CN110426183B - System and method for testing field angle of lens - Google Patents
System and method for testing field angle of lens Download PDFInfo
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- CN110426183B CN110426183B CN201910662020.8A CN201910662020A CN110426183B CN 110426183 B CN110426183 B CN 110426183B CN 201910662020 A CN201910662020 A CN 201910662020A CN 110426183 B CN110426183 B CN 110426183B
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
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Abstract
The invention discloses a system for testing the field angle of a lens, wherein a first point mark is arranged right in front of the lens to be tested and is positioned in the center of an image obtained on an imaging module; when the lens moves to the first point mark direction on the linear moving module to the end point position where the second point mark and the third point mark just move to the left edge and the right edge in imaging, according to the distance between the end point position and the connecting line of the second point mark and the third point mark and the length of the connecting line of the second point mark and the third point mark, the included angle between the end point position and the connecting line of the second point mark and the third point mark is determined, and the field angle of the lens is obtained. The invention can effectively improve the testing precision and save the testing time. The invention also discloses a method for testing the field angle of the lens.
Description
Technical Field
The invention relates to the technical field of optical systems, in particular to a system and a method for testing the field angle of a lens.
Background
In testing the field angle of the optical lens, a ruler, a graphometer, and other tools are generally used. However, this only enables rough measurement of relevant data, and the measurement accuracy is low. Especially for a wide-angle lens (the angle of view is greater than 180 degrees), splicing measurement is needed, and thus the measurement accuracy is more limited.
Disclosure of Invention
The present invention is directed to overcome the above-mentioned drawbacks of the prior art, and provides a system and a method for testing the field angle of a lens.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a system for testing the field angle of a lens, comprising:
the linear moving module is used for driving a lens to be tested loaded by the linear moving module to move horizontally, and the lens is arranged right opposite to the moving direction;
the imaging module is used for obtaining imaging for observation through the lens;
the identification module comprises a first point identification to a third point identification, the first point identification is arranged right in front of the lens and is positioned in the center of the obtained image, the second point identification and the third point identification are arranged on two sides right in front of the lens in equal height symmetry, and a connecting line of the second point identification and the third point identification is positioned at the front side position of the first point identification relative to the moving direction of the lens;
when the lens moves to the first point mark direction and changes to the end point positions of the second point mark and the third point mark which are just at the left edge and the right edge in the imaging process, determining included angles between the end point positions and the connecting line of the second point mark and the third point mark respectively according to the distance between the end point positions and the connecting line of the second point mark and the third point mark and the length of the connecting line of the second point mark and the third point mark, and obtaining the field angle of the lens.
Further, the linear moving module is an electric cylinder, the electric cylinder is provided with a guide rail and a sliding block which are matched, and the lens is arranged on the sliding block.
Further, the lens is loaded on the sliding block through a height-adjustable clamp.
Furthermore, a scale is arranged on the guide rail along the moving direction.
Further, the imaging module is a camera including the lens.
Further, the distance between the second point identifier and the third point identifier is fixed.
Further, the identification module further comprises a first vertical ruler to a third vertical ruler, and the first point identification to the third point identification are respectively arranged on the first vertical ruler to the third vertical ruler.
Furthermore, the identification module further comprises two flat plates which are intersected to form a certain included angle, the second point identification and the third point identification are respectively arranged on the outer side positions of the two flat plates, and the first point identification is arranged on the vertical intersection line position of the two flat plates.
The method for testing the field angle of the lens comprises the following steps:
setting the length of a connecting line of the second point mark and the third point mark and the distance between the connecting line and the lens to be tested in a static state;
acquiring images of the first point identifier to the third point identifier through the lens;
adjusting the first point marker to be in a central position in the imaging so as to correct the lens center;
horizontally moving the lens towards a first point mark direction until the second point mark and the third point mark change to moving end positions which are just positioned at the left edge and the right edge in the imaging process, and recording the distance between the end positions and the connecting line;
and calculating included angles between the end point position and a connecting line of the second point identifier and the third point identifier respectively according to the thigh hooking law to obtain the field angle of the lens.
