A real-time monitoring method and system for light source life and uniformity

Abstract

The present invention provides a method and system for real-time monitoring of the life and uniformity of a light source. The present invention uses a semi-transparent and semi-reflective lens to divide the light emitted by the light source into two parts, one part of the light is reflected and enters the working area, and the other part of the light is transmitted out and then enters the Fresnel lens to converge the real image of the light source; the detection unit receives the real image of the light source after convergence by the Fresnel lens and takes a picture as an image, measures the real-time brightness of the real image and records it, and then compares the real-time brightness of the real image with the set brightness range of the real image. If the real-time brightness of the real image is lower than the set brightness range of the real image, voltage or current compensation is performed. If the voltage or current deviation is too large to be compensated, an alarm is issued to replace the lamp beads. The present invention ensures the consistency of the brightness of the entire light source, and only replaces the lamp beads when the voltage or current deviation is too large to be compensated. On the one hand, it avoids affecting the brightness and uniformity of the entire light source, and on the other hand, it extends the service life of the lamp beads and reduces replacement and maintenance costs.

Description

Technical Field

[0001] The present invention relates to the field of industrial automation detection, and in particular to a method and system for real-time monitoring of light source life and uniformity. Background Art

[0002] AOI automated inspection technology is being applied increasingly widely. In many applications, specialized light sources are used to illuminate the inspected object, and the inspection method is often to detect local features of the product illuminated by the illuminated light source. Therefore, the stability of the light source is a very important parameter. If the light source brightness is unstable, the inspection effect will be affected. In particular, modern industrial light sources are increasingly using LEDs as lighting. The consistency of LED aging and attenuation may not be completely consistent. Some LEDs may experience more or less brightness decrease than others. If the attenuation of some or one or two LEDs is too high or too low during use, it will cause uneven illumination of the area, leading to misjudgment in some AOI systems that are highly dependent on light source uniformity (for example, some applications designed to inspect flatness or uniformity). Therefore, uneven light source brightness attenuation is a major factor that reduces inspection results in some applications. Therefore, it is necessary to monitor the brightness attenuation uniformity of different light source areas to detect LED lights with inconsistent attenuation curves early and avoid economic losses caused by downtime. Summary of the Invention

[0003] To address the above-mentioned drawbacks, the present invention provides a real-time monitoring method and system for light source life and uniformity, which monitors the light source of AOI equipment, monitors the attenuation of the light source based on the attenuation rate of the light intensity signal, and reminds users to replace it on time.

[0004] In a first aspect, the present invention provides a method for real-time monitoring of light source life and uniformity, comprising the following steps:

[0005] 1) The semi-transparent and semi-reflective lens divides the light emitted by the light source into two parts. One part of the light is reflected and enters the working area, and the other part of the light is transmitted out and then enters the Fresnel lens to converge the real image of the light source;

[0006] 2) The detection unit receives the real image of the light source after being converged by the Fresnel lens and takes a photo of it, measures and records the real-time brightness of the real image, and then compares the real-time brightness of the real image with the set brightness range of the real image. If the real-time brightness of the real image falls within the set brightness range of the real image, monitoring continues; if the real-time brightness of the real image is lower than the set brightness range of the real image, voltage compensation is performed in time; when the voltage deviation reaches a threshold or the voltage cannot be compensated, an alarm is issued.

[0007] In one embodiment of the present invention, step 2) specifically includes the following process:

[0008] a. The detection unit takes the image and performs binarization. The light source projection area is selected and named as V1. An appropriate exposure time is selected and the image is binarized. The light source projection area is recorded as 1 and the non-light source area is recorded as 0.

[0009] b. Divide the projection image of the light source into i*j squares according to the arrangement of the lamp beads. Take the inscribed circle in each square and calculate the mean grayscale value of all pixels in the inscribed circle of the original image v1. The calculation formula is:

[0010] Among them, M is the mean grayscale value of the pixel inscribed circle of the original image V1, X1 to X k is the grayscale value of all imaging pixels within the inscribed circle, f1 to f x is the vertical distance between the pixel and the circumference;

[0011] c. Set the brightness and fluctuation range of each lamp area. The formula is: n ij =a ij ±x ij , where n ij Set the brightness range for each lamp area, a ij The original brightness of each lamp area, x ij The brightness fluctuation range of each lamp bead area;

[0012] d. The detection unit takes images at fixed intervals, repeats steps a to b, obtains the real-time brightness of each lamp bead area, and compares it with the set brightness range of the corresponding lamp bead area in step c. If the real-time brightness of a lamp bead area is lower than its corresponding set brightness range, voltage compensation is performed in time. If the real-time brightness of each lamp bead falls within its corresponding set brightness range after compensation, monitoring continues. If the set brightness range of the real image is not reached, the compensation voltage is continued to be increased according to the set voltage value. When the voltage deviation reaches the threshold or the voltage cannot be compensated, an alarm is issued.

