Patent Publication Number: US-2019178790-A1

Title: Object Illumination Systems

Description:
BACKGROUND 
     Objects undergo an inspection process prior to being used in order to ensure quality, aesthetics, and reduce a risk of failure. Objects of an aesthetic nature may be inspected for imperfections. Objects that are critical to an operation of a machine may be inspected for imperfections and defects to reduce or eliminate failure of the objects during the operation of the machine. 
     SUMMARY 
     An apparatus that may include a light guide. The light guide may include a body configured to direct at least a portion of light within a defined wavelength spectrum from a first light source toward an object. The body may be formed of a material to provide a threshold contrast ratio between a first portion of the object and a second portion of the object. The body may include a first surface that includes a cavity formed to receive at least a portion of an incident end the light source. The body may include a second surface at a distal end from the light source. The second surface may be a peripheral diffusing portion or a peripheral focusing portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present description will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the present embodiment, which, however, should not be taken to limit the present embodiment to the specific embodiments, but are for explanation and understanding only. 
         FIG. 1  shows an object illumination system, according to an embodiment. 
         FIG. 2A  shows the object illumination system in  FIG. 1  with a light guide, according to an embodiment. 
         FIG. 2B  shows the object illumination system in  FIG. 1  with an absorber, according to an embodiment. 
         FIG. 2C  shows the object illumination system in  FIG. 1  with the first light source and the first light guide, a second light source and a second light guide, and a third light source and a third light guide, according to an embodiment. 
         FIG. 2D  shows the object illumination system in  FIG. 1  with the light source and the light guide located below the object, according to an embodiment. 
         FIG. 2E  shows the object illumination system in  FIG. 1  with the light guide located below the object and the light elements on the bottom edges of the object, according to an embodiment. 
         FIG. 2F  shows the object illumination system in  FIG. 1  with a light guide located above the object and the light elements on the sides edges of the object, according to an embodiment. 
         FIG. 3A  shows the object illumination system in  FIG. 1  with the light source and the light guide located within the object, according to an embodiment. 
         FIG. 3B  shows the object illumination system in  FIG. 1  with the first light source and the first light guide located within the object and a second light source and a second light guide exterior to the object, according to an embodiment. 
         FIG. 3C  shows the object illumination system in  FIG. 1  with a conical mirror, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed object illumination systems will become better understood through a review of the following detailed description in conjunction with the figures. The detailed description and figures provide merely examples of the various embodiments described herein. Those skilled in the art will understand that the disclosed examples may be varied, modified, and altered without departing from the scope of the embodiments described herein. Many variations are contemplated for different applications and design considerations; however, for the sake of brevity, each and every contemplated variation is not individually described in the following detailed description 
     Throughout the following detailed description, examples of various object illumination systems are provided. Related features in the examples may be identical, similar, or dissimilar in different examples. For the sake of brevity, related features will not be redundantly explained in each example. Instead, the use of related feature names will cue the reader that the feature with a related feature name may be similar to the related feature in an example explained previously. Features specific to a given example will be described in that particular example. The reader should understand that a given feature need not be the same or similar to the specific portrayal of a related feature in any given figure or example. 
     Objects used for various applications may undergo an inspection process prior to being used. For example, objects of an aesthetic nature may be inspected for imperfections to ensure quality control of the objects. Objects that are critical to an operation of a machine may be inspected for imperfections and defects to reduce or eliminate failure of the objects during the operation of the machine. Objects that are joined together by welding or bonding may be inspected to verify the integrity of the weld and the objects after the welding or bonding process. 
     There are various processes to inspect the objects. In one example, an individual may visually inspect the object to identify surface imperfections in the object. In another example, an optical system may employ an light sensor to capture image data of the object and inspect the object using a software analysis program. An accuracy of the inspection of the object may vary based on environmental conditions. For example, the lighting conditions of the environment where the object is inspected may cause the accuracy of the inspection of the object to vary. When the lighting level is low, imperfections in the object may not be visible. When the light level is bright, imperfections in the object may be washed out by the light. 
