A device and method for measuring motion posture of astronomical film scanner

Abstract

The present invention provides a device for measuring the motion posture of an astronomical film scanner, comprising an astronomical film scanner to be measured, and a photoelectric autocollimator and a target device arranged relative to each other, wherein the target device comprises a plane wedge mirror and a three-dimensional adjustment mechanism connected to the plane wedge mirror and the motion platform of the astronomical film scanner. The present invention also provides a method for measuring the motion posture of an astronomical film scanner. The device and method for measuring the motion posture of an astronomical film scanner of the present invention solve the problem that the three-dimensional motion posture of an astronomical film scanner cannot be measured simultaneously, and realize the simultaneous measurement of the motion posture.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and in particular relates to a device and method for measuring the motion posture of an astronomical film scanner, which is suitable for measuring the motion posture of an astronomical film scanner. Background Art

[0002] Cameras are now widely used in telescope imaging. In the early years, before cameras were developed, telescopes were photographed using astronomical films, which were relatively large in size: mostly 300mm×300mm; but astronomical films are long-term observation data, which record the position and activity information of celestial bodies for more than 100 years, and are the only irreproducible observation record of the celestial bodies photographed at that time. Astronomical films are difficult to preserve and are easily damaged, so they need to be digitized and preserved.

[0003] The digitization of astronomical film is to image several small areas of a large-sized astronomical film on the camera target surface through the platform scanning movement using the imaging lens, and finally stitch the images of multiple groups of imaging units in a certain order and processing method to restore them into a large-sized astronomical film to achieve digital preservation. Astronomical film scanner is a special instrument used to scan astronomical film to realize the digitization of astronomical film.

[0004] Astronomical films are mostly glass films with a size of 300mm×300mm. According to the size of astronomical films and the characteristics of film materials, the Shanghai Astronomical Observatory of the Chinese Academy of Sciences has developed astronomical film scanners such as Figure 1 shown.

[0005] like Figure 1 As shown, the main components of the astronomical film scanner include: an imaging camera 1, an imaging lens 2, a light source 3, an astronomical film 4, a film chamber 5, a motion platform 6, a marble platform 7, a scanner base 8, and a scanner control system 9. In this embodiment, the motion platform 6 is a two-dimensional air-floating guide motion platform, and the function of the two-dimensional air-floating guide motion platform is that it can move in the X and Y directions.

[0006] The working principle and process of existing astronomical film scanners are as follows:

[0007] The scanner base 8, marble platform 7, motion platform 6 and film bin 5 are fixed in sequence from bottom to top. The light source 3 is fixed to the bottom of the astronomical film bin 5 (i.e., on the motion platform 6) and does not move. The imaging lens 2 is fixed to the adjustment frame on the marble gantry crossbeam with screws and does not move. The imaging camera 1 is fixed to the imaging lens 2 by screws. Thus, the light source 3, astronomical film 4, imaging lens 2, and imaging camera 1 form an imaging optical path structure of the astronomical film. The scanner control system 9 is connected to the motion platform 6, the light source 3, and the imaging camera 1 in communication to control the motion scanning of the motion platform 6, the start of the light source 3, and the shooting of the imaging camera 1.

[0008] When working, first place the astronomical film 4 in the film bin 5, start the scanner control system 9, first move the platform 6 to the initial position, turn on the light source 3 to illuminate the astronomical film 4, and turn off the indoor lighting. The imaging principle is as follows: the light source 3 illuminates the astronomical film from the bottom, and then the celestial target information on the film is imaged 1:1 on the top imaging camera 1 through the imaging lens 2; because the target surface of the imaging camera 1 is small and the size of the astronomical film 4 is large, the scanner adopts the surface scanning mode: that is, open the scanner control software to start scanning the astronomical film 4 in the surface scanning mode, use the imaging lens 2 and the imaging camera 1 to perform surface scanning and shooting of the astronomical film during scanning, move the astronomical film 4 to the shooting position, and the imaging camera 1 shoots and images, take pictures multiple times, and finally perform image stitching and image data processing on the taken photos, so as to realize the digitalization of the film and save it to restore the image. During the scanning process of the astronomical film 4, the moving platform 6 only drives the astronomical film 4 and the film bin 5 to move. Among them, when working, there are only films and film bins on the moving platform 6.

