CN115655104A - Method for measuring size of concave object by multi-directional image capture - Google Patents
Method for measuring size of concave object by multi-directional image capture Download PDFInfo
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- CN115655104A CN115655104A CN202211257703.3A CN202211257703A CN115655104A CN 115655104 A CN115655104 A CN 115655104A CN 202211257703 A CN202211257703 A CN 202211257703A CN 115655104 A CN115655104 A CN 115655104A
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- 238000005259 measurement Methods 0.000 abstract description 9
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Abstract
The invention discloses a method for measuring the size of an inward concave object for multi-directional image acquisition, which relates to the field of size measurement and comprises the following steps: placing an object to be measured at an appointed photographing position, and aligning a surface to be measured with a camera at a fixed position; sequentially and independently opening at least two light sources uniformly surrounding the central axis of the surface to be measured and taking a picture, wherein the at least two light sources are obliquely arranged towards the center of the surface to be measured; carrying out pixel comparison on at least two obtained photos, and reserving dark pixel points; recombining and arranging the reserved dark pixels to form a new image; and analyzing the formed new image by using a computer to measure the required size. The invention takes pictures of the measured object for many times through the camera, the lighting angle of each shooting is different, different shadows are formed, and each deeper pixel point is synthesized into a new picture again for the computer to identify, thereby greatly reducing the identification error and saving the cost.
Description
Technical Field
The invention relates to the field of size measurement, in particular to a method for measuring the size of an inward concave object by multi-directional image capture.
Background
The measurement of the size of some concave objects is often needed in the production process and the daily life of people.
In the prior art, the measurement technology mainly includes contact measurement and image capture processing measurement technology of plane plus scanning, if parameters such as inner diameter, outer diameter, length, width and the like of an inward concave object such as a tubular object and a box-shaped object need to be measured. The contact measurement is as the name implies, that is, an object is measured by using a measuring piece which is similar to a vernier caliper and contacts with the object, but the measuring method has low efficiency and poor precision, is easily limited by the environment, and cannot contact the measured object in some occasions. The image-taking processing and measuring technology of plane plus scanning has the disadvantages of long time consumption and high cost; if the photographing recognition technology is directly adopted, the computer is easy to recognize the object outline in the image because of difficulty in recognizing the object outline.
Disclosure of Invention
Aiming at the problem that errors are easily generated when the computer is difficult to identify the outline of a picture image of an object in the prior art so as to measure the sizes of the object, the invention aims to provide a method for measuring the size of the concave object for multi-directional image capture, so as to solve the problem and enable the computer to quickly and accurately identify the contour line of the object, thereby accurately and quickly measuring the geometric size parameters of the object, and the specific technical scheme is as follows:
a method for measuring the size of an inward concave object by multi-directional image capture is characterized in that: the method comprises the following steps:
s1: placing an object to be measured at an appointed photographing position, and aligning a surface to be measured with a camera at a fixed position;
s2, sequentially and independently opening at least two light sources uniformly surrounding the central axis of the surface to be measured and taking a picture, wherein the at least two light sources are obliquely arranged towards the center of the surface to be measured;
s3: performing pixel comparison on at least two photos obtained in the step S2, and reserving dark pixel points;
s4: recombining and arranging the dark pixels reserved in the S3 to form a new image;
s5: the new image formed in S4 is analyzed by a computer to measure the desired size.
Compared with the prior art, the invention has the beneficial effects that:
the invention takes pictures of the measured object through the camera for many times, the lighting angle of each picture is different, the characteristic of the concave object is utilized, the taken pictures can form shadows with different angles, the pixel contrast is utilized to select dark pixel points, and the selected deeper pixel points are recombined into a new picture for the computer to identify.
Preferably: the number of the light sources is 2-4.
It is possible to completely synthesize the shadow having the same shape as the object to be measured by using at least two light sources, and if too many light sources are provided to take a picture many times, it is not only time consuming but also cost is increased, so 2-4 light sources are preferable.
Preferably: the number of the light sources is 4.
When two light sources are arranged, the included angle equivalent to image capture is 180 degrees, however, due to various reasons, the obtained shadow area is difficult to reach 180 degrees, and the included angle formed by the shadow area is generally slightly less than 180 degrees, so that a small part of the synthesized picture is difficult to identify when two light sources are selected;
although the defects of two light sources can be made up by adopting three light sources, the three light sources need to be accurately installed on three vertexes of an equilateral triangle, the accuracy requirement of an installation point is very high, and the production cost is improved to a certain extent, so that 4 light sources are selected as the optimal scheme at present.
Preferably: the included angle between the irradiation direction of the light source and the surface to be measured is 20-60 degrees.
After the position of the light source is fixed, the included angle between the light source irradiation and the surface of the measured object has great influence on the definition of the outline of the measured object. When the light source is less than 20 degrees, the whole picture is dark, the color difference with the surrounding scene is small, the recognition threshold value is low, and the contour misjudgment is easily caused, so that an external point is recognized during measurement, and the measured value is larger than the true value; when the light source is larger than 60 degrees, the whole picture has high brightness, the outline of the measured object surface and the outline of the inner non-measured surface have high brightness value, and the outline point can not be identified by a computer easily, so that the size value can not be measured.
