Virtual image distance measuring method and measuring device of imaging system

Abstract

The invention discloses a virtual image distance measuring method and a virtual image distance measuring device of an imaging system. The virtual image distance measuring method comprises the following steps: placing optical equipment at a coupling-out area position of an imaging system; a light source of the imaging system is controlled to emit light, an imaging image presented in an imaging plane after light emitted by the light source passes through the shading cover plate and the lens is obtained, the actual imaging distance value between a first bright spot and a second bright spot in the imaging image is obtained, the first bright spot is a bright spot formed in the imaging plane by the light passing through the first light through hole, and the second bright spot is a bright spot formed in the imaging plane by the light passing through the second light through hole. The second bright spot is a bright spot formed by light passing through the second light through hole in the imaging surface; and determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging surface and the lens and the distance between the first light through hole and the second light through hole. The invention provides a virtual image distance measuring method and a virtual image distance measuring device of an imaging system, which can improve the efficiency and the precision of determining the virtual image distance of the imaging system.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement technology, and in particular to a virtual image distance measurement method and a measurement device for an imaging system. Background Art

[0002] The measurement of virtual image distance in imaging systems such as Virtual Reality Display and Augmented Reality Display remains a key challenge.

[0003] Most existing virtual image distance measurement technologies use a customized camera lens and change the imaging distance at fixed intervals along the optical axis of the lens, take pictures at different distances, and then calculate the clarity data of each image to find the clearest imaging distance position, and then calculate the virtual image distance.

[0004] However, this measurement method is time-consuming and requires dozens of pictures to fit a relatively accurate curve and find the clearest position. The number of pictures taken will affect the measurement accuracy. This method is time-consuming and will affect the measurement efficiency during batch measurement. In addition, during the measurement, the lens will continue to change relative to the imaging surface, and there will be cumulative errors over a long period of time, which will affect the measurement accuracy and results. Summary of the invention

[0005] The present invention provides a method and a device for measuring the virtual image distance of an imaging system, which can improve the efficiency and accuracy of determining the virtual image distance of the imaging system.

[0006] According to one aspect of the present invention, a method for measuring a virtual image distance of an imaging system is provided, the method comprising:

[0007] Placing an optical device at the outcoupling area of ​​the imaging system; wherein the optical device comprises a light shielding cover and a monocular camera; the monocular camera comprises a lens and an imaging surface; the lens is located on one side of the imaging surface, and the light shielding cover is located on a side of the lens away from the imaging surface; the light shielding cover comprises a first light through hole and a second light through hole arranged at intervals, and the distance between the first light through hole and the second light through hole is greater than a preset distance;

[0008] Controlling the light source of the imaging system to emit light, obtaining an imaging image presented on the imaging surface by the light emitted by the light source after passing through the light shielding cover and the lens, and obtaining an actual imaging distance value between a first bright spot and a second bright spot in the imaging image, wherein the first bright spot is a bright spot formed on the imaging surface by light passing through the first light hole, and the second bright spot is a bright spot formed on the imaging surface by light passing through the second light hole;

[0009] The virtual image distance of the imaging system is determined according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole.

[0010] Optionally, before placing the optical device at the outcoupling region of the imaging system, the method further includes:

[0011] Placing a point light source and the optical device on a measuring platform, and adjusting the position of the point light source and the position of the imaging plane so that the distance between the point light source and the lens is a standard virtual image value, and the imaging plane is located at the focal length of the lens;

[0012] Move the point light source to a first set distance value from the lens, and obtain a first distance between a first bright spot and a second bright spot in the imaging plane, wherein the first set distance value is greater than the standard virtual image value;

[0013] Move the point light source to a second set distance value from the lens, and obtain a second distance between the first bright spot and the second bright spot in the imaging plane, wherein the second set distance value is less than the standard virtual image value;

[0014] After acquiring the actual imaging distance value between the first bright spot and the second bright spot in the image, and before determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole, the method includes:

[0015] Determining whether the actual imaging distance value is greater than or equal to the first spacing and less than or equal to the second spacing;

[0016] If yes, it is preliminarily determined that the imaging system is qualified;

[0017] If not, it is preliminarily determined that the imaging system is unqualified.

[0018] Optionally, determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light through hole and the second light through hole includes:

[0019] Determine the conjugate image distance of the virtual image distance according to the distance between the imaging plane and the lens, the distance between the first light hole and the second light hole in the light shielding cover, and the distance between the first bright spot and the second bright spot in the imaging plane;

[0020] The virtual image distance of the imaging system is determined according to the conjugate image distance, the focal length of the lens and the geometrical optics Gaussian formula.

[0021] Optionally, after determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light through hole and the second light through hole, the method further comprises:

[0022] Determining whether the difference between the virtual image distance and the target virtual image distance is within a set range;

[0023] If so, it is finally determined that the imaging system is qualified.

[0024] Optionally, the imaging system includes a virtual reality wearable device or an augmented reality wearable device.

[0025] Optionally, a vertical projection of a line connecting the center of the first light-through hole and the center of the second light-through hole on the imaging plane coincides with a first set symmetry axis of a vertical projection of the lens on the imaging plane.

