Variable light source illumination system

Abstract

A variable light source illumination system, comprising a light source module, which is composed of at least one LED area light source; a stage, which is horizontally arranged above the light source module; a variable structure, which is located between the light source module and the stage, the variable structure is composed of at least five variable diaphragms arranged longitudinally at equal intervals, and each variable diaphragm is horizontally arranged; a control module, which is located on one side of the variable structure; an imaging lens, which is located above the stage; an imaging module, which is arranged above the imaging lens; and a structure support. The application adjusts the field of view, the exit light aperture angle, the light source illumination and other parameters of the light source module and the variable structure through the control module, so as to obtain a variable light source, which can give more accurate size measurement results when measuring parts of different thicknesses. The application has the advantages of simple structure, strong universality, small occupied space, easy processing and adjustment, low requirement for light source, etc.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of machine vision detection, and particularly relates to a variable light source illumination system. BACKGROUND

[0002] Optical image detection is a technology for detecting precision mechanical parts by using image recognition technology. An optical image detector is used as a representative, which collects the image of an object to be detected through a camera acquisition device, and inputs the image features into an internal processor. The processor detects the profile, size, angle and position of the precision parts by calculation and processing, and is widely used in the detection process of precision parts.

[0003] The existing telecentric light source structure in machine vision detection is complex and occupies a large space. When measuring the size of parts with different thicknesses, the error is large, and often a ring light source needs to be added for supplementary measurement. How to project appropriate light onto the measured object, highlight the measured features, and use appropriate light sources to produce maximum contrast, sufficient brightness, and be insensitive to changes in the position of the parts, so as to obtain ideal measurement results, is a technical difficulty that needs to be solved in the current industry. SUMMARY

[0004] The present application provides a variable light source illumination system to solve the problems in the prior art. The specific technical solutions are as follows:

[0005] A variable light source illumination system, which comprises:

[0006] A light source module composed of at least one LED area light source;

[0007] A stage horizontally arranged above the light source module, a glass window for placing a sample to be measured is embedded in the middle of the stage;

[0008] A variable structure located between the light source module and the stage, the variable structure is composed of at least five variable diaphragms arranged longitudinally at equal intervals, and each variable diaphragm is horizontally arranged and perpendicular to the optical axis of the light source module;

[0009] A control module located on one side of the variable structure, the control module is used to adjust and change the aperture size of the variable diaphragm;

[0010] An imaging lens located above the stage, the imaging lens is used to receive the illumination of the light source module through the sample to be measured;

[0011] An imaging module is arranged above the imaging lens, the imaging module cooperates with the imaging lens to process the image of the illumination through the sample to be measured;

[0012] A structural support for supporting a whole lighting system structure.

[0013] Further, the light-emitting angle of the LED surface light source in the light source module is 60-110°.

[0014] Further, the imaging lens is a double-telecentric lens, and the imaging module is a CCD camera.

[0015] Further, the surface of each variable diaphragm is coated with light-absorbing paint with an absorption rate greater than 98%.

[0016] Further, the distance between adjacent variable diaphragms is 40 mm, and the maximum light transmission aperture of the variable diaphragm is 120 mm.

[0017] Further, the control module comprises a driving motor, the driving motor is vertically arranged, and the power end is axially connected with a driving gear, the driving gear is connected with a first transmission gear set arranged vertically in a meshing manner, the first transmission gear set is connected with a second transmission gear set arranged vertically in a meshing manner, the second transmission gear set and the first transmission gear set are respectively arranged on corresponding gear shafts in an axial direction, and the gear shafts are parallel to the optical axis of the light source module; the second transmission gear set is connected with a diaphragm driving gear set in a meshing manner; each variable diaphragm is axially connected to the gear top surface of the corresponding diaphragm driving gear set through a diaphragm fixing seat matched therewith.

[0018] Further, the number of gears of the first transmission gear set, the second transmission gear set and the diaphragm driving gear set is the same, and they are connected in a meshing manner; the driving gear is connected with the bottom gear of the first transmission gear set in a meshing manner.

[0019] Further, the size of the gears of the diaphragm driving gear set from bottom to top is 210 mm, 190 mm, 175 mm, 165 mm and 150 mm in sequence.

