WO2019161570A1

WO2019161570A1 - Projector and temperature compensation method for trapezoidal correction thereof

Info

Publication number: WO2019161570A1
Application number: PCT/CN2018/077278
Authority: WO
Inventors: 那庆林; 麦浩晃; 黄彦
Original assignee: 神画科技（深圳）有限公司
Priority date: 2018-02-26
Filing date: 2018-02-26
Publication date: 2019-08-29

Abstract

A projector and a temperature compensation method for trapezoidal correction thereof. The method comprises the steps of: triggering the trapezoidal correction of a projector (S111); obtaining the temperature of a projection lens (S112); compensating the preset parameter of a projection unit according to the temperature of the projection lens (S113); and obtaining a trapezoidal correction parameter according to the compensated preset parameter and the calibration information of a projection image, completing automatic trapezoidal correction according to the trapezoidal correction parameter, and projecting a corrected rectangular image on a projection display surface (S114). By obtaining the temperature of the projection lens, the preset parameter of the projection unit is compensated during the trapezoidal correction, so as to eliminate a projection error, obtain a real-time correction parameter, complete the trapezoidal correction of the projected image, and improve the precision of the trapezoidal correction.

Description

Projector and temperature compensation method for trapezoidal correction thereof

Technical field

The invention relates to the field of projectors, and in particular to a projector and a temperature compensation method for trapezoidal correction.

Background technique

Due to the thermal effect of the projection lens material, when the temperature changes, the refractive index and expansion coefficient of the lens change, which causes the projection parameters to change. The projection distance does not change. When the temperature rises, the projection unit projection screen becomes smaller; when the temperature drops, the projection unit projection screen becomes larger.

In particular, in the trapezoidal correction process based on the principle of triangulation, the change of the projection picture causes the position of the calibration point to change, and the calculation error of the deflection angle is enlarged, which greatly affects the effect of the trapezoidal correction. Therefore, the temperature change seriously affects the accuracy of the projector's trapezoidal correction.

Specifically, and referring to FIG. 1, FIG. 1 is a schematic diagram of the trapezoidal correction precision of the projector's thermal defocusing effect; in the front projection state, the projection unit deflection angle is 0, and in the left and right trapezoidal correction process, P1 and P2 are the targets projected on the screen. At a fixed point, after the temperature rises, the projection ratio becomes larger, the image on the screen shrinks, P1 and P2 become P'1, P'2, and the projection boundary lines PP1, PP2 become PP'1, PP'2, and the dotted line in the figure The monitoring unit captures the calibration points P1 and P2 and moves to the center of the image. If the value of the projection ratio is not changed, the trapezoidal correction unit mistakenly assumes that the calibration point is at the Q1 and Q2 positions, and calculates the screen deflection angle by using the information of the points Q1 and Q2; As can be seen, the projection plane P1P2 deflects the angle θ to the projection plane Q1Q2, so that the trapezoidal correction produces an error of the θ angle.

technical problem

The technical problem to be solved by the present invention is to provide a projector and a temperature compensation method for trapezoidal correction according to the above-mentioned defects of the prior art, which solves the problem that the projection screen changes due to the lens temperature change, thereby causing inaccurate trapezoidal correction.

The technical problem to be solved by the present invention is to provide a projector for solving the above-mentioned defects of the prior art, which solves the problem that the projection screen changes due to the lens temperature change, thereby causing the trapezoidal correction to be inaccurate.

Technical solution

The technical solution adopted by the present invention to solve the technical problem thereof is to provide a temperature compensation method for trapezoidal correction of a projector, the projector comprising a projection unit, the projection unit comprising a projection lens, comprising the steps of: triggering trapezoidal correction of the projector; The temperature of the projection lens; the preset parameters of the projection unit are compensated according to the temperature of the projection lens; the trapezoidal correction parameters are obtained according to the compensated preset parameters and the calibration information of the projection screen, and the automatic trapezoid correction is completed according to the trapezoidal correction parameters, and the projection is performed. The corrected rectangular image is projected on the display surface.

