Optical system image tilt detection system and method

Abstract

The invention relates to the technical field of photoelectric system detection, and in particular to an optical system object image tilt detection system and method; the system comprises a collimator, a graticule assembly, a guide rail, a reflector assembly, a detection tool assembly, an optical system to be measured, an image inclinometer, a horizontal adjustment table and a level meter; the collimator is installed on the guide rail and keeps a horizontal state, and the graticule assembly is located at an infinite position at the rear end of the collimator; the reflector assembly is installed in front of the collimator and is used to reflect the parallel light emitted by the collimator downward by 90 degrees; the horizontal adjustment table is directly below the reflector assembly and is used to place and fix the optical system to be measured, and the horizontal adjustment table is used to adjust the horizontal direction; the invention solves the problem that the image tilt of the state of optical system components cannot be detected, avoids unqualified components from flowing into the assembly of the whole machine, saves the time and cost of the whole machine rework, greatly improves the production efficiency, and is worthy of being promoted and used in similar products.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic system detection, and in particular to an optical system object image tilt detection system and method. Background Art

[0002] The commander's periscope is required to observe and scan 360° in azimuth. During azimuth rotation scanning, since the optical system drives the head pitch component (upper reflector) to rotate through the middle azimuth component to achieve 360° scene observation, the observed image will rotate with the rotation of the head pitch component, and the image rotation will produce image rotation, such as Figure 2 As shown; the rotation of the visual sight image is eliminated by rotating the Behan prism, ensuring that the image seen by the human eye from the eyepiece is always upright; the observed imaging is consistent with the actual target and has a high precision requirement. At present, the commonly used optical derotation methods for optical systems in optoelectronic instruments are Dove prism and Behan prism. In the present invention, we prefer the optical derotation scheme of the Behan prism derotation mechanism.

[0003] Method for detecting the image tilt of the commander's panoramic sight: Generally, the image tilt detection of the commander's panoramic sight is established in the state of the whole machine. A plumb line (the plumb line is placed in water to increase damping) is hung about 20m in front of the product. Place the product on the bracket and adjust the level with the flange base as the reference. Place the image inclinometer behind the eyepiece and adjust the level. Measure the inclination angle between the vertical division line and the plumb line in the image inclinometer, which is the image tilt. Turn the product (or bracket) clockwise or counterclockwise so that the eyepiece and the front are about 0°, 90°, 180°, and 270°. Repeat the above leveling and measurement steps. The measured image tilt should also meet the requirements.

[0004] The present invention relates to a system and method for detecting the tilt of an optical system when a central azimuth component and a head pitch component are not assembled. The present invention solves the problem that the tilt of optical system components cannot be detected, avoids unqualified components from flowing into the assembly of the whole machine, saves the time and cost of reworking the whole machine, greatly improves production efficiency, and saves time and cost. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides an optical system image tilt detection system and method, which uses an encoder to accurately measure the rotation angle of the anti-image rotation system, and cooperates with an inclinometer to realize the backlash detection of the anti-image rotation transmission mechanism of the optical system in the component state (i.e., image tilt detection), thereby reducing the influence of the components on the image tilt index of the entire machine.

[0006] The present invention is achieved through the following technical solutions:

[0007] An optical system image tilt detection system; comprising a collimator, a graticule assembly, a guide rail, a reflector assembly, a detection tool assembly, a measured optical system, an image inclinometer, a level adjustment table and a level;

[0008] The collimator is installed on the guide rail and kept in a horizontal state, and the reticle assembly is located at an infinite position at the rear end of the collimator;

[0009] The reflector assembly is installed in front of the collimator and is used to reflect the parallel light emitted by the collimator downward by 90°;

[0010] The horizontal adjustment platform is directly below the reflector assembly and is used to place and fix the optical system to be measured, and the horizontal adjustment platform is used to perform horizontal adjustment;

[0011] The level is used to detect whether the optical system under test is in a horizontal state; the detection fixture assembly is located on the upper end surface of the optical system under test;

[0012] The image inclinometer is placed in front of the eyepiece of the optical system to be measured and adjusted to be horizontal.

[0013] Preferably, the graticule assembly includes a graticule frame, a graticule and a cross-line with an arrow; a cross-line with an arrow is engraved on the graticule, and the angle of the cross-line is set to 90°. To facilitate identification of the direction, an arrow is added to the top of a scale line, and the arrow is directed upward and parallel to the direction of the plumb line.

