CN113824942B - Trapezoidal correction method, apparatus, projector, and computer-readable storage medium - Google Patents
Trapezoidal correction method, apparatus, projector, and computer-readable storage medium Download PDFInfo
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- CN113824942B CN113824942B CN202111242419.4A CN202111242419A CN113824942B CN 113824942 B CN113824942 B CN 113824942B CN 202111242419 A CN202111242419 A CN 202111242419A CN 113824942 B CN113824942 B CN 113824942B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3179—Video signal processing therefor
- H04N9/3185—Geometric adjustment, e.g. keystone or convergence
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3191—Testing thereof
Abstract
The application is applicable to the technical field of projectors, and provides a trapezoidal correction method, a trapezoidal correction device, a projector and a computer readable storage medium, wherein the trapezoidal correction method is applied to the projector, the projector comprises an inertial sensor, and the trapezoidal correction method comprises the following steps: obtaining calibration parameters calibrated in advance, wherein the calibration parameters comprise the calibration gesture of the projector; when the change of the posture of the projector is detected through the inertial sensor, calculating a plane inclination angle between a first projection plane and a second projection plane, wherein the first projection plane is a projection plane after the change of the posture of the projector, and the second projection plane is a projection plane before the change of the posture of the projector; determining an attitude inclination angle of the projector according to the plane inclination angle; and carrying out trapezoidal correction according to the calibration posture and the posture inclination angle of the projector. By the method, the accuracy of trapezoid correction can be effectively improved.
Description
Technical Field
The present application relates to a trapezoidal correction method, a trapezoidal correction device, a projector, and a computer readable storage medium.
Background
During use of the projector, the following often occurs: because of the change of the placement position of the projector or the change of the projection environment, the position of the projector is not perpendicular to the projection curtain, so that the keystone distortion of a projection picture is generated, the projection picture is distorted, and the user experience is affected. Therefore, the trapezoidal correction function of the projector is particularly important.
In the conventional trapezoidal correction method, a specific pattern is projected onto a projection screen, a projection screen of the specific pattern is obtained by a camera on a projector, and trapezoidal correction is performed based on the projection screen. When the distance between the optical machine and the camera on the projector is relatively short or light interference exists, the camera cannot acquire the accurate projection picture of the specific graph, so that the trapezoidal correction effect is poor.
Disclosure of Invention
The embodiment of the application provides a trapezoid correction method, a trapezoid correction device, a projector and a computer readable storage medium, which can effectively improve the accuracy of trapezoid correction.
In a first aspect, an embodiment of the present application provides a trapezoidal correction method, which is applied to a projector, where the projector includes an inertial sensor, and the method includes:
obtaining calibration parameters calibrated in advance, wherein the calibration parameters comprise the calibration gesture of the projector;
when the change of the posture of the projector is detected through the inertial sensor, calculating a plane inclination angle between a first projection plane and a second projection plane, wherein the first projection plane is a projection plane after the change of the posture of the projector, and the second projection plane is a projection plane before the change of the posture of the projector;
determining an attitude inclination angle of the projector according to the plane inclination angle;
and carrying out trapezoidal correction according to the calibration posture and the posture inclination angle of the projector.
In the embodiment of the application, the posture change of the projector is monitored through the inertial sensor, and when the posture of the projector is changed, the trapezoidal correction is performed by calculating the plane inclination angle between the first projection plane and the second projection plane before and after the posture change of the projector, so that the original projection task is not required to be interrupted, and the user experience is effectively improved. In addition, in the method, the projection picture is not required to be acquired, only the projection plane is required to be determined, errors of the projection picture caused by light interference and other conditions are avoided, and the accuracy of trapezoid correction is effectively improved.
In a possible implementation manner of the first aspect, the calculating a plane inclination angle between the first projection plane and the second projection plane includes:
calculating a first plane equation of the first projection plane;
acquiring a second plane equation of the second projection plane;
the plane tilt angle is calculated from the first plane equation and the second plane equation.
