CN108702459B - Automatic exposure method and device for camera - Google Patents
Automatic exposure method and device for camera Download PDFInfo
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- CN108702459B CN108702459B CN201780004423.2A CN201780004423A CN108702459B CN 108702459 B CN108702459 B CN 108702459B CN 201780004423 A CN201780004423 A CN 201780004423A CN 108702459 B CN108702459 B CN 108702459B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/71—Circuitry for evaluating the brightness variation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/76—Circuitry for compensating brightness variation in the scene by influencing the image signals
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Abstract
An auto-exposure method for a camera (400), comprising: detecting the brightness of the current ambient light (S110); inquiring an exposure parameter (S120) corresponding to the brightness of the current environment light in an exposure table, wherein the exposure parameter comprises a relative aperture value, and the relative aperture value and the diaphragm number of the camera (400) form a preset relation; and adjusting an exposure element in the camera (400) according to the exposure parameters (S130). The invention also provides an automatic exposure device for the camera and the camera (400) with the automatic exposure device.
Description
Copyright declaration
The disclosure of this patent document contains material which is subject to copyright protection. The copyright is owned by the copyright owner. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the patent and trademark office official records and records.
Technical Field
The invention belongs to the field of camera imaging, and particularly relates to an automatic exposure method and an automatic exposure device used in equipment with an imaging function, such as a camera.
Background
With the rapid development of imaging technology, cameras are increasingly used in many fields such as medical imaging, astronomical observation, unmanned aerial vehicle shooting, and daily life. Due to the fact that the distance of a shot object is different, or the brightness of the surrounding environment is different, and the like, under various scenes, the camera is often adjusted by switching the lens of the camera or changing the focal length of the zoom lens, and the like, so as to adapt to different shooting requirements.
Parameters within the camera that can control the imaging brightness include aperture size, exposure time, and sensitivity. When the lens of the camera is switched or the focal length of the zoom lens is changed, the size of the aperture in the parameters is suddenly changed, and if the other two parameters cannot be adjusted in a matching manner, the problems of sudden change or oscillation of the image brightness and the like are caused.
The existing solution is mainly to embed a plurality of exposure tables with different f-number grades in a camera, and select corresponding exposure tables for exposure control according to different f-number ranges. This requires multiple exposure tables, consumes resources, and when there is no corresponding exposure table in a certain f-number range, it is very easy to cause the diaphragm control to be abnormal, thereby causing the screen brightness to be abnormal.
Disclosure of Invention
One aspect of the present invention provides an auto exposure method for a camera, including: detecting the brightness of the current ambient light; inquiring an exposure parameter corresponding to the brightness of the current ambient light in an exposure table, wherein the exposure parameter comprises a relative aperture value which is a function of the diaphragm number; and adjusting an exposure element of the camera according to the exposure parameter.
Another aspect of the present invention provides an automatic exposure apparatus for a camera, including: the storage unit is used for storing an exposure table, the exposure table records exposure parameters corresponding to the brightness of different ambient light, the exposure parameters comprise relative aperture values, and the relative aperture values are functions of the number of diaphragm; a brightness detection unit for detecting brightness of the current ambient light; and the control unit is used for inquiring the exposure parameters corresponding to the brightness of the current ambient light in the exposure table and adjusting the exposure element of the camera to meet the exposure parameters.
Another aspect of the present invention provides a camera including an automatic exposure apparatus, wherein the automatic exposure apparatus includes: the storage unit is used for storing an exposure table, the exposure table records exposure parameters corresponding to the brightness of different ambient lights, the exposure parameters comprise relative aperture values, and the relative aperture values are functions of the aperture values; a brightness detection unit for detecting brightness of the current ambient light; and the control unit is used for inquiring the exposure parameters corresponding to the brightness of the current ambient light in the exposure table and adjusting the exposure element of the camera to meet the exposure parameters.
Other aspects of the invention may also include a non-transitory computer readable medium comprising program instructions for: establishing an exposure table, wherein the exposure table records exposure parameters corresponding to the brightness of different environment lights, the exposure parameters comprise relative aperture values, and the relative aperture values are functions of the diaphragm number; detecting the brightness of the current ambient light; and inquiring the exposure parameter corresponding to the brightness of the current ambient light in the exposure table, and adjusting the exposure element of the camera to meet the exposure parameter.