[0020] Further, according to the transmission ratio 5:4:3:2:1, the size of the gears of the second transmission gear set from top to bottom is 70 mm, 51 mm, 35 mm, 22 mm and 10 mm in sequence; and the size of the gears of the first transmission gear set from top to bottom is 10 mm, 29.5 mm, 45 mm, 56.5 mm and 70 mm in sequence.

[0021] The beneficial effects of the present application are:

[0022] The application adjusts the field of view, the exit light aperture angle, the light source illumination and other parameters of the light source module and the variable structure by the control module, so that a variable light source is obtained, which can give more accurate size measurement results when measuring parts with different thicknesses; the application has the advantages of simple structure, strong universality, small occupied space, easy processing and adjustment, low requirement for light source, etc. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The structural schematic diagram of the application is shown;

[0024] Figure 2 The three-dimensional structural schematic diagram of the assembly of the variable structure and the control module in the application is shown;

[0025] Figure 3 The structural sectional view of the assembly of the variable structure and the control module in the application is shown;

[0026] Figure 4 The partial structural schematic diagram of the application in the first working state is shown;

[0027] Figure 5 The partial structural schematic diagram of the application in the second working state is shown;

[0028] Figure 6 The partial structural schematic diagram of the application in the third working state is shown.

[0029] As shown in the figure: 1, light source module; 2, variable structure; 21, variable diaphragm; 22, diaphragm fixing seat; 3, control module; 31, driving motor; 311, driving gear; 32, first transmission gear set; 33, second transmission gear set; 34, gear shaft; 35, diaphragm driving gear set; 4, object table; 5, structural support; 6, imaging lens; 7, imaging module; 8, sample to be measured. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the application more clear and explicit, the application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0031] As shown in the figure, a variable light source illumination system, the system comprises: Figure 1

[0032] The light source module 1 is composed of at least one LED area light source;

[0033] The object table 4 is horizontally arranged above the light source module 1, and a glass window for placing the sample to be measured 8 is embedded in the middle of the object table 4; ​

[0034] a variable structure 2 between the light source module 1 and the object table 4, the variable structure 2 is composed of at least five or more variable diaphragms 21 arranged longitudinally at equal intervals, and each variable diaphragm 21 is arranged horizontally and perpendicular to the optical axis of the light source module 1;

[0035] a control module 3 on one side of the variable structure 2, the control module 3 is used to adjust the size of the variable diaphragm 21;

[0036] an imaging lens 6 above the object table 4, the imaging lens 6 is used to receive the light illumination through the sample 8 to be measured;

[0037] an imaging module 7 arranged above the imaging lens 6, the imaging module 7 cooperates with the imaging lens 6 to image the light illumination through the sample 8 to be measured;

[0038] a structure support 5 for supporting and fixing the entire illumination system structure.

[0039] By adopting the above technical scheme, the system adjusts and changes the field of view, exit pupil aperture angle, light source illumination and other parameters of the light source module 1 and the variable structure 2 through the control module 3, so as to obtain a variable light source, which can give more accurate size measurement results when measuring parts of different thicknesses; the system has the advantages of simple structure, strong universality, small occupied space, easy processing and adjustment, and low requirement on light source.

[0040] The variable light source of the system compared with the telecentric light source in machine vision detection, the design has great reduction in cost, from the space volume, the design only has an LED area light source light-emitting plate, the space size can be adjusted according to the lens depth of field of machine vision detection.

[0041] The size of the light transmission aperture of each variable diaphragm 21 in the variable structure 2 can be consistent or different according to the detection target requirements; each variable diaphragm 21 is placed horizontally and perpendicular to the optical axis, and the uppermost variable diaphragm 21 determines the field of view size of the detection plane. The variable structure 2 changes the size of the LED area light source, changes the illumination area of the object table 4, and changes the aperture angle of the edge profile of the sample 8 to be measured on the object table 4.

[0042] The control module 3 outputs a signal to control the change of the variable structure 2 by computer. The structure support 5 is used to support and fix the light source module 1, the variable structure 2, the control module 3, the object table 4, and the imaging lens 6 and the imaging module 7.

[0043] Preferably, the light-emitting angle of the LED surface light source in the light source module 1 is 60°-110°.

