Laser projection equipment and galvanometer calibration method

Abstract

The embodiment of the invention provides laser projection equipment and a galvanometer calibration method, and relates to the technical field of laser projection. The laser projection apparatus includes: a lens assembly configured to project an optical signal; the display screen is configured to present the projected image; a detector configured to collect the projected image; the processor is configured to split the galvanometer calibration image into a first sub-image and a second sub-image; in the first sub-frame, moving a galvanometer in the lens assembly to a first position, and projecting a first sub-image at a first display position of the display screen through the lens assembly; in the second sub-frame, moving a galvanometer in the lens assembly to a second position, and projecting a second sub-image at a second display position of the display screen through the lens assembly; and calibrating the first position and the second position of the galvanometer according to the offset between the first sub-image and the second sub-image collected by the detector. The embodiment of the invention is used for solving the problem that the calibration precision of the laser projection equipment on the galvanometer is relatively low.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of laser projection technology, and more specifically, to a laser projection device and a galvanometer calibration method. Background Art

[0002] Laser projection equipment is a display technology that uses solid-state lasers of red, green and blue (R, G, B) as light sources. It has the advantages of low power consumption and longer service life. The service life of laser projection equipment is almost 10 times that of traditional light bulbs. Laser projection equipment can truly reproduce the rich and bright colors of the objective world and provide excellent expression. The color gamut coverage of laser display can reach more than 90% of the color space that the human eye can recognize, which is more than twice the color gamut coverage of traditional display technology, breaking through the shortcomings of the color gamut space of the first three generations of display technology.

[0003] Resolution is also an important indicator of the performance of laser projection equipment. The higher the resolution, the higher the precision of the image that can be projected onto the screen, the more information is displayed, and the clearer the picture is. However, the resolution of laser projection equipment is limited by hardware technology, and it is difficult to improve the resolution. At present, many laser projection devices use digital micromirror devices (DMD) as key components, and the resolution of laser projection equipment is mainly determined by the resolution of DMD. With the help of micro-oscillating reflector (referred to as galvanometer) technology, low-resolution DMD can be used to project high-resolution images. By dividing a high-resolution frame image into two low-resolution sub-images, and then controlling the galvanometer in the DMD to flip repeatedly, the two sub-images are sequentially displaced in one image display cycle, so as to achieve high-resolution image projection. The key is that the relative position of the two sub-images must be accurate, which requires accurate calibration of the amplitude and angle of the galvanometer flip, but the current laser projection equipment has low calibration accuracy for the galvanometer. Summary of the invention

[0004] The exemplary embodiments of the present application provide a laser projection device and a galvanometer calibration method, which are used to solve the problem of low calibration accuracy of the galvanometer in the laser projection device.

[0005] The technical solutions provided by the embodiments of this application are as follows:

[0006] In a first aspect, an embodiment of the present application provides a laser projection device, comprising:

[0007] a lens assembly configured to project the optical signal;

[0008] a display screen configured to present a projected image;

[0009] a detector configured to collect the projected image;

[0010] A processor configured to split the galvanometer calibration image into a first sub-image and a second sub-image;

[0011] In a first subframe, the galvanometer in the lens assembly is moved to a first position, and the first sub-image is projected at a first display position on the display screen through the lens assembly;

[0012] In a second subframe, the galvanometer in the lens assembly is moved to a second position, and the second sub-image is projected at a second display position on the display screen through the lens assembly;

[0013] The first position and the second position of the galvanometer are calibrated according to the offset between the first sub-image and the second sub-image collected by the detector.

[0014] In a second aspect, an embodiment of the present application provides a galvanometer calibration method, which is applied to a laser projection device, and the method includes:

[0015] Splitting the galvanometer calibration image into a first sub-image and a second sub-image;

[0016] In a first subframe, a galvanometer in the lens assembly is moved to a first position, and the first sub-image is projected at a first display position of a display screen through the lens assembly;

[0017] In a second subframe, the galvanometer in the lens assembly is moved to a second position, and the second sub-image is projected at a second display position on the display screen through the lens assembly;

[0018] The first position and the second position of the galvanometer are calibrated according to the offset between the first sub-image and the second sub-image collected by the detector.

[0019] In a third aspect, an embodiment of the present application provides an electronic device, comprising: a memory and a processor, wherein the memory is used to store a computer program; and the processor is used to enable the electronic device to implement the galvanometer calibration method described in the second aspect or any embodiment of the second aspect when executing the computer program.

[0020] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a computing device, the computing device implements the galvanometer calibration method described in the second aspect or any embodiment of the second aspect.

[0021] In a fifth aspect, an embodiment of the present application provides a computer program product. When the computer program product runs on a computer, the computer implements the galvanometer calibration method described in the second aspect or any embodiment of the second aspect.

[0022] It can be seen from the above technical solutions that the laser projection device and the galvanometer calibration method provided in the embodiment of the present application, through the processor, split the galvanometer calibration image into a first sub-image and a second sub-image, and project and display them in the first sub-frame and the second sub-frame respectively. And control the galvanometer in the lens assembly to flip, move the galvanometer to the first position in the first sub-frame, so as to project the first sub-image at the first display position of the display screen; move the galvanometer to the second position in the second sub-frame, so as to project the second sub-image at the second display position of the display screen. Then, according to the offset between the first sub-image and the second sub-image collected by the detector, the first position and the second position of the galvanometer are calibrated, wherein the galvanometer calibration pattern used has significant color characteristics, and the split first sub-image and the second sub-image also have color characteristics and differences respectively, so it is possible to accurately judge whether the offset between the first sub-image and the second sub-image is consistent with the preset, thereby solving the problem of low calibration accuracy of the galvanometer of the laser projection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the implementation methods in the embodiments of the present application or the related technologies, the following is a brief introduction to the drawings required for use in the embodiments or the related technology descriptions. Obviously, the drawings described below are some embodiments of the present application, and a person skilled in the art can also obtain other drawings based on these drawings.

