PATENT DOCUMENT

Publication Number: US-9086738-B2
Application Number: US-201313796502-A
Country: US
Kind Code: B2

Title: Multi-surface optical tracking system

Abstract:
An optical tracking device that is capable of operation on both glossy and diffuse surfaces includes at least one housing, at least one light source, and at least one sensor. The light source emits light toward a surface on which the housing is moved and the sensor receives the light emitted by the light source after it is reflected off of the surface. The light source is oriented such that the angle of incidence of the emitted light corresponds to Brewster&#39;s angle. The sensor may be also oriented such that the angle of reflection of the reflected light corresponds to Brewster&#39;s angle. The light emitted by the light source may be polarized to increase the p-polarization of the emitted light and/or the light received by the sensor may be filtered to block s-polarized portions of the reflected light.

Claims:
We claim: 
     
       1. A method for operating an optical tracking device, the method comprising:
 configuring the optical tracking device with at least one light source that emits light towards at least one surface on which the optical tracking device moves and at least one sensor that receives light reflected off of the at least one surface, the optical tracking device tracks movement in relation to the at least one surface using the light received by the at least one sensor; 
 orienting the at least one sensor such that an angle of reflection of the light received by the at least one sensor reflected off of the at least one surface corresponds to Brewster&#39;s angle in response to detection that an intensity of the light received by the at least one sensor exceeds a capability of the at least one sensor; and 
 orienting the at least one sensor such that the angle of reflection of the light received by the at least one sensor reflected off of the at least one surface corresponds to a different angle than Brewster&#39;s angle in response to detection that the intensity of the light received by the at least one sensor is below a threshold. 
 
     
     
       2. The method of  claim 1 , further comprising:
 orienting the at least one light source such that an angle of incidence of the emitted light corresponds to Brewster&#39;s angle. 
 
     
     
       3. The method of  claim 2 , wherein said operation of orienting the at least one light source is performed in response to detection that the intensity of the light received by the at least one sensor exceeds the capability of the at least one sensor. 
     
     
       4. The method of  claim 1 , further comprising:
 polarizing the light emitted by the at least one light source towards at least one surface to increase a p-polarization percentage of the light emitted by the at least one light source. 
 
     
     
       5. The method of  claim 4 , further comprising:
 collimating the light emitted by the at least one light source towards at least one surface, wherein said operation of polarizing the light emitted by the at least one light source polarizes the collimated light. 
 
     
     
       6. The method of  claim 4 , wherein said operation of polarizing the light emitted by the at least one light source is performed in response to detection that the intensity of the light received by the at least one sensor exceeds the capability of the at least one sensor. 
     
     
       7. The method of  claim 1 , further comprising:
 filtering the light received by the at least one sensor reflected off of the at least one surface to block at least part of a s-polarized portion of the light reflected off of the at least one surface. 
 
     
     
       8. The method of  claim 7 , wherein said operation of filtering the light received by the at least one sensor reflected off of the at least one surface to block at least part of a s-polarized portion of the light reflected off of the at least one surface is performed in response to detection that the intensity of the light received by the at least one sensor exceeds the capability of the at least one sensor. 
     
     
       9. The method of  claim 1 , wherein said operation of orienting the at least one sensor such that the angle of reflection of the light received by the at least one sensor reflected off of the at least one surface corresponds to Brewster&#39;s angle is performed in response to at least one additional sensor detecting that the intensity of the light received by the at least one sensor exceeds the capability of the at least one sensor. 
     
     
       10. The method of  claim 1 , wherein said operation of orienting the at least one sensor such that the angle of reflection of the light received by the at least one sensor reflected off of the at least one surface corresponds to the different angle than Brewster&#39;s angle in response to at least one additional sensor detecting that the intensity of the light received by the at least one sensor is below the threshold. 
     
     
       11. The method of  claim 9 , wherein the at least one additional sensor comprises an ambient light detector. 
     
     
       12. The method of  claim 1 , further comprising orienting the at least one light source such that an angle of incidence of the emitted light is other than Brewster&#39;s angle. 
     
     
       13. The method of  claim 12 , wherein said operation of orienting the at least one light source such that the angle of incidence of the emitted light is other than Brewster&#39;s angle is performed in response to detection that the intensity of the light received by the at least one sensor is below the threshold. 
     