[0026] Optionally, the distance from the first center to the second set symmetry axis is not equal to the distance from the second center to the second set symmetry axis, wherein the first center is the center of the vertical projection of the first light hole on the imaging plane, the second center is the center of the vertical projection of the second light hole on the imaging plane, and the second set symmetry axis is any symmetry axis in the vertical projection of the lens on the imaging plane.

[0027] Optionally, the light-shielding cover plate further includes a third light-through hole;

[0028] The third light-through hole is located on one side of a line connecting the center of the first light-through hole and the center of the second light-through hole.

[0029] Optionally, the shape of the first light-through hole and the shape of the second light-through hole are both long strips;

[0030] The long side of the first light-through hole is perpendicular to the long side of the second light-through hole.

[0031] According to another aspect of the present invention, a virtual image distance measuring device for an imaging system is provided, the virtual image distance measuring device comprising: a moving module, a control module and an optical device;

[0032] The moving module is used to place the optical device at the outcoupling area of ​​the imaging system; wherein the optical device includes a light shielding cover and a monocular camera; the monocular camera includes a lens and an imaging surface; the lens is located on one side of the imaging surface, and the light shielding cover is located on the side of the lens away from the imaging surface; the light shielding cover includes a first light through hole and a second light through hole arranged at intervals, and the distance between the first light through hole and the second light through hole is greater than a preset distance;

[0033] The control module is used to control the light source of the imaging system to emit light, obtain an imaging image presented on the imaging surface by the light emitted by the light source after passing through the light shielding cover and the lens, and obtain an actual imaging distance value between a first bright spot and a second bright spot in the imaging image, wherein the first bright spot is a bright spot formed on the imaging surface by light passing through the first light hole, and the second bright spot is a bright spot formed on the imaging surface by light passing through the second light hole;

[0034] The control module is also used to determine the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole.

[0035] An embodiment of the present invention provides a method for measuring the virtual image distance of an imaging system, the method comprising: placing an optical device at a decoupling zone of the imaging system, and controlling the light source of the imaging system to emit light, so as to present an imaging image in an imaging plane in the optical device, and obtaining the actual imaging distance value between the first bright spot and the second bright spot in the imaging image. Then, the virtual image distance of the imaging system is determined according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole. The focal length of the lens and the distance between the first light hole and the second light hole are both fixed values ​​and easy to obtain. The actual imaging distance value can be obtained by taking an imaging image, without taking multiple imaging images to obtain the actual imaging distance value, and without moving the position of the optical device multiple times, thereby reducing the calculation error of the virtual image distance. It can be seen that the method for measuring the virtual image distance of the imaging system provided in this embodiment can improve the efficiency and accuracy of determining the virtual image distance of the imaging system.

[0036] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 is a schematic flow chart of a method for measuring a virtual image distance of an imaging system provided in accordance with an embodiment of the present invention;

[0039] Figure 2is a schematic structural diagram of an optical device provided according to an embodiment of the present invention;

[0040] Figure 3 is a structural schematic diagram of a light shielding cover provided according to an embodiment of the present invention;

[0041] Figure 4 is a schematic diagram of a light path of a point light source passing through an optical device according to an embodiment of the present invention;

[0042] Figure 5 is a schematic diagram of a light path of another point light source passing through an optical device according to an embodiment of the present invention;

[0043] Figure 6 is a schematic diagram of a light path of another point light source passing through an optical device according to an embodiment of the present invention;

[0044] Figure 7 is a schematic flow chart of another method for measuring the virtual image distance of an imaging system provided according to an embodiment of the present invention;

[0045] Figure 8 is a schematic diagram of an optical path for measuring a virtual image distance according to an embodiment of the present invention;

[0046] Fig. 9 is another optical path schematic diagram for measuring virtual image distance provided by an embodiment of the present invention; Fig.10 is another optical path schematic diagram for measuring virtual image distance provided by an embodiment of the present invention;

[0047] Fig.11 is a schematic structural diagram of another light shielding cover provided according to an embodiment of the present invention;

[0048] Fig.12 is a schematic structural diagram of another light shielding cover provided according to an embodiment of the present invention;

[0049] Fig.13 is a schematic structural diagram of another light shielding cover provided according to an embodiment of the present invention;

[0050] Fig.14 is a schematic structural diagram of another light shielding cover provided according to an embodiment of the present invention;

[0051] Fig.15 is a structural schematic diagram of a virtual image distance measuring device of an imaging system provided according to an embodiment of the present invention;

[0052] Fig.16 Detailed description of the invention The figure is a schematic structural diagram of a virtual image distance measuring device for an imaging system provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0055] The virtual image distance of an imaging system refers to the distance from the lens to the virtual image. The virtual image distance is an important parameter because it directly affects the size and shape of the virtual world seen by the user. The virtual image distance cannot be measured directly. The virtual image distance measurement method provided in this embodiment can indirectly measure the virtual image distance of the imaging system by using the lens imaging principle.

