Focusing method for projector and projector

Abstract

The present disclosure belongs to the technical field of projectors, and provides a focusing method for a projector and a projector, which can solve the existing problem of an edge area of a projected image being out of focus due to being at a great distance from the center of the projected image, thereby leading the projected image to be blurry. The focusing method for a projector provided by the present disclosure comprises: on the basis of relative position parameters between an optical lens and an imaging plane, acquiring a plurality of focus point groups; identifying an image main subject of a current projected image, and calculating the area proportion of the image main subject in the current projected image; on the basis of the area proportion of the image main subject in the current projected image, selecting one of the plurality of focus point groups as first target focus points; and on the basis of the first target focus points, adjusting the relative position parameters between the optical lens and the imaging plane.

Description

Projector focusing method and projector Technical Field

[0001] The present disclosure belongs to the technical field of projectors, and particularly relates to a focusing method of a projector and a projector. Background Art

[0002] Projection products, commonly referred to as projectors, are devices that project images or videos onto an imaging surface using an optical lens. Projectors typically use distance sensors, cameras, and other technical means to determine the projection distance between the projector's optical lens and the imaging surface. The lens is adjusted for telescoping by a focus motor, resulting in a one-to-one correspondence between the projection distance and the lens's focus position.

[0003] Currently, during projection, the center of the imaging plane is generally used as the focus point, and the distance from the optical lens to the center of the projected image (i.e., the center of the imaging plane) is used as the projection distance. When the projected image is large, the edges of the projected image, due to their distance from the center of the projected image, become out of focus, resulting in a blurry image and significantly reducing the user experience.

[0004] Summary of the Invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a focusing method for a projector and a projector.

[0006] In a first aspect, an embodiment of the present disclosure provides a focusing method for a projector, wherein the projector includes: an optical lens; an imaging plane for displaying a projection image is provided on a light-emitting side of the optical lens; wherein the focusing method for the projector includes:

[0007] Acquiring multiple groups of focus points according to relative position parameters between the optical lens and the imaging plane;

[0008] Identifying a main body of the current projection image and calculating an area ratio of the main body of the current projection image;

[0009] Selecting one of the multiple focus points as a first target focus point according to the area ratio of the image subject in the current projection image;

[0010] According to the first target focus point, the relative position parameters between the optical lens and the imaging plane are adjusted.

[0011] In some embodiments, when the area of ​​the screen body in the projection screen is less than a first preset value, each group includes one of the focus points, and a group of the focus points is selected as the first target focus point, and the first target focus point coincides with the center of the imaging plane.

[0012] In some embodiments, when the area of ​​the screen body in the projection screen is greater than a second preset value, the optical lens is arranged opposite to the center of the imaging plane, each group contains four focus points, and the four focus points in each group are evenly arranged around the center of the imaging plane and are respectively located on the two diagonals of the imaging plane.

[0013] In some embodiments, a group of the focus points are selected as first target focus points, and the four first target focus points are respectively located at 1 / 4 and 3 / 4 positions on two diagonals of the imaging plane.

[0014] In some embodiments, when the area of ​​the screen body in the projection screen is greater than a second preset value, the optical lens is arranged directly opposite the center of the imaging plane, each group contains four focus points, and the four focus points in each group are evenly arranged around the center of the imaging plane and are located on an equifocal distance circle with the center of the imaging plane as the center.

[0015] In some embodiments, a group of the focus points is selected as the first target focus points, and the equifocal distance circle where the four first target focus points are located falls within the imaging plane and is tangent to at least one edge of the imaging plane.

[0016] In some embodiments, the imaging plane has a first center line and a second center line passing through its center and perpendicular to each other; when the area of ​​the screen body in the projection screen is greater than a second preset value, the optical lens is offset along the second center line direction, each group includes two focus points, and the two focus points in each group are evenly arranged around the center of the imaging plane and located on the first center line; or, the optical lens is offset along the first center line direction, each group includes two focus points, and the two focus points in each group are evenly arranged around the center of the imaging plane and located on the second center line.

[0017] In some embodiments, a group of the focus points are selected as the first target focus points, and two of the first target focus points are respectively located at the 1 / 4 and 3 / 4 positions of the first center line, or two of the first target focus points are respectively located at the 1 / 4 and 3 / 4 positions of the second center line.

[0018] In some embodiments, adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point further includes:

[0019] The current projection image is subjected to trapezoidal correction by using an optical correction method and a digital correction method.

[0020] In some embodiments, adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point further includes:

[0021] Identifying a main body of the projection image in the next frame, and calculating an area ratio of the main body of the projection image in the next frame;

[0022] selecting another group of focus points from the plurality of focus points as a second target focus point according to the area ratio of the main body of the picture in the projection picture of the next frame;

[0023] According to the second target focus point, the relative position parameters between the optical lens and the imaging plane are adjusted.

[0024] In some embodiments, adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point further includes:

[0025] Identifying a main body of the projection image of the next frame, and determining a position of the main body of the projection image of the next frame;

[0026] selecting another group of focus points from the plurality of focus points as a second target focus point according to the position of the image subject in the projection image of the next frame;

[0027] According to the second target focus point, the relative position parameters between the optical lens and the imaging plane are adjusted.

[0028] In some embodiments, the distance between the first target focus point and the optical lens is within the focal length range of the optical lens;

[0029] The distance between the second target focus point and the optical lens is within the focal length range of the optical lens.