[0024] Figure 1 A schematic diagram showing the structure of a laser projection device in some embodiments is shown;

[0025] Figure 2 A schematic diagram of the structure of another laser projection device in some embodiments is shown;

[0026] Figure 3 A schematic structural diagram of another laser projection device in some embodiments is shown;

[0027] Figure 4 A diagram showing the position of a first sub-image when the galvanometer mirror is deflected in some embodiments;

[0028] Figure 5 A diagram showing the position of the second sub-image when the galvanometer mirror is deflected in some embodiments;

[0029] Figure 6 A schematic diagram showing a galvanometer calibration image in some embodiments;

[0030] Figure 7 A schematic diagram showing a first sub-image in some embodiments;

[0031] Figure 8 A schematic diagram showing a second sub-image in some embodiments;

[0032] Fig. 9 A schematic diagram showing a projection image with a correct galvanometer phase in some embodiments;

[0033] Fig.10 A schematic diagram showing another projection image with correct galvanometer phase in some embodiments;

[0034] Fig.11 A schematic diagram showing a projected image with a galvanometer phase error in some embodiments;

[0035] Fig.12 A schematic diagram showing a projection image of another galvanometer phase error in some embodiments;

[0036] Fig.13 A schematic diagram showing a galvanometer rotation axis in some embodiments;

[0037] Fig.14 A schematic diagram showing a back-projected galvanometer calibration image in some embodiments;

[0038] Fig.15 A schematic diagram showing a first sub-image of a back-projection in some embodiments;

[0039] Fig.16 A schematic diagram showing a back-projected second sub-image in some embodiments;

[0040] Fig.17 A schematic diagram showing a projection image of a reversely projected galvanometer mirror with correct phase in some embodiments is shown;

[0041] Fig.18 A schematic diagram showing a projection image of another galvanometer mirror with correct phase in reverse projection in some embodiments;

[0042] Fig.19 A schematic diagram showing a projection image of a reversely projected galvanometer mirror phase error in some embodiments;

[0043] Fig. 20 A schematic diagram showing a projection image of another galvanometer phase error in reverse projection in some embodiments;

[0044] Fig.21 A flow chart of a galvanometer calibration method in some embodiments is shown. DETAILED DESCRIPTION

[0045] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0046] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0047] The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0048] Figure 1 is a schematic diagram of the structure of a laser projection device provided in an embodiment of the present application, Figure 2 is a schematic diagram of the structure of another laser projection device provided in an embodiment of the present application, Figure 3 Schematic diagram of the structure of the lens assembly of the laser projection device provided in the embodiment of the present application. Figure 1 , Figure 2 and Figure 3 As shown, the projection device may include a processor 10, at least one laser driving component 20, a light source 30, a light valve 40, a galvanometer driving component 50, a galvanometer 60, a display screen 130, and a detector 101. The light source 30 may include at least one group of lasers corresponding to the at least one laser driving component 20. The at least one refers to one or more, and the multiple refers to two or more. The at least one group refers to one or more groups, and the multiple groups refer to two or more groups, and each group of lasers may include one or more lasers.

[0049] The processor 10 may be a digital light processing (DLP) chip. The light source 30 may be a laser light source, for example, Figure 1, the laser light source may include a blue laser 301, a red laser 302 and a green laser 303. The light valve 40 may be a digital micromirror device (DMD). The galvanometer 60 may be used to shift sub-images of different frames to different positions of the projection screen, thereby realizing the superposition display of the multiple frames of sub-images, thereby achieving the effect of expanding the resolution of the projection device. In the embodiment of the present application, the galvanometer 60 has two deflection positions, that is, the galvanometer 60 can shift the sub-image to two different display positions of the projection screen. The detector 101 may be a camera or a charge-coupled device (CCD).

[0050] Multiple sub-images are obtained by splitting the target image to be projected. The resolution of the target image is greater than the resolution of the light valve. The resolution of each frame of the sub-image after splitting is not greater than the resolution of the light valve, for example, it can be equal to the resolution of the light valve. For example, the resolution of the target image can be M×N, where M is the number of pixels in each row of the target image, and N is the number of pixels in each column. The resolution of the light valve is M1×N1, where M1 is the number of pixels in each row of the image that the light valve can project and display, and N1 is the number of pixels in each column. The resolution of each frame of the sub-image can be m1×n1, where m1 is the number of pixels in each row of the sub-image of each frame, and n1 is the number of pixels in each column. M, N, M1, N1, m1 and n1 are all positive integers greater than 1, and M is greater than M1, N is greater than N1, m1 is not greater than M1, and n1 is not greater than N1.

[0051] For example, the resolution of the target image can be 3840×2160, that is, M is 3840 and N is 2160. The resolution of the light valve can be 2880×1620, that is, M1 is 2880 and N1 is 1620. The resolution of the subframe image is 2715×1527, that is, m1 is 2715 (approximately 3840). One-tenth of 2160), n1 is 1527 (about 2160 The resolution of the target image is 3840×2160, which is greater than the resolution of the light valve, and the resolution of each sub-image is 2715×1527, which is less than the resolution of the light valve, 2880×1620.

[0052] In the embodiment of the present application, during the calibration phase of the galvanometer, the processor 10 is configured to split the galvanometer calibration image into a first sub-image and a second sub-image. In the first sub-frame, the galvanometer 60 in the lens assembly is moved to the first position, and the first sub-image is projected at the first display position of the display screen 130 through the lens assembly; in the second sub-frame, the galvanometer 60 in the lens assembly is moved to the second position, and the second sub-image is projected at the second display position of the display screen 130 through the lens assembly. Then, according to the offset between the first sub-image and the second sub-image captured by the detector 101, the first position and the second position of the galvanometer 60 are calibrated.

[0053] The laser projection device may also include a main control chip 00, referring to Figure 2 , the processor 10 can be connected to the main control chip 00. When the laser projection device projects and displays the galvanometer calibration image to be projected, the main control chip 00 can decode the image signal of the galvanometer calibration image and send the decoded image signal of the galvanometer calibration image to the processor 10 at a frequency of 60 Hz. Correspondingly, the processor 10 can receive the image signal of the decoded galvanometer calibration image sent by the main control chip 00. Afterwards, the processor 10 can split the received decoded image signal of the galvanometer calibration image into signals of the first sub-image and the second sub-image, so as to realize dividing the galvanometer calibration image into two frame sub-images.