     The radiation pattern of the light may also vary the inspection accuracy of the object. For example, when the light unevenly illuminates surfaces of the object, such as concave or convex surfaces, the imperfections of the object may not be visible or identified. Additionally, as the size and shape of the object varies, the accuracy of the inspection of the object may also vary. The variability of the accuracy of the inspection of the objects may lead to increased imperfections and failures of objects that were approved during inspections. 
     The embodiments described herein may address the above-noted deficiencies by providing an object illumination system to increase the accuracy of the inspections. The object illumination system may include a light guide to direct light from a light source and illuminate an object with light at a desired level. In one example, the light guide may diffuse or disperse light from a light source to evenly illuminate the object or a portion of the object. In another example, the light guide may focus the light from the light source to illuminate a portion of the object. The light guide may increase the accuracy of the object inspection by reducing or eliminating variations in the environment and/or variations in the inspection caused by varying sizes or shapes of the objects. 
       FIG. 1  shows an object illumination system  100 , according to an embodiment. The object illumination system  100  may include a light source  102 , an object  104 , and an light sensor  108 . The light source  102  may include one or more lighting elements  110 . In one example, the lighting elements  110  may be incandescent light bulbs, halogen light bulbs, or fluorescent light bulbs. In another embodiment, the lighting elements  110  may be light emitting diodes (LEDs). The lighting elements  110  may radiate light at a defined wavelength or wavelength spectrum. In one embodiment, the light may be a low band ultraviolet light or a high band ultraviolet light with a wavelength spectrum ranging between 350 nanometers (nm) and 450 nm. In another embodiment, the light may be near-infrared light with a wavelength spectrum ranging between 750 nm and 1100 nm. In another embodiment, the light may be infrared light with a wavelength spectrum ranging between 1700 nm and 2000 nm. In another embodiment, the light may be a single wavelength of light, such as 1550 nm that is the wavelength of light absorbed by water 
     The light may emit light towards the object  104 . The object  104  may include a first portion  105  and a second portion  106 . In one example, the first portion  105  and/or the second portion  106  may reflect at least a portion of the light. In another example, the first portion  105  and/or the second portion  106  may absorb at least a portion of the light. 
     In one embodiment, the first portion  105  and/or the second portion  106  may be transmissive material. In another embodiment, the first portion  105  and/or the second portion  106  may be absorptive material. In one example, the first portion  105  may be transmissive material and the second portion  106  may be transmissive material. In another example, the first portion  105  may include transmissive material and the second portion  106  may be absorptive material. In another example, the first portion  105  may include absorptive material and the second portion  106  may be transmissive material. In another example, the first portion  105  may include absorptive material and the second portion  106  may be absorptive material. 
     In one embodiment, the first portion  105  may be joined to the second portion  106 . For example, the first portion  105  may be joined to the second portion  106  by laser welding, ultrasonic welding, gluing, solvent bonding, hot plate welding, infrared welding, and so forth. For example, laser welding may use a laser beam to provide a concentrated heat source to form narrow, deep welds and high welding rates between the first portion  105  and the second portion  106 . The laser welding may be used in high volume applications using automation, such as in the automotive industry. 
     The joining technique may form a joint  112  where the first portion  105  and the second portion  106  are joined together. In one example, the light source  102  may illuminate the joint  112  for inspection. In another example, the illumination source  102  may illuminate at least a portion of the first portion  105  and/or the second portion  106  for inspection. 
     For example, the joint  112  or the first portion  105  or the second portion  106  may reflect at least a portion of the light from the light source  102  toward the light sensor  108 . The light sensor  108  may measure the amount of light reflected by the joint  112 , the first portion  105 , or the second portion  106 . In one example, the light sensor  108  may be a full spectrum light sensor that may measure light reflected across a full light spectrum. In another example, the light sensor  108  may measure a portion of light reflected within a light spectrum range. In another example, the light sensor  108  may be a still-image camera, a video camera, an infrared sensor, and so forth. 
