Laser projection apparatus and laser projection image display method

Abstract

A laser projection apparatus, comprising: an ultra-short-focus lens (401) which comprises a reflector (4011) for reflecting an image beam; and N image capturing cameras (402) which are configured to capture images comprising a projected picture and a projection screen. A vertical distance between the image capturing cameras (402) and a first plane (YOZ) is smaller than or equal to half the width of the laser projection apparatus, a vertical distance between the image capturing cameras (402) and a second plane (XOZ) is smaller than or equal to a vertical distance between an optical axis of the ultra-short-focus lens (401) and an upper surface of the laser projection apparatus, and a vertical distance between the image capturing cameras (402) and a third plane (XOY) is smaller than or equal to a depth of the laser projection apparatus. The first plane (YOZ) is a plane formed by a first coordinate axis (Y) and a second coordinate axis (Z), the second plane (XOZ) is a plane formed by a third coordinate axis (X) and the second coordinate axis (Z), the third plane (XOY) is a plane formed by the third coordinate axis (X) and the first coordinate axis (Y), and the first coordinate axis (Y), the second coordinate axis (Z) and the third coordinate axis (X) are respectively consistent with directions corresponding to the height, depth and width of the laser projection apparatus, thereby realizing automatic correction. Further provided is a laser projection image display method.

Description

Laser projection device and laser projection image display method

[0001] This application claims priority to Chinese patent application No. 202410386134.5 filed on March 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to display technology, and more specifically, to a laser projection device and a laser projection image display method. Background Art

[0003] Ultra-short-throw laser projection equipment has developed rapidly in recent years. Ultra-short-throw lenses have a relatively short throw, allowing for large-scale projection at short distances, and have been widely used.

[0004] However, due to the high position sensitivity of the ultra-short-throw laser projection device, the device may move, and the projected image may be deformed or distorted, resulting in poor display effect. Therefore, the position of the ultra-short-throw laser projection device needs to be adjusted.

[0005] However, it is difficult for users to adjust the position of the ultra-short-throw laser projection device, which brings inconvenience to users and results in a poor user experience. Summary of the Invention

[0006] The embodiments of the present application provide a laser projection device and a laser projection image display method, which can be used to solve the problem in the related art that when the position of the ultra-short-throw laser projection device moves, the projection image display effect is poor, and it is difficult for the user to adjust the position of the ultra-short-throw laser projection device, resulting in a poor user experience.

[0007] In a first aspect, an embodiment of the present application provides a laser projection device, comprising:

[0008] An ultra-short-throw lens includes a reflector for reflecting an image beam to display a projection image on a projection screen;

[0009] N imaging cameras, wherein a vertical distance between the imaging camera and a first plane is less than or equal to half the width of the laser projection device, a vertical distance between the imaging camera and a second plane is less than or equal to a vertical distance between the optical axis of the ultra-short focus lens and the upper surface of the laser projection device, and a vertical distance between the imaging camera and a third plane is less than or equal to the depth of the laser projection device; the imaging cameras are used to capture an image including a projected image and a projection screen, and the image is used to adjust the position of the laser projection device and / or calibrate the projected image;

[0010] Wherein, N is a natural number greater than or equal to 1;

[0011] The first plane is a plane formed by the first coordinate axis and the second coordinate axis, the second plane is a plane formed by the third coordinate axis and the second coordinate axis, and the third plane is a plane formed by the third coordinate axis and the first coordinate axis;

[0012] The intersection of the first coordinate axis, the second coordinate axis and the third coordinate axis is the intersection of the optical axis of the ultra-short focus lens and the reflector. The first coordinate axis, the second coordinate axis and the third coordinate axis are respectively consistent with the directions corresponding to the height, depth and width of the laser projection device. The upper surface is the surface of the laser projection device that is parallel to the second plane and away from the second plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the implementation methods in the embodiments of the present application or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0014] FIG1 is a schematic structural diagram of an ultra-short-throw laser projection device in the related art;

[0015] FIG2 is a schematic diagram of a projection of an ultra-short-throw laser projection device provided in an embodiment of the present application;

[0016] FIG3 is a schematic diagram of the projection principle of an ultra-short-throw laser projection device provided in an embodiment of the present application;

[0017] FIG4 is a schematic structural diagram of a laser projection device provided in an embodiment of the present application;

[0018] FIG5 is a schematic structural diagram of an ultra-short-throw lens provided in an embodiment of the present application;

[0019] FIG6 is a schematic diagram showing the positional relationship between an imaging camera and a projection screen according to an embodiment of the present application;

[0020] FIG7 is a schematic diagram of the spatial structure of a laser projection device provided in an embodiment of the present application;

[0021] FIG8 is a second schematic diagram of the positional relationship between an imaging camera and a projection screen provided in an embodiment of the present application;

[0022] FIG9 is a side view of a laser projection device provided in an embodiment of the present application;

[0023] FIG10 is a top view of a laser projection device provided in an embodiment of the present application;

[0024] FIG11 is a second top view of a laser projection device provided in an embodiment of the present application;

[0025] FIG12 is a third schematic diagram of the positional relationship between an imaging camera and a projection screen provided in an embodiment of the present application;

[0026] FIG13 is a third top view of a laser projection device provided in an embodiment of the present application;

[0027] FIG14 is a fourth top view of a laser projection device provided in an embodiment of the present application;

[0028] FIG15 is a fifth top view of a laser projection device provided in an embodiment of the present application;

[0029] FIG16 is a schematic flow chart of a laser projection image display method provided in an embodiment of the present application;

[0030] FIG17 is a schematic diagram of a feature map card provided in an embodiment of the present application;

[0031] FIG18 is a schematic diagram of a shooting range of an imaging camera provided in an embodiment of the present application;

[0032] FIG19 is a schematic flow chart of a method for correcting a projection image according to an embodiment of the present application;

[0033] FIG20 is a schematic diagram of a temperature drift correction process provided by an embodiment of the present application;

[0034] Figure 21 is a schematic diagram of a focus chart provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode 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, not all of the embodiments.

[0036] It should be noted that the brief descriptions of terms in this application are only for the purpose of facilitating the understanding of the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and usual meanings.

[0037] In addition, the terms "comprises" and "comprising" 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 those components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0038] FIG1 is a schematic structural diagram of an ultra-short-throw laser projection device in related art. Referring to FIG1 , the ultra-short-throw laser projection device may include a laser light source 101 , an optical machine 102 , and an ultra-short-throw lens 103 .

[0039] In addition to the above modules, the ultra-short-throw laser projection equipment can also include: various driver boards, heat dissipation modules, human eye protection modules, remote control modules, audio, wifi and other related modules, etc., which are not shown one by one in Figure 1.

[0040] Figure 2 is a projection schematic diagram of an ultra-short-focus laser projection device provided in an embodiment of the present application, and Figure 3 is a schematic diagram of the projection principle of an ultra-short-focus laser projection device provided in an embodiment of the present application. Combined with Figures 2 and 3, the ultra-short-focus laser projection device is based on the reflector 1031 in the ultra-short-focus lens 103, which reflects light onto the projection screen 105, so that the picture is displayed on the projection screen 105.

