may determine real world coordinates for points  404   b  (P 1 ) and  406   b  (P 2 ) from image plane  402  locations  404   a  of pixel i 1  and  406   a  of pixel i 2 . The real world coordinates for points  404   b  and/or  406   b  may be used to determine the emitted radiation intensity at the thermal radiation source of the object corresponding to points  404   b  and/or  406   b.    
     In one embodiment, an emitted radiation intensity of a thermal radiation source may be determined using equation 1A. Equation 1A provides that the measured radiation intensity (I) is inversely proportional to the square of a distance (D) to the emitted radiation intensity (R) of a radiation source. 
                   I   =     R     4   ⁢   π   *     D   2                 (     equation   ⁢           ⁢   1   ⁢   A     )               
For example, in equation 1A, I may be the measured radiation intensity of pixels i 1  and/or i 2 , and R may be the emitted radiation intensity of the radiation source (e.g., one of the moving vehicles of  FIG. 3 ).
 
     Although equation 1A will be further discussed herein, the inverse square relationship between measured radiation intensity I distance D identified in equation 1A is particularly suited for lens-less systems wherein there are no lenses (e.g., optical elements) or other atmospheric factors intervening between image plane  402  and points  404   b  and  404   b  discussed herein. 
     In other embodiments where the effects of atmospheric factors are present, the following equation 1B may be used:
 
 I=R*e   α * D    (equation 1B)
 
For example, in equation 1B, α may be an extinction coefficient associated with attenuation due to atmospheric factors (e.g., temperature, humidity, particulate, and/or other factors). Where appropriate, additional adjustments may be made to further account for changes in intensity associated with one or more optical elements disposed in front of image plane  402  (e.g., whether factored into extinction coefficient α or otherwise).
 
     In some embodiments, processing component  110  may calculate extinction coefficient α based on, for example, temperature measurements, humidity measurements, and/or other measurements received from one or more sensing components  160 . In some embodiments, such measurements may be provided by remote systems (e.g., networked or otherwise) to imaging system  100  (e.g., where imaging system  100  is implemented as part of a networked traffic camera system). 
     Referring again to equation 1A, by substituting the measured radiation intensity value of pixel i 1  and the measured radiation intensity value of pixel i 2  for I, and the distance  414  from point (P 1 )  404   b  to a camera origin (O)  410  (e.g., D(P 1 , O)) and the distance  416  from point (P 2 )  406   b  to camera origin (O)  410  (e.g., D(P 2 , O)) for D, equation 1A may be re-written in the form of equations 2 and 3. 
     
       
         
           
             
               
                 
                   
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     Equations 2 and 3 may be re-ordered into the form of equation 4 by assuming the emitted radiation intensity (R) of the moving object remains substantially constant. Furthermore, the term 4π is a constant value and may be ignored for this re-ordering.
 
 i 1( D ( P 1,  O )) 2   =i 2( D ( P 2,  O )) 2    (equation 4)
 
     Rearranging equation 4 forms the following equation 5. 
     
       
         
           
             
               
                 
                   
                     
                       
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     Referring to  FIG. 4  and applying the sine rule of triangles provides, length  416  (e.g., D(P 2 , O)) divided by sine of angle  415  (Y) is equal to length  414  (e.g., D(P 1 , O)) divided by sine of angle  417  (B). Equation 5 may be rewritten in the form of equation 6 using substitution based on the sine rule. 
     
       
         
           
             
               
                 
                   
                     
                       
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     Equation 6 may be rewritten in the form of equation 7 by substituting angle (Y) with (180-a-B) (e.g., using the principle that the sum of angles of a triangle equals one hundred-eighty degrees). 
     
       
         
           
             
               
                 
                   
                     