[0009] When regular precision inspection and calibration are required, other devices may need to be placed on the motion platform 6 to measure the platform error. Since the surface scanning and photography of astronomical films is achieved through the two-dimensional motion platform of the astronomical film scanner, the accuracy of the motion platform of the astronomical film scanner directly affects the accuracy of astronomical film restoration. The precision error comes from the motion error of the film scanner: including: linearity, position positioning accuracy, and repeat positioning accuracy; the attitude error includes: pitch angle, rotation angle, and roll angle, among which the motion attitude of the astronomical film scanner has a certain influence on the scanning and splicing accuracy. Therefore, it is necessary to regularly measure the motion attitude of the astronomical film scanner and perform error compensation to improve the scanning and splicing accuracy.

[0010] For the measurement method of the motion posture of the motion platform of the astronomical film scanner, the laser interferometer of Renishaw or Agilent is often used to measure its posture. Renishaw laser interferometer uses laser interferometer and multiple angle measurement blocks to form a pitch angle measurement system, a rotation angle measurement system and a roll angle test system to measure the motion posture respectively. It is a time-sharing and step-by-step measurement method. Different motion postures need to be measured in combination with different angle measurement modules to build a measurement system. Another method of measuring angles using Agilent's dual-frequency laser interferometer is more complicated. It uses multiple optical components including a beam splitter, multiple interferometers, a plane mirror and an angle mirror to form a more complex motion posture measurement system for measurement.

[0011] Although both measurement methods can measure angular motion, the Agilent dual-frequency laser interferometer requires a more complex measurement system to measure angular motion, which is time-consuming and complex. When Renishaw laser interferometer measures different angular errors, it requires different angular components to measure and obtain the measurement results separately, and cannot obtain the 3D angular motion error at the same time.

[0012] The photoelectric autocollimator can measure the tilt angle. Specifically, the photoelectric autocollimator and a plane reflector together establish an autocollimation measurement system. When the plane reflector is placed on a moving platform and moves, the two-dimensional data of the guide rail motion posture, the pitch angle and the rotation angle, are calculated through the position data of the self-collimated reflected image on the image plane. However, the motion posture of the scanner is a three-dimensional angle, in addition to the pitch angle, the rotation angle, there is also a roll angle, and the roll angle of the plane mirror rotating around the collimated beam will not cause the reflected beam to tilt, so the roll angle cannot be measured. Summary of the invention

[0013] The object of the present invention is to provide a device and method for measuring the motion posture of an astronomical film scanner, so as to solve the problem that the three-dimensional motion posture of the astronomical film scanner cannot be measured simultaneously and realize the simultaneous measurement of the motion posture.

[0014] In order to achieve the above-mentioned object, the present invention provides a device for measuring the motion posture of an astronomical film scanner, comprising an astronomical film scanner to be measured, and a photoelectric autocollimator and a target device arranged opposite to each other, wherein the target device comprises a plane wedge mirror and a three-dimensional adjustment mechanism connected to both the plane wedge mirror and the motion platform of the astronomical film scanner.

[0015] The photoelectric autocollimator is fixed on a frame outside the astronomical film scanner by screws, and the target device is detachably mounted on a moving platform of the astronomical film scanner to be tested.

[0016] The astronomical film scanner to be tested comprises a scanner base, a marble platform, a motion platform and a film bin which are fixed in sequence from bottom to top, wherein the astronomical film is placed in the film bin, and a light source is fixed at the bottom of the astronomical film bin; a marble gantry beam is arranged on the marble platform, an imaging lens is fixed on an adjustment frame on the marble gantry beam by screws, and an imaging camera is fixed on the imaging lens by screws; a scanner control system is communicatively connected with the motion platform, the light source and the imaging camera.