In a possible implementation manner of the first aspect, the projector further includes a ranging sensor, and the pre-calibrated calibration parameter includes a light emitting direction vector of the ranging sensor in a first coordinate system, where the first coordinate system is a coordinate system where the projector is located;
the calculating a first plane equation for the first projection plane includes:
acquiring a first gravity vector in the first coordinate system;
obtaining distance measurement distances between two preset calibration points on the first projection plane and the projector respectively through the distance measurement sensor, wherein the preset calibration points are determined by the light emitting direction vector;
calculating respective projection coordinates of the two preset calibration points in the first coordinate system according to the light-emitting direction vector and the distance measurement distance;
and calculating the first plane equation according to the first gravity vector and the respective projection coordinates of the two preset calibration points in the first coordinate system.
In a possible implementation manner of the first aspect, the pre-calibrated calibration parameters include a transformation matrix between a world coordinate system and the first coordinate system;
the acquiring a first gravity vector in the first coordinate system includes:
acquiring a second gravity vector in the world coordinate system through the inertial sensor;
and converting the second gravity vector into a first gravity vector in the first coordinate system according to the transformation matrix.
In a possible implementation manner of the first aspect, the calculating the first plane equation according to the first gravity vector and the respective projection coordinates of the two preset calibration points in the first coordinate system includes:
calculating a first plane vector according to respective projection coordinates of the two preset calibration points in the first coordinate system;
calculating a second plane vector according to the first gravity vector;
the first plane equation is calculated from the first plane vector and the second plane vector.
In a possible implementation manner of the first aspect, the calculating the plane tilt angle according to the first plane equation and the second plane equation includes:
determining a first normal vector of the first plane equation;
determining a second normal vector of the second plane equation;
calculating a vector included angle between the first normal vector and the second normal vector;
and determining the vector included angle as the plane inclined angle.
In a possible implementation manner of the first aspect, the performing trapezoidal correction according to the calibration pose and the pose inclination angle of the projector includes:
calculating the current posture of the projector according to the calibration posture and the posture inclination angle of the projector;
calculating vertex coordinates of a projection area according to the current projection gesture and the projection ratio;
and carrying out trapezoidal correction according to the vertex coordinates.
In a second aspect, an embodiment of the present application provides a trapezoidal correction device, including: applied to a projector including an inertial sensor, the apparatus comprising:
the parameter acquisition module is used for acquiring calibration parameters calibrated in advance, wherein the calibration parameters comprise the calibration gesture of the projector;
the angle calculation module is used for calculating a plane inclination angle between a first projection plane and a second projection plane when the change of the posture of the projector is detected through the inertial sensor, wherein the first projection plane is a projection plane after the change of the posture of the projector, and the second projection plane is a projection plane before the change of the posture of the projector;
an angle determining module for determining an attitude inclination angle of the projector according to the plane inclination angle;
and the trapezoid correction module is used for performing trapezoid correction according to the calibration posture and the posture inclination angle of the projector.
In a third aspect, an embodiment of the present application provides a projector, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the trapezoid correction method according to any of the first aspect when executing the computer program.
In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, where a computer program is stored, where the computer program, when executed by a processor, implements a trapezoidal correction method according to any one of the first aspects above.
In a fifth aspect, an embodiment of the present application provides a computer program product for, when run on a terminal device, causing the terminal device to perform the trapezoid correction method according to any of the first aspects.
It will be appreciated that the advantages of the second to fifth aspects may be found in the relevant description of the first aspect, and are not described here again.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a trapezoidal correction system provided by an embodiment of the present application;
FIG. 2 is a schematic diagram of a calibration scenario provided by an embodiment of the present application;
FIG. 3 is a schematic flow chart of a trapezoid correction method according to an embodiment of the present application;
FIG. 4 is a schematic view of a projection plane provided by an embodiment of the present application;
FIG. 5 is a schematic diagram of a calibration pattern provided by an embodiment of the present application;
FIG. 6 is a schematic diagram of feature points on a calibration pattern provided by an embodiment of the present application;
FIG. 7 is a block diagram showing a configuration of a trapezoidal correction device according to an embodiment of the present application;
fig. 8 is a schematic structural diagram of a projector according to an embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Furthermore, the terms "first," "second," "third," and the like in the description of the present specification and in the appended claims, are used for distinguishing between descriptions and not necessarily for indicating or implying a relative importance.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise.
