CN110849289A - Double-camera parallel confocal differential microscopic 3D morphology measurement device and method - Google Patents
Double-camera parallel confocal differential microscopic 3D morphology measurement device and method Download PDFInfo
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Abstract
The invention relates to a double-camera parallel confocal differential microscopic 3D topography measuring device and a method thereof, wherein the device comprises: the system comprises a double-camera image acquisition module, an illumination module, an optical imaging module and an image analysis and electric objective table control module; the area-array camera is used as a detector, so that the problem of low single-point and layer-by-layer scanning efficiency of the traditional laser confocal technology is solved; the micro-mirror array of the digital micro-mirror device is used as a virtual parallel pinhole to realize non-contact scanning, non-single-point scanning or layer-by-layer scanning, and after primary automatic focusing is realized, under the condition of no mechanical motion, the large-view-field microscopic 3D morphology measurement of the sample is finished through parallel confocal differential motion of the double cameras.
Description
Technical Field
The invention belongs to the field of optical microscopic imaging and microscopic surface topography measurement, and particularly relates to a double-camera parallel confocal differential microscopic 3D topography measurement device and method.
Background
The existing microscopic three-dimensional shape measurement technology has a plurality of defects, such as small detection observation range of an electronic scanning microscope and low environment anti-interference capability; the need for a large number of axial scans for optical interferometry limits the measurement efficiency of this type of method. The differential confocal measurement of the double detectors based on the traditional laser scanning confocal microscopic imaging method needs point-by-point scanning, and real-time and rapid three-dimensional measurement is difficult to realize; for example, the invention patent of Beijing university of Phytology application No. 201310026956.4 and the invention patent of Harbin university of industry application No. 201410617222.8, which achieve axial tomographic capability through pinholes and further improve axial measurement accuracy through differentiation, however, they both require a horizontal point-by-point scanning of the sample to complete three-dimensional measurement of the whole field of view, and they have the following drawbacks: when the transverse resolution point position exceeds 1 million points, the multi-point high-precision longitudinal measurement higher than 1Hz is difficult to realize. The structured light illumination microscopy can avoid point-by-point scanning in the horizontal direction, can also improve the transverse resolution capability to exceed the diffraction limit of an optical imaging system, and still needs the transverse movement of a grating to generate structured light with different phases and perform phase modulation; and the structured light is mainly used for improving the transverse optical resolution capability, and the longitudinal resolution capability of the structured light is lower than that of a conjugate pinhole scheme. For example, the invention of the iean university of transportation application No. 201510707518.3 adopts a differential method to improve the longitudinal measurement accuracy based on the phase modulation structured light imaging scheme, and the method avoids the point-by-point scanning in the horizontal direction, and the longitudinal measurement accuracy is higher than the conventional structured light method, but still has the disadvantages that firstly, the method still needs to generate the phase modulation structured light through the mechanical movement of the grating, and the efficiency is low. Secondly, the longitudinal measurement precision is difficult to realize the high precision of nanometer level. According to the existing parallel confocal measurement technology of the university of Huaqiao, which is applied to No. 201510922156X, by longitudinally moving the relative distance between a microscope objective and a sample, an area array detector is used for respectively acquiring a pair of images, namely an image before focus, on the surface of the sample in front of a focal plane, then the sample is moved to a place with an equal distance after focus, a gray level image after the focus of the sample is acquired, a differential longitudinal response curve is constructed through the difference between the two images, and the nanometer precision parallel confocal 3D measurement is realized. Although this method overcomes the problems of the conventional laser scanning confocal 3D measurement technique that requires scanning point by point in the horizontal direction and layer by layer in the longitudinal direction, this method still has the disadvantages that the sample needs to be moved to construct a 3D profile of a field of view. The method is the same as the phase modulation structured light imaging scheme, and 3D imaging of the FOV of an observation field can be completed only by staying one observation field, so that the method is not beneficial to rapid multi-field scanning of a large sample needing sub-aperture splicing and 3D appearance observation and measurement of the large sample. Therefore, there is a need for an optical measurement method to solve the above problems to achieve high precision, high efficiency, and large field range of microscopic 3D topography.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a double-camera parallel confocal differential microscopic 3D morphology measuring device and a measuring method. The device and the double-camera parallel confocal differential microscopic 3D morphology measurement method implemented on the device can realize large-field microscopic 3D morphology measurement of the sample through differential motion of the double cameras under the condition of no axial motion of the object carrying table after the sample is placed at one time; the method can realize microscopic 3D shape measurement with high transverse resolution, nano-scale measurement precision and inch-scale large-field transverse measurement range.