[0054] In the embodiment of the present application, the processor 10 is connected to each laser driving assembly 20. After the processor 10 divides the galvanometer calibration image to be projected into the first sub-image and the second sub-image, it can output at least one enable signal corresponding to the three primary colors of each frame of the sub-image, and transmit the at least one enable signal to the corresponding laser driving assembly 20. The laser current control signal is used to instruct the laser driving assembly 20 to provide the corresponding laser driving current to the laser connected thereto to drive the laser to emit laser light. Among them, the laser current control signal can be a pulse width modulation (PWM) signal.

[0055] like Figure 2 As shown, the laser projection device may further include a power supply 150, a start control component 160 and a program storage component 170. The main control chip 100 is connected to the start control component 160 and the processor 10 respectively, the power supply 150 is connected to the laser drive component 20, and the program storage component 170 is connected to the processor 10.

[0056] The main control chip 100 sends a start command to the start control component 160. The start control component 160 starts working after receiving the start command, and outputs 1.1 volts (V), 1.8V, 3.3V, 2.5V and 5V to the display control component in sequence according to the power-on timing of the start control component 160 to power the processor 10. After the power supply voltage and timing are correct, the start control component 160 sends a power sense (POSENSE) signal and a power good (PWRGOOD) signal to the processor 10. After receiving the two control signals, the processor 10 reads the program from the external program storage component 170 and initializes it. At this time, the entire projection device starts working. The processor 10 configures the start control component 160 through the serial peripheral interface (SPI) communication, and instructs the start control component 160 to start powering the light valve 40. Then, the control component 160 is started to output three voltages to the light valve 40, namely, voltage bias (VBIAS) is 18V, voltage reset (VRST) is -14V, and voltage offset (VOFS) is 10V. After the voltage of the light valve 40 is normal, the light valve 40 starts to work. The processor 10 sends the primary color scale value of the sub-image to the light valve 40 through the high-speed serial interface (HSSI) at 594MHz to realize the sub-image. The power supply in the laser projection device is converted from 100V to 240V AC to DC by the power board to power each component.

[0057] like Figure 1 As shown, the laser projection device includes three laser driving components 20, and accordingly, the light source 30 includes three groups of lasers corresponding to the three laser driving components 20, and the three groups of lasers can be blue laser 301, red laser 302 and green laser 303, respectively, and the blue laser 301, red laser 302 and green laser 303 are respectively connected to the corresponding laser driving components 20. Among them, the blue laser 301 is used to emit blue laser, the red laser 302 is used to emit red laser, and the green laser 303 is used to emit green laser. The laser projection device can be called a three-color laser projection device.

[0058] The processor 10 outputs a blue PWM signal B_PWM corresponding to the blue laser 301 based on the blue primary color component of each frame of the sub-image, and outputs an enable signal B_EN corresponding to the blue laser 301 based on the lighting duration of the blue laser 301 in the driving cycle. Then, the blue PWM signal B_PWM and the enable signal B_EN corresponding to the blue primary color component of each frame of the sub-image are transmitted to the laser driving component 20, which is the driving component corresponding to the blue laser 301. The laser driving component 20 corresponding to the blue laser 301 can respond to the blue PWM signal B_PWM and the enable signal B_EN to provide the blue laser 301 with a corresponding laser driving current to drive the blue laser 301 to emit a blue laser.

[0059] The processor 10 outputs a red PWM signal R_PWM corresponding to the red laser 302 based on the red primary color component of each frame of the sub-image, and outputs an enable signal R_EN corresponding to the red laser 302 based on the lighting duration of the red laser 302 in the driving cycle. Then, the red PWM signal R_PWM and the enable signal R_EN corresponding to the red primary color component of each frame of the sub-image are transmitted to the laser driving component 20, which is the driving component corresponding to the red laser 302. The laser driving component 20 corresponding to the red laser 302 can respond to the red PWM signal R_PWM and the enable signal R_EN to provide the corresponding laser driving current to the red laser 302 to drive the red laser 302 to emit red laser.

[0060] The processor 10 outputs a green PWM signal G_PWM corresponding to the green laser 303 based on the green primary color component of each frame of the sub-image, and outputs an enable signal G_EN corresponding to the green laser 303 based on the lighting duration of the green laser 303 in the driving cycle. Then, the green PWM signal G_PWM and the enable signal G_EN corresponding to the green primary color component of each frame of the sub-image are transmitted to the laser driving component 20, which is the driving component corresponding to the green laser 303. The laser driving component 20 corresponding to the green laser 303 can respond to the green PWM signal G_PWM and the enable signal G_EN to provide the green laser 303 with a corresponding laser driving current to drive the green laser 303 to emit green laser.

[0061] After controlling the laser to start emitting laser, the processor 10 can control the light valve 40 to flip according to the primary color gradation value of the pixel in each frame of the sub-image, and realize the primary color gradation value by the length of time the micromirror in the light valve 40 flips, and forms the gray scale of the three primary colors of the corresponding pixel in conjunction with the corresponding color light irradiated on the light valve 40, and then project multiple frames of sub-images in sequence onto the display screen 130, and display the frame of sub-image to different positions of the display screen 130 by controlling the deflection of the galvanometer 60.

[0062] In the embodiment of the present application, the multiple sub-images include two sub-images. When the laser light emitted by each laser irradiates the light valve 40, the processor 10 can control the light valve 40 to flip according to the primary color gradation value of the pixel in each sub-image, so as to project the two sub-images sequentially onto the display screen 130. For example, the primary color gradation value can be a red, green, blue (RGB) gradation value.

[0063] like Figure 3 As shown, if the light source 30 in the laser projection device includes two groups of red lasers 302, a group of blue lasers 301 and a group of green lasers 303 that are integrated. The projection device can be called a full-color laser projection device. The blue laser 301 in the laser projection device is arranged between the red laser 302 and the green laser 303. Since the blue laser 301 can withstand a higher temperature, the blue laser 301 is arranged between the red laser 302 and the green laser 303. This arrangement is more conducive to the rapid heat dissipation of the red laser 302 and the green laser 303, so that the reliability of the integrated multiple groups of lasers is higher. The full-color laser projection device can also include four reflective lenses 70, a lens assembly 80, a diffusion wheel 90, a light pipe 100, a total internal reflection (TIR) ​​lens 110, a projection lens 120 and a display screen 130. Among them, the lens assembly 80 includes a first lens 801, a second lens 802 and a third lens 803, and each group of lasers is correspondingly provided with a reflective lens 70.