[0041] As can be seen from the above, when an ultra-short-throw laser projector is projecting an image, the light needs to be reflected upwards by a reflector. Therefore, the light emitted by the ultra-short-throw laser projector must be strictly aligned with the projection screen, and the position sensitivity is high. Even if the ultra-short-throw laser projector is slightly shifted, it can cause deformation or distortion of the projected image, resulting in poor display quality. For users, adjusting the ultra-short-throw laser projector is difficult, causing inconvenience and resulting in a poor user experience.

[0042] At the same time, ultra-short-focus lenses are highly sensitive to temperature. During use, as the temperature changes, some lenses in the ultra-short-focus lens may undergo slight deformation, resulting in poor display effects of the projected image.

[0043] Based on this, the present application provides a laser projection device, which includes N imaging cameras. The imaging cameras can capture images including the projection image and the projection screen. Based on the captured images, the position changes and clarity changes of the projection image can be monitored in real time and adjusted in real time. Specifically, the position of the laser projection device can be adjusted, and the projection image can also be automatically corrected by software. There is no need for the user to manually adjust the position of the laser projection device, and automatic screen entry can be achieved, thereby improving the user experience. At the same time, the present application can also automatically correct when part or all of the projection image is blurred or out of focus due to temperature drift, so as to improve the clarity of the projection image, effectively avoiding the problem of reduced image clarity due to temperature drift, and improving the display effect of the projection image.

[0044] The laser projection equipment of the present application may be an ultra-short-throw laser TV, an ultra-short-throw laser projection equipment, or an ultra-short-throw equipment with other light sources, etc. The present application does not limit the type of laser projection equipment.

[0045] The following detailed description of the technical solution of the present application is provided in conjunction with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0046] FIG4 is a schematic structural diagram of a laser projection device provided in an embodiment of the present application. Referring to FIG4 , the laser projection device includes:

[0047] The ultra-short-focus lens 401 includes a reflector for reflecting the image beam to display the projection image on the projection screen;

[0048] N imaging cameras 402, wherein the vertical distance between the imaging camera 402 and a first plane is less than or equal to the half-width of the laser projection device, the vertical distance between the imaging camera 402 and a second plane is less than or equal to the vertical distance between the optical axis of the ultra-short focus lens 401 and the upper surface of the laser projection device, and the vertical distance between the imaging camera 402 and a third plane is less than or equal to the depth of the laser projection device; the imaging cameras 402 are used to capture images including the projected image and the projection screen, and the images are used to adjust the position of the laser projection device and / or calibrate the projected image;

[0049] Wherein, N is a natural number greater than or equal to 1;

[0050] The first plane is a plane formed by the first coordinate axis and the second coordinate axis, the second plane is a plane formed by the third coordinate axis and the second coordinate axis, and the third plane is a plane formed by the third coordinate axis and the first coordinate axis;

[0051] The intersection of the first coordinate axis, the second coordinate axis and the third coordinate axis is the intersection of the optical axis of the ultra-short focus lens 401 and the reflector. The first coordinate axis, the second coordinate axis and the third coordinate axis are respectively consistent with the directions corresponding to the height, depth and width of the laser projection device. The upper surface is the surface of the laser projection device that is parallel to the second plane and away from the second plane.

[0052] In one implementation scenario, in addition to the ultra-short-focus lens 401, the laser projection device also includes a light source and an optical engine. The optical engine may include a light valve modulation device. The light beam emitted by the light source is incident on the optical engine and modulated by the light valve modulation device to obtain an image beam, which is then emitted to the ultra-short-focus lens 401. Figure 5 is a schematic structural diagram of an ultra-short-focus lens provided in an embodiment of the present application. The ultra-short-focus lens 401 may include a reflector 4011 and multiple other lenses 4012. The image beam is transmitted to the reflector 4011 through the multiple lenses and reflected by the reflector 4011 onto the projection screen to achieve projection.

[0053] In some embodiments, the throw ratio of the ultra-short-throw lens 401 is less than or equal to 0.5. One calculation method for the throw ratio is: the distance from the intersection of the last lens element of the ultra-short-throw lens 401 and the optical axis of the ultra-short-throw lens 401 to the projection screen / the width of the projected image. The last lens element of the ultra-short-throw lens 401 is the reflector 4011.

[0054] In some embodiments, the sum of the shooting ranges of the N imaging cameras 402 is larger than the size of the projection screen.

[0055] There may be one or more imaging cameras 402. In one implementation scenario, when N is a natural number greater than 1, it indicates that there are multiple imaging cameras 402, and the sum of the shooting ranges of the multiple imaging cameras 402 is the sum of the shooting ranges of each imaging camera 402.

[0056] In another implementation scenario, when N is 1, it indicates that there is one imaging camera 402 . In this case, the sum of the shooting ranges of the N imaging cameras 402 is the shooting range of the imaging camera 402 , and the shooting range only needs to be larger than the size of the projection screen.

[0057] Since the projection image presented by the laser projection device is usually of a certain size, in order to achieve automatic screen insertion, the size of the projection image can be increased and then calibrated to the required size. The size of the projection image in this application can be regarded as the calibrated size, at which point the size of the projection image is consistent with the size of the projection screen.

[0058] Taking a single imaging camera 402 as an example, FIG6 is a schematic diagram illustrating the positional relationship between an imaging camera and a projection image according to an embodiment of the present application. Referring to FIG6 , ABCD represents the projection image or screen, EFGK represents the shooting range of the imaging camera 402, and Limg / 2 represents the half diagonal of the shooting range, i.e., half of the diagonal of the shooting range. The first plane is the YOZ plane, the second plane is the XOZ plane, and the third plane is the XOY plane.

[0059] FIG7 is a schematic diagram of the spatial structure of a laser projection device provided in an embodiment of the present application. As shown in FIG6 and FIG7 , the first coordinate axis is the Y-axis, which corresponds to the height of the laser projection device; the second coordinate axis is the Z-axis, which corresponds to the depth of the laser projection device; and the third coordinate axis is the X-axis, which corresponds to the width of the laser projection device. Point O, where the X-axis, Y-axis, and Z-axis intersect, is the intersection of the optical axis of the ultra-short-throw lens 401 and the reflector 4011.

[0060] The center point of the projection image is O', and a plane X'O'Y' where the projection image is located is established based on O', wherein X' is parallel to the third coordinate axis X axis, and Y' is parallel to the first coordinate axis Y axis.

[0061] It should be noted that the second coordinate axis Z is the optical axis of the ultra-short-throw lens 401. The second plane XOZ and the first plane YOZ both contain the optical axis of the ultra-short-throw lens 401 and are perpendicular to the plane X'O'Y' where the projection image is located. The third plane XOY is parallel to the plane X'O'Y' where the projection image is located.

