CN117635727A - Method for assisting camera calibration by using acceleration sensor - Google Patents
Method for assisting camera calibration by using acceleration sensor Download PDFInfo
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- CN117635727A CN117635727A CN202311592447.8A CN202311592447A CN117635727A CN 117635727 A CN117635727 A CN 117635727A CN 202311592447 A CN202311592447 A CN 202311592447A CN 117635727 A CN117635727 A CN 117635727A
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Abstract
The invention discloses a method for calibrating an auxiliary camera by using an acceleration sensor, which comprises the steps of obtaining an X-axis acceleration value and a Y-axis acceleration value of the acceleration sensor, drawing a two-axis plane and displaying the position of the acceleration value; performing plane alignment adjustment on the equipment, wherein the position of the acceleration value is in a set correction range; according to the acceleration value, a physical correction method or a software algorithm correction method is adopted to correct the image shot by the camera to reach a horizontal state; monitoring the acceleration value of an acceleration sensor of the equipment in real time, and sending out early warning to remind a user to perform plane alignment adjustment when the position of the acceleration value exceeds a set correction range; and when the acceleration value is not exceeded, performing horizontal correction by using the latest acceleration value acquired by the acceleration sensor. The invention solves the problems of accuracy of single-axis calibration and difficult control in four-angle calibration, solves the problem of early warning after calibration, and realizes more accurate and easy-to-use camera measurement calibration function.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to a method for calibrating a camera by using an acceleration sensor.
Background
More and more methods for calibrating by using image recognition are used for completing accurate fixed-point tasks in scenes measured by using cameras. The common implementation method comprises the following steps: 1. drawing a horizontal line on the image and manually aligning the prefabricated marking lines; 2. and identifying the preset identification characteristic alignment marked line by utilizing an image identification technology.
The two methods have the defects that: 1) Typically only one direction is calibrated (uniaxial calibration). If the calibration in the horizontal direction is successful, it is not clear whether the vertical direction is in an aligned state (as shown in fig. 1), and the measurement result has a large deviation; 2) Meanwhile, the difficulty in calibrating the horizontal direction and the vertical direction is high. For example, when using image recognition technology to perform the quadrangle calibration, it is difficult to adjust the device to perform the translation while being in the horizontal posture (as shown in fig. 2); 3) After calibration, the function of deflecting the gesture of the early warning equipment is not provided. In the scene of camera measurement calibration, the reasons why the alignment difficulty of using the marked lines or the alignment of multiple marked points is high are as follows: 1) In general, the calibration personnel manually calibrate when not determining whether the level, and the requirement on the calibration personnel is high; 2) After calibration, calibration personnel are generally required to monitor whether the equipment gesture deflects at any time, whether the calibration is accurate, and the concentration requirement on personnel is higher.
In conclusion, the two camera calibration methods have the problems that the calibration vertical axis is inaccurate, the calibration difficulty is high, the gesture deflection cannot be early warned after the calibration, the manual requirement is high, and the use scene of the normalized high-accuracy measurement is difficult to realize.
Disclosure of Invention
The invention aims to provide a method for assisting in camera calibration by using an acceleration sensor, which is used for solving the problems that in the existing camera calibration method, a calibration vertical axis is inaccurate, the calibration difficulty is high, gesture deflection cannot be early-warned after calibration, the manual requirement is high, the use scene of normalized high-accuracy measurement is difficult to realize, and the post-calibration early warning is not carried out.
The invention solves the problems by the following technical proposal:
a method for assisting camera calibration using an acceleration sensor, comprising:
s1, acquiring an X-axis acceleration value and a Y-axis acceleration value of an acceleration sensor in equipment where a camera is located;
s2, drawing a two-axis plane by utilizing the X-axis acceleration value and the Y-axis acceleration value, and displaying the positions of the X-axis acceleration value and the Y-axis acceleration value; performing plane alignment adjustment on the equipment to enable the positions of the X-axis acceleration value and the Y-axis acceleration value to be in a set correction range;
step S3, after the equipment reaches the plane alignment, carrying out horizontal correction on the equipment: according to the X-axis acceleration value and the Y-axis acceleration value, a physical correction method or a software algorithm correction method is adopted to correct the image shot by the camera to reach a horizontal state;
s4, monitoring an X-axis acceleration value and a Y-axis acceleration value of an acceleration sensor of the equipment in real time, and sending out early warning to remind a user to adjust the plane alignment when the positions of the X-axis acceleration value and the Y-axis acceleration value are beyond the set correction range; when the positions of the X-axis acceleration value and the Y-axis acceleration value do not exceed the set correction range, the latest X-axis acceleration value and the latest Y-axis acceleration value acquired by the acceleration sensor are used for horizontal correction by adopting a physical correction method or a software algorithm correction method.