Further, distortion correction is performed on the acquired image before correcting the lens center.
The invention can effectively improve the testing precision and save the testing time.
Drawings
Fig. 1 is a schematic structural diagram of a system for testing an angle of view of a lens according to a preferred embodiment of the invention.
Fig. 2 is a schematic diagram illustrating a method for testing an angle of view of a lens according to a preferred embodiment of the invention.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
In the following detailed description of the embodiments of the present invention, in order to clearly illustrate the structure of the present invention and to facilitate explanation, the structure shown in the drawings is not drawn to a general scale and is partially enlarged, deformed and simplified, so that the present invention should not be construed as limited thereto.
In the following detailed description of the present invention, please refer to fig. 1 and 2, in which fig. 1 is a schematic structural diagram of a system for testing a lens field angle according to a preferred embodiment of the present invention, and fig. 2 is a schematic diagram of a method for testing a lens field angle according to a preferred embodiment of the present invention. As shown in fig. 1, a system for testing a field angle of a lens according to the present invention may include: the system comprises a linear moving module, an imaging module, an identification module (comprising a first point identification a, a second point identification e 'and a third point identification f'), and the like.
Please refer to fig. 1. The linear moving module is used for driving a lens (not shown) loaded on the linear moving module and used for testing the field angle to be tested to move horizontally. As an alternative embodiment, the linear movement module may be an electric cylinder. The present invention is not limited thereto.
Taking an electric cylinder as an example, the electric cylinder is provided with a linear guide rail 10 and a slider (not shown) which forms a sliding fit with the guide rail 10. The lens is arranged on the sliding block.
As a preferred embodiment, the lens may be loaded on the slider by a height adjustable jig 11 so that the height of the lens may be conveniently adjusted to be compatible with the height of the first point mark a.
The lens can be fixedly arranged on the sliding block, and the height of the first point mark a can be adjusted to adapt to the height of the lens.
In order to measure the vertical distance between the lens and the line e 'f' (line e 'f' is shown) connecting the second point mark e 'and the third point mark f', a scale 101 with a certain accuracy may be provided on the guide rail 10 in the moving direction (the scale 101 is shown in the lower part of the figure in a virtual manner, and may be accurate to a millimeter, for example). Meanwhile, at the projection position of a certain height right below the second dot mark e 'and the third dot mark f', another scale (for example, a horizontal scale in meters, which may be accurate to millimeters, as shown in fig. 2) may be disposed between the two projection points e and f of the second dot mark e 'and the third dot mark f', and the two scales may be kept orthogonal. Therefore, the vertical distance between the lens and the line e 'f' connecting the second point mark e 'and the third point mark f' and the length of the line e 'f' connecting the second point mark e 'and the third point mark f' (the distance between the second point mark e 'and the third point mark f') can be intuitively understood. The distance between the second point mark e ' and the third point mark f ' can be preset according to the distance between the second point mark e ' and the initial position of the lens, that is, the distance between the second point mark e ' and the third point mark f ' is fixed and known.
The lens is arranged on the guide rail 10 against the direction of its movement, i.e. the lens is arranged facing the first point indication a.
The imaging module is used for obtaining observation imaging from the first point mark to the third point mark a, e 'and f' through the lens. As an optional implementation manner, the imaging module may be a camera including a lens, and images of the first to third point markers a, e ', and f' may be obtained on the camera by imaging the first to third point markers a, e ', and f'. Thus, the system of the present invention can be used to test the field angle of lenses configured on various types of cameras.
The image (image) obtained on the camera for the first point marker third point markers a, e ', f' is dynamically changed when the lens is moved in the direction of the first point marker a. Because the second point mark e 'and the third point mark f' will change their positions in the image, specifically from the middle of the image to the edge positions on both sides.
Please refer to fig. 1 in combination with fig. 2. The identification module comprises a first point identification a, a second point identification e 'and a third point identification f', etc. The first point mark a is arranged right in front of the lens and is positioned in the center of the obtained image, namely the first point mark a is arranged at a position relative to the center of the lens. In other words, the center of the lens is corrected by the first point mark a.
