CN102322593B - Self-adaptive light source device and control method thereof - Google Patents

Abstract

The invention discloses an adaptive light source device, which comprises a hemispherical casing with a hole on the top, a bottom plate connected to the bottom of the hemispherical casing, and an arc-shaped light source group arranged on the bottom plate and distributed inside the bottom of the hemispherical casing. A guide sleeve is provided at the opening on the top of the hemispherical shell, and a light shield that can move up and down relative to the guide sleeve is arranged on the guide sleeve and inside the hemispherical shell. The light shield is connected to the power output end of the stepping motor connection, the inner surface of the hemispherical shell is evenly sprayed with high reflectivity diffuse reflection radiant material, and the control part of the stepping motor is electrically connected with the control system. The invention has self-adaptive function, and can obtain a clear and stable image by one imaging by automatically controlling the illuminance of the chamfered surface of the end face of the magnetic tile and the arc-shaped plane. The shape and size of the end face of the magnetic tile are diverse, and the degree of automation is high.

Description

An online automatic detection adaptive light source device and its control method for magnetic tiles

technical field

The invention relates to the technical field of mechanical engineering lighting, in particular to an adaptive light source device and a control method thereof.

Background technique

Due to its outstanding advantages of fast, efficient, accurate and reliable, and non-contact, machine vision inspection has become one of the main methods of industrial automation inspection. Especially for products with small profits per piece and mass production, machine vision inspection can realize non-sampling comprehensive real-time online inspection, which plays an important role in ensuring product quality, reducing labor intensity of workers, and improving production efficiency and economic benefits of enterprises.

In the machine vision inspection system, the light source and lighting are the key to the success of the current machine vision application system. A good lighting system should obtain high-quality images as much as possible, and highlight the features of the detection target as much as possible, so as to reduce the difficulty of image processing and improve the image processing speed.

The magnetic tile is the key component to generate the magnetic field in the permanent magnet motor, and its quality has a great influence on the performance of the permanent magnet motor. At present, my country is the largest producer of magnetic tiles. Magnetic tiles are typical single-piece small profits and mass-produced products. Due to the various types and specifications of magnetic tiles, the great difference in shape, the large number of detection surfaces, the fast production cycle, and the many types of defects in magnetic tiles, the online automatic detection method for magnetic tiles has not made substantial progress so far. Manufacturers of magnetic tiles still rely mainly on manual visual inspection. In general, machine vision systems are designed specifically for specific models of products, and there are specificities in light source configuration, algorithm design, mechanism design, etc., and are not suitable for a machine vision system to detect multiple products. An important reason that limits the progress of magnetic tile detection is that the light source lighting system is difficult to adapt to the diversity of magnetic tile shapes and sizes.

In the current literature discussion, a good solution has not been proposed, and no relevant discussion on the study of the magnetic tile adaptive light source has been retrieved. In the relevant solutions for magnetic tile detection, ready-made light sources are generally used for lighting, which does not have universal adaptability.

Contents of the invention

The object of the present invention is to solve the above-mentioned problems, to provide a suitable illumination source for the end face of the magnetic tile, so that it can obtain the chamfered surface and the arc plane of the end face of the magnetic tile in one imaging in the CCD camera. Reliable image to improve real-time online inspection speed, cost-reduced adaptive light source device and control method thereof.

The technical solution of the present invention is realized as follows: an on-line automatic detection adaptive light source device for magnetic tiles, characterized in that it includes a hemispherical shell with a hole on the top, a bottom plate connected to the bottom of the hemispherical shell, and a On the base plate, the arc-shaped light source group distributed on the inner side of the bottom of the hemispherical shell is provided with a guide sleeve at the opening on the top of the hemispherical shell. A shading plate that moves up and down, the shading plate is connected to the power output end of the stepping motor, and the inner surface of the hemispherical shell is evenly sprayed with a diffuse reflective light-emitting material with high reflectivity, and the control part of the stepping motor is connected with the Control system electrical connection;

The arc-shaped light source group is composed of a number of LED light sources that are independent of each other and evenly distributed inside the bottom of the hemispherical shell. The LED light source is connected to the output end of the power supply, and the power supply is electrically connected to the control system. The electronics of the LED light source The switches are respectively electrically connected with the control system.