Referring to fig. 1, a schematic diagram of a trapezoidal correction system according to an embodiment of the present application is provided. As shown in fig. 1, the trapezoidal correction system may include a projector 11, a calibration device 12, and a center console 13. The center console is respectively in communication connection with the projector and the calibration device.
In one embodiment, the calibration device may include a camera set and an electric rotating stage. The projector may include inertial sensors (IMU, inertial Measurement Unit) and ranging sensors (e.g., TOF (Timeof flight) sensors). The projector is placed on an electric rotating table of the calibration device. The center console performs pre-calibration on the projector through the calibration device to obtain pre-calibrated calibration parameters, and sends the calibration parameters to the projector. The projector performs automatic trapezoidal correction using calibration parameters and data obtained by the inertial sensor and the ranging sensor.
In an application scenario, referring to fig. 2, a schematic diagram of a calibration scenario provided by an embodiment of the present application is shown. In this scenario, the pre-calibrated procedure may include: the projector projects a preset calibration pattern onto the projection curtain/wall. The camera set on the calibration device is matched with the electric rotating table to automatically find 0-bit alignment. The electric rotating table controls the projector to rotate along the pitching direction, and the center console obtains a projection image through the camera group on the calibration device when the projector rotates by a specific angle. The electric rotating table controls the projector to rotate along the left-right direction, and the center console obtains a projection image through the camera group on the calibration device when the projector rotates by a specific angle. The central console inputs the obtained projection image into an OpenCV library function/MATLAB tool box to extract characteristic points of the image, and calculates to obtain a homography matrix between a world coordinate system and a pixel coordinate system. The projector sends TOF data and IMU data corresponding to each of a plurality of angles (such as zero degrees and 20 degrees) to the center console. The center console calculates calibration parameters, such as yaw (i.e., left-right direction) unit vectors, pitch (i.e., pitch direction) unit vectors, and a transformation matrix between the world coordinate system and the projector coordinate system, based on the obtained homography matrix, the obtained TOF data, and the IMU data.
Through the embodiment, the calibration device is arranged outside the projector, so that the device cost of the projector is reduced. Parameter calibration is performed in advance, parameter calibration is not needed in the automatic trapezoidal correction process of the projector, trapezoidal correction is performed by using the calibrated parameters calibrated in advance, and trapezoidal correction time is effectively reduced. The trapezoidal correction method at the projector side is described below.
Referring to fig. 3, a schematic flow chart of a trapezoidal correction method according to an embodiment of the present application is provided, by way of example and not limitation, and the method may include the following steps:
s301, obtaining calibration parameters calibrated in advance.
The calibration parameters comprise the calibration posture of the projector. Specific calibration procedures can be seen from the description of the embodiments of fig. 1 and 2 above. The calibration pose of the projector may include a yaw (i.e., left-right direction) unit vector, a pitch (i.e., pitch direction) unit vector, and a transformation matrix between the world coordinate system and the projector coordinate system.
S302, when the change of the posture of the projector is detected by the inertial sensor, calculating the plane inclination angle between the first projection plane and the second projection plane.
The inertial sensor is a sensor mainly used for detecting acceleration and rotational motion. The principle is realized by adopting the law of inertia, and the principle is adopted from a microminiature MEMS sensor to a laser gyro with very high measurement accuracy, and no matter the size of the MEMS sensor is only a few millimeters, the principle is adopted from an optical fiber device with the diameter of nearly half a meter. Commonly used inertial sensors include accelerometers and angular velocity meters (gyroscopes), which are the core components of an inertial system and are the primary factors affecting the performance of the inertial system.
The inertial sensor is the basis for triggering auto-focus and trapezoidal correction. By detecting the change condition of the acceleration value in the IMU data, whether the position of the projection equipment changes in displacement or not can be judged. Whether the posture inclination angle of the projector changes can be judged by detecting the angular velocity value in the IMU data. Alternatively, an inertial sensor of the LSM6DS3TR-C type (comprising a combined unit consisting of a tri-axis gyroscope and a tri-axis accelerometer) can be used.