[0030] In some embodiments, obtaining multiple groups of focus points based on relative position parameters between the optical lens and the imaging plane further includes:

[0031] According to the positions of the optical lens and the imaging plane, a relative position parameter between the optical lens and the imaging plane is obtained.

[0032] In a second aspect, an embodiment of the present disclosure provides a projector, wherein the projector includes: an optical lens, a framing structure, an image recognition structure, a main control unit, and a focusing structure; an imaging plane for displaying a projection image is provided on the light-emitting side of the optical lens;

[0033] The optical lens is configured to project a projection image onto the imaging plane;

[0034] The framing structure is configured to obtain multiple groups of focus points according to relative position parameters between the optical lens and the imaging plane;

[0035] The image recognition structure is configured to identify a main body of the current projection image and calculate an area ratio of the main body of the current projection image;

[0036] The main control unit is configured to select one of the multiple focus points as a first target focus point according to the area ratio of the main body of the picture in the current projection picture;

[0037] The focusing structure is configured to adjust a relative position parameter between the optical lens and the imaging plane according to the first target focus point.

[0038] In some embodiments, the image recognition structure is further configured to identify a main body of the projection image in the next frame, and calculate an area ratio of the main body of the projection image in the next frame;

[0039] The main control unit is further configured to select another group of focus points from the multiple groups as a second target focus point according to the area ratio of the main body of the picture in the projection picture of the next frame;

[0040] The focusing structure is further configured to adjust a relative position parameter between the optical lens and the imaging plane according to the second target focus point.

[0041] In some embodiments, the image recognition structure is further configured to identify a main body of the image in the next frame of the projection image, and determine a position of the main body of the image in the next frame of the projection image;

[0042] The main control unit is further configured to select another group of focus points from the plurality of focus points as a second target focus point according to the position of the image subject in the projection image of the next frame;

[0043] The focusing structure is further configured to adjust a relative position parameter between the optical lens and the imaging plane according to the second target focus point.

[0044] In some embodiments, the projector further comprises: a focus sensor;

[0045] The focus sensor is configured to obtain a relative position parameter between the optical lens and the imaging plane according to the positions of the optical lens and the imaging plane.

[0046] In a third aspect, an embodiment of the present disclosure provides an electronic device, wherein the electronic device includes:

[0047] at least one processor; and

[0048] a memory communicatively connected to the at least one processor; wherein,

[0049] The memory stores one or more computer programs that can be executed by the at least one processor. The one or more computer programs are executed by the at least one processor to enable the at least one processor to perform the focusing method of the projector as provided above.

[0050] In a fourth aspect, an embodiment of the present disclosure provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the focusing method of the projector as provided above. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG1 is a schematic structural diagram of an exemplary projector.

[0052] FIG2 is a schematic diagram of an exemplary focusing process of a projector.

[0053] FIG3 is a flow chart of a focusing method for a projector provided in an embodiment of the present disclosure.

[0054] FIG4 is a schematic diagram of a first focusing method provided by an embodiment of the present disclosure.

[0055] FIG5 is a schematic diagram of a second focusing method provided by an embodiment of the present disclosure.

[0056] FIG6 is a schematic diagram of a third focusing method provided in an embodiment of the present disclosure.

[0057] FIG7 a is a schematic diagram of a fourth focusing method provided in an embodiment of the present disclosure.

[0058] FIG7 b is a schematic diagram of the focusing method shown in FIG7 a when the optical lens is offset.

[0059] FIG8 a is a schematic diagram of a fifth focusing method provided by an embodiment of the present disclosure.

[0060] FIG8 b is a schematic diagram of the focusing method shown in FIG8 a when the optical lens is offset.

[0061] FIG9 is a flow chart of another projector focusing method provided by an embodiment of the present disclosure.

[0062] FIG10 is a flow chart of another method for focusing a projector provided in an embodiment of the present disclosure.

[0063] FIG11 is a flow chart of another projector focusing method provided in an embodiment of the present disclosure.

[0064] FIG12 is a schematic diagram of a focusing method provided in an embodiment of the present disclosure.

[0065] FIG13 a is a schematic diagram of a focal length range of a projector.

[0066] FIG13 b is a schematic diagram of the focus point distribution of a projector.

[0067] FIG14 is a schematic diagram of the structure of a projector provided by an embodiment of the present disclosure.

[0068] FIG15 is a schematic structural diagram of an electronic device provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0069] In order to enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0070] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by people with ordinary skills in the field to which this disclosure belongs. The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "an" or "the" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0071] FIG1 is a schematic diagram of the structure of an exemplary projector. As shown in FIG1 , the projector includes: an optical lens 101, a main control unit 102, a focusing structure 103, a focus sensor 104, and a limit sensor 105. An imaging plane 20 for displaying a projection image is provided on the light-emitting side of the optical lens 101; the optical lens 101 is configured to project the projection image onto the imaging plane. The imaging plane can be a screen, or a flat wall, glass, or other plane on which the projection image can be displayed. In the subsequent description of this disclosure, the imaging plane 20 will be taken as an example of a screen.

[0072] The optical lens 101 can form a projection image and project the projection image onto the imaging plane 20 for display, so that the user can view the projection image on the imaging plane 20 with a larger display area.

[0073] The main control unit 102 may include a processor, a storage unit, a power supply and a driving circuit part (not specifically shown in the figure), which can process various information (such as the projection distance and projection angle transmitted by the focus sensor 105), complete the relevant focus parameter calculation, and control the focusing structure 103 to complete the automatic focusing function.