[0062] The coordinates of the imaging camera 402 are labeled (x, y, z). The absolute value of x represents the vertical distance between the imaging camera 402 and the first plane YOZ. When the imaging camera 402 is located to the right of the optical axis of the ultra-short-throw lens 401, x > 0; when the imaging camera 402 is located to the left of the optical axis, x < 0. The absolute value of y represents the vertical distance between the imaging camera 402 and the second plane XOZ. When the imaging camera 402 is located above the optical axis of the ultra-short-throw lens 401, y > 0; when the imaging camera 402 is located below the optical axis, y < 0. The absolute value of z represents the vertical distance between the imaging camera 402 and the third plane XOY. When the imaging camera 402 is far from the projection screen, z > 0; when the imaging camera 402 is close to the projection screen, z < 0.

[0063] Since the imaging camera 402 needs to be located inside the laser projection device, the placement position (x, y, z) of the imaging camera 402 must meet the following requirements: the absolute value of x is less than or equal to the half-width of the laser projection device, the absolute value of y is less than or equal to the vertical distance from the optical axis of the ultra-short focus lens 401 to the upper surface of the laser projection device, or less than or equal to the vertical distance from the optical axis of the ultra-short focus lens 401 to the lower surface of the laser projection device, and the absolute value of z is less than or equal to the depth of the laser projection device.

[0064] In some embodiments, the vertical distance between the imaging camera 402 and the first plane YOZ is less than or equal to 11 / 12 of the half width of the laser projection device.

[0065] In one implementation scenario, when the number of the imaging camera 402 is one, the imaging camera 402 is located on the second coordinate axis Z axis, that is, x=0, the offset is 0, which is less than 11 / 12 of the half width of the laser projection device. At this time, the imaging camera 402 is centered in the width direction, that is, the X direction. For details, please refer to the position of the imaging camera 402 shown in Figure 6.

[0066] At this time, the specific positions of the single imaging camera 402 and the laser projection device can be referred to as shown in Figures 9 to 11, wherein Figure 9 is a side view of a laser projection device provided in an embodiment of the present application, Figure 10 is a top view 1 of a laser projection device provided in an embodiment of the present application, and Figure 11 is a top view 2 of a laser projection device provided in an embodiment of the present application.

[0067] In another implementation scenario, still using a single imaging camera 402 as an example, when imaging camera 402 has a certain offset in the width direction, please refer to Figure 8 for details. Figure 8 is a second schematic diagram of the positional relationship between the imaging camera and the projection screen provided in an embodiment of the present application. In this case, x, y, and z of imaging camera 402 are all non-zero. The absolute value of x is the perpendicular distance between imaging camera 402 and first plane YOZ, which can represent the offset of imaging camera 402 in the width direction. As long as the absolute value of x is less than or equal to 11 / 12 of the half-width of the laser projection device, its specific value can be set according to actual needs.

[0068] For a single imaging camera 402, the center of the imaging range of the imaging camera 402 may or may not coincide with the center point O' of the projection image. The center of the imaging range is the intersection of the optical axis of the imaging camera 402 and the display image, as shown below:

[0069] In one implementation scenario, if the intersection of the optical axis of the imaging camera 402 and the display screen coincides with the center point O' of the projection screen, its capture range is symmetrical in width and height, i.e., X'left = X'right and Y'up = Y'down. In this case, the specific position of the imaging camera 402 is not limited. Here, X'left and X'right represent the distances from the projection screen to the two sides of the imaging camera 402's capture range in the direction corresponding to the X axis, and Y'up and Y'down represent the distances from the projection screen to the two sides of the imaging camera 402's capture range in the direction corresponding to the Y axis.

[0070] In another implementation scenario, if the intersection of the optical axis of the camera 402 and the display screen does not coincide with the center point O' of the projection screen, the shooting range is asymmetric in width and height, and X'left≠X'right and / or Y'up≠Y'down.

[0071] As shown in Figures 6 and 8 , when a single imaging camera 402 is offset in the width direction and its Y'up, Y'down, X'left, and X'right are different, the intersection of the optical axis L-op of the imaging camera 402 and the projected image is also offset and no longer coincides with the center point O' of the projected image. This means that the center of the imaging camera 402's shooting range is separated from the center point O' of the projected image, ensuring that the imaging camera 402 meets the required shooting range in both the width and height directions. If the imaging camera 402's field of view, i.e., its shooting range, is sufficiently large and the width and left and right shooting ranges are not required to be identical, then the intersection of the optical axis L-op of the imaging camera 402 and the projected image can satisfy the required shooting range without being required to offset or coincide with the center point O' of the projected image.

[0072] In some embodiments, when there are multiple imaging cameras 402 , the shooting ranges of the multiple imaging cameras 402 are the same in size, or the shooting ranges of the multiple imaging cameras 402 are different in size.

[0073] In one implementation scenario, when the shooting ranges of multiple imaging cameras 402 are the same size, the multiple imaging cameras 402 evenly shoot the entire area or consider a certain overlapping area. The entire area is the sum of the shooting ranges of the multiple imaging cameras 402, and the overlapping area is only calculated once.

[0074] Taking two imaging cameras 402 as an example, Figure 12 is a third schematic diagram of the positional relationship between an imaging camera and a projection screen provided in an embodiment of the present application. The coordinates of the two imaging cameras 402 are (x1, y1, z1) and (x2, y2, z2), respectively, where the absolute value of x1 and the absolute value of x2 may be equal or unequal. Similarly, the absolute value of y1 and the absolute value of y2 may be equal or unequal, and the absolute value of z1 and the absolute value of z2 may be equal or unequal.

[0075] In one implementation scenario, the multiple imaging cameras 402 are arranged symmetrically along the optical axis of the ultra-short focus lens 401, or the multiple imaging cameras 402 are arranged asymmetrically along the optical axis of the ultra-short focus lens; wherein the direction corresponding to the optical axis of the ultra-short focus lens 401 is consistent with the second coordinate axis Z axis.

[0076] In one implementation scenario, when multiple imaging cameras 402 are arranged symmetrically along the optical axis of the ultra-short focus lens 401, two imaging cameras 402 are taken as an example, whose coordinates are (x1, y1, z1) and (x2, y2, z2) respectively. When x1 = -x2, y1 = y2, z1 = z2, the two imaging cameras 402 are symmetrical along the optical axis of the ultra-short focus lens 401.

[0077] In one implementation scenario, when the laser projection device includes three imaging cameras 402 , one of them can be located on the optical axis of the ultra-short focus lens 401 , and the remaining two imaging cameras 402 can be arranged symmetrically along the optical axis of the ultra-short focus lens 401 .

[0078] The positional relationship between the three imaging cameras 402 and the laser projection device can be referred to as shown in Figures 13 to 15, wherein Figure 13 is a top view three of a laser projection device provided in an embodiment of the present application, Figure 14 is a top view four of a laser projection device provided in an embodiment of the present application, and Figure 15 is a top view five of a laser projection device provided in an embodiment of the present application.

[0079] In another implementation scenario, when the positions of multiple imaging cameras 402 are arranged asymmetrically along the optical axis of the ultra-short focus lens 401, it is only necessary to meet the requirements that the vertical distance between each imaging camera 402 and the first plane YOZ is less than or equal to 11 / 12 of the half width of the laser projection device, and the vertical distance to the second plane XOZ is less than or equal to the vertical distance from the optical axis of the ultra-short focus lens 401 to the upper surface of the laser projection device, and the vertical distance to the third plane XOY is less than or equal to the depth of the laser projection device.