In one application scenario, when the data detected by the accelerometer and/or the angular velocity meter changes (for example, when the limited change value exceeds a preset value, it is determined that the data changes), that is, it is determined that the posture of the projector changes, at this time, the automatic trapezoidal correction function of the projector is started.
The first projection plane is a projection plane after the posture of the projector changes, and the second projection plane is a projection plane before the posture of the projector changes.
In one embodiment, calculating the plane tilt angle between the first projection plane and the second projection plane in S302 may include the steps of:
calculating a first plane equation of a first projection plane; acquiring a second plane equation of a second projection plane; the plane tilt angle is calculated from the first plane equation and the second plane equation.
Exemplary, referring to fig. 4, a schematic view of a projection plane provided by an embodiment of the present application is shown. In the embodiment of the application, the coordinate system of the projector is taken as a reference. As shown in fig. 4, the projection optical axis exits along the Z axis, the horizontal rightward direction is the X axis, and the vertical downward direction is the Y axis.
Alternatively, the calculation method of the first plane equation may include:
I. a first gravity vector in a first coordinate system is acquired.
Since the direction of the gravitational acceleration vector is always parallel to the wall surface, the direction of the gravitational force of the IMU can be translated onto the projection plane under the projector coordinate system along the Y-axis OB as shown in fig. 4. As described in the embodiment of fig. 2, the calibration parameters calibrated in advance include a transformation matrix between the world coordinate system and the first coordinate system. Accordingly, the acquiring of the first gravity vector may include: acquiring a second gravity vector in the world coordinate system through an inertial sensor; the second gravity vector is converted into a first gravity vector in the first coordinate system according to the transformation matrix.
Illustratively, the gravity data for the IMU are:
the gravity data of the IMU is transformed through a transformation matrix K, and the gravity vector under the projector coordinate system is obtained through the transformation from the world coordinate system to the projector coordinate system
Wherein, the liquid crystal display device comprises a liquid crystal display device,G cx 、G cy and G cz Gravity vector +.>Components in the respective coordinate axes of the projector coordinate system.
II. And acquiring the distance measurement distance between each of two preset calibration points on the first projection plane and the projector through a distance measurement sensor.
The calibration parameters calibrated in advance comprise the light emitting direction vector of the ranging sensor under a first coordinate system, wherein the first coordinate system is the coordinate system where the projector is located. The preset calibration point is determined by the light emitting direction vector.
The TOF sensor is used as a sensor for testing the distance, and different measuring areas can be divided in the TOF sensor, so that different area activations can be selected to conduct partition measurement, and depth information of different areas can be obtained. Alternatively, a VL53L1X (support area, single point ranging) model TOF sensor may be used.
Typically, the mounting angle θ of the TOF sensor L And theta R Is the light-emitting direction vector of the known quantity, namely TOF sensorAndis a known quantity. Correspondingly, the falling point of the ranging beam emitted by the TOF sensor on the projection plane is also determined, and the falling point is marked as a preset calibration point (as shown in points D and E in FIG. 4). Of course, as the projector posture changes, the position of the preset calibration point on the projection plane also changes accordingly.
Exemplary, light-emitting direction vectorAnd->The method comprises the following steps of:
wherein, the liquid crystal display device comprises a liquid crystal display device,and->Are unit vectors, i.e.)>
And III, calculating respective projection coordinates of the two preset calibration points in the first coordinate system according to the light emitting direction vector and the distance measurement distance.
Illustratively, as shown in fig. 4, the distance from the projector to the point D measured by the ranging sensor is L, and the distance to the point E is R. The projection coordinates of the point D and the point E under the first coordinate system are as follows:
and IV, calculating a first plane equation according to the first gravity vector and the respective projection coordinates of the two preset calibration points in the first coordinate system.
The manner in which the plane equation is calculated may include intercept, point French, general, and normal. Any of the above calculation methods may be employed, and the present application is not particularly limited.
