Lens focal length extension method, device and camera

Abstract

The present application discloses a lens focal length extension method, device and camera. The first object distance curve of the lens and each first following curve determine a virtual stroke outside the effective stroke of the first zoom group, and each second following curve that links the first zoom group and each second zoom group is determined within the virtual stroke. For each second zoom group, the second zoom group stroke corresponding to the second following curve corresponding to the second zoom group is different from the second zoom group stroke of the adjacent focal length in the corresponding first following curve. Within the virtual stroke, the stroke position of the first zoom group is kept fixed, and the movement of each second zoom group is controlled according to each second following curve, and the focus group in the lens is controlled to be linked to focus on the target object; the second object distance curve is obtained. Then, the lens is focused. Thereby, the extension of the lens focal length is achieved.

Description

Technical Field

[0001] The present application relates to the field of video surveillance technology, and in particular to a lens focal length extension method, device and camera. Background Art

[0002] With the continuous expansion of the security market and the continuous integration of artificial intelligence (AI) technology, higher and higher requirements are placed on the performance of lenses commonly used in front-end cameras, such as wider focal lengths, faster speeds, higher precision, and longer lifespans. In order to improve rigid indicators such as focal length within a limited device volume, a multi-group zoom group movement lens design is adopted, which usually has a focus group and multiple zoom groups.

[0003] In the related art, the focal length range of the lens is generally determined by the effective travel of one zoom group. The effective travel of the focus group and other zoom groups is not considered, which makes it impossible to fully explore the focal length of the lens, resulting in a certain degree of performance waste of the lens structure. Summary of the invention

[0004] The present application provides a lens focal length extension method, device and camera, which are used to solve the problem that the focal length of the lens in the prior art cannot be fully exploited, resulting in performance waste of the lens structure to a certain extent.

[0005] In a first aspect, the present application provides a method for extending the focal length of a lens, the method comprising:

[0006] Acquire a focus control parameter of the lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameter; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective range of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective range of the first zoom group; wherein the first zoom group is a zoom group with the greatest zoom sensitivity in the lens, and other zoom groups serve as each second zoom group;

[0007] Determine a virtual journey outside the effective journey of the first zoom group, and determine each second following curve linked to the first zoom group and each second zoom group within the virtual journey, wherein, for each second zoom group, a second zoom group journey corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group journey of an adjacent focal length in the corresponding first following curve; wherein the adjacent focal length refers to a focal length within the effective journey that is adjacent to the virtual journey;

[0008] In the virtual stroke, the stroke position of the first zoom group is kept fixed, each second zoom group is controlled to move according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; and a second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke is obtained;

[0009] Focusing control is performed on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves.

[0010] In a second aspect, the present application provides a lens focal length extension device, the device comprising:

[0011] A first determination module is used to obtain a focus control parameter of a lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameter; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective stroke of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective stroke of the first zoom group; wherein the first zoom group is a zoom group with the greatest zoom sensitivity in the lens, and other zoom groups serve as each second zoom group;

[0012] a second determination module, configured to determine a virtual itinerary outside the effective itinerary of the first zoom group, and determine each second following curve linked to the first zoom group and each second zoom group within the virtual itinerary, wherein, for each second zoom group, a second zoom group itinerary corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group itinerary of an adjacent focal segment in the corresponding first following curve; wherein the adjacent focal segment refers to a focal segment within the effective itinerary that is adjacent to the virtual itinerary;

[0013] A third determination module is used to keep the stroke position of the first zoom group fixed within the virtual stroke, control the movement of each second zoom group according to each second following curve, and control the focus group in the lens to be linked during the movement of each second zoom group to focus on the target object; and obtain a second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke;

[0014] A focus control module is used to perform focus control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves.

[0015] In a third aspect, the present application provides a camera, the camera comprising: a lens and a controller; the lens comprising a first zoom group, a focus group and at least one second zoom group;

[0016] The controller is used to obtain a focus control parameter of a lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameter; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective stroke of a first zoom group in the lens, and each first following curve is a following curve linked to each second zoom group within an effective stroke of the first zoom group; determine a virtual stroke outside the effective stroke of the first zoom group, and determine each second following curve linked to the first zoom group and each second zoom group within the virtual stroke, wherein for each second zoom group, the second zoom group corresponds to The second zoom group stroke corresponding to the second following curve is different from the second zoom group stroke of the adjacent focal length in the corresponding first following curve; within the virtual stroke, the stroke position of the first zoom group is kept fixed, and the movement of each second zoom group is controlled according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; the second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke is obtained; based on the first object distance curve, the second object distance curve, each first following curve and each second following curve, the lens is focused.

[0017] In a fourth aspect, the present application provides a controller, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus;

[0018] Memory, used to store computer programs;

[0019] The processor is used to implement the method when executing the program stored in the memory.

[0020] In a fifth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program implements the described method when executed by a processor.

[0021] In a sixth aspect, the present application provides a computer program product, wherein the computer program product comprises an executable program, and the executable program is executed by a processor to implement the described method.

[0022] The present application provides a lens focal length extension method, device and camera, the method comprising: obtaining a focus control parameter of a lens, and determining a first object distance curve and each first following curve of the lens according to the focus control parameter; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective stroke of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective stroke of the first zoom group; wherein the first zoom group is a zoom group with the greatest zoom sensitivity in the lens, and other zoom groups serve as each second zoom group; determining a virtual stroke outside the effective stroke of the first zoom group, and determining each second following curve linked with the first zoom group and each second zoom group within the virtual stroke, wherein for the For each second zoom group, a second zoom group stroke corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group stroke of an adjacent focal length in the corresponding first following curve; wherein the adjacent focal length refers to a focal length adjacent to the virtual stroke within the effective stroke; within the virtual stroke, the stroke position of the first zoom group is kept fixed, and the movement of each second zoom group is controlled according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is obtained; and the lens is focused based on the first object distance curve, the second object distance curve, each first following curve and each second following curve.

[0023] The above technical solution has the following advantages or beneficial effects:

[0024] In the present application, the first object distance curve and each first following curve of the lens are first determined according to the focus control parameters of the lens, and then the virtual stroke outside the effective stroke of the first zoom group is determined, and each second following curve of the linkage of the first zoom group and each second zoom group is determined within the virtual stroke. Moreover, for each second zoom group, the second zoom group stroke corresponding to the second following curve corresponding to the second zoom group is different from the second zoom group stroke of the adjacent focal length in the corresponding first following curve. Thus, the effective stroke of each second zoom group is further utilized in the virtual stroke. Then, within the virtual stroke, the stroke position of the first zoom group is kept fixed, and each second zoom group is controlled to move according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; and the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is obtained. Thus, the effective stroke of the focus group is further utilized in the virtual stroke. Finally, the lens is focused based on the first object distance curve, the second object distance curve, each first following curve, and each second following curve. This achieves the expansion of the lens focal length. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the first object distance curve in the related art;

[0027] Figure 2 It is a schematic diagram of the first following curve in the related art;

[0028] Figure 3 A schematic diagram of the first lens focal length extension process provided in this application;

[0029] Figure 4 A schematic diagram of the second lens focal length extension process provided in this application;

[0030] Figure 5 A schematic diagram of the third lens focal length extension process provided in this application;

[0031] Figure 6 A schematic diagram of a second object distance curve provided for this application;

[0032] Figure 7 A second following curve schematic diagram provided for this application;

[0033] Figure 8 A control flow chart for extending the focal length of a multi-zoom group movement lens provided in this application;

[0034] Fig. 9 A detailed flowchart of lens focal length extension provided for this application;

[0035] Fig.10 A schematic diagram of the structure of the lens focal length extension device provided in this application;

[0036] Fig.11 A schematic diagram of the camera structure provided for this application. DETAILED DESCRIPTION

