Method and imager for detecting the location of objects

Abstract

A device determines the location of objects in an environment by receiving an optical image of an environment and converting the optical image of the environment into a live color digital image. The device employs software to perform an analysis of the live color digital image to determine the location of the environment having one or more lost object by using color and shape characteristics of the one or more objects. The software uses a range of the visible portion of the color space uniquely identified for the type of object in that environment and identifies those pixels in the color digital image that may be possible targets. Intensity of background and object size are used to exclude pixels as possible target objects.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of utility patent application having Ser. No. 10/921,294 filed on Aug. 19, 2004

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to a method, a system and a computer program product for determining the location of objects in an environment. More particularly, the present invention relates to a method, a device and a computer program product for determining the location of the objects in environments where the color of the object is not naturally found.

2. Description of the Prior Art:

There are many circumstances where an object is lost and determining its location is difficult due to the characteristics of the environment in which it has been lost. One such circumstance occurs during the playing of the sport of golf. Typically, the sport of golf is played on terrain having a variety of characteristics, such as grass, sand, trees, water, a specified distance, etc. It is not uncommon for a golf ball to become lost while playing golf due to the characteristics of the environment in which it is played. Once a golf ball is lost, a substantial amount of time can be spent trying to find it. This results in an increase of playing time for the player who lost the ball, as well as other players playing behind or with the player. In cases where the golf ball cannot be located, the player who lost the ball is accessed a penalty stroke increasing the player's final score.

Accordingly, there is a need for a device that detects and determines the location of an object in an environment having a variety of characteristics. There is further need for the device to be mobile. There is a further need for the device to detect the location of an object over long distances. There is a need for the device to be operable in a variety of lighting conditions. There is a need for the device to reduce glare and related image artifacts. There is a need for the device to reduce multiple reflections and shadowing in the detection of the object. There is a need for the device to decrease the amount of time required to locate an object.

SUMMARY OF THE INVENTION

According to embodiments of the present invention, a method, a device and a computer program product for determining the location of an object in an environment are provided. The method receives an optical image of an environment and converts the optical image of the environment into a live color digital image of the environment consisting of charged signals, where each charged signal was generated by a pixel in an array of a Charged Coupler Device (CCD) by photoelectric conversion.

The live color digital image depicts an environment having one or more similar objects. Software performs an analysis of the live color digital image to detect and determine the location of the one or more objects in the live color digital image of the environment by using color and shape characteristics of the one or more objects. The software uses a range of the visible portion of the color space uniquely identified for the type of object in that environment to detect and determine the location of the one or more objects in the live color digital image of the environment. When the object is a golf ball, color is defined by reflection of light and by UV stimulated emission of blue fluorescence due to the brighteners incorporated in the composition of golf balls. Color in this application may be due to the reflection of light, stimulated emission such as fluorescence, phosphorescence and alike processes separately or in combination. In the presence of sufficient sun light, the color of a golf ball is expected to be unique, a blue enhanced white not naturally found in objects. Furthermore, because a lost golf ball is only partially visible, where 1% or more of its surface may be unobstructed, the color of the golf ball is not identifiable as an object. In general, the image of a lost golf ball occupies a very small percentage of the image and statistical approaches are needed to identify the pixels for a lost golf ball.

The range of the color space is based at least in part on the color spaces identified for the type of object, such as a golf ball having a blue enhanced white not naturally found in objects, under various lighting conditions in the environment where the type of object would be lost. The color spaces for the object are defined by analyzing the color spaces obtained from the object in live color digital images of the object under the various lighting conditions in a training mode and storing the color spaces. The object is detected by using an algorithim that identifies pixels in the live color digital image that corresponds with a color space in the range of color spaces. Once a pixel is identified, it is recorded. Recorded pixels are analyzed to determine whether there are clusters of pixels that meet a particular criteria. The image may be filtered using polarization to eliminate glare.