     
       14. The method of  claim 10 , wherein the at least one additional sensor comprises an ambient light detector. 
     
     
       15. The method of  claim 1 , wherein the threshold corresponds to a minimum light intensity the at least one sensor is capable of detecting. 
     
     
       16. The method of  claim 1 , wherein said operation of orienting the at least one sensor such that the angle of reflection of the light received by the at least one sensor reflected off of the at least one surface corresponds to Brewster&#39;s angle reorients the at least one sensor to change the angle of reflection from an angle other than Brewster&#39;s angle to Brewster&#39;s angle. 
     
     
       17. The method of  claim 1 , wherein the optical tracking device comprises a mouse. 
     
     
       18. The method of  claim 1 , wherein the at least one light source comprises at least one laser, incandescent bulb, light emitting diode, or organic light emitting diode. 
     
     
       19. The method of  claim 1 , wherein the optical tracking device comprises a stylus. 
     
     
       20. The method of  claim 1 , wherein said operation of orienting the at least one sensor such that the angle of reflection of the light received by the at least one sensor reflected off of the at least one surface corresponds to the different angle than Brewster&#39;s angle reorients the at least one sensor to change the angle of reflection from Brewster&#39;s angle to the different angle.

Description:
TECHNICAL FIELD 
     This disclosure relates generally to optical tracking devices, and more specifically to optical tracking devices that can function on both glossy and diffuse surfaces. 
     BACKGROUND 
     Optical tracking devices, which may include optical tracking input devices such as optical computer mice, typically track movement of the respective device on a surface. Such movement may be tracked utilizing one or more sensors that detect light emitted by one or more light sources and reflected and/or diffused by the surface. However, differences in reflective and/or diffusive properties of different types of surfaces may cause problems for movement tracking when the optical tracking devices are utilized on glossy surfaces (such as glass) as opposed to diffuse surfaces (such as wood). 
     SUMMARY 
     The present disclosure discloses apparatuses and methods for operating optical tracking devices. An optical tracking device that may be capable of operation on both glossy and diffuse surfaces may include at least one housing, at least one light source, and at least one sensor. The light source may emit light toward a surface on which the housing is moved and the sensor may receive the light emitted by the light source after it is reflected off of the surface. The light source may be oriented such that the angle of incidence of the emitted light corresponds to Brewster&#39;s angle and/or the sensor may be oriented such that the angle of reflection of the reflected light corresponds to Brewster&#39;s angle. The light emitted by the light source may be polarized to increase the p-polarization of the emitted light and/or the light received by the sensor may be filtered to block s-polarized portions of the reflected light. In this way, the optical tracking device may be operated such that the intensity of the reflected light does not exceed the capability of the sensor. 
     In some implementations, the optical tracking devices may be manufactured to be configured as described above. However, in other implementations, various factors discussed above (such as light source and/or sensor orientation, polarization of emitted and/or received light, and so on) may be adjusted in response to detecting that the intensity of reflected light exceeds the capability of the sensor and/or is below a threshold (such as the sensor&#39;s ability to detect). 
     It is to be understood that both the foregoing general description and the following detailed description are for purposes of example and explanation and do not necessarily limit the present disclosure. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate subject matter of the disclosure. Together, the descriptions and the drawings serve to explain the principles of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a chart illustrating intensities of diffuse and specular light reflected from glossy surfaces at different angles. 
         FIGS. 2A and 2B  illustrate the differences between an optical tracking device operating on a glossy surface and a diffuse surface. 
         FIG. 3A  is a side view of first implementation of an optical tracking device that may be capable of operation on both glossy and diffuse surfaces. 
         FIG. 3B  is a side view of second implementation of an optical tracking device that may be capable of operation on both glossy and diffuse surfaces. 
         FIG. 4A  is a side view of third implementation of an optical tracking device that may be capable of operation on both glossy and diffuse surfaces. 
         FIG. 4B  is a side view of fourth implementation of an optical tracking device that may be capable of operation on both glossy and diffuse surfaces. 
         FIG. 5  is a flow chart illustrating a first example method for operating optical tracking devices. This method may be performed by the optical tracking devices of  FIGS. 3A-4B . 
         FIG. 6  is a flow chart illustrating a second example method for operating optical tracking devices. This method may be performed by the optical tracking devices of  FIGS. 3A-4B . 
     