[0013] In one embodiment of the present invention, the light sources are driven by the same initial operating voltage.

[0014] In one embodiment of the present invention, current compensation is used instead of voltage compensation.

[0015] In a second aspect, the present invention provides a real-time monitoring system for the life and uniformity of a light source, which includes: a semi-transparent and semi-reflective lens, which divides the light emitted by the light source into two parts, one part of the light is reflected and enters the working area, and the other part of the light is transmitted out; a Fresnel lens, which receives the light transmitted through the semi-transparent and semi-reflective lens and converges the real image of the light source; a detection unit, which receives the real image of the light source after convergence through the Fresnel lens, measures the real-time brightness of the real image and records it, and then compares the real-time brightness of the real image with the set brightness range of the real image. If the real-time brightness of the real image falls within the set brightness range of the real image, monitoring continues; if the real-time brightness of the real image is lower than the set brightness range of the real image, voltage compensation is performed in time. If the real-time brightness of each lamp bead falls within its corresponding set brightness range after compensation, monitoring continues; if the set brightness range of the real image is not reached, the compensation voltage is continuously increased according to the set voltage value. When the voltage deviation reaches a threshold or the voltage cannot be compensated, an alarm is issued.

[0016] In one embodiment of the present invention, the real-time brightness of the real image and the set brightness range of the real image are both geometrically converted based on the grayscale value of the image captured by the detection unit.

[0017] In one embodiment of the present invention, the light sources are driven by the same initial operating voltage.

[0018] In one embodiment of the present invention, the detection unit includes a camera sensor and a processor, the camera sensor is electrically connected to the processor, the camera sensor is used to receive the real image of the light source after being converged by the Fresnel lens and take a picture of it, and the processor is used to process the image.

[0019] In one embodiment of the present invention, current compensation is used instead of voltage compensation.

[0020] In summary, the present invention provides a method and system for real-time monitoring of light source life and uniformity. The present invention has the following beneficial effects: The present invention is used during routine maintenance operations of AOI equipment to monitor its light source, monitor the attenuation of the light source, and remind users to replace it on time, without affecting the performance of the AOI equipment or increasing any operational complexity.

[0021] Furthermore, by monitoring each lamp bead of the light source and performing voltage compensation in a timely manner, the brightness consistency of the entire light source is ensured. Lamp beads are replaced only when the voltage deviation is too large or the voltage cannot be compensated. On the one hand, this avoids affecting the brightness and uniformity of the entire light source, and on the other hand, it extends the service life of the lamp beads as much as possible and reduces replacement and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic structural diagram of a real-time monitoring system for light source life and uniformity provided in one embodiment of the present invention.

[0023] Figure 2 This is a flow chart of a method for real-time monitoring of light source life and uniformity provided by one embodiment of the present invention.

[0024] Explanation of the symbols of the main elements: 1. Light source; 2. Semi-transparent and semi-reflective lens; 3. Fresnel lens; 4. Detection unit; 5. Light mask; S1-S7, steps. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is sought, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Please refer to Figure 1 The embodiment provides a real-time monitoring system for light source life and uniformity, including a light source 1, a semi-transparent and semi-reflective lens 2, a Fresnel lens 3 and a detection unit 4.

[0027] Light source 1 is used to emit light for the AOI equipment. A transflective lens 2 is mounted within a light shield 5, forming an angle of 30°-75° with the light, preferably 45°. The transflective lens 2 splits the light emitted by light source 1 into two parts. One portion of the light is reflected, entering the work area and illuminating the product being inspected in the AOI equipment. The other portion of the light from light source 1 is transmitted out.

[0028] The Fresnel lens 3 is disposed on the other side of the light shield 5 relative to the light source 1 . The Fresnel lens 3 receives the light transmitted through the semi-transparent and semi-reflective lens 2 and converges the real image of the light source 1 at one point.