[0037] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0038] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0039] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0040] The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0041] The term "module" refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code that is capable of performing the functions associated with that element.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0043] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

[0044] In order to facilitate the understanding of the lens focus extension scheme of the present application, the relevant background of lens focus is first introduced. In the traditional lens structure, a focus group and a zoom group are generally involved. The zoom motor can be used to control the zoom group to move along the optical axis of the lens to achieve lens zoom. The focus motor can be used to control the focus group to move along the optical axis of the lens to achieve lens focusing. With the continuous expansion of the security market and the continuous integration of AI technology, higher and higher requirements are placed on the performance of lenses commonly used in front-end cameras. Such as wider focal length, faster speed, higher precision, longer life, etc. Among them, in order to improve the focal length and other hard indicators under the limited equipment volume, a design scheme of a multi-group zoom group movement lens will be adopted. The multi-group zoom group movement lens generally includes a zoom group and multiple zoom groups. The lens focal length extension scheme involved in this application is a focal length extension scheme for a multi-group zoom group movement lens. Movement lens: also known as all-in-one movement, integrated movement, etc., is a key component of a high-speed ball, mainly used for zoom imaging, which directly affects the quality of the whole machine. The optical zoom and auto focus effects are achieved by driving the various groups in the lens along the optical axis mainly through stepper motors. Generally, the movement lens has one zoom group and one focus group; the multi-zoom group movement lens mainly refers to the movement lens that includes multiple zoom groups and one focus group inside the movement.

[0045] In the related art, the focal length range of the lens is generally determined by the effective travel of one zoom group. The effective travel of the focus group and other zoom groups is not considered, which makes it impossible to fully explore the focal length of the lens, resulting in a certain degree of performance waste of the lens structure. Figure 1 The object distance curve and Figure 2 The following curve shown can reflect that the effective travel of the focus group and other zoom groups is not fully considered, and the focal length of the lens cannot be fully exploited, which causes a certain degree of performance waste in the lens structure. Due to the optical characteristics of the movement lens, at different focal lengths and different object distances, in order to achieve the preset imaging effect, each group in the movement needs to move to a specific position; this specific position is called the object distance curve in a coordinate system with the zoom group as the horizontal coordinate and the focus group as the vertical coordinate. This specific position is called the following curve in a coordinate system with one zoom group as the horizontal coordinate and another zoom group as the vertical coordinate.

[0046] In the current field of multi-zoom group movement lens control, the object distance curve is generally established with the effective stroke of one zoom group as the horizontal coordinate and the stroke of the focus group as the vertical coordinate; the following curve is established with the effective stroke of one zoom group as the horizontal coordinate and the stroke of the other zoom group as the vertical coordinate. The drive control model includes the object distance curve and the following curve.

[0047] Figure 1 is a schematic diagram of the first object distance curve in the related art, such as Figure 1 As shown, the horizontal axis represents the positions of the optical stroke of one of the zoom groups, and the vertical axis represents the positions of the optical stroke of the focus group. Figure 1 The four curves in are the object distance curves corresponding to four classic object distances. Figure 1 The left end is the long focal length, and the right end is the short focal length. Figure 1 As shown in the figure, at the telephoto end, the focus group still has a certain amount of space available within the range of 0-250 steps, and at the short focal end (wide), the focus group still has sufficient space available within the range of 0-2300 steps. It can be seen that the effective travel of the focus group is not fully utilized, which shows that the focal length of the lens cannot be fully exploited, resulting in a certain degree of performance waste of the lens structure.

[0048] Figure 2 It is a schematic diagram of the first following curve in the related art, such as Figure 2 As shown, the horizontal axis is the positions of the optical travel of one zoom group, and the vertical axis is the positions of the optical travel of another zoom group. If the lens includes more than two zoom groups, generally including a main zoom group and multiple auxiliary zoom groups, there is a following curve between the main zoom group and each auxiliary zoom group. Figure 2 Only one following curve is taken as an example for illustration.

[0049] Figure 2 The left end is the long focal length, and the right end is the short focal length. Figure 2As shown in the figure, at the telephoto end, the zoom group still has a certain amount of space available in the range of 0-1000 steps, and at the short focal end (wide), the zoom group still has sufficient space available in the range of 200-1500 steps. It can be found that the effective travel of the vertical axis zoom group is not fully utilized, which reflects that the focal length of the lens cannot be fully exploited, resulting in a certain degree of performance waste of the lens structure.

[0050] It should be noted that although the zoom group mainly plays an auxiliary role in the change of focal length, the focal length of the lens can be adjusted in steps of 10 or even 100. Based on the above considerations, the present application proposes a focal length extension scheme for a multi-group zoom group movement lens. The lens focal length extension process provided by the present application is described in detail below.

[0051] Figure 3 A schematic diagram of the first lens focal length extension process provided in this application, the process comprising the following steps:

[0052] S101: Acquire focus control parameters of a lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameters; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective range of a first zoom group in the lens, and each first following curve is a following curve linked to each second zoom group within an effective range of the first zoom group; wherein the first zoom group is a zoom group with the greatest zoom sensitivity in the lens, and other zoom groups serve as each second zoom group;

[0053] S102: determining a virtual itinerary outside the effective itinerary of the first zoom group, and determining each second following curve linked to the first zoom group and each second zoom group within the virtual itinerary, wherein, for each second zoom group, a second zoom group itinerary corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group itinerary of an adjacent focal segment in the corresponding first following curve; wherein the adjacent focal segment refers to a focal segment within the effective itinerary that is adjacent to the virtual itinerary;

[0054] S103: within the virtual stroke, keeping the stroke position of the first zoom group fixed, controlling the movement of each second zoom group according to each second following curve, and controlling the focus group in the lens to be linked during the movement of each second zoom group to focus on the target object; obtaining a second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke;

[0055] S104: performing focusing control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves.

[0056] The camera includes: a lens and a controller; the lens includes a first zoom group, at least a second zoom group and a focus group; the controller can be a central processing unit CPU, a microprocessor MCU, etc. The lens focal length extension method provided in the present application is applied to the controller in the camera.

[0057] First, obtain the focus control parameters of the lens. After the lens leaves the factory, the supplier generally provides the initial focus control parameters of the lens, and the initial focus control parameters can be directly used as the focus control parameters of the lens. The focus control parameters include object distance curves and following curves with different groups as horizontal and vertical coordinates. For example, the lens includes two zoom groups and one focus group, and the two zoom groups are the first zoom group and the second zoom group. The focus control parameters include an object distance curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the focus group as the vertical coordinate; including a following curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the second zoom group as the vertical coordinate. In the present application, the first object distance curve and each first following curve within the effective stroke of the first zoom group in the lens are determined according to the focus control parameters. Among them, the first object distance curve within the effective stroke of the first zoom group includes an object distance curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the focus group as the vertical coordinate. The first following curve within the effective stroke of the first zoom group includes a following curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the second zoom group as the vertical coordinate. If there are multiple second zoom groups, there are multiple first following curves, and each second zoom group corresponds to a following curve.

[0058] Optionally, the lens includes multiple zoom groups. In this application, any zoom group can be used as the first zoom group, and the other zoom groups can be used as the second zoom group. Alternatively, for each zoom group, the optical length of the zoom group is determined, and the zoom group with the longest optical length is selected as the first zoom group, and the other zoom groups are used as the second zoom group. The optical length of the zoom group refers to the distance between the first lens on the object side and the first lens on the image side of the zoom group along the optical axis.