Preferably, the preset parameter is a projection ratio of the projection unit; and the temperature compensation method further comprises the steps of: constructing a temperature-projection ratio curve, wherein the temperature-projection ratio curve includes the temperature of each projection lens. Corresponding projection ratio; according to the temperature and temperature-projection ratio curve of the projection lens, the projection ratio of the projection unit at this time is corrected to the projection ratio corresponding to the temperature-projection ratio curve.

Preferably, the preset parameter is a pixel position of the projection unit; and the temperature compensation method further comprises the steps of: constructing a temperature-pixel position offset coefficient curve, wherein the temperature-pixel position offset coefficient curve Include a pixel position offset coefficient corresponding to the temperature of each projection lens; according to the temperature and temperature of the projection lens - the pixel position offset coefficient curve, obtain the pixel position offset coefficient corresponding to the temperature at this time, and according to the pixel The point position offset coefficient corrects the pixel position at this time.

Preferably, the temperature compensation method further comprises the steps of: acquiring a temperature of the aspherical lens in the projection lens and using the temperature of the projection lens.

Preferably, the step of obtaining the temperature of the aspherical lens in the projection lens comprises:

Obtaining the temperature near the aspherical lens; obtaining an error ratio of the self-temperature of the corresponding aspherical lens and its accessory temperature according to the type of the aspherical lens, and obtaining the self-temperature of the aspherical lens according to the error ratio and the temperature of the vicinity of the aspherical lens.

Preferably, the preset parameter is an angle of view of a calibration point of the projection unit.

The technical solution adopted by the present invention to solve the technical problem thereof is to provide a projector including a projection unit and a monitoring unit, the projection unit including a projection lens, wherein the projector further includes a main control unit and a temperature sensor disposed on the projection lens, the temperature sensor is connected to the main control unit, and acquires temperature information of the projection lens and sent to the main control unit; the main control unit includes a temperature compensation module connected to the projection unit, The main control unit controls the temperature compensation module to compensate the preset parameters of the projection unit according to the temperature information when triggering the trapezoidal correction, and obtains the trapezoidal correction parameter according to the compensated preset parameters and the calibration information of the projection screen obtained by the monitoring unit. And controlling the projection unit according to the trapezoidal correction parameter to complete the automatic trapezoidal correction, and projecting the corrected rectangular image on the projection display surface.

Preferably, the projection lens comprises an aspherical lens, and the temperature sensor is disposed adjacent to the aspherical lens.

Preferably, the projection lens comprises a lens barrel, the aspherical lens is disposed in the lens barrel, and the temperature sensor is disposed on the lens barrel.

Preferably, the projection lens comprises a lens barrel, the aspherical lens is disposed in the lens barrel, a through hole is disposed on the lens barrel, and the temperature sensor is disposed in the through hole.

Beneficial effect

The invention has the beneficial effects that compared with the prior art, the invention acquires the temperature of the projection lens by designing a projector and its trapezoidal correction temperature compensation method, thereby compensating the preset parameters of the projection unit during the trapezoidal correction. The projection error is eliminated, the correct correction parameters of the real-time trapezoid are obtained, the trapezoidal correction of the projected image is completed, and the precision of the trapezoidal correction is improved.

DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a schematic diagram showing the accuracy of trapezoidal correction caused by the thermal defocus of the existing projector;

2 is a schematic flow chart of a temperature compensation method of the present invention;

3 is a schematic flow chart of a second embodiment of the temperature compensation method of FIG. 2;

4 is a schematic flow chart of a third embodiment of the temperature compensation method of FIG. 2;

5 is a schematic flow chart of a temperature compensation method based on a projection ratio according to the present invention;

6 is a schematic flow chart of a second embodiment of the temperature compensation method of FIG. 5;

7 is a schematic flow chart of a third embodiment of the temperature compensation method of FIG. 5;

8 is a schematic flow chart of a temperature compensation method based on pixel position of the present invention;

9 is a schematic flow chart of a second embodiment of the temperature compensation method of FIG. 8;

10 is a schematic flow chart of a third embodiment of the temperature compensation method of FIG. 8;

Figure 11 is a schematic view showing the structure of a projector of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

As shown in Figures 2 to 4, the present invention provides a preferred embodiment of a temperature compensation method for projector trapezoidal correction.

A temperature compensation method for projector trapezoidal correction, the projector comprises a projection unit, and the projection unit comprises a projection lens, comprising the steps of:

Step S111, triggering a trapezoidal correction of the projector;

Step S112, obtaining a temperature of the projection lens;

Step S113: Compensating preset parameters of the projection unit according to the temperature of the projection lens;

Step S114: Acquire a trapezoidal correction parameter according to the compensated preset parameter and the calibration information of the projection screen, and complete the automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

Of course, the order of the steps is not unique, and the temperature of the projection lens can be continuously obtained, and then the trapezoidal correction of the projector can be triggered.

In this embodiment, in step S11, the projector's own state is acquired by the motion sensor or the angle sensor of the projector, and the trapezoidal correction of the projector is triggered when the projector performs horizontal rotation and vertical rotation; wherein the motion sensor includes movement Sensor, gyroscope or 3D sensor. And, in step S12, the temperature of the aspherical lens in the projection lens is acquired as the temperature of the projection lens.

In this embodiment, there are three preferred solutions for obtaining the temperature of the projection lens.

Solution 1: The temperature is obtained in real time. When the trapezoidal correction of the projector is triggered, the currently obtained real-time temperature is used as the reference temperature for compensation calculation. Specifically include the steps:

Step S121, obtaining the temperature of the projection lens in real time;

Step S122, triggering a trapezoidal correction of the projector;

Step S123: Compensating preset parameters of the projection unit according to the temperature of the projection lens;

Step S124: Acquire a trapezoidal correction parameter according to the compensated preset parameter and the calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

The above steps 121 and 122 are not in the order of order, only to facilitate the distinction of the step contents.

Solution 2, waiting for triggering the trapezoidal correction of the projector, and obtaining the temperature of the current projection lens during the trapezoidal correction, and serving as the reference temperature for compensating the calculation; for details, refer to the above steps S111 to S114.

Solution 3: Regularly obtain the temperature of the current projection lens, and then trigger the trapezoidal correction, and take the temperature of the obtained projection lens as the reference temperature during the compensation calculation. Specifically include the steps:

Step S131, timingly acquiring the temperature of the projection lens;

Step S132, triggering a trapezoidal correction of the projector;

Step S133: Compensating preset parameters of the projection unit according to the temperature of the projection lens;

Step S134: Acquire a trapezoidal correction parameter according to the compensated preset parameter and the calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

In this embodiment, the step of acquiring the temperature of the aspherical lens in the projection lens comprises: acquiring a temperature in the vicinity of the aspherical lens; and obtaining an error ratio of the temperature of the corresponding aspherical lens and the temperature of the accessory according to the type of the aspherical lens; And obtaining the self-temperature of the aspherical lens according to the error ratio and the temperature near the aspherical lens.

The most accurate position is the temperature of the aspherical lens, but this point cannot be measured. Only the temperature near it can be measured. In order to be suitable for mass production, the lens design usually places the aspherical lens on both ends of the lens, that is, the front end or the rear. At the end, it is also possible to find a position near the lens. The temperature change at this point corresponds to the temperature change of the aspherical lens, so that the temperature of the aspherical lens can be calculated according to the corresponding relationship.

As shown in FIGS. 5 to 7, the present invention provides a preferred embodiment of a temperature compensation method based on a throw ratio.