BRIEF DESCRIPTION OF THE DRAWINGS

The above described features and advantages of the present invention will be more fully appreciated with reference to the detailed description and appended figures in which:

FIG. 1 depicts an exemplary functional block diagram of a device in which the present invention can find application; FIG. 2 depicts an exemplary color digital image taken with the device depicted in FIG. 1;

FIG. 3 depicts an exemplary flow diagram for detecting the location of an object in an environment according to an embodiment of the present invention; and

FIGS. 4a-4d depict exemplary color space diagrams of an object shown in a color digital image.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is now described more fully hereinafter with reference to the accompanying drawings that show embodiments of the present invention. The present invention, however, may be embodied in many different forms and should not be construed as limited to embodiments set forth herein. Appropriately, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention.

According to embodiments of the present invention, a method, a device and a computer program product for determining the location of an object in an environment are provided. The method receives an optical image of an environment and converts the optical image of the environment into a live color digital image of the environment consisting of charged signals, where each charged signal was generated by a pixel in an array of a Charged Coupler Device (CCD) by photoelectric conversion.

The live color digital image depicts an environment having one or more similar objects. Software performs an analysis of the live color digital image to detect and determine the location of the one or more objects in the live color digital image of the environment by using color and shape characteristics of the one or more objects. The software uses a range of the visible portion of the color space uniquely identified for the type of object in that environment to detect and determine the location of the one or more objects in the live color digital image of the environment. When the object is a golf ball, color is defined by reflection of light and by UV stimulated emission of blue fluorescence due to the brighteners incorporated in the composition of golf balls. Color in this application may be due to the reflection of light, stimulated emission such as fluorescence, phosphorescence and alike processes separately or in combination. In the presence of sufficient sun light, the color of a golf ball is expected to be unique, a blue enhanced white not naturally found in objects. Furthermore, because a lost golf ball is only partially visible, where 1% or more of its surface may be unobstructed, the color of the golf ball is not identifiable as an object. In general, the image of a lost golf ball occupies a very small percentage of the image and statistical approaches are needed to identify the pixels for a lost golf ball.

The range of the color space is based at least in part on the color spaces identified for the type of object, such as a golf ball having a blue enhanced white not naturally found in objects, under various lighting conditions in the environment where the type of object would be lost. The color spaces for the object are defined by analyzing the color spaces obtained from the object in live color digital images of the object under the various lighting conditions in a training mode and storing the color spaces. The object is detected by using an algorithim that identifies pixels in the live color digital image that corresponds with a color space in the range of color spaces. Once a pixel is identified, it is recorded. Recorded pixels are analyzed to determine whether there are clusters of pixels that meet a particular criteria. The image may be filtered using polarization to eliminate glare.

FIG. 1 depicts a functional block diagram of an image taking device in which the present invention can find application. In the embodiment of FIG. 1, image taking device 100 can be implemented to detect the presence of an object in an area in an environment and determine the location of the object in the particular environment, such as a golf ball on a golf course. In the FIG. 1 embodiment, image taking device 100 is a system, such as a digital camera, digital video camera, or the like, but can be any apparatus that executes program instruction in accordance with the present invention. In an embodiment of the present invention, the image taking device 100 is hand-held. In an embodiment of the present invention, the image taking device 100 is mountable on a mobile object, such as a golf cart, aircraft, or automobile. In an embodiment of the present invention, the imaging device 100 is positioned at a fixed location, such as a position of the green of a hole on a golf course.

In the FIG. 1 embodiment of the present invention, the image taking device 100 includes a processor (CPU) 102, an input system 104, imaging circuitry 106, programmable gain amplifier (PGA) 108, analog-to-converter 110, memory 112, data 116, and display 118. In the FIG. 1 embodiment, the input system 104 is a digital image system. The input system 104 provides an interface for acquiring light reflected from an object, and by UV stimulated emission of blue fluorescence due to the brighteners incorporated in the composition of golf balls or light depicting an object. In an embodiment of the present invention, the light acquired by the input system can be used to form a live image of the object and a live environment. The input system 104 includes imaging optics that may be set to satisfy the Scheimpflug Condition and a charge-coupled device sensor having a plurality of pixels. In the Scheimpflug Condition, the object plane, the image plane, and the median plane all intersect at a common point through the lens. This condition has the effect that an object plain is mapped onto a non-parallel image plane. The advantage of this condition is the ability to focus on the ground where we expect the lost object (for example, a golf ball) to be located with significantly improved depth of focus.