                       
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     Referring to  FIG. 4 , angle (a)  418  may be calculated using camera parameter focal length (f)  419 , length  421  (e.g., from camera origin  410  to point i 2 ), and length  422  (e.g., from camera origin  410  to point i 1 ). Lengths  419 ,  421 , and  422  may be determined using camera parameters. Angle (a)  418  may be determined from lengths  419 ,  421 , and  422  using triangle equations. Angle (a)  418  may be substituted in equation 7 to determine angle (B)  417 . Angle (Y)  415  may be calculated using equation 6 by substituting known angle (B). Distances  414  and  416  may be determined using triangle equations. Furthermore, determined distances  414  (e.g., D(P 1 , O)) and  416  (e.g., D(P 2 , O)) may be used to calculate an emitted radiation intensity of the thermal radiation source of moving object of  FIG. 3  using equations 2 and 3, respectively. 
     In some embodiments, a speed of the moving object may be calculated using real world coordinates from two time identified (e.g., time stamped) thermal images. In this regard, processing component  110  may be adapted to determine real world coordinates of points  404   b  and  406   b,  as described herein. Processing component  110  may be adapted to subtract real world coordinates of  404   b  from real world coordinates of  406   b  to determine a distance traveled by the moving object relative to fixed camera origin  410  (e.g., camera origin  410  of image capture component  130 ). Processing component  110  may be further adapted to determine a time of thermal image captured at time T 1  (e.g., a first time) and a time of thermal image captured at time T 2  (e.g., a second time). Processing component  110  may be adapted to calculate an elapsed time by subtraction of the first time from the second time. Speed of the moving object may be calculated by dividing the distance traveled by the elapsed time. 
     In another embodiment, real world coordinates of point  404   b  and/or point  406   b  may be determined using the relational formula of equation 8. 
     
       
         
           
             
               
                 
                   
                     
                       
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     Equation 8 describes the relation between the real world points  404   b  or  406   b  captured by camera component  101  and their respective equivalent points i 1  or i 2  at image plane  402  of camera component  101 . 
     Equation 8 may be re-written in the form of equation 9.
 
 x=C*T*P    (equation 9)
 
where, for example,
     x is the homogenous coordinates of pixel i 1     

     
       
         
           