[0074] The focusing structure 103 may include: a motor and a transmission system (not specifically shown in the figure), the motor is generally a stepping motor, and the transmission system can be selected from gear transmission, belt transmission, worm transmission, etc., and the type of motor and transmission system is not limited; the electrode can drive the optical lens 101 through the transmission system to perform telescopic, transmission and other azimuth adjustments to achieve focusing and focal length adjustment of the optical lens 101.

[0075] The focus sensor 104 can be a time of flight (ToF) sensor or a camera. High-end models can also use both a ToF sensor and a camera, or a laser ranging sensor, etc. Its main purpose is to obtain the projection distance, that is, the distance between the optical lens 101 and the imaging plane 20.

[0076] The limit sensor 105 may be an optical coupler, and its purpose is to limit the focus adjustment structure 103. Since the motor used by the focus adjustment structure 103 is generally an open-loop structure, the focus adjustment structure 103 needs to be initialized and calibrated.

[0077] FIG2 is a schematic diagram of an exemplary projector focusing process. As shown in FIG2 , during the projection display process, in order to ensure that the projected image can be directly projected onto the imaging plane 20 and the center of the projected image is relatively clear, the center of the imaging plane 20 is generally used as the focus point M. There is only one focus point M, and the distance from the optical lens 101 to the center of the projected image (i.e., the center of the imaging plane 20) is used as the projection distance for projection. When the projected image is large, the edge area of ​​the projected image is out of focus due to its distance from the center of the projected image, which causes the projected image to be blurred, greatly reducing the user experience.

[0078] In order to solve at least one of the above technical problems, the embodiment of the present disclosure provides a focusing method of a projector and a projector. The focusing method of the projector and the projector provided by the embodiment of the present disclosure will be further described in detail below in combination with the accompanying drawings and specific implementation methods.

[0079] In a first aspect, embodiments of the present disclosure provide a method for focusing a projector, wherein the projector includes an optical lens 101; an imaging plane 20 (specifically, a screen) for displaying a projected image is provided on the light-emitting side of the optical lens 101. FIG3 is a flow diagram of a method for focusing a projector provided by an embodiment of the present disclosure. As shown in FIG3, the method for focusing a projector includes the following steps S301 to S304.

[0080] S301, acquiring multiple groups of focus points according to relative position parameters between the optical lens and the imaging plane.

[0081] In step S301, the imaging plane 20 is generally rectangular in shape, and the optical lens 101 can form a rectangular projection image and project the rectangular projection image onto the imaging plane 20 to cover the entire imaging plane 20 to achieve a display effect with a maximum area. The relative position parameters between the optical lens 101 and the imaging plane 20 can specifically include the distance and angle between the optical lens 101 and the imaging plane 20.

[0082] It is understood that due to the large area of ​​the imaging plane 20, the distance between the optical lens 101 and the imaging plane 20 here is the distance between the optical lens 101 and the focus point M on the imaging plane 20 (which will be marked in the subsequent figures). Multiple groups of focus points M can be obtained based on the relative position parameters between the optical lens 101 and the imaging plane 20; each group contains one or more focus points M. For example, the focus points M can be divided into three groups, one of which is used as the subsequent first target focus point M1, represented by a solid-line frame, and the other groups are stored or used as the subsequent second target focus point M2 (which will be marked in the subsequent figures), represented by a dotted-line frame. In the subsequent description, three groups of focus points M1 will be used as an example. It is understood that the number of groups of focus points M can be other numbers during each projection process. The distance between each focus point M in different groups and the optical lens 101 can be different, and the distance between each focus point M in the same group and the optical lens 101 is equal.

[0083] S302: Identify the main body of the current projection image, and calculate the area ratio of the main body of the current projection image.

[0084] In step S302, for a specific display scene or video shot, the main subject is the primary object being displayed. For example, a ball in a soccer match or a character in an e-sports game is the main subject of the entire projected image. A camera or other image recognition device can be used to identify the main subject in the projected image and calculate the area percentage of the main subject image within the current projected image.

[0085] S303: Select one of the multiple focus points as a first target focus point according to the area ratio of the main body of the picture in the current projection picture.

[0086] In step S303, for example, if the current projection screen is a football match or e-sports match screen, and the main body of the screen occupies a relatively small area in the current projection screen, and the main body of the screen is at the center of the entire projection screen, a focus point M close to the center of the imaging plane 20 can be selected as the first target focus point M1 for focusing to highlight important information such as the position of the football and the game character. For another example, if the current projection screen is a landscape image or other image of a grand scene, and the main body of the screen occupies a relatively large area in the current projection screen, and the entire projection screen needs to be displayed clearly, multiple focus points M at a certain distance from the center of the imaging plane 20 can be selected as the first target focus point M1 for focusing to prevent the edge areas of the projection screen from being out of focus due to being far from the center of the imaging plane 20, resulting in a blurred projection screen.

[0087] S304: Adjust the relative position parameters between the optical lens and the imaging plane according to the first target focus point.

[0088] In step S304 , the projection image can be further adjusted by adjusting the relative position parameters between the optical lens and the imaging plane 20 , so that the projection image can be clearly projected onto the imaging plane 20 .