The embodiment of the application provides a calculation mode of a plane equation: calculating a first plane vector according to respective projection coordinates of two preset calibration points in a first coordinate system; calculating a second plane vector according to the first gravity vector; the first plane equation is calculated based on the first plane vector and the second plane vector.
The principle that the plane equation of the plane can be determined according to two vectors on the same plane is that 2 coplanar vectors need to be constructed in order to solve the plane equation of the projection plane.
Exemplary, as shown in FIG. 4, vectorsOn the projection plane, the transformed gravity vector +.>Also in the projection plane. Thus, the plane equation can be solved from the two vectors. Specifically, the 2 coplanar vectors are respectively:
due to vectorsAnd->Coplanar, the plane formed by the two vectors is the first projection plane. The normal vector of the first projection plane must also be perpendicular to the plane formed by the two vectors. In other words, the normal vector of the first projection plane is perpendicular to the two vectors, so the cross product theorem is adopted +.>Obtaining a first Plane equation Plane1:a 1 x+b 1 y+c 1 z+d 1 =0. Normal vector of the first projection plane +.>The method comprises the following steps:
normal vector according to first projection planeThe coefficient a of the first plane equation can be determined 1 、b 1 、c 1 And d 1 . And further determine a first plane equation.
In the embodiment of the present application, the calculation mode of the second plane equation of the second projection plane is the same as the calculation mode of the first plane equation, and will not be described herein.
In one application scenario, before the pose of the projector changes, the projector may calculate the second plane equation at a preset period, that is, update the second plane equation at the preset period, and store the latest second plane equation in a storage medium of the projector. When the pose of the projector changes, the projector obtains a second plane equation from the storage medium.
In one embodiment, calculating the plane tilt angle from the first plane equation and the second plane equation may include:
determining a first normal vector of a first plane equation; determining a second normal vector of a second plane equation; calculating a vector included angle between the first normal vector and the second normal vector; the vector angle is determined as the plane tilt angle.
As can be seen from the above embodiments, the first Plane equation is calculated as Plane1:a 1 x+b 1 y+c 1 z+d 1 =0, from which a first normal vector can be obtained asSimilarly, assume that the second Plane equation obtained is Plane2:a 2 x+b 2 y+c 2 z+d 2 =0, from which a second normal vector can be obtained as +.>The included angle between the two normal vectors is:
s303, determining the posture inclined angle of the projector according to the plane inclined angle.
Alternatively, the attitude inclination angle of the projector may be made equal to the plane inclination angle. It is also possible to make the attitude inclination angle of the projector equal to the complement angle of the plane inclination angle.
S304, performing trapezoidal correction according to the calibration posture and posture inclination angle of the projector.
As described in the embodiment of fig. 1 and 2, during the pre-calibration process, the projector projects a preset calibration pattern (the calibration pattern may refer to the picture shown in fig. 5), and the camera acquires the projection image. In order to improve the recognition accuracy of the camera, a plurality of feature points (as shown in fig. 6) are generally set on the calibration chart. The electric rotating table controls the projector to rotate for one angle, and the camera acquires a corresponding projection image; and the central console calculates a transformation matrix K between the two images before and after the rotation of the projector according to the coordinates of the characteristic points on the projection image. Therefore, when the projector turns over the tilt angles cos θ of different angles to change the posture, there is a transformation matrix K matching with it.
After the pre-calibration process, the central console sends the calibrated calibration parameters to the projector, and the projector stores the calibration parameters. The calibration parameters comprise a plurality of groups of parameters, and each group of parameters comprises a calibration gesture (including a yaw value and a pitch value) and a transformation matrix K corresponding to the calibration gesture.
In the trapezoidal correction process of S304, the projector searches for a calibration posture (i.e., a yaw value and a pitch value) corresponding to the calculated posture-tilt angle cos from the storage medium, acquires a transformation matrix K corresponding to the calibration posture, and performs trapezoidal correction according to the acquired transformation matrix K. The specific correction procedure is as follows.