[0059] Determine a virtual stroke outside the effective stroke of the first zoom group. Optionally, after determining each first following curve, determine a virtual stroke outside the effective stroke of the first zoom group of the horizontal coordinate of each first following curve. The virtual stroke may be determined outside the short focal end of the effective stroke of the first zoom group, or may be determined outside the long focal end of the effective stroke of the first zoom group, or may be determined outside the long focal end and outside the short focal end of the effective stroke of the first zoom group, respectively. For each first following curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the second zoom group as the vertical coordinate, determine the second following curve corresponding to the first zoom group and the second zoom group in the lens within the virtual stroke. The second following curve refers to a following curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the second zoom group as the vertical coordinate within the virtual stroke. It should be noted that the principle of defining the second following curve is that, for each second following curve, the second zoom group stroke corresponding to the second following curve is different from the second zoom group stroke of the adjacent focal segment of the virtual stroke described in the second following curve, and the change trend of the second following curve is the same as the change trend of the first following curve of the adjacent focal segment of the virtual stroke. For example, for the virtual stroke outside the telephoto end, the second zoom group stroke of the adjacent focal segment of the virtual stroke is 1200 to 1400. Then the second zoom group stroke corresponding to the second following curve is, for example, 800 to 1200. For another example, for the virtual stroke outside the short focal end, the second zoom group stroke of the adjacent focal segment of the virtual stroke is 0 to 200. Then the second zoom group stroke corresponding to the second following curve is, for example, 200 to 1200. The second zoom group stroke of the adjacent focal segment of the virtual stroke refers to the second zoom group stroke of the focal segment adjacent to the virtual stroke within the effective stroke.

[0060] In the virtual stroke, the stroke position of the first zoom group is kept fixed. Optionally, in the virtual stroke, the stroke position within the effective stroke of the first zoom group closest to the virtual stroke is determined, and the stroke position of the first zoom group is kept fixed. According to each second following curve, each second zoom group is controlled to be linked with the first zoom group, and during the movement of the second zoom group, the focus group in the lens is controlled to be linked to focus on the target object. It should be noted that each second zoom group is controlled to move according to the set step length according to the second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object. In this way, the second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke can be obtained. The second object distance curve refers to the object distance curve whose horizontal coordinate is the stroke position of the first zoom group and the vertical coordinate is the stroke position of the focus group. It should be noted that there is a linkage relationship between the first zoom group and each second zoom group. For example, in a set of linkage relationships, the first zoom group moves 1 step and the second zoom group moves 6 steps. If different second following curves are defined, the above linkage relationship may be different. When controlling the movement of each second zoom group within the virtual stroke, the movement of the first zoom group is also logically controlled according to the linkage relationship, because this is a virtual stroke outside the effective stroke of the first zoom group, so in the actual driving process, the stroke position of the first zoom group is kept fixed, and in the process of each second zoom group movement, the focus group in the lens is controlled to be linked to focus on the target object. Then, the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke can be obtained.

[0061] Finally, based on the first object distance curve, the second object distance curve, each of the first following curves and each of the second following curves, the lens is focused. The present application adds a second object distance curve and a second following curve within the virtual stroke, so that the target object can also be clearly focused within the virtual stroke, thereby achieving the purpose of extending the focal length.

[0062] In the present application, the first object distance curve and each first following curve of the lens are first determined according to the focus control parameters of the lens, and then the virtual stroke outside the effective stroke of the first zoom group is determined, and each second following curve of the linkage of the first zoom group and each second zoom group is determined within the virtual stroke. Moreover, for each second zoom group, the second zoom group stroke corresponding to the second following curve corresponding to the second zoom group is different from the second zoom group stroke of the adjacent focal length in the corresponding first following curve. Thus, the effective stroke of each second zoom group is further utilized in the virtual stroke. Then, within the virtual stroke, the stroke position of the first zoom group is kept fixed, and each second zoom group is controlled to move according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; and the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is obtained. Thus, the effective stroke of the focus group is further utilized in the virtual stroke. Finally, the lens is focused based on the first object distance curve, the second object distance curve, each first following curve, and each second following curve. This achieves the expansion of the lens focal length.

[0063] In the present application, in order to obtain the focus control parameters of the lens more accurately, the acquisition of the focus control parameters of the lens includes: obtaining the initial focus control parameters of the lens provided by a supplier; simulating the focusing process of the lens according to the initial focus control parameters, and correcting the initial focus control parameters according to the focusing state during the simulation process to obtain the focus control parameters of the lens.

[0064] When the lens leaves the factory, the supplier will generally provide the initial focus control parameters of the lens. In the actual application of the lens, considering the ambient temperature of the lens, the structural limitations of each lens group, and the optical performance, physical performance, consistency differences and other reasons, the initial focus control parameters may not be the accurate focus control parameters of the lens. Based on the above considerations, this application obtains the initial focus control parameters of the lens provided by the supplier, simulates the focusing process of the lens according to the initial focus control parameters, and corrects the initial focus control parameters according to the focusing state during the simulation process to obtain the focus control parameters of the lens.

[0065] The initial focus control parameters include object distance curves corresponding to each classic object distance, and each object distance curve corresponds to a corresponding relationship between the travel positions of each group. For each object distance curve, during the simulation of the focusing process of the lens according to the corresponding relationship between the object distance curve and the travel positions of each group, if a focusing abnormality or the like occurs, the corresponding relationship between the object distance curve and the travel positions of each group is adjusted to obtain a corrected object distance curve. According to the corrected object distance curves corresponding to each classic object distance, the corrected focus control parameters are obtained, and the corrected focus control parameters are used as the focus control parameters of the lens. Similarly, each following curve in the initial focus control parameters can also be corrected and fine-tuned to obtain a more accurate following curve.

[0066] In this application, after obtaining the initial focus control parameters of the lens provided by the supplier, the focusing process of the lens is simulated according to the initial focus control parameters, and the initial focus control parameters are corrected according to the focusing state during the simulation process to obtain the focus control parameters of the lens. This avoids the problem of inaccurate focus control parameters caused by the ambient temperature of the lens, the mechanism limitations of each lens group, and the optical performance, physical performance, consistency differences, etc.

[0067] In the present application, the sensitivity of each zoom group in the lens to the lens zoom is determined respectively, and the zoom group with the greatest sensitivity is determined as the first zoom group.

[0068] The lens includes multiple zoom groups, and for each zoom group, the sensitivity of the zoom group to the lens zoom can be determined. Optionally, each zoom group is controlled to move the same number of stroke steps, and other groups are linked during the movement of each zoom group. For each zoom group, the sensitivity of the lens zoom corresponding to the zoom group is determined according to the lens zoom value before and after the zoom group moves the same number of stroke steps. Optionally, the larger the lens zoom value, the greater the sensitivity of the lens zoom corresponding to the zoom group. Then select the zoom group with the greatest sensitivity to the lens zoom as the first zoom group, and the other zoom groups are all used as the second zoom group. Then determine the following curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the second zoom group as the vertical coordinate, and the object distance curve with the stroke position of the first zoom group as the horizontal coordinate and the stroke position of the focus group as the vertical coordinate. It should be noted that if there are multiple second zoom groups, the first zoom group, the focus group and the multiple second zoom groups are linked during the zoom and autofocus process. For each second zoom group, a following curve can be determined with the travel position of the first zoom group as the horizontal coordinate and the travel position of the second zoom group as the vertical coordinate.

[0069] In this application, determining a virtual itinerary outside the valid itinerary of the first zoom group includes:

[0070] A virtual stroke corresponding to the short focal end and a virtual stroke corresponding to the long focal end outside the effective stroke of the first zoom group are respectively determined; wherein the virtual stroke corresponding to the short focal end is adjacent to the short focal end of the effective stroke of the first zoom group; and the virtual stroke corresponding to the long focal end is adjacent to the long focal end of the effective stroke of the first zoom group.