[0017] The target device is fixed on the platform of the film chamber by screws, and is fixed on the moving platform of the astronomical film scanner to be tested through the film chamber.

[0018] The two surfaces of the plane wedge mirror are both planes, the front and rear surfaces are both optically processed, and the two surfaces have a fixed wedge angle.

[0019] The wedge angle of the plane wedge mirror is 30″.

[0020] The front surface of the plane wedge mirror is coated with a semi-transparent and semi-reflective film layer, and the rear surface is coated with a metal reflective film.

[0021] The metal reflective film includes one of an aluminum film, a gold film and a silver film.

[0022] In another aspect, the present invention provides a method for measuring the motion posture of an astronomical film scanner, comprising:

[0023] Step S1: using the astronomical film scanner to be tested to build the above-mentioned measuring device for the motion posture of the astronomical film scanner;

[0024] Step S2: aligning the photoelectric autocollimator with the front surface of the plane wedge mirror, and adjusting the pitch angle and rotation angle of the plane wedge mirror so that the emitted light of the photoelectric autocollimator returns to the detection surface of the photoelectric autocollimator through the front surface of the plane wedge mirror to form a front surface reflection image, and the front surface reflection image coincides with the center of the detection surface of the photoelectric autocollimator;

[0025] Step S3: adjusting the plane wedge mirror to rotate around the optical axis of the light emitted by the photoelectric autocollimator so that the coordinates of the rear surface reflection image on the detection surface of the photoelectric autocollimator are (x, 0);

[0026] Step S4: recording two sets of tilt data of the front surface reflection image and the rear surface reflection image of the plane wedge mirror as initial tilt data;

[0027] Step S5: When the astronomical film scanner scans and moves to a certain position with a three-dimensional motion posture, current tilt data of the front surface reflection image and the rear surface reflection image are measured;

[0028] Step S6: Process the current tilt data and initial tilt data of the obtained front surface reflection image and the rear surface reflection image, decompose the pitch angle and the rotation angle from the current tilt data of the front surface reflection image, and solve the roll angle data excluding the pitch angle and the rotation angle based on the current tilt data, initial tilt data and fixed wedge angle data of the rear surface reflection image.

[0029] The step S1 specifically includes:

[0030] Step S11: installing the plane wedge mirror on the three-dimensional adjustment mechanism to form a target device;

[0031] Step S12: Mount the target device on the motion platform of the astronomical film scanner to be tested.

[0032] The present invention is applied to the measuring device of the motion posture of the astronomical film scanner. Specifically, the photoelectric autocollimator is used to align the target device (including the plane wedge mirror and the three-dimensional adjustment mechanism) on the motion platform of the astronomical film scanner, and the initial reflection images and attitude angle data of the front and rear surfaces of the plane wedge mirror are obtained on the image plane of the photoelectric autocollimator. Then, the new attitude angles and data of the two reflection images are obtained after the platform moves. The three-dimensional motion posture state of the motion platform is evaluated by the inclination of the attitude angles of the two reflection images. The measuring device measures the inclination angles of the reflection images on the two surfaces of the plane wedge mirror through the photoelectric autocollimator, solves the problem that the three-dimensional motion posture of the astronomical film scanner cannot be measured simultaneously, and realizes the simultaneous measurement of the motion posture. In addition, the present invention has the advantages of simple structure and convenient optical path construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a structural system diagram of a typical astronomical film scanner.

[0034] Figure 2 It is a system structure diagram of the measuring device for the motion posture of an astronomical film scanner of the present invention.

[0035] Figure 3 It is a structural diagram of a target device of the present invention applied to a measuring device of the motion posture of an astronomical film scanner.

[0036] Figure 4 This is a definition diagram of the three-dimensional motion attitude angle of an astronomical film scanner.