[0044] Preferably, the imaging lens 6 is a double-telecentric lens; and the imaging module 7 is a CCD camera.

[0045] Preferably, the surface of each variable diaphragm 21 is coated with light-absorbing paint with an absorption rate greater than 98%.

[0046] By using the above technical solution, the light-absorbing paint can absorb stray light outside the field of view.

[0047] Preferably, the distance between adjacent variable diaphragms 21 is 40 mm, and the maximum light aperture of the variable diaphragm 21 is 120 mm.

[0048] As shown in Figure 2 and 3 The control module 3 includes a driving motor 31, which is vertically arranged, and has a driving gear 311 axially connected to the power end, a first transmission gear set 32 vertically arranged and meshingly connected to the driving gear 311, a second transmission gear set 33 vertically arranged and meshingly connected to the first transmission gear set 32, the second transmission gear set 33 and the first transmission gear set 32 being respectively axially arranged on corresponding gear shafts 34, and the gear shafts 34 being parallel to the optical axis of the light source module 1; the second transmission gear set 33 is meshingly connected to a diaphragm driving gear set 35; each variable diaphragm 21 is axially connected to the gear top surface of the corresponding diaphragm driving gear set 35 through a diaphragm fixing seat 22 adapted thereto.

[0049] By using the above technical solution, the control module 3 is designed according to the on-off state and the on-off size of each layer of variable diaphragms 21; the driving motor 31 drives the driving gear 311 to rotate forward, and the first transmission gear set 32 and the second transmission gear set 33 control the diaphragm driving gear set 35 to rotate from top to bottom according to the designed ratio, so as to adjust and change the light aperture size of the variable diaphragm 21.

[0050] As shown in Figure 2 and 3 The number of gears of the first transmission gear set 32, the second transmission gear set 33, and the diaphragm driving gear set 35 is the same, and they are meshingly connected to each other; the driving gear 311 is meshingly connected to the bottom gear of the first transmission gear set 32.

[0051] By using the above technical solution, the first transmission gear set 32 and the second transmission gear set 33 are respectively axially arranged on corresponding gear shafts 34, and the gears from top to bottom are respectively radially meshingly connected, and the diaphragm driving gear set 35 and the second transmission gear set 33 are respectively radially meshingly connected from top to bottom.

[0052] As shown in Figure 2 and 3 , the gear sizes of the diaphragm driving gear set 35 from bottom to top are 210mm, 190mm, 175mm, 165mm, 150mm in turn.

[0053] As shown in Figure 2 and 3 , according to the transmission ratio 5:4:3:2:1, the gear sizes of the second transmission gear set 33 from top to bottom are 70mm, 51mm, 35mm, 22mm, 10mm in turn; the gear sizes of the first transmission gear set 32 from top to bottom are 10mm, 29.5mm, 45mm, 56.5mm, 70mm in turn.

[0054] By adopting the above technical scheme, the size of the illumination area can be controlled, and the illumination aperture angle irradiated to the edge of the sample to be measured 8 can be controlled.

[0055] As shown in Figures 4-6 , in the implementation of the present application, there can be three different working states:

[0056] The first working state: the light transmission apertures of all the variable diaphragms 21 in the variable structure 2 are consistent, and are relatively large, so that the field of view is large, and the exit light aperture angle is large, which is suitable for the case that the sample to be measured 8 is relatively thin;

[0057] The second working state: the light transmission apertures of all the variable diaphragms 21 in the variable structure 2 are consistent, and are relatively small, so that the field of view is small, and the exit light aperture angle is small, which is suitable for the case that the sample to be measured 8 is relatively thick;

[0058] The third working state: the light transmission apertures of all the variable diaphragms 21 in the variable structure 2 can be adjusted and changed according to the designed ratio by the control module 3, so that the size of the field of view can be controlled, and the exit light aperture angle can be controlled, which is suitable for the case that the sample to be measured 8 has different specific sizes.

