CN110927181A

CN110927181A - Method for detecting foreign matters in part hole, terminal device and computer-readable storage medium

Info

Publication number: CN110927181A
Application number: CN201911109243.8A
Authority: CN
Inventors: 王海川; 刘艳华; 张智颢; 郭曙光; 代祥松; 李鹏
Original assignee: Shenzhen Certainn Technology Co Ltd
Current assignee: Shenzhen Moting Medical Technology Co ltd
Priority date: 2019-11-13
Filing date: 2019-11-13
Publication date: 2020-03-27
Anticipated expiration: 2039-11-13
Also published as: CN110927181B

Abstract

The invention provides a method for detecting foreign matters in a part hole, terminal equipment and a computer readable storage medium, wherein the method comprises the following steps: emitting a light beam to the surface inside the hole of the part to be measured through an OCT measuring unit, and carrying out optical coherence tomography to obtain a tomogram in the hole of the part to be measured; processing the fault map to obtain the positions of the orifice and the bottom of the hole of the part to be detected; and determining a foreign matter detection result according to the thickness of the bottom of the hole. The OCT measurement unit emits light beams to the surface inside the hole of the part to be measured, optical coherence tomography is carried out to obtain a tomogram in the hole of the part to be measured, then the tomogram is processed, whether foreign matters exist or not is judged according to the thickness of the bottom of the hole, micron-sized foreign matters can be detected, the accuracy is high, and the efficiency is high.

Description

Method for detecting foreign matters in part hole, terminal device and computer-readable storage medium

Technical Field

The invention relates to the technical field of image processing, in particular to a method for detecting foreign matters in a part hole, terminal equipment and a computer-readable storage medium.

Background

In industrial processes, scrap iron (micron-scale) remains in machining processes and special processes are used to process samples, so foreign materials may be present in the holes of the parts and may affect later use of the samples (e.g., lock screws, interference with signals in the samples). In the prior art, manual detection is performed by using a microscope, so that a large amount of labor cost is consumed, and the subjectivity is high; even if the equipment is adopted for auxiliary inspection, the precision is not high, and the actual requirement cannot be met.

Disclosure of Invention

The invention provides a method for detecting foreign matters in a part hole, aiming at solving the existing problems.

In order to solve the above problems, the technical solution adopted by the present invention is as follows:

a method for detecting foreign matters in a part hole comprises the following steps: s1: emitting a light beam to the surface inside the hole of the part to be measured through an OCT measuring unit, and carrying out optical coherence tomography to obtain a tomogram in the hole of the part to be measured; s2: processing the fault map to obtain the positions of the orifice and the bottom of the hole of the part to be detected; s3: and determining a foreign matter detection result according to the thickness of the bottom of the hole.

Preferably, processing the tomogram includes: s21: segmenting the tomogram to obtain a transition segmentation image; s22: in the transition segmentation image, the connected region with the largest area is returned to zero, and other regions are returned to a non-zero numerical value to obtain a binary image; s23: adding 10-20 pixels which are transversely adjacent in the binary image to obtain two peaks, wherein the two peaks from top to bottom are respectively an orifice and a hole bottom, and confirming the positions of the orifice and the hole bottom in the binary image.

Preferably, the tomogram is used for segmenting dissimilarity and position information of the integrated image, and an adaptive threshold is determined according to intra-class differences and inter-class differences.

Preferably, step S3 includes the steps of: s31: obtaining the thickness of the hole bottom in the binary image; s32: comparing the thickness of the bottom of the hole to a standard thickness; s33: and if the thickness of the hole bottom exceeds the standard thickness, the hole bottom has foreign matters.

Preferably, the light source emits visible light or infrared light outwards; the foreign matters comprise rust and residual glue.

Preferably, the beam contains at least 10 lines of radiation.

Preferably, the beam contains 36 rays.

Preferably, the foreign matter is determined when the thickness of the bottom of the hole exceeds 25 pixels.

The invention also provides a part hole foreign matter detection terminal device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and is characterized in that the processor implements the steps of any one of the methods when executing the computer program.

The invention further provides a computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, carries out the steps of the method as set forth in any of the above.

