Adaptive lighting system and method for inspection of complex objects

Abstract

Illumination systems and methods of designing and construction of the same are disclosed. The resulting illumination systems comprising both Front and Back light modules, provides selectable and programmable illumination according to the requirements of the invention for optimal performance of enhancing defects on a multidimensional object. The light guides are suitably aligned to the Backlight module and mechanically integrated with spring loaded mechanisms to enable them to move freely and subsequently re-position them to a reference home position as determined at the time of setup of the illumination assembly. The Front light module is utilised to highlight surface defects and mechanically integrated to the illumination system. The illumination modules, may include multiple discrete light emitting components of different spatial intensity distribution and color spectrum mounted in specific layout such that the application oriented combined illuminating effect is created.

Description

[Technical Field]

[0001] This invention generally relates to an electronically controlled LED-based lighting system coupled to a light transmission guide to propagate light to hard-to-reach areas of multi-dimensional objects. This invention is particularly suitable for detecting multi-dimensional objects containing single-angle surfaces requiring special lighting and positioning techniques for enhanced detection. [Previous Technology]

[0002] If a conventional light source is designed to illuminate multiple surfaces, especially if the object has a single bevel, it is typically bulky and complex. In prior art patent US 8,100,552, the lighting device used a design with multiple light-emitting components mounted on a specific facet to conform to the object's contour. If the contour of the object to be detected changes, a new lighting module needs to be designed to achieve uniform illumination across the object, making the method complex, time-consuming, and uneconomical. Its inflexibility and lack of scalability make it difficult to expand and adapt to new types of objects with different surface contours.

[0003] Solid-state LEDs are generally used in various configurations to ensure that the light is evenly distributed across the object. However, such final configurations for a specific object may still have uneven illumination intensity across that area of ​​the object, leading to inconsistent and unreliable defect measurements. Furthermore, they are bulky and occupy valuable space within the detection system.

[0004] The current technology lacks an apparatus and method for uniformly illuminating the complex three-dimensional object without affecting the quality and accuracy of defect detection and related measurements. [Summary of the Invention]

[0005] This invention relates to an efficient and flexible lighting system comprising an illumination module suitably coupled to a set of planar, rectangular, or circular light guides made of acrylic or other light-transmitting material fitted with suitable retractable springs, and suitably positioned on a platform comprising at least two parallel plates allowing the light guides to move freely along their vertical axes. When the object to be inspected is positioned below a camera, it is positioned resting on the light guides, with one end of the light guides contacting the object and moving, adjusting, and positioning along the contour, while the other end is exposed to the backlighting module. With this configuration, when the backlighting is powered on, the light guides transmit light toward the object, thereby uniformly distributing the light at every point on the three-dimensional object. The camera captures multiple images of the object at different positions and angles for inspection. Upon completion of the inspection, the object is removed from the light guides, while the light guides return to their initial or reference positions.

[0006] The object is then illuminated from above using a top lighting module, and multiple images of different areas of the object are captured from different angles.

[0007] The camera can also be used by operators to inspect the surface of the illuminated object for the measurement of defects or features. Manual inspection or examination is generally employed during the setup and assembly of the inspection system.

[0008] One of the main advantages of this configuration is that it allows the lighting modules to be easily adapted to a variety of complex objects with three-dimensional features or defects on their surfaces. This flexible adaptability of the moving light guide, combined with the programmability of the lighting system, makes the lighting system very flexible and expandable, thereby enabling rapid reconfiguration of the lighting setup during product transitions.

[0009] Another advantage of the present invention is the reliability of illuminating the single inclined surface of the object, which is impossible in the present technology. When the object is properly tilted using an integrated motor coupled to the detection component, the features of the single inclined surface can also be reliably detected, thus the optimal view is presented to the camera.

[0010] Another advantage of the present invention is that the positioning of the backlight module can be achieved using a cylinder mechanically coupled to the backlight module. The enhanced image of the object captured by the camera under multiple illumination conditions makes it possible to measure more obvious fine defects and features.

[0011] Other embodiments of the present invention include various combinations of one or more of the embodiments described above, as well as combinations of one or more specific embodiments as known in or likely to be derived therefrom. It should also be understood that other specific embodiments of the present invention can be derived by those skilled in the art from the following specific embodiments of the present invention.

Implementation Method

[0013] In the following preferred embodiments of the invention, reference will be made to the accompanying drawings, which form a part therein, and are shown by way of illustrating specific embodiments in which the invention may be practiced. It should be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention.