The method, the device and the computer readable medium of the invention can achieve the aim of normal use without modifying the exposure table when the actual range of the aperture changes but the relative range does not change, and can also rapidly create a new exposure table when the relative range of the aperture changes, thereby achieving the aim of rapidly controlling the exposure.
Drawings
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
fig. 1 schematically shows a flowchart of an auto-exposure method for a camera according to an embodiment of the present invention.
Fig. 2 schematically shows a flow chart of a method for automatic exposure of a camera according to another embodiment of the invention.
Fig. 3 schematically shows a block diagram of an automatic exposure apparatus for a camera according to an embodiment of the present invention.
Fig. 4 schematically shows a block diagram of a camera according to an embodiment of the invention.
Detailed Description
Other aspects, advantages and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
In the present invention, the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or.
In this specification, the various embodiments described below which are meant to illustrate the principles of this invention are illustrative only and should not be construed in any way to limit the scope of the invention. The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. The following description includes various specific details to aid understanding, but such details are to be regarded as illustrative only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Moreover, descriptions of well-known functions and constructions are omitted for clarity and conciseness. Further, the same reference numbers are used throughout the drawings for the same or similar functions and operations.
For the method and device of automatic exposure of the camera, the invention mainly considers the scene that how to use less exposure tables to realize exposure control when the lens of the camera is switched or the focal length of the zoom lens is changed and the diaphragm number range is changed, and how to avoid the problem that the diaphragm control is abnormal because a certain diaphragm number range does not have the corresponding exposure table.
In describing embodiments of the present invention in detail below, although a camera is used as an example for illustration, the method and apparatus of the present invention is not limited to use in a camera, and any device using an optical imaging function may make reasonable use of the present invention, such as a video camera, and the like.
An embodiment of the present invention provides an automatic exposure method for a camera, including: detecting the brightness of the current ambient light; inquiring an exposure parameter corresponding to the brightness of the current ambient light in an exposure table, wherein the exposure parameter comprises a relative aperture value which is a function of the diaphragm number; and adjusting an exposure element of the camera according to the exposure parameter.
It is preferable that the second derivative of the function is smaller than 0, so that when the diaphragm amount increases, the increasing trend of the relative diaphragm value becomes gentle, so that the relative diaphragm value can be linearly matched with the actual optical performance of the lens after the diaphragm amount is subjected to a nonlinear mapping.
More preferably, the relative aperture value is linear with the logarithm of the f-number.
The "camera" referred to in the present invention may be any camera having an optical imaging function, and may be, for example, a film camera, a digital camera, or the like. The "camera" of the present invention may also be used in conjunction with a variety of devices, such as a cell phone with a camera function, an unmanned aerial vehicle with a camera function, and the like.
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
Fig. 1 schematically shows a flowchart of an auto-exposure method for a camera according to an embodiment of the present invention.
As shown in fig. 1, the method includes operations S110 to S130.
In operation S110, the brightness of the current ambient light is detected. According to the embodiment of the present invention, detecting the brightness of the current ambient light may be detected using a sensor, such as a light sensor, an optical fiber sensor, or the like. The sensor may be located inside the camera, in the lens of the camera, or outside the camera, and the position of the sensor is not limited in the present invention.
The brightness of the ambient light in the embodiment of the present invention may be a preset brightness level, for example, from 1 to 10 indicates that the brightness of the ambient light is increasingly brighter, and then the level to which the detected brightness of the ambient light belongs, for example, the current brightness of the ambient light belongs to level 3, is determined. It should be understood by those skilled in the art that the brightness of the ambient light in the present invention is not limited to the preset level, and may be a linear correspondence or the like.
In operation S120, an exposure parameter corresponding to the brightness of the current ambient light is looked up in an exposure table. The exposure table records exposure parameters corresponding to different ambient light intensities, and the exposure parameters include relative aperture values, which are functions of the diaphragm number, and preferably, the second derivative of the functions is less than 0. In one embodiment, the relative aperture value is linear with the logarithm of the f-number, but the present invention is not limited thereto, and any function that can moderate the linear change of the f-number is applicable to the present invention.