The self-adaptive light source device for online automatic detection of magnetic tiles according to the present invention, the stepper motor is arranged above the hemispherical shell through the mounting plate, the power output end of the stepper motor is connected with a screw rod, the wire The rod passes through the hemispherical shell and is threadedly connected with the nut provided on the light shielding plate.

The self-adaptive light source device for online automatic detection of magnetic tiles according to the present invention is provided with a shading ring on the bottom plate and inside the arc light source group to prevent the light emitted by the light source from directly entering the lens.

The self-adaptive light source device for on-line automatic detection of magnetic tiles according to the present invention is provided with a sliding installation hole on the base plate that can slide on the light source installation guide rail.

In the self-adaptive light source device for online automatic detection of magnetic tiles according to the present invention, the hemispherical shell is provided with a notch along the axis so that it can be installed close to the surface of the conveyor belt.

A control method for an adaptive light source device, characterized in that:

a) Under the control of the control system, the camera takes pictures of the samples in the same batch of workpieces on the conveyor belt to obtain the images of the samples;

b) The camera transmits the captured image to the control system, and the control system judges the light intensity of the irregular plane and its chamfered surface of the sample through image processing, and then calculates the correct position of the shading plate;

c) The control system sends a control signal to the stepper motor according to the signal of the correct position of the shading plate, and adjusts the position of the shading plate through the stepping motor, thereby controlling the intensity of incident light on the irregular plane and its chamfered surface of the sample , so that the light intensity reflected into the camera lens by the irregular plane and its chamfered surface of the sample is basically the same;

d) Fine-tune the photo of another sample to obtain the exact position of the shading plate, and save this position in the database of the control system for direct calling in the future.

In the control method of the adaptive light source device according to the present invention, in the step b), the control system can also analyze and calculate the brightness of the end surface area of the magnetic tile of the sample image, and control the driving current of the light source according to the calculation result to change the light source Brightness, self-adaptive to meet the occasions of different illumination requirements.

In the control method of the self-adaptive light source device according to the present invention, in the step b), the control system can control the on-off of the electronic switch of the corresponding LED light source, so as to control the on-off of each LED light source.

The invention has self-adaptive function, and can obtain a clear and stable image by one imaging by automatically controlling the illuminance of the chamfered surface of the end face of the magnetic tile and the arc-shaped plane. Variety of shape and size of magnetic tile end face. In this way, the difficulty of image processing is greatly reduced, the real-time online processing speed is improved, and the automation degree of the detection equipment is improved, which is suitable for the occasion of multi-batch mass production.

Description of drawings

Fig. 1 is a schematic structural diagram of Embodiment 1 of the present invention.

Fig. 2 is a working diagram of Embodiment 1 of the present invention.

Fig. 3 is a schematic structural diagram of Embodiment 2 of the present invention.

Marks in the figure: 1 is the guide sleeve, 2 is the stepper motor, 3 is the mounting plate, 4 is the screw rod, 5 is the nut, 6 is the shading plate, 7 is the hemispherical shell, 8 is the shading ring, 9 is the LED light source, 10 is a base plate, 11 is a gap, 12 is a magnetic tile, and 13 is a transmission belt. the

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in detail.

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Embodiment 1: As shown in Figures 1 and 2, an adaptive light source device is characterized in that: it includes a hemispherical shell 7 with a hole on the top, a bottom plate 10 connected to the bottom of the hemispherical shell 7, and a base plate 10 1. The arc light source group distributed on the inner side of the bottom of the hemispherical shell 7, the camera takes pictures of the magnetic tile 12 on the transmission belt 13 through the hole at the top of the hemispherical shell; the hemispherical shell 7 cuts off a part along the axis to form a gap 11, so The above-mentioned notch can make it close to the surface of the transmission belt and ensure that the magnetic tile is within the field of view of the camera. A sliding installation hole that can slide on the light source installation guide rail is provided on the bottom plate 10. The entire light source device can be mounted on the light source installation guide rail. Slip up, so that the end face of the light source is always close to the end face of the magnetic tile, avoiding the light decay caused by the different distances between the end face of the magnetic tile and the light source of different sizes, and avoiding the problem of insufficient brightness of the end face of the magnetic tile far away from the light source.