[0014] Figure 1 shows a first embodiment of one of the systems and methods according to the present invention. System 100 schematically illustrates a first embodiment of the present invention, which is an apparatus for detecting defects in a complex three-dimensional object including its single bevel. Defects such as the size of holes, imprints on its surface, molding features, scratches, contaminants, and the absence and presence of all edge defects around the object can be measured.

[0015] The first specific embodiment 100 in Figure 1 includes a high-resolution camera 30 mounted on an XY motor drive platform 25 (motor not shown); at least two illumination sources; a ring lamp or top lamp 22; and a planar LED backlight 8. The backlight 8 is mechanically and optically coupled to a set of light guides 10, preferably an array of light transmission elements made of an effective light-dispersing material. The light guide assembly is designed with two metal plates 18 and 20 drilled with identical and symmetrical holes. Each aligned hole in plates 18 and 20 is configured to hold spring-loaded units 12 and 14 respectively, and the set of light guides 10 is mounted and held on a positioning P1 at a starting or reference position that can be adjusted according to the application via the spring-loaded units 12 and 14. The number of light guides 10 used is determined by the application. The set of light guides 10 can be vertically moved via the mechanism of a set of spring-loaded bearings 12 and 14. The light guides 10 can be made of acrylic resin, polycarbonate, or similar materials with high dispersion properties to illuminate the object around the single bevel and uneven surfaces at different positions and depths. The light guides 10 can also be designed with different angles, thicknesses, or profiles to accommodate different types of objects, thereby making them expandable and cost-effective.

[0016] When the backlight accessory assembly 102 moves to position P2 in the vertical direction 16, the light guide 10 is appropriately positioned to obtain the contour of the top surface of the object 50. The backlight accessory assembly 102 includes elements 8, 10, 12, 14, 18, and 20, which are mechanically integrated together and driven by a motor (not shown). The motor drives the backlight illumination module to move vertically between positions P1 and P2 shown in FIG. 1.

[0017] Those skilled in the art know that several different vertical positions can be programmed to suit different types of object contours. The separate front lighting module 22 is adapted to be coupled to another motor (not shown) so that it can be positioned at different locations below the object. The backlighting module 8 and the front lighting module 22 are manufactured using a segmented design, which uses LEDs of different wavelengths and is electronically coupled to a strober (not shown) that is programmed to trigger the illumination at different time intervals (with different pulse durations, different intensities, and different spectra for enhancing the defect characteristics of the object 50) and to facilitate image capture under different lighting conditions.

[0018] Figures 2 and 3 illustrate the top and bottom views of the general object 50, respectively. Clearly, the object 50 has multiple three-dimensional profiles and may be porous or contain cutouts, suitable for specific applications. It may also include various single bevels around the object.

[0019] Figure 4 illustrates the detection technique of this first embodiment of the present invention for detecting defects on an object 50. In this technique, the backlight illumination accessory assembly 102 is moved downward to positioning P2, while the light guide 10 is moved to contact the top surface of the object 50. A magnified image of the box B1 in Figure 4 is shown in Figure 4b. The movement of the light guide 10 is clearly visible in Figure 4b.

[0020] As previously described, the backlight 8 is made of LEDs and can illuminate each light guide segmentally, individually or simultaneously, thereby allowing for a highly complex lighting control mechanism. At position P2 in Figure 4, the backlight 8 and camera 30 are triggered or strobed to illuminate the group of light guides 10 and simultaneously capture an image of the area of ​​the object 50 to be observed, as illustrated in Figure 4a. Subsequently, the XY-axis slide 25 moves from one area to the next until the surface area of ​​the object has been imaged by the camera 30. Then, these images are appropriately combined to obtain a complete image of the object 50 for further analysis and classification. Subsequently, the results of the detection are communicated via an external interface for segregation and sorting.

[0021] Figure 5 illustrates the detection technique of the present invention for detecting defects on the bottom surface of an object 50. In this technique, the backlight illumination assembly 102 is moved upward to the reference position P1, while the light guide 10 is moved away from the top surface of the object 50 by means of the spring-loaded bearings 12 and 14. At position P1, the backlight 8 is turned off and the ring lamp 22 is turned on to illuminate the bottom surface of the object 50. The ring lamp 22 and the camera 30 are triggered or flashed to illuminate the bottom surface and simultaneously capture an image of the area of ​​the object 50 to be observed, as illustrated in Figure 5a. Subsequently, the XY-axis slide 25 moves from one area to the next until the surface area of ​​the object has been imaged by the camera 30. Then, the images are appropriately combined to obtain a complete image of the object 50 for further analysis and classification. Subsequently, the results of the test are communicated through an external interface for separation and classification.