The preset parameter is a projection ratio of the projection unit; the temperature compensation method further includes the steps of:

Step S211, constructing a temperature-projection ratio curve, wherein the temperature-projection ratio curve includes a projection ratio corresponding to the temperature of each projection lens;

Step S212, triggering a trapezoidal correction of the projector;

Step S213, acquiring a temperature of the projection lens;

Step S214, according to the temperature of the projection lens and the temperature-projection ratio curve, correct the projection ratio of the projection unit at this time to the projection ratio corresponding to the temperature-projection ratio curve;

Step S215: Acquire a trapezoidal correction parameter according to the compensated projection ratio and calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

In the same way, the order of the steps is not unique, and the steps can be adjusted accordingly according to the actual situation.

In this embodiment, the temperature-projection ratio curve indicates that each type of projection lens generates different projection ratios in each temperature environment, and can obtain a corresponding graph according to the above characteristics, thereby The projection ratio is corrected to improve the accuracy of the trapezoidal correction.

Wherein, the projection ratio indicates that the projection ratio is the ratio of the projection distance to the width of the screen.

Step S221, constructing a temperature-projection ratio curve;

Step S222: acquiring the temperature of the projection lens in real time;

Step S223, triggering trapezoidal correction of the projector;

Step S224, according to the temperature of the projection lens and the temperature-projection ratio curve, the projection ratio of the projection unit at this time is corrected to a projection ratio corresponding to the temperature-projection ratio curve;

Step S225, acquiring a trapezoidal correction parameter according to the compensated projection ratio and the calibration information of the projection screen, and completing the automatic trapezoidal correction according to the trapezoidal correction parameter, and projecting the corrected rectangular image on the projection display surface.

The above steps 222 and 223 are not in the order of order, only to facilitate the distinction of the step contents.

Solution 2, waiting for triggering the trapezoidal correction of the projector, and obtaining the temperature of the current projection lens during the trapezoidal correction, and serving as the reference temperature for compensating the calculation; for details, refer to the above steps S211 to S215.

Step S231, constructing a temperature-projection ratio curve, wherein the temperature-projection ratio curve includes a projection ratio corresponding to the temperature of each projection lens;

Step S232, timingly acquiring the temperature of the projection lens;

Step S233, triggering a trapezoidal correction of the projector;

Step S234, according to the temperature and temperature-projection ratio curve of the projection lens, correct the projection ratio of the projection unit at this time to the projection ratio corresponding to the temperature-projection ratio curve;

Step S235: Acquire a trapezoidal correction parameter according to the compensated projection ratio and the calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

As shown in FIGS. 8 to 10, the present invention provides a preferred embodiment of a temperature compensation method based on pixel position.

The preset parameter is a pixel point position of the projection unit; the temperature compensation method further includes the steps of:

Step S311, constructing a temperature-pixel point position shift coefficient curve, wherein the temperature-pixel point position shift coefficient curve includes a pixel point position offset coefficient corresponding to the temperature of each projection lens;

Step S312, triggering trapezoidal correction of the projector;

Step S313, obtaining a temperature of the projection lens;

Step S314, according to the temperature and temperature of the projection lens-pixel position offset coefficient curve, obtain the pixel position offset coefficient corresponding to the temperature at this time, and correct the pixel position at this time according to the pixel position offset coefficient;

Step S315: Acquire a trapezoidal correction parameter according to the compensated pixel position and the calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

In this embodiment, the temperature-pixel point position shift coefficient curve is used to obtain the change coefficient of the actual pixel point position and the preset pixel point position at different temperatures, and the current prime point position is obtained by the coefficient of variation, thereby The position of the prime point is corrected to improve the accuracy of the trapezoidal correction.