The technical scheme of the invention is as follows:
a double-camera parallel confocal differential microscopic 3D topography measuring device comprises a double-camera image acquisition module, an illumination module, an optical imaging module and an image analysis and electric objective table control module;
two camera image acquisition modules contain according to the light path direction of propagation in proper order: a semi-reflecting semi-transmitting spectroscope, a tube mirror and an image sensor. The semi-reflecting and semi-transmitting spectroscope divides an imaging light path into two equivalent imaging light paths, and the ideal splitting ratio of the semi-reflecting and semi-transmitting spectroscope is 50%: 50%, the difference of the allowed splitting ratio is less than 40%, and the two image sensors use an area-array camera as a detector and are respectively placed in the imaging lightEqual distance U between front of imaging focal plane and back of focal planeFAt a location; the effective photosensitive surfaces of the two image sensors are vertical to the optical axis of the imaging light path, the effective fields of view of the two image sensors are overlapped, and the overlapping degree is higher than 90%;
the illumination module comprises the following components in sequence according to the propagation direction of the light path: the device comprises an illumination light source, a condenser, a uniform light lens group, a spatial light modulator, a collimating lens, a semi-reflecting and semi-transmitting spectroscope, a microscope objective, an electric objective table and a sample placed on the objective table;
the spatial light modulator of the illumination module is arranged at a conjugate position of an object focal plane and an image focal plane of the optical imaging system, illumination light can be subdivided into a plurality of independent and mutually separated spatial array light beams to irradiate the surface of a sample, so that the accurate regulation and control of the irradiation position of the surface of the sample are realized, and the function of parallel pinholes or the function of array switchable pinholes are realized; the spatial light modulator plays a role of confocal illumination pinhole, realizes a parallel confocal role, and the confocal function improves the longitudinal resolution capability and the measurement speed, so that the parallel confocal function realizes the rapid high-precision longitudinal resolution capability.
The optical imaging module is sequentially provided with the following components in the light path transmission direction: the device comprises a sample, a microscope objective, a semi-reflecting and semi-transmitting spectroscope, a tube lens and an image sensor; the illumination module and the optical imaging module share a semi-reflecting semi-transmitting spectroscope; the optical imaging module and the double-camera image acquisition module share a semi-reflecting and semi-transmitting spectroscope and a tube lens.
The image analysis and electric objective table control module comprises a control part for controlling the initial exposure and the exposure time length of the double image sensors, an image reading part for reading image information from the double image sensors, an image processing part for performing operation processing on the image, an image display part for displaying the measured 3D morphology, and a control part for controlling the movement of the electric objective table in at least one direction.
In the illumination module, a total internal reflection lens is further included before the spatial light modulator, and is used for adjusting the angle of illumination light to meet the incidence condition of the spatial light modulator.
The illumination module further comprises a uniform light lens group for realizing uniform light illumination of the sample in a full field of view, and a core component of the uniform light lens group can be a micro lens array.
The axial positions of two image sensors of the double-camera image acquisition module can be adjusted with high precision; when they are at a distance U from the focal plane of the imaging systemBAnd UFWhen the two image sensors are zero, the output images of the two image sensors are consistent, namely the field ranges of the two image sensors and the gray-scale values of the image pixels are equal in the error allowance range.