[0022] Figure 6 illustrates the detection technique in a second embodiment of the present invention for detecting defects on object 50. In this embodiment 110, the backlight illumination accessory assembly 102 is the same as in Figure 1, but the light guides 10 are mounted facing upwards. The backlight illumination accessory assembly 102 further includes a pair of cylinders 40 and 42, which are mechanically mounted on plates 18 and 20 to drive the backlight source 8 up and down. It is further coupled to another motor 39. The backlight illumination accessory assembly 102 is further mounted on another mechanism suitable for coupling to another motor 37. Motors 39 and 37 are capable of moving 110 on two different axes. Motor 39 is used to rotate 110 with object 50 on rotation axis 44, and motor 37 is used to move 110 with object 50 on rotation axis 40. The provided set of cylinders 40 and 42 enables the backlight source 8 to be vertically moved between two or more programmable positions. Cylinders 40 and 42 are also used to move the light guide 10 to the position determined by the software program. The ring light 22 in Figure 6 illuminates the top surface of the object 50, and the backlight 8 illuminates the bottom surface of the object 50 through the light guide 10. A camera 30 mounted on the XY-axis slide 25 is positioned to capture an image of the top surface of the object 50 in Figure 6.

[0023] The first procedure step of the detection method in the second embodiment shown in FIG. 7 begins with the object 50 moving downward from positioning P3 toward positioning P4 towards the light guides 10. The light guides 10 position themselves at their respective points on the bottom surface of the three-dimensional object 50. As previously mentioned, the light guides 10 are integrated into the plates 20 and 18 via spring-loaded guide units 12 and 14, respectively, thereby allowing them to move freely along the vertical axis. After the object 50 is positioned at the predetermined position P4 as shown in FIG. 7, when the camera 30 is synchronized with the ring light 22 for illumination, it captures an image of the predetermined area to be observed on the top surface of the object 50. The image of the general area to be observed is illustrated in FIG. 7a, in which the symbols printed on the surface of the object 50 are enhanced. Subsequently, the XY-axis slide 25 moves from one area to the next until the surface area of ​​the object has been imaged by the camera 30. These images are then appropriately combined to obtain a complete image of the object 50 for further analysis and classification. The detection results are then communicated via an external interface for separation and classification.

[0024] The ring lamp 22 in Figure 7 is mechanically integrated into the XY axis slide 25 and is properly positioned and flashed during image capture to enhance the surface scratches, stains, symbols, marks and other defects on the object 50.

[0025] In the second procedure step shown in Figure 8, the ring light is turned off and the backlight 8 is flashed to allow the camera 30 to capture an image of the area of ​​the object 50 to be observed. An image of the general area to be observed is illustrated in Figure 8a, where symbols printed on the object 50 are clearly visible along with perforations or holes. The captured image illuminated by the backlight 8 helps detect missing holes, damaged holes, incorrectly sized holes, and other defects visible in the backlit image. Subsequently, the XY-axis slide 25 moves from one area to the next until the surface area of ​​the object has been imaged by the camera 30. The images are then appropriately combined to obtain a complete image of the object 50 for further analysis and classification. The results of the detection are then communicated via an external interface for separation and classification.

[0026] The third procedure of the detection method in the second embodiment is shown in FIG. 9. It begins with the object 50 moving downward from positioning P3 to positioning P4 towards the light guides 10, as shown in FIG. 7. After the object 50 is positioned at the predetermined position P4 as shown in FIG. 7, the motor 37 rotates to a pre-programmed angle to present the raised and single-sloped side of the object 50 to the camera 30. The camera 30 captures the image of the predetermined area of ​​the object 50 to be observed, while simultaneously flashing the top light or ring light 22 for illumination. The image of the general area to be observed is illustrated in FIG. 9a, in which the surface features at the single-sloped surfaces of the raised structures on the object 50 are enhanced. The ring light 22, also integrated into the XY axis slide 25, is appropriately positioned and flashed to enhance surface scratches, stains, symbols, and other defects on the object 50. In the next step, motor 39, as programmed by the software, rotates and positions object 50 to the next area to be observed. This process continues until the entire area of ​​object 50 is imaged. These images are then appropriately combined to obtain a complete image of the relevant single-slope surface of object 50 for further analysis and classification. Subsequently, the results of the detection are communicated via an external interface for separation and classification.