The invention has the beneficial effects that: the method comprises the steps of emitting a light beam to the surface inside a part hole to be detected through an OCT (optical coherence tomography) measuring unit, carrying out optical coherence tomography to obtain a fault map in the part hole to be detected, processing the fault map, judging whether foreign matters exist according to the thickness of the bottom of the hole, detecting the foreign matters in a micron order, and having high precision, high accuracy and high efficiency.

Drawings

Fig. 1 is a schematic diagram of an OCT measurement apparatus according to the prior art in an embodiment of the present invention.

Fig. 2 is a schematic diagram of a body module in an embodiment of the invention.

FIG. 3 is a schematic diagram of a method for detecting a foreign object in a hole of a component according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a method for processing a fault map in a hole of a part according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a method for determining a foreign object detection result according to the thickness of the bottom of the hole in the embodiment of the present invention.

FIG. 6 is a schematic view of a fault in a hole of a part having a foreign object in an embodiment of the present invention.

FIG. 7 is a schematic illustration of a ray scan in an embodiment of the invention.

FIG. 8 is a diagram illustrating image segmentation according to an embodiment of the present invention.

FIG. 9 is a schematic diagram of a pixel in an embodiment of the invention.

FIG. 10 is a schematic illustration of a resulting image over-segmented in an embodiment of the invention.

FIG. 11 is a diagram illustrating an embodiment of an image after bisection.

FIG. 12 is a schematic diagram of a transversely summed image in an embodiment of the invention.

FIG. 13 is a schematic diagram of an embodiment of the present invention in which the bottom of the hole has residual glue and the image is divided into two parts and then processed.

FIG. 14 is a schematic diagram of an image processed after dividing a hole bottom into two parts and having a foreign object at the bottom of the hole according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. In addition, the connection may be for either a fixing function or a circuit connection function.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

Optical coherence tomography is the acquisition and processing of tomographic images using optical signals. The device can scan optical scattering media such as biological tissues and the like, the resolution of the obtained three-dimensional image can reach the micron level, and the structure of a transparent object can be better detected. Optical coherence tomography uses the principle of light interference, usually uses near-infrared light to take pictures, and can control the depth of the light passing through the scanning medium by changing the wavelength of the light. Optical coherence tomography can obtain surface and sub-surface images of transparent or opaque substances, the resolution of the images is the same as that of a miniature microscope, and currently, optical coherence tomography is widely used for high-resolution imaging of retina and front end of eye in the field of ophthalmology.

The general optical coherence tomography is used for detecting back reflection or several times of scattering signals of incident weak coherent light at different depth levels of biological tissues, and two-dimensional or three-dimensional structural images of the biological tissues can be obtained through scanning.

As shown in fig. 1, the OCT measurement device in the prior art is used for measuring parameters of a human eye 200, such as axial length of an eye, length of a lens, and the like of the human eye 200, and the ophthalmic measurement device includes a main body module 10, a scanning component 20, an anterior ocular segment optical path component 30, a posterior ocular segment optical path component 40, an adjusting component 50, a beam splitter and an ophthalmoscope (not shown in the figure), the main body module 10 generates reference light and provides the scanning component 20 with light, the light is transmitted to the anterior ocular segment optical path component 30 or the posterior ocular segment optical path component 40 according to a rotation angle of the scanning component 20, and is focused to a corresponding portion of the human eye 200 by the adjusting component 50, the beam splitter and the ophthalmoscope to form signal light, the signal light propagates back to the main body module 10 in a direction opposite to an incident light and interferes with the reference light to generate interference light, the body module 10 also collects the interference light.

As shown in fig. 2, the body module 10 includes a light source 11, a coupler 12, a reference lens 13, a reference mirror 14, a polarization controller 15, a focusing lens 16, a detector 17, and a controller 18. The light source 11 may be an OCT light source, which emits weak coherent light with a wavelength of near infrared and transmits the light to the coupler 12, and the coupler 12 splits the received light into two beams, wherein one beam is collimated by the reference lens 13 and vertically reflected by the reference mirror 14 and then returns to the coupler 12 as reference light. The other beam is focused by the polarization controller 15 and the focusing lens 16 and then transmitted to the scanning assembly 20.