[0064] In the process of projecting and displaying the first sub-image, the blue laser light emitted by the blue laser 301 is reflected by the reflective lens 70 at the corresponding position, and is focused by the first lens 801, is homogenized by the diffusion wheel 90, and is homogenized by total reflection through the light guide 100. The red laser light emitted by the red laser 302 is reflected by the reflective lens 70 at the corresponding position, and is focused by the first lens 801, is homogenized by the diffusion wheel 90, and is homogenized by the total reflection through the light guide 100. The green laser light emitted by the green laser 303 is reflected by the reflective lens 70 at the corresponding position, and is focused by the first lens 801, is homogenized by the diffusion wheel 90, and is homogenized by the total reflection through the light guide 100. The blue laser, red laser and green laser after being homogenized by the light pipe 100 are shaped by the second lens 802 and the third lens 803 in a time-sharing manner and enter the TIR lens 110 for total reflection. During the process of the three primary color lights being irradiated to the light valve 40 in a timely manner, the processor 10 controls the light valve 40 to flip according to the primary color gradation value of the pixel in the first sub-image. The flipped light valve 40 reflects the light that has been totally reflected by the TIR lens 110, passes through the TIR lens 110 again, is deflected by the galvanometer 60, and is finally projected onto the display screen 130 through the projection lens 120, so as to display the first sub-image on the display screen 130.

[0065] Afterwards, the second sub-image is projected and displayed in sequence.

[0066] In the process of projecting and displaying each frame of sub-image, the processor 10 can transmit the galvanometer current control signal corresponding to a frame of sub-image to the galvanometer driving component 50, and the galvanometer current control signal is used to control the galvanometer driving component 50 to provide the galvanometer driving current to the galvanometer 60 to drive the galvanometer 60 to deflect. Among them, the galvanometer current control signals corresponding to different frame sub-images are different, thereby realizing the projection of multiple frame sub-images to different positions on the projection screen, thereby realizing the superposition display of the multiple frame sub-images, and then realizing the display of the target image on the display screen 130. In addition, in the process of projecting and displaying multiple frame sub-images, the current direction of the galvanometer driving current can change alternately, and the changing waveform of the galvanometer driving current can be a sine wave.

[0067] In the process of projecting and displaying each frame of sub-image, the light valve 40 receives the irradiation of the three primary colors of light in a timely manner, and when the light valve 40 receives the irradiation of the target primary color of the three primary colors of light, the processor 10 can transmit the galvanometer current control signal of the corresponding sub-image to the galvanometer drive component 50, and the galvanometer current control signal is used to control the galvanometer drive component to provide the galvanometer drive current to the galvanometer to drive the galvanometer 60 to deflect, and then the galvanometer 60 remains unchanged, thereby completing the display of a frame of sub-image. Then, when displaying the next frame of sub-image, the display control component 10 and the galvanometer drive component 50 can drive the galvanometer 60 to deflect again, and so on, so as to realize the projection and display of different frames of sub-images to different positions of the projection screen.

[0068] In the process of projecting and displaying the first sub-image, the light valve 40 receives the irradiation of the three primary colors of light sequentially, and when the light valve 40 receives the irradiation of the target primary color of the three primary colors of light, the processor 10 can transmit the first galvanometer current control signal to the galvanometer driving component 50. The first galvanometer current control signal is used to control the galvanometer driving component 50 to drive the galvanometer 60 to rotate to the first position.

[0069] In the process of projecting and displaying the second sub-image, the light valve 40 receives the irradiation of the three primary colors of light sequentially, and when the light valve 40 receives the irradiation of the target primary color of the three primary colors of light, the processor 10 can transmit the second galvanometer current control signal to the galvanometer driving component 50. The second galvanometer current control signal is used to control the galvanometer driving component 50 to drive the galvanometer 60 to rotate to the second position.

[0070] like Figure 4 As shown, in the process of projecting and displaying the first frame sub-image P1, the light valve 40 receives the irradiation of the three primary colors of light in a timely manner, and when the light valve 40 receives the irradiation of the blue primary color light among the three primary colors of light, the processor 10 can transmit the first galvanometer current control signal to the galvanometer driving component 50, and the galvanometer driving component 50 provides the first galvanometer driving current to the coil in the galvanometer 60, and the galvanometer 60 can rotate a certain angle under the drive of the first galvanometer driving current. In this way, the center point pixel in the first sub-image P1 can be offset by a certain distance relative to the coordinate origin o in the positive direction of the A axis, that is, the center point pixel in the first sub-image P1 is located at the position a of the A axis.

[0071] like Figure 5As shown, in the process of projecting and displaying the second frame sub-image P2, the light valve 40 receives the irradiation of the three primary colors of light in a timely manner, and when the light valve 40 receives the irradiation of the blue primary color light among the three primary colors of light, the processor 10 can transmit the second galvanometer current control signal to the galvanometer driving component 50, and the galvanometer driving component 50 provides the second galvanometer driving current to the coil in the galvanometer 60, and the galvanometer 60 can rotate a certain angle under the drive of the second galvanometer driving current. In this way, the center point pixel in the second sub-image P2 can be offset by a certain distance relative to the coordinate origin o in the negative direction of the A axis, that is, the center point pixel in the second sub-image P2 is located at the b position of the A axis.

[0072] Different frame sub-images correspond to different galvanometer current control signals, so the galvanometer 60 can be driven to deflect to different positions, so that the multiple frame sub-images are superimposed and displayed on the display screen 130, and the high-resolution target image can be displayed on a low-resolution laser projection device without losing the pixel information of the target image. The pixel offset needs to match the video signal in the system so that the galvanometer 60 moves in the correct way and direction to make the pixel position correct, the resolution improved, and the display image correct, so as to achieve the effect of doubling the pixels. Therefore, the movement of the galvanometer 60 needs to be calibrated and adjusted to match the most accurate position, and the pixels can be calibrated and checked.