An aperture is a device for controlling the amount of light that passes through the lens into a light-sensing surface in the body, and is typically located in the lens. The F-number is used to indicate the amount of light passing through the lens, usually expressed as an F-number, and when the F-number is expressed as F-number, for example, written as: f1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, F22, F32, F44, F64, the smaller the F-number, the more the light intake amount in the same unit time, and the light intake amount in the previous gear is twice as large as that in the next gear, for example, the F-number is adjusted from F8 to F5.6, which means that the F-number is adjusted to be higher by one gear, and the light intake amount is doubled. The F-number range is related to the lens of the camera, and represents the adjustable F-number range of the lens, and the F-number ranges of different lenses are different, for example, the F-number range of the lens a is F2.8-F16, the F-number range of the lens B is F4-F32, and so on.
According to the embodiment of the invention, the relative aperture value is in a linear relation with the logarithm of the base 2 of the aperture number. For example:
where LI denotes a relative diaphragm value, Fnum denotes a diaphragm number, Fmax denotes a diaphragm number of a maximum diaphragm of the lens, and LDR denotes a fraction of a first-order diaphragm number range of the lens of the camera, which is equally divided.
For example, if one lens has F2.8 to F16, which are equally divided into 256 × 5 parts, LDR can mean that the first-order F is equally divided into 256 parts. It will be understood by those skilled in the art that LDR represents only the number of parts that equally divide a first gear of the f-number range, and embodiments of the present invention are not limited to the value of LDR, for example LDR may also take 128, meaning that the first gear f-number is equally divided into 128 parts.
According to the embodiment of the invention, the exposure table comprises exposure parameters, and the exposure parameters comprise aperture parameters, exposure time and sensitivity. Under different ambient light brightness, different parameter combinations are adopted to meet the appropriate picture brightness. Wherein the aperture parameter is expressed as a relative aperture value.
By using the relative aperture value instead of the diaphragm amount in the exposure table, the number of exposure tables can be reduced. For example, there is a lens A, the F-number range of the lens A is F2.8-F16 (including 6 adjustable gears: F2.8, F4, F5.6, F8, F11 and F16), the exposure time is 8 s-1/8000 s, and the sensitivity range is 12800-100. Table 1 schematically shows the exposure table corresponding to the lens a, and as shown in table 1, the brightness of the ambient light is increasingly brighter from 1 to 10, and the corresponding exposure parameters are different at different brightness levels.
TABLE 1
For example, there is a lens B, the F-number range of the lens B is F4-F22 (including 6 adjustable gears F4, F5.6, F8, F11, F16 and F22), the exposure time is 8 s-1/8000 s, and the sensitivity range is 12800-100. Table 2 schematically shows the exposure table corresponding to the lens B, as shown in table 2, the brightness of the ambient light is increasingly brighter from 1 to 10, and the corresponding exposure parameters are different at different brightness levels.
TABLE 2
| Brightness of ambient light | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Number of diaphragm | 4.0 | 4.0 | 5.6 | 5.6 | 8.0 | 8.0 | 11.0 | 11.0 | 16 | 22 |
| Relative aperture value | 1 | 1 | 257 | 257 | 513 | 513 | 769 | 769 | 1025 | 1281 |
| Exposure time(s) | 8 | 1/15 | 1/15 | 1/15 | 1/15 | 1/500 | 1/500 | 1/8000 | 1/8000 | 1/8000 |
| Sensitivity of light | 12800 | 12800 | 12800 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
As shown in tables 1 and 2, the ranges of f-numbers of the lens a and the lens B are different, but the ranges of relative aperture values are the same, and two corresponding exposure tables are required if the exposure tables are created using the f-numbers as the exposure parameters, but can be satisfied using only one exposure table if the exposure tables are created using the relative aperture values as the exposure parameters. For example, as the exposure table shown in table 3, which includes the relative diaphragm value, the exposure time, and the sensitivity, lenses having a diaphragm range of 6 adjustable stages, such as a lens having a diaphragm range of F1 to F5.6, a lens having a diaphragm range of F1.4 to F8, a lens having a diaphragm range of F2 to F11, a lens having a diaphragm range of F2.8 to F16, a lens having a diaphragm range of F4 to F22, a lens having a diaphragm range of F5.6 to F32, a lens having a diaphragm range of F8 to F44, and a lens having a diaphragm range of F11 to F64, can be used.
In the embodiment of the invention, the number of exposure tables can be reduced and the storage space can be saved by using the relative aperture value instead of the diaphragm number as the exposure parameter.