The adjusting element 50 receives the light from the anterior segment optical path assembly 30, and reflects the light to the beam splitter, and then reflects the light by the beam splitter 60 and focuses the light on the anterior segment of the human eye 200, such as the cornea of the human eye 200, through the ophthalmoscope 70. The anterior ocular segment scatters incident light to generate an anterior ocular segment light signal, the anterior ocular segment light signal is transmitted back to the main body module 10 through the ophthalmoscope, the spectroscope, the adjusting element 50, the anterior ocular segment light path component 30 and the scanning component 20 in sequence along a direction opposite to the original incident light, and interferes with the reference light in the coupler 12 to generate interference light, and the detector 17 receives the interference light, processes the interference light and transmits the interference light to the controller 18. Since the polarization direction of the signal light at the anterior segment is controlled by the polarization controller 15 before returning to the coupler 12, the effect of interference is ensured.

After the light is focused to the posterior segment of the human eye 200, the posterior segment scatters the incident light and generates a posterior segment light signal, the posterior segment light signal is transmitted back to the main body module 10 through the ophthalmoscope 70, the spectroscope 60, the adjusting element 50, the posterior segment light path component 40 and the scanning component 20 in sequence along the direction opposite to the original incident light, and interferes with the reference light in the coupler 12 to generate interference light, and the detector 17 receives and processes the interference light and transmits the interference light to the controller 18. Since the polarization direction of the eye posterior segment signal light is controlled by the polarization controller 15 before returning to the coupler 12, the interference effect is ensured. The controller 18 can obtain the corresponding human eye parameters through the optical path difference between the anterior segment imaging and the posterior segment imaging.

The invention creatively applies the optical coherence tomography to the detection of the foreign matters in the part holes by using the principle and the hardware unit, and adopts the OCT measurement unit to detect the foreign matters in the part holes, thereby improving the precision and the accuracy of the detection of the foreign matters in the part holes. The details are as follows.

As shown in fig. 3, a method for detecting foreign matters in a part hole comprises the following steps:

s1: two beams of light are emitted outwards through a light source, one beam of sample light is emitted to the surface inside the hole of the part to be detected, the other beam of reference light is emitted to a reference reflector, and optical coherence tomography imaging is carried out to obtain a tomogram in the hole of the part to be detected;

s2: processing the fault map to obtain the positions of the orifice and the bottom of the hole of the part to be detected;

s3: and determining a foreign matter detection result according to the thickness of the bottom of the hole.

It will be appreciated that the component of the invention may be a screw or the like for a cell phone with a hole in the middle.

In an embodiment of the present invention, the light source emits visible light or infrared light, and it is understood that light of different wavelength bands can be selected according to the type of the component, and the final effect is preferably selected.

Performing radioactive ray scanning by adopting optical coherence tomography imaging; in the prior art, the OCT equipment is 840nm +/-50, and can also be optical infrared rays with other wavelengths. In one embodiment of the invention, aiming at the screw size, the hole diameter is 0.75 mm-1.2 mm, the depth is 1.2-2.1 mm, the detected foreign bodies mainly comprise residual scrap iron, dust, residual glue and the like, and the size of the foreign bodies is in a micron scale. Each pixel in the obtained image represents 7 micrometers, and the detection precision is about tens of micrometers. At least 10 radioactive rays are emitted.

As shown in fig. 4, processing the tomogram includes:

s21: segmenting the tomogram to obtain a transition segmentation image;

s22: in the transition segmentation image, the connected region with the largest area is returned to zero, and other regions are returned to a non-zero numerical value to obtain a binary image;

s23: adding 10-20 pixels which are transversely adjacent in the binary image to obtain two peaks, wherein the two peaks from top to bottom are respectively an orifice and a hole bottom, and confirming the positions of the orifice and the hole bottom in the binary image.

And the fault map is used for segmenting the dissimilarity and the position information of the comprehensive image, and an adaptive threshold is determined according to the intra-class difference and the inter-class difference.

As shown in fig. 5, step S3 includes the following steps:

s31: obtaining the thickness of the hole bottom in the binary image;

s32: comparing the thickness of the bottom of the hole to a standard thickness;

s33: and if the thickness of the hole bottom exceeds the standard thickness, the hole bottom has foreign matters.

In one embodiment of the invention, a thickness of the bottom of the hole exceeding 25 pixels determines that foreign matter is present.