The microscope objective can be an objective turntable comprising a plurality of objectives, when the objectives are low-numerical aperture objectives, the objectives are equal to and larger than the focal plane of the imaging system, and when the objectives are converted into high-numerical aperture objectives, the objectives are equal to and smaller than the focal plane of the imaging system; but they are always offset from the optical axis by zero distance in a direction perpendicular to the optical axis, i.e. without lateral displacement; the effective photosensitive surface is always vertical to the optical axis of the imaging light path, the field ranges of the output images of the two image sensors are kept consistent, and the contact ratio is higher than 90%. Therefore, the two image sensors can be ensured to be symmetrical about the focal plane, and the axial position can be adjusted with high precision, so as to meet the characteristic that the defocusing amount of different objective lens image spaces is different, and ensure that different defocusing amounts can be adjusted when the objective lens is switched.
The two image sensors of the double-camera image acquisition module can simultaneously acquire gray level images IF (X, Y) and IB (X, Y) with equal out-of-focus distances before and after a sample is focused at zero time difference, X is more than or equal to 0 and less than or equal to X, Y is more than or equal to 0 and less than or equal to Y, wherein X is the total line number of the gray level images, and Y is the total line number of the gray level images.
The control component can control the electric object stage to realize longitudinal Z-axis movement and horizontal X-axis and Y-axis movement, and the surface inclination degree of the electric object stage is lower than 5%.
The double-camera parallel confocal differential microscopic 3D morphology measuring device can further comprise an objective lens axial moving part, the objective lens axial moving part is connected with the objective lens and drives the objective lens to move in a high-precision mode along the optical axis direction, and the objective lens axial moving part can be a stepping motor or a piezoelectric ceramic motor.
The double-camera parallel confocal differential microscopic 3D topography measuring method realized on the double-camera parallel confocal differential microscopic 3D topography measuring device comprises the following steps:
step 4, performing difference processing on the obtained gray level images IF (x, y) and IB (x, y) with equal out-of-focus distance before and after the focus of the sample to obtain a differential longitudinal response image ID which is IF (x, y) -IB (x, y);
and 5, calculating the height Z of each position (x, y) through a pre-calibrated relation curve of the gray difference ID of the double cameras and the longitudinal height Zn, so as to restore the surface topography Z (x, y) of the sample.
Further, after the step 5, the following steps can be further included:
and 7, carrying out image splicing on the microscopic 3D surface morphologies under all the observation fields to finish the measurement of the microscopic 3D morphology with the large field.
The double-camera parallel confocal differential microscopic 3D morphology measurement method can also comprise a calibration method of a relation curve between the gray level difference ID (x, y) of the double-camera image and the longitudinal height Zn, namely a calibration step of a relation between differential longitudinal response signals and the height, and specifically comprises the following steps:
step 5.1, adjusting the axial positions of the two cameras, setting the position of one image sensor (5) at the post-focus uB, and the position of the other image sensor (9) at the pre-focus uF, wherein uB is equal to uF;
step 5.2, placing the standard height sample on an object stage, and adjusting the object stage to enable the sample to enter a measurement range of double-camera parallel confocal differential microscopic 3D morphology measurement;
step 5.3, driving an objective lens axial moving part (11) to drive a microscope objective lens (12) to carry out high-precision axial scanning, and simultaneously acquiring images of the image acquisition channels of the two cameras; recording a series of images acquired by a camera placed in a pre-focus uF as a pre-focus image series, and calling an image series acquired by a post-focus uB camera as a post-focus image series; focusing each corresponding object point (x, y) in the image series before and after focusing, and constructing characteristic curves IF (x, y) -Z, IB (x, y) -Z of the light intensity and the object surface height Z;
step 5.4, obtaining differential longitudinal response curves ID (x, y) of the IF-IB before and after focusing;
and 5.5, performing linear function fitting on the linear region of the differential curve ID to obtain a calibration curve of the relation between the gray level difference ID of the double cameras and the longitudinal height Zn.