[0056] Figure 1 is a flow chart of a method for measuring a virtual image distance of an imaging system according to an embodiment of the present invention, with reference to Figure 1 The method for measuring the virtual image distance of the imaging system provided in this embodiment includes the following steps:

[0057] S110, placing an optical device at the outcoupling area of ​​the imaging system.

[0058] in, Figure 2 is a schematic structural diagram of an optical device provided according to an embodiment of the present invention, Figure 3 is a schematic diagram of a light shielding cover provided according to an embodiment of the present invention, with reference to Figure 2 and Figure 3The optical device provided in this embodiment includes: a light shielding cover 110 and a monocular camera 120; the monocular camera 120 includes a lens 121 and an imaging surface 122; the lens 121 is located on one side of the imaging surface 122, and the light shielding cover 110 is located on the side of the lens 121 away from the imaging surface 122. The light shielding cover 110 includes a first light hole 111 and a second light hole 112 arranged at intervals; the distance between the first light hole 111 and the second light hole 112 is greater than a preset distance. The preset distance is the minimum distance for distinguishing the projection of the first light hole 111 and the projection of the second light hole 112 on the imaging surface 122.

[0059] Specifically, the imaging system includes a waveguide and an outcoupling region, wherein the outcoupling region is used to couple the light beam propagated by total reflection in the waveguide out of the waveguide and transmit it to the human eye. Placing the optical device at the outcoupling region of the imaging system allows the light emitted by the imaging system to be incident into the optical device and form an image on the imaging surface.

[0060] The monocular camera 120 also includes other structures besides the lens 121 and the imaging surface 122. The other structures may be an image sensor, a power supply, a housing, an interface, etc. The lens 121 may be a convex lens.

[0061] The shading cover 110 can be attached to one side of the lens 121 so that the distance between the shading cover 110 and the lens 121 is close to 0, and the light passing through the first light hole 111 and the second light hole 112 can almost all pass through the lens 121, thereby improving the imaging effect on the imaging surface 122.

[0062] The areas except the light holes in the light shielding cover 110 are all light shielding. The vertical projection of the first light hole 111 on the imaging surface 122 and the vertical projection of the second light hole 112 on the imaging surface 122 are both located within the vertical projection of the lens 121 on the imaging surface 122, so that the light emitted by the point light source can be transmitted to the lens 121 through the first light hole 111 and the second light hole 112, and then transmitted to the imaging surface 122 through the lens 121, so that a bright spot formed by the light passing through the first light hole 111 and a bright spot formed by the light passing through the second light hole 112 can be presented on the imaging surface 122, and the bright spot formed by the light passing through the first light hole 111 on the imaging surface 122 is called a first bright spot, and the bright spot formed by the light passing through the second light hole 112 on the imaging surface 122 is called a second bright spot.

[0063] The shape of the boundary of the vertical projection of the light shielding cover 110 on the imaging surface 122 may be the same as the shape of the boundary of the vertical projection of the lens 121 on the imaging surface 122. For example, the shape of the boundary may be circular. The vertical projection of the light shielding cover 110 on the imaging surface 122 may cover the vertical projection of the lens 121 on the imaging surface 122.

[0064] The shape of the first light hole 111 and the shape of the second light hole 112 may be the same. For example, the shape of the first light hole 111 may be rectangular, circular, elliptical, crescent, or triangular. The shape of the first light hole 111 and the shape of the second light hole 112 may also be different. For example, the shape of the first light hole 111 may be one of rectangular, circular, elliptical, crescent, and triangular, and the shape of the second light hole 112 may be another of rectangular, circular, elliptical, crescent, and triangular.

[0065] The following will describe in detail the situation where the optical device is incident with a point light source (the optical device in the following situation is not located in the outcoupling region of the imaging system), and the first bright spot and the second bright spot appear on the imaging surface 122:

[0066] Figure 4 is a schematic diagram of a light path of a point light source passing through an optical device according to an embodiment of the present invention, Figure 5 is a schematic diagram of a light path of another point light source passing through an optical device according to an embodiment of the present invention. Figure 6 is a schematic diagram of a light path of another point light source passing through an optical device according to an embodiment of the present invention, with reference to Figure 4-Figure 6 , the point light source is located on the principal optical axis of the lens 121. When the position between the point light source and the optical device is different, the relative position of the first bright spot and the second bright spot on the imaging surface 122 will be different. Figure 4 , Figure 4 The imaging surface 122 in the image presents a bright spot, that is, the first bright spot coincides with the second bright spot. Figure 5 , Figure 5 The distance between the point light source in and the lens 121 is greater than Figure 4 The distance between the point light source in and the lens 121 is Figure 5 The light path diagram in FIG. 1 shows that the two bright spots in the imaging surface 122 are "inverted", that is, the first light hole 111 in the light shielding cover 110 is located above the second light hole 112, and the first bright spot in the imaging surface 122 is located below the second bright spot. Figure 6 , Figure 6 The distance between the midpoint light source and the lens 121 is less than Figure 4 The distance between the point light source in and the lens 121 is Figure 6 The light path diagram in FIG. 1 can determine that the two bright spots in the imaging surface 122 are “upright”, that is, the first light hole 111 in the light-shielding cover 110 is located above the second light hole 112, and the first bright spot in the imaging surface 122 is located above the second bright spot.