[0029] The detection unit 4 includes a camera sensor and a processor, which are electrically connected to the camera sensor. The camera sensor receives the real image of the light source 1 after being focused by the Fresnel lens 3, takes a picture, and transmits the image to the processor. The processor measures and records the real-time brightness of the real image, and then compares the real-time brightness of the real image with the set brightness range of the real image. If the real-time brightness of the real image falls within the set brightness range of the real image, monitoring continues; if it does not reach the set brightness range of the real image, the compensation voltage is increased according to the set voltage value. When the voltage deviation reaches the threshold or the voltage cannot be compensated, an alarm is issued to replace the light source 1.

[0030] Furthermore, the real-time brightness of the real image and the set brightness range of the real image are both geometrically converted based on the grayscale value of the image collected by the detection unit 4 .

[0031] In other embodiments, the real-time monitoring system for light source lifetime and uniformity performs current compensation on light source 1 instead of voltage compensation, which also falls within the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

[0032] Please refer to Figure 2 , an embodiment provides a method for real-time monitoring of light source life and uniformity, which includes the following steps:

[0033] Step S1: setting the initial operating voltage V0 of the light source 1.

[0034] Step S2: The semi-transparent and semi-reflective lens 2 is set at a fixed position of the lampshade, the power supply is driven with an initial working voltage V0, and the original brightness of each lamp bead of the light source 1 is recorded.

[0035] Specifically, in step S21, the semi-transparent and semi-reflective lens 2 divides the light emitted by the light source 1 into two parts. One part of the light is reflected and enters the working area, and the other part of the light is transmitted out and then enters the Fresnel lens 3 to converge the real image of the light source 1; the detection unit 4 receives the real image of the light source 1 after convergence by the Fresnel lens 3 and takes a photo of it, measures the original brightness of the real image and records it.

[0036] In step S22, the detection unit 4 takes the image and performs binarization, selects the light source projection area, takes the image and names it V1, selects a suitable exposure time, and binarizes the image, with the light source projection area being marked as 1 and the non-light source area being marked as 0;

[0037] Step S23: Divide the projection image of the light source into i*j squares according to the arrangement of the lamp beads. Take an inscribed circle in each square and calculate the mean grayscale value of all pixels in the inscribed circle of the original image V1. The calculation formula is:

[0038] Among them, M is the mean grayscale value of the pixel inscribed circle of the original image v1, X1 to X k is the grayscale value of all imaging pixels within the inscribed circle, f1 to f x is the vertical distance between the pixel and the circumference.

[0039] Step S3: Set the brightness and fluctuation range of each lamp bead area.

[0040] Specifically, for the normally working light source 1, set the brightness and fluctuation range of each lamp bead area. The formula is: n ij =a ij ±x ij , where n ij Set the brightness range for each lamp area, a ij The original brightness of each lamp area, x ij The brightness fluctuation range of each lamp bead area.

[0041] For example, according to the arrangement of the lamp beads, the light source projection area is divided into 8*8 squares, then n 11 =a 11 ±x 11 , n 12 =a 12 ±x 12 ,…n 88 =a 88 ±x 88 .

[0042] Step S4: When the light source 1 is in normal operation, the detection unit 4 takes images at fixed intervals and records the real-time brightness of each lamp bead area.

[0043] During normal operation of the light source 1 , the detection unit 4 takes images at fixed intervals, repeats steps S22 to S23 , and names the taken images V2 to Vn to obtain the real-time brightness of each lamp bead area.

[0044] Step S5: Compare the real-time brightness of each lamp bead area with the set brightness range of the corresponding lamp bead area to determine whether the real-time brightness of each lamp bead area falls within the set brightness range. If so, loop through step S4; if not, go to step S6.

[0045] Step S6: If the real-time brightness of a certain lamp bead area is lower than its corresponding set brightness range, increase the compensation voltage according to the set voltage value (for example, 0.01V each time), and then determine whether the real-time brightness of the corresponding lamp bead falls within its corresponding set brightness range. If so, continue monitoring; if not, go to step S7.

[0046] Step S7: Continue to increase the compensation voltage according to the set voltage value. When the voltage deviation reaches a threshold (for example, 1V) or the voltage cannot be compensated, an alarm is issued and the lamp beads are replaced.

[0047] In other embodiments, current compensation is performed on the light source instead of voltage compensation in the real-time monitoring method of light source life and uniformity, which also falls within the scope of protection of the present invention.