     The light sensor  108  may be coupled to a processing device  114 . The light sensor  108  may send light measurement information to the processing device  114 . The processing device  114  may analyze the light measurement information to determine whether there may be any imperfections or defects in the joint  112 , the first portion  105 , or the second portion  106  of the object  104 . In one example, when the processing device  114  detects an imperfection or a defect in the object  104 , the processing device  114  may send an alert notification to a user, such as by displaying an alert on a display or user interface or communicating the notification to another device. In another example, when the processing device  114  does not detect an imperfection or a defect in the object  104 , the processing device  114  may send an approval notification to a user, such as by displaying an message on a display or user interface or communicating the notification to another device. 
     In one example, the processing device  114  may compare the light measurements with a predefined measurement to determine if the amount of light reflected by the object  104  is within an acceptable range that indicates there are not imperfections or defects. When the light measurements are within an acceptable range, the processing device  114  may send the approval notification. When the light measurements are not within the acceptable range, the processing device  114  may send the error notification. In another example, the processing device  114  may compare different portions of the joint  112 , the first portion  105 , and/or the second portion  106  to determine a contrast level between the different portions. When the contrast level is within an acceptable range, the processing device  114  may send the approval notification. When the contrast level is not within the acceptable range, the processing device  114  may send the error notification. 
       FIG. 2A  shows the object illumination system  100  in  FIG. 1  with a light guide  216 , according to an embodiment. Some of the features in  FIG. 2A  are the same or similar to some of the features in  FIG. 1  as noted by same reference numbers, unless expressly described otherwise. The light guide  216  may be configured to guide the light emitted from the light elements  110   a - c  in a desired direction or with a desired radiation pattern. In one example, the light guide  216  may be a diffuser to disperse or spread the light with a defined transmission pattern that is a light diffusion pattern. The light diffusion pattern spreads the light over a surface or surfaces of the object  104 . In another example, the light guide  216  may be a focuser that may focus the light with a defined transmission pattern that is a light focusing pattern. The light focusing pattern may focus the light to a single surface of the object  104  multiple surfaces of the object  104  or a portion of the object  104 . 
     In one embodiment, the light guide  216  may be located approximate to an end of the light elements  110   a - c  that transmit the light. For example, the light guide  216  may include a top surface  218  and a bottom surface  220 . The top surface  218  may be relatively flat or smooth and may be beneath the light elements  110   a - c  to direct the light transmitted from the light elements  110   a - c . In one example, there may be a space between the top surface  218  of the light guide  216  and the light transmitting end of the light elements  110   a - c . In another example, the top surface  218  of the light guide  216  may abut or be in contact with the light elements  110   a - c . The bottom surface  220  may be on a distal end of the light guide  216  that is on a side opposite the light elements  110   a - c . The bottom surface  220  may be a peripheral diffusing portion or a peripheral focusing portion of the light guide  216 . 
     In another embodiment, the light guide  216  may include cavities  222   a - c  to receive at least a portion of the light elements  110   a - c . For example, the cavity  222   a  may receive at least a portion of the light element  110   a,  the cavity  222   b  may receive at least a portion of the light element  110   b,  and the cavity  222   c  may receive at least a portion of the light element  110   c.  The portion of the light elements  110   a - c  may include a bulb portion of the light elements  110   a - c  or a light transmitting portion of the light elements  110   a - c . In another example, the cavities  222   a - c  may receive the entire light elements  110   a - c . The light guide  216  and the light source  102  may be a lighting device to illuminate the object  104 . 
     In one embodiment, the light guide  216  may include one or more materials to provide a threshold light contrast ratio at a desired area at the object  104 . For example, the light guide  216  may be a thermoset material, a thermoplastic resin, or a glass material that provides a threshold light contrast ratio at the joint  112  of the object  104 . In one example, the light contrast ratio may be an amount of light reflected by the joint  112  versus an amount of light reflected by the first portion  105  or the second portion  106  of the object. In another example, the light contrast ratio may be an amount of light reflected by the first portion  105  versus an amount of light reflected by the second portion  106  of the object. In another example, the light contrast ratio may be an amount of light reflected by a first part of the joint  112  versus an amount of light reflected by a second part of the joint  112 . In another example, the light contrast ratio may be an amount of light reflected by a first part of the first portion  105  versus an amount of light reflected by a second part of the first portion  105 . In another example, the light contrast ratio may be an amount of light reflected by a first part of the second portion  106  versus an amount of light reflected by a second part of the second portion  106 . 