Step S321, constructing a temperature-pixel point position shift coefficient curve, wherein the temperature-pixel point position shift coefficient curve includes a pixel point position offset coefficient corresponding to the temperature of each projection lens;

Step S322: acquiring the temperature of the projection lens in real time;

Step S323, triggering trapezoidal correction of the projector;

Step S324, according to the temperature and temperature of the projection lens-pixel position offset coefficient curve, obtain the pixel position offset coefficient corresponding to the temperature at this time, and correct the pixel position at this time according to the pixel position offset coefficient;

Step S325: Acquire a trapezoidal correction parameter according to the compensated pixel position and the calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

The above steps 322 and 323 are not in the order of order, only to facilitate the distinction of the step content.

Solution 2, waiting for triggering the trapezoidal correction of the projector, and obtaining the temperature of the current projection lens during the trapezoidal correction, and serving as the reference temperature for compensating the calculation; for details, refer to the above steps S311 to S315.

Step S331, constructing a temperature-pixel point position shift coefficient curve, wherein the temperature-pixel point position shift coefficient curve includes a pixel point position offset coefficient corresponding to the temperature of each projection lens;

Step S332, timingly acquiring the temperature of the projection lens;

Step S333, triggering trapezoidal correction of the projector;

Step S334, according to the temperature and temperature of the projection lens-pixel position offset coefficient curve, obtain the pixel position offset coefficient corresponding to the temperature at this time, and correct the pixel position at this time according to the pixel position offset coefficient;

Step S335: Acquire a trapezoidal correction parameter according to the compensated pixel position and the calibration information of the projection screen, and complete automatic trapezoidal correction according to the trapezoidal correction parameter, and project the corrected rectangular image on the projection display surface.

In the present invention, a preferred embodiment of a temperature compensation method is also provided.

The preset parameter is an angle of view of a calibration point of the projection unit.

Among them, the field of view is also called the field of view in optical engineering, and the size of the field of view determines the field of view of the optical instrument. The field of view can be expressed in terms of FOV, and its relationship with the focal length is as follows: h = f*tan\[Theta]; image height = EFL*tan (semi-FOV); EFL is the focal length; FOV is the field of view.

As shown in Figure 5, the present invention provides a preferred embodiment of a projector.

A projector comprising a projection unit 12 and a monitoring unit 13, the projection unit 12 comprising a projection lens 121, wherein the projector further comprises a main control unit 11 and a temperature sensor disposed on the projection lens 121 The temperature sensor 14 is connected to the main control unit 11 and acquires the temperature information of the projection lens 121 and sent to the main control unit 11; the main control unit 11 includes a temperature compensation module 111 connected to the projection unit 12, The main control unit 11 controls the temperature compensation module 111 to compensate the preset parameters of the projection unit 12 according to the temperature information when triggering the trapezoidal correction, and according to the compensated preset parameters and the calibration information of the projection screen obtained by the monitoring unit 13. Obtaining the trapezoidal correction parameter, and controlling the projection unit 12 to complete the automatic trapezoidal correction according to the trapezoidal correction parameter, and projecting the corrected rectangular image on the projection display surface.

Specifically, the main control unit 11 further includes a correction module, and the projection unit 12 is controlled by the correction module to implement the trapezoidal correction, and the temperature compensation module 111 compensates the relevant parameters.

In the present embodiment, the projection lens 121 includes an aspherical lens, and the temperature sensor 14 is disposed adjacent to the aspherical lens. Among them, the surface curvature of the aspherical lens is different from that of the ordinary spherical lens. In order to pursue the thinness of the lens, it is necessary to change the curved surface of the lens. In the past, the spherical design was used to increase the aberration and deformation, and the apparent image was unclear, and the visual field was distorted. Bad phenomena such as narrow vision. Now the aspherical design corrects the image and solves problems such as distortion of the horizon.

The projection unit 12 includes an imaging chip, and projects an image onto the projection image through the projection lens 121 to realize projection magnification.

Further, the projection lens 121 includes a lens barrel, the aspherical lens is disposed in the lens barrel, and the temperature sensor 14 is disposed on the lens barrel.