[0071] In order to further extend the focal length of the lens, the present application determines virtual strokes at the short focal end and the long focal end of the effective stroke of the first zoom group, respectively. The virtual stroke determined at the short focal end of the effective stroke of the first zoom group is a virtual stroke corresponding to the short focal end outside the effective stroke of the first zoom group, and the virtual stroke determined at the long focal end of the effective stroke of the first zoom group is a virtual stroke corresponding to the long focal end outside the effective stroke of the first zoom group. It should be noted that the virtual stroke corresponding to the short focal end is adjacent to the short focal end of the effective stroke of the first zoom group, that is, outside the effective stroke of the first zoom group and adjacent to the short focal end of the effective stroke, the virtual stroke corresponding to the short focal end is determined outward; outside the effective stroke of the first zoom group and adjacent to the long focal end of the effective stroke, the virtual stroke corresponding to the long focal end is determined outward. The effective stroke of the first zoom group, the virtual stroke corresponding to the short focal end, and the virtual stroke corresponding to the long focal end are continuous strokes.

[0072] After determining the first object distance curve and each first following curve of the lens according to the focus control parameter, and before determining a virtual stroke outside the effective stroke of the first zoom group, the method further includes:

[0073] Determine the use stroke of each second zoom group according to each first following curve, and determine the focus end use stroke of the focus group according to the first object distance curve;

[0074] According to the usage itinerary of each second zoom group and the pre-saved valid itinerary of each second zoom group, it is determined that each second zoom group meets the expansion condition; and according to the usage itinerary of the focus group and the pre-saved valid itinerary of the focus group, it is determined that the focus group meets the expansion condition; and a subsequent process of determining a virtual itinerary outside the valid itinerary of the first zoom group is performed.

[0075] In the present application, after determining the first object distance curve and each first following curve of the lens according to the focus control parameter, the effective stroke of the first zoom group and the use stroke of the second zoom group can be determined according to the first following curve with the stroke of the first zoom group as the horizontal coordinate and the stroke of the second zoom group as the vertical coordinate. Figure 2 Taking the following curve shown in FIG. 1 as an example, the effective stroke of the first zoom group is 0 to 1675, the long focal end use stroke of the second zoom group is 1000, and the short focal end use stroke of the second zoom group is 200. According to the first object distance curve with the stroke of the first zoom group as the horizontal coordinate and the stroke of the focus group as the vertical coordinate, the effective stroke of the first zoom group and the focus end use stroke of the focus group can be determined. Figure 1 Taking the object distance curve shown as an example, the effective travel of the first zoom group is 0 to 1675, the long focal end of the focus group has a usable travel of 250-1100, and the short focal end of the focus group has a usable travel of 2300.

[0076] For example, the effective range of the pre-saved second zoom group is 0 to 1500. Taking the telephoto end as an example, the telephoto end use range of the second zoom group is 1000, which means that at the telephoto end, there is sufficient space to use in the 0-1000 walking range, that is, the second zoom group at the telephoto end meets the expansion conditions. Taking the short focal end as an example, the short focal end use range of the second zoom group is 200, and the effective range of the pre-saved second zoom group is 0 to 1500, which means that at the short focal end, there is sufficient space to use in the 200-1500 walking range, that is, the second zoom group at the short focal end meets the expansion conditions.

[0077] For example, the effective stroke of the pre-saved focus group is 0 to 3500. Taking the telephoto end as an example, the telephoto end use stroke of the focus group is 250, which means that at the telephoto end, there is still a certain amount of space available in the 0-250 walking range, that is, the telephoto end focus group meets the expansion conditions. Taking the short focal end as an example, the short focal end use stroke of the focus group is 2300, which means that at the short focal end, there is still enough space available in the 0-2300 walking range, that is, the short focal end focus group meets the expansion conditions.

[0078] At the short focal end, if each second zoom group meets the extension condition and the focus group meets the extension condition, a virtual stroke corresponding to the short focal end outside the effective stroke of the first zoom group is determined. At the long focal end, if each second zoom group meets the extension condition and the focus group meets the extension condition, a virtual stroke corresponding to the long focal end outside the effective stroke of the first zoom group is determined.

[0079] Optionally, the usage range of the second zoom group and the curve change trend of the first following curve at the focus end are determined according to the first following curve, and whether the second zoom group meets the expansion condition is determined according to the curve change trend and the usage range of the second zoom group. Figure 2 As shown, at the telephoto end, the change trend of the first following curve is a downward trend from right to left. At this time, it is determined whether there is a step travel smaller than the use travel of the telephoto end in the second zoom group travel. If so, it is determined that the extension condition is met. Optionally, if there is a step travel smaller than the use travel of the telephoto end in the second zoom group travel, and the number of steps smaller than the use travel of the telephoto end is greater than the preset step threshold, it is determined that the extension condition is met. The preset step threshold is, for example, 50 steps, 100 steps, etc. At the short focal end, the change trend of the first following curve is an upward trend from left to right. At this time, it is determined whether there is a step travel larger than the use travel of the short focal end in the second zoom group travel. If so, it is determined that the extension condition is met. Optionally, if there is a step travel larger than the use travel of the short focal end in the second zoom group travel, and the number of steps larger than the use travel of the short focal end is greater than the preset step threshold, it is determined that the extension condition is met.

[0080] Optionally, the focus end use stroke of the focus group and the curve change trend of the first object distance curve at the focus end are determined according to the first object distance curve, and whether the focus group meets the expansion condition is determined according to the curve change trend and the focus end use stroke of the focus group. Figure 1 As shown, at the telephoto end, the changing trend of the first object distance curve is a decreasing trend from right to left. At this time, it is determined whether there is a step stroke smaller than the stroke used at the telephoto end in the focus group stroke. If so, it is determined that the extension condition is met. Optionally, if there is a step stroke smaller than the stroke used at the telephoto end in the focus group stroke, and the number of steps smaller than the stroke used at the telephoto end is greater than a preset step threshold, it is determined that the extension condition is met. At the short focus end, the changing trend of the first object distance curve is a decreasing trend from left to right. At this time, it is determined whether there is a step stroke smaller than the stroke used at the short focus end in the focus group stroke. If so, it is determined that the extension condition is met. Optionally, if there is a step stroke smaller than the stroke used at the short focus end in the focus group stroke, and the number of steps smaller than the stroke used at the short focus end is greater than a preset step threshold, it is determined that the extension condition is met.

[0081] Figure 4 The second lens focal length extension process provided in this application includes the following steps:

[0082] S201: Acquire focus control parameters of a lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameters; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective range of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective range of the first zoom group;

[0083] S202: Determine the usage stroke of each second zoom group according to each first following curve, and determine the focusing end usage stroke of the focus group according to the first object distance curve; determine whether each second zoom group meets the extension condition according to the usage stroke of each second zoom group and the pre-saved effective stroke of each second zoom group; determine whether the focus group meets the extension condition according to the usage stroke of the focus group and the pre-saved effective stroke of the focus group; if the above all meet the extension condition, determine the virtual stroke outside the effective stroke of the first zoom group.

[0084] S203: determining each second following curve linked to the first zoom group and each second zoom group within the virtual journey, wherein, for each second zoom group, a second zoom group journey corresponding to the second following curve corresponding to the second zoom group is different from a second zoom group journey of an adjacent focal length in the corresponding first following curve;

[0085] S204: within the virtual stroke, keeping the stroke position of the first zoom group fixed, controlling the movement of each second zoom group according to each second following curve, and controlling the focus group in the lens to be linked during the movement of each second zoom group to focus on the target object; obtaining a second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke;

[0086] S205: Performing focusing control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves.

[0087] In the present application, after controlling the focus group linkage in the lens and before obtaining the second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke, the method further includes:

[0088] In the process of focusing on the target object within the virtual stroke, if it is determined that the linkage of the first zoom group, each of the second zoom groups and each of the group structures in the focus group is normal, and it is determined that the optical performance of the lens is normal, a subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is performed; otherwise, each second following curve linked to the first zoom group and each of the second zoom groups is re-determined within the virtual stroke.