    
    
     DETAILED DESCRIPTION 
     The description that follows includes apparatuses and methods that embody various elements of the present disclosure. However, it should be understood that the described disclosure may be practiced in a variety of forms in addition to those described herein. 
     An optical tracking device that may be capable of operation on both glossy and diffuse surfaces may include at least one housing, at least one light source, and at least one sensor. The light source may emit light toward a surface on which the housing is moved and the sensor may receive the light emitted by the light source after it is reflected off of the surface. The light source may be oriented such that the angle of incidence of the emitted light corresponds to Brewster&#39;s angle and/or the sensor may be oriented such that the angle of reflection of the reflected light corresponds to Brewster&#39;s angle. The light emitted by the light source may be polarized to increase the p-polarization of the emitted light and/or the light received by the sensor may be filtered to block s-polarized portions of the reflected light. In this way, the optical tracking device may be operated such that the intensity of the reflected light does not exceed the capability of the sensor. 
       FIG. 1  is a chart illustrating intensities of diffuse  101  and specular  102  light reflected from glossy surfaces (such as glass) at different angles. As can be seen by the chart, light that is directly reflected by the glossy surface (specular light) has a much greater intensity throughout much of the possible angles at which the light is reflected off of a glossy surface than light that is diffused (diffuse light) by the glossy surface. Further, as can also be seen by the chart, the intensity of the specular light varies steeply with the angle. Large differences between the intensity of diffuse and specular light can cause the intensity of the specular light to exceed the sensing capabilities of optical tracking device sensors. 
     It should be noted, the intensity of specular light reflected from diffuse surfaces (such as wood) does not vary steeply with angle. As such, optical tracking devices may operate well when used on diffuse surfaces but may not be capable of operation on glossy surfaces due to the difference between the intensity of the diffuse and specular light. 
       FIGS. 2A and 2B  illustrate the differences between optical tracking devices  201   a  (which may be optical mice) and  201   b  operating ( 200 A and  200 B) respectively on a glossy surface  202   a  and a diffuse surface  202   b . As can be seen in  FIG. 2A , the optical tracking device  201   a  includes a light source  203   a  that emits light  206   a  with an angle of incidence θi at the surface  202   a . The optical tracking device  201   a  also includes a sensor A  204   a  and a sensor B  205   a . As illustrated, the surface  202   a  may diffuse a portion of the emitted light  206   a . This diffuse light  209   a  may be received by the sensor A  204   a  and/or the sensor B  205   a . However, the surface  202   a  also reflects a portion of the emitted light  206   a  with an angle of reflection θr. This specular light  208   a  is received by the sensor B  205   a . As described above with respect to  FIG. 1 , the specular light  208   a  may be much greater in intensity than the diffuse light  209   a . This may cause the sensor B  205   a  to saturate and not be utilizable to detect motion even when the sensor A  204   a  is not caused to saturate and it utilizable to detect motion. 
     By way of contrast, as can be seen in  FIG. 2B , the optical tracking device  201   b  also includes a light source  203   b  that emits light  206   b  with an angle of incidence θ i  at the surface  202   b . The optical tracking device  201   b  also includes a sensor A  204   b  and a sensor B  205   b . As illustrated, the surface  202   a  diffuses the emitted light  206   b . This diffused light  209   b  may be received by the sensor A  204   b  and/or the sensor B  205   b . However, even if the diffuse light  209   b  is greater in intensity than the diffuse light  209   a  illustrated in  FIG. 2A , the surface  202   b  does not reflect specular light to the is received by the sensor B  205   b . As such, neither the sensor A  204   b  nor the sensor B  205   b  may be caused to saturate. This, the optical tracking device  201   b  is capable of operation on the diffuse surface  202   b  whereas the optical tracking device  201   a  may not be capable of operation on the glossy surface  202   a  due to intensity differences in the diffuse light  209   a  and the specular light  208   a.    
     Returning to  FIG. 1 , line  103  illustrates the intensity of diffuse light and specular light reflected off of glossy surfaces that has been reduced by one or more techniques of the present disclosure. As can be seen by line  103 , utilization of techniques presented by the present disclosure may reduce the intensity the specular light such that the difference in intensity between the diffuse and specular light does not exceed the capabilities of one or more sensors of an optical tracking device. In this way, an optical tracking device may be provided that may be capable of operation on both glossy and diffused surfaces. 
