System and method for aligning and adjusting optical axis and visual axis of continuous zoom television camera

Abstract

The invention relates to the technical field of optical adjustment of television cameras, in particular to an optical axis and visual axis alignment adjustment method for a continuous zoom television camera, and aims to enable the position of an observation target in a view field to be stable and immovable during long and short focus conversion of the continuous zoom television camera and improve the optical axis and visual axis alignment adjustment accuracy on the premise that the imaging quality is not affected. An optical axis and visual axis of a continuous zoom television camera constructed based on an optical bench, a precise four-dimensional rotary table, a cross curve target, a display control board, a test computer, test software and a television monitor are adopted to be aligned with an adjustment platform in the whole course, and an image of the cross curve target plate and an electric cross curve of a low-light camera assembly are adjusted to coincide; according to the method, alignment and calibration of the optical axis and the visual axis of the continuous zoom television camera are divided into three stages, the three stages are progressive in sequence, blind trial is avoided, operability is improved, and the alignment precision can reach the pixel level.

Description

Technical Field

[0001] The invention belongs to the technical field of optical adjustment of television cameras, and in particular relates to an optical axis and visual axis alignment adjustment system and method for a continuous zoom television camera. Background Art

[0002] Continuous zoom TV cameras can continuously change the focal length. When the focal length is short, the field of view is large and the observation range is also large, which is conducive to finding and capturing targets; when the focal length is long, the field of view is small, which is suitable for observing the details of the target or distant targets. Therefore, continuous zoom TV cameras are widely used in aviation, aerospace, weapons and other fields for measuring, tracking and positioning distant targets.

[0003] The rotational symmetry axis of the optical lens is the optical axis, and the straight line passing through the center point of the detector and perpendicular to the photosensitive surface of the detector is the visual axis. The center position of the field of view of a continuous zoom TV camera needs to remain unchanged during the zoom process and before and after zooming to ensure stable observation and not lose the target. Therefore, the visual axis and optical axis of the continuous zoom TV camera need to maintain alignment accuracy at different focal lengths.

[0004] In the prior art, the alignment and adjustment of the optical axis and the visual axis of a continuous zoom television camera requires repeated attempts by operators with installation and adjustment experience, which is time-consuming and has poor operability. Based on this, a system and method for aligning and adjusting the optical axis and the visual axis of a continuous zoom television camera are proposed. Summary of the invention

[0005] The present invention mainly provides a system and method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera, so as to solve the technical problem that the alignment and adjustment of the optical axis and visual axis of the existing continuous zoom television camera proposed in the above background technology requires repeated attempts by operators with installation and adjustment experience, which is time-consuming and has poor operability.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: The invention discloses an optical axis and visual axis alignment and adjustment system for a continuous zoom television camera, the system comprises a zoom television camera, an optical bench, a four-dimensional turntable, a display control board, a test computer and a television monitor, wherein the optical bench comprises a collimator, a crosshair target plate, a light source and a measuring microscope, the light source of the optical bench illuminates the crosshair target plate, the collimator collimates the imaging light transmitted by the crosshair target plate to form an image projected to infinity, the image is regarded as an object by the continuous zoom television camera, and converges into an image of the crosshair target plate on its focal plane.

[0007] In a preferred embodiment of the present invention, the connected zoom television camera is composed of a low-light-level continuous zoom lens, a low-light-level camera component, a motor component, and a video acquisition display and motor control component.

[0008] In a preferred embodiment of the present invention, the continuous zoom television camera is fixed to the precision four-dimensional turntable through a flange, and the precision four-dimensional turntable is fixed to the guide rail of the optical bench through a dovetail groove structure and adjusted to be optically coaxial with the parallel light tube of the optical bench and the measuring microscope.

[0009] In a preferred embodiment of the present invention, the camera assembly of the continuous zoom television camera, the video acquisition display and motor control assembly, the display control board, the television monitor and the test computer are electrically connected.

[0010] The present invention also provides a method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera, which is characterized by comprising the following steps: S1, constructing the above-mentioned continuous zoom TV camera optical axis and visual axis alignment adjustment system; S2, alignment and adjustment of the optical axis and visual axis of the continuous zoom television camera throughout the zoom process; The specific steps of S2 include S21, adjusting so that the optical axis of the collimator coincides with the optical axis of the zoom lens; S22, determining the focus zero position and the image plane position of the low-light level continuous zoom lens; S23. Align and adjust the optical axis and visual axis of the continuous zoom television camera to ensure that the crosshair image of the reticle and the electric crosshair of the continuous zoom television camera remain consistent throughout the zooming process.