TABLE 3
| Brightness of ambient light | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Relative aperture value | 1 | 1 | 257 | 257 | 513 | 513 | 769 | 769 | 1025 | 1281 |
| Exposure time(s) | 8 | 1/15 | 1/15 | 1/15 | 1/15 | 1/500 | 1/500 | 1/8000 | 1/8000 | 1/8000 |
| Sensitivity of light | 12800 | 12800 | 12800 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
It will be understood by those skilled in the art that the exposure table of the present invention is not limited to the form of the table in the above example, but may be a linear comparison table or the like, which may be used to indicate different exposure parameter selections under different ambient light intensities.
Those skilled in the art will understand that the diaphragm number range of the present invention is not limited to the 6 adjustable gear ranges in the above examples, and may also include more or less adjustable gear ranges, such as F1.0-F22 (including 10 adjustable gears: F1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, and F22) or F4-F11 (including 4 adjustable gears: F4, F5.6, F8, and F11), etc., and the diaphragm number range differs according to the lens, and the embodiments of the present invention may establish different exposure tables according to different adjustable gear ranges.
It will be understood by those skilled in the art that the diaphragm amount change of the present invention is not limited to only 1 shift position at a time in the above example, and may be changed by two or three or more shifts, for example, only five shift positions of F1.0, F2.0, F4.0, F8.0, and F22 are used in the diaphragm amount range of F1.0 to F22.
It will be understood by those skilled in the art that the exposure table of the present invention may include only the relative aperture value, exposure time, and sensitivity without the above-mentioned example, and the relative aperture value, exposure time, and sensitivity in the above-mentioned exposure table are not limited to the above-mentioned values, and the above-mentioned example is merely for the purpose of facilitating understanding.
In operation S130, an exposure element of the camera is adjusted according to the exposure parameter. According to the invention, as mentioned above, the exposure parameters comprise relative aperture values, whereby adjusting the exposure elements of the camera in accordance with the exposure parameters comprises: and converting the relative aperture value into an f-number, and adjusting an exposure element of the camera according to the f-number.
For example, the current lens is lens A, the F-number range of lens A is F2.8-F16 (including 6 adjustable gears: F2.8, F4, F5.6, F8, F11 and F16), the exposure time is 8 s-1/8000 s, and the sensitivity range is 12800-100. the exposure table shown in Table 1 can be selected. When it is detected that the brightness of the current ambient light is level 3, the corresponding exposure parameters queried in table 1 are the relative aperture value 257, the exposure time 1/15s, and the sensitivity 12800, the aperture of the camera may be controlled to adjust to the diaphragm size corresponding to the relative aperture value 257 (the aperture is adjusted to F4.0), the shutter exposure time of the camera may be controlled to 1/15s, and the sensitivity 12800 of the camera may be controlled according to the exposure parameters, thereby implementing the automatic exposure of the camera.
According to the embodiment of the invention, the number of the exposure tables can be reduced and the memory space can be reduced by establishing the exposure tables by using the relative aperture value as the exposure parameter.
Fig. 2 schematically shows a flowchart of a method of updating an exposure table for a camera according to another embodiment of the present invention.
As shown in fig. 2, the method includes operations S210 to S240.
In operation S210, lens information is acquired. The acquired lens information includes information such as a lens focal length and a lens aperture range. Acquiring the lens information may be triggering acquisition according to a specific condition, for example, acquiring current lens information when changing a lens or adjusting a focal length of the lens.
In operation S220, it is determined whether the f-number range is changed, and if so, operation S230 is performed, otherwise, the process is ended. According to the embodiment of the invention, if the diaphragm number range is changed, whether the exposure table needs to be updated and adjusted to adapt to new lens information is judged, and if the diaphragm number range is not changed, the current exposure table is used to meet the control of the camera exposure. For example, the diaphragm range can be changed from F2-F16 to F2-F22, or from F2-F16 to F4-F22.