[0080] In one implementation scenario, after N imaging cameras 402 capture images including the projection picture and the projection screen, the processor can obtain the above images and determine the positional relationship between the projection picture and the projection screen based on the above images, further adjust the position of the laser projection device or correct the projection picture so that the projection picture can be displayed on the projection screen, thereby achieving automatic screen entry.

[0081] When calibrating the projected image, automatic calibration of the projected image can be achieved based on relevant software. In one implementation scenario, when calibrating the projected image, the horizontal and vertical positions of the projected image on the projection screen can be adjusted to center or align the projected image, and / or the size of the projected image can be adjusted to fit the size of the projection screen, and / or the shape, rotation angle, trapezoidal shape, and edges of the image can be adjusted to achieve a better display effect on the projection screen.

[0082] In one implementation scenario, the processor can also determine the clarity of the current projected image based on the image. If the ultra-short-throw lens 401 experiences temperature drift, causing some or all areas of the projected image to appear blurred and out of focus, resulting in reduced clarity, the processor can adjust the focus of the ultra-short-throw lens 401 to improve the clarity of the projected image and enhance the display quality.

[0083] The present application provides a laser projection device, including an ultra-short focus lens 401 and N imaging cameras 402, where N is a natural number greater than or equal to 1. The ultra-short focus lens 401 includes a reflector 4011, which can reflect the image beam onto the projection screen to display the projection picture on the projection screen. For any imaging camera 402, the vertical distance between the imaging camera 402 and the first plane YOZ is less than or equal to the half-width of the laser projection device, the vertical distance between the imaging camera 402 and the second plane XOZ is less than or equal to the vertical distance between the optical axis of the ultra-short focus lens 401 and the upper surface of the laser projection device, and the vertical distance between the imaging camera 402 and the third plane XOY is less than or equal to the depth of the laser projection device. Since the N imaging cameras 402 included in the laser projection device can capture images including the projection picture and the projection screen, the captured images can be used to adjust the position of the laser projection device, and the projection picture can also be automatically corrected by software, thereby achieving automatic screen entry without the user having to manually adjust the position of the laser projection device, thereby improving the user experience. At the same time, based on the captured images, automatic correction can be performed when the laser projection equipment has temperature drift, so that the projection picture maintains a high degree of clarity and ensures the display effect of the projection picture.

[0084] In one or more embodiments of the present application, to achieve automatic screen entry, the shooting range of the imaging camera 402 needs to be larger than the size of the projection screen. Specifically, in one implementation scenario, the sum of the shooting ranges of the N imaging cameras 402 exceeds the width of the projection screen by a first width unilateral dimension and a second width unilateral dimension that are both greater than or equal to 3 mm.

[0085] Wherein, based on the direction corresponding to the third coordinate axis X, the first width unilateral dimension is the distance between one side edge of the sum of the shooting ranges of the N imaging cameras 402 and the projection screen;

[0086] The second width single-side dimension is the distance between the other side edge of the sum of the shooting ranges of the N imaging cameras 402 and the projection screen.

[0087] In one implementation scenario, when N is 1 and the number of imaging cameras 402 is one, the sum of the shooting ranges of the N imaging cameras 402 is the shooting range of the imaging camera 402. At this time, the shooting range of the imaging camera 402 exceeds the first width unilateral dimension and the second width unilateral dimension of the projection screen width, both of which are greater than or equal to 3 mm.

[0088] In another implementation scenario, when N is a natural number greater than 1, that is, the number of imaging cameras 402 is multiple, then the sum of the shooting ranges of the multiple imaging cameras 402 exceeds the first width unilateral dimension and the second width unilateral dimension of the projection screen width, both of which are greater than or equal to 3 mm.

[0089] The third coordinate axis, X, corresponds to the width of the laser projection device. Still referring to FIG6 , the direction corresponding to the third coordinate axis, X, is the left-right direction shown in FIG6 . The first width dimension, X'left, is shown in FIG6 , representing the distance between the left edge P1 of the imaging camera 402's imaging range and the left edge P2 of the projection screen. The second width dimension, X'right, is shown in FIG6 , representing the distance between the right edge P4 of the imaging camera 402's imaging range and the right edge P3 of the projection screen.

[0090] It should be noted that the first width single-side dimension X'left and the second width single-side dimension X'right may be the same or different and may be set according to actual needs, which is not limited in this application.

[0091] For example, let's take any imaging camera 402 as an example. The placement of imaging camera 402 is (x, y, z). In one implementation scenario, when x = 0, meaning that imaging camera 402 is on the Z axis, the distance from the intersection of the optical axis L-op of imaging camera 402 and the projected image to the center of the projected image in the X' direction is 0, and the first width dimension X'left and the second width dimension X'right are equal. The intersection of the optical axis L-op of imaging camera 402 and the projected image is the center of the imaging range of imaging camera 402.

[0092] In another implementation scenario, when x>0, that is, in the width direction, the imaging camera 402 is offset to the right. At this time, the intersection of the optical axis L-op of the imaging camera 402 and the projection screen is also offset and located to the right of the center point of the projection screen. The first width unilateral dimension X'left is smaller than the second width unilateral dimension X'right.

[0093] Similarly, in another implementation scenario, when x is less than 0, that is, in the width direction, the imaging camera 402 is offset to the left. At this time, the intersection of the optical axis L-op of the imaging camera 402 and the projection screen is also offset and is located to the left of the center point of the projection screen. The first width unilateral dimension X'left is greater than the second width unilateral dimension X'right.

[0094] In some embodiments, the sum of the shooting ranges of the N imaging cameras 402, the first unilateral dimension and the second unilateral dimension of the height exceeding the height of the projection screen are both greater than or equal to 3 mm;

[0095] Wherein, based on the direction corresponding to the first coordinate axis Y axis, the first height unilateral dimension is the distance between one side edge of the sum of the shooting ranges of the N imaging cameras 402 and the projection screen;

[0096] The second height single-side dimension is the distance between the other side edge of the sum of the shooting ranges of the N imaging cameras 402 and the projection screen.

[0097] In one implementation scenario, when N is 1, that is, the number of imaging cameras 402 is one, the sum of the shooting ranges of the N imaging cameras 402 is the shooting range of the imaging camera 402, and the shooting range of the imaging camera 402 exceeds the first height unilateral dimension and the second height unilateral dimension of the projection screen height, both of which are greater than or equal to 3 mm.

[0098] Still referring to FIG6 , the direction corresponding to the first coordinate axis Y is the up-down direction. The first height dimension is Y'up shown in FIG6 , which represents the distance between the upper edge Q1 of the imaging camera 402's shooting range and the upper edge Q2 of the projection screen. The second height dimension is Y'down shown in FIG6 , which represents the distance between the lower edge Q4 of the imaging camera 402 and the lower edge Q3 of the projection screen.

[0099] Among them, the first height unilateral size and the second height unilateral size can be the same or different, and can be set according to actual needs. This application does not limit this.

[0100] It should be noted that if only the low clarity of the projection image caused by temperature drift needs to be solved, the shooting range of the imaging camera 402 can be equal to or greater than the size of the projection screen, and there is no limitation on the first width unilateral size, the second width unilateral size, the first height unilateral size and the second height unilateral size.

