TWI434021B - Non - contact optical composite measurement method and system - Google Patents

Description

Non-contact optical composite measuring method and system

The invention relates to an optical measuring method and system, in particular to a non-contact optical composite measuring method and system.

Measuring the surface profile of an object can be divided into two types of contact and non-contact measurement methods. The contact measurement method can obtain the measurement result because it must be in contact with the test piece to be measured. Contact will inevitably cause, for example, the risk of scratching the surface of the test piece to be measured. Therefore, the measurement of the test piece with higher surface fineness is not applicable; and with the non-contact measurement method such as optical measurement, Because it can avoid the shortcomings of the contact measurement method, it is widely used in the measurement of the test piece with high surface fineness.

The current non-contact optical measurement system is mostly a single-function design. For example, the Mirau interferometer can only measure the surface profile of the test piece, the Michelson interferometer or the phase-shifted interstitial interferometer can only be used for measurement. The amount of deformation of the test piece before and after the external force is applied.

Therefore, if it is necessary to simultaneously measure the surface profile of the test piece and the amount of deformation before and after the external force, it is necessary to prepare two kinds of measurement systems at the same time, so that in addition to the cost considerations, two different measurement systems At the same time, erection will also generate new problems. It can be seen from the above description that the current non-contact measurement method still needs to be improved, and the measurement of the surface profile and the deformation amount is simultaneously performed.

Accordingly, it is an object of the present invention to provide a non-contact optical composite measurement method that simultaneously measures the surface profile, the amount of deformation, and the amount of strain of a test piece.

Further, another object of the present invention is to provide a non-contact optical composite measuring system capable of simultaneously measuring a surface profile, a deformation amount, and a strain amount of a test piece.

Therefore, a non-contact optical composite measuring method of the present invention comprises an optical detecting system erecting step, an interference image obtaining step, and a deformation amount obtaining step.

The optical detecting system erecting step sequentially sets a light source, a collimating lens group, and a first beam splitter along a first optical axis, and defines a first light different from the first light splitting mirror as an end point. a second optical axis of the shaft, a first objective lens, a reference mirror, a second beam splitter, a second objective lens, and a photosensitive unit are sequentially disposed along the second optical axis and away from the first beam splitter The light emitted by the light source passes through the collimating lens group along the first optical axis to generate a parallel beam, and the parallel beam passes the first beam splitter, the first objective lens, and the reference plane along the first and second optical axes. The mirror and the second beam splitter are focused on a test piece to be measured, and the parallel light beam is divided by the second beam splitter into a reference light that is partially reflected by the second beam splitter and reflected by the reference mirror. And a test light reflected by the test piece after partially penetrating the second beam splitter, the reference light and the test light being focused on the photosensitive unit via the second objective lens.

The interference image obtaining step adjusts an inclination angle of the reference mirror relative to the second optical axis, so that the reference light and the test light are focused on the photosensitive unit through the second objective lens to generate an interference image, and the photosensitive unit respectively obtains the interference image a first interference image of the test piece and a second interference image.

The deformation amount obtaining step performs a silhouette operation on the first and second interference images by an image processing device to obtain a deformation amount of the test piece, and calculates a strain amount of the interference image by the image processing device to obtain a strain amount of the test piece.

In addition, a non-contact optical composite measuring system of the present invention comprises a parallel light emitting device, an optical detecting device, and an image processing device.

The parallel light emitting device includes a light source and a collimating lens group disposed at intervals along a first optical axis, such that light emitted by the light source is diverged through the collimating lens group to be parallel to the first optical axis Parallel beams.

The optical detecting device includes a first beam splitter, a first objective lens, a reference mirror, a second beam splitter, a second objective lens, and a photosensitive unit, which are sequentially disposed along a second optical axis. A parallel light beam from the parallel light emitting device is incident on the first beam splitter, and sequentially passes through the first objective lens, the reference mirror surface, and the second beam splitter to focus on a test piece to be measured, and the parallel light beam passes through the first light beam. The dichroic mirror is divided into a reference light that is reflected by the second spectroscope and reflected by the reference mirror, and a test light that is partially reflected by the second spectroscope, and the reference mirror is relatively The second optical axis adjusts the tilt angle to generate an interference image after the reference light and the test light are focused by the second objective lens on the photosensitive unit.

The image processing device digitizes the interference image captured by the photosensitive unit of the optical detecting device into digital data, and then processes and processes the digital data to obtain a surface contour, a deformation amount, and a dependent variable of the sample.