In one embodiment, one implementation of S304 is: calculating the current posture of the projector according to the calibration posture and the posture inclination angle of the projector; calculating corrected feature point coordinates according to the attitude inclination angle and the feature points on the projection picture; calculating vertex coordinates of the projection area according to the current gesture and the projection ratio of the projector, and defining the maximum projection area of the corrected projection picture; and determining the corrected projection picture according to the corrected characteristic point coordinates and the maximum projection area.
One implementation way of calculating the corrected feature point coordinates is as follows:
acquiring a target attitude (namely, a calibration attitude corresponding to an attitude inclination angle); obtaining a target matrix (namely a transformation matrix K corresponding to the target gesture); and calculating corrected feature point coordinates according to the target matrix and the feature points on the projection plane.
Specifically, the method for calculating the corrected feature point coordinates according to the feature points on the target matrix and the projection plane comprises the following steps:
assuming that the coordinates of a feature point a in one of the uncorrected front projection planes are a (x, y), the projection coordinates of a feature point a 'corresponding to the a point in the corrected projection plane are a' (x ', y'); according to the characteristic point coordinates A (x, y) and the corresponding transformation matrix K, the coordinates of the A' point in the corrected projection plane can be calculated and obtained: a ' (x ', y ')=k·a (x, y).
The projection ratio is the ratio of the projection distance to the width of the projection screen. The projection area can be determined according to the current gesture and the projection ratio of the projector, and then the vertex coordinates of the projection area (generally, the projection area is rectangular, namely, the coordinates of four vertices of the rectangle are calculated) are calculated, so that the projection area is defined.
To further increase the accuracy of the keystone correction, in one embodiment, a manual compounding may also be performed after the projector performs the automatic keystone correction. If the projection picture corrected by the projector is still inclined, the user can manually perform trapezoidal correction.
It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present application.
Corresponding to the trapezoid correcting method described in the above embodiment, fig. 7 is a block diagram of the configuration of the trapezoid correcting apparatus provided in the embodiment of the present application, and only the portions related to the embodiment of the present application are shown for convenience of explanation.
Referring to fig. 7, the apparatus includes:
the parameter obtaining module 71 is configured to obtain calibration parameters that are calibrated in advance, where the calibration parameters include a calibration gesture of the projector.
And an angle calculating module 72, configured to calculate, when the change in the posture of the projector is detected by the inertial sensor, a plane inclination angle between a first projection plane and a second projection plane, where the first projection plane is a projection plane after the change in the posture of the projector, and the second projection plane is a projection plane before the change in the posture of the projector.
An angle determination module 73 for determining an attitude inclination angle of the projector from the plane inclination angle.
A trapezoidal correction module 74 for performing trapezoidal correction according to the calibration attitude and the attitude inclination angle of the projector.
Optionally, the angle calculation module 72 is further configured to:
calculating a first plane equation of the first projection plane; acquiring a second plane equation of the second projection plane; the plane tilt angle is calculated from the first plane equation and the second plane equation.
Optionally, the projector further includes a ranging sensor, and the pre-calibrated calibration parameter includes a light emitting direction vector of the ranging sensor in a first coordinate system, where the first coordinate system is a coordinate system where the projector is located.
Accordingly, the angle calculation module 72 is further configured to:
acquiring a first gravity vector in the first coordinate system;
obtaining distance measurement distances between two preset calibration points on the first projection plane and the projector respectively through the distance measurement sensor, wherein the preset calibration points are determined by the light emitting direction vector;
calculating respective projection coordinates of the two preset calibration points in the first coordinate system according to the light-emitting direction vector and the distance measurement distance;
and calculating the first plane equation according to the first gravity vector and the respective projection coordinates of the two preset calibration points in the first coordinate system.
Optionally, the pre-calibrated calibration parameters include a transformation matrix between a world coordinate system and the first coordinate system.
Accordingly, the angle calculation module 72 is further configured to:
acquiring a second gravity vector in the world coordinate system through the inertial sensor; and converting the second gravity vector into a first gravity vector in the first coordinate system according to the transformation matrix.
Optionally, the angle calculation module 72 is further configured to:
calculating a first plane vector according to respective projection coordinates of the two preset calibration points in the first coordinate system; calculating a second plane vector according to the first gravity vector; the first plane equation is calculated from the first plane vector and the second plane vector.