[0101] In some embodiments, the N imaging cameras 402 are placed at a certain tilt angle to the second plane XOZ, where the tilt angle is the angle between the optical axis of the imaging camera 402 and the second plane XOZ.

[0102] In one implementation scenario, when N is a natural number greater than 1, that is, when there are multiple imaging cameras 402, each imaging camera 402 needs to determine a corresponding tilt angle, and the tilt angles corresponding to different imaging cameras 402 can be the same or different.

[0103] For example, let's use any imaging camera 402 as an example, as shown in FIG6 . The tilt angle of imaging camera 402 is θcam, as shown in FIG6 . As the tilt angle increases, the imaging range shifts upward. As the tilt angle decreases, the imaging range shifts downward. Therefore, the tilt angle changes the position of the intersection point between the optical axis of imaging camera 402 and the projected image in the height direction (i.e., the Y' direction), and also affects the first and second height unilateral dimensions.

[0104] In one implementation scenario, when the imaging camera 402 is placed at a certain tilt angle, the intersection of the optical axis of the imaging camera 402 and the projection screen is at the same height as the center point of the projection screen. This tilt angle is recorded as the target tilt angle. At this time, the first height unilateral size and the second height unilateral size are equal.

[0105] In another implementation scenario, when the tilt angle of the imaging camera 402 is greater than the target tilt angle, the shooting range moves upward, and the intersection of the optical axis of the imaging camera 402 and the projection screen is higher than the center point of the projection screen in the Y' direction, and the first height unilateral dimension is greater than the second height unilateral dimension.

[0106] In another implementation scenario, when the tilt angle of the imaging camera 402 is smaller than the target tilt angle, the shooting range moves downward, and the intersection of the optical axis of the imaging camera 402 and the projection screen is lower than the center point of the projection screen in the Y' direction, and the first height unilateral dimension is smaller than the second height unilateral dimension.

[0107] Still taking a single imaging camera 402 as an example, in one implementation scenario, when the single imaging camera 402 is located on the second coordinate axis Z-axis, still referring to FIG. 6 , the optical axis L-op of the imaging camera 402 intersects the projection image at the center point O' of the projection image, and the tilt angle is θcam as shown in FIG. 6 . Preferably, the shooting range of the imaging camera 402, i.e., the field of view coverage range, coincides with the center point O' of the projection image. In this case, a method for calculating the tilt angle θcam is as follows:

[0108] θcam=180*atan(H1 / D1) / PI() (1)

[0109] Among them, H1=(Y'up-Y'down+H-scr) / 2+H-scr*(offset-1) / 2-y+Y'down (2)

[0110] Or, H1=(Y'up+Y'down) / 2+H-scr / 2+H-scr*(offset-1) / 2-y (3)

[0111] D1=W-scr*TR+z (4)

[0112] In the above formula, θcam represents the tilt angle of the imaging camera 402, that is, the angle between the optical axis of the imaging camera 402 and the second plane XOZ, D1 is the vertical distance from the imaging camera 402 to the projection screen in the direction of the second coordinate axis Z-axis, PI() represents π, Y'up is the unilateral dimension of the first height, which is positive, Y'down is the unilateral dimension of the second height, which is negative, H-scr is the height of the projection screen, which is positive, offset is the vertical distance from the center of the projection screen to the second plane XOZ / half the height of the projection screen, W-scr is the width of the projection screen, which is positive, TR is the projection ratio, y and z are the coordinates of the imaging camera 402, considering their positive and negative in the OXYZ coordinate system, H1 is the vertical distance between the center point O' of the projection screen and the plane parallel to the second plane XOZ where the imaging camera 402 is located in the direction of the first coordinate axis Y-axis. Since the intersection of the optical axis L-op of the imaging camera 402 and the projection screen is the center point O' of the projection screen at this time, H1 can also represent the vertical distance between the intersection of the optical axis L-op of the imaging camera 402 and the projection screen to the plane parallel to the second plane XOZ where the imaging camera 402 is located.

[0113] At this time, the calculation formula of the half field of view angle of the imaging camera 402 in each direction can be referred to as shown below:

[0114] θx1=180*atan(Wcam / 2 / DL-op) / PI() (5)

[0115] θy1=180*atan(Hcam / 2 / DL-op) / PI() (6)

[0116] θimg=180*atan(sqrt((Hcam / 2)^2+(Wcam / 2)^2) / DL-op) / PI() (7)

[0117] DL-op=sqrt(D1^2+H1^2) (8)

[0118] Hcam / 2=projection screen height / 2+(Y'up-Y'down) / 2 (9)

[0119] Wcam / 2=projection image width / 2+(X'right-X'left) / 2 (10)

[0120] Among them, θx1 represents the half field of view angle of the imaging camera 402 in the width direction, θy1 represents the half field of view angle of the imaging camera 402 in the height direction, θimg represents the half field of view angle of the imaging camera 402 in the diagonal direction, Hcam / 2 represents the half height of the shooting range of the imaging camera 402, Wcam / 2 represents the half width of the shooting range of the imaging camera 402, Y'up is the first height unilateral dimension, which is positive, Y'down is the second height unilateral dimension, which is negative, X'left is the first width unilateral dimension, which is negative, X'right is the second width unilateral dimension, which is positive, DL-op is the distance between the intersection of the optical axis L-op of the imaging camera 402 and the projection screen and the imaging camera 402, D1 is the vertical distance from the imaging camera 402 to the projection screen, H1 is the vertical distance between the center point O' of the projection screen and the plane parallel to the second plane XOZ where the imaging camera 402 is located based on the first coordinate axis Y-axis direction, and PI() represents π.

[0121] In another implementation scenario, when a single imaging camera 402 is not placed at the target tilt angle and is not located on the second coordinate axis Z-axis, that is, the imaging camera 402 has a certain offset in the direction of the third coordinate axis X-axis, as shown in Figure 8, at this time, the intersection of the optical axis L-op of the imaging camera 402 and the projection screen is W1, which does not coincide with the center point O' of the projection screen.

[0122] At this time, in the direction of the first coordinate axis Y, the vertical distance between the intersection of the optical axis L-op of the imaging camera 402 and the projection image and the plane parallel to the second plane XOZ where the imaging camera 402 is located is H1' shown in FIG8. One way to calculate H1' is as follows:

[0123] H1'=sqrt(H1^2+(x-(X'right-X'left) / 2)^2) (11)

[0124] Among them, H1 is the vertical distance between the center point O' of the projection image and the plane parallel to the second plane XOZ where the imaging camera 402 is located based on the direction corresponding to the first coordinate axis Y axis, x is a coordinate value of the imaging camera, X'left is the unilateral size of the first width, which is negative, and X'right is the unilateral size of the second width, which is positive.

[0125] At this time, the distance DL-op′ between the intersection of the optical axis L-op of the imaging camera 402 and the projection image and the imaging camera 402 is calculated as follows:

[0126] DL-op'=sqrt(D1'^2+H1'^2) (12)

[0127] Among them, D1' is the vertical distance from the imaging camera 402 to the projection screen in the direction of the second coordinate axis Z axis, and H1' is the vertical distance between the intersection of the optical axis L-op of the imaging camera 402 and the projection screen and the plane parallel to the second plane XOZ where the imaging camera 402 is located in the direction of the first coordinate axis Y axis.