[0014] Preferably, the detection tooling assembly includes an encoder, a display box, a torsion spring, a connecting shaft, a handwheel, a base, a bracket and a coaxial device; the detection tooling assembly is connected to the optical system to be measured through the base, the bracket is provided on the base, a connecting shaft is vertically rotatably plugged on the bracket, the encoder, the handwheel and the coaxial device are sequentially provided on the connecting shaft from top to bottom, the connecting shaft also includes the torsion spring sleeved thereon, so that the encoder and the connecting shaft remain vertical, and the encoder is electrically connected to the display box.

[0015] Preferably, the optical system to be measured includes an anti-image rotation transmission mechanism, which mainly includes a Behan prism assembly, a large bevel gear, a small bevel gear, a lower universal joint fork mechanism, a connecting rod mechanism and an upper universal joint fork mechanism; the lower end of the coaxial device is connected to the connecting rod mechanism through the upper universal joint fork mechanism, and the lower end of the connecting rod mechanism is connected to the small bevel gear through the lower universal joint fork mechanism, the large bevel gear and the small bevel gear are respectively rotatably arranged in the optical system to be measured, and the large bevel gear and the small bevel gear are meshed and transmitted to drive the Behan prism assembly to rotate.

[0016] The present invention also provides the following technical solution: a method for using an optical system object tilt detection system, using the above-mentioned optical system object tilt detection system, comprising the following steps:

[0017] Use encoder to accurately measure the rotation angle of the anti-rotation system, and cooperate with image inclinometer to realize the backlash detection of the anti-rotation transmission mechanism in the optical system under the component state, that is, image tilt detection;

[0018] The backlash of the image-eliminating transmission mechanism includes the accumulated errors caused by the transmission backlash of the Behan prism gear, the connection backlash of the universal joint fork and the connecting rod mechanism, the transmission backlash of the coaxial device, and the like.

[0019] Preferably, the method specifically comprises the following steps:

[0020] Place the optical system to be tested on a level adjustment table and fix it, place the inspection fixture assembly on the upper end surface of the optical system to be tested, connect it and fix it with screws; place a level on the inspection fixture assembly, and ensure that the level is in a horizontal state by adjusting the level adjustment table;

[0021] Place the image inclinometer in front of the eyepiece of the optical system to be measured and adjust it to a horizontal level. Rotate the Pehan prism assembly in the optical system to be measured. Observe that the vertical graticule in the image inclinometer is parallel to the cross graticule with arrow in the collimator, and make the arrow point upward.

[0022] Turn the hand wheel to make the encoder signal output display value on the display screen stay at 0, tighten the screws on the coaxial device, and connect the detection fixture assembly with the optical system to be tested;

[0023] Turn the hand wheel clockwise to make the encoder display value 0, read the inclination of the cross-reticle through the image inclinometer and record the data, turn the hand wheel counterclockwise to make the encoder display value 0, read the inclination of the cross-reticle through the image inclinometer and record the data, the difference between the two data is the zero-position backlash, according to the working characteristics of the Behan prism assembly in the optical system under test, the Behan prism assembly completes a cycle of movement;

[0024] Therefore, the above method is used to read the encoder at seven positions of 225°, 450°, 675°, 900°, 1125°, 1350°, and 1535°, and a total of 14 valid data of the image inclinometer are obtained. At this time, a total of 16 data of eight detection points are counted, and none of them can exceed the system requirements for the backlash and the object image tilt index. In this way, one cycle completes the detection of the object image tilt index of the measured system.

[0025] The beneficial effects of the present invention are:

[0026] The present invention solves the problem that image tilt of the optical system components cannot be detected, that is, it effectively solves the problem that the optical system cannot perform image tilt detection when the central azimuth component and the head pitch component are not assembled, thereby avoiding unqualified components from flowing into the assembly of the whole machine, saving the time and cost of reworking the whole machine, and greatly improving production efficiency. It is worthy of promotion and use in similar products. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of the structure of the optical system image tilt detection system of the present invention;

[0029] Figure 2 It is a schematic diagram of the image rotation of the present invention;

[0030] Figure 3 Schematic diagram of the working of the Bihan prism of the present invention;

[0031] Figure 4 It is a schematic diagram of the structure of the graticule assembly of the present invention;

[0032] Figure 5 It is a schematic diagram of the structure of the image-rotation-eliminating transmission mechanism of the present invention;

[0033] Figure 6 This is a schematic diagram of the transmission direction structure of the large and small bevel gears of the present invention;

[0034] Figure 7 It is a schematic diagram of the parameter structure of the large and small bevel gears of the present invention;

[0035] Figure 8 It is a schematic diagram of the structure of the detection tooling assembly of the present invention.