In the process of calibrating by using the camera, the invention uses the acceleration sensor to explicitly mark the X-axis and Y-axis directional offset, and controls the total offset within a set reasonable range. And meanwhile, the calculation result is fed back to the camera control part, so that the calibration precision is increased, the calibration difficulty is reduced, the value of the acceleration sensor is monitored in real time, and the offset of the equipment is early-warned. The two-axis calibration and the numerical overrun provided by the acceleration sensor send out early warning information, so that a measure of horizontal correction is provided, the calibration difficulty during measurement is reduced, and the calibration precision is improved. The method solves the problem that the existing implementation method does not have post-calibration early warning.
Further, the physical correction method specifically includes: the X-axis acceleration value and the Y-axis acceleration value are arranged in the camera module, and the camera module drives the voice coil motor according to the X-axis acceleration value and the Y-axis acceleration value to enable the lens to undergo reverse physical deflection, so that the final imaging of the camera and the actual punctuation reach a horizontal state.
Further, the software algorithm correction method comprises the following steps: and stretching and deflecting the picture shot by the camera from the image display to enable the image to reach a horizontal state.
Further, the software algorithm correction method comprises the following steps: and correcting the measured data from the test result by using a formula Y=X- |A|A, so that the final test result is corrected to a value close to the actual data, wherein Y is the final result, A is the deflection, X is the measured value, and the deflection is calculated by an X-axis acceleration value and a Y-axis acceleration value.
Compared with the prior art, the invention has the following advantages:
(1) The method provided by the invention judges whether the acquired acceleration sensor numerical display is in a limiting area, and assists the calibration personnel to keep the equipment in a modifiable range in an overrun early warning mode. Therefore, the difficulty in the measurement and calibration of the camera is solved, the work concentration loss of calibration personnel is reduced, the accuracy of overall measurement data is improved, and the blank of realizing the measurement and calibration of the camera in the use scene is filled.
(2) According to the invention, the early warning information is sent out through the two-axis calibration and the numerical overrun provided by the acceleration sensor, the measure of horizontal correction is provided, the calibration difficulty during measurement is reduced, the calibration precision is improved, and the requirement that personnel need to monitor the equipment posture at any time after calibration is reduced.
(3) The method solves the problem of accuracy of single-axis calibration and the problem of difficult control in four-angle calibration in the existing implementation method, solves the problem that the prior art does not have early warning after calibration, and realizes a more accurate and easy-to-use camera measurement calibration function.
Drawings
FIG. 1 is a schematic diagram of a prior art technique using single axis (horizontal) calibration;
FIG. 2 is a schematic diagram of a four corner calibration in the prior art;
FIG. 3 is a flow chart of the present invention;
FIG. 4 is a schematic diagram of a common coordinate system of an acceleration sensor;
FIG. 5 is a schematic diagram of horizontal alignment;
FIG. 6 is a schematic diagram of camera correction;
wherein the a-acceleration data shows a status circle; b-early warning range circle; c-axial number.
Detailed Description
The present invention will be described in further detail with reference to examples, but embodiments of the present invention are not limited thereto.
Examples:
referring to fig. 3, a method for calibrating a camera with the assistance of an acceleration sensor includes: acceleration sensor, plane alignment, horizontal correction, overrun early warning and auxiliary calibration specifically include:
1. acquiring an acceleration value of an acceleration sensor in the X axis and the Y axis of equipment:
the debugging personnel oppositely measures the equipment (such as a seat body forward-bending measuring plate) and acquires data of an acceleration sensor of the equipment in real time, wherein the data generally comprise X, Y, Z axial data; the device acquires values of the acceleration sensor, which typically contains X, Y, Z axis direction data, as shown in fig. 4. The invention ignores the axial (generally Z-axis) data shot by the camera and uses the other two axes (generally X-axis and Y-axis) perpendicular to the shooting axis.
2. Plane alignment
As shown in fig. 5, drawing a two-axis plane using the obtained X-axis and Y-axis data includes: acceleration data display state circle a and early warning range circle b (the acceleration data display state circle is obtained by the point values of X-axis and Y-axis data, and is displayed as a circle for the convenience of clear checking by calibration personnel, the early warning range circle is the modifiable range of the X-axis and Y-axis data), and the axial values c of the X-axis and Y-axis, and by utilizing the obtained data and the graph display result, equipment debugging personnel adjusts the equipment into a horizontal modifiable range, namely an early warning range circle (the horizontal modifiable range refers to the acceptable or adjustable horizontal error range when the camera is calibrated).
3. Level correction
When the apparatus reaches horizontal alignment, the apparatus is generally not at absolute level, and a level correction method is required. There are two ways of horizontal correction: physical corrections and software algorithm corrections.
3.1, the principle of the physical correction is to actively reverse deflect the lens by using a camera module motor, as shown in fig. 6. The device sets the value of the acceleration sensor in the camera module, and the camera module drives the voice coil motor by using the data to enable the lens to reversely and physically deflect, so that the final imaging of the camera and the actual punctuation reach a horizontal state with very high precision.