[0128] When the intersection of the optical axis L-op of the imaging camera 402 and the projection screen does not coincide with the center point of the projection screen, based on the above formulas 11 and 12, determine the vertical distance H1' between the intersection of the optical axis L-op of the imaging camera 402 and the projection screen to the plane parallel to the second plane XOZ where the imaging camera 402 is located, and the distance DL-op' between the intersection of the optical axis L-op of the imaging camera 402 and the projection screen to the imaging camera 402. Then, refer to the above formulas 1-10 to determine the field of view angle of the imaging camera 402 in various directions and the tilt angle of its placement at this time.

[0129] When there are multiple imaging cameras 402, the calculation principles of the field of view angles of each imaging camera 402 in the width, height and diagonal directions, as well as the tilt angles of each imaging camera 402 are basically the same as the calculation principles of the above-mentioned single imaging camera 402. Please refer to the above and will not be repeated here.

[0130] It should be noted that the center of the sum of the shooting ranges of the N imaging cameras 402 may or may not coincide with the center point of the projection screen. It only needs to satisfy that the sum of the shooting ranges of the N imaging cameras 402 is larger than the size of the projection screen, and the first width unilateral dimension and the second width unilateral dimension exceeding the width of the projection screen are both greater than or equal to 3mm, and the first height unilateral dimension and the second height unilateral dimension exceeding the height of the projection screen are both greater than or equal to 3mm.

[0131] In summary, the sum of the shooting ranges of the N imaging cameras 402, the first width unilateral dimension and the second width unilateral dimension exceeding the width of the projection screen are both greater than or equal to 3 mm, and the first height unilateral dimension and the second height unilateral dimension exceeding the height of the projection screen are both greater than or equal to 3 mm, so that the sum of the shooting ranges of the N imaging cameras 402 meets the requirements of automatic screen entry, thereby realizing automatic screen entry.

[0132] The present application also provides a laser projection image display method, which can be specifically referred to in FIG16 , which is a flow chart of a laser projection image display method provided in an embodiment of the present application.

[0133] It should be noted that the method is applied to the laser projection device described in the above embodiment, and the laser projection device includes: an ultra-short focus lens and N imaging cameras.

[0134] The ultra-short-throw lens includes a reflector for reflecting an image beam to display a projection image on a projection screen.

[0135] The vertical distance between the imaging camera and the first plane is less than or equal to the half width of the laser projection device, the vertical distance between the imaging camera and the second plane is less than or equal to the vertical distance between the optical axis of the ultra-short focus lens and the upper surface of the laser projection device, and the vertical distance between the imaging camera and the third plane is less than or equal to the depth of the laser projection device; wherein N is a natural number greater than or equal to 1.

[0136] The first plane is the plane formed by the first coordinate axis and the second coordinate axis, the second plane is the plane formed by the third coordinate axis and the second coordinate axis, and the third plane is the plane formed by the third coordinate axis and the first coordinate axis;

[0137] The intersection of the first coordinate axis, the second coordinate axis and the third coordinate axis is the intersection of the optical axis of the ultra-short focus lens and the reflector. The first coordinate axis, the second coordinate axis and the third coordinate axis are respectively consistent with the directions corresponding to the height, depth and width of the laser projection device. The upper surface is the surface of the laser projection device that is parallel to the second plane and away from the second plane.

[0138] As shown in FIG16 , the laser projection image display method may include the following steps:

[0139] S1601. Acquire images captured by N imaging cameras, where the images include a projection image and a projection screen.

[0140] In the present application, when the projected image is corrected, a feature map card can be projected and displayed on the projection screen. The projected feature map card can be shown in FIG17 , which is a schematic diagram of a feature map card provided in an embodiment of the present application.

[0141] It should be noted that the embodiment of the present application is only illustrated by taking the feature map card shown in FIG17 as a checkerboard as an example, and does not constitute any limitation.

[0142] For example, when the projection host projects a feature card on the projection screen, it can send instructions to N imaging cameras installed on the projection device. The N imaging cameras can photograph the projection screen in response to the instructions and send the captured images to the projection host, so that the projection host can obtain the images captured by the N imaging cameras.

[0143] It should be understood that the number of captured images corresponds to the number of imaging cameras. When the number of imaging cameras is one, the number of captured images is one. When the number of imaging cameras is two, the number of captured images is two. When the number of imaging cameras is multiple, the number of captured images is multiple.

[0144] In one possible implementation, the images captured by multiple imaging cameras together form an image that includes the entire feature map card and projection screen. For example, when there are two imaging cameras, the image captured by each imaging camera is half of the feature map card and projection screen.

[0145] The sum of the shooting ranges of the N imaging cameras is greater than the size of the projection screen. Specifically, the sum of the shooting ranges of the N imaging cameras has a first width and a second width that exceed the width of the projection screen by greater than or equal to 3 mm. The sum of the shooting ranges of the N imaging cameras can be seen in Figure 18, which is a schematic diagram of the shooting range of an imaging camera provided in an embodiment of the present application.

[0146] For example, after the image is acquired, the image may be processed. Specifically, the image may be subjected to denoising, contrast enhancement, and other processing to highlight the edge of the screen.

[0147] S1602: Determine the positional relationship between the projection image and the projection screen based on the image.

[0148] The positional relationship between the projection image and the projection screen includes a positional deviation parameter of the projection image.

[0149] For example, the positional relationship between the current projection image and the projection screen, i.e., the position deviation parameter of the projection image, can be determined based on the position of the feature points of the feature card in the image and the position of the feature points when the projection image is not offset or distorted.

[0150] S1603: Adjust the position of the laser projection device and / or correct the projected image according to the positional relationship.

[0151] In the present application, adjusting the position of the laser projection device according to the positional relationship may include determining a position adjustment parameter of the laser projection device according to the positional relationship; and adjusting the position of the laser projection device according to the position adjustment parameter to center or align the projection screen.

[0152] Exemplarily, the position deviation parameters of the projection screen can be converted into position adjustment parameters of the laser projection device. For example, when the projection screen is offset to the left, the parameters for the laser projection device to move to the right can be determined so that the laser projection device can move to the right to adjust the projection screen to a centered position.

[0153] In this way, by adjusting the position of the laser projection device, the projected image can be adjusted to be aligned with the center of the projection screen, thereby improving the display effect of the projected image.

[0154] In the present application, correcting the projection image according to the positional relationship may include determining correction parameters according to the positional relationship; adjusting the horizontal and vertical positions of the projection image on the projection screen according to the correction parameters, and / or adjusting the size of the projection image, and / or adjusting the image shape, rotation angle, trapezoidal shape and image edges to center or align the projection image.

[0155] In this way, through internal correction, the projected image is adjusted to be aligned with the center of the projection screen, thereby improving the display effect of the projected image.