[0073] In the embodiment of the present application, a special galvanometer calibration card is added to the DLP system. The galvanometer calibration card is added to the memory of the image processing chip from the application software. The galvanometer calibration card can be called and displayed for adjusting and matching the galvanometer pixel movement. Preferably, the galvanometer calibration image includes at least two of red pixels, green pixels, blue pixels, yellow pixels, and white pixels. Multiple colors are used to make a clear difference between the first sub-image and the second sub-image, so that the processor 10 can judge the image collected by the detector 101.

[0074] like Figure 6 As shown, in the embodiment of the present application, the image displayed by the galvanometer calibration chart is 32 pixels × 32 pixels, and includes five colors of pixels: red pixels (R), green pixels (G), blue pixels (B), yellow pixels (Y), and white pixels (W). Figure 6 The 32×32 pixel test chart in the image processing chip will repeatedly cover the entire DMD display area, that is, the galvanometer calibration chart written into the image processing chip is Figure 6 The repeated arrangement of 32×32 pixel cards covers the entire DMD. The embodiments of the present application are all adjusted and calibrated on the basis of the correct setting of the north-south (N / S) and east-west (E / W) directions of the normally viewed image. Figure 6This is the pixel arrangement state when the galvanometer 60 is not vibrating. The dotted frame contains 32×32 pixels, that is, the pixel arrangement state before being split into the first sub-image and the second sub-image.

[0075] In some embodiments, the galvanometer calibration image includes a horizontal white pixel group and a vertical white pixel group. The first sub-image and the second sub-image each include all horizontal white pixel groups and all vertical white pixel groups.

[0076] In some embodiments, the galvanometer calibration image includes a first horizontal red-green pixel group and a second horizontal red-green pixel group. The first horizontal red-green pixel group includes a red horizontal graphic located in the middle and green horizontal graphics located on the left and right sides, respectively, wherein the red horizontal graphic is split into a first sub-image and the green horizontal graphic is split into a second sub-image; the second horizontal red-green pixel group includes a green horizontal graphic located in the middle and red horizontal graphics located on the left and right sides, respectively, wherein the green horizontal graphic is split into the first sub-image and the red horizontal graphic is split into the second sub-image.

[0077] In some embodiments, the galvanometer calibration image includes a first vertical red-green pixel group and a second vertical red-green pixel group. The first vertical red-green pixel group includes a red vertical graphic located in the middle and green vertical graphics located at the upper and lower sides, respectively, wherein the red vertical graphic is split into a first sub-image and the green vertical graphic is split into a second sub-image. The second vertical red-green pixel group includes a green vertical graphic located in the middle and red vertical graphics located at the upper and lower sides, respectively, wherein the green vertical graphic is split into the first sub-image and the red vertical graphic is split into the second sub-image.

[0078] In some embodiments, the galvanometer calibration image includes a first vertical red, green, and blue pixel group and a second vertical red, green, and blue pixel group. The first vertical red, green, and blue pixel group includes a red vertical graphic located at the top, a green vertical graphic located in the middle, and a blue vertical graphic located at the bottom, wherein the green vertical graphic is split into a first sub-image, and the red vertical graphic and the blue vertical graphic are split into a second sub-image. The second vertical red, green, and blue pixel group includes a blue vertical graphic located at the top, a green vertical graphic located in the middle, and a red vertical graphic located at the bottom, wherein the red vertical graphic and the blue vertical graphic are split into the first sub-image, and the green vertical graphic is split into the second sub-image.

[0079] In some embodiments, the galvanometer calibration image includes a horizontal blue pixel group. The horizontal blue pixel group includes a blue horizontal left pattern and a blue horizontal right pattern, wherein the blue horizontal left pattern is split into a first sub-image, and the blue horizontal right pattern is split into a second sub-image.

[0080] In some embodiments, the galvanometer calibration image includes a horizontal yellow pixel group and a vertical yellow pixel group. The horizontal yellow pixel group is split into a red horizontal pattern in the first sub-image and a green horizontal pattern in the second sub-image, and the vertical yellow pixel group is split into a green vertical pattern in the first sub-image and a red vertical pattern in the second sub-image.

[0081] like Figure 6 As shown, in the embodiment of the present application, the galvanometer calibration image includes 5 pixel groups in the horizontal direction. The top is a horizontal white pixel group, including 28 white pixels. The second horizontal pixel group below is the first horizontal red-green pixel group, with two rows of 2×4 in the middle, a total of 8 red pixels, 5 green pixels on the right of the two rows of red pixels and aligned with a row of red pixels above the two rows of red pixels, 5 green pixels on the left of the two rows of red pixels and aligned with a row of red pixels below the two rows of red pixels. The third horizontal pixel group below is the second horizontal red-green pixel group, with two rows of 2×4 in the middle, a total of 8 green pixels, 5 red pixels on the right of the two rows of green pixels and aligned with a row of green pixels above the two rows of green pixels, 5 red pixels on the left of the two rows of green pixels and aligned with a row of green pixels below the two rows of green pixels. The fourth horizontal pixel group below is a horizontal yellow pixel group, including a row of 23 yellow pixels. The fifth horizontal pixel group is a horizontal blue pixel group, including a row of 32 blue pixels.

[0082] In the vertical direction, the galvanometer calibration image includes 6 vertical pixel groups. The leftmost is the first vertical pixel group. The first vertical pixel group is a vertical white pixel group, including 25 white pixels. The second vertical pixel group is the first vertical red, green and blue pixel group, with 5 red pixels at the top, 5 green pixels in the middle, and 5 blue pixels at the bottom. 3 pixels of different colors are aligned in one column. The third vertical pixel group is the first vertical red and green pixel group, with 2×3 in the middle, a total of 6 red pixels, 4 green pixels on the top, aligned with the left column of the two columns of red pixels, and 4 green pixels on the bottom, aligned with the right column of the two columns of red pixels. The fourth vertical pixel group is the second vertical red and green pixel group, with 2×3 in the middle, a total of 6 green pixels, 4 red pixels on the top, aligned with the left column of the two columns of green pixels, and 4 red pixels on the bottom, aligned with the right column of the two columns of green pixels. The fifth vertical pixel group is the second vertical red, green and blue pixel group, with 5 blue pixels at the top, 5 green pixels in the middle and 5 red pixels at the bottom, and 3 pixels of different colors are aligned in one column. The sixth vertical pixel group is a vertical yellow pixel group, including a column of 20 yellow pixels. In this 32×32 pixel area, except for the above pixels, the remaining pixels are all black pixels, that is, the grayscale of these pixels is 0.