The input system 104 is coupled to circuitry 106 and provides an analog image signal to the circuitry 106. The circuitry 106 samples the analog image signal and extracts the voltage that is proportional to the amount of light which fell on each pixel of the charge-coupled device sensor of the input system 104 using color components R (red), G (green) and B (blue). Programmable gain amplifier (PGA) 108 is coupled to circuitry 106, amplifies the voltages to the proper range and provides the voltages as input to analog-to-converter 110. Analog-to-digital converter (ADC) 110 is coupled to CPU 102 and converts the voltage to a digital code suitable for further digital signal processing by CPU 102. The CPU 102 is a microprocessor, such as an INTEL PENTIUM® or AMD® processor, but can be any processor that executes program instructions in order to carry out the functions of the present invention.

In the FIG. 1 embodiment, the memory 112 is coupled to CPU 102 and stores object detecting program 114 and data 116. The data 116 includes, but is not limited to, a live color digital image depicting a particular environment having one or more objects whose locations in the environment are desired to be determined, a set of color space ranges, where each color space range in the set of color space ranges is uniquely identified for a type of object, and the color space of one or more pixels of the live color digital image. In an embodiment of the present invention, the color space is a range of blue enhanced white not naturally found in objects. The blue enhanced white is defined by the reflection of light of the golf ball, by UV stimulated emission of blue fluorescence from the golf ball due to the brighteners incorporated in the composition of the golf ball or a combination.

In the FIG. 1 embodiment, the object detecting program 114 provides the functionality associated with detecting the presence of an object in an environment and determining the location of the object in the environment, such as a golf ball, in the live color digital image of an environment as executed by the CPU 102. The object detecting program 114 is designed to report the location of an object in the live color digital image, such as on a display 118.

FIG. 2 depicts an exemplary live color digital image taken with the device depicted in FIG. 1. In FIG. 2 the live color digital image 200 shows golf balls 202a-202d distributed on terrain with grass.

An exemplary flow diagram of an embodiment for determining the location of an object in a particular environment is shown in FIG. 3. FIG. 3 is best understood when read in combination with FIG. 1. As shown in FIG. 3, the process begins with step 300, in which a target color space for the type of object is defined based on the observed R, G, B levels in a series of reference live images of the object, such as a golf ball having a color of blue enhance white. The series of reference live images are taken several times under various conditions to determine a desirable target color space. This training produces slightly different color spaces. Using a set of reference live images increases the robustness of our approach relative to using just a single image. In the case of typical golf balls, this results in a “blue enhanced white” space. This space may be a restricted set from the universe of observed colors, such as the space of colors that together account for 50% of all observations. The color space uses two of the three available degrees of freedom in the RGB measurement.

The target color space for a lost golf ball depends on both light reflected from the golf ball and light emitted from the golf ball, i.e., fluorescence of the golf ball. The fluorescence is due to brighteners added to golf ball to improve their appearance. Such brighteners absorb UV from sunlight and re-emit the light at lower energy as blue light. Blue color added to white is well known to improve the “whiteness” of an object. The practice of adding brighteners to golf ball is common for this reason. Hence, the color of a golf ball has two components, reflected light and blue fluorescence.

In defining a target color space, color shifts caused by the specific lighting conditions of the particular type of object must be considered and included in the target color space for the type of object. Accordingly, the color shifts of the type of object must be determined. This includes color shifts caused by “global” lighting, such as sunny versus cloudy weather, as well as “local” lighting, such as in grass or under a bush. For purposes of our invention, we define “white” as the color of a typical golf ball.