[0156] It is understood that when it is necessary to calibrate both the position of the laser projector and the projected image simultaneously, the position of the laser projector can be calibrated first, followed by the projected image. In this case, after calibrating the position of the laser projector, it is necessary to re-project the display feature card, capture a new image using the imaging camera, determine the new positional relationship based on the new image, and calibrate the projected image based on the new position.

[0157] Therefore, the projection display method provided in the present application can correct the position of the laser projection device and / or the projection screen according to the image captured by the imaging camera, thereby improving the projection display effect.

[0158] In the present application, the entire process of correcting the projection image can be seen in FIG19 , which is a flow chart of a method for correcting a projection image provided in an embodiment of the present application.

[0159] As shown in FIG19 , the method for correcting the projection image may include the following steps:

[0160] S1901: System initialization.

[0161] When entering the projection image calibration process, the system is first initialized. System initialization includes starting the imaging camera, loading the parameters of the projection device, and setting the default projection area.

[0162] S1902: Project and display a feature image card to obtain a first image captured by an imaging camera.

[0163] According to the default projection area, the feature card is projected and displayed, and the feature card may be as shown in Figure 17. The first image captured by the imaging camera can be seen from the above embodiment, which will not be described here.

[0164] S1903: Process the first image to obtain a second image.

[0165] The first image is processed by denoising, contrast enhancement, etc. to obtain a processed second image to highlight the edge of the projection screen to facilitate subsequent edge detection.

[0166] S1904: Perform edge detection on the second image to determine a target area that needs to be adjusted.

[0167] Using an edge detection algorithm and a Hough transform, straight line edges are detected, vertices of the projection screen are identified, and positions of the vertices of the projection screen in the second image are determined.

[0168] When there is only one imaging camera, the positions of the four vertices of the projection screen can be determined. Furthermore, by comparing the positions of the four vertices of the projection screen in the second image and the actual positions of the four vertices of the projection screen, the projection area that needs to be adjusted can be determined.

[0169] When there are two imaging cameras, the positions of the vertices of the projection screen contained in each image can be determined. Furthermore, by comparing the positions of the vertices of the projection screen contained in each image and the actual positions of the vertices of the projection screen, it is determined that the projection area needs to be adjusted.

[0170] S1905: Determine the perspective transformation matrix.

[0171] Exemplarily, the positions of the four vertices of the projection screen may be determined, and the corresponding perspective transformation matrix may be determined based on the positions of the four vertices of the projection screen in practice.

[0172] S1906: Determine correction parameters according to the perspective transformation matrix and the positions of the feature points in the second image.

[0173] The feature points in the second image are feature points in the feature map card. The above method for determining the positions of the vertices of the projection screen in the second image can be used to determine the positions of the feature points in the second image.

[0174] According to the position of the feature point in the target area and the perspective transformation matrix, the position to be adjusted can be determined to determine the correction parameter, that is, the position deviation parameter.

[0175] It should be noted that the above-mentioned positions can all be expressed by coordinates, so the position deviation parameter can also be a coordinate deviation parameter.

[0176] S1907: Correct the projected image according to the correction parameters.

[0177] The laser projection device can obtain the pixel value of the image to be projected, and map each pixel of the image to be projected to a corresponding position according to the deviation parameter to display the image to be projected, so as to realize the correction of the projection picture.

[0178] Pixel values ​​contain visual information such as image color, brightness, texture, etc.

[0179] S1908: Whether the calibration result meets the requirements.

[0180] In the embodiment of the present application, the correction result after correction, that is, the projection image, can be verified to determine whether the correction effect meets the requirements.

[0181] When correcting the correction result, the feature map card can be re-projected, a new image can be collected by the imaging camera, and the edge alignment error can be determined based on the new image. When the edge alignment error is less than the preset value, the deviation parameter can be saved and the correction process can be exited; when the edge alignment error is greater than or equal to the preset value, the above steps S1902-1907 can be re-executed until the edge alignment error is less than the preset value.

[0182] In this way, the projection display effect of the laser projection device can be improved by using the imaging camera in the laser projection device to correct the projection image.

[0183] In the present application, when the image clarity of the laser projection device is reduced due to the temperature drift phenomenon, the imaging camera can be used to automatically perform temperature drift correction, as shown in Figure 20, which is a flow chart of a temperature drift correction provided in an embodiment of the present application.

[0184] As shown in FIG20 , the process of performing temperature drift correction on a laser projection device may include the following steps:

[0185] S2001. System initialization.

[0186] When entering the temperature drift correction process, the system is initialized first. The system initialization includes starting the imaging camera, loading the parameters of the projection device, and setting the default projection area.

[0187] S2002: Project and display the focus card to obtain a third image captured by the imaging camera.

[0188] A focus chart is a chart that contains crosshairs or other clear focus markings.

[0189] According to the default projection area, the focus card is projected and displayed. The focus card can be shown in Figure 21, which is a schematic diagram of a focus card provided in an embodiment of the present application.

[0190] S2003 : Determine the intensity value of a single pixel line in the third image, and obtain line width values ​​corresponding to the positions of two pixel points whose intensity values ​​drop to a preset intensity.

[0191] Taking the focus chart shown in FIG21 as an example, the crosshairs in the focus chart can be determined using an edge detection algorithm or template matching. For a single pixel line (horizontal or vertical line) of the crosshairs, the intensity value of each pixel point in the single pixel line is obtained.

[0192] The preset intensity is a value less than the peak intensity, which may be 25% or 20% of the peak intensity, and is not limited in this embodiment of the present application.

[0193] For example, if the preset intensity is 20% of the peak intensity, after obtaining the intensity values ​​of each pixel in a single pixel line, an intensity distribution curve can be drawn. In the intensity distribution curve, search from the peak intensity position to both sides to determine the position where the intensity drops to 20% of the peak intensity. The distance between the two positions where the intensity drops to 20% is determined as the line width value.

[0194] S2004: When the line width value is greater than the preset line width value, perform temperature drift correction on the projected image.

[0195] The preset line width value can be set based on the actual situation of the laser projection device, and the embodiment of the present application does not limit this.

[0196] When the line width value is greater than the preset line width value, the automatic focus program of the lens can be started to perform temperature drift correction on the projected image.

[0197] There are two possible implementations for temperature drift correction of the projected image:

[0198] In one possible implementation, the focus adjustment step corresponding to the current line width value may be determined according to a predetermined correspondence between the line width value and the focus adjustment step, and focusing may be performed according to the focus adjustment step.

[0199] After focusing, the process may return to steps S2002 - S2004 until the obtained line width value is less than or equal to the preset line width value.

[0200] Another possible implementation is to perform single-step adjustment. Each time a step is adjusted, the process returns to execute steps S2002 to S2004 until the obtained line width value is less than or equal to the preset line width value.

[0201] In this way, when the laser projection device experiences temperature drift, the laser projection device can automatically perform temperature drift correction based on the captured image to maintain a high clarity of the projected image and ensure the display effect of the projected image.