In operation S230, it is determined whether a range of relative aperture values of a lens of the camera changes, and if so, operation S240 is performed, otherwise, the process ends. According to the embodiment of the present invention, the exposure table needs to be updated if the range of the relative aperture value changes, and the control of the camera exposure can be satisfied by using the current exposure table if the range of the relative aperture value does not change. For example, the diaphragm number range is changed from F2.8-F16 (including 6 adjustable gears, the relative diaphragm value range is 1-1281) to F4.0-F22 (including 6 adjustable gears, the relative diaphragm value range is 1-1281), although the diaphragm number range is changed, the relative diaphragm value range is not changed, and the camera exposure can be controlled by using the current exposure table. For another example, if the diaphragm number range is changed from F2.8 to F16 (including 6 adjustable stages, the relative aperture value range is 1 to 1281) to F2 to F22 (including 8 adjustable stages, the relative aperture value range is 1 to 1793), the diaphragm number range is changed, and the relative aperture value range is also changed, it is necessary to use a new exposure table for exposure control.
In operation S240, the exposure table is updated. According to the embodiment of the invention, when the range of the relative aperture value is changed, the change of the callable gear is indicated, so that the callable gear can be selected by new adjustment under different brightness of ambient light, and the exposure table needs to be updated. For example, as shown in table 3, which represents an exposure table corresponding to a relative aperture value range including 6 callable stages, when the relative aperture value range is changed to be larger or smaller, the exposure table needs to be updated to accommodate the selection of a different number of callable stages.
For example, when the lens a (F2.8 to F16, exposure time 8s to 1/8000s, and sensitivity 12800 to 100) is replaced with the lens C (F2.8 to F11, exposure time 8s to 1/8000s, and sensitivity 12800 to 100), the relative aperture value among the exposure parameters of the lens C can be selected in 5 steps, for example, as shown in the exposure table in table 4.
TABLE 4
| Brightness of ambient light | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Relative aperture value | 1 | 1 | 257 | 257 | 513 | 513 | 513 | 769 | 769 | 1025 |
| Exposure time(s) | 8 | 1/15 | 1/15 | 1/15 | 1/15 | 1/500 | 1/500 | 1/500 | 1/8000 | 1/8000 |
| Sensitivity of light | 12800 | 12800 | 12800 | 400 | 400 | 400 | 100 | 100 | 100 | 100 |
According to the embodiment of the present invention, the same exposure table can be used for the lenses having the same relative aperture value range, for example, the relative aperture value range is 1-1025, and the exposure table can be used for all the lenses having 5 adjustable steps in the aperture value range. The exposure tables of the lenses with different relative aperture value ranges should be changed relatively, for example, the exposure tables with relative aperture value ranges of 1-1281 shown in Table 3 are different from the exposure tables with relative aperture value ranges of 1-1025 shown in Table 4.
It will be understood by those skilled in the art that the present invention is not limited to the specific values exemplified above, and that any combination of exposure parameters that meets the exposure criteria may be found in the exposure table. When the range of the relative aperture value is larger, the number of the gears of the adjustable diaphragm number is correspondingly larger, and the adjustment of the aperture can be correspondingly increased in the exposure table. When the range of the relative aperture value is small, the number of the adjustable aperture number is relatively small, and the exposure time and the adjustment of the sensitivity can be correspondingly increased in the exposure table. The present invention is not limited to a specific combination of exposure parameters, and any combination of exposure parameters that can satisfy the ambient light level can be set up in the exposure table.
In the embodiment of the present invention, a plurality of exposure tables with different relative aperture value ranges may be established, and when the lens of the camera is switched or the focal length of the zoom lens is changed, the called exposure table may be selected by determining the relative aperture value range. Or when the lens of the camera is switched or the focal length of the zoom lens is changed, refreshing the current exposure table according to the current lens information obtained by detection and a preset rule.
According to the scheme of the embodiment of the invention, the exposure table is established by replacing the diaphragm number with the relative diaphragm value, and various lenses with the same relative diaphragm value range can use the same exposure table, so that the number of the exposure tables in the camera is reduced, and the memory pressure is relieved. When the range of the relative aperture value changes, the exposure table can be refreshed according to the rule corresponding to the preset range of the relative aperture value, so that a new exposure table can be quickly established to adapt to the current lens. When the relative aperture value range changes, the corresponding exposure table can be directly called from a plurality of established exposure tables with different relative aperture value ranges for exposure control, so that the aim of quickly controlling exposure can be fulfilled.
Fig. 3 schematically shows a block diagram of an automatic exposure apparatus for a camera according to an embodiment of the present invention.