[0083] like Figure 7 and Figure 8 As shown, Figure 7 is a schematic diagram of the first sub-image after the galvanometer calibration image is split. Figure 8 It is a schematic diagram of the second sub-image after the galvanometer calibration image is split.

[0084] like Figure 7 As shown, all white pixels are in the first sub-image. All double-row and double-column red pixels and green pixels are in the first sub-image. The yellow pixels in the galvanometer calibration image are split into red pixels and green pixels (yellow is a superposition of red and green), where the red pixel row is in the first sub-image and the green pixel column is in the first sub-image. The 16 blue pixels on the left half of the 5th row of blue pixels in the horizontal direction are in the first sub-image. The 5 green pixels in the middle of the 2nd column in the vertical direction are in the first sub-image. The 5 blue pixels on the top and the 5 red pixels on the bottom of the 5th column are in the first sub-image.

[0085] like Figure 8 As shown, all white pixels are also in the second sub-image. All single-row and single-column red pixels and green pixels aligned with double-row and double-column red pixels and green pixels are in the second sub-image. The yellow pixels in the galvanometer calibration image are split into red pixels and green pixels, the green pixel rows are in the second sub-image, and the red pixel columns are in the second sub-image. The 16 blue pixels on the right half of the 5th row of blue pixels in the horizontal direction are in the second sub-image. The 5 red pixels on the top and 5 blue pixels on the bottom of the 2nd column in the vertical direction are in the second sub-image. The 5 green pixels in the middle of the 5th column are in the second sub-image.

[0086] In the embodiment of the present application, the processor 10 is further configured to: calibrate the rotation direction of the galvanometer according to the offset direction between the first sub-image and the second sub-image captured by the detector, thereby calibrating the phase polarity of the sub-frame.

[0087] The processor 10 configures the phase polarity of the subframe. Each subframe chart corresponds to a position of the galvanometer. The two positions of the galvanometer are represented by position A and position B. When the first subframe is output, the galvanometer moves to position A or position B; when the second subframe is output, the galvanometer moves to position B or position A. Whether the first subframe corresponds to position A or position B of the galvanometer, it is necessary to adjust the subframe phase polarity of the subframe in the application software. The normal default image display direction is N / S and E / W. The subframe image processing allocates the subimage projection position according to this image direction. The projection positions of the first subimage and the second subimage are directional. The subframe direction must be correct, and the final displayed image is correct. If the direction is configured in reverse, the displayed image will have image quality problems such as ghosting. Therefore, which phase of the first subimage and the second subimage is displayed first and which phase is displayed later must be set correctly. This is the subframe phase polarity configuration. After the adjustment is correct, this configuration is written into the software and downloaded to the system for solidification. After the configuration is completed, the subframe phase polarity is correct every time it is powered on.

[0088] The position of the first sub-image is determined by the moving position of the galvanometer. The two positions of the two-dimensional galvanometer are position A and position B. If the galvanometer is in position A, the first sub-image is output, and the second sub-image is output when the galvanometer is in position B, the image display is correct. If the galvanometer is in position A, the second sub-image is output, and the galvanometer is in position B. The image display is wrong. The wrong image display will lead to abnormal resolution, and image quality failures such as image blur or ghosting may also occur. The solution to the incorrect sub-frame phase polarity configuration includes: by changing the galvanometer drive waveform, the galvanometer position A and B positions are changed in turn, and the galvanometer position A and B positions are exchanged, so that the galvanometer outputs the first sub-image in position A, and the galvanometer outputs the second sub-image in position B, and the sub-frame phase polarity is configured correctly. In the embodiment of the present application, the second word image is located at the lower left or lower right of the first group of images, which is correct for the sub-frame phase polarity.

[0089] like Fig. 9 and Fig.10 As shown, Fig. 9 and Fig.10 These are all examples of the correct phase of the galvanometer in the embodiments of the present application. In the second horizontal pixel group, the double rows of 2×4 red pixels in the first sub-image are at the top. Fig. 9 The single row of 5 green pixels in the second sub-image is below the double row of red pixels. Fig.10 The single row of 5 green pixels in the second sub-image is also below the double row of red; in the third horizontal pixel group, the 2×4 green pixels of the middle sub-frame 2 are at the top, Fig. 9 In the second sub-image, the single row of 5 red pixels is below the double row of green pixels. Fig.10The single row of 5 red pixels in the second sub-image is also below the double row of green pixels; the red pixels of the first sub-image in the 4th horizontal pixel group are above the green pixels of the second sub-image; the left half of the blue pixels of the first sub-image in the 5th horizontal pixel group are above the right half of the blue pixels of the second sub-image. In summary, the pixels of the first sub-image are shifted upward relative to the second sub-image, and the pixels of the second sub-image are shifted downward relative to the first sub-image, so Fig. 9 and Fig.10 The subframe phase polarity configuration in is correct, Fig. 9 and Fig.10 The Galvo Calibration Chart is a graphic showing the correct chart.

[0090] like Fig.11 and Fig.12 As shown, Fig.11 and Fig.12 These are all examples of galvanometer phase errors in the embodiments of the present application. The pixels of the first sub-image are offset downward relative to the pixels of the second sub-image, and the pixels of the second sub-image are offset upward relative to the pixels of the first sub-image. Fig.11 and Fig.12 The subframe phase polarity configuration shown is incorrect. You need to change the subframe phase polarity and change the galvanometer phase by switching the galvanometer position to switch the phase of the first sub-image and the second sub-image until the pixel offset direction of the galvanometer calibration chart reaches Fig. 9 or Fig.10 As shown.

[0091] like Fig.13 As shown, the corresponding pixel movement of the two-dimensional galvanometer moves along one of the two diagonal axes. Under the normal image directions N / S and E / W, the pixel movement direction of the galvanometer moves along the diagonal A axis, that is, Fig. 9 Or move along the diagonal B axis, that is Fig.10 Offset direction shown.