     In one embodiment, the threshold for the light contrast ratio may be a threshold light contrast level for the light sensor  108  to distinguish between the different portions or parts of the object  104 . In another embodiment, the threshold for the light contrast ratio may be a threshold light contrast level for the light sensor  108  to distinguish between transmissive materials and absorbing materials of the object  104 . In another embodiment, the threshold for the light contrast ratio may be a threshold light contrast level for the light sensor  108  to distinguish between the normal material of the object  104  and imperfections or defects of the object  104 , as the imperfections or defects may absorb or reflect the light differently than the normal material of the object  104 . 
     In one embodiment, the light source  102  and the light guide  216  may be in contact with the object  104 . In another embodiment, the light source  102  and the light guide  216  may be a threshold distance from the object  104 . For example, the light source  102  and the light guide  216  may be a defined distance from the object  104  so as to illuminate a desired portion or part of the object  104 . In another embodiment, the object  104  may be on a first plane and the light source  102  and the light guide  216  may be coplanar or parallel to the first plane. In another embodiment, the object  104  may be on a first plane and the light source  102  and the light guide  216  may be on a second plane perpendicular to the first plane. In another embodiment, the object  104  may be on a first plane and the light source  102  and the light guide  216  may be on a second plane that is at an angle to the first plane. For example, the second plane may be at an angle to the first plane of 1 degree to 89 degrees. In another example, the second plane may be at a 45-degree angle or a 90-degree angle to the first plane. 
     The location and angle of the light source  102  and the light guide  216  relative to the object  104  is not intended to be limiting. In one example, the location and angle of the light source  102  and the light guide  216  relative to the object  104  may vary to illuminate different portions or pieces of the object  104 . In another example, the location and angle of the light source  102  and the light guide  216  relative to the object  104  may vary to adjust a contrast ratio between the portions or parts of the object  104 . 
     In one embodiment, the light guide  216  may allow a full spectrum of light to pass through the light guide  216  and be guided by the light guide  216 . In another embodiment, the light guide  216  may filter one or more wavelengths of light or a range of wavelengths of light to allow one or more wavelengths of light to pass through the light guide  216  and one or more wavelengths of light to be blocked by the light guide  216 . 
       FIG. 2B  shows the object illumination system  100  in  FIG. 1  with an absorber  224 , according to an embodiment. Some of the features in  FIG. 2B  are the same or similar to some of the features in  FIGS. 1 and 2A  as noted by same reference numbers, unless expressly described otherwise. In one example, the absorber  224  may be an absorbing compound that is doped or applied to the joint  112 , the first portion  105 , or the second portion  106  of the object  104 . In one example, the absorber  224  may be impregnated or added to the material of the joint  112 , the first portion  105 , or the second portion  106  of the object  104 . In another example, the absorber  224  may be applied to a surface of the joint  112 , the first portion  105 , or the second portion  106  of the object  104 . In another example, the absorber  224  may be applied to part of the joint  112 , the first portion  105 , or the second portion  106  of the object  104 . 
     In one embodiment, the absorber  224  may be applied to illuminate a part of the object  104 . The absorber  224  may increase or decrease a reflection level or absorption level of the part of the object  104  that the absorber  224  is applied to. In one example, the absorber  224  may be applied to the joint  112  to aid in illuminating the joint  112  or provide additional contrast at the joint  112  for the light sensor  108  to measure. In another embodiment, a first part of the first portion  105  may be joined to the second portion  106  using a first joining technique and a second part of the first portion  105  may be joined to the second portion  106  using a second joining technique. The absorber  224  may be applied to the second part to provide additional contrast for the joint  112  formed using the second joining technique. In one example, the first joining technique may be one of a laser welding technique, ultrasonic welding technique, gluing technique, solvent bonding technique, hot plate welding technique, IR welding technique, and so forth and the second joining technique may be another one of the laser welding technique, ultrasonic welding technique, gluing technique, solvent bonding technique, hot plate welding technique, IR welding technique, and so forth. 