[0089] Whether the linkage of each group structure is normal refers to whether the physical collision of each group structure occurs during the process of focusing on the target object within the virtual stroke. When the lens leaves the factory, the physical distance between each group structure at any stroke position and the physical distance caused by a one-step change in the stroke of each group structure can be pre-saved. In the process of focusing on the target object within the virtual stroke, each group structure is linked, and the stroke position of each group structure at each moment can be determined. Based on the above information, it can be determined whether the physical collision of each group structure occurs at each stroke position of each group structure at each moment. If a physical collision occurs, it means that the linkage of each group structure is abnormal; if no physical collision occurs, it means that the linkage of each group structure is normal.

[0090] In the process of focusing on the target object within the virtual stroke, whether the optical performance of the lens is normal generally refers to whether the optical performance of the lens, such as focal length, optical FNO, distortion, sharpness, resolution, etc., is normal. Optionally, for the optical performance, such as focal length, optical FNO, distortion, sharpness, resolution, etc., the corresponding optical performance index ranges can be saved in advance. In the process of focusing on the target object within the virtual stroke, if the optical performance, such as focal length, optical FNO, distortion, sharpness, resolution, etc., of the lens are all within the corresponding optical performance index ranges, it is determined that the optical performance of the lens is normal, otherwise it is determined that the optical performance of the lens is abnormal.

[0091] In the process of focusing on the target object within the virtual stroke, if the linkage of the first zoom group, each of the second zoom groups and the focus group is normal, and the optical performance of the lens is normal, then the subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is performed, otherwise, each second following curve linked by the first zoom group and each of the second zoom groups is redefined within the virtual stroke. It should be noted that each defined second following curve can be a linear following curve or a nonlinear following curve.

[0092] In the present application, determining that the linkage of the group structures in the first zoom group, each of the second zoom groups, and the focus group is normal includes:

[0093] According to the respective group structures of the first zoom group, each second zoom group and the focus group in the lens, if they are linked according to each second following curve and the focus group in the lens is linked to focus on the target object, no physical collision occurs between the group structures, and it is determined that the linkage of the group structures is normal.

[0094] In the virtual stroke, the stroke position of the first zoom group is kept fixed, and the movement of each second zoom group is controlled according to each second follow curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target. According to the respective group structures of the first zoom group, each second zoom group and the focus group in the lens, it is determined whether the linkage of each group structure is normal in the process of focusing on the target in the virtual stroke. The number of second zoom groups may be one or more. During the movement of the second zoom group and the focus group, the stroke position of each group at each moment can be determined. According to the respective group structures of the first zoom group, each second zoom group and the focus group, it can be determined whether a structural collision occurs between the groups at the stroke position of each group at each moment. If so, it is determined that during the process of focusing on the target in the virtual stroke, the linkage of each group structure is abnormal. If not, it is determined that during the process of focusing on the target in the virtual stroke, the linkage of each group structure is normal.

[0095] In this application, determining whether the optical performance of the lens is normal includes:

[0096] In the process of focusing the target object within the virtual stroke, a modulation transfer function (MTF) curve of the lens is determined, and it is determined according to the MTF curve that the optical performance of the lens is normal.

[0097] In this application, within the virtual travel, the travel position of the first zoom group is kept fixed, and each second zoom group is controlled to move according to each second following curve, and during the movement of the second zoom group, the focus group in the lens is controlled to be linked. Figure 1 and Figure 2For example, within the virtual stroke of the telephoto end, the stroke position of the first zoom group is kept fixed at 0, the second zoom group is controlled to move according to the second follow curve, and during the movement of the second zoom group, the focus group in the lens is controlled to be linked. Within the virtual stroke of the short focal end, the stroke position of the first zoom group is kept fixed at 1675, the second zoom group is controlled to move according to the second follow curve, and during the movement of the second zoom group, the focus group in the lens is controlled to be linked. By controlling the focus group in the lens to be linked, the MTF curve of the lens can be determined during the process of focusing on the target object, and the optical performance of the lens can be judged according to the MTF curve. After determining the MTF curve of the lens, according to the MTF curve, a conventional method can be used to judge whether the optical performance of the lens is normal, and the present application does not repeat the above process. In addition, it should be noted that an example method is performed to judge whether the optical performance of the lens is normal according to the MTF curve. The present application can also judge whether the optical performance of the lens is normal by reading the test card linear strip. It can be understood that the present application includes but is not limited to judging whether the optical performance of the lens is normal according to the MTF curve, reading the test card linear strip, and other methods.

[0098] In the present application, if it is determined according to the MTF curve that the optical performance of the lens is normal, the method further includes:

[0099] Acquire optical performance parameters of the lens within the virtual stroke; wherein the optical performance parameters include at least one of an optical FNO parameter, a resolution parameter, a distortion parameter, a sharpness parameter, and a focal length parameter;

[0100] A pre-saved optical performance index range of the lens is obtained, and if it is determined whether the optical performance parameter is within the optical performance index range, it is determined that the optical performance of the lens is normal.

[0101] In the virtual stroke, if the linkage of each group structure is normal and the focus state of the target object is normal, the optical performance parameters of the lens in the virtual stroke are obtained. The optical performance parameters of the lens include focal length, optical FNO, distortion, sharpness, resolution, etc. The obtained optical performance parameters of the lens in the virtual stroke are compared with the pre-saved lens optical performance index range. If the obtained optical performance parameters are within the respective corresponding pre-saved lens optical performance index range, it is determined that the optical performance of the lens is normal when focusing in the virtual stroke, otherwise it is determined that the optical performance of the lens is abnormal. In other words, when the optical performance of the lens is judged to be normal according to both the MTF curve and the optical performance parameters, it is determined that the optical performance of the lens is normal; when the optical performance of the lens is judged to be abnormal according to the MTF curve, or when the optical performance of the lens is judged to be abnormal according to the optical performance parameters, it is determined that the optical performance of the lens is abnormal.

[0102] If the optical performance of the lens is normal, a subsequent process of obtaining a second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is performed. If the optical performance of the lens is abnormal, a second following curve corresponding to the first zoom group and each second zoom group in the lens is redefined within the virtual stroke.

[0103] The second following curve can be a linear curve or a nonlinear curve. When redefining the second following curve, if it is a linear curve, the slope of the second following curve can be adjusted, and if it is a nonlinear curve, the curvature of the second following curve can be adjusted. However, it is necessary to ensure that the second zoom group stroke corresponding to the second following curve is different from the second zoom group stroke of the adjacent focal length of the virtual stroke, and the change trend of the second following curve is the same as the change trend of the first following curve of the adjacent focal length of the virtual stroke.

[0104] Re-determining each second following curve linked to the first zoom group and each second zoom group within the virtual journey includes:

[0105] If the number of times the second following curve is re-determined does not reach a preset number threshold, each second following curve linked to the first zoom group and each second zoom group is re-determined within the virtual journey.

[0106] The controller may save in advance a preset number threshold for defining the second following curve, and within the preset number threshold, when the optical performance of the lens is abnormal, the second following curve is redefined. If the number threshold is reached and it is still determined that the optical performance of the lens is abnormal, it can be determined that the lens focal length extension has failed, and the second following curve is no longer redefined.

[0107] If the linkage of the group structures is abnormal; or if the focus state of the target object is abnormal; or if the optical performance of the lens is abnormal; determine whether the number of times the second following curve is redefined reaches a preset number threshold, if not, redefine the second following curve corresponding to the first zoom group and the second zoom group in the lens within the virtual stroke, if yes, the process ends, determines that the lens focal length extension fails, and does not redefine the second following curve.