[0059] The following is a comparison experiment between the prior art telecentric light source and the variable light source of the present application made by using lighttools simulation software:

[0060] Prior art simulation experiment one: the telecentric light source with a 1.32° aperture angle, the distance between the light source and the measured object is 100mm, the measured object parameters are a radius of 12mm and a thickness of 10mm, each surface is set to be reflective, the distance between the measured object and the lens is 200mm, the lens is a double-telecentric lens with a magnification of 1 / 6. The theoretical size of the measured object on the image plane is a circle with a radius of 2mm. The coordinate region brightness value data is shown in Table One as follows:

[0061] Table One:

[0062]

[0063]

[0064] The second simulation experiment of the present application: the LED area light source with the light source parameter 100° aperture angle, the variable structure size inner circle radius 14mm, outer circle radius 30mm, the distance between the variable diaphragm 10mm, the distance between the light source and the measured object 100mm, the measured object parameter radius 12mm, thickness 10mm, each surface is set to reflect, the distance between the measured object and the lens 200mm, the lens is a double telecentric lens with magnification 1 / 6). The following Table 2 shows the coordinate area brightness value data:

[0065] Table 2:

[0066]

[0067]

[0068] Simulation experiment result: according to Table 1 and Table 2, through the comparison of the brightness value, in the simulation experiment 1, the measured physical size is 2mm, and there is no obvious brightness gradient change in the transition boundary position, and the optical system imaging and image processing algorithm cannot effectively extract the boundary information; however, in the simulation experiment 2, the measured physical size is 2mm, and there is a clear brightness gradient change in the transition area of-2.02857~ -1.97143, and the optical system imaging and image processing algorithm can better extract the true value of the measured object with a certain thickness.

[0069] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A variable light source illumination system, characterized in that, The system comprises: a light source module (1) composed of at least one LED surface light source; a stage (4) horizontally arranged above the light source module (1), with a glass window in the middle for placing a sample (8) to be tested; a variable structure (2) between the light source module (1) and the stage (4), composed of at least five variable diaphragms (21) arranged longitudinally at equal intervals, each variable diaphragm (21) being horizontally arranged and perpendicular to the optical axis of the light source module (1); a control module (3) on one side of the variable structure (2), used to adjust the aperture size of the variable diaphragm (21); an imaging lens (6) above the stage (4), used to receive the light passing through the sample (8) to be tested; an imaging module (7) arranged above the imaging lens (6), cooperating with the imaging lens (6) to image the light passing through the sample (8) to be tested; a structure support (5) for supporting and fixing the entire illumination system structure; the distance between adjacent variable diaphragms (21) is 40 mm, and the maximum aperture of the variable diaphragm (21) is 120 mm; the control module (3) comprises a drive motor (31) vertically arranged, with a driving gear (311) axially connected to the power end, a first transmission gear set (32) vertically connected to the driving gear (311), a second transmission gear set (33) vertically connected to the first transmission gear set (32), the second transmission gear set (33) and the first transmission gear set (32) being respectively axially arranged on corresponding gear shafts (34), and the gear shafts (34) being parallel to the optical axis of the light source module (1); the second transmission gear set (33) is engaged with a diaphragm drive gear set (35); each variable diaphragm (21) is axially connected to the gear top surface of the corresponding diaphragm drive gear set (35) through a diaphragm fixing seat (22) adapted thereto; the number of gears of the first transmission gear set (32), the second transmission gear set (33) and the diaphragm drive gear set (35) is the same, and they are engaged with each other; the driving gear (311) is engaged with the bottom gear of the first transmission gear set (32); the gear sizes of the diaphragm drive gear set (35) from bottom to top are 210 mm, 190 mm, 175 mm, 165 mm and 150 mm; according to the transmission ratio 5:4:3:2:1, the gear sizes of the second transmission gear set (33) from top to bottom are 70 mm, 51 mm, 35 mm, 22 mm and 10 mm; the gear sizes of the first transmission gear set (32) from top to bottom are 10 mm, 29.5 mm, 45 mm, 56.5 mm and 70 mm.

2. A variable light source illumination system according to claim 1, characterized in that: The light-emitting angle of the LED surface light source in the light source module (1) is 60-110 degrees.

3. A variable light source illumination system according to claim 1, characterized in that: The imaging lens (6) is a double-telecentric lens; and the imaging module (7) is a CCD camera.

4. A variable light source illumination system according to claim 1, characterized in that: The surface of each variable diaphragm (21) is coated with a light-absorbing paint with an absorption rate greater than 98%.

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