Further, the step of calibrating the relationship between the differential longitudinal response signal and the height may further operate as follows:
and 4, performing linear function fitting on the linear region of the differential curve ID to obtain a calibration curve of the relation between the gray level difference ID of the double cameras and the longitudinal height Zn.
Compared with the existing differential microscopic 3D topography measurement technology, the invention has the following advantages:
1): the invention adopts a double-camera differential method and uses an area-array camera as a detector, thereby overcoming the problem of low single-point and layer-by-layer scanning efficiency of the traditional laser confocal technology.
2): by adopting confocal microscopy, the micro-mirror array of a digital micro-mirror device is used as a virtual parallel pinhole to realize non-contact scanning, non-single-point scanning or layer-by-layer scanning, and after one-time automatic focusing is realized, the micro 3D morphology measurement of a sample with a large view field is completed through differential motion of double cameras under the condition of no mechanical motion.
3) The method can dynamically switch between a wide-field bright field mode and a parallel confocal mode, and can realize microscopic 3D shape measurement with high transverse resolution, nano-scale measurement precision and inch-scale large-field transverse measurement range.
Drawings
Fig. 1 is a schematic diagram of a dual-camera parallel confocal differential microscopic 3D topography measuring device.
FIG. 2 is a schematic diagram of a dual-camera parallel confocal differential microscopy 3D topography measurement device with spatial light modulators.
In the figure: the system comprises a light source 1, a condenser 2, a uniform light lens group 3, a collimating lens 4, an image sensor 5, a tube lens I6, a half-reflecting and half-transmitting spectroscope I7, a tube lens II 8, an image sensor II 9, a half-reflecting and half-transmitting spectroscope II 10, an objective lens axial moving part 11, a microscope objective 12, a sample to be detected 13, an electric objective table 14, an image analysis and electric objective table control module 15, a total internal reflection lens 16 and a spatial light modulator 17.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The invention discloses a double-camera parallel confocal differential microscopic 3D morphology measuring device, which mainly comprises a double-camera image acquisition module, an illumination module, an optical imaging module, an image analysis and electric objective table control module as shown in the attached figure 1 of the specification, wherein the double-camera image acquisition module sequentially comprises the following components in the light path transmission direction: semi-reflecting semi-transparent spectroscope 7, tube mirror 6, 8, image sensor 5, 9, illumination module contains according to light path propagation direction in proper order: illumination source 1, condenser 2, even light lens group 3, collimating lens 4, half reflection semi-transparent spectroscope 10, micro objective 12, sample 13 and electronic objective table 14, the optical imaging module sets gradually according to light path propagation direction: a sample 13, a microscope objective 12, a semi-reflecting and semi-transmitting spectroscope 10, tube mirrors 6 and 8 and image sensors 5 and 9.
The following describes the present invention in further detail with reference to fig. 2.
Detailed description of the preferred embodiment
The present embodiment is an apparatus embodiment. As shown in figure 2 of the specification.
A double-camera parallel confocal differential microscopic 3D topography measuring device comprises a double-camera image acquisition module, an illumination module, an optical imaging module and an image analysis and electric objective table control module;
two camera image acquisition modules contain according to the light path direction of propagation in proper order: a semi-reflecting semi-transparent spectroscope 7, tube mirrors 6 and 8 and image sensors 5 and 9. Wherein, the semi-reflecting semi-transparent spectroscope 7 divides the imaging light path into two equivalent imaging light paths, and the ideal splitting ratio of the semi-reflecting semi-transparent spectroscope is 50%: 50 percent, the difference of the allowed light splitting ratio is less than 40 percent, the two image sensors 5 and 9 take an area array camera as a detector and are respectively arranged in front of an imaging focal plane and behind the focal plane at equal distance UFAt a location; the effective photosensitive surfaces of the two image sensors are vertical to the optical axis of the imaging light path, the effective fields of view of the two image sensors are overlapped, and the overlapping degree is higher than 90%;
the illumination module comprises the following components in sequence according to the propagation direction of the light path: the device comprises an illumination light source 1, a condenser 2, a uniform light lens group 3, a spatial light modulator 17, a collimating lens 4, a semi-reflecting and semi-transmitting spectroscope 10, a microscope objective 12, an electric objective table 14 and a sample 13 placed on the objective table;
the spatial light modulator 17 of the illumination module is arranged at a conjugate position of an object focal plane and an image focal plane of the optical imaging system, illumination light can be subdivided into a plurality of mutually independent and mutually separated spatial array light beams to irradiate the surface of a sample, the accurate regulation and control of the irradiation position of the surface of the sample are realized, and the function of parallel pinholes or the function of array switchable pinholes are realized; the spatial light modulator plays a role of confocal illumination pinhole, realizes a parallel confocal role, and the confocal function improves the longitudinal resolution capability and the measurement speed, so that the parallel confocal function realizes the rapid high-precision longitudinal resolution capability.