For example: when the current equipment reaches a horizontal alignment state, deflection of +0.3 angle units is respectively arranged on an X axis, at the moment, a motor deflects a lens by-0.3 angle units, and finally imaging and actual punctuation of a camera are in a horizontal state.
3.2, correcting by a software algorithm, namely stretching and deflecting a picture shot by a camera from display so as to enable the image to reach a horizontal state; and secondly, using a formula Y=X- |A|A (Y is a final result, A is a deflection amount and X is a measured value) to correct the final test result to be equal to or close to the actual data from the test result.
For example, there is a deflection of +0.3 angular units in the X-axis direction when the current device reaches a horizontally aligned state, the measurement at this time showing 30.00CM. Because the device is actually deflected backwards in a direction perpendicular to the X-axis, the measured value will be larger than the actual value. The final correction result was calculated to be 29.91CM.
4. Overrun early warning
The data of the acceleration sensor is still monitored in real time after the device is in horizontal alignment. When the value of the acceleration sensor does not exceed the modifiable horizontal range, providing the latest data acquired by the sensor to a camera or a correction algorithm for horizontal correction; when the value of the acceleration sensor exceeds the modifiable horizontal range, an early warning is sent to ask the debugging personnel to carry out the planar alignment task again.
5. Auxiliary calibration
When the equipment is horizontally modified, the calibration task of shooting the image by the camera can be realized more easily.
Furthermore, the calibration and measurement can be started more easily through the corrected equipment;
the invention can assist the camera to realize the effects of calibration and real-time early warning calibration more easily, and solves the problems of difficult calibration and no equipment deflection early warning function of the existing scheme.
Although the invention has been described herein with reference to the above-described illustrative embodiments thereof, the above-described embodiments are merely preferred embodiments of the present invention, and the embodiments of the present invention are not limited by the above-described embodiments, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure.
Claims (4)
1. A method for assisting camera calibration using an acceleration sensor, comprising:
s1, acquiring an X-axis acceleration value and a Y-axis acceleration value of an acceleration sensor in equipment where a camera is located;
s2, drawing a two-axis plane by utilizing the X-axis acceleration value and the Y-axis acceleration value, and displaying the positions of the X-axis acceleration value and the Y-axis acceleration value; performing plane alignment adjustment on the equipment to enable the positions of the X-axis acceleration value and the Y-axis acceleration value to be in a set correction range;
step S3, after the equipment reaches the plane alignment, carrying out horizontal correction on the equipment: according to the X-axis acceleration value and the Y-axis acceleration value, a physical correction method or a software algorithm correction method is adopted to correct the image shot by the camera to reach a horizontal state;
s4, monitoring an X-axis acceleration value and a Y-axis acceleration value of an acceleration sensor of the equipment in real time, and sending out early warning to remind a user to adjust the plane alignment when the positions of the X-axis acceleration value and the Y-axis acceleration value are beyond the set correction range; when the positions of the X-axis acceleration value and the Y-axis acceleration value do not exceed the set correction range, the latest X-axis acceleration value and the latest Y-axis acceleration value acquired by the acceleration sensor are used for horizontal correction by adopting a physical correction method or a software algorithm correction method.
2. The method for calibrating an auxiliary camera using an acceleration sensor according to claim 1, wherein the physical correction method specifically comprises: the X-axis acceleration value and the Y-axis acceleration value are arranged in the camera module, and the camera module drives the voice coil motor according to the X-axis acceleration value and the Y-axis acceleration value to enable the lens to undergo reverse physical deflection, so that the final imaging of the camera and the actual punctuation reach a horizontal state.
3. A method for calibrating an auxiliary camera using an acceleration sensor according to claim 1 or 2, wherein the software algorithm correction method is as follows: and stretching and deflecting the picture shot by the camera from the image display to enable the image to reach a horizontal state.
4. A method for calibrating an auxiliary camera using an acceleration sensor according to claim 1 or 2, wherein the software algorithm correction method is as follows: and correcting the measured data from the test result by using a formula Y=X- |A|A, so that the final test result is corrected to a value close to the actual data, wherein Y is the final result, A is the deflection, X is the measured value, and the deflection is calculated by an X-axis acceleration value and a Y-axis acceleration value.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311592447.8A CN117635727A (en) | 2023-11-27 | 2023-11-27 | Method for assisting camera calibration by using acceleration sensor |
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| CN202311592447.8A CN117635727A (en) | 2023-11-27 | 2023-11-27 | Method for assisting camera calibration by using acceleration sensor |
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| CN117635727A true CN117635727A (en) | 2024-03-01 |
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| CN202311592447.8A Pending CN117635727A (en) | 2023-11-27 | 2023-11-27 | Method for assisting camera calibration by using acceleration sensor |
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