Further: the at least two light sources are located in the same vertical plane.
By ensuring that the light sources are in the same vertical plane, the parameters of the light sources such as the irradiation intensity, the irradiation area and the like of the surface to be measured can be ensured to be relatively consistent, and the consistency of the parameters of the shadow area, the color depth and the like of each photo can be ensured as far as possible.
Further, the method comprises the following steps: the step S2 is completed in a dark environment.
The method is completed in a dark environment, the dark pixel points of the shot photo are more obvious, the probability of misjudgment during pixel comparison is low, and the probability of errors is smaller when a computer identifies the synthesized graph.
Further: further comprising S6: the computer transmits the information on the size measured in S5 to the controller.
The measured size information is transmitted to the controller, so that the further utilization of the size information can be facilitated, and particularly, the next machining process can be carried out in the industry according to the size information of some raw materials or workpieces.
Drawings
Fig. 1 is a schematic front view (with an object omitted) showing a positional relationship between a camera and a light source in embodiment 1;
FIG. 2 is a left side view of the camera and light source positional relationship of FIG. 1;
FIG. 3 is a diagram showing the photographing effect of the upper light source in embodiment 2 when it is turned on;
FIG. 4 is a diagram showing the photographing effect of the embodiment 2 when the lower light source is turned on;
fig. 5 is a graph of the combined effect of fig. 3 and 4.
Fig. 6 is a diagram of the effect of shooting by using light sources with different angles for objects with different inner diameters.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
In the description of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The first embodiment is as follows:
referring to fig. 1 and 2, a camera 1 is installed in a closed box to ensure a dark environment during shooting, and a surface 3 to be measured of an object is placed at a position opposite to the camera 1. Still set up 4 light sources 2 in the box, four light sources 2 evenly encircle in the axis setting of the face 3 that awaits measuring, and all set up towards the center of the face 3 that awaits measuring, because the object that awaits measuring is concave, the picture that every light source 2 was clapped can form about central angle for the shadow of 180 degrees, consequently 4 light sources 2 are enough completely to form 360 degrees shadows. The four light sources 2 are located in the same plane, so that the plane formed by the four light sources 2 is parallel to the surface to be measured 3, and the distances from the four light sources 2 to the center of the surface to be measured 3 are equal.
After the object to be measured is placed, the 4 light sources 2 are sequentially and independently turned on and photographed, and then the 4 obtained photos are subjected to pixel comparison, wherein the pixel comparison technology is the prior art, and for example, mvp machine vision algorithm platform software can be utilized. The purpose of pixel comparison is to select the pixel points with the deepest color in 4 pictures, combine the selected deepest pixel points into a new picture after sequentially comparing each pixel point, and identify the new picture by using a computer, thereby measuring the size of the object to be measured on the surface 3 to be measured. Because each pixel point of the synthesized picture is the darkest pixel point and the shape of the pixel point is consistent with that of the surface 3 to be detected, the pixel point is easier to identify compared with a direct photographing computer, and the probability of generating errors during identification is greatly reduced. After the size is measured, the computer sends the size information to the controller so as to facilitate the operation of the subsequent process by utilizing the size data.
As shown in FIG. 2, the included angle A between each light source 2 and the plane to be measured is preferably 20 to 60 degrees for the purpose of
Example two:
different from the first embodiment, the number of the light sources 2 is changed to two, the light sources respectively irradiate the surface to be measured 3 from the upper side and the lower side, as shown in fig. 3 to 5, fig. 3 is a photograph taken when the upper light source 2 irradiates, fig. 4 is a photograph taken when the lower light source 2 irradiates, the photographs of fig. 3 and fig. 4 are synthesized according to the above method to obtain the photograph in fig. 5, and thus it can be seen that the central angle of the shadow part irradiated by the single light source 2 hardly reaches 180 degrees, the synthesized photograph still has a part of the area with lighter color, and the probability of generating errors during computer recognition is larger than that of 4 light sources 2. But since the solution of two light sources 2 can effectively reduce the cost, it can be used in some situations where the accuracy requirement is not too high.
As shown in fig. 6, the size of the included angle a between the light source and the surface 3 to be measured has a great influence on the definition of the outline of the synthesized picture. The figure is an effect figure of photos emitted by adopting light sources with different angles aiming at objects to be measured (phi 40 mm-phi 200 mm) with different inner diameters, and as can be clearly seen from figure 6, when an included angle A between the light source and the surface to be measured 3 is too small, such as 0 degree and 15 degrees, the synthesized picture is dark, the color difference with the surrounding scene is small, the recognition threshold value is low, and the contour misjudgment is easily caused, so that the external point is recognized during measurement, and the measured value is larger than the true value; when the included angle a between the light source and the surface 3 to be measured is too large, such as 75 ° and 90 °, the contour of the surface to be measured and the inner non-surface to be measured has a high brightness value, which easily causes that the contour point cannot be identified, thereby the size value cannot be measured. Therefore, the included angle A between the light source and the surface 3 to be detected is ensured to be between 20 and 60 degrees, the computer identifies the outline of the composite picture most accurately, and the error is minimum.