[0089] In the focusing method of the projector provided by the embodiment of the present disclosure, multiple groups of focus points M can be obtained based on the relative position parameters between the optical lens 101 and the imaging plane 20, and the multiple groups of focus points M can be stored, wherein the distances between each focus point M and the optical lens 101 in the same group are equal, and the distances between each focus point M and the optical lens 101 in different groups are different. Based on the area ratio of the main body of the picture in the current projection picture, a group of focus points M can be selected as the first target focus points M1 and the relative position parameters between the optical lens and the imaging plane 20 can be adjusted to perform focusing, so that the optical lens 101 projects the projection picture clearly onto the imaging plane 20. In this way, it is not necessary to set the focus point M only at the center of the imaging plane 20. A suitable first target focus point M1 can be selected from the multiple groups of focus points M for focusing, so as to prevent the edge area of ​​the projection picture from being out of focus due to being far away from the center of the imaging plane 20, causing problems such as blurred projection picture, thereby improving the user experience.

[0090] Figure 4 is a schematic diagram of the first focusing method provided by an embodiment of the present disclosure. As shown in Figure 4, when the area of ​​the main body of the picture in the projection picture is less than the first preset value, each group contains a focus point M, and a group of focus points M is selected as the first target focus point M1, and the first target focus point coincides with the center of the imaging plane 20.

[0091] In the focusing method shown in FIG4 , the first preset value can be 20% or a smaller value, and each group includes only one focus point M. Multiple groups of focus points M (three groups are shown in the figure) can be distributed at different positions on the imaging plane 20, for example, they can be distributed on the horizontal centerline of the imaging plane 20, where the first target focus point M1 coincides with the center of the imaging plane 20.

[0092] The projection distance is the distance from the optical lens 101 to the center of the projection screen (i.e., the imaging plane 20). The main control unit 102 obtains the distance from the first target focus point M1 to the optical lens 101 through the focus sensor 105. The main control unit 102 stores a focus curve of the projection distance and the focus of the optical lens 101. The corresponding focus position can be obtained by looking up the focus curve or calculating it through a formula, and the motor is driven to complete the focus. The focus algorithm of this focusing method is simple, and the focus algorithm is not affected by the off-axis of the optical machine and the offset projection of the optical lens 101, and can be used in all scenarios. It is especially suitable for scenes with long-focus projectors and important image information in the center, such as football game images and e-sports games.

[0093] Figure 5 is a schematic diagram of the second focusing method provided by an embodiment of the present disclosure. As shown in Figure 5, when the area of ​​the main body of the picture in the projection picture is greater than the second preset value, the optical lens 101 is arranged directly opposite the center of the imaging plane 20 (only the imaging plane 20 is shown in the figure), and each group contains four focus points M. The four focus points M in each group are evenly arranged around the center of the imaging plane 20 and are respectively located on the two diagonals of the imaging plane 20.

[0094] In the focusing method shown in FIG5 , the second preset value can be selected as 50%, or a larger value, and the optical lens 101 is arranged opposite the center of the imaging plane 20, and each group includes four focus points M. Multiple groups of focus points M (three groups are shown in the figure) can be distributed at different positions on the imaging plane 20. Specifically, the four focus points M are evenly arranged around the center of the imaging plane 20 and are respectively located on the two diagonals of the imaging plane 20. One of the multiple focal points M can be selected as the first target focus point M1. For example, the four first target focus points M1 are respectively located at the 1 / 4 and 3 / 4 positions on the two diagonals of the imaging plane. Since the above-mentioned projection method uses four first target focus points M1 for focusing, the focus area in the projection picture accounts for a larger proportion, so as to prevent the edge area of ​​the projection picture from being out of focus due to being far away from the center of the imaging plane 20, causing problems such as blurred projection picture, thereby improving the user experience.

[0095] It should be noted here that this projection method is suitable for projectors with a small projection ratio (the ratio of projection distance to screen width, the smaller the ratio, the larger the screen width at the same projection distance), that is, short-focus projectors. Its usage conditions require that the optical lens 101 is perpendicular to the imaging plane 20, that is, placed in a forward direction.

[0096] Figure 6 is a schematic diagram of the third focusing method provided by an embodiment of the present disclosure. As shown in Figure 6, when the area of ​​the main body of the picture in the projection picture is greater than the second preset value, the optical lens 101 is set to face the center of the imaging plane 20, and each group contains four focus points M. The four focus points M in each group are evenly arranged around the center of the imaging plane 20 and are located on an equifocal distance circle with the center of the imaging plane 20 as the center.

[0097] The focusing method shown in FIG6 is essentially the same as the focusing method shown in FIG5 , with the second preset value being 50% or greater. Four focus points M are set in each group. The difference between the two is that in the focusing method shown in FIG6 , multiple equifocal circles are formed with the center of the imaging plane 20 as the center. The distances between the focus points M on each equifocal circle and the optical lens 101 are equal, i.e., the projection distances are equal. One of the groups can be selected as the first target focus points M1 for focusing. For example, the equifocal circles containing the four first target focus points M1 fall within the imaging plane 20 and are tangent to at least one edge of the imaging plane 20. When the equifocal circles are tangent to at least one edge of the imaging plane 20 (i.e., the projection image), the perimeter of the equifocal points is maximized, and the projected focus pixel reaches its maximum value. This is suitable for viewing landscape images and grand scenes, preventing the edge areas of the projection image from being out of focus due to being far from the center of the imaging plane 20, causing problems such as blurry projection images, thereby improving the user experience.