Example 2

As shown in fig. 6, in the industrial process, some scrap iron (micron level) may remain in the machining process and some special processes may be used to process the sample, so that some foreign matters may exist in the hole of the part, which may affect the later use of the sample (e.g. affect the locking screw and interfere with the signal in the sample). Optical coherence tomography is used for obtaining cross-sectional images and can be used for detecting information inside the screw. OCT may reflect foreign objects multiple times, and thus the imaged foreign object may be on the lower portion of the screw.

The technology applies the imaging technology in the field of medical imaging to the detection of foreign matters in the part hole for the first time. First, light is focused on the surface of the sample (screw) to be measured and the reflected light is mixed with reference light to produce an interference pattern about the sample information, which corresponds to a simple a-scan, since it scans only the Z-axis. Scanning of the sample may be achieved by moving the light impinging on the sample or by moving the sample. The line scan produces a two-dimensional data set corresponding to a cross-section of the sample (screw) (X-Z axis scan), while the area scan produces a three-dimensional data set corresponding to a volumetric image (X-Y-Z axis scan), also known as full field optical coherence tomography.

The galvanometer is an excellent vector scanning device. The motor is a special oscillating motor, the basic principle is that a coil generates moment in a magnetic field, a rotor of the motor is added with reset moment by a mechanical spring or an electronic method, the magnitude of the reset moment is in direct proportion to the angle of the rotor deviating from a balance position, when the coil is electrified with certain current and the rotor deflects to a certain angle, the magnitude of the electromagnetic moment is equal to that of the reset moment, so that the motor cannot rotate like a common motor and can only deflect, the deflection angle is in direct proportion to the current and is the same as a galvanometer, and therefore, the galvanometer is called a galvanometer scanning galvanometer. The scanning angle of the galvanometer can be controlled by controlling the current, so that the imaging position of oct (X-Z section) can be controlled. The device adopts 36 radioactive ray scans to obtain a fault map (shown in figure 1) of the section (X-Z section) of the part hole, and then judges whether foreign matters exist in the part hole by using an algorithm.

First, as shown in fig. 7, 36 line radiation scans were performed for each part hole, and 36 sets of sectional images were obtained.

And secondly, identifying foreign matters such as residual glue and the like. As shown in fig. 8, first, the image is divided. The vertex set comprises vertex sets V (vertexes) and edge sets E (edges), wherein G is (V, E), the vertex V belongs to V, namely, the vertex is a single pixel point, and edges (vi, vj) connecting a pair of vertexes have weights w (vi, vj), meaning dissimilarity (dissimilarity) between the vertexes. The circles in fig. 8 represent vertices and the lines where circles are directly connected represent edges (weights).

Graph-based image segmentation is employed, which integrates dissimilarity and location information of the image. In contrast to using the global threshold alone, to perform a binary of the image, graph segmentation determines an adaptive threshold based on intra-class differences and inter-class differences.

The method comprises the following specific steps: 1. calculating the dissimilarity of each pixel point and the 8 neighborhoods thereof, for example, if the calculation is performed in the sequence from left to right and from top to bottom as an undirected graph in fig. 9, only the line connected in the graph needs to be calculated;

2. arranging the edges from small to large according to the dissimilarity ei to obtain e1, e 2.., en;

3. selecting a dissimilarity ei;

4. and carrying out merging judgment on the currently selected edges ej (vi and vj do not belong to one region). Let the vertex to which it is connected be (vi, vj)

if dissimilarity is less than internal dissimilarity

5. Updating thresholds and class labels

else：

6. And if i is less than n, selecting the next edge to turn to Step 4 according to the sorted sequence, and if not, ending. After the operation is completed, fig. 10 can be obtained.

Then, by zeroing the connected region having the largest area and the other regions to 255(255 is the maximum value of the 8-dimensional binary image), fig. 11 can be obtained.

As shown in fig. 12, the subsequent addition of the laterally adjacent 15 pixels of the image results in two peaks from which the position of the hole and the bottom of the hole can be determined.

The aperture and the bottom of the hole, as shown in fig. 13 and 14, can be used to locate the hole, and the glued image of the bottom of the hole has a much greater thickness than the normal bottom of the hole. Finally, a threshold (25-35 pixels) is set for the thickness of the bottom of the hole, and the image larger than the threshold can judge that the bottom of the hole is abnormal.