Alternatively, the projection lens 121 includes a lens barrel, the aspherical lens is disposed in the lens barrel, a through hole is disposed on the lens barrel, and the temperature sensor 14 is disposed in the through hole.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and equivalent changes or modifications made by the scope of the present invention are covered by the present invention.

Claims

A temperature compensation method for trapezoidal correction of a projector, the projector comprising a projection unit, the projection unit comprising a projection lens, comprising:

Triggering the trapezoidal correction of the projector;

Obtaining the temperature of the projection lens;

Compensating the preset parameters of the projection unit according to the temperature of the projection lens;

The trapezoidal correction parameter is obtained according to the preset parameters after compensation and the calibration information of the projection screen, and the automatic trapezoidal correction is completed according to the trapezoidal correction parameter, and the corrected rectangular image is projected on the projection display surface.
The temperature compensation method according to claim 1, wherein the preset parameter is a projection ratio of the projection unit; and the temperature compensation method further comprises the steps of:

Constructing a temperature-to-projection ratio curve, wherein the temperature-projection ratio curve includes a projection ratio corresponding to a temperature of each projection lens;

According to the temperature and temperature-projection ratio curve of the projection lens, the projection ratio of the projection unit at this time is corrected to the projection ratio corresponding to the temperature-projection ratio curve.
The temperature compensation method according to claim 1, wherein the preset parameter is a pixel point position of the projection unit; and the temperature compensation method further comprises the steps of:

Constructing a temperature-pixel point position shift coefficient curve, wherein the temperature-pixel point position shift coefficient curve includes a pixel point position shift coefficient corresponding to the temperature of each projection lens;

According to the temperature and temperature of the projection lens-pixel position offset coefficient curve, the pixel position offset coefficient corresponding to the temperature at this time is obtained, and the pixel position at this time is corrected according to the pixel position offset coefficient.
The temperature compensation method according to claim 2 or 3, wherein the temperature compensation method further comprises the steps of:

Obtain the temperature of the aspherical lens in the projection lens and use it as the temperature of the projection lens.
The temperature compensation method according to claim 4, wherein the step of acquiring the temperature of the aspherical lens in the projection lens comprises:

Obtaining the temperature near the aspherical lens;

The error ratio of the self-temperature of the corresponding aspherical lens to the temperature of the accessory is obtained according to the type of the aspherical lens, and the temperature of the aspherical lens is obtained according to the error ratio and the temperature of the vicinity of the aspherical lens.
The temperature compensation method according to claim 1, wherein the preset parameter is an angle of view of a calibration point of the projection unit.
A projector comprising a projection unit and a monitoring unit, the projection unit comprising a projection lens, wherein the projector further comprises a main control unit and a temperature sensor disposed on the projection lens, the temperature sensor and The main control unit is connected, and obtains temperature information of the projection lens and sends it to the main control unit; the main control unit includes a temperature compensation module connected to the projection unit, and the main control unit controls the temperature information according to the temperature information when triggering the trapezoidal correction The temperature compensation module compensates the preset parameters of the projection unit, and obtains the trapezoidal correction parameters according to the compensated preset parameters and the calibration information of the projection screen obtained by the monitoring unit, and controls the projection unit to complete the automatic trapezoidal correction according to the trapezoidal correction parameters. A corrected rectangular image is projected on the projection display surface.
The projector according to claim 7, wherein said projection lens comprises an aspherical lens, and said temperature sensor is disposed adjacent to the aspherical lens.
The projector according to claim 8, wherein said projection lens comprises a lens barrel, said aspherical lens is disposed in said lens barrel, and said temperature sensor is disposed on said lens barrel.
The projector according to claim 8, wherein the projection lens comprises a lens barrel, the aspherical lens is disposed in the lens barrel, a through hole is disposed on the lens barrel, and the temperature sensor is disposed in the through hole Inside.