[0108] Figure 5 The third lens focal length extension process schematic diagram provided in this application includes the following steps:

[0109] S301: Acquire focus control parameters of a lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameters; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective range of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective range of the first zoom group;

[0110] S302: Determine the use stroke of each second zoom group according to each first following curve, and determine the focus end use stroke of the focus group according to the first object distance curve; determine whether each second zoom group meets the extension condition according to the use stroke of each second zoom group and the pre-saved effective stroke of each second zoom group; determine whether the focus group meets the extension condition according to the use stroke of the focus group and the pre-saved effective stroke of the focus group; if the above all meet the extension condition, determine the virtual stroke outside the effective stroke of the first zoom group;

[0111] S303: determining each second following curve linked to the first zoom group and each second zoom group within the virtual journey, wherein, for each second zoom group, a second zoom group journey corresponding to the second following curve corresponding to the second zoom group is different from a second zoom group journey of an adjacent focal length in the corresponding first following curve;

[0112] S304: within the virtual stroke, keeping the stroke position of the first zoom group fixed, controlling the movement of each second zoom group according to each second following curve, and controlling the focus group in the lens to be linked during the movement of each second zoom group to focus on the target object;

[0113] S305: In the process of focusing the target object within the virtual stroke, if the linkage of the first zoom group, each of the second zoom groups and each group structure in the focus group is normal, and the optical performance of the lens is normal, obtaining a second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke;

[0114] S306: Performing focusing control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves.

[0115] In this application, the first zoom group is used as the main zoom group, and the other second zoom group is used as the auxiliary zoom group. This application proposes to fully tap the focal length capability of the multi-zoom group by increasing the virtual travel of the main zoom group and expanding the object distance curve of the long focal end or short focal end of the auxiliary zoom group according to the actual characteristics of the multi-group lens on the basis of the original effective travel of the main zoom group. Figure 6 The second object distance curve diagram provided for this application is as follows: Figure 8 As shown, the horizontal axis represents the positions of the optical stroke of the main zoom group, and the vertical axis represents the positions of the optical stroke of the focus group. Figure 6 , shows a first object distance curve within the effective range of the main zoom group, and a second object distance curve corresponding to the long focal end and the short focal end. Figure 7 The second following curve schematic diagram provided for this application is as follows: Figure 7 As shown, the horizontal axis represents the positions of the optical stroke of the main zoom group, and the vertical axis represents the positions of the optical stroke of the auxiliary zoom group. Figure 7 , a first following curve within the effective range of the main zoom group, and a second following curve corresponding to the long focal end and the short focal end are shown.

[0116] Figure 7 The second following curve in is the following curve within the extended virtual travel range. Figure 7 The virtual travel of the main zoom group and the auxiliary zoom group follow the expansion of the curve, and the different object distance curves of the focus group are also adjusted accordingly, that is, Figure 6 The second object distance curve is shown.

[0117] like Figure 6 and Figure 7 As shown, within the virtual itinerary, the itineraries of the auxiliary zoom group and the focus group are further utilized, thus achieving the extension of the lens focal length.

[0118] Figure 8 The control flow chart for extending the focal length of the multi-zoom group movement lens provided for this application includes: the lens supplier provides a drive control table and recommended control parameters; confirms the optical stroke of the main zoom group; sets the optical stroke + virtual stroke of the main zoom group; verifies the structure and optical performance of each group; and optimizes the effective stroke + virtual stroke of the main zoom group.

[0119] 1. The lens supplier provides the drive control table and recommended control parameters:

[0120] In the current field of lens control, each group control mainly uses the effective travel range of the main zoom group as the horizontal coordinate and the travel range of the focus group or auxiliary zoom group as the vertical coordinate, and uses this to establish a drive control model. The lens supplier provides a drive control table and other recommended control parameters, combined with the above drive control model to achieve preliminary control.

[0121] 2. Confirmation of the optical travel of the main zoom group:

[0122] The focus curve (object distance curve) of the movement lens is mainly simulated or measured using the zoom and focus linkage model provided by the supplier based on the optical characteristics. A similar method is also used for the multi-zoom group movement, that is, the supplier provides the linkage zoom group following curve, and on this basis simulates the focus object distance curve or the object distance curve measured by the end user. However, due to the limitations of the structure of each group, and subject to differences in optical performance, physical performance, consistency, etc., it may be necessary to cut or update the optical travel of the main zoom group provided by the supplier.

[0123] 3. Main zoom group optical travel + virtual travel settings:

[0124] On the basis of the original main zoom group optical travel, the focal length capability of the multi-zoom group is fully exploited by adding a virtual travel of the main zoom group and expanding one or more auxiliary zoom group long-focus or short-focus following curves according to the actual characteristics of the multi-group lenses. In the newly added virtual travel, the main zoom group only makes logical position changes and is not actually driven physically; one or more auxiliary zoom groups are actually driven logically and physically according to the newly added following curves in the virtual travel; the focus group is actually driven logically and physically according to the newly added object distance curve according to the changes of the auxiliary zoom group, and can automatically focus clearly. Among them, the object distance curve uses the travel of the main zoom group as the horizontal coordinate and the travel of the focus group as the vertical coordinate; the following curve uses the travel of the main zoom group as the horizontal coordinate and the travel of the auxiliary zoom group as the vertical coordinate.

[0125] 4. Verification of each group structure and optical performance, etc.:

[0126] The movement and control of the movement lens are precise, and the relevant parameters are closely related to the optical performance. After adding a virtual stroke based on the existing main zoom group optical stroke, as the auxiliary zoom and focus group movement ranges change, it is necessary to focus on verifying whether the structure of each associated group can support the relevant movement. For example, the movement ranges of some groups of many typical multi-zoom group complex movement lenses have overlapping ranges, and it is necessary to avoid the problem of structural collision during the movement. In addition, as the travel of some groups is adjusted, the optical performance of the lens may also decline. After adding a virtual stroke, it is necessary to examine whether the relevant optical performance is within the available range.

[0127] 5. Optimized effective itinerary + virtual itinerary of the main zoom group:

[0128] After 3 and 4 iterative verifications, without changing the physical structure of the lens and ensuring optical performance, the optimized main zoom group effective stroke + virtual stroke was actually applied to give full play to the focal length capability of the multi-zoom group movement lens.

[0129] Fig. 9 The detailed flow chart of lens focal length extension provided for this application is as follows: Fig. 9 As shown, the following steps are included:

[0130] S401: Lens evaluation: According to the drive control table and recommended control parameters provided by the lens supplier, the travel of each group, the auxiliary zoom group following curve, the focus group object distance curve, etc. are obtained;

[0131] S402: Analyze the overall optical characteristics of the movement and the corresponding characteristics of each group, and confirm the optical travel of the main zoom group;

[0132] S403: Determine whether the focal length can be extended, if yes, proceed to S404, if no, the process ends;

[0133] S404: establishing a main zoom virtual travel range according to the travel ranges and curve tables of the main zoom group and the auxiliary zoom group;

[0134] S405: In the virtual travel range of the main zoom group, the main zoom group only moves logically; one or more auxiliary zoom groups perform actual logical and physical movements according to the newly added follow curve; on this basis, the focus object distance curve is confirmed;

[0135] S406: Verify the structure and optical performance of each group under the virtual trip of the main zoom group;

[0136] S407: Determine whether the structure, optical performance, etc. of each group meet expectations. If yes, proceed to S408; if not, proceed to S404;

[0137] S408: The optimized main zoom group optical stroke + virtual stroke is imported for actual use.