       FIG. 3A  is a side view of first implementation of an optical tracking device  301   a  that may be capable of operation  300 A on both glossy and diffuse surfaces. As can be seen in  FIG. 3A , the optical tracking device  301   a  includes a light source  303   a  (which may be at one laser, at least one incandescent bulb, at least one light emitting diode, at last one organic light emitting diode, and/or at least one other lighting source) that emits unpolarized light  306   a  with an angle of incidence corresponding to Brewster&#39;s angle (θB), which is approximately 53 degrees (such as 55 degrees, 54 degrees, and so on), at the surface  302   a . The optical tracking device  301   a  also includes a sensor  305   a . As illustrated, the glossy surface  302   a  may diffuse a portion of the unpolarized emitted light  306   a . This diffuse unpolarized light  309   a  may be received by the sensor  305   a . However, emitting light at the glossy surface  302   a  with an angle of incidence corresponding to Brewster&#39;s angle may cause only s-polarized light to be reflected by the glossy surface  302   a  (which may be reflected with an angle of reflection corresponding to Brewster&#39;s angle) whereas p-polarized light passes through ( 310   a ) the glossy surface  302   a  (which may also be diffused by non-glossy features  311   a  within the glossy surface  302   a  resulting in diffuse light  312   a ). As such, the intensity of the specular light  308   a  may be reduced. Thus, the sensor  305   a  may receive the diffuse unpolarized light  309   a , diffuse p-polarized light  312   a , and the s-polarized specular light  308   a  without causing the sensor  305   a  to saturate. In this way, the optical tracking device  301   a  may be capable of operating on glossy or diffuse surfaces. 
     It should be noted that although the optical tracking device  301   a  is described as capable of operation on diffuse surfaces with an angle of incidence and an angle of reflection corresponding to Brewster&#39;s angle, in some cases operation on a diffuse surface may cause the intensity of light received by the sensor  305   a  to be below the sensing capabilities of the sensor  305   a . In such cases, the orientation of the light source  303   a  and/or the sensor  305   a  may be changed such that the angle of incidence and the angle of reflection correspond to Brewster&#39;s angle from another angle when light received by the sensor  305   a  exceeds the sensor&#39;s capabilities. Similarly, the orientation of the light source  303   a  and/or the sensor  305   a  may be changed such that the angle of incidence and the angle of reflection correspond to another angle from Brewster&#39;s angle when light received by the sensor  305   a  is below a threshold (such as the sensor&#39;s ability to detect). 
     In some implementations, the determination of whether or not light received by the sensor  305   a  exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect may be performed utilizing data from the sensor  305   a . In other implementations, the optical tracking device  301   a  may include one or more ambient light detectors (not shown) (which may be positioned near the sensor  305   a ) and data from the ambient light detector(s) may be utilized to determine whether or not the light exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect. 
       FIG. 3B  is a side view of second implementation of an optical tracking device  301   b  that may be capable of operation  300 B on both glossy and diffuse surfaces. As can be seen in  FIG. 3B , the optical tracking device  301   b  includes a light source  303   b  (which may be at one laser, at least one incandescent bulb, at least one light emitting diode, at last one organic light emitting diode, and/or at least one other lighting source) that emits p-polarized light  306   b  with an angle of incidence corresponding to Brewster&#39;s angle (θB), which is approximately 53 degrees, at the surface  302   b . The optical tracking device  301   b  also includes a sensor  305   b . As illustrated, the glossy surface  302   b  may diffuse a portion of the p-polarized emitted light  306   b  and a portion of the p-polarized emitted light  306   b  passes through ( 310   b ) the glossy surface  302   b  (which may also be diffused by non-glossy features  311   b  within the glossy surface  302   b  resulting in diffuse light  312   b ). This diffuse unpolarized light  309   b  may be received by the sensor  305   b . However, as all of the p-polarized emitted light  306   b  is either diffused or passes through the glossy surface, no portion is reflected (specular light) by the glossy surface  302   b . As such, the intensity of the light received by the sensor  305   b  is reduced and the sensor  305   b  may receive the diffuse p-polarized light  309   b  and/or  312   b  without causing the sensor  305   a  to saturate. In this way, the optical tracking device  301   b  may be capable of operating on glossy or diffuse surfaces. 