[0048] To sum up, the present invention monitors each lamp bead of the light source and performs voltage compensation in time to ensure the consistency of the brightness of the entire light source. The lamp bead is replaced only when the voltage deviation is too large or the voltage cannot be compensated. On the one hand, it avoids affecting the brightness and uniformity of the entire light source. On the other hand, it extends the service life of the lamp bead as much as possible and reduces replacement and maintenance costs.

[0049] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for real-time monitoring of light source life and uniformity, characterized in that: It includes the following steps: 1) The semi-transparent and semi-reflective lens divides the light emitted by the light source into two parts. One part of the light is reflected and enters the working area, and the other part of the light is transmitted out and then enters the Fresnel lens to converge the real image of the light source; 2) The detection unit receives the real image of the light source after being converged by the Fresnel lens and photographs it into an image, measures and records the real-time brightness of the real image, and then compares the real-time brightness of the real image with the set brightness range of the real image. If the real-time brightness of the real image falls within the set brightness range of the real image, monitoring continues; if the real-time brightness of the real image is lower than the set brightness range of the real image, voltage compensation is performed in a timely manner; when the voltage deviation reaches a threshold or the voltage cannot be compensated, an alarm is issued; The step 2) specifically includes the following process: a. The detection unit takes the image and performs binarization. The light source projection area is selected and named as V1. An appropriate exposure time is selected and the image is binarized. The light source projection area is recorded as 1 and the non-light source area is recorded as 0. b. Divide the projection image of the light source into i*j squares according to the arrangement of the lamp beads. Take the inscribed circle in each square and calculate the mean grayscale value of all pixels in the inscribed circle of the original image v1. The calculation formula is: Among them, M is the mean grayscale value of the pixel inscribed circle of the original image V1, X1 to X k is the grayscale value of all imaging pixels within the inscribed circle, f1 to f x is the vertical distance between the pixel and the circumference; c. Set the brightness and fluctuation range of each lamp area. The formula is: n ij =a ij ±x ij , where n ij Set the brightness range for each lamp area, a ij The original brightness of each lamp bead area, x ij The brightness fluctuation range of each lamp bead area; d. The detection unit takes images at fixed intervals and repeats steps a to b to obtain the real-time brightness of each lamp bead area, and compares it with the set brightness range of the corresponding lamp bead area in step c. When the real-time brightness of a lamp bead area is lower than the set range, the compensation is increased in increments of 0.01V according to the set voltage step until the voltage deviation reaches the 1V threshold or the voltage cannot be compensated, an alarm is issued, and the lamp bead is then replaced. The light sources are driven by the same initial operating voltage.

2. The method for real-time monitoring of light source life and uniformity according to claim 1, characterized in that: Current compensation is used instead of voltage compensation.

3. A system for real-time monitoring of light source lifetime and uniformity for implementing the method for real-time monitoring of light source lifetime and uniformity as claimed in claim 1 or 2, characterized in that: It includes: A semi-transparent and semi-reflective lens, which splits the light emitted by the light source into two parts, one part of the light is reflected and enters the working area, and the other part of the light is transmitted out; The Fresnel lens receives the light transmitted through the semi-transparent and semi-reflective lens and converges the real image of the light source; The detection unit receives the real image of the light source after being converged by the Fresnel lens, measures and records the real-time brightness of the real image, and then compares the real-time brightness of the real image with the set brightness range of the real image. If the real-time brightness of the real image falls within the set brightness range of the real image, monitoring continues; if the real-time brightness of the real image is lower than the set brightness range of the real image, voltage compensation is performed in time. If the real-time brightness of each lamp bead falls within its corresponding set brightness range after compensation, monitoring continues; if the set brightness range of the real image is not reached, the compensation voltage is continued to be increased according to the set voltage value. When the voltage deviation reaches the threshold or the voltage cannot be compensated, an alarm is issued.

4. The real-time monitoring system for light source life and uniformity according to claim 3, characterized in that: The real-time brightness of the real image and the set brightness range of the real image are both proportionally converted to the grayscale value of the image collected by the detection unit.

5. The real-time monitoring system for light source life and uniformity according to claim 3, characterized in that: The light sources are driven by the same initial operating voltage.

6. The real-time monitoring system for light source life and uniformity according to claim 3, characterized in that: The detection unit includes a camera sensor and a processor. The camera sensor is electrically connected to the processor. The camera sensor is used to receive the real image of the light source after being converged by the Fresnel lens and take a photo to form an image. The processor is used to process the image.

7. The real-time monitoring system for light source life and uniformity according to any one of claims 3 to 6, characterized in that: Current compensation is used instead of voltage compensation.

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