[0037] Figure 5 This is the reflection image data acquisition interface diagram.

[0038] Figure numerals: 1-imaging camera, 2-imaging lens, 3-light source, 4-astronomical film, 5-film chamber, 6-air-floating two-dimensional motion platform, 7-marble platform, 8-scanner base, 9-scanning control system; 10-astronomical film scanner; 20-photoelectric autocollimator; 30-target device; 31-plane wedge mirror; 32-three-dimensional adjustment mechanism; I1-front surface reflected image, I2-back surface reflected image, I0-photoelectric autocollimator center. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0040] The present invention provides a device for measuring the motion attitude of an astronomical film scanner, which is suitable for measuring the three-dimensional motion attitude angle of the astronomical film scanner. The motion attitude measuring device of the present invention is based on a method for measuring the tilt angle of a photoelectric autocollimator, and realizes real-time motion attitude measurement by using a target device and a photoelectric autocollimator in combination, and uses a wedge mirror to replace a plane mirror as a matching device of the photoelectric autocollimator to realize the measurement of the roll angle in addition to the pitch angle and the rotation angle.

[0041] like Figure 2 and Figure 3 As shown, the device for measuring the motion posture of an astronomical film scanner of the present invention is used to realize the measurement of the three-dimensional motion posture angle of the astronomical film scanner, and includes an astronomical film scanner 10 to be measured, and a photoelectric autocollimator 20 and a target device 30 arranged opposite to each other.

[0042] The astronomical film scanner 10 to be tested is as described above, comprising a scanner base 8, a marble platform 7, a motion platform 6 and a film bin 5 fixed in sequence from bottom to top, an astronomical film 4 is placed in the film bin 5, and a light source 3 is fixed at the bottom of the astronomical film bin 5. A marble gantry crossbeam is provided on the marble platform 7, an imaging lens 2 is fixed to an adjustment frame on the marble gantry crossbeam by screws and does not move, and an imaging camera 1 is fixed to the imaging lens 2 by screws, thereby, the light source 3, the astronomical film 4, the imaging lens 2, and the imaging camera 1 form an imaging optical path structure of the astronomical film. The scanner control system 9 is connected in communication with the motion platform 6, the light source 3 and the imaging camera 1 to control the motion scanning of the motion platform 6, the start of the light source 3 and the shooting of the imaging camera 1.

[0043] The photoelectric autocollimator 20 is fixed to a stable frame outside the astronomical film scanner 10 (especially outside the motion platform of the astronomical film scanner 10) by screws. The target device 30 is detachably mounted on the motion platform 6 of the astronomical film scanner 10 to be tested. Specifically, the target device 30 is fixed to the platform of the film chamber 5 by screws, so as to be fixed to the motion platform 6 of the astronomical film scanner 10 to be tested through the film chamber 5. The target device 30 includes a plane wedge mirror 31 and a three-dimensional adjustment mechanism 32 connected to both the plane wedge mirror 31 and the motion platform of the astronomical film scanner 10.

[0044] like Figure 4 As shown, the three-dimensional adjustment mechanism 32 is used to adjust the three-dimensional motion posture angle of the plane wedge mirror 31, and the three-dimensional motion posture angle includes a pitch angle θ around the x-axis. x , the pitch angle θ around the x-axis x and the roll angle θ around the z-axis z Similarly, the three-dimensional motion attitude angle of the astronomical film scanner also includes the rotation angle θ y , pitch angle θ x and roll angle θ z .