     It should be noted that although the optical tracking device  301   b  is described as capable of operation on diffuse surfaces with 100% p-polarization an angle of incidence corresponding to Brewster&#39;s angle, in some cases operation on a diffuse surface may cause the intensity of light received by the sensor  305   b  to be below the sensing capabilities of the sensor  305   b . In such cases, the percentage of p-polarization of the light emitted by the light source  303   b  in relation to the percentage of s-polarization may be varied. For example, the percentage of p-polarization of the light emitted by the light source  303   b  may be increased when light received by the sensor  305   b  exceeds the sensor&#39;s capabilities and the percentage of p-polarization of the light emitted by the light source  303   b  may be decreased when light received by the sensor  305   b  is below a threshold (such as the sensor&#39;s ability to detect). Similarly, the orientation of the light source  303   b  may be changed such that the angle of incidence corresponds to Brewster&#39;s angle from another angle when light received by the sensor  305   b  exceeds the sensor&#39;s capabilities and the orientation of the light source  303   b  may be changed such that the angle of incidence corresponds to another angle from Brewster&#39;s angle when light received by the sensor  305   b  is below a threshold (such as the sensor&#39;s ability to detect). 
     In some implementations, the determination of whether or not light received by the sensor  305   b  exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect may be performed utilizing data from the sensor  305   b . In other implementations, the optical tracking device  301   b  may include one or more ambient light detectors (not shown) (which may be positioned near the sensor  305   b ) and data from the ambient light detector(s) may be utilized to determine whether or not the light exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect. 
       FIG. 4A  is a side view of third implementation of an optical tracking device  401   a  that may be capable of operation  400 A on both glossy and diffuse surfaces. As can be seen in  FIG. 4A , the optical tracking device  401   a  includes a light source  403   a  that emits light that is collimated by a collimating optic component  414   a , polarized by a polarizing optic component  415   a  (which may increase a p-polarized percentage of the light), and projected with an angle of incidence corresponding to Brewster&#39;s angle (θB) at the glossy table surface  402   a.    
     As illustrated, the light source  403   a  is a light emitting diode. However, in other implementations, the light source  403   a  may be any kind of light source, such as at one laser (which may be utilized without the collimating optic component  414   a ), at least one incandescent bulb, at last one organic light emitting diode, and/or at least one other lighting source. 
     The optical tracking device  401   a  also includes an optical sensor  405   a  that receives light via an imaging optic component  416   a . As illustrated, the glossy table surface  402   a  may diffuse a portion of the projected light, reflect (with an angle of reflection corresponding to Brewster&#39;s angle (θ B )) a portion of the projected light (such as the percentage that is p-polarized), and allow a portion of the projected light to pass through the glossy table surface  402   a  (such as the portion that is s-polarized). This diffuse and p-polarized reflected light may be received by the optical sensor  405   a . As such, the intensity of the light received by the optical sensor  405   a  is reduced and the optical sensor  405   a  may receive the diffuse light and the p-polarized reflected light without causing the optical sensor  405   a  to saturate. In this way, the optical tracking device  401   a  may be capable of operating on glossy or diffuse surfaces. 
     It should be noted that although the optical tracking device  401   a  is described as capable of operation on diffuse surfaces with some percentage of p-polarization and angle of incidence and reflection corresponding to Brewster&#39;s angle, in some cases operation on a diffuse surface may cause the intensity of light received by the optical sensor  405   a  to be below the sensing capabilities of the optical sensor  405   a . In such cases, the percentage of p-polarization of the light emitted by the light source  403   a  in relation to the percentage of s-polarization may be varied. For example, the percentage of p-polarization of the light emitted by the light source  403   a  may be increased by the polarization optic component  414   a  when light received by the optical sensor  405   a  exceeds the sensor&#39;s capabilities and the percentage of p-polarization of the light emitted by the light source  403   a  may be decreased by the polarization optic component  414   a  when light received by the optical sensor  405   a  is below a threshold (such as the sensor&#39;s ability to detect). Similarly, the orientation of the light source  403   a  and/or the optical sensor  405   a  may be changed such that the angle of incidence and the angle of reflection correspond to Brewster&#39;s angle from another angle when light received by the optical sensor  405   a  exceeds the sensor&#39;s capabilities and/or changed such that the angle of incidence and the angle of reflection correspond to another angle from Brewster&#39;s angle when light received by the optical sensor  405   a  is below a threshold (such as the sensor&#39;s ability to detect). 