[0036] In the figure: 1-collimator, 2-graticule assembly, 3-guide rail, 4-reflector assembly, 5-detection fixture assembly, 6-measured optical system, 7-image inclinometer, 8-horizontal adjustment table, 9-level, 10-graticule frame, 11-graticule, 12-cross graticule with arrow, 13-base, 14-encoder, 15-torsion spring, 16-handwheel, 17-bracket, 18-connecting shaft, 19-coaxial device, 20-display box, 21-Behan prism assembly, 22-large bevel gear, 23-small bevel gear, 24-lower universal fork mechanism, 25-connecting rod mechanism, 26-upper universal fork mechanism. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Embodiment 1:

[0039] See also Figures 1 to 8 As shown, this embodiment specifically discloses a technical solution of an optical system object image tilt detection system, including a collimator 1, a graticule assembly 2, a guide rail 3, a reflector assembly 4, a detection fixture assembly 5, a measured optical system 6, an image inclinometer 7, a horizontal adjustment table 8 and a level 9;

[0040] The collimator 1 is installed on the guide rail 3 and kept in a horizontal state, and the reticle assembly 2 is located at an infinite position at the rear end of the collimator 1;

[0041] The reflector assembly 4 is installed in front of the collimator 1, and is used to reflect the parallel light emitted by the collimator 1 downward by 90 degrees;

[0042] The horizontal adjustment platform 8 is located directly below the reflector assembly 4 and is used to place and fix the optical system 6 to be measured. The horizontal adjustment platform 8 is also used to adjust the horizontal direction.

[0043] The level 9 is used to detect whether the optical system 6 to be measured is in a horizontal state; the detection fixture assembly 5 is located on the upper end surface of the optical system 6 to be measured;

[0044] The image inclinometer 7 is placed in front of the eyepiece of the optical system 6 to be measured and adjusted to be horizontal.

[0045] Specifically, the graticule assembly 2 includes a graticule frame 10, a graticule 11 and a cross-line 12 with an arrow; a cross-line 12 with an arrow is engraved on the graticule 11, and the angle of the cross-line is set to 90°. To facilitate the identification of the direction, an arrow is added to the top of a scale line, and the arrow direction is upward and parallel to the plumb line direction.

[0046] Specifically, the detection tooling assembly 5 includes an encoder 14, a display box 20, a torsion spring 15, a connecting shaft 18, a handwheel 16, a base 13, a bracket 17 and a coaxial device 19; the detection tooling assembly 5 is connected to the optical system 6 to be measured through the base 13, and a bracket 17 is provided on the base 13. A connecting shaft 18 is vertically rotatably plugged on the bracket 17, and the connecting shaft 18 is provided with an encoder 14, a handwheel 16 and a coaxial device 19 from top to bottom. The connecting shaft 18 also includes a sleeved torsion spring 15 to keep the encoder 14 and the connecting shaft 18 vertical, and the encoder 14 is electrically connected to the display box 20.

[0047] When the above-mentioned detection fixture assembly 5 is used, the encoder 14 is a rotary absolute encoder 14 with an angle measurement accuracy of 0.03°; the display box 20 is a carrier for outputting the angle value of the encoder 14. The above-mentioned encoder 14 is elastically connected to the bracket 17 due to its own spring leaf at the bottom. The measuring shaft at the bottom of the encoder 14 is connected to the upper end of the above-mentioned connecting shaft 18. The upper end of the torsion spring 15 is connected to the bottom of the encoder 14, and the lower end is connected to the bracket 17. Therefore, the torsion spring 15 uses a vertical upward force to keep the encoder 14 and the shaft perpendicular to each other, thereby reducing the measurement caused by the angle between the two. Error; connecting shaft 18 is a coaxial device used to connect encoder 14, handwheel 16, torsion spring 15 and coaxial device 19 in series; handwheel 16 is rotated by hand to drive the image rotation transmission mechanism of the optical system 6 under test and the synchronous motion mechanism of encoder 14; coaxial device 19 is a connecting device matched with the product under test; bracket 17 is a limit device for encoder 14 and handwheel 16; base 13 is a connecting device for the optical system 6 under test and the measuring tooling assembly; inclinometer is a measuring device with horizontal positioning accuracy: 30" reading handwheel 16 grid value, 30" image tilt measurement range and ±3.