[0011] In a preferred embodiment of the present invention, the specific steps of S21 include S211. First, place the low-light level continuous zoom lens between the collimator and the measuring microscope, place a crosshair graticule target plate on the focal plane of the collimator, and adjust the relative position and angle of the precision four-dimensional turntable and the measuring microscope until the clarity of the crosshair image of the graticule formed by the telephoto end of the continuous zoom lens observed through the measuring microscope meets the preset requirements; S212, adjusting the zoom lens to the short focal end through the zoom cam, observing the crosshair image of the reticle through the measuring microscope, and marking its position in the image plane. If the image clarity is too low, adjusting it through the focusing assembly to achieve clear recognition; then adjusting the zoom lens to the long focal end through the zoom cam again, and adjusting the crosshair image of the reticle at the long focal end to the position of the crosshair image marked at the short focal end by adjusting the precision four-dimensional turntable; S213, repeatedly adjusting in this way until the positions of the cross-line images of the graticule formed by the long focal end and the short focal end of the continuous zoom lens remain coincident, and at this time, the optical axis of the collimator coincides with the optical axis of the continuous zoom lens.

[0012] In a preferred embodiment of the present invention, the specific steps of S22 include S221. First, adjust the continuous zoom lens to the telephoto end through the zoom cam, and adjust the measuring microscope until the clarity of the cross-line image of the reticle meets the preset requirements; S222, then adjust the zoom lens to the short focal end through the zoom cam, and observe the crosshair image of the reticle with the measuring microscope. If the image clarity does not meet the requirement, use the focusing group to adjust the focus until the image clarity meets the requirement; then adjust the zoom lens to the long focal end again, and observe the crosshair image of the reticle with the measuring microscope. If the clarity does not meet the requirement, repeat the above process until the requirement is met. S223. Finally, fix the focus group and mark the position of the focus group, which is the focus zero position. At this time, the focal plane position of the measuring microscope is the image plane position of the continuous zoom lens.

[0013] In a preferred embodiment of the present invention, the specific steps of S23 include S231, firstly, the flange structure is used in combination with a gasket to fine-tune the camera assembly to ensure that the photosensitive surface of the camera assembly coincides with the image surface of the continuous zoom lens; S232, then run the test software on the test computer to issue a command, and pass it to the display control board, which controls the camera component to display the electric crosshairs on the TV monitor through the video acquisition display and motor control component. At the same time, the crosshairs of the reticle at the focal plane of the collimator are imaged on the camera component through the continuous zoom TV camera lens, and the TV monitor is driven to display through the video acquisition and motor control component; S233. In view of the difference between the positions of the reticle crosshairs and the electric crosshairs, the precise four-dimensional turntable and the camera assembly are adjusted in coordination to achieve that the reticle crosshairs and the electric crosshairs of the continuous zoom television camera are always consistent throughout the zoom range.

[0014] In a preferred embodiment of the present invention, in order to eliminate the difference between the position of the reticle crosshair image and the electric crosshair in step S233, it is necessary to align the optical axis and the visual axis of the continuous zoom television camera, and the specific steps include: First, the zoom TV camera is adjusted to the short focal length using the zoom cam, and then the radial position of the camera assembly is adjusted so that the reticle crosshair image displayed on the TV monitor coincides with the electric crosshair; Then use the zoom cam to adjust the continuous zoom TV camera to the telephoto end, observe the overlap of the electric crosshairs and the reticle crosshairs displayed on the TV monitor, if there is a position difference, adjust the precision four-dimensional turntable to make the electric crosshairs and the reticle crosshairs displayed on the TV monitor overlap, until the continuous zoom TV camera is at the telephoto end and the short focal end, the electric crosshairs and the reticle crosshairs displayed on the TV monitor always overlap.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention divides the alignment and adjustment of the optical axis and the visual axis of a continuous zoom television camera into three stages, which are progressive in sequence, thereby avoiding blind trials and improving operability, and the alignment accuracy can reach pixel level.

[0016] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram of the alignment and adjustment system of the optical axis and the visual axis of the continuous zoom television camera of the present invention; Figure 2 It is a structural diagram of the continuous zoom television camera of the present invention.