     In some implementations, the determination of whether or not light received by the optical sensor  405   a  exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect may be performed utilizing data from the optical sensor  405   a . In other implementations, the optical tracking device  401   a  may include one or more ambient light detectors (not shown) (which may be positioned near the optical sensor  405   a ) and data from the ambient light detector(s) may be utilized to determine whether or not the light exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect. 
       FIG. 4B  is a side view of fourth implementation of an optical tracking device  401   b  that may be capable of operation  400 B on both glossy and diffuse surfaces. As can be seen in  FIG. 4B , the optical tracking device  401   b  includes a light source  403   b  that emits light that is collimated by a collimating optic component  414   b , polarized by a polarizing optic component  415   b  (which may increase a p-polarized percentage of the light), and projected with an angle of incidence corresponding to Brewster&#39;s angle (θB) at the glossy table surface  402   b.    
     As illustrated, the light source  403   b  is a light emitting diode. However, in other implementations, the light source  403   b  may be any kind of light source, such as at one laser (which may be utilized without the collimating optic component  414   b ), at least one incandescent bulb, at last one organic light emitting diode, and/or at least one other lighting source. 
     The optical tracking device  401   b  also includes an optical sensor  405   b  that receives light via an imaging optic component  416   b  that has been filtered by polarizer optic filtering component  417   b . As illustrated, the glossy table surface  402   b  may diffuse a portion of the projected light, reflect (with an angle of reflection corresponding to Brewster&#39;s angle (θ B )) a portion of the projected light (such as the percentage that is p-polarized), and allow a portion of the projected light to pass through the glossy table surface  402   b  (such as part of the portion that is s-polarized). This diffuse and p-polarized reflected light may be received by the optical sensor  405   b  after additional filtering of remaining s-polarized portions of the light is performed by the polarizer optic filtering component  417   b . As such, the intensity of the light received by the optical sensor  405   b  is reduced and the optical sensor  405   b  may receive the diffuse light and the p-polarized reflected light without causing the optical sensor  405   b  to saturate. In this way, the optical tracking device  401   b  may be capable of operating on glossy or diffuse surfaces. 
     It should be noted that although the optical tracking device  401   b  is described as capable of operation on diffuse surfaces with some percentage of p-polarization and angle of incidence and reflection corresponding to Brewster&#39;s angle, in some cases operation on a diffuse surface may cause the intensity of light received by the optical sensor  405   b  to be below the sensing capabilities of the optical sensor  405   b . In such cases, the percentage of p-polarization of the light emitted by the light source  403   b  in relation to the percentage of s-polarization may be varied. For example, the percentage of p-polarization of the light emitted by the light source  403   b  may be increased by the polarization optic component  414   b  when light received by the optical sensor  405   b  exceeds the sensor&#39;s capabilities and the percentage of p-polarization of the light emitted by the light source  403   b  may be decreased by the polarization optic component  414   b  when light received by the optical sensor  405   b  is below a threshold (such as the sensor&#39;s ability to detect). Similarly, the orientation of the light source  403   b  and/or the optical sensor  405   b  may be changed such that the angle of incidence and the angle of reflection correspond to Brewster&#39;s angle from another angle when light received by the optical sensor  405   b  exceeds the sensor&#39;s capabilities and/or changed such that the angle of incidence and the angle of reflection correspond to another angle from Brewster&#39;s angle when light received by the optical sensor  405   a  is below a threshold (such as the sensor&#39;s ability to detect). Moreover, the percentage of s-polarization of the light blocked by the polarizer optic filtering component  417   b  may be increased when light received by the optical sensor  405   b  exceeds the sensor&#39;s capabilities and the percentage of s-polarization of the light blocked by the polarizer optic filtering component  417   b  may be decreased when light received by the optical sensor  405   b  is below a threshold (such as the sensor&#39;s ability to detect). 