The inner surface of the hemispherical shell 7 is evenly sprayed with high reflectivity diffuse reflection light-emitting material, and the light emitted from the arc light source group at the bottom of the inner surface of the hemispherical shell is evenly reflected to form a circular arc with uniform illumination. Illumination area, which can overcome the problem of local reflection caused by the large arc and size of the magnetic tile due to the different distance from the plane light source or ring light source, making the image quality insensitive to changes in the position of the object.

Wherein the arc-shaped light source group is composed of a number of LED light sources 9 that are independent of each other and evenly distributed on the inside of the bottom of the hemispherical shell 7. On the bottom plate 10, the inside of the arc-shaped light source group is provided with a device for preventing the light emitted by the light source from directly Entering the shading ring 8 of the lens, the output end of the power supply is connected with the LED light source, and the brightness of the LED light source can be controlled by controlling the output current of the power supply to obtain an image with appropriate brightness. The LED light source can also be connected to the control system separately, The control system controls the on-off of the corresponding electronic switch to control the on-off of each LED light source to meet different lighting needs.

The radian and size of the arc-shaped light source group are adapted to the casing. The arc-shaped light source adopts LED lights, and LED lights with the same package but different colors can be selected according to needs; the circuit board is an aluminum substrate. According to the needs of parts inspection, the LED light can be controlled individually or as a whole; since the magnetic tile is black-gray and has strong light absorption, in order to avoid motion blur, a certain margin is considered for light attenuation , It is necessary to choose high-brightness LED lights reasonably. In the present invention, the maximum exposure time of the camera is calculated according to the real-time online detection situation, and the brightness and power of the required LED lamp are calculated in combination with the camera sensitivity and other conditions; LED lamps cannot withstand excessively high temperatures, and heat dissipation must be fully considered. Due to the high power of the light source, it is difficult to dissipate heat. Therefore, materials and heat treatment processes that are conducive to heat dissipation are used, and strobe lighting is used to reliably solve the heat dissipation problem and prolong the life of the light source.

A guide sleeve 1 is provided at the opening at the top of the hemispherical housing 7, and a light shield 6 that can move up and down relative to the guide sleeve 1 is provided on the guide sleeve 1 and in the hemispherical housing 7, and a stepping motor 2 The mounting plate 3 is arranged above the hemispherical shell 7, the power output end of the stepping motor 2 is connected with a screw mandrel 4, and the screw mandrel 4 passes through the hemispherical shell 7 and is threadedly connected with the nut 5 provided on the light shielding plate 6, The control part of the stepper motor 2 is electrically connected with the control system. After the stepper motor receives the control signal, it can rotate forward and reverse to adjust the axial position of the shading plate. From the principle of reflection, it can be seen that the light from the upper part of the inner surface of the light source shell irradiating the plane of the magnetic tile has more light entering the lens after reflection, and the light from the lower part of the inner surface of the light source shell irradiating the chamfered surface of the magnetic tile has relatively less light after reflection. into the shot. The shading plate can block and absorb the light irradiating the end surface of the magnetic tile from the upper part of the inner surface of the light source housing to reduce the illuminance irradiating the end surface of the magnetic tile from the upper part, and the shading plate does not control the reflected light below the shading plate. In this way, by reducing the light intensity on the surface of the end face of the magnetic tile, the ratio of the incident light intensity between the chamfered surface and the plane of the end face of the magnetic tile is controlled, so that the intensity of light reflected from different surfaces of the magnetic tile into the lens is basically uniform, and the chamfering of the magnetic tile Facets and planes form a uniform and consistent image. According to the needs of the application occasion, by adjusting the position of the baffle and changing the type of the shading plate, the lighting mode of the light source can be switched between the bright field illumination mode and the dark field illumination mode to meet different application occasions.

A control method for an adaptive light source device, characterized in that:

a) Under the control of the control system, the camera takes pictures of the samples in the same batch of workpieces on the conveyor belt to obtain the images of the samples;

b) The camera transmits the captured image to the control system, and the control system judges the light intensity of the irregular plane and its chamfered surface of the sample through image processing, and then calculates the correct position of the shading plate; the control system can also control the sample Analyze and calculate the brightness of the end surface area of the magnetic tile of the image, and control the driving current of the light source according to the calculation result to change the brightness of the light source, and adapt to meet different illumination requirements; the control system can control the electronic switch of the corresponding LED light source. The control of each LED light source on and off;

c) The control system sends a control signal to the stepper motor according to the signal of the correct position of the shading plate, and adjusts the position of the shading plate through the stepping motor, thereby controlling the intensity of incident light on the irregular plane and its chamfered surface of the sample , so that the light intensity reflected into the camera lens by the irregular plane and its chamfered surface of the sample is basically the same;

d) Fine-tune the photo of another sample to obtain the exact position of the shading plate, and save this position in the database of the control system for direct calling in the future.