[0048] Specifically, the optical system 6 to be measured includes an image rotation elimination transmission mechanism, which mainly includes a Bihan prism assembly 21, a large bevel gear 22, a small bevel gear 23, a lower universal joint fork mechanism 24, a connecting rod mechanism 25 and an upper universal joint fork mechanism 26; the lower end of the coaxial device 19 is connected to the connecting rod mechanism 25 through the upper universal joint fork mechanism 26, and the lower end of the connecting rod mechanism 25 is connected to the small bevel gear 23 through the lower universal joint fork mechanism 24, the large bevel gear 22 and the small bevel gear 23 are respectively rotatably arranged in the optical system 6 to be measured, and the large bevel gear 22 and the small bevel gear 23 are meshed and transmitted to drive the Bihan prism assembly 21 to rotate.

[0049] When this embodiment is used, the following contents are also specifically disclosed:

[0050] Regarding the setting of the angle of the reticle 11, according to technical requirements, the commander's periscope mirror needs to be tested at four angle detection points: 0°, 90°, 180°, and 270°. Therefore, the angle of the reticle is set to a cross-shaped 90° cross, such as Figure 4 As shown, an arrow can be added to the top of a scale line to facilitate identification of direction.

[0051] The setting of the detection range is determined by the characteristics of the Behan prism; the Behan prism is composed of two bisected prisms, and the air gap between them is approximately 0.05mm. Figure 3 As shown. One of its characteristics is that when it rotates around the optical axis at an angle of α, the exit surface and the incident surface image rotate in the same direction at an angle of 2α. Using this principle, in practical applications, when the incident light rotates and scans at an angle of ω in the azimuth direction, the mechanical transmission chain drives the Behan prism to rotate in the opposite direction at an angle of ω / 2 around the optical axis, so that the image of the eyepiece does not rotate during observation, which plays the role of eliminating image rotation. Therefore, to achieve one rotation of the Behan prism, the horizontal direction must be rotated in the opposite direction twice. According to technical requirements, the commander's periscope needs to be tested at four specific angle detection points of 0°, 90°, 180°, and 270°. Therefore, it is necessary to detect the specific angles twice, a total of eight detection points, to cover one rotation cycle of the Behan prism.

[0052] Regarding the angle calculation of the encoder 14 as the measuring point, first, the anti-rotation mechanism transmission system is composed of a group of large and small bevel gears 23, an upper universal joint fork mechanism 26, a lower universal joint fork mechanism 24, a connecting rod mechanism 25, and a coaxial device 19 mechanism, such as Figure 5 As shown, the detection fixture assembly 5 and the small bevel gear 23 are connected one by one through the upper and lower universal joint fork mechanism 24, the connecting rod mechanism 25, the upper universal joint fork mechanism 26, and the coaxial device 19 mechanism, so it is a one-to-one synchronous rotation. The gear set consists of a large bevel gear 22 and a small bevel gear 23, as shown in FIG. Figure 6 As shown, the transmission ratio is the ratio of the angular velocity or speed of the starting driving wheel and the end driven wheel in the mechanical transmission system. The transmission ratio (i) = the ratio of the driving wheel speed n1 to the driven wheel speed n2 = the inverse ratio of the gear pitch circle diameter = the ratio of the driven gear teeth Z2 to the driving gear teeth Z1. That is: i = z2 / z1 = n1 / n2;

[0053] In the preferred solution, the driving wheel is a small bevel gear 23 with 34 teeth; the driven wheel is a large bevel gear 22 with 170 teeth; Figure 7 As shown;

[0054] From z2=170, z1=34, i=z2 / z1=170 / 34=5;

[0055] Therefore, the encoder 14 needs to rotate 5 circles to drive the Behan prism to rotate one circle. Combined with the characteristics of the Behan prism, there are a total of 8 detection points. Therefore, the encoder 14 increases one detection point for every 0.625 circle 225°; the specific detection point angles in the angle value output display box 20 are 0°, 225°, 450°, 675°, 900°, 1125°, 1350° and 1535°.