[0027] A fourth procedure step includes repositioning the object 50 at a different pre-programmed angle by means of a rotary motor 37, and repeating the entire third procedure again until all such pre-programmed angles have been executed.

[0028] In the fifth procedure step shown in Figure 10, the ring light is turned off while the backlight 8 is turned on or flashed. After the object 50 is positioned at the predetermined position P4 as shown in Figure 7, the camera 30 captures the image of the predetermined area of ​​the object 50 to be observed, and simultaneously flashes the backlight 8 for illumination.

[0029] Figure 10a illustrates an image of the general area to be observed, in which the perforations located on the single inclined plane of object 50 are clearly visible. The procedure continues until the entire area of ​​object 50 is imaged. Then, these images are appropriately combined to obtain a complete image of the relevant single inclined plane of object 50 for further analysis and classification. Subsequently, the detection results are communicated via an external interface for separation and classification.

[0030] The images captured in the fifth procedure step help to detect missing holes, damaged holes, incorrectly sized holes, and other defects visible in the backlit images of the single bevel of the object 50.

[0031] In the sixth procedure step using backlight 8 illumination, the XY-axis slide, as programmed by the software, moves from one area to the next to be observed. Subsequently, motor 39 rotates to position object 50 at different points around it for image acquisition using backlight illumination. The procedure continues until the entire area of ​​object 50 is imaged using single-slope planes. These images are then appropriately combined to obtain a complete image of the relevant single-slope plane of object 50 for further analysis and classification. The results of the detection are then communicated via an external interface for separation and classification.

[0032] Those skilled in this technology can change the angle of the object and modify the lighting sequence and characteristics such as intensity, wavelength and flash pulse duration, and also use segmented lighting to highlight different features on the surface of the object 50.

[0033] Figure 11 is an example diagram showing how to achieve enhanced imprints and surface defects (such as 56 and 54 and 55) on the surface of a top or ring lamp.

[0034] Figure 12 is an example diagram showing how to achieve enhanced perforations (such as 58 and 60) on a backlit surface. It is clear that, apart from detecting missing perforations 52 or inaccurately spaced perforations, the diameter of the perforation is easily and accurately measured in a backlit image.

[0035] Several specific embodiments of the present invention have been described. Those skilled in the art should understand that the foregoing is merely illustrative and not limiting, and is presented only by way of example. Numerous modifications and other specific embodiments are within the scope of those skilled in the art, and are considered to be within the scope of the present invention as defined in the claims and equivalents herein. [Simplified Explanation of the Diagram]

[0012] The specific features, aspects, and advantages of the present invention will be better understood by the following embodiments, the accompanying claims, and the accompanying drawings, in which: FIG1 shows a system of all elements constituting a preferred embodiment of the present invention. FIG2 is an example view of the top surface of the three-dimensional object. FIG3 is an example view of the bottom surface of the three-dimensional object. FIG4 is an example view of one aspect of the preferred embodiment of the present invention. FIG4a is an image of the area of ​​the object with the backlight illumination turned on in FIG4. FIG4b is an unfolded view of the image area enclosed in FIG4. FIG5 is an example view of another aspect of the preferred embodiment of the present invention. FIG5a is an image of the area of ​​the object with the front light illumination turned on in FIG5. FIG6 shows a system of all elements constituting another embodiment of the present invention. The system is designed to rotate the object on two different axes so that the object can be detected at different angles using top light illumination or backlight illumination. FIG7 is an example view of the system showing the aspect of the embodiment in FIG6. Figure 7a illustrates an image of the top-lit area of ​​object 50 in Figure 7. Figure 8 is an illustration of another aspect of the system shown in Figure 6. Figure 8a illustrates an image of the backlit area of ​​object 50 in Figure 8. Figure 9 is an illustration of yet another aspect of the system shown in Figure 6. Figure 9a illustrates an image of the top-lit area of ​​the inclined surface of object 50 in Figure 9. Figure 10 is an illustration of yet another aspect of the system shown in Figure 6. Figure 10a illustrates an image of the backlit area of ​​the inclined surface of object 50 in Figure 10. Figure 11 shows an image of the top-lit area of ​​the object in Figure 2. Figure 12 shows an image of the backlit area of ​​the object in Figure 2.