[0018] Among them, 1. low-light level continuous zoom lens; 2. low-light level camera assembly; 3. motor assembly; 4. video acquisition display and motor control assembly; 5. continuous zoom TV camera; 6. optical stand; 6-1. collimator; 6-2. crosshair target; 6-3. light source; 6-4. measuring microscope; 7-precision four-dimensional turntable; 8-display and control board; 9-test computer; 10-TV monitor. DETAILED DESCRIPTION

[0019] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0020] Reference Figure 1-2 The present embodiment provides a method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera. In order to make the position of the observed target in the field of view stable and immovable when the continuous zoom television camera changes from long to short focal length, without affecting the imaging quality, a continuous zoom television camera optical axis and visual axis full alignment and adjustment platform based on an optical stand 6, a precision four-dimensional turntable 7, a crosshair target 6-2, a display control board 8, a test computer 9 and test software and a television monitor 10 is used to adjust the image of the crosshair target board 6-2 and the electrical crosshair of the low-light camera assembly 2 to coincide, thereby completing the full alignment of the optical axis and visual axis of the continuous zoom television camera.

[0021] Specifically, a method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera comprises the following steps: Step 1: Build the alignment adjustment and detection system of the optical axis and visual axis of the continuous zoom TV camera.

[0022] according to Figure 1As shown, the optical axis and visual axis alignment adjustment and detection system of the continuous zoom TV camera includes a continuous zoom TV camera 5, an optical bench 6 including a collimator 6-1, a crosshair target plate 6-2, a light source 6-3 and a measuring microscope 6-4, a precision four-dimensional turntable 7, a display control board 8, a test computer 9 and a TV monitor 10. The continuous zoom TV camera 5 is fixed to the precision four-dimensional turntable 7 through a flange, and the precision four-dimensional turntable 7 is fixed to the guide rail of the optical bench 6 through a dovetail groove structure, and can be conveniently adjusted to be optically coaxial with the collimator 6-1 and the measuring microscope 6-4 of the optical bench 6. The camera component 2, the video acquisition display and motor control component 4, the display control board 8, the TV monitor 10 and the test computer 9 of the continuous zoom TV camera 5 are electrically connected.

[0023] The low-light-level continuous zoom lens 1 is connected with the low-light-level camera component 2, the motor component 3, and the video acquisition display and motor control component 4 to form a continuous zoom television camera 5.

[0024] The light source 6-3 of the optical bench 6 illuminates the crosshair target plate 6-2, and the parallel light tube 6-1 collimates the imaging light transmitted by the crosshair target plate 6-2 to form an image projected to infinity. The image is taken as an object by the continuous zoom television camera 5 and converged into an image of the crosshair target plate 6-2 on its focal plane. There are two ways to observe the image: one is to directly observe using a measuring display mirror; the other is to use a low-light camera component to receive the image of the crosshair target plate and convert the optical signal into an electrical signal, and then use the video acquisition display and motor control component 4 to collect the electrical signal output by the low-light camera component, and transmit it to the display control board 8 after image preprocessing. The display control board 8 drives the television monitor 10 to display the image of the crosshair target plate, and the debugging personnel can observe through the monitor.

[0025] Furthermore, the test computer 9 runs the test software and transmits the instructions to the display control board 8 through the CAN bus. The display control board 8 drives the zoom motor or the focus motor or the filter switching motor through the video acquisition display and motor control component 4 to achieve the zoom or focus or filter switching of the continuous zoom TV camera 5.

[0026] Step 2: Align and adjust the optical axis and visual axis of the continuous zoom television camera throughout the zoom process.

[0027] according to Figure 1As shown, the first step is to make the optical axis of the collimator 6-1 coincide with the optical axis of the continuous zoom lens 1. First, the low-light continuous zoom lens 1 is placed between the collimator 6-1 and the measuring microscope 6-4. The crosshair graticule target plate 6-2 is placed on the focal plane of the collimator 6-1. The relative position and angle of the precision four-dimensional turntable 7 and the measuring microscope 6-4 are adjusted until the clarity of the crosshair image of the graticule formed at the long focal end of the continuous zoom lens observed through the measuring microscope 6-4 meets the preset requirements; then the continuous zoom lens is adjusted to the short focal end through the zoom cam, and the measuring microscope 6-4 is used to adjust the zoom lens to the short focal end. Observe the cross-line image of the graticule through mirror 6-4 and mark its position in the image plane. Of course, if the picture clarity is too low, it can be adjusted through the focusing assembly to achieve clear identification; then adjust the continuous zoom lens to the telephoto end through the magnification cam again, and adjust the cross-line image of the graticule at the telephoto end to the marked cross-line image position of the graticule at the short focal end by adjusting the precision four-dimensional turntable 7; repeat this adjustment until the cross-line image positions of the graticule formed by the telephoto end and the short focal end of the continuous zoom lens remain coincident, at which time the optical axis of the parallel light tube 6-1 coincides with the optical axis of the continuous zoom lens 1.