[0067] After the distance between the first bright spot and the second bright spot in the imaging plane 122 is determined, the conjugate image distance S of the virtual image distance of the imaging system can be determined when the optical device provided by this embodiment is applied to the imaging system. ′. Conjugate image distance S ′ The calculation formula is:

[0068]

[0069] Wherein, S is the distance between the imaging surface 122 and the lens 121, D is the distance between the first light hole 111 and the second light hole 112 in the light shielding cover 110, and d is the distance between the first bright spot and the second bright spot in the imaging surface 122. Wherein, S and D may be known, and d may be obtained by measurement. It can be seen that the conjugate image distance S may be determined by measuring d. ′ Then, according to the geometric optics Gaussian formula and the conjugate image distance S ′ Determine the virtual image distance of the imaging system.

[0070] It should be noted that the distance between the first light through hole 111 and the second light through hole 112 may be the distance between the center of the first light through hole 111 and the center of the second light through hole 112 .

[0071] S120, controlling the light source of the imaging system to emit light, obtaining an imaging image presented on the imaging surface after the light emitted by the light source passes through the light shielding cover and the lens, and obtaining an actual imaging distance value between the first bright spot and the second bright spot in the imaging image.

[0072] Specifically, under the condition that the first light hole is located above the second light hole, if the first bright spot in the image is located above the second bright spot, the actual imaging distance value takes a positive value; if the first bright spot in the image is located below the second bright spot, the actual imaging distance value takes a negative value.

[0073] S130, determining a virtual image distance of the imaging system according to an actual imaging distance value, a focal length of the lens, a distance between the imaging plane and the lens, and a distance between the first light through hole and the second light through hole.

[0074] Specifically, the virtual image distance of the imaging system can be determined by using the principle of similar triangles, a light path diagram of a light source passing through a light shielding cover and a lens to reach an imaging surface, and a Gaussian formula of geometric optics.

[0075] The present embodiment provides a method for measuring the virtual image distance of an imaging system, the method comprising: placing an optical device at a coupling-out region of the imaging system, and controlling the light source of the imaging system to emit light, so as to present an imaging image in an imaging plane in the optical device, and obtaining the actual imaging distance value between the first bright spot and the second bright spot in the imaging image. Then, the virtual image distance of the imaging system is determined according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole. The focal length of the lens and the distance between the first light hole and the second light hole are both fixed values ​​and easy to obtain. The actual imaging distance value can be obtained by taking an imaging image, without taking multiple imaging images to obtain the actual imaging distance value, and without moving the position of the optical device multiple times, thereby reducing the calculation error of the virtual image distance. It can be seen that the method for measuring the virtual image distance of the imaging system provided in the present embodiment can improve the efficiency and accuracy of determining the virtual image distance of the imaging system.

[0076] Figure 7 FIG. 1 is a flow chart of another method for measuring the virtual image distance of an imaging system according to an embodiment of the present invention, with reference to FIG. Figure 7 The virtual image distance measurement method provided in this embodiment includes the following steps:

[0077] S210, placing a point light source and an optical device on a measuring platform, adjusting the position of the point light source and the position of the imaging plane so that the distance between the point light source and the lens is a standard virtual image value, and the imaging plane is located at the focal length of the lens.

[0078] Specifically, before executing step S210, the standard virtual image value L of the imaging system and the qualified range of the movable light source in the imaging system are first determined, wherein the qualified range is from L_near to L_far, and L_near is less than L_far. L_far can be a first set distance value from the point light source to the lens, and L_near can be a second set distance value from the point light source to the lens. When executing step S210, the position of the lens can be determined first, and then the point light source is placed at the standard virtual image value L from the lens, and then the position of the imaging surface is adjusted so that only one bright spot appears in the imaging surface, that is, the first bright spot coincides with the second bright spot, and then the light shielding cover, the lens and the imaging surface are fixed to the measuring platform by gluing or screwing. Figure 8 is a schematic diagram of an optical path for measuring virtual image distance according to an embodiment of the present invention, with reference to Figure 8 When the point light source is placed at a standard virtual image value L from the lens 121 , only one bright spot appears in the imaging surface 122 .

[0079] S220, moving the point light source to a first set distance value from the lens, and obtaining a first distance between a first bright spot and a second bright spot in the imaging plane, wherein the first set distance value is greater than a standard virtual image value.

[0080] Specifically, the first spacing refers to the distance between the first bright spot and the second bright spot on the imaging plane. Fig. 9 is another optical path schematic diagram for measuring virtual image distance according to an embodiment of the present invention, with reference to Fig. 9 When the point light source is located at a first set distance value from the lens 121, the first light hole in the light-shielding cover is located above the second light hole, and the first bright spot in the imaging surface 122 is located below the second bright spot, and the first distance between the first bright spot and the second bright spot is taken as -d.