The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A method for measuring the size of an inward concave object by multi-directional imaging is characterized in that: the method comprises the following steps:
s1: placing an object to be measured at an appointed photographing position, and aligning a surface to be measured with a camera at a fixed position;
s2, independently opening at least two light sources uniformly surrounding the central axis of the surface to be measured in sequence and taking pictures, wherein the at least two light sources are obliquely arranged towards the center of the surface to be measured;
s3: performing pixel comparison on at least two photos obtained in the step S2, and reserving dark pixel points;
s4: recombining and arranging the dark pixels reserved in the S3 to form a new image;
s5: the new image formed in S4 is analyzed by a computer to measure the desired size.
2. The method for measuring the size of an object having a concave shape for multi-directional imaging according to claim 1, wherein: the number of the light sources is 2-4.
3. The method for measuring the size of an object having a concave shape for multi-directional imaging according to claim 2, wherein: the number of the light sources is 4.
4. The method for measuring the size of an object having a concave shape for multi-directional imaging according to claim 1, wherein: the included angle between the irradiation direction of the light source and the surface to be measured is 20-60 degrees.
5. The method for measuring the size of an object having a concave shape for multi-directional imaging according to claim 1, wherein: the at least two light sources are located in the same vertical plane.
6. The method for measuring the dimension of an inwardly concave object for multi-directional imaging as set forth in any one of claims 1 to 5, wherein: the step S2 is completed in a dark environment.
7. The method of claim 6, wherein the step of measuring the dimension of the object comprises: further comprising S6: the computer transmits the information on the size measured in S5 to the controller.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101013028A (en) * | 2006-01-31 | 2007-08-08 | 欧姆龙株式会社 | Image processing method and image processor |
| CN101438129A (en) * | 2006-04-05 | 2009-05-20 | K·赛佩莱 | Method for measuring/recognizing shape |
| CN101536016A (en) * | 2006-09-18 | 2009-09-16 | 华盛顿大学 | Focal plane tracking for optical microtomography |
| CN103630070A (en) * | 2013-04-08 | 2014-03-12 | 苏州工业园区凯艺精密科技有限公司 | Detection method for image detector and image detector |
| JP2014137482A (en) * | 2013-01-17 | 2014-07-28 | Olympus Corp | Photographing device and photographing illumination device |
| JP2015232485A (en) * | 2014-06-09 | 2015-12-24 | 株式会社キーエンス | Image inspection device, image inspection method, image inspection program and computer readable recording medium, and apparatus having image inspection program recorded therein |
| CN108240793A (en) * | 2018-01-26 | 2018-07-03 | 广东美的智能机器人有限公司 | Dimension of object measuring method, device and system |
| CN109596058A (en) * | 2019-02-01 | 2019-04-09 | 东莞中科蓝海智能视觉科技有限公司 | Size detection and identification method for plastic workpiece |
| CN112734847A (en) * | 2021-01-15 | 2021-04-30 | 中国科学技术大学 | Multi-target optical fiber position accurate detection positioning system and method |
| CN114119779A (en) * | 2021-10-29 | 2022-03-01 | 浙江凌迪数字科技有限公司 | Method for generating material map through multi-angle polishing shooting and electronic device |
-
2022
- 2022-10-14 CN CN202211257703.3A patent/CN115655104B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101013028A (en) * | 2006-01-31 | 2007-08-08 | 欧姆龙株式会社 | Image processing method and image processor |
| CN101438129A (en) * | 2006-04-05 | 2009-05-20 | K·赛佩莱 | Method for measuring/recognizing shape |
| CN101536016A (en) * | 2006-09-18 | 2009-09-16 | 华盛顿大学 | Focal plane tracking for optical microtomography |
| JP2014137482A (en) * | 2013-01-17 | 2014-07-28 | Olympus Corp | Photographing device and photographing illumination device |
| CN103630070A (en) * | 2013-04-08 | 2014-03-12 | 苏州工业园区凯艺精密科技有限公司 | Detection method for image detector and image detector |
| JP2015232485A (en) * | 2014-06-09 | 2015-12-24 | 株式会社キーエンス | Image inspection device, image inspection method, image inspection program and computer readable recording medium, and apparatus having image inspection program recorded therein |
| CN108240793A (en) * | 2018-01-26 | 2018-07-03 | 广东美的智能机器人有限公司 | Dimension of object measuring method, device and system |
| CN109596058A (en) * | 2019-02-01 | 2019-04-09 | 东莞中科蓝海智能视觉科技有限公司 | Size detection and identification method for plastic workpiece |
| CN112734847A (en) * | 2021-01-15 | 2021-04-30 | 中国科学技术大学 | Multi-target optical fiber position accurate detection positioning system and method |
| CN114119779A (en) * | 2021-10-29 | 2022-03-01 | 浙江凌迪数字科技有限公司 | Method for generating material map through multi-angle polishing shooting and electronic device |
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