[0098] It should be noted here that, similar to the projection method shown in Figure 5 above, the projection method shown in Figure 6 is suitable for projectors with a small projection ratio (the ratio of projection distance to screen width, the smaller the ratio, the larger the screen width at the same projection distance), that is, short-focus projectors. Its use conditions require that the optical lens 101 is perpendicular to the imaging plane 20, that is, placed in a forward direction.

[0099] Specifically, as shown in Figures 5 and 6, the four first target focus points M1 correspond to the four vertices of the same rectangle. Since the imaging plane 20 is generally rectangular, the lines connecting the selected first target focus points M1 can also form a rectangle to ensure that the projected image has the same size, shape, and other parameters as the imaging plane 20, so that the projected image covers the entire imaging plane 20, avoiding partial areas of the imaging plane 20 being blocked from projection and affecting the display effect.

[0100] Figure 7a is a schematic diagram of the fourth focusing method provided by an embodiment of the present disclosure. As shown in Figure 7a, the imaging plane 20 has a first center line and a second center line passing through its center and perpendicular to each other; when the area of ​​the main body of the picture in the projection picture is greater than the second preset value, the optical lens 101 is offset along the second center line, and each group includes two focus points M, and the two focus points M in each group are located on the first center line.

[0101] The first center line can be the horizontal center line of the imaging plane 20, and the second center line can be the vertical center line of the imaging plane 20. The two are perpendicular to each other and intersect at the center of the imaging plane 20. The second preset value can be selected as 50%, or a larger value, and each group contains two focus points M. Multiple groups of focus points M (three groups are shown in the figure) can be distributed at different positions on the imaging plane 20. Specifically, the two focus points M are evenly arranged around the center of the imaging plane 20 and are located on the first center line. One of the multiple focus points M can be selected as the first target focus point M1. For example, the two first target focus points M1 are respectively located at the 1 / 4 and 3 / 4 positions of the first center line. Since the above-mentioned projection method uses two first target focus points M1 for focusing, the focus area in the projection picture accounts for a larger proportion, so as to prevent the edge area of ​​the projection picture from being out of focus due to being far away from the center of the imaging plane 20, causing problems such as blurred projection picture, thereby improving the user experience.

[0102] FIG7b is a schematic diagram of the focusing method shown in FIG7a when the optical lens is offset. As shown in FIG7b , the optical lens 101 can be offset along the second centerline, that is, the optical lens 101 can be offset in the vertical direction of the imaging plane 20. When the optical lens 101 is offset upward, the actual projected image moves upward relative to the isofocal circle at the center of the optical lens 101. The two first target focus points M1 on the first centerline (i.e., the horizontal centerline) remain on the isofocal circle, ensuring that the distances from the two first target focus points M1 to the optical lens 101 (i.e., the projection distance) are equal, thus achieving multi-point focusing.

[0103] The above-mentioned focusing method does not require the optical lens 101 to be perpendicular to the imaging plane 20, that is, placed in a forward direction. This can further facilitate focusing and avoid the projector being affected by space limitations and affecting the focusing accuracy.

[0104] Figure 8a is a schematic diagram of the fifth focusing method provided by an embodiment of the present disclosure. As shown in Figure 8a, the imaging plane 20 has a first center line and a second center line passing through its center and perpendicular to each other; when the area of ​​the main body of the picture in the projection picture is greater than the second preset value, the optical lens 101 is offset along the first center line, and each group includes two focus points M, and the two focus points M in each group are evenly arranged around the center of the imaging plane 20 and are located on the second center line.

[0105] The first center line can be the horizontal center line of the imaging plane 20, and the second center line can be the vertical center line of the imaging plane 20. The two are perpendicular to each other and intersect at the center of the imaging plane 20. The second preset value can be selected as 50%, or a larger value, and each group contains two focus points M. Multiple groups of focus points M (three groups are shown in the figure) can be distributed at different positions on the imaging plane 20. Specifically, the two focus points M are evenly arranged around the center of the imaging plane 20 and are located on the second center line. One of the multiple focal points M can be selected as the first target focus point M1. For example, the two first target focus points M1 are located at 1 / 4 and 3 / 4 of the second center line, respectively. Since the above-mentioned projection method uses two first target focus points M1 for focusing, the focus area in the projection picture accounts for a larger proportion, so as to prevent the edge area of ​​the projection picture from being out of focus due to being far away from the center of the imaging plane 20, causing problems such as blurred projection picture, thereby improving the user experience.

[0106] FIG8b is a schematic diagram of the focusing method shown in FIG8a when the optical lens is offset. As shown in FIG8b, the optical lens 101 can be offset along the first centerline, that is, the optical lens 101 can be offset in the horizontal direction of the imaging plane 20. When the optical lens 101 is offset upward, the actual projected image shifts leftward relative to the isofocal circle at the center of the optical lens 101. The two first target focus points M1 on the second centerline (i.e., the vertical centerline) remain on the isofocal circle, ensuring that the distances from the two first target focus points M1 to the optical lens 101 (i.e., the projection distance) are equal, thus achieving multi-point focusing.

[0107] The above-mentioned focusing method does not require the optical lens 101 to be perpendicular to the imaging plane 20, that is, placed in a forward direction. This can further facilitate focusing and avoid the projector being affected by space limitations and affecting the focusing accuracy.

[0108] Figure 9 is a flow chart of another projector focusing method provided by an embodiment of the present disclosure. As shown in Figure 9, step S304 adjusts the relative position parameters between the optical lens and the imaging plane according to the first target focus point, and then includes step S305, using optical correction and digital correction methods to perform trapezoidal correction on the current projected image.