[0092] In the embodiment of the present application, the processor 10 is further configured to: calibrate the rotation amplitude of the galvanometer according to the offset distance between the first sub-image and the second sub-image captured by the detector, thereby calibrating the offset distance of the sub-frame.

[0093] When the image direction (N / S and E / W) is set correctly, the galvanometer calibration image is projected and displayed, and the subframe phase polarity of the galvanometer must also be set correctly, such as Fig. 9 As shown, relative to Figure 6 Pixel offset when the galvanometer is not working. All pixels in the second sub-image are shifted along the A axis relative to the first sub-image. The white pixel moves to the lower right by 1 / 2 pixel distance P. In the second horizontal pixel group, the five green pixels in the second sub-image to the right of the double rows of red pixels in the first sub-image are moved to the right by a 1 / 2 pixel distance P in the horizontal direction, and Figure 6 Compared to the galvo calibration image shown, the red pixels are different from the green pixels. Similarly, in the third horizontal pixel group, the two rows of green pixels in the first sub-image and the five red pixels in the second sub-image also have a gap in the horizontal direction. In the 5th row of horizontal pixel groups, the left half of the blue pixels in the first sub-image and the right half of the blue pixels in the second sub-image also have a gap in the horizontal direction. gap.

[0094] Similarly, if Fig.10 As shown in FIG. 1 , the pixels of the galvanometer mirror move along the diagonal direction of the B axis. Compared with the galvanometer mirror calibration image when the galvanometer mirror is not working, all pixels of the second sub-image move along the diagonal direction of the B axis (towards the lower left) relative to the first sub-image. Distance, in the horizontal direction and vertical direction respectively moved to the left and down by 1 / 2 pixel distance P. Fig.10 As shown, the white pixels are moved to the lower left corner. In the second horizontal pixel group, the five green pixels in the second sub-image to the right of the double rows of red pixels in the first sub-image are moved to the left by a 1 / 2 pixel distance P in the horizontal direction, and Figure 6 Compared with the galvanometer calibration image shown, the green pixels and the two rows of red pixels overlap by 1 / 2 pixel in the horizontal direction; similarly, in the third horizontal pixel group, the two rows of green pixels in the first sub-image and the five red pixels in the second sub-image also overlap by 1 / 2 pixel in the horizontal direction; in the fifth row of horizontal pixel group, the right half of the blue pixels in the second sub-image are moved by 1 / 2 pixel in the lower left direction along the B-axis diagonal relative to the left half of the blue pixels in the first sub-image. The distance in the horizontal direction is There is an overall overlap of 1 / 4 pixel.

[0095] The diagonal axis along which the two sub-images move must be set correctly to ensure correct processing and display of ultra-high-resolution image data and obtain the best image quality. In order to obtain the most accurate pixel offset distance, before performing the galvanometer pixel calibration, the focus of the projector must be adjusted to obtain the clearest image and the best focus resolution. Because the galvanometer calibration image is 32×32 pixels repeated multiple times in the entire DMD display area and is composed of many 32×32 pixel modules, the galvanometer pixel calibration can be used to perform pixel calibration on the galvanometer. In the application software, the analog gain of the galvanometer drive waveform, that is, the digital to analog converter (DAC) gain parameter, can be adjusted until the pixel offset distance reaches the preset effect. For example Fig.10 As shown, until the 2nd horizontal pixel group, the right green pixel in the second sub-image is located between the middle two rows of red pixels in the first sub-image, and in the 3rd horizontal pixel group, the right red pixel in the second sub-image is located between the middle two rows of green pixels in the first sub-image.

[0096] Increasing the DAC gain will cause the right row of green pixels in the second horizontal pixel group and the right row of red pixels in the third horizontal pixel group on the projected image to move downward. Reducing the DAC gain will cause the right row of green pixels in the second horizontal pixel group and the right row of red pixels in the third horizontal pixel group on the projected image to move upward. Fig. 9 and Fig.10 Two possible correct galvanometer calibration images are shown. After debugging the correct DAC gain parameters, write this DAC gain into the system application program, and the calibration of the galvanometer is completed. In laser projection equipment using galvanometers, galvanometer calibration is required to display ultra-high resolution images and achieve the required image quality.

[0097] The laser projection device and galvanometer calibration method provided in the embodiment of the present application, split the galvanometer calibration image into a first sub-image and a second sub-image through a processor, and project and display them in a first sub-frame and a second sub-frame respectively. And control the galvanometer in the lens assembly to flip, move the galvanometer to a first position in the first sub-frame, so as to project the first sub-image at the first display position of the display screen; move the galvanometer to a second position in the second sub-frame, so as to project the second sub-image at the second display position of the display screen. Then, according to the offset between the first sub-image and the second sub-image collected by the detector, the first position and the second position of the galvanometer are calibrated, wherein the galvanometer calibration pattern used has significant color features, and the split first sub-image and the second sub-image also have color features and differences respectively, so it is possible to accurately judge whether the offset between the first sub-image and the second sub-image is consistent with the preset, thereby solving the problem of low calibration accuracy of the galvanometer of the laser projection device.

[0098] In some embodiments, the projection method of the input image can also be changed, and the galvanometer calibration image is reversely projected, and the pixel calibration method remains unchanged. Fig.14 As shown, Fig.14 This is a schematic diagram of the reverse-projected galvanometer calibration image, which is equivalent to Figure 6 All pixels in the image are arranged vertically in reverse order.

[0099] Correspondingly, such as Fig.15 and Fig.16 As shown, Fig.15 Schematic diagram of the first sub-image after the back-projected galvanometer calibration image is split. Fig.16 Schematic diagram of the second sub-image after splitting the back-projected galvanometer calibration image.

[0100] In reverse projection mode, the correct projection image is as follows: Fig.17 and Fig.18 As shown, adjust to Fig.17 or Fig.18 As shown in the image, the correct parameter configuration has been achieved and pixel calibration is completed.

[0101] In reverse projection mode, the wrong projection image is as follows Fig.19 and Fig. 20 If Fig.19 or Fig. 20 The image shown here indicates that the galvanometer pixel calibration has failed. You need to continue adjusting the parameters until the projected image is as shown below. Fig.17 or Fig.18 Until one of the ones shown.