       FIG. 2C  shows the object illumination system  100  in  FIG. 1  with the first light source  102  and the first light guide  216 , a second light source  226  and a second light guide  228 , and a third light source  230  and a third light guide  232 , according to an embodiment. Some of the features in  FIG. 2C  are the same or similar to some of the features in  FIGS. 1 and 2A-2B  as noted by same reference numbers, unless expressly described otherwise. 
     The object illumination system  100  may include multiple light sources and light guides. For example, the object illumination system  100  may include the first light source  102  and the first light guide  216  pair, the second light source  226  and the second light guide  228  pair, and the third light source  230  and the third light guide  232  pair to illuminate the object  104 . 
     In one embodiment, the first light source  102  and the first light guide  216  pair, the second light source  226  and the second light guide  228  pair, and the third light source  230  and the third light guide  232  pair may be located at different positions relative to the object  104 . In one example, the first light source  102  and the first light guide  216  pair, the second light source  226  and the second light guide  228  pair, and the third light source  230  and the third light guide  232  pair may each be located at different distances from the object  104 . In another example, the first light source  102  and the first light guide  216  pair, the second light source  226  and the second light guide  228  pair, and the third light source  230  and the third light guide  232  pair may each be located at different angles relative to the object  104 . In another embodiment, the first light source  102 , the second light source  226 , and/or the third light source  230  may transmit different wavelengths of light. For example, the first light source  102  may transmit light with a wavelength spectrum between 350 nanometers (nm) to 450 nm, the second light source  226  may transmit light with a wavelength spectrum between 750 nm to 1100 nm, and the third light source  230  may transmit light with a wavelength spectrum between 1700 nm to 2000 nm. The wavelength spectrums are not intended to be limiting. For example, the first light source  102 , the second light source  226  or the third light source  230  may transmit light with a wavelength spectrum between 1500 nm and 1600 nm. 
     In one embodiment, manual switches, firmware, integrated circuits, and so forth may control the light sources  102 ,  226 , and/or  230 . In another embodiment, the processing device  114  may control the light sources  102 ,  226 , and  230 . The processing device  114  may turn the light sources  102 ,  226 , and/or  230  on or off to illuminate different parts of the object  104  and/or to increase or decrease an amount of light that illuminates the object  104 . 
     In one example, the processing device  114  may turn the first light source  102  and the second light source  226  on to provide an increased illumination level of the object  104 . In another example, the processing device  114  may turn on the first light source  102 , the second light source  226 , and the third light source  230  at different times or in a sequential order to capture light measurements for light transmitted by the first light source  102 , the second light source  226 , and the third light source  230 , respectively. In another example, when the first light source  102 , the second light source  226 , and the third light source  230  transmit light at different wavelengths or wavelength spectrums or the first light guide  216 , the second light guide  228 , or the third light guide  232  filter transmitted light at different wavelengths, the processing device  114  may turn on the different light sources  102 ,  226 , and/or  230  based on the object  104  being illuminated. In one example, when the first portion  105  or the second portion  106  of the object  104  is a first material, the processing device  114  may turn on the first light source  102  to illuminate the object  104  at a first wavelength or wavelength spectrum. In another example, when the first portion  105  or the second portion  106  of the object  104  is a second material, the processing device  114  may turn on the second light source  226  or the third light source  230  to illuminate the object  104  at a second wavelength or wavelength spectrum. 
     In one embodiment, the processing device  114  may define a baseline measurement using a light measurement from one of the first light source  102 , the second light source  226 , or the third light source  230 . The processing device  114  may then take a second measurement from a different one of the first light source  102 , the second light source  226 , or the third light source  230  and compare the measurements to determine a variation between the light measurements. When the variation between the measurements exceeds a threshold, the processing device  114  may determine that the object  104  has an imperfection or defect. 
     When the light sensor  108  captures the various light measurements, the processing device  114  may analyze the light measurements to more accurately identify imperfections or defects. For example, when the first light source  102  illuminates the object  104  at a first distances, angle, or wavelength, the transmitted light may not fully illuminate the imperfections or defects of the object  104 , and when the second light source  226  illuminates the object  104  at a second distances, angle, or wavelength, the transmitted light may more fully illuminate the imperfections or defects of the object  104 . 