             
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     Matrices C and T of Equation 8 may be determined using camera parameters of camera component  101 . For example, camera matrix C (e.g., intrinsic camera parameters) includes terms fx and fy. Terms fx and fy are focal length (e.g., focal length (f)  419  of camera component  101 ) multiplied by a resolution of camera component  101  (e.g., resolution of unit cells  232 ), where resolution is expressed in pixels per unit length. Terms cx and cy of camera matrix C are offset (e.g., offset of the origin  410  of the image capture component) multiplied by the resolution of camera component  101 . 
     Transformation matrix T may include parameters (e.g., extrinsic camera parameters) such as height (h)  423  of camera component  101  from a surface  435 , pan angle (pa)  425  of camera component  101 , and tilt angle (ta)  426  of camera component  101 . Parameters of transformation matrix T depend on installation specific camera parameters. For example, in a stationary installation, camera height (h)  423  may be measured once, by a laser and/or any appropriate distance measuring device and stored in memory component  120  and/or provided to processing component  110 . Height  423  measurement may be used for one or more transformation matrices. Pan angle  425  and tilt angle  426  may be measured with an external instrument such as a gyroscope and stored in memory component  120  and/or provided to processing component  110 . However, in some embodiments, pan angle  425  and/or tilt angle  426  may be altered and/or updated to capture one or more perspectives of scene  170 . Thus, there is a desire to efficiently and reliably accommodate updated pan  425  and tilt  426  terms in transformation matrix T. In some embodiments, a vanishing point may be used to determine pan angle  425  and tilt angle  426 , as described herein. Processing component  110  may receive camera parameters via image capture interface component  136  and/or communication component  152  to integrate within equation 8. Processing component  110  may store received camera parameters in memory component  120 . 
     Real world coordinates of points  404   b  and/or  406   b  may be determined using the relational formula of equation 8 after camera and transformation matrices are completed. Lengths  414  (e.g., D(P 1 , O)) and  416  (e.g., D(P 2 , O)) may be determined from real world coordinates of points  404   b  and/or  406   b.  Furthermore, determined length  414  and measured radiation intensity of pixel i 1  may be used to calculate an emitted radiation intensity of the thermal radiation source of  FIG. 3  using equation 2. Determined length  416  (e.g., D(P 2 , O)) and measured radiation intensity value of pixel i 2  may be used to calculate an emitted radiation intensity of the thermal radiation source of  FIG. 3  using equation 3. It will be appreciated that in various embodiments as described herein, real world coordinates may be determined from at least one or more thermal images of a moving object and/or using intrinsic and extrinsic camera parameters readily available to a user. 
       FIGS. 5 and 6  illustrate locations of pixels (e.g.,  404   a  of pixel i 1  and  406   a  of pixel i 2 ) on an image plane  402  corresponding to measured radiation intensity values of pixel i 1  and pixel i 2  of  FIG. 4  in accordance with embodiments of the disclosure. Real world points  404   b  (P 1 ) and  406   b  (P 2 ) are projected onto image plane  402  at locations  404   a  and  406   a,  respectively. As shown in  FIGS. 5 and 6 , image plane  402  includes image plane coordinate system  408 . Locations  404   a  of pixel i 1  and  406   a  of pixel i 2  may be used to determine real world coordinates of points  404   b  and  406   b,  as described herein. 
       FIGS. 7A and 7B  illustrate examples of using vanishing points (e.g.,  710  and  780 ) to determine camera parameters in accordance with embodiments of the disclosure. As described herein, the camera matrix C and transformation matrix T of equation 8 may be used to determine real world coordinates of points  404   b  and  406   b.  Camera matrix C may be determined using intrinsic camera parameters focal length  419 , resolution, and camera origin offset, as described herein. In some embodiments, intrinsic parameters are constant and may be retrieved from memory component  120  by processing component  110  for use in generating camera matrix C of equation 8. Transformation matrix T may be determined from camera height (h)  423 , pan angle (pa)  425 , and tilt angle (ta)  426  (e.g., extrinsic parameters), as described herein. 
     Generally, extrinsic parameters may be application specific (e.g., such as imaging a roadway scene  170 , a pedestrian path scene  170 , or a railway scene  170  in multiple directions, and/or in multiple perspectives). In some embodiments, camera height (h)  423  may be fixed and determined by an external device, as described herein. However, pan angle (pa)  425 , and/or tilt angle (ta)  426  may be adjusted by imaging system  100  in one or more perspective views of scene  170 . An external device such as a gyroscope may be used to measure pan angle  425  and/or tilt angle  426 . However, as discussed here, external devices may add complexity and may be cumbersome to implement. 
     As shown in  FIG. 7A , in one embodiment, pan angle  425  and/or tilt angle  426  may be determined for camera component  101  using vanishing point  710 . Vanishing point  710  is a point at which parallel lines of a captured scene converge on image plane  402 . Although vanishing point  710  is not within the four corners of image plane  402 , it can be implied. For example, rail tracks  730  run parallel in the real world. Unlike the real world, parallel lines of rail tracks  730  in scene  170  converge on image plane  402  at horizontal line  740  and intersect at point  710  (e.g., vanishing point  710 ). Vanishing point  710  coordinates on image plane  402  may be used to determine pan angle  425  and/or tilt angle  426  of camera component  101 . 
       FIG. 7B  illustrates an example of an image  720  of a scene  770  to determine a vanishing point  780 . Scene  770  shows a roadway  750  and cars  760   a,    760   b,  and  760   c  travelling on roadway  750 . Parallel lines  751  and  752  within scene  770  are projected onto image  720 . Parallel lines  751  and  752  converge in image  720  and intersect at vanishing point  780  external to image plane  720 . Information from vanishing point  780  may be used to determine pan angle  425  and/or tilt angle  426  using processing component  110 . In this regard, one or more transformation matrix parameters may be determined using vanishing point  780 . 
       FIG. 8  illustrates a process of determining emitted radiation intensity of a moving object in accordance with an embodiment of the disclosure. 
     In block  805 , image capture component  130  of camera component  101  may be configured to capture one or more successive images of scene  170  and provide captured images to processing component  110 . For example, scene  170  may be a roadway scene, a pedestrian path scene, or a railway scene. Camera component  101  of imaging system  100  may be mounted to a pedestal or a stationary fixture. Camera component  101  may be configured to capture images of scene  170  in multiple directions and/or in multiple perspectives. In some embodiments, camera component  101  may be configured to capture one or more successive images of roadway  750 . 