[0081] S230, moving the point light source to a second set distance value from the lens, and obtaining a second distance between the first bright spot and the second bright spot in the imaging plane, wherein the second set distance value is smaller than the standard virtual image value.

[0082] Specifically, the second spacing also refers to the distance between the first bright spot and the second bright spot in the imaging plane. Fig.10 is another optical path schematic diagram for measuring virtual image distance according to an embodiment of the present invention, with reference to Fig.10 When the point light source is located at a second set distance value from the lens 121, the first light hole in the light-shielding cover is located above the second light hole, the first bright spot in the imaging surface 122 is located above the second bright spot, and the second distance between the first bright spot and the second bright spot is taken as d.

[0083] S240, placing the optical device at the outcoupling area of ​​the imaging system.

[0084] Specifically, the content of step S240 is the same as that of step S110. For the description of step S240, please refer to the description of step S110, which will not be repeated here.

[0085] S250, controlling the light source of the imaging system to emit light, obtaining an imaging image presented on the imaging surface after the light emitted by the light source passes through the light shielding cover and the lens, and obtaining an actual imaging distance value between the first bright spot and the second bright spot in the imaging image.

[0086] Specifically, the content of step S250 is the same as that of step S120. For the description of step S250, please refer to the description of step S120, which will not be repeated here.

[0087] S260: Determine whether the actual imaging distance value is greater than or equal to the first spacing and less than or equal to the second spacing.

[0088] If yes, execute step S270; if no, execute step S280.

[0089] S270. Preliminarily determine that the imaging system is qualified.

[0090] Specifically, if the actual imaging distance value is greater than or equal to the first spacing and less than or equal to the second spacing, it means that the distance between the light source and the lens in the imaging system is within the qualified range, and thus it can be preliminarily shown that the imaging system is qualified.

[0091] S280. Preliminarily determine that the imaging system is unqualified.

[0092] Specifically, if the actual imaging distance value is not between the first spacing and the second spacing, it means that the distance between the light source and the lens in the imaging system is within an unqualified range, and thus it can be preliminarily indicated that the imaging system is unqualified.

[0093] S290, determining a virtual image distance of the imaging system according to an actual imaging distance value, a focal length of the lens, a distance between the imaging surface and the lens, and a distance between the first light through hole and the second light through hole.

[0094] Specifically, no matter whether the imaging system is initially determined to be qualified, the virtual image distance of the imaging system can be determined, and steps S260 to S280 are a reference parameter for finally judging whether the imaging system is qualified.

[0095] The content of step S290 is the same as that of step S130. For the description of step S290, please refer to the description of step S130, which will not be repeated here.

[0096] It should be noted that in this embodiment, the distance between the first light hole 111 and the second light hole 112 is set to be greater than the preset distance, so that when the light source of the imaging system moves within a qualified range, the distance between the first bright spot and the second bright spot in the imaging plane can be measured.

[0097] Optionally, determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole includes:

[0098] Determine the conjugate image distance of the virtual image distance according to the distance between the imaging plane and the lens, the distance between the first light hole and the second light hole in the light shielding cover, and the distance between the first bright spot and the second bright spot in the imaging plane;

[0099] The virtual image distance of the imaging system is determined based on the conjugate image distance, the focal length of the lens and the Gaussian formula of geometric optics.

[0100] Specifically, the virtual image distance can be determined according to the following formula group:

[0101]

[0102] Where S is the distance between the imaging surface and the lens, D is the distance between the first light hole and the second light hole in the light shielding cover, d is the distance between the first bright spot and the second bright spot in the imaging surface, f is the focal length of the lens, S′ is the conjugate image distance, L ′ the virtual image distance of the imaging system

[0103] Continue to refer to Figure 8-Figure 10 , and the solution process of the virtual image distance will be introduced in detail below:

[0104] According to the Gaussian formula of geometric optics:

[0105]

[0106] According to L and f, the distance S from the imaging plane to the lens can be calculated. The schematic diagram is shown in Figure 8 .

[0107] When at a long distance, that is, when the point light source moves to the first set distance value from the lens 121, let the measured image distance be S ′ , refer to Fig. 9 ,

[0108] At this time, according to S ′ < S, the distance between the first bright spot and the second bright spot in the imaging plane 122 is negative, and the measured value is -d,

[0109]

[0110] Simplified to

[0111]

[0112] When at a short distance, that is, when the point light source moves to the second set distance value from the lens 121, let the measured image distance be S ′ , refer to Fig.10 ,

[0113] At this time, according to S ′ > S, the distance between the first bright spot and the second bright spot in the imaging plane 122 is positive, and the measured value is d,

[0114]

[0115] In summary, the same formula can be used for different distances:

[0116]

[0117] According to the known D and the measured value d, S can be obtained ′ , and the conjugate image distance S of the virtual image distance can be obtained ′ :

[0118]

[0119] Furthermore, according to the Gaussian formula and the known focal length f, the virtual image distance L can be obtained ′ :

[0120]

[0121]

[0122] Optionally, after determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging surface and the lens, and the distance between the first light hole and the second light hole, the method further includes:

[0123] Determine whether the difference between the virtual image distance and the target virtual image distance is within a set range;

[0124] If yes, it is finally determined that the imaging system is qualified.