[0109] When the projector is off-axis or biased, the projection screen will be trapezoidal due to the different projection distances in the vertical direction. Keystone correction is required to adjust the projection screen to a normal projection rectangle. Keystone correction can be done by optical correction or digital correction. Digital correction will cause a certain loss of image quality when processing the image. Therefore, if necessary, try to use front projection (vertical) for projection.

[0110] FIG10 is a flow chart of another method for focusing a projector provided by an embodiment of the present disclosure. As shown in FIG10 , in step S304 , the relative position parameters between the optical lens and the imaging plane are adjusted according to the first target focus point, and then steps S306 to S308 are also included.

[0111] S306 , identifying the main body of the next frame of projection image, and calculating the area ratio of the main body of the next frame of projection image.

[0112] S307 : selecting another group of focus points from the multiple groups as a second target focus point according to the area ratio of the main body of the picture in the next frame of projection.

[0113] S308: Adjust the relative position parameters between the optical lens and the imaging plane according to the second target focus point.

[0114] The projection screen is displayed in the form of video, and the area of ​​the main body of the screen in the projection screen of different frames in the video changes from time to time. For example, the content of the main body of the screen in the projection screen of different frames is different, and the area it occupies is also different. It can be focused again according to the second target focus point M2 (which will be marked in subsequent figures) to achieve real-time dynamic adjustment of the position of the focus point M. The specific implementation principle is similar to the above and will not be described in detail here.

[0115] FIG11 is a flow chart of another method for focusing a projector provided by an embodiment of the present disclosure. As shown in FIG11 , in step S304 , the relative position parameters between the optical lens and the imaging plane are adjusted according to the first target focusing point, and then steps S309 to S311 are also included.

[0116] S309 , identifying the main body of the picture in the next frame of projection picture, and determining the position of the main body of the picture in the next frame of projection picture.

[0117] S310 , selecting another group of focus points from the multiple groups as a second target focus point according to the position of the main body of the picture in the next frame of projection picture.

[0118] S311: Adjust the relative position parameters between the optical lens and the imaging plane according to the second target focus point.

[0119] The projection screen is displayed in the form of a video, and the position of the main body of the screen in the projection screen of different frames in the video changes from time to time. For example, the content of the main body of the screen in the projection screen of different frames is the same, and the area it occupies is also the same, but its position has changed. According to the position of the main body of the screen, a second target focus point M2 (which will be marked in subsequent figures) can be selected, and the focus can be performed again according to the second target focus point M2 to achieve real-time dynamic adjustment of the position of the focus point M. The specific implementation principle is similar to the above and will not be described in detail here.

[0120] FIG12 is a schematic diagram of a focusing method provided by an embodiment of the present disclosure. As shown in FIG12 , the focus point M can be adjusted from the position of a first target focus point M1 to the position of a second target focus point M2 according to the playback image, thereby achieving a clearer projection effect on the main part of the image. For example, when playing a football game, the focus point M can be dynamically adjusted according to the position of the ball, ensuring that the image that the audience is most interested in is always in the focus of the projector, providing a clearer local image and thus improving the viewing experience.

[0121] FIG13a is a schematic diagram illustrating the focal length range of a projector. As shown in FIG13a , generally speaking, a projector has a fixed projection distance range, namely, a minimum and maximum focal length for projection. When the projection distance range is exceeded, the image becomes blurred due to the inability to focus. For example, the projection distance of a certain projector model is 1 to 3 meters. Therefore, in actual use, the distance between the projector's optical lens 101 and the imaging plane 20 is required to fall within the projection distance range. For example, in forward projection, point A is the center of the projected image, i.e., the perpendicular focal length between the optical lens 101 and the imaging plane 20. Point A is the shortest focal length position in this arrangement, and point B is at the edge of the projected image, the required longest focal length position.

[0122] FIG13b is a schematic diagram of the focus point distribution of a projector. As shown in FIG13b , during the autofocus process, the focal length varies between point A and point B. Point A is the center of the projected image, and point B is the edge of the projected image. The focus point M on the imaging plane 20 can vary in focal length between points A and B. Based on user settings, the focus can be dynamically adjusted according to different modes (e.g., movie mode, sports mode, picture mode), or based on the real-time image of the content being played.

[0123] In some embodiments, as shown in Figures 3, 9, 10 and 11, step S301, obtaining multiple groups of focus points based on the relative position parameters between the optical lens and the imaging plane, also includes step S301A, obtaining the relative position parameters between the optical lens and the imaging plane based on the positions of the optical lens and the imaging plane.

[0124] When focusing using a distance sensor, when autofocus begins, the distance sensor first obtains the relative position parameters between the optical lens 101 and the imaging plane 20, including the projection distance and projection angle. The distance sensor can be a ToF sensor, a laser ranging sensor, etc. The focus distance is calculated based on the projection distance and projection angle, and the focus structure adjustment parameters are determined based on the focus distance and the corresponding internally stored curve or calculation formula. The main control unit 102 controls the focus adjustment structure 103 to complete autofocus. Because the focal length is determined using the distance sensor in this method, it can achieve non-sensing focus, that is, the focus parameter measurement, calculation, and initialization of focus are completed during the startup process.

[0125] When using a camera for focusing, when automatic focusing starts, the main control unit 102 first outputs a pattern template of a focus-specific image, and the focusing structure 103 initializes the focus distance. During the traversal process, the camera collects the projected image and matches it with the stored template. When the match is successful, the focus is considered clear, the focal length value is saved, and the initialization focus is completed.