The second point mark e 'and the third point mark f' are equal to the first point mark a in height, and the second point mark e 'and the third point mark f' are symmetrically positioned on the front side of the first point mark a. That is, the first point index a is located at a rear side position of the second point index e 'and the third point index f' with reference to the lens moving direction.
After the distance (the line segment e ' f ') between the second point mark e ' and the third point mark f ' is determined, the distance between the first point mark a and the line e ' between the second point mark e ' and the third point mark f ' is far or near (or the size of the included angle γ between the line ae ' between the first point mark a and the second point mark e ' and the line af ' between the first point mark a and the third point mark f ') is shown), that is, the size of the field angle ω that can support the lens is determined. The farther the distance between the first point identifier a and the connecting line e 'f' between the second point identifier e 'and the third point identifier f' (or the smaller the included angle γ between the connecting line ae 'between the first point identifier a and the second point identifier e' and the connecting line af 'between the first point identifier a and the third point identifier f'), the larger the field angle ω of the lens that the system can support the test.
When the lens mounted on the driving rail 10 moves toward the first point mark a, the second point mark e 'and the third point mark f' will change their positions in the image, and gradually move toward the edge positions at both sides from the middle of the image.
When the second point mark e 'and the third point mark f' move to the end positions right at the left and right edges in the imaging process, an included angle ω (θ) between the connecting line b 'e' of the end position b 'and the second point mark e' and the connecting line b 'f' of the end position b 'and the third point mark f' and the connecting line b 'f' of the third point mark f 'can be determined according to the distance (i.e., the length of the line segment bc in the figure) between the end position b (b') and the connecting line e 'f' between the second point mark e 'and the third point mark f' and the length of the connecting line e 'f' between the second point mark e 'and the third point mark f', so that the field angle ω of the lens can be obtained. The angle θ is equal to the angle ω, i.e., the angle θ is the perpendicular projection angle of the angle ω.
Please refer to fig. 1. As an alternative embodiment, the second point mark e 'and the third point mark f' may be respectively disposed on the two flat plates 12 and 13; and the two plates 12, 13 are intersected at an angle γ, such that the second point mark e 'and the third point mark f' are respectively located at outer positions of the two intersected plates 12, 13, for example, at outer edges of the two intersected plates 12, 13. Meanwhile, the first point mark a may be located at the intersection of the two panels 12, 13, for example, at the inner seam of the two intersecting panels 12, 13, i.e., the first point mark a is theoretically located at the intersection shared by the two panels 12, 13.
The first to third point markers a, e ', f' and the two intersecting plates 12, 13 together form the main structure of the marker module.
The marks a, e 'and f' from the first point mark to the third point mark can be manufactured on the two flat plates 12 and 13 in an engraving way; alternatively, the first to third point marks a, e ', f' may be formed on the two flat plates 12, 13 by means of adhesion; alternatively, the first to third dot markers a, e ', f' may be irradiated with laser light on the two flat plates 12, 13. And so on. Namely, the first point mark a, the second point mark e ', and the center points of the third point mark f' are the points a, e ', f' shown in the figure, respectively.
The two plates 12, 13 can be of any suitable shape, as long as the relative positions of the first to third point marks a, e ', f' thereon are ensured. The length of the bottom side of the illustrated two rectangular flat plates 12 and 13 may be any length, but when the length is set longer, the accuracy will be higher.
As another alternative embodiment, the first point mark a may be provided on one first vertical bar, the second point mark e 'may be provided on one second vertical bar, and the third point mark f' may be provided on one third vertical bar. The first vertical ruler to the third vertical ruler are vertically arranged facing the lens and are parallel to each other.
The marks a, e 'and f' from the first point mark to the third point mark and the first vertical ruler to the third vertical ruler jointly form the main structure of the mark module.
The following describes a method for measuring a field angle of a lens according to the present invention in detail with reference to the following embodiments and accompanying drawings.
Please refer to fig. 2 in conjunction with fig. 1. The method for testing the field angle of the lens can use the system for testing the field angle of the lens.