[0028] The second step is to determine the focus zero position and the image plane position of the low-light continuous zoom lens. First, adjust the continuous zoom lens 1 to the telephoto end through the zoom cam, and adjust the measuring microscope 6-4 until the crosshair image of the graticule meets the preset requirements; then adjust the continuous zoom lens to the short focal end through the zoom cam, and use the measuring microscope to observe the crosshair image of the graticule at this time. If the image clarity does not meet the requirements, use the focusing group to focus until the image clarity meets the requirements; then adjust the continuous zoom lens to the telephoto end again, and use the measuring microscope to observe the crosshair image of the graticule. If it does not meet the clarity requirements, repeat the above process until it meets the requirements. Then fix the focusing group and mark the position of the focusing group, which is the focus zero position, and the focal plane position of the measuring microscope at this time is the image plane position of the continuous zoom lens.

[0029] The third step is to align and adjust the optical axis and visual axis of the continuous zoom TV camera 1. First, the flange structure is used in combination with gaskets to fine-tune the camera component 2 to ensure that the photosensitive surface of the camera component 2 coincides with the image surface of the continuous zoom lens 1; then the test software is run on the test computer 9 to issue instructions, which are passed to the display control board 8. The display control board 8 controls the camera component 2 to display the electric crosshairs on the TV monitor 10 through the video acquisition display and motor control component 4; at the same time, the reticle crosshairs 6-2 at the focal plane of the parallel light tube 6-1 are imaged on the camera component 2 through the continuous zoom TV camera lens, and the TV monitor 10 is driven by the video acquisition and motor control component 4 for display.

[0030] Normally, there is a difference in the position of the electric crosshairs and the grating crosshairs image displayed on the TV monitor 10. In order to eliminate the position difference, the optical axis and the visual axis of the continuous zoom TV camera 1 need to be aligned. First, the continuous zoom TV camera 1 is adjusted to the short focal end by using the zoom cam, and then the radial position of the camera assembly 2 is adjusted to make the grating crosshairs image displayed on the TV monitor 10 coincide with the electric crosshairs; then the continuous zoom TV camera 1 is adjusted to the long focal end by using the zoom cam, and the coincidence of the electric crosshairs and the grating crosshairs image displayed on the TV monitor 10 is observed. If there is a position difference, the electric crosshairs and the grating crosshairs image displayed on the TV monitor 10 are made to coincide with each other by adjusting the precision four-dimensional turntable 7, until the electric crosshairs and the grating crosshairs image displayed on the TV monitor 10 always coincide with each other in the two states of the continuous zoom TV camera 1 at the long focal end and the short focal end.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A system for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera, characterized in that: The system includes a zoom television camera, an optical bench, a four-dimensional turntable, a display control board, a test computer and a television monitor, wherein the optical bench includes a collimator, a crosshair target plate, a light source and a measuring microscope. The light source of the optical bench illuminates the crosshair target plate, and the collimator collimates the imaging light transmitted by the crosshair target plate to form an image projected to infinity. The image is taken as an object by the continuous zoom television camera and converged into an image of the crosshair target plate on its focal plane.

2. The optical axis and visual axis alignment and adjustment system of a continuous zoom television camera according to claim 1, characterized in that: The connected zoom television camera is composed of a low-light-level continuous zoom lens, a low-light-level camera component, a motor component, and a video acquisition display and motor control component.

3. The optical axis and visual axis alignment and adjustment system of a continuous zoom television camera according to claim 1, characterized in that: The continuous zoom television camera is fixed on the precision four-dimensional turntable through a flange, and the precision four-dimensional turntable is fixed on the guide rail of the optical bench through a dovetail groove structure and adjusted to be optically coaxial with the parallel light tube of the optical bench and the measuring microscope.

4. The optical axis and visual axis alignment and adjustment system of a continuous zoom television camera according to claim 1, characterized in that: The camera assembly of the continuous zoom television camera, the video acquisition display and motor control assembly, the display control board, the television monitor and the test computer are electrically connected.