[0126] The distance sensor approach uses invisible light, sound or electromagnetic signals and does not require a focus pattern template, so it can achieve non-sensing focus. The camera approach cannot achieve non-sensing focus, but the camera solution is a sampling feedback method with stronger controllable effects. The camera can also add the function of automatic obstacle avoidance. Both have their advantages and disadvantages. In actual applications, high-end solutions generally adopt a combination of the two.

[0127] In a second aspect, an embodiment of the present disclosure provides a projector. FIG14 is a schematic structural diagram of the projector provided by the embodiment of the present disclosure. As shown in FIG14 , the projector includes: an optical lens 101, a framing structure 201, an image recognition structure 202, a main control unit 102 and a focusing structure 103; an imaging plane 20 for displaying a projection image is provided on the light-emitting side of the optical lens 101; the optical lens 101 is configured to project the projection image onto the imaging plane 20; the framing structure 201 is configured to obtain multiple groups of focus points M based on the relative position parameters between the optical lens 101 and the imaging plane 20; the image recognition structure 202 is configured to identify the image subject in the current projection image and calculate the area ratio of the image subject in the current projection image; the main control unit 102 is configured to select one group of the multiple focus points M as the first target focus point M1 based on the area ratio of the image subject in the current projection image; the focusing structure 102 is configured to adjust the relative position parameters between the optical lens 101 and the imaging plane 20 according to the first target focus point M1.

[0128] The image recognition structure 201 is also configured to identify the main body of the picture in the next frame of projection and calculate the area ratio of the main body of the picture in the next frame of projection; the main control unit 102 is also configured to select another group of focus points from the multiple groups as the second target focus point based on the area ratio of the main body of the picture in the next frame of projection; the focusing structure 103 is also configured to adjust the relative position parameters between the optical lens 101 and the imaging plane 20 according to the second target focus point.

[0129] The image recognition structure 201 is further configured to identify the main subject of the image in the next projected frame and determine its position within the next projected frame. The main control unit 102 is further configured to select another group of focus points M from the multiple groups of focus points as a second target focus point M2 based on the position of the main subject of the image in the next projected frame. The focus adjustment structure 103 is further configured to adjust the relative position parameters between the optical lens 101 and the imaging plane 20 based on the second target focus point M2. As shown in FIG14 , the projector further includes a focus sensor 104. The focus sensor 104 is configured to obtain the relative position parameters between the optical lens 101 and the imaging plane 20 based on their positions.

[0130] It is understandable that the projector provided in the embodiment of the present disclosure further includes structures such as a limit sensor 105 , which has similar functions to the limit sensor 105 in the projector shown in FIG1 and will not be described in detail here.

[0131] The projector provided in the embodiment of the present disclosure is used to implement the focusing method of the projector provided in any of the above embodiments. For specific related descriptions, please refer to the description of the focusing method of the projector in any of the above embodiments, which will not be repeated here.

[0132] In a third aspect, an embodiment of the present disclosure provides an electronic device. FIG15 is a schematic structural diagram of an electronic device provided in some embodiments of the present disclosure. As shown in FIG15 , the electronic device includes: one or more processors 1501; a memory 1502, on which one or more programs are stored. When the one or more programs are executed by one or more processors, the one or more processors implement the focusing method of the projector provided in any of the above embodiments; one or more I / O interfaces 1503, connected between the processor and the memory, and configured to implement information interaction between the processor and the memory.

[0133] Among them, the processor 1501 is a device with data processing capabilities, including but not limited to a central processing unit (CPU); the memory 1502 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory (FLASH); the I / O interface (read-write interface) 1503 is connected between the processor 1501 and the memory 1502, and can realize information interaction between the processor 1501 and the memory 1502, including but not limited to a data bus (Bus), etc.

[0134] In some embodiments, the processor 1501 , the memory 1502 , and the I / O interface 1503 are connected to each other via a bus, and further connected to other components of the computing device.

[0135] In a fourth aspect, this embodiment provides a computer-readable medium having a computer program stored thereon, and when the program is executed by a processor, the focusing method of the projector provided by any of the above embodiments is implemented.

[0136] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As is well known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable, and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those skilled in the art that communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0137] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions and operations of the projector focusing method, projector, electronic device and computer-readable storage medium according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the aforementioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two connected boxes can actually represent basically parallel execution, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or can be implemented using a combination of dedicated hardware and computer instructions.

[0138] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A focusing method for a projector, the projector comprising: Optical lens; An imaging plane for displaying a projection image is provided on the light-emitting side of the optical lens; wherein, the focusing method of the projector includes: Obtaining multiple sets of focus points according to the relative position parameters between the optical lens and the imaging plane; Identifying the main body of the current projection image and calculating the area ratio of the main body of the image in the current projection image; Selecting a set of focus points from the multiple sets of focus points as the first target focus point according to the area ratio of the main body of the image in the current projection image; Adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point.

2. The focusing method of the projector according to claim 1, wherein, When the area ratio of the main body of the image in the projection image is less than a first preset value, each set contains one of the focus points, and a set of the focus points is selected as the first target focus point, and the first target focus point coincides with the center of the imaging plane.

3. The focusing method of the projector according to claim 1, wherein, When the area ratio of the main body of the image in the projection image is greater than a second preset value, the optical lens is disposed opposite to the center of the imaging plane, each set contains four focus points, and the four focus points in each set are evenly arranged around the center of the imaging plane and are respectively located on two diagonal lines of the imaging plane.