[0056] The present invention also provides the following technical solution: a method for using an optical system object tilt detection system, using the above-mentioned optical system object tilt detection system, comprising the following steps:

[0057] The encoder 14 is used to accurately measure the rotation angle of the image derotation system, and the image inclinometer 7 is used to realize the backlash detection of the image derotation transmission mechanism in the component state of the optical system, that is, the image tilt detection;

[0058] The backlash of the image-eliminating transmission mechanism includes the accumulated errors caused by the transmission backlash of the Behan prism gear, the connection backlash of the universal joint and the connecting rod mechanism 25, and the transmission backlash of the coaxial device 19.

[0059] Specifically, the steps include:

[0060] According to Figure 1 , 4 As shown in , 5 and 8, the optical system 6 to be measured is placed on the horizontal adjustment table 8 and fixed, and the detection fixture assembly 5 is placed on the upper end surface of the optical system 6 to be measured and connected and fixed with screws; a level 9 is placed on the detection fixture assembly 5, and the level 9 is ensured to be in a horizontal state by adjusting the horizontal adjustment table 8;

[0061] Place the image inclinometer 7 in front of the eyepiece of the optical system 6 to be measured and adjust it to a horizontal level. Rotate the Behan prism assembly 21 in the optical system 6 to be measured. Observe that the vertical graticule in the image inclinometer 7 is parallel to the cross graticule with an arrow in the collimator 1, and make the arrow point upward.

[0062] Turn the hand wheel 16 to make the signal output of the encoder 14 displayed on the display box 20 remain at 0, and tighten the screws on the coaxial device 19 to connect the detection fixture assembly 5 with the optical system 6 to be tested;

[0063] The hand wheel 16 is rotated clockwise to make the encoder 14 display a value of 0, and the tilt of the cross-reticle is read through the image inclinometer 7 and the data is recorded. The hand wheel 16 is rotated counterclockwise to make the encoder 14 display a value of 0, and the tilt of the cross-reticle is read through the image inclinometer 7 and the data is recorded. The difference between the two data is the zero-position backlash. According to the working characteristics of the Behan prism assembly 21 in the optical system 6 to be measured, the Behan prism assembly 21 completes a cycle of movement.

[0064] Therefore, the above method is used to read the encoder 14 at seven positions of 225°, 450°, 675°, 900°, 1125°, 1350°, and 1535°, respectively, and a total of 14 valid data of the image inclinometer 7 are obtained. At this time, a total of 16 data of eight detection points are counted, and none of them can exceed the system requirements for the backlash and the object image tilt index. In this way, one cycle completes the detection of the object image tilt index of the measured system.