The optical imaging module is sequentially provided with the following components in the light path transmission direction: a sample 13, a microscope objective 12, a semi-reflecting and semi-transmitting spectroscope 10, tube lenses 6 and 8 and image sensors 5 and 9; the illumination module and the optical imaging module share a semi-reflecting semi-transmitting spectroscope 10; the optical imaging module and the double-camera image acquisition module share a semi-reflecting and semi-transmitting spectroscope 7, tube mirrors 6 and 8 and image sensors 5 and 9.
The image analysis and electric stage control module 15 includes a control unit for controlling the initial exposure and exposure time of the dual image sensor, an image reading unit for reading image information from the dual image sensor, an image processing unit for performing arithmetic processing on the image, an image display unit for displaying the measured 3D topography, and a control unit for controlling the movement of the electric stage in at least one direction.
In the illumination module, a total internal reflection lens 16 is further included before the spatial light modulator, and is used for adjusting the angle of the illumination light to meet the incidence condition of the spatial light modulator.
The illumination module further comprises a uniform light lens group 3 for realizing uniform light illumination of the sample in a full field of view, and a core component of the uniform light lens group can be a micro lens array.
The axial positions of two image sensors of the double-camera image acquisition module can be adjusted with high precision; when it is usedDistance U between people and focal plane of imaging systemBAnd UFWhen the two image sensors are zero, the output images of the two image sensors are consistent, namely the field ranges of the two image sensors and the gray-scale values of the image pixels are equal in the error allowance range.
The microscope objective 12 may be an objective turntable including a plurality of objectives, which are equally spaced and relatively spaced from the focal plane of the imaging system when the objectives are low numerical aperture objectives and equally spaced and relatively spaced from the focal plane of the imaging system when the objectives are converted to high numerical aperture objectives; but they are always offset from the optical axis by zero distance in a direction perpendicular to the optical axis, i.e. without lateral displacement; the effective photosensitive surface is always vertical to the optical axis of the imaging light path, the field ranges of the output images of the two image sensors are kept consistent, and the contact ratio is higher than 90%. Therefore, the two image sensors can be ensured to be symmetrical about the focal plane, and the axial position can be adjusted with high precision, so as to meet the characteristic that the defocusing amount of different objective lens image spaces is different, and ensure that different defocusing amounts can be adjusted when the objective lens is switched.
The two image sensors of the double-camera image acquisition module can simultaneously acquire gray level images IF (X, Y) and IB (X, Y) with equal out-of-focus distances before and after a sample is focused at zero time difference, X is more than or equal to 0 and less than or equal to X, Y is more than or equal to 0 and less than or equal to Y, wherein X is the total line number of the gray level images, and Y is the total line number of the gray level images.
The control component can control the electric object stage to realize longitudinal Z-axis movement and horizontal X-axis and Y-axis movement, and the surface inclination degree of the electric object stage is lower than 5%.
The double-camera parallel confocal differential microscopic 3D morphology measuring device further comprises an objective lens axial moving part 11, the objective lens axial moving part is connected with the objective lens and drives the objective lens to move in the optical axis direction with high precision, and the objective lens axial moving part can be a stepping motor or a piezoelectric ceramic motor.