     In some implementations, the determination of whether or not light received by the optical sensor  405   b  exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect may be performed utilizing data from the optical sensor  405   b . In other implementations, the optical tracking device  401   b  may include one or more ambient light detectors (not shown) (which may be positioned near the optical sensor  405   b ) and data from the ambient light detector(s) may be utilized to determine whether or not the light exceeds the sensor&#39;s capabilities and/or is below the sensor&#39;s ability to detect. 
       FIG. 5  illustrates a first example method  500  for operating an optical tracking device. The method  500  may be performed by the optical tracking devices of  FIGS. 3A-4B . The flow begins at block  501  and proceeds to block  502  where an optical tracking device is operated. The optical tracking device may include at least one light source and at least one sensor. 
     The flow then proceeds to block  503  where the light source is configured to emit light towards a surface on which the optical tracking device moves. The flow then proceeds to block  504  where the sensor is configures to receive light reflected by the surface. 
     The flow then proceeds to block  505 . At block  505 , the light source is oriented such that the angle of incidence of the emitted light corresponds to Brewster&#39;s angle. The flow then proceeds to block  506 . 
     At block  506 , the sensor is oriented such that the angle of reflection of the reflected light corresponds to Brewster&#39;s angle. The flow then proceeds to block  507  and ends. 
     Although the method  500  is illustrated and described above as including particular operations performed in a particular order, it is understood that other arrangements of various operations are possible without departing from the scope of the present disclosure. For example, in one or more implementations, blocks  505  and  506  may be performed simultaneously, in reverse order, and so on. By way of another example, block  501  may be omitted in one or more implementations. 
       FIG. 6  illustrates a second example method  600  for operating an optical tracking device. The method  600  may be performed by the optical tracking devices of  FIGS. 3A-4B . The flow begins at block  601  and proceeds to block  602  where it is determined whether or not light intensity is correct for sensor use of an optical tracking device that includes a light source which emits light toward a surface on which the optical tracking device moves and a sensor that receives light reflected by the surface. If so, the flow returns to block  602  where it is determined whether or not the light intensity is correct for sensor use, otherwise, the flow proceeds to block  603 . 
     At block  603 , after it is determined that the light intensity is not correct for sensor use, it is determined whether the light is too intense for sensor use or not intense enough for sensor use. In some implementations, the determination of whether or not the light is too intense or not intense enough may be performed utilizing data from the sensor. In other implementations, the optical tracking device may include an ambient light detector (which may be positioned near the sensor) and data from the ambient light detector may be utilized to determine whether or not the light is too intense or not intense enough. If the light is too intense, the flow proceeds to block  604 . Otherwise, the flow proceeds to block  612 . 
     At block  604 , after it is determined that the light is too intense, it is determined whether or not to adjust the angle of incidence for emitted light of the light source to Brewster&#39;s angle. If so, the flow proceeds to block  605  where the angle of incidence for emitted light of the light source is adjusted to Brewster&#39;s angle before the flow proceeds to block  606 . Otherwise, the flow proceeds directly to block  606 . 
     At block  606 , it is determined whether or not to adjust the angle of reflection for reflected light received by the sensor to Brewster&#39;s angle. If so, the flow proceeds to block  607  where the angle of reflection for reflected light received by the sensor is adjusted to Brewster&#39;s angle before the flow proceeds to block  608 . Otherwise, the flow proceeds directly to block  608 . 
     At block  608 , it is determined whether or not to increase the p-polarization of the light source. If so, the flow proceeds to block  609  where the p-polarization of the light source is increased before the flow proceeds to block  610 . Otherwise, the flow proceeds directly to block  610 . 
     At block  610 , it is determined whether or not to increase the s-polarization filtering of the light received by the sensor. If so, the flow proceeds to block  611  where s-polarization filtering of the light received by the sensor is increased before the flow returns to block  602  and it is determined whether or not the light intensity is now correct for sensor use. Otherwise, the flow returns directly to block  602 . 
     At block  612 , after it is determined that the light is not intense enough, it is determined whether or not to adjust the angle of incidence for emitted light of the light source to an angle other than Brewster&#39;s angle. If so, the flow proceeds to block  613  where the angle of incidence for emitted light of the light source is adjusted to an angle other than Brewster&#39;s angle before the flow proceeds to block  614 . Otherwise, the flow proceeds directly to block  614 . 