As shown in fig. 3, the automatic exposure apparatus includes a storage unit 310, a brightness detection unit 320, a control unit 330, a lens detection unit 340, and an exposure table generation unit 350. The automatic exposure apparatus may perform the method described above with reference to fig. 1 to 2 to implement automatic exposure of the camera.
Specifically, the storage unit 310 is configured to store an exposure table, where the exposure table records exposure parameters corresponding to different ambient light intensities, the exposure parameters include a relative aperture value, the relative aperture value is a function of an f-number, and a second derivative of the function is smaller than 0. According to an embodiment of the present invention, the storage unit 310 may perform, for example, operation S110 described above with reference to fig. 1.
The brightness detection unit 320 is used for detecting the brightness of the current environment. According to an embodiment of the present invention, the luminance detecting unit 320 may perform, for example, operation S120 described above with reference to fig. 1. Preferably, the brightness detection unit 320 employs a CMOS sensor. In a specific embodiment, a CMOS sensor of a camera may be used to double as a luminance detection unit to simplify the device structure and reduce the weight and cost.
The control unit 330 is configured to query the exposure table for an exposure parameter corresponding to the brightness of the current ambient light, and adjust an exposure element of the camera to satisfy the exposure parameter. According to an embodiment of the present invention, the control unit 330 may perform, for example, operation S130 described above with reference to fig. 1.
Specifically, the control unit 330 adjusts an exposure element of the camera according to the f-number after converting the relative f-number into the f-number.
The lens detection unit 340 is configured to detect whether a range of the relative aperture value of the lens of the camera changes. According to an embodiment of the present invention, the lens detection unit 340 may perform operations S210 to S230 described above with reference to fig. 2, for example.
The exposure table generation unit 350 is configured to recalculate the relative aperture value in the exposure table when the range of the relative aperture value is changed. According to an embodiment of the present invention, the exposure table generating unit 350 may perform, for example, operation S240 described above with reference to fig. 2.
It is to be understood that the storage unit 310, the brightness detection unit 320, the control unit 330, the lens detection unit 340, and the exposure table generation unit 350 may be combined in one module to be implemented, or any one of them may be split into a plurality of modules. Alternatively, at least part of the functionality of one or more of these modules may be combined with at least part of the functionality of the other modules and implemented in one module. According to an embodiment of the present invention, at least one of the storage unit 310, the brightness detection unit 320, the control unit 330, the lens detection unit 340, and the exposure table generation unit 350 may be at least partially implemented as a hardware circuit, such as a Field Programmable Gate Array (FPGA), a Programmable Logic Array (PLA), a system on a chip, a system on a substrate, a system on a package, an Application Specific Integrated Circuit (ASIC), or may be implemented in hardware or firmware in any other reasonable manner of integrating or packaging a circuit, or implemented in a suitable combination of three implementations of software, hardware, and firmware. Alternatively, at least one of the storage unit 310, the brightness detection unit 320, the control unit 330, the lens detection unit 340, and the exposure table generation unit 350 may be at least partially implemented as a computer program module, and when the program is executed by a computer, the function of the corresponding module may be performed.
Fig. 4 schematically shows a block diagram of a camera 400 according to an embodiment of the invention.
As shown in fig. 4, the camera 400 includes the automatic exposure apparatus described above with reference to fig. 3. According to the embodiment of the invention, the camera 400 can use an automatic exposure device to realize automatic control of exposure under different ambient light brightness. The camera generally includes a body and a lens, which may be integral or removable. The automatic exposure device is usually located in the body, but may be partially located in the lens, and the position of the automatic exposure device is not limited in the present invention. The camera also comprises an exposure element which can be positioned on the body and also can be positioned on the lens. The exposure element comprises at least one of a shutter, an aperture, and an ISO regulator.
In summary, the present invention uses the relative aperture value instead of the f-number as the exposure parameter to establish the exposure table, and the same exposure table can be used for all the lenses with the same relative aperture value range, so as to reduce the number of the exposure tables in the camera and relieve the memory pressure. When the range of the relative aperture value changes, the exposure table can be refreshed according to the rule corresponding to the preset range of the relative aperture value, so that a new exposure table can be quickly established to adapt to the current lens. When the relative aperture value range changes, the corresponding exposure table can be directly called from a plurality of established exposure tables with different relative aperture value ranges for exposure control, so that the aim of quickly controlling exposure can be fulfilled.