Claims

1. An illumination system for substantially illuminating a multidimensional object with multiple perforations and a single bevel, for detecting defects such as foreign matter contamination, inaccurate perforation dimensions, defects in imprints, and damaged surfaces, the system comprising: a) a high-resolution camera for image capture, mounted on an XY-axis slide for positioning the camera at a predetermined position; b) an LED array mounted on a flat plate for backlighting, the LEDs being adapted to be segmented such that selected and pre-programmed sections can be illuminated by a strobe light to illuminate one end of a series of parallel-mounted acrylic-based light guides; c) a ring luminaire based on circular LEDs for front illumination, wherein the LEDs are adapted to be segmented such that selected and pre-programmed sections can be illuminated by a strobe light; d) a plurality of spring-loaded, telescopic light guides for propagating light, arranged parallel to each other on a pair of plates mechanically coupled to the backlighting; e) f) At least one pair of cylinder-based transfer mechanisms to move the backlight illumination to one or more predetermined positions; g) a first mounting system to rotate the backlight illumination assembly about the central axis of the camera and optical system; h) a second mounting system to rotate the backlight illumination assembly on an axis perpendicular to the first mounting system; i) an object positioning mechanism to suitably position the object to be detected at several predetermined positions; and d) a flash control system to control the duration of the trigger pulse and the illumination intensity.

2. The lighting system as claimed in claim 1, wherein the surface of the object to be detected comprises several types of cavities, holes, and single bevels, which are at unequal distances from the camera.

3. The lighting system as claimed in claim 1, wherein the ends of the light guides are mechanically integrated with a flat panel backlight.

4. The lighting system as claimed in claim 1, wherein the ring luminaire located on the opposite side of the backlight is used for top lighting.

5. The lighting system as claimed in claim 4, wherein the ring lamp is programmed by the user to illuminate the markings on the surface of the object to detect defects in the markings.

6. The lighting device as claimed in claim 1, wherein the backlight is segmented such that a programmable lighting system can perform selective segmented lighting, intensity control, and trigger pulse width control.

7. The lighting system as claimed in claim 1, wherein the retractable light guide system configured on at least two mounting plates is uniquely positioned to obtain the outline of the object to be detected, so as to enable substantially uniform illumination distribution.

8. A method for illuminating a multi-dimensional object with multiple perforations and a single bevel, for detecting defects such as the presence of foreign matter contamination, inaccurate dimensions of perforations, damaged surfaces, and defects in imprints, the procedure comprising: j) a positioning method for positioning the object to be inspected close to the light guides to ensure uniform illumination of all uneven surfaces; k) a programming method for simultaneously or alternately flashing the backlight and front light to enhance different features of the object at different angles; l) a set of cylinders mechanically integrated into the vertically movable backlight to emit light at one end of all the light guides for light propagation and illumination of the object being inspected at the other end; m) moving the set of cylinders mechanically integrated into the backlight to reset the light guides at a predetermined reference position after image acquisition; n) a movable front light ring lamp adapted to be integrated into the camera XY-axis slide for positioning at different locations to illuminate the area of ​​the object being inspected; o) A method for angular positioning, wherein the object is rotated to several preset positions determined during calibration, and the images of the entire area of ​​the object are captured at a high resolution; p) a method for operating a first motor to rotate the backlight illumination assembly around the central axis of the detection system; q) a method for operating a second motor to rotate the backlight illumination assembly on an axis perpendicular to the first backlight illumination system, thereby positioning the object at several single inclined planes of the object at an angle; r) a method for triggering the flash control system to control the duration of the trigger pulse, the selection of LED segments of the illumination, and the intensity; 9. The illumination method as described in claim 8, wherein the surface of the object to be detected comprises several types of cavities, multi-dimensional holes, and single bevels, which are at unequal distances from the camera.

10. The illumination method as claimed in claim 8, wherein the ends of the plurality of light guides are positioned on the surface of the object to illuminate a single bevel and an uneven surface to achieve uniform illumination across the entire detection area.

11. The lighting method as claimed in claim 8, wherein the lighting sources are selectively illuminated by LED segments to illuminate specific predetermined areas to detect defects in the imprint, the presence of foreign matter, abnormal perforations, and damaged surfaces.

12. The illumination method as claimed in claim 8, wherein the positioning method is programmed to uniquely align the object relative to the light guide array to enhance illumination of all predetermined surface areas, enabling the detection of defects in the imprint, the presence of foreign matter, abnormal perforations, and damaged surfaces.

Images