5. A method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera, characterized in that: The following steps are involved: S1. Build a system for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera as described in any one of claims 1 to 4; S2, alignment and adjustment of the optical axis and visual axis of the continuous zoom television camera throughout the zoom process; The specific steps of S2 include S21, adjusting so that the optical axis of the collimator coincides with the optical axis of the zoom lens; S22, determining the focus zero position and the image plane position of the low-light level continuous zoom lens; S23. Align and adjust the optical axis and visual axis of the continuous zoom television camera to ensure that the crosshair image of the reticle and the electric crosshair of the continuous zoom television camera remain consistent throughout the zooming process.

6. A method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera according to claim 5, characterized in that: The specific steps of S21 include S211. First, place the low-light level continuous zoom lens between the collimator and the measuring microscope, place a crosshair graticule target plate on the focal plane of the collimator, and adjust the relative position and angle of the precision four-dimensional turntable and the measuring microscope until the clarity of the crosshair image of the graticule formed by the telephoto end of the continuous zoom lens observed through the measuring microscope meets the preset requirements; S212, adjusting the zoom lens to the short focal end through the zoom cam, observing the crosshair image of the reticle through the measuring microscope, and marking its position in the image plane. If the image clarity is too low, adjusting it through the focusing assembly to achieve clear recognition; then adjusting the zoom lens to the long focal end through the zoom cam again, and adjusting the crosshair image of the reticle at the long focal end to the position of the crosshair image marked at the short focal end by adjusting the precision four-dimensional turntable; S213, repeatedly adjusting in this way until the positions of the cross-line images of the graticule formed by the long focal end and the short focal end of the continuous zoom lens remain coincident, and at this time, the optical axis of the collimator coincides with the optical axis of the continuous zoom lens.

7. A method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera according to claim 5, characterized in that: The specific steps of S22 include S221. First, adjust the continuous zoom lens to the telephoto end through the zoom cam, and adjust the measuring microscope until the clarity of the cross-line image of the reticle meets the preset requirements; S222, then adjust the continuous zoom lens to the short focal end through the zoom cam, and observe the cross-line image of the reticle with the measuring microscope. If the image clarity does not meet the requirements, use the focus group to adjust the focus until the image clarity meets the requirements; Then adjust the zoom lens to the telephoto end again, and use the measuring microscope to observe the clarity of the reticle crosshair image. If it does not meet the clarity requirements, repeat the above process until it meets the requirements. S223. Finally, fix the focus group and mark the position of the focus group, which is the focus zero position. At this time, the focal plane position of the measuring microscope is the image plane position of the continuous zoom lens.

8. The method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera according to claim 5, characterized in that: The specific steps of S23 include S231, firstly, the flange structure is used in combination with a gasket to fine-tune the camera assembly to ensure that the photosensitive surface of the camera assembly coincides with the image surface of the continuous zoom lens; S232, then run the test software on the test computer to issue a command, and pass it to the display control board, which controls the camera component to display the electric crosshairs on the TV monitor through the video acquisition display and motor control component. At the same time, the crosshairs of the reticle at the focal plane of the collimator are imaged on the camera component through the continuous zoom TV camera lens, and the TV monitor is driven to display through the video acquisition and motor control component; S233. In view of the difference between the positions of the reticle crosshairs and the electric crosshairs, the precise four-dimensional turntable and the camera assembly are adjusted in coordination to achieve that the reticle crosshairs and the electric crosshairs of the continuous zoom television camera are always consistent throughout the zoom range.

9. A method for aligning and adjusting the optical axis and visual axis of a continuous zoom television camera according to claim 8, characterized in that: In step S233, in order to eliminate the difference between the position of the reticle crosshair image and the electric crosshair, it is necessary to align the optical axis and the visual axis of the continuous zoom television camera. The specific steps include: First, the zoom TV camera is adjusted to the short focal length using the zoom cam, and then the radial position of the camera assembly is adjusted so that the reticle crosshair image displayed on the TV monitor coincides with the electric crosshair; Then use the zoom cam to adjust the continuous zoom TV camera to the telephoto end, observe the overlap of the electric crosshairs and the reticle crosshairs displayed on the TV monitor, if there is a position difference, adjust the precision four-dimensional turntable to make the electric crosshairs and the reticle crosshairs displayed on the TV monitor overlap, until the continuous zoom TV camera is at the telephoto end and the short focal end, the electric crosshairs and the reticle crosshairs displayed on the TV monitor always overlap.

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