The above-described methods, modules, and methods according to embodiments of the present invention may be implemented by a computing-capable electronic device executing software containing computer instructions. The system may include storage devices to implement the various storage described above. The computing-capable electronic device may include, but is not limited to, a general-purpose processor, a digital signal processor, a special-purpose processor, a reconfigurable processor, and the like capable of executing computer instructions. Execution of such instructions causes the electronic device to be configured to perform the operations described above in accordance with the present invention. The methods and/or modules described above may be implemented in one electronic device, or may be implemented in different electronic devices.
Embodiments of the present invention use software that may be stored in the form of volatile memory or non-volatile storage (such as storage devices like ROM), whether erasable or rewritable, or in the form of memory (e.g., RAM, memory chips, devices or integrated circuits), or on optically or magnetically readable media (e.g., CD, DVD, magnetic disk or tape, etc.). It should be appreciated that the storage devices and storage media are embodiments of machine-readable storage suitable for storing one or more programs that include instructions, which when executed, implement embodiments of the present invention. Further, these programs may be delivered electronically via any medium (e.g., communication signals carried via a wired connection or a wireless connection), and embodiments suitably include these programs.
While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. Accordingly, the scope of the present invention should not be limited to the above-described embodiments, but should be defined not only by the appended claims, but also by equivalents thereof.
Claims (21)
1. An auto-exposure method for a camera, comprising:
detecting the brightness of the current ambient light;
inquiring an exposure parameter corresponding to the brightness of the current ambient light in an exposure table, wherein the exposure parameter comprises a relative aperture value, the relative aperture value and the current diaphragm number of a lens of the camera form a preset relation, and when the diaphragm number ranges of a first lens and a second lens are different but the relative aperture value ranges of the first lens and the second lens are the same, the exposure table corresponding to the first lens and the exposure table corresponding to the second lens are the same;
and adjusting an exposure element in the camera according to the exposure parameter.
2. The automatic exposure method for a camera according to claim 1, wherein adjusting an exposure element in the camera according to the exposure parameter comprises:
converting the relative aperture value into an f-number;
and adjusting an exposure element in the camera according to the f-number.
3. The automatic exposure method for a camera according to claim 1, wherein the predetermined relationship is a linear relationship of the relative aperture value and a logarithm of an f-number.
4. The automatic exposure method for a camera according to claim 3, wherein the relative aperture value is linear with a base-2 logarithm of an f-number.
5. The automatic exposure method for a camera according to claim 4, wherein the relative aperture value is represented by the following formula:
wherein LI denotes a relative aperture value, Fnum denotes an f-number of a lens in the camera, Fmax denotes an f-number of a maximum aperture of a lens in the camera, and LDR denotes a number of parts by which a first-gear f-number range of the lens of the camera is equally divided.
6. The automatic exposure method for a camera according to claim 1, further comprising: detecting whether the range of the relative aperture value of the lens of the camera changes or not, and updating an exposure table if the range of the relative aperture value exceeds the range of the relative aperture value in the exposure table.
7. An automatic exposure apparatus for a camera, comprising:
the camera comprises a storage unit, a processing unit and a control unit, wherein the storage unit is used for storing an exposure table, the exposure table records exposure parameters corresponding to different ambient light brightness, the exposure parameters comprise relative aperture values, the relative aperture values are functions of the current diaphragm number of a lens of the camera, and when the diaphragm number ranges of a first lens and a second lens are different but the relative aperture value ranges of the first lens and the second lens are the same, the exposure table corresponding to the first lens is the same as the exposure table corresponding to the second lens;
a brightness detection unit for detecting brightness of the current ambient light;
and the control unit is used for inquiring the exposure parameters corresponding to the brightness of the current ambient light in the exposure table and adjusting the exposure element of the camera to meet the exposure parameters.
8. The automatic exposure apparatus for a camera according to claim 7, wherein the brightness detection unit is a CMOS sensor.
9. The automatic exposure apparatus for camera according to claim 7, wherein the control unit is further configured to adjust an exposure element of the camera according to an f-number after converting the relative aperture value into the f-number.
10. The automatic exposure apparatus for a camera according to claim 7, wherein the relative aperture value is linear with a logarithm of an f-number.