The utility model has the advantages that: by adjusting the inclination angle of the reference mirror relative to the second optical axis, the surface contour and the deformation amount of the test piece can be simultaneously obtained by the cooperation with the image processing device, and the deformation amount can be further obtained. Conversion should be In addition, the parallel light emitting device and the optical detecting device can be combined with the optical detecting device to be reduced to a portable device, and the test piece that is inconvenient to be disassembled from the machine can be directly measured, and the time for disassembling the test piece can be omitted. Relocate the test piece again to effectively improve the efficiency and accuracy of the measurement.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to Figures 1 and 2, a preferred embodiment of the non-contact optical composite measuring method of the present invention comprises an optical detecting system erecting step 11, a surface contour obtaining step 12, an interference image obtaining step 13, and a deformation amount. Step 14 is obtained for measuring the contour, deformation and strain of a test piece 5.

First, the optical detecting system erecting step 11 is performed to establish a non-contact optical composite measuring system, which comprises a parallel light emitting device 2, an optical detecting device 3, and an image processing device 4.

The parallel light emitting device 2 includes a light source 21 and a collimating lens group 22, which are sequentially disposed along a first optical axis X1, so that the light emitted by the light source 21 is diverged through the collimating lens group 22 and then parallelized. A parallel beam of light on the first optical axis X1. In this embodiment, the light source 21 is a laser device capable of emitting laser light. Preferably, the laser device can emit a 氦-氖 laser, and more preferably, an unnecessary noise is disposed. A spatial filter (not shown) to filter out noise at the desired wavelength.

The optical detecting device 3 includes a first beam splitter 31, a first objective lens 32, a reference mirror 33, a second beam splitter 34, a second objective lens 35, and a photosensitive unit 36 spaced apart along a second The optical axis X2 is sequentially disposed, and the parallel light beam from the parallel light emitting device 2 is incident on the first beam splitter 31, and then sequentially passed through the first objective lens 32, the reference mirror 33, and the second beam splitter 34. The reference beam 5 is divided by the second beam splitter 34 into a reference light 37 which is partially reflected by the second beam splitter 34 and reflected by the reference mirror 33, and partially penetrates the second light. After the beam splitter 34, the test piece 5 reflects a test light 38, and the reference mirror 33 can adjust the tilt angle with respect to the second optical axis X2, so that the reference light 37 and the test light 38 are focused by the second objective lens 35. The photosensitive unit 36 generates an interference image. In this embodiment, the photosensitive unit 36 is a charge coupled component; in addition, the first and second objective lenses 32 and 35 can be matched with different multiples of optical depending on the geometric shape, size, and surface roughness of the test piece 5. Lens for better measurement results.

The image processing device 4 includes an image capturing unit 41 and a digital data processing unit 42. The image capturing unit 41 digitizes the interference image captured by the photosensitive unit 36 of the optical detecting device 3 into digital data. The processing program 42 calculates and processes the digital data to obtain the surface contour and the deformation amount of the test piece 5, and then obtains the strain amount from the deformation amount (this process will be described later in detail). In this embodiment, the image processing apparatus 4 is a computer having the image capturing unit 41 and the digital data processing program 42.

After the optical detection system erection step 11 is performed, the surface contour obtaining step 12 is performed, the light source 21 of the parallel light emitting device 2 is turned on, and the light is emitted. After exiting the 氦-氖 laser, the collimating lens group 22 is diverged to form a parallel beam, and the parallel beam is incident on the optical detecting device 3, and then divided into the reference light 37 and the test light 38 via the second beam splitter 34, and then the adjustment is performed. The angle of inclination of the reference mirror 33 with respect to the second optical axis X2 is to change the optical path difference between the reference light 37 and the test light 38. When the optical path difference is met and the interference fringe appears, the position of the surface of the test piece 5 is recorded. The tilt angle of the reference mirror 33 is calculated by the image processing device 4 to eliminate the height influence caused by the tilt angle of the reference mirror 33, and then the height of the surface of the test piece 5 can be obtained, and then the test piece is obtained. The surface contour of the test piece 5 can be drawn by the matching of the positions of the surfaces.

Next, the interference image obtaining step 13 is performed. After the parallel light beam emitted from the light source 21 of the parallel light emitting device 2 is incident on the optical detecting device 3, the parallel light beam is divided into the reference light 37 and the test light by the second beam splitter 34. 38, adjusting the tilt angle of the reference mirror 33 relative to the second optical axis X2, so that the reference light 37 and the test light 38 are focused on the photosensitive unit 36 via the second objective lens 35 to generate interference images at two different time points; In this example, the angle of inclination of the reference mirror 33 of the optical detecting device 3 with respect to the second optical axis X2 is adjusted, and the first interference image before the specimen 5 is affected by heat or other external force is obtained by the photosensitive unit 36, respectively. As shown in Annex 1, and the second interference image of the test piece 5 after being affected by heat or other external force, as shown in Annex 2.