       FIG. 2D  shows the object illumination system  100  in  FIG. 1  with the light source  102  and the light guide  216  located below the object  104 , according to an embodiment. Some of the features in  FIG. 2D  are the same or similar to some of the features in  FIGS. 1 and 2A-2C  as noted by same reference numbers, unless expressly described otherwise. In one embodiment, the light source  102  and light guide  216  may illuminate the object  104  from below the object  104 . For example, the object  104  may be located between the light guide  216  and the light sensor  108 . In one example, the light elements  110  may be located approximate and below the object  104  and may transmit light through the bottom of the object  104  to the light sensor  108 . The light sensor  108  may measure an amount of light absorbed by different parts of the object  104 . 
       FIG. 2E  shows the object illumination system  100  in  FIG. 1  with the light guide  216  located below the object  104  and the light elements  110  on the edges of the light guide  216 , according to an embodiment. Some of the features in  FIG. 2E  are the same or similar to some of the features in  FIGS. 1 and 2A -D as noted by same reference numbers, unless expressly described otherwise. In one embodiment, the light source  102  and light guide  216  may illuminate the object  104  from the sides  229  and  230  of the object  104 . For example, the object  104  may be located between the light guide  216  and the light sensor  108 . In one example, the light elements  110  may be located below the object  104 , at the side of the light guide  216 , and approximate the sides  229  and  230  of the object  104 . The light elements  110  may transmit light to the sides  229  and  230  of object  104 . The object  104  may reflect at least a portion of the light to the light sensor  108 . The light sensor  108  may measure an amount of light reflected by different parts of the object  104 . 
       FIG. 2F  shows the object illumination system  100  in  FIG. 1  with a light guide  232  located above the object  104  and the light elements  110  approximate the sides  229  and  230  of the object  104 , according to an embodiment. Some of the features in  FIG. 2F  are the same or similar to some of the features in  FIGS. 1 and 2A -E as noted by same reference numbers, unless expressly described otherwise. In one embodiment, the light elements  110  may transmit light approximate the sides of the object  104  toward the light guide  232  located above the object  104 . In one example, the light guide  232  may have a conical shape, such as a conical mirror. In another example, the light guide  232  may have a dome shape that fits around a portion of the top of the object  104  and/or the sides  229  and  230  of the object  104 . The light guide may include a first portion  234  that may reflect the light from the light elements  110  toward the object  104 . The first portion  105 , the second portion  106 , or the joint  112  of the object  104  may reflect at least a portion of the light toward a second portion  236  of the light guide  232 . The first portion  234  of the light guide  232  may reflect the light from the light elements  110  to more fully illuminate at least a part of the object  104 . 
     The second portion  236  of the light guide  232  may be transmissive or translucent material and allow the light reflected from the object  104  to pass through the second portion  236  of the light guide  232  and reach the light sensor  108 . The light sensor  108  may measure the received light and the processing device  114  may analyze the measured light to identify imperfections or defects in the object  104 . The location of the light guide  232  is not intended to be limiting. In one example, the light guide  232  may be located below the object  104  or at a side of the object  104 . 
       FIG. 3A  shows the object illumination system  100  in  FIG. 1  with the light source  102  and the light guide  216  located within the object  104 , according to an embodiment. Some of the features in  FIG. 3A  are the same or similar to some of the features in  FIGS. 1 and 2A -F as noted by same reference numbers, unless expressly described otherwise. The object  104  may include a cavity  302 . The cavity  302  may be an empty space within the object  104 . The light source  102  and the light guide  216  may be shaped to fit within the cavity  302 . In one example, the light guide  216  may encapsulate the light source  102 . In another example, the light source  102  may fit within a cavity or opening of the light guide  216 . In another example, the light source and the light guide  216  may be located approximate the joint  112  or approximate a surface of the object  104 . 
     In one embodiment, when the light source  102  and the light guide  216  are located within the cavity of the object  104 , the light guide  216  may diffuse or focus the light from the light source  102  onto a portion of the first portion  105 , the second portion  106 , and/or the joint  112  of the object  104 . In another embodiment, when the light source  102  and the light guide  216  are located within the cavity  302  of the object  104 , the light guide  216  may diffuse the light from the light source  102  to substantially illuminate the entire object  104 . In one example, the object  104  may be cylinder shaped, square shaped, rectangular shaped, or another shape. The light sensor  108  may measure an amount of light transmitted through the object  104  for analysis by the processing device  114 . 