[0045] The photoelectric autocollimator is an instrument that uses the principle of light self-collimation to measure small angles. The present invention uses the photoelectric autocollimator to measure the motion posture of the scanner motion platform. Its working principle is as follows: the target device 30 of the present invention includes a plane wedge mirror 31 and a three-dimensional adjustment mechanism 32. The target device is detachably fixed on the scanner platform. The three-dimensional motion posture angle is decomposed through the information of the reflection image of the target device in the photoelectric autocollimator: the rotation angle θ y , pitch angle θ x and roll angle θ z Specifically, the cross parallel light (i.e., a beam of parallel light with a cross-shaped cross section) emitted from the photoelectric autocollimator is reflected by the front and rear surfaces of the plane wedge mirror 31 of the target device and then returns to the photoelectric autocollimator 20, where it is imaged on the detection camera in the photoelectric autocollimator 20, and the front surface reflection image I1 and the rear surface reflection image I2 are obtained. When the plane wedge mirror is tilted at an inclination angle α, according to the law of reflection of light, the front surface reflection image I1 will produce a displacement d on the camera. The light source of the photoelectric autocollimator 20 and the camera target surface are both located on the focal plane of the objective lens. Based on this, the relationship between the displacement d and the inclination angle α of the plane wedge mirror 31 can be obtained: tanα=d / 2f, where f is the distance between the photoelectric autocollimator 20 and the plane wedge mirror 31. Based on this relationship, the change in the inclination angle of the plane wedge mirror caused by the change in the three-dimensional motion posture angle can be calculated.

[0046] Therefore, by using the photoelectric autocollimator 20 to illuminate the two surfaces of the plane wedge mirror 31, when the moving platform of the astronomical film scanner 10 to be measured has a roll angle posture change, the displacement d between the front surface reflection image I1 and the rear surface reflection image I2 will rotate around the center of the photoelectric autocollimator 20, and the roll angle can be measured at this time.

[0047] In the present invention, both surfaces of the plane wedge mirror 31 are planes, and both the front and rear surfaces are optically processed. Both surfaces have high-precision surface accuracy, and both surfaces have a fixed wedge angle. There is no special regulation on the size of the wedge angle, which is related to the distance d between the photoelectric autocollimator and the plane wedge mirror and the field of view of the photoelectric autocollimator. If the wedge angle is too large, the reflected image will not be within the field of view. In this embodiment, the wedge angle of the plane wedge mirror 31 used is 30". The front surface of the plane wedge mirror 31 is coated with a semi-transparent and semi-reflective film layer (50% of the light is reflected and 50% of the light is transmitted), and the rear surface is coated with a metal reflective film, which includes one of aluminum film, gold film and silver film. Therefore, the reflection data of the two surfaces of the plane wedge mirror 31 can be used to measure the three-dimensional motion posture of the motion platform.

[0048] Based on the above-mentioned device for measuring the motion posture of an astronomical film scanner and its working principle, the present invention also provides a method for measuring the motion posture of an astronomical film scanner, which specifically includes the following steps:

[0049] Step S1: using the astronomical film scanner 10 to be tested to build the above-mentioned measuring device for the motion posture of the astronomical film scanner;

[0050] like Figure 4 As shown, the measuring device for the motion posture of an astronomical film scanner includes an astronomical film scanner 10 to be measured, a photoelectric autocollimator 20 and a target device 30 arranged opposite to each other, a plane wedge mirror 31, and a three-dimensional adjustment mechanism 32 connected to the plane wedge mirror 31 and the motion platform 10 of the astronomical film scanner.

[0051] The step S1 specifically includes:

[0052] Step S11: installing the plane wedge mirror 31 on the three-dimensional adjustment mechanism 32 to form a target device 30;

[0053] Step S12: Mount the target device 30 on the moving platform of the astronomical film scanner 10 to be tested.

[0054] Step S2: Align the photoelectric autocollimator 1 with the front surface of the plane wedge mirror 31, and adjust the pitch angle and rotation angle of the plane wedge mirror 31 so that the light emitted by the photoelectric autocollimator 20 returns to the detection surface of the photoelectric autocollimator 20 through the front surface of the plane wedge mirror 31 to form a front surface reflection image I1, and the front surface reflection image I1 coincides with the center of the detection surface of the photoelectric autocollimator 20;

[0055] like Figure 4 As shown in the figure, the center of the photoelectric autocollimator 20 is I0, and the center of the cross image returned to the detection surface of the photoelectric autocollimator 20 via the front surface of the plane wedge mirror 31 is the front surface reflection image I1, therefore, I0 and I1 in the figure coincide, that is, the front surface reflection image coincides with the center of the photoelectric autocollimator 20. This optical axis center I0 is the inherent and unchanging center in the photoelectric autocollimator.