Optionally, the angle calculation module 72 is further configured to:
determining a first normal vector of the first plane equation; determining a second normal vector of the second plane equation; calculating a vector included angle between the first normal vector and the second normal vector; and determining the vector included angle as the plane inclined angle.
Optionally, the trapezoidal correction module 74 is further configured to:
calculating the current posture of the projector according to the calibration posture and the posture inclination angle of the projector; calculating vertex coordinates of a projection area according to the current projection gesture and the projection ratio; and carrying out trapezoidal correction according to the vertex coordinates.
It should be noted that, because the content of information interaction and execution process between the above devices/units is based on the same concept as the method embodiment of the present application, specific functions and technical effects thereof may be referred to in the method embodiment section, and will not be described herein.
In addition, the trapezoidal correction device shown in fig. 7 may be a software unit, a hardware unit, or a unit combining soft and hard, which are built in an existing terminal device, or may be integrated into the terminal device as an independent pendant, or may exist as an independent terminal device.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, the specific names of the functional units and modules are only for distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.
Fig. 8 is a schematic structural diagram of a projector according to an embodiment of the present application. As shown in fig. 8, the projector 8 of this embodiment includes: at least one processor 80 (only one shown in fig. 8), a memory 81, and a computer program 82 stored in the memory 81 and executable on the at least one processor 80, the processor 80 implementing the steps in any of the various trapezoidal correction method embodiments described above when executing the computer program 82.
The projector in the embodiment of the application is equipment capable of projecting an input image onto a curtain after signal processing. The projector may be a separate projection device or may be a device with a projection function mounted on another terminal. The projector may include, but is not limited to, a processor, a memory. It will be appreciated by those skilled in the art that fig. 8 is merely an example of projector 8 and is not intended to be limiting of projector 8, and may include more or fewer components than shown, or may combine certain components, or may include different components, such as input-output devices, network access devices, etc. The projector may be connected to different input sources such as a computer, a gaming machine, a U disk, etc.
The processor 80 may be a central processing unit (Central Processing Unit, CPU), the processor 80 may also be other general purpose processors, digital signal processors (Digital SignalProcessor, DSP), application specific integrated circuits (Appl ication Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 81 may in some embodiments be an internal storage unit of the projector 8, such as a hard disk or a memory of the projector 8. The memory 81 may in other embodiments also be an external storage device of the projector 8, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash Card (Flash Card) or the like, which are provided on the projector 8. Further, the memory 81 may also include both an internal storage unit and an external storage device of the projector 8. The memory 81 is used for storing an operating system, application programs, boot Loader (Boot Loader), data, other programs, etc., such as program codes of the computer program. The memory 81 may also be used to temporarily store data that has been output or is to be output.
Embodiments of the present application also provide a computer readable storage medium storing a computer program which, when executed by a processor, implements steps for implementing the various method embodiments described above.
Embodiments of the present application provide a computer program product enabling a terminal device to carry out the steps of the method embodiments described above when the computer program product is run on the terminal device.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present application may implement all or part of the flow of the method of the above embodiments, and may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each of the method embodiments described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include at least: any entity or device capable of carrying computer program code to the device/projector, recording medium, computer Memory, read-Only Memory (ROM), random access Memory (RAM, random Access Memory), electrical carrier signals, telecommunications signals, and software distribution media. Such as a U-disk, removable hard disk, magnetic or optical disk, etc. In some jurisdictions, computer readable media may not be electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided by the present application, it should be understood that the disclosed apparatus/projector and method may be implemented in other manners. For example, the apparatus/projector embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical functional division, and there may be additional divisions in actual implementation, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (10)
1. A trapezoidal correction method, characterized by being applied to a projector including an inertial sensor, comprising:
obtaining calibration parameters calibrated in advance, wherein the calibration parameters comprise the calibration gesture of the projector;
when the change of the posture of the projector is detected through the inertial sensor, calculating a plane inclination angle between a first projection plane and a second projection plane, wherein the first projection plane is a projection plane after the change of the posture of the projector, and the second projection plane is a projection plane before the change of the posture of the projector;
determining an attitude inclination angle of the projector according to the plane inclination angle;
and carrying out trapezoidal correction according to the calibration posture and the posture inclination angle of the projector.