Turning here briefly to FIG. 4a-4d, where an exemplary color space diagram depicts the corresponding color space of a ball in a color digital image. In the FIG. 4 embodiment, the color space diagram 4b shows colors that in the picture 4a are provided in a shade of gray. The shade level gives an indication of the relative frequency of that particular color, with dark gray having few occurrences and white having many occurrences. This is due to the different color temperatures of the illumination. An automatic white balance feature to correct for color shifts may be provided on device 100 where the user can optionally select its operation. In the FIG. 4c embodiment, a subset of the color space of FIG. 4b is shown where only the colors that constitute 99% of the pixels are selected and represented in white by FIG. 4d. In the FIG. 4d embodiment, a subset of the color space of FIG. 4b is shown where only the colors that constitute 50% of the pixels are selected and represented in white by FIG. 4d.

Returning here to FIG. 3, in step 302 a live digital color image of an environment where the object is thought to be located is generated. This includes, but is not limited to, acquiring object light or light depicting an object and forming an image, providing an analog image signal for extraction of voltage which is proportional to the amount of light which fell on each pixel of a charge-coupled device sensor using color components R, G, and B, and converting the voltage to a digital code suitable for further digital signal processing. In an embodiment of the present invention, a light source may be used to shift the color space back into a regular detection range and to raise the light intensity from a ball resting in a shadow back up to the high levels expected if it was not shaded. One having ordinary skill in the art would understand that the light source can be a UV light source where device 100 employs UV color space. For the reasons cited, UV lighting particular where the ambient lighting was poor, such as in shaded areas or with overcast, will improve detection of a golf ball by stimulating fluorescence and the emission of blue light

In step 304, the digital color image is processed to detect the location of the object in the environment. This includes, but is not limited to, identifying pixels in the live color digital image that matches a color space in the target color space defined for the type of object. In the FIG. 3 embodiment of the present invention, the processing is performed by an algorithm that looks for blue and red pixels that fall into a color space in the target color space. All the pixels that fall into a color space in the target color space are then evaluated based on the pixels total luminance. Pixels that meet a minimum luminance value based on the current lighting conditions are then grouped into clusters of pixels that are all within a specific distance from each other. Each cluster is evaluated to determine if it meets certain color and luminance requirements to be a golf ball. If it does not then the cluster is rejected, otherwise the cluster is accepted as a possible location. The accepted clusters are sorted based on the most blue, least red, and brightest cluster in the image data, and storing the location of the pixels whose color space matches a color space in the defined target color space for the type of object.

In step 306, a decision statistic is defined that represents the likely characteristics of the type of object. In an embodiment of the present invention, the intensity of the background can be used as a decision statistic. The intensity of the background can be determined by processing the color digital image a second time. With an image-specific histogram of the background intensity, a lower-bound threshold for the expected target intensity can be defined, such as at the 90%, 95%, or 99% level of the background intensity. The pixels whose locations are stored can be screened using this criterion, with those pixels not meeting the intensity specification removed.

In an embodiment of the present invention, the size of the type of object can be used as a decision statistic. The size of the type of object can be used to identify the object by determining the diameter, such as a golf ball measured in pixels. This value can serve as a cluster distance. The pixels whose locations are stored can be screened using this criterion by collecting into groups, or clusters, those pixels that are within a cluster distance of each other.

In step 308, it is determined whether the object is identified in the environment based on one or more statistics. A statistic includes color space information, and may also include intensity information and/or cluster information. A statistic may also include weighting values from any reference images collected. The preferred approach is to define one statistic, but it is obvious that multiple statistics could be defined and used with this method. In step 310, the object is reported if identified, such as by display 118.

While specific embodiments of the present invention have been illustrated and described, it will be understood by those having ordinary skill in the art that changes can be made to those embodiments without departing from the spirit and scope of the invention. For example, while the present invention concentrates on a single color digital image and stationary lost object analysis, it is understood that information from a series of images, a moving object or a specific object might advantageously be used as well. Also, while our application to golf balls has us discussing UV and visible light, the method is not dependent on this choice.