And thirdly, integrating the image processing results of 36 line scanning. One of the images has an anomaly, and the part hole is abnormal.

Example 3

The part hole foreign matter detection terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor, such as a program for acquiring an image. The processor, when executing the computer program, implements the steps of the above-described embodiments of the method for detecting foreign matter in a hole in a part, such as steps S1-S3 shown in fig. 1. Alternatively, the processor implements the functions of the modules/units in the above device embodiments when executing the computer program.

Illustratively, the computer program may be partitioned into one or more modules/units that are stored in the memory and executed by the processor to implement the invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used for describing the execution process of the computer program in the foreign matter detection terminal equipment in the part hole. For example, the computer program may be divided into an image acquisition module, an image processing module, and a detection result acquisition module, and the specific functions of each module are as follows: the method comprises the steps that infrared rays are emitted to the surface inside a hole of a part to be detected, and a fault map in the hole of the part to be detected is obtained; processing the fault map to obtain the positions of the orifice and the bottom of the hole of the part to be detected; and determining a foreign matter detection result according to the thickness of the bottom of the hole.

The foreign matter detection terminal equipment in the part hole can be computing equipment such as a desktop computer, a notebook computer, a palm computer and a cloud server. The foreign matter detection terminal equipment in the part hole can comprise, but is not limited to, a processor and a memory. It will be understood by those skilled in the art that the schematic diagram is merely an example of the foreign object detection terminal device in the part hole, and does not constitute a limitation of the foreign object detection terminal device in the part hole, and may include more or less components than those shown, or some components in combination, or different components, for example, the foreign object detection terminal device in the part hole may further include an input-output device, a network access device, a bus, etc.

The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general processor can be a microprocessor or the processor can be any conventional processor and the like, the processor is a control center of the foreign matter detection terminal equipment in the part hole, and various interfaces and lines are utilized to connect various parts of the foreign matter detection terminal equipment in the whole part hole.

The memory can be used for storing the computer program and/or the module, and the processor realizes various functions of the foreign matter detection terminal equipment in the part hole by running or executing the computer program and/or the module stored in the memory and calling the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.

The module/unit integrated with the foreign matter detection terminal device in the part hole can be stored in a computer readable storage medium if it is realized in the form of a software functional unit and sold or used as an independent product. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several equivalent substitutions or obvious modifications can be made without departing from the spirit of the invention, and all the properties or uses are considered to be within the scope of the invention.

Claims

1. A method for detecting foreign matters in a part hole is characterized by comprising the following steps:

s1: emitting a light beam to the surface inside the hole of the part to be measured through an OCT measuring unit, and carrying out optical coherence tomography to obtain a tomogram in the hole of the part to be measured;

2. The method for detecting foreign matter in a part hole according to claim 1, wherein processing the tomogram includes:

s21: segmenting the tomogram to obtain a transition segmentation image;

3. The method for detecting foreign matter in a part hole according to claim 2, wherein the tomogram divides the dissimilarity and positional information of the integrated image, and determines an adaptive threshold value based on the intra-class difference and the inter-class difference.

4. The method for detecting foreign matter in a component hole according to claim 2, wherein step S3 includes the steps of:

s31: obtaining the thickness of the hole bottom in the binary image;

s32: comparing the thickness of the bottom of the hole to a standard thickness;

s33: and if the degree of the bottom of the hole exceeds the standard thickness, the bottom of the hole has foreign matters.

5. The method for detecting foreign matter in a component hole according to claim 1, wherein the light beam is visible light or infrared light; the foreign matters comprise rust and residual glue.

6. The method of detecting foreign matter in a component hole of claim 5, wherein said light beam contains at least 10 lines of radiation.

7. The method of detecting foreign matter in a component hole of claim 6, wherein said light beam includes 36 rays.

8. The method of claim 1, wherein the presence of a foreign object is determined when the thickness of the bottom of the hole exceeds 25 pixels.

9. A component hole foreign object detection terminal device comprising a memory, a processor and a computer program stored in said memory and executable on said processor, wherein said processor when executing said computer program implements the steps of the method according to any one of claims 1 to 8.

10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 8.