2. The trapezoidal correction method according to claim 1, wherein said calculating a plane inclination angle between the first projection plane and the second projection plane includes:
calculating a first plane equation of the first projection plane;
acquiring a second plane equation of the second projection plane;
the plane tilt angle is calculated from the first plane equation and the second plane equation.
3. The trapezoidal correction method according to claim 2, wherein the projector further comprises a ranging sensor, and the pre-calibrated calibration parameters include a light emitting direction vector of the ranging sensor under a first coordinate system, where the first coordinate system is the coordinate system where the projector is located;
the calculating a first plane equation for the first projection plane includes:
acquiring a first gravity vector in the first coordinate system;
obtaining distance measurement distances between two preset calibration points on the first projection plane and the projector respectively through the distance measurement sensor, wherein the preset calibration points are determined by the light emitting direction vector;
calculating respective projection coordinates of the two preset calibration points in the first coordinate system according to the light-emitting direction vector and the distance measurement distance;
and calculating the first plane equation according to the first gravity vector and the respective projection coordinates of the two preset calibration points in the first coordinate system.
4. A trapezoidal correction method as set forth in claim 3, wherein said pre-calibrated calibration parameters include a transformation matrix between a world coordinate system and said first coordinate system;
the acquiring a first gravity vector in the first coordinate system includes:
acquiring a second gravity vector in the world coordinate system through the inertial sensor;
and converting the second gravity vector into a first gravity vector in the first coordinate system according to the transformation matrix.
5. The trapezoidal correction method according to claim 3, wherein said calculating said first plane equation from respective projection coordinates of said first gravity vector and said two preset calibration points in said first coordinate system includes:
calculating a first plane vector according to respective projection coordinates of the two preset calibration points in the first coordinate system;
calculating a second plane vector according to the first gravity vector;
the first plane equation is calculated from the first plane vector and the second plane vector.
6. The trapezoidal correction method according to claim 2, wherein said calculating the plane inclination angle from the first plane equation and the second plane equation includes:
determining a first normal vector of the first plane equation;
determining a second normal vector of the second plane equation;
calculating a vector included angle between the first normal vector and the second normal vector;
and determining the vector included angle as the plane inclined angle.
7. The trapezoidal correction method according to claim 1, wherein said trapezoidal correction according to said calibration attitude and said attitude inclination angle of said projector includes:
calculating the current posture of the projector according to the calibration posture and the posture inclination angle of the projector;
calculating vertex coordinates of a projection area according to the current projection gesture and the projection ratio;
and carrying out trapezoidal correction according to the vertex coordinates.
8. A trapezoidal correction device, characterized by being applied to a projector including an inertial sensor, the device comprising:
the parameter acquisition module is used for acquiring calibration parameters calibrated in advance, wherein the calibration parameters comprise the calibration gesture of the projector;
the angle calculation module is used for calculating a plane inclination angle between a first projection plane and a second projection plane when the change of the posture of the projector is detected through the inertial sensor, wherein the first projection plane is a projection plane after the change of the posture of the projector, and the second projection plane is a projection plane before the change of the posture of the projector;
an angle determining module for determining an attitude inclination angle of the projector according to the plane inclination angle;
and the trapezoid correction module is used for performing trapezoid correction according to the calibration posture and the posture inclination angle of the projector.
9. A projector comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the method of any one of claims 1 to 7 when executing the computer program.
10. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the method according to any one of claims 1 to 7.
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| CN114760454A (en) * | 2022-05-24 | 2022-07-15 | 海信视像科技股份有限公司 | Projection equipment and trigger correction method |
| CN114745529A (en) * | 2022-03-30 | 2022-07-12 | 深圳市橙子数字科技有限公司 | Projector single TOF trapezoidal correction method and projector |
| CN117288151B (en) * | 2023-11-21 | 2024-02-13 | 深圳市橙子数字科技有限公司 | Three-dimensional attitude determination method and device of projection equipment and electronic equipment |
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