Claims

1. A method of determining the location of at least a portion of a stationary object in an environment, the method comprising:

defining a target color space for the object type of the stationary object, wherein the target color space is defined by reflected light and emmited light observed in a series of reference live digital color images of the object type;

detecting the presence of an object having a color space in the target color space; and

reporting the determination that there are a set of pixels within the target color space defined for the type of object that is stationary.

2. The method according to claim 1, wherein the color digital image is generated by one of: a digital camera and a digital video camera.

3. The method according to claim 2, further comprising providing a light source for illuminating the environment.

4. The method according to claim 1, wherein the object is white or any acceptable color for which RGB components may be determined.

5. The method according to claim 4, wherein the stationary object is a golf ball.

6. The method according to claim 5, wherein the environment includes at least one of: grass, bushes, trees, and sand.

7. The method according to claim 1, further comprising determining whether the set of pixels determined are within the target color space defined for the type of the stationary object satisfy a characteristic of the object.

8. The method according to claim 8, wherein the characteristic is one of: a size, color intensity and a shape.

9. The method according to claim 1, wherein defining the target color space includes generating the series of reference digital color images of the object type.

10. The method according to claim 1, further comprising storing the target color space.

11. The method of claim 1, wherein the live digital color image of the environment is one digital color image in a series of digital color images of the environment.

12. The method of claim 1, wherein the determination that there are a set of pixels within the target color space defined for the object type is reported by one of: a visual display, a tactile alert, a sound alert, and an odorous alert.

13. The method of claim 1, further comprising generating a live color digital image of the environment;

determining whether there are a set of pixels in the live digital color image of the environment that are within the target color space defined for the type of object that is stationary.

14. The method according to claim 13, further comprising reporting the location of the set of pixels in the live digital color image, wherein the set of pixels corresponds to the location of the at least a portion of the stationary of object in the environment.

15. An apparatus for determining the location of at least a portion of a stationary object in an environment comprising:

a processor operable to execute computer program instructions; and

a memory operable to store computer program instructions executable by the processor, for performing the steps of: defining a target color space for the object type of the stationary object, wherein the target color space is defined by reflected light and emmited light observed in a series of reference live digital color images of the object type; detecting the presence of an object having a color space in the target color space; and reporting the determination that there are a set of pixels within the target color space defined for the type of object that is stationary.

16. The apparatus according to claim 15, wherein the color digital image is generated by one of: a digital camera and a digital video camera.

17. The apparatus according to claim 16, further comprising means for providing a light source for illuminating the environment.

18. The apparatus according to claim 17, wherein the object is white or any acceptable color for which RGB components may be determined.

19. The apparatus according to claim 18, wherein the stationary object is a golf ball.

20. The apparatus according to claim 18, wherein the environment includes at least one of: grass, bushes, trees, and sand.

21. The apparatus according to claim 15, further comprising determining whether the set of pixels determined are within the target color space defined for the object type.

22. The apparatus according to claim 19, wherein the characteristic is one of: a size, color intensity and a shape.

23. The apparatus according to claim 15, wherein defining the target color space includes generating the series of reference digital color images of the type of object.

24. The apparatus according to claim 15, further comprising means for storing the target color space.

25. The apparatus of claim 15, wherein the digital color image is one digital color image in a series of digital color images.

26. The apparatus of claim 15, wherein the determination that there are a set of pixels within the target color space defined for the type of object is reported by one of: a visual display, a tactile alert, a sound alert, and an odorous alert.

27. The apparatus of claim 15, further comprising means for generating a live color digital image of the environment;

means for determining whether there are a set of pixels in the live digital color image of the environment that are within the target color space defined for the type of object that is stationary.

28. The apparatus according to claim 15, further comprising means for reporting the location of the set of pixels in the live digital color image, wherein the set of pixels corresponds to the location of the at least a portion of the stationary of object in the environment.