[0202] 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 them. 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0203] For ease of explanation, the above description has been made with reference to specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations are possible. The above embodiments are selected and described to better explain the principles and practical applications, so that those skilled in the art can better utilize the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A laser projection device, comprising: An ultra-short-throw lens includes a reflector for reflecting an image beam to display a projection image on a projection screen; N imaging cameras, wherein a vertical distance between the imaging camera and a first plane is less than or equal to half the width of the laser projection device, a vertical distance between the imaging camera and a second plane is less than or equal to a vertical distance between the optical axis of the ultra-short focus lens and the upper surface of the laser projection device, and a vertical distance between the imaging camera and a third plane is less than or equal to the depth of the laser projection device; the imaging cameras are used to capture an image including a projected image and a projection screen, and the image is used to adjust the position of the laser projection device and / or calibrate the projected image; Wherein, N is a natural number greater than or equal to 1; The first plane is a plane formed by the first coordinate axis and the second coordinate axis, the second plane is a plane formed by the third coordinate axis and the second coordinate axis, and the third plane is a plane formed by the third coordinate axis and the first coordinate axis; The intersection of the first coordinate axis, the second coordinate axis and the third coordinate axis is the intersection of the optical axis of the ultra-short focus lens and the reflector. The first coordinate axis, the second coordinate axis and the third coordinate axis are respectively consistent with the directions corresponding to the height, depth and width of the laser projection device. The upper surface is the surface of the laser projection device that is parallel to the second plane and away from the second plane.

2. The laser projection device according to claim 1, wherein a vertical distance between the imaging camera and the first plane is less than or equal to 11 / 12 of a half width of the laser projection device. 3 . The laser projection device according to claim 1 , wherein the sum of the shooting ranges of the N imaging cameras is greater than the size of the projection screen. 4 . The laser projection device according to claim 1 , wherein the N imaging cameras are placed at a certain tilt angle to the second plane, and the tilt angle is the angle between the optical axis of the imaging camera and the second plane.

5. The laser projection device according to any one of claims 1 to 4, wherein the sum of the shooting ranges of the N imaging cameras, the first width unilateral dimension and the second width unilateral dimension exceeding the width of the projection screen are both greater than or equal to 3 mm; in, Based on the direction corresponding to the third coordinate axis, the first width unilateral dimension is the distance between one side edge of the sum of the shooting ranges of the N imaging cameras and the projection screen; The second width single-side dimension is the distance between the other side edge of the sum of the shooting ranges of the N imaging cameras and the projection screen. 6 . The laser projection device according to claim 1 , wherein the number of the imaging camera is one, and the imaging camera is located on the second coordinate axis. 7 . The laser projection device according to claim 6 , wherein the imaging camera is centered in the direction corresponding to the third coordinate axis.

8. The laser projection device according to claim 1 or 2, wherein the number of the imaging camera is one, and the vertical distance between the imaging camera and the first plane, the vertical distance between the imaging camera and the second plane, and the vertical distance between the imaging camera and the third plane are all greater than 0. 9 . The laser projection device according to claim 8 , wherein the center of the shooting range of the imaging camera coincides with the center point of the projection image. 10 . The laser projection device according to claim 8 , wherein the center of the shooting range of the imaging camera does not coincide with the center point of the projection image.

11. The laser projection device according to claim 1, wherein the number of the imaging cameras is two, the vertical distances between the two imaging cameras and the first plane are equal or unequal, the vertical distances between the two imaging cameras and the second plane are equal or unequal, and the vertical distances between the two imaging cameras and the third plane are equal or unequal. 12 . The laser projection device according to claim 1 , wherein the number of the imaging cameras is multiple, and the shooting ranges of the multiple imaging cameras are the same in size, or the shooting ranges of the multiple imaging cameras are different in size.

13. The laser projection device according to claim 12, wherein the plurality of imaging cameras are symmetrically arranged along the optical axis of the ultra-short focus lens, or the plurality of imaging cameras are asymmetrically arranged along the optical axis of the ultra-short focus lens; in, The direction corresponding to the optical axis of the ultra-short focus lens is consistent with the second coordinate axis. The laser projection device according to claim 1 , wherein a throw ratio of the ultra-short focus lens is less than or equal to 0.

5.

15. A laser projection image display method, applied to a laser projection device, the laser projection device comprising: An ultra-short-throw lens includes a reflector for reflecting an image beam to display a projection image on a projection screen; N imaging cameras, wherein a vertical distance between the imaging camera and a first plane is less than or equal to half the width of the laser projection device, a vertical distance between the imaging camera and a second plane is less than or equal to a vertical distance between the optical axis of the ultra-short focus lens and the upper surface of the laser projection device, and a vertical distance between the imaging camera and a third plane is less than or equal to the depth of the laser projection device; wherein N is a natural number greater than or equal to 1; The first plane is a plane formed by the first coordinate axis and the second coordinate axis, the second plane is a plane formed by the third coordinate axis and the second coordinate axis, and the third plane is a plane formed by the third coordinate axis and the first coordinate axis; The intersection of the first coordinate axis, the second coordinate axis, and the third coordinate axis is the intersection of the optical axis of the ultra-short focus lens and the reflector. The first coordinate axis, the second coordinate axis, and the third coordinate axis are respectively consistent with the directions corresponding to the height, depth, and width of the laser projection device. The upper surface is the surface of the laser projection device that is parallel to the second plane and away from the second plane. The method comprises: Acquire images captured by the N imaging cameras, wherein the images include the projection picture and the projection screen; determining a positional relationship between the projection picture and the projection screen based on the image; The position of the laser projection device is adjusted according to the positional relationship and / or the projection image is corrected.

16. The method according to claim 15, wherein adjusting the position of the laser projection device according to the positional relationship comprises: determining position adjustment parameters of the laser projection device according to the position relationship; According to the position adjustment parameters, the position of the laser projection device is adjusted to center or align the projection image.

17. The method according to claim 15, wherein correcting the projection image according to the positional relationship comprises: determining a correction parameter according to the positional relationship; According to the correction parameters, the horizontal and vertical positions of the projected image on the projection screen are adjusted, and / or the size of the projected image is adjusted, and / or the image shape, rotation angle, trapezoidal shape and image edges are adjusted to center or align the projected image.

18. The method according to claim 15, wherein the sum of the shooting ranges of the N imaging cameras exceeds the projection screen width by a first unilateral dimension and a second unilateral dimension, both of which are greater than or equal to 3 mm; in, Based on the direction corresponding to the third coordinate axis, the first width unilateral dimension is the distance between one side edge of the sum of the shooting ranges of the N imaging cameras and the projection screen; The second width single-side dimension is the distance between the other side edge of the sum of the shooting ranges of the N imaging cameras and the projection screen.

19. According to the method according to any one of claims 15-18, the number of the imaging camera is one, the imaging camera is located on the second coordinate axis, and the imaging camera is centered in the direction corresponding to the third coordinate axis; or the vertical distance between the imaging camera and the first plane, the vertical distance between the imaging camera and the second plane, and the vertical distance between the imaging camera and the third plane are all greater than 0.

20. According to the method according to any one of claims 15-18, the number of the imaging cameras is two, the vertical distances between the two imaging cameras and the first plane are equal or unequal, the vertical distances between the two imaging cameras and the second plane are equal or unequal, and the vertical distances between the two imaging cameras and the third plane are equal or unequal.

Images