Then, the amount of deformation is obtained in step 14. The image capturing unit 41 digitizes the first and second interference images captured by the photosensitive unit 36 of the optical detecting device 3 into digital data, and then performs the digital data processing program 42. Silhouette technique, obtain the image subtraction map as shown in Annex 3, and then calculate the distribution and number of interference fringes after subtraction of the image, and calculate the ordinal number of the interference fringe The deformation amount of the test piece can be obtained, and after the deformation amount is obtained, the deformation amount is subjected to partial differential calculation in the selected direction, and the strain amount of the test piece 5 is obtained.

In addition, this step can also introduce a phase shift method by installing a liquid crystal phase modulator to improve the accuracy of calculating interference fringes. In addition, those skilled in image processing technology can also apply existing image processing. The technique enhances the image so that the sharpness of the resulting interference fringes is increased to more accurately calculate the interference fringe number. Since the techniques of image processing are not the focus of the present invention, they will not be described in detail.

As can be seen from the above description, the present invention forms an interference image on the photosensitive unit 36 by the test piece 5 to be measured by the parallel light emitting device 2 and the optical detecting device 3, and the light path has no special length limitation, and then the image processing is performed. The interference image calculated by the device 4 is used to know the outline, the deformation amount and the strain amount of the test piece. Therefore, the parallel light emitting device 2 and the optical detecting device 3 can be designed into a portable small-scale optical measurement according to actual needs. The equipment can be directly erected to the test piece on-site to instantly measure and instantly synchronize the shape, deformation and strain of the test piece 5 during the machining operation.

It should be noted that the surface profile and the deformation amount of the test piece 5 can be measured or measured simultaneously according to requirements, that is, after the optical detecting system erection step 11 is completed, the surface contour is obtained to obtain step 12, and The surface contour of the test piece 5, or the interference image is obtained to obtain the step 13 and the deformation amount is obtained in step 14. The deformation amount of the test piece 5 before and after being affected by heat or other external force is obtained, or the surface contour is sequentially obtained. Step 12, the interference image is obtained in step 13, and the deformation amount is obtained in step 14. At the same time, the surface contour and the deformation amount of the test piece 5 are obtained, and the amount of deformation is obtained from the deformation amount.

In summary, the non-contact optical composite measuring method of the present invention is an optical measuring method for simultaneously measuring the surface contour and the deformation amount of the test piece 5, and applying the existing image processing technique to enhance the image, so that The sharpness of the interference fringes is increased. If the test piece 5 requires a finer measurement accuracy requirement, after the phase shift method is introduced, the measurement accuracy can be greatly improved to more accurately calculate the interference fringe number, and according to the test piece 5 The actual measurement requirement, at the same time, obtains the surface profile and deformation amount of the test piece 5, or the surface profile and the deformation amount, and the measurement is not only for the surface profile or the deformation amount of the test piece 5, There is no need to set up another optical system.

The non-contact optical composite measuring system of the present invention achieves the same effect as the existing Mirau interferometer by adjusting the tilt angle of the reference mirror 33 with respect to the second optical axis X2, that is, measuring a test to be measured. The surface contour of the member 5 is obtained. In addition, the first and second interference images of the test piece 5 before and after being affected by heat or other external force are obtained by the photosensitive unit 36, and the image processing device 4 performs image processing to calculate the to-be-measured image. The deformation amount of the test piece 5 is further determined by the amount of deformation, and the surface profile, the deformation amount, and the strain amount of the test piece 5 are simultaneously measured by a single non-contact optical composite measurement system.

Furthermore, it can be seen from the above description that the non-contact optical composite measuring system of the present invention has no special length limitation due to the optical path, and the entire measuring process does not need to move or contact the test piece to be tested, so it can be adapted to actual needs. It is designed as a portable small-scale optical measuring equipment, which can be directly placed on the test piece to be built on the site for real-time measurement and instant synchronization. The shape, deformation and strain of the test piece in the machining operation are known, which is inconvenient for the machine to be disassembled. Test piece, province The time to disassemble the test piece and the problem of repositioning the test piece effectively improve the efficiency and accuracy of the measurement, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

11‧‧‧ Optical inspection system erection steps

12‧‧‧ Surface contour steps

13‧‧‧Interference image acquisition steps

14‧‧‧Deformation step

2‧‧‧Parallel light emitting device

21‧‧‧Light source

22‧‧‧ collimating lens group

3‧‧‧Optical inspection device

31‧‧‧First Beamsplitter

32‧‧‧First objective

33‧‧‧ reference mirror

34‧‧‧Second beam splitter

35‧‧‧Second objective

36‧‧‧Photosensitive unit

4‧‧‧Image processing device

41‧‧‧Image capture unit

42‧‧‧Digital Data Processing Program

5‧‧‧ test pieces

X1‧‧‧first optical axis

X2‧‧‧second optical axis

1 is a flow chart illustrating a preferred embodiment of the non-contact optical composite measurement method of the present invention; and FIG. 2 is a schematic view showing a non-contact optical composite measurement when the preferred embodiment of the present invention is implemented system.