[0138] According to the overall optical characteristics of the movement and the characteristics of each group, this application defines a "main zoom group virtual stroke" on the basis of the main zoom group optical stroke, and expands one or more auxiliary zoom groups' telephoto or short focal length following curves according to the actual characteristics of the multi-group lens to fully tap the focal length capabilities of the multi-zoom group. In the newly added virtual stroke, the main zoom group only makes logical position changes and does not actually move physically; one or more auxiliary zoom groups make logical and physical actual movements according to the newly added following curves; the focus group makes logical and physical actual movements according to the newly added focus curves according to the changes of the auxiliary zoom group, and can automatically focus clearly. Verify whether the structures of each associated group can support related movements, and avoid the problem of mutual collision of structures during the movement; verify the optical performance and effect of the newly added main zoom group virtual stroke; without changing the physical structure of the lens and ensuring the optical performance, the optimized main zoom group effective stroke + virtual stroke is actually applied to give full play to the focal length capabilities of the multi-zoom group movement lens.

[0139] Fig.10 This is a schematic diagram of the structure of a lens focal length extension device provided in the present application, the device comprising:

[0140] The first determination module 111 is used to obtain the focus control parameters of the lens, and determine the first object distance curve and each first following curve of the lens according to the focus control parameters; wherein the first object distance curve is the object distance curve corresponding to the focus group within the effective range of the first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within the effective range of the first zoom group; wherein the first zoom group is the zoom group with the greatest zoom sensitivity in the lens, and the other zoom groups serve as each second zoom group;

[0141] The second determining module 112 is used to determine a virtual itinerary outside the effective itinerary of the first zoom group, and determine each second following curve linked to the first zoom group and each second zoom group within the virtual itinerary, wherein, for each second zoom group, a second zoom group itinerary corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group itinerary of an adjacent focal segment in the corresponding first following curve; wherein the adjacent focal segment refers to a focal segment within the effective itinerary that is adjacent to the virtual itinerary;

[0142] The third determination module 113 is used to keep the stroke position of the first zoom group fixed within the virtual stroke, control the movement of each second zoom group according to each second following curve, and control the focus group in the lens to be linked during the movement of each second zoom group to focus on the target object; and obtain the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke;

[0143] The focus control module 114 is configured to perform focus control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves.

[0144] The second determination module 112 is specifically used to respectively determine a virtual stroke corresponding to the short focal end and a virtual stroke corresponding to the long focal end outside the effective stroke of the first zoom group; wherein the virtual stroke corresponding to the short focal end is adjacent to the short focal end of the effective stroke of the first zoom group; and the virtual stroke corresponding to the long focal end is adjacent to the long focal end of the effective stroke of the first zoom group.

[0145] The first determination module 111 is further used to determine the usage stroke of each second zoom group according to each first following curve, and determine the focusing end usage stroke of the focus group according to the first object distance curve; determine that each second zoom group meets the extension condition according to the usage stroke of each second zoom group and the pre-saved effective stroke of each second zoom group; and determine that the focus group meets the extension condition according to the usage stroke of the focus group and the pre-saved effective stroke of the focus group; and trigger the second determination module 112.

[0146] The third determination module 113 is also used for, during the process of focusing on the target object within the virtual stroke, if it is determined that the linkage of the first zoom group, each of the second zoom groups and each of the group structures in the focus group is normal, and it is determined that the optical performance of the lens is normal, performing a subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke; otherwise, redetermining each second following curve linked to the first zoom group and each of the second zoom groups within the virtual stroke.

[0147] The third determination module 113 is specifically used to determine that the linkage of each group structure is normal if no physical collision occurs between the group structures during the process of focusing on the target object according to the group structures of the first zoom group, each second zoom group and the focus group in the lens.

[0148] The third determination module 113 is specifically configured to determine a modulation transfer function (MTF) curve of the lens during focusing the target object within the virtual stroke, and determine whether the optical performance of the lens is normal according to the MTF curve.

[0149] The third determination module 113 is also used to obtain the optical performance parameters of the lens within the virtual stroke; wherein the optical performance parameters include at least one of an optical FNO parameter, a resolution parameter, a distortion parameter, a sharpness parameter and a focal length parameter; obtain a pre-saved optical performance index range of the lens, and if it is determined whether the optical performance parameters are within the optical performance index range, determine that the optical performance of the lens is normal.

[0150] The third determination module 113 is further configured to redetermine each second following curve linked to the first zoom group and each second zoom group within the virtual trip if the number of times of re-determination of the second following curve does not reach a preset number threshold.

[0151] Fig.11 The schematic diagram of the camera structure provided for the present application includes: a lens 121 and a controller 122; the lens includes a first zoom group 123, a focus group 124 and at least one second zoom group 125;

[0152] The controller 122 is used to obtain the focus control parameters of the lens, and determine the first object distance curve and each first following curve of the lens according to the focus control parameters; wherein the first object distance curve is the object distance curve corresponding to the focus group within the effective stroke of the first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within the effective stroke of the first zoom group; wherein the first zoom group is the zoom group with the greatest zoom sensitivity in the lens, and the other zoom groups serve as each second zoom group; determine a virtual stroke outside the effective stroke of the first zoom group, and determine each second following curve linked with the first zoom group and each second zoom group within the virtual stroke, wherein for each second zoom group, The second zoom group stroke corresponding to the second following curve corresponding to the second zoom group is different from the second zoom group stroke of the adjacent focal length in the corresponding first following curve; wherein the adjacent focal length refers to the focal length adjacent to the virtual stroke within the effective stroke; within the virtual stroke, the stroke position of the first zoom group is kept fixed, and the movement of each second zoom group is controlled according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; the second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke is obtained; and the lens is focused based on the first object distance curve, the second object distance curve, each first following curve and each second following curve.

[0153] Fig.11 Only one second zoom group is used as an example for illustration. This application does not limit the number of second zoom groups.

[0154] The controller 122 is specifically used to respectively determine a virtual stroke corresponding to the short focal end and a virtual stroke corresponding to the long focal end outside the effective stroke of the first zoom group; wherein the virtual stroke corresponding to the short focal end is adjacent to the short focal end of the effective stroke of the first zoom group; and the virtual stroke corresponding to the long focal end is adjacent to the long focal end of the effective stroke of the first zoom group.

[0155] The controller 122 is also used to determine the usage stroke of each second zoom group according to each first following curve, and determine the focusing end usage stroke of the focus group according to the first object distance curve; determine that each second zoom group meets the expansion condition according to the usage stroke of each second zoom group and the pre-saved effective stroke of each second zoom group; and determine that the focus group meets the expansion condition according to the usage stroke of the focus group and the pre-saved effective stroke of the focus group, thereby triggering the second determination module 112.

[0156] The controller 122 is also used for, during the process of focusing on the target object within the virtual stroke, if it is determined that the linkage of the group structures among the first zoom group, each second zoom group and the focus group is normal, and it is determined that the optical performance of the lens is normal, performing a subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke; otherwise, redetermining each second following curve linked to the first zoom group and each second zoom group within the virtual stroke.

[0157] The controller 122 is specifically used to determine that the linkage of each group structure is normal if no physical collision occurs between the group structures during the process of focusing on the target object according to the group structures of the first zoom group, each second zoom group and the focus group in the lens.

[0158] The controller 122 is specifically configured to determine a modulation transfer function (MTF) curve of the lens during the process of focusing the target object within the virtual stroke, and determine whether the optical performance of the lens is normal according to the MTF curve.

[0159] The controller 122 is further used to obtain the optical performance parameters of the lens within the virtual stroke; wherein the optical performance parameters include at least one of an optical FNO parameter, a resolution parameter, a distortion parameter, a sharpness parameter and a focal length parameter; obtain a pre-saved optical performance index range of the lens, and if it is determined whether the optical performance parameters are within the optical performance index range, determine that the optical performance of the lens is normal.