11. The automatic exposure apparatus for a camera according to claim 10, wherein the relative aperture value is linear with a base-2 logarithm of an f-number.
12. The automatic exposure apparatus for a camera according to claim 11, wherein the relative aperture value is expressed by the following formula:
wherein LI denotes a relative aperture value, Fnum denotes an f-number of a lens in the camera, Fmax denotes an f-number of a maximum aperture of a lens in the camera, and LDR denotes a number of parts by which a first-gear f-number range of the lens of the camera is equally divided.
13. The automatic exposure apparatus for a camera according to claim 7, wherein the camera further comprises:
a lens detection unit for detecting whether a range of the relative aperture value of a lens of the camera changes,
and the exposure table generating unit is used for updating the exposure table when the range of the relative aperture value exceeds the range of the relative aperture value in the exposure table.
14. A camera comprising a body, a lens mounted to the body, and an automatic exposure device mounted to the body or the lens, the exposure device comprising:
the camera comprises a storage unit, a processing unit and a control unit, wherein the storage unit is used for storing an exposure table, the exposure table records exposure parameters corresponding to different ambient light brightness, the exposure parameters comprise relative aperture values, the relative aperture values are functions of the current diaphragm number of a lens of the camera, and when the diaphragm number ranges of a first lens and a second lens are different but the relative aperture value ranges of the first lens and the second lens are the same, the exposure table corresponding to the first lens is the same as the exposure table corresponding to the second lens;
a brightness detection unit for detecting brightness of the current ambient light;
and the control unit is used for inquiring the exposure parameters corresponding to the brightness of the current ambient light in the exposure table and adjusting the exposure element of the camera to meet the exposure parameters.
15. The camera of claim 14, wherein the brightness detection unit is a CMOS sensor.
16. The camera of claim 14, wherein the exposure element comprises at least one of a shutter, an aperture, and an ISO regulator.
17. The camera as claimed in claim 14, wherein the control unit is further configured to adjust an exposure component of the camera according to an f-number after converting the relative f-number into the f-number.
18. The camera of claim 14, wherein the relative aperture value is linear with the logarithm of the f-number.
19. The camera of claim 18, wherein the relative aperture value is linear with a base 2 logarithm of an f-number.
20. The camera of claim 19, wherein the relative aperture value is represented by the formula:
wherein LI denotes a relative aperture value, Fnum denotes an f-number of a lens in the camera, Fmax denotes an f-number of a maximum aperture of a lens in the camera, and LDR denotes a number of parts by which a first-gear f-number range of the lens of the camera is equally divided.
21. The camera of claim 14, further comprising:
a lens detection unit for detecting whether a range of the relative aperture value of a lens of the camera changes,
and the exposure table generating unit is used for updating the exposure table when the range of the relative aperture value exceeds the range of the relative aperture value in the exposure table.
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| PCT/CN2017/084903 WO2018209650A1 (en) | 2017-05-18 | 2017-05-18 | Automatic exposure method and device for camera |
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| CN109413336A (en) * | 2018-12-27 | 2019-03-01 | 北京旷视科技有限公司 | Image pickup method, device, electronic equipment and computer readable storage medium |
| CN113271433A (en) * | 2020-02-17 | 2021-08-17 | 群光电子股份有限公司 | Monitoring device and image capturing method |
| CN111654641B (en) * | 2020-07-20 | 2021-07-13 | 浙江大学 | Airborne camera exposure parameter adjusting method and system |
| CN114339060A (en) * | 2020-09-30 | 2022-04-12 | 宇龙计算机通信科技(深圳)有限公司 | Exposure adjusting method and device, storage medium and electronic equipment |
| CN114520870B (en) * | 2020-11-20 | 2023-06-20 | 华为技术有限公司 | Display method and terminal |
| CN116074634B (en) * | 2022-05-27 | 2023-11-14 | 荣耀终端有限公司 | Exposure parameter determination method and device |
| CN115103130B (en) * | 2022-08-24 | 2023-05-02 | 龙旗电子(惠州)有限公司 | Aperture control method, device, equipment and storage medium |
| CN117135467A (en) * | 2023-02-23 | 2023-11-28 | 荣耀终端有限公司 | Image processing method and electronic equipment |
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| CN108702459A (en) | 2018-10-23 |
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