Embodiment 2: As shown in Figure 3, compared with Embodiment 1, only a part of the hemispherical shell is not cut off, so that the light source illuminates a circular area. This situation is suitable for the situation where the light source can approach the illuminated object without hindrance.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range. the

Claims (8)

1. An on-line automatic detection adaptive light source device for magnetic tiles, characterized in that it includes a hemispherical casing (7) with holes on the top, a bottom plate (10) connected to the bottom of the hemispherical casing (7) and a set On the bottom plate (10), the arc-shaped light source group is distributed inside the bottom of the hemispherical shell (7), and a guide sleeve (1) is provided at the hole opened on the top of the hemispherical shell (7). On the sleeve (1) and inside the hemispherical shell (7) there is a shading plate (6) that can move up and down relative to the guide sleeve (1), and the shading plate (6) is connected to the power output end of the stepping motor (2) , the inner surface of the hemispherical shell (7) is evenly sprayed with a high reflectance diffuse reflective radiant material, and the control part of the stepping motor (2) is electrically connected to the control system; The arc-shaped light source group is composed of a number of LED light sources (9) that are independent of each other and evenly distributed on the inner side of the bottom of the hemispherical shell (7). The LED light sources (9) are connected to the output end of the power supply, and the power supply and the control system connected, and the electronic switches of the LED light sources (9) are respectively electrically connected to the control system. 2. The online automatic detection adaptive light source device for magnetic tiles according to claim 1, characterized in that: the stepper motor (2) is arranged above the hemispherical shell (7) through the mounting plate (3), The power output end of the stepping motor (2) is connected with a screw rod (4), and the screw rod (4) passes through the hemispherical casing (7) and is threadedly connected with the nut (5) provided on the light shielding plate (6). 3. The online automatic detection adaptive light source device for magnetic tiles according to claim 1, characterized in that: on the bottom plate (10) and inside the arc-shaped light source group, there is a device for preventing the light emitted by the light source from directly entering Shading ring (8) for the lens. 4. The online automatic detection adaptive light source device for magnetic tiles according to claim 1, 2 or 3, characterized in that: on the bottom plate (10) there is a slide that can slide on the light source installation guide rail Mounting holes and locking mechanism. 5. The on-line automatic detection adaptive light source device for magnetic tiles according to claim 1, 2 or 3, characterized in that: the hemispherical shell (7) is provided with a shaft along the axis so that it can be installed close to the surface of the conveyor belt notch (11). 6. A control method for an adaptive light source device as claimed in claim 1, characterized in that: a) Under the control of the control system, the camera takes pictures of the samples in the same batch of workpieces on the conveyor belt to obtain the images of the samples; b) The camera transmits the captured image to the control system, and the control system judges the light intensity of the irregular plane and its chamfered surface of the sample through image processing, and then calculates the correct position of the shading plate; c) The control system sends a control signal to the stepper motor according to the signal of the correct position of the shading plate, and adjusts the position of the shading plate through the stepping motor, thereby controlling the intensity of incident light on the irregular plane and its chamfered surface of the sample , so that the light intensity reflected into the camera lens by the irregular plane and its chamfered surface of the sample is basically the same; d) Fine-tune the photo of another sample to obtain the exact position of the shading plate, and save this position in the database of the control system for direct calling in the future. 7. The control method of the adaptive light source device according to claim 6, characterized in that: in the step b), the control system can also analyze and calculate the brightness of the end surface area of the magnetic tile of the sample image, and control according to the calculation result The driving current of the light source is used to change the brightness of the light source, and it is adaptive to meet the occasions of different illumination requirements. 8. The control method of the adaptive light source device according to claim 6 or 7, characterized in that: in the step b), the control system can control the on-off of the electronic switch of the corresponding LED light source, so as to realize the control of each Control of LED light source on and off.

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