4. The focusing method of the projector according to claim 3, wherein, Selecting a set of the focus points as the first target focus point, and the four first target focus points are respectively located at the 1 / 4 and 3 / 4 positions on two diagonal lines of the imaging plane.

5. The focusing method of the projector according to claim 1, wherein, When the area ratio of the main body of the image in the projection image is greater than a second preset value, the optical lens is disposed opposite to the center of the imaging plane, each set contains four focus points, and the four focus points in each set are evenly arranged around the center of the imaging plane and are located on an equal focal length circle with the center of the imaging plane as the center of the circle.

6. The focusing method of the projector according to claim 5, wherein, Selecting a set of the focus points as the first target focus point, and the equal focal length circle where the four first target focus points are located falls within the imaging plane and is tangent to at least one edge of the imaging plane.

7. The focusing method of the projector according to claim 1, wherein, The imaging plane has a first median line and a second median line that pass through its center and are perpendicular to each other; when the area ratio of the main body of the image in the projection image is greater than a second preset value, the optical lens is offset along the direction of the second median line, each set contains two focus points, and the two focus points in each set are evenly arranged around the center of the imaging plane and are located on the first median line; or, the optical lens is offset along the direction of the first median line, each set contains two focus points, and the two focus points in each set are evenly arranged around the center of the imaging plane and are located on the second median line.

8. The focusing method of the projector according to claim 7, wherein, Selecting a set of the focus points as the first target focus point, and the two first target focus points are respectively located at the 1 / 4 and 3 / 4 positions of the first median line, or the two first target focus points are respectively located at the 1 / 4 and 3 / 4 positions of the second median line.

9. The focusing method according to claim 8, wherein, After adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point, the method further includes: Performing trapezoidal correction on the current projection image by using an optical correction method and a digital correction method.

10. The focusing method of the projector according to claim 1, wherein, After adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point, the following steps are further included: Identify the main subject in the next frame of the projection screen and calculate the area ratio of the main subject in the next frame of the projection screen; According to the area ratio of the main subject in the next frame of the projection screen, select another group from multiple groups of focus points as the second target focus point; According to the second target focus point, adjust the relative position parameters between the optical lens and the imaging plane. After adjusting the relative position parameters between the optical lens and the imaging plane according to the first target focus point, the following steps are further included:

11. The focusing method of the projector according to claim 1, wherein, Identify the main subject in the next frame of the projection screen and determine the position of the main subject in the next frame of the projection screen; According to the position of the main subject in the next frame of the projection screen, select another group from multiple groups of focus points as the second target focus point; According to the second target focus point, adjust the relative position parameters between the optical lens and the imaging plane. The distance between the first target focus point and the optical lens is within the focal length range of the optical lens; 12. The focusing method of the projector according to claim 10, wherein, The distance between the second target focus point and the optical lens is within the focal length range of the optical lens. Before obtaining multiple groups of focus points according to the relative position parameters between the optical lens and the imaging plane, the following step is further included:

13. The focusing method of the projector according to claim 1, wherein, According to the positions of the optical lens and the imaging plane, obtain the relative position parameters between the optical lens and the imaging plane. The projector includes: an optical lens, a viewfinder structure, an image recognition structure, a main control unit, and a focusing structure; an imaging plane for displaying a projection screen is provided on the light-emitting side of the optical lens; 14. A projector, wherein, The optical lens is configured to project a projection screen onto the imaging plane; The viewfinder structure is configured to obtain multiple groups of focus points according to the relative position parameters between the optical lens and the imaging plane; The image recognition structure is configured to identify the main subject in the current projection screen and calculate the area ratio of the main subject in the current projection screen; The main control unit is configured to select one group from multiple groups of focus points as the first target focus point according to the area ratio of the main subject in the current projection screen; The focusing structure is configured to adjust the relative position parameters between the optical lens and the imaging plane according to the first target focus point.

15. The projector according to claim 14, wherein The image recognition structure is further configured to identify the main subject in the next frame of the projection screen and calculate the area ratio of the main subject in the next frame of the projection screen; The main control unit is further configured to select another group from multiple groups of focus points as the second target focus point according to the area ratio of the main subject in the next frame of the projection screen; The focusing structure is further configured to adjust the relative position parameters between the optical lens and the imaging plane according to the second target focus point.

16. The projection according to claim 14, wherein ​ The image recognition structure is further configured to recognize the main subject in the next frame of the projection screen and determine the position of the main subject in the next frame of the projection screen; The main control unit is further configured to select another group of focus points from the multiple groups of focus points as the second target focus points according to the position of the main subject in the next frame of the projection screen; The focusing structure is further configured to adjust the relative position parameter between the optical lens and the imaging plane according to the second target focus points.

17. The projector according to claim 14, wherein, The projector further includes: a focus sensor; The focus sensor is configured to obtain the relative position parameter between the optical lens and the imaging plane according to the positions of the optical lens and the imaging plane.

18. An electronic device, wherein, The electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores one or more computer programs executable by the at least one processor, and the one or more computer programs are executed by the at least one processor so that the at least one processor can execute the focusing method of the projector according to any one of claims 1-13.

19. A computer-readable storage medium having a computer program stored thereon, wherein, The computer program, when executed by the processor, implements the focusing method of the projector according to any one of claims 1-13.

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