[0125] Specifically, when the model of the imaging system is determined, the target virtual image distance of the imaging system will be determined. If the difference between the virtual image distance and the target virtual image distance is within the set range, it means that the imaging system is qualified. If the difference between the virtual image distance and the target virtual image distance is not within the set range, it means that the imaging system is unqualified.

[0126] Optionally, the imaging system includes a virtual reality wearable device or an augmented reality wearable device.

[0127] Specifically, the virtual image distance measurement method provided in this embodiment is used to determine the virtual image distance of the virtual reality wearable device and the augmented reality wearable device, which can improve the efficiency and accuracy of determining the virtual image distance of the virtual reality wearable device and the augmented reality wearable device.

[0128] Optionally, a vertical projection of a line connecting the center of the first light-through hole and the center of the second light-through hole on the imaging plane coincides with a first set symmetry axis of a vertical projection of the lens on the imaging plane.

[0129] Specifically, the shape of the vertical projection of the lens on the imaging plane can be circular. The first set symmetry axis is one of the multiple symmetry axes of the vertical projection of the lens on the imaging plane. By setting the vertical projection of the line connecting the center of the first light hole and the center of the second light hole on the imaging plane to coincide with the first set symmetry axis, the spacing between the first light hole and the second light hole can be increased, and the spacing between the first light hole and the second light hole can be approximately equal to the diameter of the vertical projection of the lens on the imaging plane. When the spacing between the first light hole and the second light hole increases, the distance between the first bright spot and the second bright spot in the imaging plane also increases, which can improve the problem of inaccurate d value measurement caused by too small d value, improve the accuracy of d value measurement, and further improve the accuracy of determining the virtual image distance.

[0130] Optional, Fig.11 is a structural schematic diagram of another light shielding cover provided according to an embodiment of the present invention. Fig.12is a structural schematic diagram of another light shielding cover provided according to an embodiment of the present invention, referring to Fig.11 and Fig.12 , the distance between the first center and the second set symmetry axis 123 is not equal to the distance between the second center and the second set symmetry axis 123, wherein the first center is the center of the vertical projection of the first light hole 111 on the imaging plane, the second center is the center of the vertical projection of the second light hole 112 on the imaging plane, and the second set symmetry axis 123 is any symmetry axis in the vertical projection of the lens on the imaging plane.

[0131] Specifically, the distance between the first center and the second set symmetry axis 123 is set to be unequal to the distance between the second center and the second set symmetry axis 123, which indicates that the first center and the second center are not on the second set symmetry axis 123 at the same time. For example, refer to Fig.11 , the first center is not on the second set symmetry axis 123, and the second center is on the second set symmetry axis 123. Fig.12 , the first center is not on the second set symmetry axis 123 , and the second center is not on the second set symmetry axis 123 .

[0132] If the first light hole 111 in the light-shielding cover 110 is located above the second light hole 112, and the first bright spot in the imaging plane is located above the second bright spot, then the distance value between the first bright spot and the second bright spot takes a positive sign; if the first light hole 111 in the light-shielding cover 110 is located above the second light hole 112, and the first bright spot in the imaging plane is located below the second bright spot, then the distance value between the first bright spot and the second bright spot takes a negative sign. When the first bright spot and the second bright spot in the imaging plane are the same size and are located on the same second set symmetry axis 123, it is impossible to distinguish whether the first bright spot is above or below the second bright spot only by the bright spot situation in the imaging plane. In this embodiment, the distance from the first center to the second set symmetry axis 123 is set to be unequal to the distance from the second center to the second set symmetry axis 123, and whether the first bright spot is above or below the second bright spot can be quickly determined by the bright spot situation in the imaging plane. For example, refer to Fig.11 When the first light hole is located on the left side of the second set symmetry axis 123, and the first bright spot is located on the left side of the second set symmetry axis 123 in the imaging plane, the distance value between the first bright spot and the second bright spot is a positive value; when the first light hole is located on the left side of the second set symmetry axis 123, and the first bright spot is located on the right side of the second set symmetry axis 123 in the imaging plane, the distance value between the first bright spot and the second bright spot is a negative value.

[0133] This embodiment can quickly determine the positive or negative value of the distance between the first bright spot and the second bright spot according to the bright spot situation in the imaging surface, and then quickly determine the virtual image distance of the imaging system, further improving the efficiency of determining the virtual image distance.

[0134] Optional, Fig.13 is a structural schematic diagram of another light shielding cover provided according to an embodiment of the present invention, referring to Fig.13 The light shielding cover 110 further includes a third light through hole 113 ; the third light through hole 113 is located on one side of a line connecting the center of the first light through hole 111 and the center of the second light through hole 112 .