[0160] The controller 122 is further configured to redetermine each second following curve linked to the first zoom group and each second zoom group within the virtual journey if the number of times the second following curve is re-determined does not reach a preset number threshold.

[0161] The present application also provides a computer storage readable storage medium, wherein the computer readable storage medium stores a computer program executable by a controller, and when the program runs on the controller, the controller implements any of the above method steps when executing.

[0162] The present application also provides a computer program product, which includes an executable program, and the executable program is executed by a processor to implement any of the above method steps.

[0163] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0164] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for extending the focal length of a lens, characterized in that: The method comprises: Acquire a focus control parameter of the lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameter; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective range of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective range of the first zoom group; wherein the first zoom group is a zoom group with the greatest zoom sensitivity in the lens, and other zoom groups serve as each second zoom group; Determine a virtual journey outside the effective journey of the first zoom group, and determine each second following curve linked to the first zoom group and each second zoom group within the virtual journey, wherein, for each second zoom group, a second zoom group journey corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group journey of an adjacent focal length in the corresponding first following curve; wherein the adjacent focal length refers to a focal length within the effective journey that is adjacent to the virtual journey; In the virtual stroke, the stroke position of the first zoom group is kept fixed, each second zoom group is controlled to move according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; and a second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke is obtained; performing focusing control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves; After controlling the focus groups in the lens to be linked, and before obtaining a second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke, the method further includes: In the process of focusing on the target object within the virtual stroke, if it is determined that the linkage of the first zoom group, each of the second zoom groups and each of the group structures in the focus group is normal, and it is determined that the optical performance of the lens is normal, a subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is performed; otherwise, each second following curve linked to the first zoom group and each of the second zoom groups is re-determined within the virtual stroke.

2. The method according to claim 1, characterized in that Determining a virtual itinerary outside of the valid itinerary of the first zoom group includes: A virtual stroke corresponding to the short focal end and a virtual stroke corresponding to the long focal end outside the effective stroke of the first zoom group are respectively determined; wherein the virtual stroke corresponding to the short focal end is adjacent to the short focal end of the effective stroke of the first zoom group; and the virtual stroke corresponding to the long focal end is adjacent to the long focal end of the effective stroke of the first zoom group.

3. The method according to claim 1, characterized in that After determining the first object distance curve and each first following curve of the lens according to the focus control parameter, and before determining a virtual stroke outside the effective stroke of the first zoom group, the method further includes: Determine the use stroke of each second zoom group according to each first following curve, and determine the focus end use stroke of the focus group according to the first object distance curve; According to the usage itinerary of each second zoom group and the pre-saved valid itinerary of each second zoom group, it is determined that each second zoom group meets the expansion condition; and according to the usage itinerary of the focus group and the pre-saved valid itinerary of the focus group, it is determined that the focus group meets the expansion condition; and a subsequent process of determining a virtual itinerary outside the valid itinerary of the first zoom group is performed.

4. The method according to claim 1, characterized in that Determining that the group structures in the first zoom group, each of the second zoom groups, and the focus group are linked normally includes: According to the respective group structures of the first zoom group, each second zoom group and the focus group in the lens, if they are linked according to each second following curve and the focus group in the lens is linked to focus on the target object, no physical collision occurs between the group structures, and it is determined that the linkage of the group structures is normal.

5. The method according to claim 1, characterized in that Determining that the optical performance of the lens is normal includes: In the process of focusing the target object within the virtual stroke, a modulation transfer function (MTF) curve of the lens is determined, and it is determined according to the MTF curve that the optical performance of the lens is normal.

6. The method according to claim 5, characterized in that If it is determined according to the MTF curve that the optical performance of the lens is normal, the method further includes: Obtaining optical performance parameters of the lens within the virtual stroke; wherein the optical performance parameters include at least one of an optical FNO parameter, a resolution parameter, a distortion parameter, a sharpness parameter, and a focal length parameter; A pre-saved optical performance index range of the lens is obtained, and if it is determined whether the optical performance parameter is within the optical performance index range, it is determined that the optical performance of the lens is normal.

7. The method according to claim 1, characterized in that Re-determining each second following curve linked to the first zoom group and each second zoom group within the virtual journey includes: If the number of times the second following curve is re-determined does not reach a preset number threshold, each second following curve linked to the first zoom group and each second zoom group is re-determined within the virtual journey.

8. A lens focal length extension device, characterized in that: The device comprises: A first determination module is used to obtain a focus control parameter of a lens, and determine a first object distance curve and each first following curve of the lens according to the focus control parameter; wherein the first object distance curve is an object distance curve corresponding to a focus group within an effective stroke of a first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within an effective stroke of the first zoom group; wherein the first zoom group is a zoom group with the greatest zoom sensitivity in the lens, and other zoom groups serve as each second zoom group; a second determination module, configured to determine a virtual itinerary outside the effective itinerary of the first zoom group, and determine each second following curve linked to the first zoom group and each second zoom group within the virtual itinerary, wherein, for each second zoom group, a second zoom group itinerary corresponding to a second following curve corresponding to the second zoom group is different from a second zoom group itinerary of an adjacent focal segment in the corresponding first following curve; wherein the adjacent focal segment refers to a focal segment within the effective itinerary that is adjacent to the virtual itinerary; A third determination module is used to keep the stroke position of the first zoom group fixed within the virtual stroke, control the movement of each second zoom group according to each second following curve, and control the focus group in the lens to be linked during the movement of each second zoom group to focus on the target object; and obtain a second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke; a focusing control module, configured to perform focusing control on the lens based on the first object distance curve, the second object distance curve, each of the first following curves, and each of the second following curves; The third determination module is also used for, during the process of focusing on the target object within the virtual stroke, if it is determined that the linkage of the group structures among the first zoom group, each second zoom group and the focus group is normal, and it is determined that the optical performance of the lens is normal, performing a subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke; otherwise, redetermining each second following curve linked with the first zoom group and each second zoom group within the virtual stroke.

9. A camera, characterized in that: The camera comprises: a lens and a controller; the lens comprises a first zoom group, a focus group and at least one second zoom group; The controller is used to obtain the focus control parameters of the lens, and determine the first object distance curve and each first following curve of the lens according to the focus control parameters; wherein the first object distance curve is the object distance curve corresponding to the focus group within the effective stroke of the first zoom group in the lens, and each first following curve is a following curve linked with each second zoom group within the effective stroke of the first zoom group; wherein the first zoom group is the zoom group with the greatest zoom sensitivity in the lens, and the other zoom groups serve as each second zoom group; determine a virtual stroke outside the effective stroke of the first zoom group, and determine each second following curve linked with the first zoom group and each second zoom group within the virtual stroke, wherein for each second zoom group, the The second zoom group stroke corresponding to the second following curve corresponding to the second zoom group is different from the second zoom group stroke of the adjacent focal length in the corresponding first following curve; wherein the adjacent focal length refers to the focal length adjacent to the virtual stroke within the effective stroke; within the virtual stroke, the stroke position of the first zoom group is kept fixed, and the movement of each second zoom group is controlled according to each second following curve, and during the movement of each second zoom group, the focus group in the lens is controlled to be linked to focus on the target object; the second object distance curve corresponding to the first zoom group and the focus group within the virtual stroke is obtained; and the lens is focused based on the first object distance curve, the second object distance curve, each first following curve and each second following curve; After controlling the focus groups in the lens to be linked, before obtaining the second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke, in the process of focusing on the target object in the virtual stroke, if it is determined that the linkage between the first zoom group, each second zoom group and each group structure in the focus group is normal, and it is determined that the optical performance of the lens is normal, the subsequent process of obtaining the second object distance curve corresponding to the first zoom group and the focus group in the virtual stroke is performed; otherwise, each second following curve linked to the first zoom group and each second zoom group is re-determined in the virtual stroke.

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