Detailed description of the invention
This embodiment is an embodiment of a method implemented on the apparatus described in the first embodiment.
The double-camera parallel confocal differential microscopic 3D morphology measurement method comprises the following steps:
step 4, performing difference processing on the obtained gray level images IF (x, y) and IB (x, y) with equal out-of-focus distance before and after the focus of the sample to obtain a differential longitudinal response image ID which is IF (x, y) -IB (x, y);
and 5, calculating the height Z of each position (x, y) through a pre-calibrated relation curve of the gray difference ID of the double cameras and the longitudinal height Zn, so as to restore the surface topography Z (x, y) of the sample.
Further, after the step 5, the following steps can be further included:
and 7, carrying out image splicing on the microscopic 3D surface morphologies under all the observation fields to finish the measurement of the microscopic 3D morphology with the large field.
The double-camera parallel confocal differential microscopic 3D morphology measurement method can also comprise a calibration method of a relation curve between the gray level difference ID (x, y) of the double-camera image and the longitudinal height Zn, namely a calibration step of a relation between differential longitudinal response signals and the height, and specifically comprises the following steps:
step 5.1, adjusting the axial positions of the two cameras, setting the position of one image sensor (5) at the post-focus uB, and the position of the other image sensor (9) at the pre-focus uF, wherein uB is equal to uF;
step 5.2, placing the standard height sample on an object stage, and adjusting the object stage to enable the sample to enter a measurement range of double-camera parallel confocal differential microscopic 3D morphology measurement;
step 5.3, driving an objective lens axial moving part (11) to drive a microscope objective lens (12) to carry out high-precision axial scanning, and simultaneously acquiring images of the image acquisition channels of the two cameras; recording a series of images acquired by a camera placed in a pre-focus uF as a pre-focus image series, and calling an image series acquired by a post-focus uB camera as a post-focus image series; focusing each corresponding object point (x, y) in the image series before and after focusing, and constructing characteristic curves IF (x, y) -Z, IB (x, y) -Z of the light intensity and the object surface height Z;
step 5.4, obtaining differential longitudinal response curves ID (x, y) of the IF-IB before and after focusing;
and 5.5, performing linear function fitting on the linear region of the differential curve ID to obtain a calibration curve of the relation between the gray level difference ID of the double cameras and the longitudinal height Zn.
Further, the step of calibrating the relationship between the differential longitudinal response signal and the height may further operate as follows:
and 4, performing linear function fitting on the linear region of the differential curve ID to obtain a calibration curve of the relation between the gray level difference ID of the double cameras and the longitudinal height Zn.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides a two camera parallel confocal differential microscopic 3D appearance measuring device which characterized in that: the system comprises a double-camera image acquisition module, an illumination module, an optical imaging module and an image analysis and electric objective table control module;
the double-camera image acquisition module sequentially comprises the following components in the light path transmission direction: a semi-reflecting semi-transparent spectroscope (7), tube mirrors (6, 8) and image sensors (5, 9); the two image sensors (5, 9) take an area-array camera as a detector and are respectively arranged in front of an imaging focal plane and behind the imaging focal plane at equal distance UFAt a location; the effective photosensitive surfaces of the two image sensors (5 and 9) are always kept vertical to the optical axis of the imaging light path, the output image view field ranges of the two image sensors (5 and 9) are kept consistent, and the coincidence degree is higher than 90%;
the illumination module comprises the following components in sequence according to the propagation direction of the light path: the device comprises a light source (1), a condenser (2), a uniform light lens group (3), a spatial light modulator (17), a collimating lens (4), a semi-reflecting and semi-transmitting spectroscope (10), a microscope objective (12), a sample (13) and an electric objective table (14);
the core component of the uniform light lens group (3) is a micro lens array; the micro-mirror array is used as a virtual parallel pinhole;
the spatial light modulator (17) of the illumination module is arranged at the conjugate position of an object focal plane and an image focal plane of the optical imaging system, illumination light can be subdivided into a plurality of mutually independent and mutually separated spatial array light beams to irradiate the surface of a sample, the accurate regulation and control of the irradiation position of the surface of the sample are realized, and the function of parallel pinholes or the function of array switchable pinholes are realized;
the optical imaging module sequentially comprises the following components in the light path transmission direction: a sample (13), a microscope objective (12), a semi-reflecting and semi-transmitting spectroscope (10), tube mirrors (6, 8) and image sensors (5, 9); the illumination module and the optical imaging module share a semi-reflecting semi-transmitting spectroscope (10); the optical imaging module and the double-camera image acquisition module share a semi-reflecting and semi-transmitting spectroscope (7), tube mirrors (6 and 8) and image sensors (5 and 9);
the image analysis and electric objective table control module comprises a control part for controlling the initial exposure and the exposure time length of the double image sensors (5 and 9), an image reading part for reading image information from the double image sensors (5 and 9), an image processing part for performing operation processing on the image, an image display part for displaying the measured 3D morphology, and a control part for controlling the movement of the electric objective table in at least one direction.