[0135] Specifically, the size and shape of the first light hole 111 can correspond to the size and shape of the second light hole 112. The light emitted by the point light source can present a bright spot in the imaging plane through the third light hole 113, and the bright spot is called the third bright spot. The third light hole 113 can be set to play a marking role. For example, in the light shielding cover 110, the third light hole 113 is located on the left side of the line connecting the center of the first light hole 111 and the center of the second light hole 112. If the third bright spot is located on the left side of the line connecting the first bright spot and the second bright spot in the imaging plane, the distance value between the first bright spot and the second bright spot is positive. If the third bright spot is located on the right side of the line connecting the first bright spot and the second bright spot in the imaging plane, the distance value between the first bright spot and the second bright spot is negative. In this embodiment, the third light hole 113 is set, and the positive and negative values ​​of the distance values ​​between the first bright spot and the second bright spot can be quickly determined by the position of the third bright spot in the imaging plane relative to the first bright spot and the second bright spot, so that the virtual image distance of the imaging system can be quickly determined, and the efficiency of determining the virtual image distance can be further improved.

[0136] Optional, Fig.14 is a structural schematic diagram of another light shielding cover provided according to an embodiment of the present invention, referring to Fig.14 The shape of the first light hole 111 and the shape of the second light hole 112 are both long strips; the long side of the first light hole 111 is perpendicular to the long side of the second light hole 112.

[0137] Specifically, the long side refers to the side with the largest size or the axis with the largest size. The long strip shape may be a rectangle, an ellipse, or a racetrack shape, etc. The size of each side of the first light hole 111 may be equal to the size of each side of the second light hole 112. For example, when the shape of the first light hole 111 and the shape of the second light hole 112 are both rectangles, the length of the first light hole 111 may be equal to the length of the second light hole 112, and the width of the first light hole 111 may be equal to the width of the second light hole 112.

[0138] The shapes of the first light hole 111 and the second light hole 112 are both long strips, and an elongated bright spot can be presented on the imaging surface. In this embodiment, the shapes of the first light hole 111 and the second light hole 112 are both long strips, and the long side of the first light hole 111 is perpendicular to the long side of the second light hole 112. The positive and negative values ​​of the distance between the first bright spot and the second bright spot can be directly determined according to the conditions of the first bright spot and the second bright spot on the imaging surface. For example, when the first light hole 111 is located above the second light hole 112, the long side of the first light hole 111 is perpendicular to the first set symmetry axis 124, and the long side of the second light hole 112 is parallel to the first set symmetry axis 124, if the first bright spot on the imaging surface is elongated and the elongated direction is perpendicular to the first set symmetry axis 124, and the first bright spot is located above the second bright spot, then the distance between the first bright spot and the second bright spot takes a positive value. If the first bright spot in the imaging plane is elongated and the elongated direction is perpendicular to the first set symmetry axis 124 , and the first bright spot is located below the second bright spot, the distance between the first bright spot and the second bright spot is a negative value.

[0139] This embodiment sets two light holes, and can quickly determine the positive or negative distance value between the first bright spot and the second bright spot according to the bright spot situation in the imaging surface, and then can quickly determine the virtual image distance of the imaging system, further improving the efficiency of determining the virtual image distance.

[0140] Fig.15 is a schematic structural diagram of a virtual image distance measuring device for an imaging system provided according to an embodiment of the present invention, Fig.16 is a schematic structural diagram of a virtual image distance measuring device for an imaging system provided according to an embodiment of the present invention, with reference to Fig.15 and Fig.16 The virtual image distance measuring device provided in this embodiment includes a moving module ( Fig.15 and Fig.16), a control module 400 and an optical device 100; a moving module is used to place the optical device 100 at the outcoupling area of ​​the imaging system 310, wherein the optical device 100 includes a light shielding cover and a monocular camera; the monocular camera includes a lens and an imaging surface; the lens is located on one side of the imaging surface, and the light shielding cover is located on the side of the lens away from the imaging surface; the light shielding cover includes a first light through hole and a second light through hole arranged at intervals, and the distance between the first light through hole and the second light through hole is greater than a preset distance; the control module 400 is used to control the light source of the imaging system 310 to emit light, obtain an imaging image presented on the imaging surface after the light emitted by the light source passes through the light shielding cover and the lens, and obtain the actual imaging distance value between the first bright spot and the second bright spot in the imaging image, wherein the first bright spot is a bright spot formed on the imaging surface by the light passing through the first light through hole, and the second bright spot is a bright spot formed on the imaging surface by the light passing through the second light through hole; the control module 400 is also used to determine the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging surface and the lens, and the distance between the first light through hole and the second light through hole.

[0141] Specifically, the control module 400 is electrically connected to the optical device 100 and the imaging system 310 , and the control module 400 may be a computer. Fig.15 The imaging system 310 shown is an AR head display. Fig.16 The imaging system 310 shown is a VR headset.

[0142] The virtual image distance measuring device of an imaging system provided in this embodiment has corresponding beneficial effects with the virtual image distance measuring method of an imaging system provided in any embodiment of the present invention. For technical details not elaborated in this embodiment, please refer to the virtual image distance measuring method of an imaging system provided in any embodiment of the present invention.