     At block  614 , it is determined whether or not to adjust the angle of reflection for reflected light received by the sensor to angle other than Brewster&#39;s angle. If so, the flow proceeds to block  615  where the angle of reflection for reflected light received by the sensor is adjusted to an angle other than Brewster&#39;s angle before the flow proceeds to block  616 . Otherwise, the flow proceeds directly to block  616 . 
     At block  616 , it is determined whether or not to decrease the p-polarization of the light source. If so, the flow proceeds to block  617  where the p-polarization of the light source is decreased before the flow proceeds to block  618 . Otherwise, the flow proceeds directly to block  618 . 
     At block  618 , it is determined whether or not to decrease the s-polarization filtering of the light received by the sensor. If so, the flow proceeds to block  619  where s-polarization filtering of the light received by the sensor is decreased before the flow returns to block  602  and it is determined whether or not the light intensity is now correct for sensor use. Otherwise, the flow returns directly to block  602 . 
     Although the method  600  is illustrated and described above as including particular operations performed in a particular order, it is understood that other arrangements of various operations are possible without departing from the scope of the present disclosure. For example, blocks  604 - 611  and blocks  612 - 619  are illustrated and described as being performed in sequential order. However, in various implementations blocks  604 - 611  and/or blocks  612 - 619  may be performed in different orders and/or simultaneously. 
     Although the present disclosure has been illustrated and described as utilizing the techniques discussed herein for operating optical tracking devices such as optical mice, it is understood that this is for the purposes of example. In various cases, the techniques disclosed herein may be utilized in finger tracking and/or for other devices such as a tip of a stylus without departing from the scope of the present disclosure. 
     Further, although the present disclosure has been illustrated and described as utilizing the techniques discussed herein for operating optical tracking devices on glossy and diffuse surfaces, it is understood that this is for the purposes of example. Other utilization of the techniques disclosed herein is possible and contemplated without departing from the scope of the present disclosure. For example, the techniques discussed herein may be utilized when examining paper and/or other transparent materials are going from roll to roll in order to analyze whether or not the materials are slipping. By way of another example, the techniques discussed herein may be utilized to analyze glass surfaces such as screens, glass wafers, and so on for smudges, impurities, and/or other defects. 
     In the present disclosure, the methods disclosed may be implemented as sets of instructions or software readable by a device. Further, it is understood that the specific order or hierarchy of steps in the methods disclosed are examples of sample approaches. In other embodiments, the specific order or hierarchy of steps in the method can be rearranged while remaining within the disclosed subject matter. The accompanying method claims present elements of the various steps in a sample order, and are not necessarily meant to be limited to the specific order or hierarchy presented. 
     The described disclosure may be provided as a computer program product, or software, that may include a non-transitory machine-readable medium having stored thereon instructions, which may be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A non-transitory machine-readable medium includes any mechanism for storing information in a form (e.g., software, processing application) readable by a machine (e.g., a computer). The non-transitory machine-readable medium may take the form of, but is not limited to, a magnetic storage medium (e.g., floppy diskette, video cassette, and so on); optical storage medium (e.g., CD-ROM); magneto-optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; and so on. 
     It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes. 
     While the present disclosure has been described with reference to various embodiments, it will be understood that these embodiments are illustrative and that the scope of the disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. More generally, embodiments in accordance with the present disclosure have been described in the context or particular embodiments. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow.

Metadata:
Filing Date: 20130312
Publication Date: 20150721
Grant Date: 20150721
Priority Date: 20130312
Inventors: LEUNG OMAR SZE
LAST MATTHEW
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0317", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0317", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 51525920