2. The dual-camera parallel confocal differential microscopy 3D topography measurement device according to claim 1, characterized in that:
the illumination module also comprises a total internal reflection lens (16) between the spatial light modulator (17) and the uniform light lens group (3).
3. The dual-camera parallel confocal differential microscopy 3D topography measurement device according to claim 1, characterized in that: the microscope objective (12) may be an objective turret comprising a plurality of objectives; when the micro objective lens is a low-digital-aperture objective lens, the micro objective lens is equal to and larger than the focal plane of the imaging system, and when the micro objective lens is converted into a high-digital-aperture objective lens, the micro objective lens is equal to and smaller than the focal plane of the imaging system; but they are always offset from the optical axis by zero distance in a direction perpendicular to the optical axis, with no lateral displacement; the control component can control the electric object stage (14) to realize longitudinal Z-axis movement and horizontal X-axis and Y-axis movement, and the surface inclination degree of the electric object stage (14) is less than 5%.
4. The dual-camera parallel confocal differential microscopy according to claim 13D appearance measuring device, its characterized in that: the axial positions of two image sensors (5, 9) of the double-camera image acquisition module can be adjusted with high precision; when they are at a distance U from the focal plane of the imaging systemBAnd UFWhen the image signals are zero, the output images of the two image sensors (5 and 9) are consistent, and the field ranges and the image pixel gray-scale values of the two image sensors are equal in the error allowance range.
5. The dual-camera parallel confocal differential microscopy 3D topography measurement device according to claim 1, characterized in that: two image sensors (5, 9) of the double-camera image acquisition module can simultaneously acquire gray level images I with equal out-of-focus distances before and after focus of a sample at zero time differenceF(x,y)、IB(X, Y), X is more than or equal to 0 and less than or equal to X, Y is more than or equal to 0 and less than or equal to Y, wherein X is the total number of rows of the gray level image, and Y is the total number of columns of the gray level image.
6. The dual-camera parallel confocal differential microscopy 3D topography measurement device according to claim 1, characterized in that: the device also comprises an objective lens axial moving part (11), wherein the objective lens axial moving part is connected with the microscope objective lens and drives the microscope objective lens to move with high precision along the direction of the optical axis, and the objective lens axial moving part can be a stepping motor or a piezoelectric ceramic motor.