[0143] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0144] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring the virtual image distance of an imaging system, characterized in that: include: Placing an optical device at the outcoupling area of ​​the imaging system; wherein the optical device comprises a light shielding cover and a monocular camera; the monocular camera comprises a lens and an imaging surface; the lens is located on one side of the imaging surface, and the light shielding cover is located on a side of the lens away from the imaging surface; the light shielding cover comprises a first light through hole and a second light through hole arranged at intervals, and the distance between the first light through hole and the second light through hole is greater than a preset distance; Controlling the light source of the imaging system to emit light, obtaining an imaging image presented on the imaging surface by the light emitted by the light source after passing through the light shielding cover and the lens, and obtaining an actual imaging distance value between a first bright spot and a second bright spot in the imaging image, wherein the first bright spot is a bright spot formed on the imaging surface by light passing through the first light hole, and the second bright spot is a bright spot formed on the imaging surface by light passing through the second light hole; The virtual image distance of the imaging system is determined according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole.

2. The method for measuring virtual image distance according to claim 1, characterized in that: Before placing the optical device at the outcoupling zone of the imaging system, the method further comprises: Placing a point light source and the optical device on a measuring platform, and adjusting the position of the point light source and the position of the imaging plane so that the distance between the point light source and the lens is a standard virtual image value, and the imaging plane is located at the focal length of the lens; Move the point light source to a first set distance value from the lens, and obtain a first distance between a first bright spot and a second bright spot in the imaging plane, wherein the first set distance value is greater than the standard virtual image value; Move the point light source to a second set distance value from the lens, and obtain a second distance between the first bright spot and the second bright spot in the imaging plane, wherein the second set distance value is less than the standard virtual image value; After acquiring the actual imaging distance value between the first bright spot and the second bright spot in the image, and before determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole, the method includes: Determining whether the actual imaging distance value is greater than or equal to the first spacing and less than or equal to the second spacing; If yes, it is preliminarily determined that the imaging system is qualified; If not, it is preliminarily determined that the imaging system is unqualified.

3. The method for measuring virtual image distance according to claim 1, characterized in that: The determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole comprises: Determine the conjugate image distance of the virtual image distance according to the distance between the imaging plane and the lens, the distance between the first light hole and the second light hole in the light shielding cover, and the distance between the first bright spot and the second bright spot in the imaging plane; The virtual image distance of the imaging system is determined according to the conjugate image distance, the focal length of the lens and the geometrical optics Gaussian formula.

4. The method for measuring virtual image distance according to claim 1, characterized in that: After determining the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light through hole and the second light through hole, the method includes: Determining whether the difference between the virtual image distance and the target virtual image distance is within a set range; If so, it is finally determined that the imaging system is qualified.

5. The method for measuring virtual image distance according to claim 1, characterized in that: The imaging system includes a virtual reality wearable device or an augmented reality wearable device.

6. The method for measuring virtual image distance according to claim 1, characterized in that: A vertical projection of a line connecting the center of the first light-through hole and the center of the second light-through hole on the imaging plane coincides with a first set symmetry axis of a vertical projection of the lens on the imaging plane.

7. The method for measuring virtual image distance according to claim 1, characterized in that: The distance between the first center and the second set symmetry axis is not equal to the distance between the second center and the second set symmetry axis, wherein the first center is the center of the vertical projection of the first light hole on the imaging plane, the second center is the center of the vertical projection of the second light hole on the imaging plane, and the second set symmetry axis is any symmetry axis in the vertical projection of the lens on the imaging plane.

8. The method for measuring virtual image distance according to claim 6, characterized in that: The light-shielding cover plate further includes a third light-through hole; The third light-through hole is located on one side of a line connecting the center of the first light-through hole and the center of the second light-through hole.

9. The method for measuring virtual image distance according to claim 6, characterized in that: The shapes of the first light-through hole and the second light-through hole are both long strips; The long side of the first light-through hole is perpendicular to the long side of the second light-through hole.

10. A virtual image distance measuring device for an imaging system, characterized in that: include: Movement modules, control modules and optical devices; The moving module is used to place the optical device at the outcoupling area of ​​the imaging system; wherein the optical device includes a light shielding cover and a monocular camera; the monocular camera includes a lens and an imaging surface; the lens is located on one side of the imaging surface, and the light shielding cover is located on the side of the lens away from the imaging surface; the light shielding cover includes a first light through hole and a second light through hole arranged at intervals, and the distance between the first light through hole and the second light through hole is greater than a preset distance; The control module is used to control the light source of the imaging system to emit light, obtain an imaging image presented on the imaging surface by the light emitted by the light source after passing through the light shielding cover and the lens, and obtain an actual imaging distance value between a first bright spot and a second bright spot in the imaging image, wherein the first bright spot is a bright spot formed on the imaging surface by light passing through the first light hole, and the second bright spot is a bright spot formed on the imaging surface by light passing through the second light hole; The control module is also used to determine the virtual image distance of the imaging system according to the actual imaging distance value, the focal length of the lens, the distance between the imaging plane and the lens, and the distance between the first light hole and the second light hole.

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