[0056] At this time, there are two reflected images in the photoelectric autocollimator 1: one is the front surface reflected image I1, and the other is the back surface reflected image I2. At this time, the initial data of the two reflected images are obtained: since the refractive index and wedge angle of the plane wedge mirror are certain, the relative positions of the two reflected images are fixed.

[0057] Step S3: Figure 4 As shown, the plane wedge mirror 31 is adjusted to rotate around the optical axis (i.e., the z-axis) of the light emitted by the photoelectric autocollimator 1, so that the coordinates of the rear surface reflection image I2 on the detection surface of the photoelectric autocollimator 1 are (x, 0), that is, the coordinates of the rear surface reflection image I2 on the y-axis are adjusted to 0;

[0058] Step S4: recording two sets of tilt data of the front surface reflection image I1 and the rear surface reflection image I2 of the plane wedge mirror 31 as initial tilt data;

[0059] Step S5: When the astronomical film scanner scans and moves to a certain position with a three-dimensional motion posture, current tilt data of the front surface reflection image I1 and the rear surface reflection image I2 are measured;

[0060] When the platform moves to a certain position and changes in three-dimensional posture, the coordinate positions of the front surface reflection image I1 and the rear surface reflection image I2 on the detection surface of the photoelectric autocollimator 1 change, and the inclination data of the two reflection images will be obtained.

[0061] Step S6: Process the current tilt data and the initial tilt data of the front surface reflected image I1 and the rear surface reflected image I2, decompose the pitch angle and the rotation angle from the current tilt data of the front surface reflected image I1, and solve the roll angle data excluding the pitch angle and the rotation angle according to the current tilt data, the initial tilt data and the fixed wedge angle data of the rear surface reflected image I2, so as to measure the three-dimensional motion posture of the motion platform.

[0062] The formulas for the pitch angle and the rotation angle are as described above. When the plane wedge mirror 31 tilts at an inclination angle α (the inclination angle α includes the combined angle of the pitch angle and the rotation angle), according to the law of light reflection, the front surface reflection image I1 will produce a displacement d on the camera. The light source of the photoelectric autocollimator 20 and the camera target surface are both located on the focal plane of the objective lens. Based on this, the relationship between the displacement d and the inclination angle α of the plane wedge mirror 31 can be obtained: tanα=d / 2f, where f is the distance between the photoelectric autocollimator 20 and the plane wedge mirror 31. The tilt direction of the plane wedge mirror is obtained according to the direction of the displacement d.

[0063] Since the specific initial position of the rear surface reflected image I2 is (x, 0), when only the roll angle of the plane wedge mirror 31 changes, the position of the rear surface reflected image I2 is (x1, y1), and the roll angle is tanθz=y1 / x1.

[0064] Therefore, the method of the present invention places the plane wedge mirror on the moving platform of the astronomical film scanner and moves with it, obtains the position data of the front surface reflection image and the rear surface reflection image simultaneously through the photoelectric autocollimator software, and determines the inclination angle data of the two reflection images through data processing and analysis, and solves the pitch angle, rotation angle and corresponding roll angle; solves the problem of simultaneous measurement of the three-dimensional attitude angle of the scanner moving platform. The three-dimensional motion attitude angle of the platform, namely the pitch angle, rotation angle and roll angle data, is decomposed by using the inclination data of the inclination deviation amount of the front and rear surface reflection images and the center of the autocollimator, and finally obtains the three-dimensional motion attitude angle of the scanner.