     In block  810 , processing component  110  may select an object in scene  170  on one or more captured images. In some embodiments, the object may be a moving vehicle. The moving vehicle may be emitting a substantially constant thermal radiation within scene  170 . Processing component  110  may process successive captured images and select a pixel with a corresponding highest measured radiation intensity associated with the moving vehicle from each captured image. 
     In block  815 , processing component  110  may determine real world coordinates of the object associated with the selected pixel. For example, processing component  110  may determine real world coordinates of point  404   b  and/or point  406   b  on image plane  402 . In one embodiment, real world coordinates of point  404   b  and/or point  406   b  may be determined using equation 8, as described herein. In another embodiment, real world coordinates of point  404   b  and point  406   b  may be determined using an angle  418  and measured radiation intensities of pixels i 1  and pixel i 2 , and using equations 5, 6 and 7, as described herein. 
     In block  820 , a distance from image capture component  130  to points  404   b  and/or  406   b  may be determined using determined real world coordinates of equation 8, and/or equations 4 through 7. 
     In block  825 , emitted radiation intensity of the object may be determined using equation 1A by substituting the distance determined in block  820 , and measured radiation intensity of pixel i 1  and/or pixel i 2 . 
       FIG. 9  illustrates a process of determining real world coordinates of a moving object using camera calibration parameters in accordance with an embodiment of the disclosure. As discussed, equation 8 describes the relation between real world coordinates of points  404   b  and  406   b  and their respective equivalent image plane  402  locations  404   a  and  406   a.    
     In block  905 , processing component  110  may be configured to identify a highest measured radiation intensity of an object within scene  170  on one or more captured thermal images, such as measured radiation intensity of pixel i 1  on a first thermal image and measured radiation intensity of pixel i 2  on a second thermal image. 
     In block  910 , processing component  110  may be configured to determine locations on image plane  402  associated with measured radiation intensity values of pixel i 1  and/or pixel i 2 , respectively. Measured radiation intensity of pixel i 1  on the first thermal image corresponds to location  404   a.  Measured radiation intensity of pixel i 2  on the second thermal image corresponds with location  406   a.    
     In block  915 , processing component  110  may be configured to determine intrinsic camera parameters, such as intrinsic parameters included in the camera matrix C of equation 8. As discussed, in some embodiments, intrinsic camera parameters may include terms fx and fy. Terms fx and fy are focal length multiplied by a resolution of camera component  101 , where resolution is expressed in pixels per unit length. Furthermore, terms cx and cy of equation 8 are camera component  101  offset multiplied by a resolution of camera component  101 . 
     In block  920 , extrinsic parameters of equation 8 may be determined. As discussed, transformation matrix T of equation 8 includes extrinsic parameters; camera height (h)  423  of camera component  101  from a surface  435 , pan angle (pa)  425 , and tilt angle (ta)  426 . A vanishing point (e.g., vanishing point  710 ) on image plane  402  may be used to determine extrinsic parameters pan angle  425  and tilt angle  426 , as described herein. 
     In block  925 , completed camera matrix C and transformation matrix T may be used in equation 8 to translate locations  404   a  and/or  406   a  on image plane  402  to real world coordinates of points  404   b  and/or  406   b,  respectively. 
       FIG. 10  illustrates a process of determining real world coordinates of a moving object using measured radiation intensity values (e.g., such as measured radiation intensity values of i 1  and/or i 2 ) in accordance with an embodiment of the disclosure. 
     In block  1005 , processing component  110  may be configured to identify a highest measured radiation intensity of an object within scene  170  on at least two successive captured thermal images, such as measured radiation intensity of i 1  on a first thermal image and measured radiation intensity of i 2  on a second thermal image. 
     In block  1010 , processing component  110  may be configured to determine locations  404   a  and  406   a  corresponding to pixels i 1  and i 2 , respectively, on image plane  402 . 
     In block  1015 , processing component  110  may be configured to determine an angle (a)  418  defined by the camera origin  410  and the image plane  402  locations  404   a  of pixels i 1  and  406   a  of pixel i 2 . 
     In block  1020 , real world coordinates of points  404   b  and  406   b  corresponding to locations  404   a  and  406   a  on image plane  402 , respectively, may be determined using measured radiation intensity values of pixel i 1  and pixel i 2 , and determined angle (a)  418  in equations 4 through 7, as described herein. 
     In view of the present disclosure, it will be appreciated that determining an actual emitted radiation intensity of an object on a thermal image using an imaging camera implemented in accordance with various embodiments set forth herein may provide for an automated and reliable method of determining a distance attenuation of thermal radiation. In this regard, by selecting an object within a scene  170 , identifying highest measured radiation intensity associated with the object, locating pixels of the measured radiation intensity on an image plane, determining real world coordinates of the object, and using vanishing points for determining camera parameters, thermal radiation distance attenuation may be determined efficiently and effectively. 
     Where applicable, various embodiments provided by the present disclosure can be implemented using hardware, software, or combinations of hardware and software. Also where applicable, the various hardware components and/or software components set forth herein can be combined into composite components comprising software, hardware, and/or both without departing from the spirit of the present disclosure. Where applicable, the various hardware components and/or software components set forth herein can be separated into sub-components comprising software, hardware, or both without departing from the spirit of the present disclosure. In addition, where applicable, it is contemplated that software components can be implemented as hardware components, and vice-versa. 
     Software in accordance with the present disclosure, such as program code and/or data, can be stored on one or more computer readable mediums. It is also contemplated that software identified herein can be implemented using one or more general purpose or specific purpose computers and/or computer systems, networked and/or otherwise. Where applicable, the ordering of various steps described herein can be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein. 
     Embodiments described above illustrate but do not limit the invention. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the following claims.