[0102] In some embodiments, the present application provides a galvanometer calibration method, which is applied to the laser projection device provided in the above-mentioned embodiment of the present application, such as Fig.21 As shown, the method comprises the following steps:

[0103] S101 , splitting a galvanometer calibration image into a first sub-image and a second sub-image.

[0104] S102 . In a first subframe, move a galvanometer in a lens assembly to a first position, and project a first sub-image at a first display position on a display screen through the lens assembly.

[0105] S103 . In a second subframe, move the galvanometer in the lens assembly to a second position, and project a second sub-image at a second display position on the display screen through the lens assembly.

[0106] S104 , calibrating the first position and the second position of the galvanometer according to the offset between the first sub-image and the second sub-image acquired by the detector.

[0107] It should be noted that the above steps S102 and S103 are usually performed alternately and repeatedly, and step S104 is performed synchronously during the process of performing steps S102 and S103.

[0108] In some embodiments, the embodiments of the present application further provide an electronic device, comprising: a memory and a processor, wherein the memory is used to store a computer program; and the processor is used to enable the electronic device to implement the galvanometer calibration method described in any of the above embodiments when executing the computer program.

[0109] In some embodiments, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a computing device, the computing device implements the galvanometer calibration method described in any of the above embodiments.

[0110] In some embodiments, the embodiments of the present application provide a computer program product. When the computer program product is run on a computer, the computer implements the galvanometer calibration method described in any of the above embodiments.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0112] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A laser projection device, characterized in that: include: a lens assembly configured to project the optical signal; a display screen configured to present a projected image; a detector configured to collect the projected image; A processor configured to split the galvanometer calibration image into a first sub-image and a second sub-image; In a first subframe, the galvanometer in the lens assembly is moved to a first position, and the first sub-image is projected at a first display position on the display screen through the lens assembly; In a second subframe, the galvanometer in the lens assembly is moved to a second position, and the second sub-image is projected at a second display position on the display screen through the lens assembly; The first position and the second position of the galvanometer are calibrated according to the offset between the first sub-image and the second sub-image collected by the detector.

2. The laser projection device according to claim 1, characterized in that: The processor is further configured to calibrate the first position and the second position of the galvanometer according to the offset between the first sub-image and the second sub-image acquired by the detector, including: The rotation direction of the galvanometer is calibrated according to the offset direction between the first sub-image and the second sub-image collected by the detector.

3. The laser projection device according to claim 1, characterized in that: The processor is further configured to: calibrate the first position and the second position of the galvanometer according to the offset between the first sub-image and the second sub-image collected by the detector, including: The rotation amplitude of the galvanometer is calibrated according to the offset distance between the first sub-image and the second sub-image collected by the detector.

4. The laser projection device according to claim 1, characterized in that: The galvanometer calibration image includes a first horizontal red and green pixel group and a second horizontal red and green pixel group; The first horizontal red and green pixel group includes a red horizontal pattern located in the middle and green horizontal patterns located on the left and right sides respectively, wherein the red horizontal pattern is split into the first sub-image, and the green horizontal pattern is split into the second sub-image; The second horizontal red and green pixel group includes a green horizontal pattern in the middle and red horizontal patterns on the left and right sides, wherein the green horizontal pattern is split into the first sub-image and the red horizontal pattern is split into the second sub-image.

5. The laser projection device according to claim 1, characterized in that: The galvanometer calibration image includes a first vertical red and green pixel group and a second vertical red and green pixel group; The first vertical red and green pixel group includes a red vertical pattern located in the middle and green vertical patterns located at the upper and lower sides, respectively, wherein the red vertical pattern is split into the first sub-image, and the green vertical pattern is split into the second sub-image; The second vertical red and green pixel group includes a green vertical pattern in the middle and red vertical patterns at the upper and lower sides, respectively, wherein the green vertical pattern is split into the first sub-image and the red vertical pattern is split into the second sub-image.

6. The laser projection device according to claim 1, characterized in that: The galvanometer calibration image includes a first vertical red, green, and blue pixel group and a second vertical red, green, and blue pixel group; The first vertical red, green and blue pixel group includes a red vertical pattern located at the top, a green vertical pattern located in the middle and a blue vertical pattern located at the bottom, wherein the green vertical pattern is split into the first sub-image, and the red vertical pattern and the blue vertical pattern are split into the second sub-image; The second vertical red, green and blue pixel group includes a blue vertical graphic at the top, a green vertical graphic at the middle and a red vertical graphic at the bottom, wherein the red vertical graphic and the blue vertical graphic are split into the first sub-image, and the green vertical graphic is split into the second sub-image.

7. The laser projection device according to claim 1, characterized in that: The galvanometer calibration image includes a horizontal blue pixel group; The horizontal blue pixel group includes a blue horizontal left pattern and a blue horizontal right pattern, wherein the blue horizontal left pattern is split into the first sub-image and the blue horizontal right pattern is split into the second sub-image.

8. The laser projection device according to claim 1, characterized in that: The galvanometer calibration image includes a horizontal yellow pixel group and a vertical yellow pixel group; The horizontal yellow pixel group is split into a red horizontal pattern in the first sub-image and a green horizontal pattern in the second sub-image; The vertical yellow pixel group is split into a green vertical pattern in the first sub-image and a red vertical pattern in the second sub-image.

9. The laser projection device according to claim 1, characterized in that: The galvanometer calibration image includes a horizontal white pixel group and a vertical white pixel group; The first sub-image and the second sub-image each include all of the horizontal white pixel groups and the vertical white pixel groups.

10. A galvanometer calibration method, characterized in that: Applied to laser projection equipment, the method comprises: Splitting the galvanometer calibration image into a first sub-image and a second sub-image; In a first subframe, a galvanometer in the lens assembly is moved to a first position, and the first sub-image is projected at a first display position of a display screen through the lens assembly; In a second subframe, the galvanometer in the lens assembly is moved to a second position, and the second sub-image is projected at a second display position on the display screen through the lens assembly; The first position and the second position of the galvanometer are calibrated according to the offset between the first sub-image and the second sub-image collected by the detector.

Images