[0065] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A method for measuring the motion posture of an astronomical film scanner, It is characterized in that include: Step S1: using the astronomical film scanner to be tested, constructing a measuring device for the motion posture of the astronomical film scanner; The measuring device for the motion posture of an astronomical film scanner comprises an astronomical film scanner to be measured, and a photoelectric autocollimator and a target device arranged opposite to each other, wherein the target device comprises a plane wedge mirror and a three-dimensional adjustment mechanism connected to the plane wedge mirror and the motion platform of the astronomical film scanner; Step S2: aligning the photoelectric autocollimator with the front surface of the plane wedge mirror, and adjusting the pitch angle and rotation angle of the plane wedge mirror so that the emitted light of the photoelectric autocollimator returns to the detection surface of the photoelectric autocollimator through the front surface of the plane wedge mirror to form a front surface reflection image, and the front surface reflection image coincides with the center of the detection surface of the photoelectric autocollimator; Step S3: adjusting the plane wedge mirror to rotate around the optical axis of the light emitted by the photoelectric autocollimator so that the coordinates of the rear surface reflection image on the detection surface of the photoelectric autocollimator are (x, 0); Step S4: recording two sets of tilt data of the front surface reflection image and the rear surface reflection image of the plane wedge mirror as initial tilt data; Step S5: When the astronomical film scanner scans and moves to a certain position with a three-dimensional motion posture, current tilt data of the front surface reflection image and the rear surface reflection image are measured; Step S6: Process the current tilt data and initial tilt data of the obtained front surface reflection image and the rear surface reflection image, decompose the pitch angle and the rotation angle from the current tilt data of the front surface reflection image, and solve the roll angle data excluding the pitch angle and the rotation angle based on the current tilt data, initial tilt data and fixed wedge angle data of the rear surface reflection image.

2. The method for measuring the motion posture of an astronomical film scanner according to claim 1, It is characterized in that The step S1 specifically includes: Step S11: installing the plane wedge mirror on the three-dimensional adjustment mechanism to form a target device; Step S12: Mount the target device on the motion platform of the astronomical film scanner to be tested.

3. The method for measuring the motion posture of an astronomical film scanner according to claim 1, It is characterized in that The photoelectric autocollimator is fixed on a frame outside the astronomical film scanner by screws, and the target device is detachably mounted on a moving platform of the astronomical film scanner to be tested.

4. The method for measuring the motion posture of an astronomical film scanner according to claim 3, It is characterized in that The astronomical film scanner to be tested includes a scanner base, a marble platform, a motion platform and a film bin fixed in sequence from bottom to top, wherein the astronomical film is placed in the film bin, and the light source is fixed at the bottom of the astronomical film bin; a marble gantry beam is provided on the marble platform, an imaging lens is fixed to an adjustment frame on the marble gantry beam with screws, and an imaging camera is fixed to the imaging lens with screws; the motion platform, the light source and the imaging camera are communicatively connected with a scanner control system.

5. The method for measuring the motion posture of an astronomical film scanner according to claim 4, It is characterized in that The target device is fixed on the platform of the film chamber by screws, and is fixed on the moving platform of the astronomical film scanner to be tested through the film chamber.

6. The method for measuring the motion posture of an astronomical film scanner according to claim 1, It is characterized in that Both surfaces of the plane wedge mirror are planes, the front surface and the rear surface are optically processed, and there is a fixed wedge angle between the two surfaces.

7. The method for measuring the motion posture of an astronomical film scanner according to claim 6, It is characterized in that The wedge angle of the plane wedge mirror is 30″.

8. The method for measuring the motion posture of an astronomical film scanner according to claim 6, It is characterized in that The front surface of the plane wedge mirror is coated with a semi-transparent and semi-reflective film layer, and the rear surface is coated with a metal reflective film.

9. The method for measuring the motion posture of an astronomical film scanner according to claim 8, It is characterized in that The metal reflective film includes one of an aluminum film, a gold film and a silver film.

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