[A brief description of the attachment]

Attachment 1 is an image diagram illustrating the first interference image before the deformation of the test piece; Annex 2 is an image view illustrating the second interference image after the deformation of the test piece; and Annex 3 is an image view illustrating the silhouette The result of subtracting the first and second interference images of the test piece is performed.

2. . . Parallel light emitting device

twenty one. . . light source

twenty two. . . Collimating lens group

3. . . Optical detection device

31. . . First beam splitter

32. . . First objective

33. . . Reference mirror

34. . . Second beam splitter

35. . . Second objective

36. . . Photosensitive unit

4. . . Image processing device

41. . . Image capture unit

42. . . Digital data processing program

5. . . Specimen

X1. . . First optical axis

X2. . . Second optical axis

Claims (9)

A non-contact optical composite measuring method includes: an optical detecting system erecting step of sequentially setting a light source, a collimating lens group, and a first beam splitter along a first optical axis, and using the first The beam splitter defines a second optical axis different from the first optical axis, and a first objective lens, a reference mirror, a second beam splitter, a second objective lens, and a photosensitive unit are sequentially a second optical axis is disposed away from the first beam splitter, and the light emitted by the light source passes through the collimating lens group along the first optical axis to generate a parallel beam, and the parallel beam passes through the first and second optical axes. The first beam splitter, the first objective lens, the reference mirror, and the second beam splitter are then focused on a test piece to be measured, and the parallel beam is divided into portions by the second beam splitter by the second beam splitter a reference light reflected from the reference mirror, and a test light reflected by the test piece after partially penetrating the second beam splitter, the reference light and the test light being focused on the photosensitive unit via the second objective lens; An interference image obtaining step of adjusting the reference mirror relative to the second An angle of inclination of the axis, the reference light and the test light are focused on the photosensitive unit by the second objective lens to generate an interference image, wherein the photosensitive unit respectively obtains a first interference image of the test piece and a second interference image And a deformation amount obtaining step, wherein the first and second interference images are subjected to a silhouette operation by an image processing device to obtain a deformation amount of the test piece, and the image processing device calculates a stripe number of the interference image to obtain the test piece. strain. Non-contact composite measurement method according to item 1 of the patent application scope The light source used in the erection step of the optical detection system is a laser device that emits laser light. The non-contact composite measuring method according to claim 1, wherein the photosensitive unit used in the optical detecting system erecting step is a charge coupled device. The non-contact composite measuring method according to claim 1, wherein the image processing device used in the step of obtaining the deformation has an image capturing unit that digitizes the image captured by the photosensitive unit into digital data. And an arithmetic processing digital data to obtain a surface contour, a deformation amount of the test piece, and a digital data processing program of the dependent variable. The non-contact composite measuring method according to claim 1, further comprising a surface contour obtaining step of eliminating a height difference caused by the tilt angle of the reference mirror according to the interference image obtained by the photosensitive unit The surface profile of the test piece was obtained. A non-contact optical composite measuring system comprises: a parallel light emitting device, comprising a light source, and a collimating lens group, arranged at intervals along a first optical axis, so that the light emitted by the light source passes through the quasi-alignment The straight lens group is diverged to form a parallel beam parallel to the first optical axis; an optical detecting device includes a first beam splitter, a first objective lens, a reference mirror, a second beam splitter, and a second objective lens. And a photosensitive unit, which is sequentially disposed along a second optical axis, and the parallel light beam from the parallel light emitting device is incident on the first beam splitter, and sequentially passes through the first objective lens, the reference mirror surface, and the second splitting light. The mirror is focused on a measurement In the test piece, the parallel beam is divided by the second beam splitter into a reference light that is reflected by the second beam splitter to the reference mirror, and is reflected by the test piece after partially penetrating the second beam splitter. a test light, the reference mirror can adjust the tilt angle relative to the second optical axis, so that the reference light and the test light are focused on the photosensitive unit through the second objective lens to generate an interference image; and an image processing device, digitizing After the interference image captured by the photosensitive unit of the optical detecting device is digitized, the digital data is processed and processed to obtain the surface contour, the deformation amount, and the dependent variable of the test piece. The non-contact optical composite measuring system according to claim 6, wherein the light source of the parallel light emitting device is a laser device capable of emitting laser light. The non-contact optical composite measuring system according to claim 6, wherein the photosensitive unit of the optical detecting device is a charge coupled device. According to the non-contact optical composite measuring system of claim 6, the image processing device has an image capturing unit that digitizes the image captured by the photosensitive unit into digital data, and an arithmetic processing digital data is obtained. The surface contour of the test piece, the amount of deformation, and the digital data processing program of the strain.