7. A double-camera parallel confocal differential microscopic 3D topography measuring method, which is characterized in that the double-camera parallel confocal differential microscopic 3D topography measuring device in claim 6 is used for measurement, and comprises the following steps:
step 9.1, placing a sample (13) to be tested on an electric objective table (14);
step 9.2, adjusting the electric objective table (14) to enable the surface of the sample to be measured to be within the measuring range of the double-camera parallel confocal differential microscopic 3D topography measuring device;
step 9.3, simultaneously obtaining gray level images I with equal out-of-focus distances before and after the sample is focused by the double-camera image acquisition moduleF(x,y)、IB(x,y)，0≤x≤X，0≤y≤Y, wherein X is the total number of rows of the gray scale image, and Y is the total number of columns of the gray scale image;
step 9.4, the gray level image I with equal out-of-focus distance before and after the focus of the obtained sample is processedF(x,y)、IB(x, y) performing difference processing to obtain a differential longitudinal response image ID＝IF(x,y)-IB(x,y)；
Step 9.5, through the pre-calibrated gray level difference I of the double camerasDAnd a longitudinal height ZnAnd (4) calculating the height Z of each position (x, y) according to the relation curve, so as to restore the surface topography Z (x, y) of the sample.
8. The dual-camera parallel confocal differential microscopy 3D topography measurement method according to claim 7, characterized in that: after step 9.5, the following steps can be included:
9.6, after the surface appearance of the sample in one view field is restored, the electric objective table (14) is controlled by the control part to move along the X axis and the Y axis in the horizontal direction, the next view field is switched to, and the operations from the step 9.3 to the step 9.5 are repeated; and if the sample surface morphology reduction is completed, performing the following operation of step 9.7:
and 9.7, carrying out image splicing on the microscopic 3D surface morphologies under all the observation fields to finish the measurement of the large-field microscopic 3D morphology.
9. The dual-camera parallel confocal differential microscopy 3D topography measurement method according to claim 7 or 8, characterized in that: the method can also comprise the step of obtaining the gray difference I of the images of the two camerasD(x, y) and a longitudinal height ZnThe relation curve calibration method, namely the step of calibrating the relation between the differential longitudinal response signal and the height, comprises the following steps:
step 11.1, adjusting the axial positions of the two cameras, and arranging an image sensor (5) after the focus uBIn front of focus u, another image sensor (9)FA position of (a) and uB＝uF；
Step 11.2, placing a standard height sample on an object stage, and adjusting the object stage to enable the sample to enter a measurement range of double-camera parallel confocal differential microscopic 3D morphology measurement;
step 11.3, driving an objective lens axial moving part (11) to drive a microscope objective lens (12) to carry out high-precision axial scanning, and simultaneously acquiring images of the image acquisition channels of the two cameras; will be placed before the coke uFThe series of images collected by the camera are recorded as a pre-focus image series and placed after focus uBThe image series collected by the camera is called as a focused image series; focusing each corresponding object point (x, y) in the image series before and after focusing to construct a characteristic curve I of light intensity and object surface height ZF(x,y)～Z，IB(x,y)～Z；
Step 11.4, mixing IF–IBObtaining the differential longitudinal response curve I before and after the focusD(x,y)；
Step 11.5, for differential curve IDThe linear region is subjected to linear function fitting to obtain the gray difference I of the two camerasDAnd a longitudinal height ZnCalibration curve of the relationship.
10. The dual-camera parallel confocal differential microscopy 3D topography measurement method according to claim 8, characterized in that: the step of calibrating the relationship between the differential signal and the height can also be operated as follows:
step 12.1, adjusting the axial positions of the two cameras, and arranging an image sensor (5) after the focus uBIn front of focus u, another image sensor (9)FA position of (a) and uB＝uF；
Step 12.2, selecting a series of standard components with known heights and increasing height equal difference, respectively placing the standard components on an object stage (14), and simultaneously acquiring images of the series of standard components by the double cameras; will be placed before the coke uFThe series of images collected by the camera are recorded as a pre-focus image series and placed after focus uBThe image series collected by the camera is called as a focused image series; focusing each corresponding object point (x, y) in the image series before and after focusing to construct a characteristic curve I of light intensity and object surface height ZF(x,y)～Z，IB(x,y)～Z；
Step 12.3, mixing IF–IBObtaining a differential curve I before and after the cokeD(x,y)；
Step 12.4, for the differential curve IDThe linear region is subjected to linear function fitting to obtain the gray difference I of the two camerasDAnd a longitudinal height ZnCalibration curve of the relationship.
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