       FIG. 3B  shows the object illumination system  100  in  FIG. 1  with the first light source  102  and the first light guide  216  located within the object  104  and a second light source  304  and a second light guide  306  exterior to the object  104 , according to an embodiment. Some of the features in  FIG. 3B  are the same or similar to some of the features in  FIGS. 1, 2A -F, and  3 A as noted by same reference numbers, unless expressly described otherwise. 
     The object illumination system  100  may include multiple light sources and light guides located within the object  104  and/or exterior to the object  104 . For example, the first light source  102  and the first light guide  216  may be located within the cavity  302  of the object, as discussed above, to illuminate the object  104  from within the cavity  302 . The second light source  304  and the second light guide  306  may be located external to the object  104 , such as an exterior surface, and transmit light toward the object  104 . The light from the second light source  204  may be reflected off the first portion  105 , the second portion  106 , or the joint  112  of the object  104 . 
     In another embodiment, the first light source  102  and the second light source  304  may transmit different wavelengths of light. For example, the first light source  102  may transmit light with a wavelength spectrum between 350 nanometers (nm) to 450 nm and the second light source  304  may transmit light with a wavelength spectrum between 1500 nm to 1600 nm. The wavelength spectrums are not intended to be limiting. For example, the first light source  102  may transmit at 1550 nm, the wavelength absorbed by water, and the second light source  226  may transmit light at a wavelength between 1700 nm and 2100 nm. In another embodiment, the first light source  102  and the second light source  304  may transmit light at the same or similar wavelength spectrums and the first light guide  216  and the second light guide  306  may filter different wavelengths of light such that light emitted from the first light guide  216  and the second light guide  306  are different wavelengths of light. 
       FIG. 3C  shows the object illumination system  100  in  FIG. 1  with a conical mirror  308 , according to an embodiment. Some of the features in  FIG. 3C  are the same or similar to some of the features in  FIGS. 1, 2A -F, and  3 A- 3 B as noted by same reference numbers, unless expressly described otherwise. 
     The object illumination system  100  may include the light source  102  and the light guide  216  located within the cavity  302  of the object  104 , as in  FIG. 3B . In one embodiment, the light source  102 , the light guide  216 , and the object  104  may be located within a cavity  310  of the conical mirror  308 . The cavity  310  may be an indent, groove, or depression in the conical mirror  308 . In one example, the cavity  310  may be located at a center of middle of the conical mirror  308 . In one example, the conical mirror  308  may be a cone-shaped concave mirror. As light is emitted from the object  104  through the light guide  216  and the object  104 , the conical mirror  308  may reflect the light toward the light sensor  108 . The conical mirror may reflect the light to increase an amount of light received at the light sensor  108 . The increased amount of light received at the light sensor  108  may increase an accuracy of the light measurements used by the processing device  114  to detect imperfections and defects in the object  104 . 
     The disclosure above encompasses multiple distinct embodiments with independent utility. While each of these embodiments has been disclosed in a particular form, the specific embodiments disclosed and illustrated above are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the embodiments includes all novel and non-obvious combinations and sub-combinations of the various elements, features, functions and/or properties disclosed above and inherent to those skilled in the art pertaining to such embodiments. Where the disclosure or subsequently filed claims recite “a” element, “a first” element, or any such equivalent term, the disclosure or claims should be understood to incorporate one or more such elements, neither requiring nor excluding two or more such elements. 
     Applicant(s) reserves the right to submit claims directed to combinations and sub-combinations of the disclosed embodiments that are believed to be novel and non-obvious. Embodiments embodied in other combinations and sub-combinations of features, functions, elements and/or properties may be claimed through amendment of those claims or presentation of new claims in the present application or in a related application. Such amended or new claims, whether they are directed to the same embodiment or a different embodiment and whether they are different, broader, narrower or equal in scope to the original claims, are to be considered within the subject matter of the embodiments described herein.