As shown in fig. 1, the angle ω is the angle of view of the lens to be solved, and is equal to the angle θ. When the lens is moved, when the lens is moved to a straight line formed by two points ef, the wide-angle lens with the angle of view larger than 180 degrees is described.
As shown in fig. 2, the method may include the steps of:
first, the length of a connecting line e 'f' between the second point mark e 'and the third point mark f' and the distance between the connecting line e 'f' and the lens to be tested in a static state (initial state) are set. A first point mark a for correcting the lens center may be marked on an intersection line of the two intersecting plates 12, 13 as described above, and a second point mark e 'and a third point mark f' for testing the magnitude of the field angle ω may be marked on edge positions of the two intersecting plates 12, 13.
Then, images of the first to third point markers a, e ', f' may be acquired through the lens on the camera.
Then, distortion correction can be performed on the acquired image to ensure the measurement accuracy. The distortion correction may be performed using an algorithm corresponding to those in the art.
Then, the adjustment is made so that the first point mark a is centered in imaging to correct the lens center.
Next, the test can be performed. The lens is slowly moved horizontally in the direction of the first point mark a while observing the image appearing in the camera.
When the second point mark e ' and the third point mark f ' are shifted to be just within the visual field range of the left and right edges in the imaging of the camera, the movement of the lens is stopped, and the position is marked as an end position b (b '). At this time, the vertical distance between the end position b and the connecting line ef (or the vertical distance between the point b ' and the line segment e ' f '), that is, the distance between the point b and the point c, that is, the length represented by the line segment bc in the figure, can be recorded according to the scale on the guide rail 10.
Then, an included angle ω between a line b ' e ' connecting the end point position b ' and the second point mark e ' and a line b ' f connecting the end point position b ' and the third point mark f ' can be calculated according to the collusion thigh law, so as to obtain the field angle ω of the lens.
In the following, the field angle ω is replaced by FOV, and the calculation method is specifically as follows:
(1) when FOV < 180 °, for example, the lens is moved to point b on the side above the line ef in fig. 2, and the field angle is measured using the following formula:
tanα＝ec/bc
FOV＝2α
the measured field angle at this time was about 90 degrees.
(2) When the FOV is 180 °, i.e. when the lens stays at the point c on the straight line of ef, the field angle is 180 °;
(3) when FOV > 180 deg., the lens will move to the other side of the line ef, e.g. at the g point shown, and the field angle is measured using the following equation:
tanβ＝ec/gc
FOV＝360°-2β
the measured lens angle of view at this time was about 213.4 degrees.
The system and the method can effectively improve the precision of testing the field angle of the lens and save the testing time.
The above description is only a preferred embodiment of the present invention, and the embodiments are not intended to limit the scope of the present invention, so that all equivalent structural changes made by using the contents of the specification and the drawings of the present invention should be included in the scope of the present invention.
Claims (10)
1. A system for testing the field angle of a lens, comprising:
the linear moving module is used for driving a lens to be tested loaded by the linear moving module to move horizontally, and the lens is arranged right opposite to the moving direction;
the imaging module is used for obtaining imaging for observation through the lens;
the identification module comprises a first point identification to a third point identification, the first point identification is arranged right in front of the lens and is positioned in the center of the obtained image, the second point identification and the third point identification are arranged at the same height as the first point identification and are symmetrically positioned on the front side of the first point identification, and the distance between the second point identification and the third point identification is fixed;
when the lens moves to the first point mark direction and changes to the end point positions of the second point mark and the third point mark which are just at the left edge and the right edge in the imaging process, determining included angles between the end point positions and the connecting line of the second point mark and the third point mark respectively according to the distance between the end point positions and the connecting line of the second point mark and the third point mark and the length of the connecting line of the second point mark and the third point mark, so as to obtain the field angle of the lens, and when the lens moves to the position which is in the same plane with the second point mark and the third point mark, the field angle is 180 degrees; when the lens is moved to the rear side of the second and third point marks, the angle of view is greater than 180 °.