[0065] The technical problem to be solved by the present invention is to use an encoder to accurately measure the rotation angle of the anti-image rotation system, and cooperate with the inclinometer to realize the backlash detection of the anti-image rotation transmission mechanism (i.e. image tilt detection) of the optical system in the component state; and reduce the influence of the components on the object tilt index of the whole machine.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical system object tilt detection system, characterized in that: It comprises a collimator (1), a graticule assembly (2), a guide rail (3), a reflector assembly (4), a detection fixture assembly (5), a measured optical system (6), an image inclinometer (7), a horizontal adjustment platform (8) and a level (9); The collimator (1) is mounted on the guide rail (3) and maintained in a horizontal state, and the reticle assembly (2) is located at an infinite position at the rear end of the collimator (1); The reflector assembly (4) is installed in front of the collimator (1) and is used to reflect the parallel light emitted by the collimator (1) downward by 90°; The horizontal adjustment platform (8) is located directly below the reflector assembly (4) and is used to place and fix the optical system (6) to be measured. The horizontal adjustment platform (8) is also used to perform horizontal adjustment. The level (9) is used to detect whether the optical system (6) to be measured is in a horizontal state; the detection tooling assembly (5) is located on the upper end surface of the optical system (6) to be measured; The image inclinometer (7) is placed in front of the eyepiece of the optical system (6) to be measured and adjusted to be horizontal; The reticle assembly (2) comprises a reticle frame (10), a reticle (11) and a cross-reticle with an arrow (12); the reticle (11) is engraved with a cross-reticle with an arrow (12), and the angle of the cross-reticle is set to 90°; The detection tooling assembly (5) comprises an encoder (14), a display box (20), a torsion spring (15), a connecting shaft (18), a hand wheel (16), a base (13), a bracket (17) and a coaxial device (19); the detection tooling assembly (5) is connected to the optical system (6) to be measured via the base (13); the bracket (17) is provided on the base (13); a connecting shaft (18) is vertically rotatably plugged on the bracket (17); the encoder (14), the hand wheel (16) and the coaxial device (19) are sequentially provided on the connecting shaft (18) from top to bottom; the connecting shaft (18) also comprises the torsion spring (15) sleeved thereon, so that the encoder (14) and the connecting shaft (18) are kept vertical, and the encoder (14) is electrically connected to the display box (20); The optical system (6) to be measured comprises an image derotation transmission mechanism, which comprises a Behan prism assembly (21), a large bevel gear (22), a small bevel gear (23), a lower universal joint fork mechanism (24), a connecting rod mechanism (25) and an upper universal joint fork mechanism (26); the lower end of the coaxial device (19) is connected to the connecting rod mechanism (25) through the upper universal joint fork mechanism (26), and the lower end of the connecting rod mechanism (25) is connected to the small bevel gear (23) through the lower universal joint fork mechanism (24); the large bevel gear (22) and the small bevel gear (23) are respectively rotatably arranged in the optical system (6) to be measured, and the large bevel gear (22) and the small bevel gear (23) are meshed and driven to drive the Behan prism assembly (21) to rotate.

2. A method for using an optical system object tilt detection system, using the optical system object tilt detection system according to claim 1, characterized in that: The method comprises the following steps: using an encoder (14) to accurately measure the rotation angle of the anti-image rotation transmission mechanism, and cooperating with an image inclinometer (7) to implement backlash detection of the anti-image rotation transmission mechanism in a component state of the optical system, namely, image inclination detection; The backlash of the image-eliminating transmission mechanism includes the accumulated error generated by the backlash of the Behan prism gear transmission, the backlash of the universal joint fork and the connecting rod mechanism (25), and the backlash of the coaxial device (19).

3. The method for using the optical system object tilt detection system according to claim 2, characterized in that: The specific steps include: The optical system (6) to be measured is placed on a level adjustment table (8) and fixed, and the detection fixture assembly (5) is placed on the upper end surface of the optical system (6) to be measured, connected and fixed with screws; a level meter (9) is placed on the detection fixture assembly (5), and the level meter (9) is ensured to be in a horizontal state by adjusting the level adjustment table (8); The image inclinometer (7) is placed in front of the eyepiece of the optical system (6) to be measured and adjusted to be horizontal. By rotating the Pechan prism assembly (21) in the optical system (6) to be measured, the vertical graticule in the image inclinometer (7) is parallel to the cross graticule with an arrow in the collimator (1), and the arrow is directed upward. The hand wheel (16) is rotated to make the signal output of the encoder (14) displayed on the display box (20) remain at 0, and the screws on the coaxial device (19) are tightened to connect the detection fixture assembly (5) and the optical system (6) to be measured as a whole; The hand wheel (16) is rotated clockwise to make the encoder (14) display a value of 0, and the inclination of the cross-reticle is read through the image inclinometer (7) and the data is recorded; the hand wheel (16) is rotated counterclockwise to make the encoder (14) display a value of 0, and the inclination of the cross-reticle is read through the image inclinometer (7) and the data is recorded, and the difference between the two data is the zero-position backlash amount. According to the working characteristics of the Behan prism assembly (21) in the optical system (6) to be measured, the Behan prism assembly (21) completes a cycle of movement; Therefore, by using the above method, when the encoder (14) is read at seven positions of 225°, 450°, 675°, 900°, 1125°, 1350° and 1535°, a total of 14 valid data are obtained from the image inclinometer (7). At this time, a total of 16 data are counted from eight detection points, none of which can exceed the system requirements for the backlash amount and the object image inclination index. Thus, one cycle completes the detection of the object image inclination index of the system under test.

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