2. The system for testing the field angle of a lens according to claim 1, wherein the linear moving module is an electric cylinder, the electric cylinder is provided with a guide rail and a slide block which are matched with each other, and the lens is arranged on the slide block.
3. The system for testing the field angle of claim 2, wherein the lens is loaded on the slide by a height adjustable clamp.
4. The system for testing the field angle of a lens according to claim 2, wherein a scale is provided on the guide rail along the moving direction.
5. The system for testing the field angle of a lens according to claim 1, wherein the imaging module is a camera including the lens.
6. The system for testing the field angle of a lens according to claim 1, wherein the distance between the second point marker and the third point marker is fixed.
7. The system for testing the field angle of a lens according to claim 1, wherein the identification module further includes a first vertical ruler to a third vertical ruler, and the first to third point identifications are respectively disposed on the first to third vertical rulers.
8. The system for testing the field angle of a lens according to claim 1, wherein the identification module further includes two flat plates intersecting at an included angle, the second point identifier and the third point identifier are respectively disposed at outer positions of the two flat plates, and the first point identifier is disposed at a vertical intersection position of the two flat plates.
9. A method for testing the field angle of a lens is characterized by comprising the following steps:
setting the length of a connecting line of a second point mark and a third point mark and the distance between the connecting line and a lens to be tested in a static state, wherein the distance between the second point mark and the third point mark is fixed;
acquiring images of the first point identifier to the third point identifier through the lens;
adjusting the first point marker to be in a central position in the imaging so as to correct the lens center;
horizontally moving the lens towards a first point mark direction until the second point mark and the third point mark change to moving end positions which are just positioned at the left edge and the right edge in the imaging process, and recording the distance between the end positions and the connecting line;
calculating included angles between the terminal position and a connecting line of the second point identifier and the third point identifier respectively according to a colluding thigh law to obtain a field angle of the lens, wherein the field angle is 180 degrees when the lens moves to be in the same plane with the second point identifier and the third point identifier; when the lens is moved to the rear side of the second and third point marks, the angle of view is greater than 180 °.
10. The method for testing the field angle of a lens according to claim 9, wherein the distortion correction is performed on the acquired image before the lens center is corrected.
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| CN208297099U (en) * | 2018-06-08 | 2018-12-28 | 中山联合光电科技股份有限公司 | Angle of view measuring device |
| CN109827524A (en) * | 2019-03-22 | 2019-05-31 | 京东方科技集团股份有限公司 | Light angle measuring device and display screen go out the light angle measurement method of light |
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| JP2012058139A (en) * | 2010-09-10 | 2012-03-22 | Fujifilm Corp | Lens inspection apparatus and method |
| US8619248B2 (en) * | 2012-04-05 | 2013-12-31 | Geo Semiconductor Inc. | System and method for calibrating ultra wide-angle lenses |
| CN106441212B (en) * | 2016-09-18 | 2020-07-28 | 京东方科技集团股份有限公司 | Device and method for detecting field angle of optical instrument |
| CN206772557U (en) * | 2017-01-04 | 2017-12-19 | 北京威斯顿亚太光电仪器有限公司 | A kind of detection means for medical rigid pipe endoscope optical parametric |
| CN107702895A (en) * | 2017-09-28 | 2018-02-16 | 信利光电股份有限公司 | A kind of angle of view measuring method |
| CN107749981B (en) * | 2017-11-15 | 2024-01-30 | 歌尔光学科技有限公司 | Camera field angle measurement method and system |
| CN109738157A (en) * | 2018-12-11 | 2019-05-10 | 信利光电股份有限公司 | Field angle detection method, device and the readable storage medium storing program for executing of structured light projection device |
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| CN106370669A (en) * | 2016-08-16 | 2017-02-01 | 凌云光技术集团有限责任公司 | Full-visual-angle detection apparatus and system |
| CN208297099U (en) * | 2018-06-08 | 2018-12-28 | 中山联合光电科技股份有限公司 | Angle of view measuring device |
| CN109827524A (en) * | 2019-03-22 | 2019-05-31 | 京东方科技集团股份有限公司 | Light angle measuring device and display screen go out the light angle measurement method of light |
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