CN106851122B - Calibration method and device for automatic exposure parameters based on double-camera system - Google Patents
Calibration method and device for automatic exposure parameters based on double-camera system Download PDFInfo
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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
- H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
Abstract
The embodiment of the invention discloses a method and a device for calibrating automatic exposure parameters based on a double-camera system. Wherein, the method comprises the following steps: acquiring a first image and a second image of a target object based on a first camera and a second camera respectively; acquiring a common view field of the first camera and the second camera, and respectively counting a first brightness value and a second brightness value of a pixel region in the common view field in the first image and the second image; adjusting exposure parameters so that the first brightness value and the second brightness value are the same and reach at least one preset target brightness value respectively, and recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness value respectively. According to the technical scheme of the embodiment of the invention, the inconsistency of the brightness response of the first camera and the second camera in the double-shot system is compensated, and the double-shot exposure is cooperatively controlled by using the common statistic of the images of the double-shot system, so that the brightness consistency of the double-shot system is realized.
Description
Technical Field
The embodiment of the invention relates to the technical field of electronic equipment, in particular to an automatic exposure method and device based on a double-camera system.
Background
A dual-camera system (hereinafter referred to as "dual camera") gradually becomes a standard configuration of a smart phone due to its powerful functions such as background blurring, rear focusing, optical zooming, and dark state enhancement.
The matching algorithm is a main factor influencing the precision and the effect of the double-shot algorithm. The matching algorithm is a searching algorithm based on the gray level, color and definition of the image, and the matching algorithm performs the matching of the two-shot view according to the three dimensions of the image evaluation. Only if the corresponding relation of the pixels between the two images is accurately found out through a matching algorithm, the depth calculation, fusion enhancement or field splicing can be carried out by utilizing the cross information of the two images at the same time, and any double-shot effect cannot be mentioned without high-precision image matching. Therefore, the consistency of the brightness of the bi-shot images can greatly affect the performance and effect of the bi-shot algorithm.
The prior art employs an auto-exposure algorithm to maintain brightness consistency. The automatic exposure algorithm is the most important algorithm influencing the brightness of an image, and the existing automatic exposure algorithm sets different exposure parameters for pixel regions with different brightness conditions in the image, so that the brightness of the overall image tends to be consistent comprehensively.
Since the difference in the field angles of the two image pickup units in the two-shot system is not taken into consideration, if a target object having a luminance different from that of the common field exists in the unique fields of the two image pickup units, a deviation of statistical data is caused, and finally a difference in the convergence target is exposed. When the exposure parameters determined according to the method are applied to the double-shot public view field, the brightness of the double-shot public view field has larger deviation, and the double-shot public view field cannot be matched based on the brightness. In addition, since no consideration is given to the difference between the left and right of the double camera module, even if the same exposure parameters are used, completely different image luminances can be obtained without correction.
Disclosure of Invention
The embodiment of the invention provides an automatic exposure method and device based on a double-camera system, which are used for ensuring the consistency of the brightness of double-shot images.
In a first aspect, an embodiment of the present invention provides a method for calibrating an automatic exposure parameter based on a dual-camera system, where the method includes:
acquiring a first image and a second image of a target object based on a first camera and a second camera respectively;
acquiring a common view field of the first camera and the second camera, and respectively counting a first brightness value and a second brightness value of a pixel region in the common view field in the first image and the second image;
adjusting exposure parameters so that the first brightness value and the second brightness value are the same and reach at least one preset target brightness value respectively, and recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness value respectively.
In a second aspect, an embodiment of the present invention further provides a calibration apparatus for automatic exposure parameters based on a dual-camera system, where the apparatus includes:
the image acquisition module is used for acquiring a first image and a second image of the target object based on the first camera and the second camera respectively;
the brightness value counting module is used for acquiring a common view field of the first camera and the second camera and respectively counting a first brightness value and a second brightness value of a pixel area positioned in the common view field in the first image and the second image;
and the exposure parameter recording module is used for adjusting exposure parameters so that the first brightness value and the second brightness value are the same and reach at least one preset target brightness value respectively, and recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness values respectively.
According to the technical scheme of the embodiment of the invention, the public view field of the first camera and the second camera is obtained, the double-shot exposure is cooperatively controlled by utilizing the common statistic of the images of the double-shot system in the public view field, so that the problems of brightness deviation or unmatched brightness caused by the unique view field of the first camera and the second camera are solved, the exposure parameters of the first camera and the second camera reaching the same preset target brightness values are recorded, the brightness response inconsistency of the first camera and the second camera in the double-shot system is compensated by adjusting the exposure parameters, the brightness consistency of the first camera and the second camera in the double-shot system is realized, and the imaging effect is optimized.
Drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, a brief description is given below of the drawings used in describing the embodiments. It should be clear that the described figures are only views of some of the embodiments of the invention to be described, not all, and that for a person skilled in the art, other figures can be derived from these figures without inventive effort.
Fig. 1 is a schematic flowchart of a calibration method for automatic exposure parameters based on a dual-camera system according to a first embodiment of the present invention;
fig. 2A is a schematic flowchart of a calibration method for automatic exposure parameters based on a dual-camera system according to a second embodiment of the present invention;
FIG. 2B is a schematic diagram illustrating a method for determining a common field of view according to a second embodiment of the present invention;
FIG. 2C is a schematic equivalent of the computational principle of FIG. 2B;
fig. 2D is a schematic diagram illustrating an example of a calibration method for automatic exposure parameters based on a dual-camera system according to a second embodiment of the present invention;
fig. 3 is a schematic structural diagram of an automatic exposure parameter calibration apparatus based on a dual-camera system according to a third embodiment of the present invention.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart may describe the steps as a sequential process, many of the steps can be performed in parallel, concurrently or simultaneously. In addition, the order of the steps may be rearranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, and the like.
Example one
Fig. 1 is a schematic flowchart of a calibration method for automatic exposure parameters based on a dual-camera system according to an embodiment of the present invention, where the method can be executed by a calibration apparatus for automatic exposure parameters based on a dual-camera system, and the apparatus can be implemented in a hardware and/or software manner, and can generally be independently configured in a user terminal to implement the method according to this embodiment.
The method of the embodiment specifically comprises the following steps:
and S110, acquiring a first image and a second image of the target object based on the first camera and the second camera respectively.
The target object may be the whole scene area photographed, or may be a partial object or a single object in a multi-object scene, or may be a part of a single object. For example, the target object may be understood as a focus exposure object based on images with a depth effect captured by the first camera and the second camera.
Considering that the image of the shooting scene area is easily interfered by factors such as ambient light, effective shooting distance, actual shooting distance, size of the shot object and the like, a gray scale card, such as a monochrome gray scale card and a standard color-changing gray scale card, can be adopted as the target object. Further, in order to better acquire images, a gray scale card with uniformity greater than a preset threshold value can be adopted. Moreover, the image can be ensured to be clear by adopting a light source which meets the brightness requirement, adjusting the distance from the focal length of the camera to the gray scale card and the like.
In a dual-camera system, when an image of a target object is acquired, a first camera and a second camera are required to respectively adjust various parameters based on their own attributes to ensure the image to be clear, so that a first image of the target object is acquired based on the first camera, and a second image of the target object is acquired based on the second camera.
S120, obtaining a common view field of the first camera and the second camera, and respectively counting a first brightness value and a second brightness value of a pixel area of the common view field in the first image and the second image.
Acquiring the common field of view of the first and second cameras may be acquiring all or part of the common field of view of the first and second cameras. Specifically, a coordinate system may be established, and the common view field may be determined by the position coordinates of the start and the end of the common view field of the first camera and the second camera; or the proportion of the common field of view in all the field of view areas covered by the first camera and the second camera can be determined through length or proportion calculation.
Optionally, the common view field of the first camera and the second camera is obtained, and specifically, the common view field of the first camera and the second camera is determined according to a distance between the first camera and the second camera in the current scene, an effective shooting distance, and a field angle.
The pixel region located in the common field of view may be the entire common field of view or a partial region of the common field of view. That is, the first luminance value and the second luminance value of the pixel region of the common field of view in the first image and the second image are respectively counted, the first luminance value and the second luminance value of the entire pixel region of the common field of view in the first image and the second image are respectively counted, or the first luminance value and the second luminance value of the partial pixel region of the common field of view in the first image and the second image are respectively counted.
S130, adjusting exposure parameters to enable the first brightness value and the second brightness value to be the same and respectively reach at least one preset target brightness value, and respectively recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness values.
Illustratively, the exposure parameters may include, but are not limited to, exposure line and gain, and may include other parameters that affect camera brightness.
Specifically, the exposure parameters of the first camera and the second camera corresponding to the preset target brightness values respectively can be counted under the preset target brightness values. Optionally, the current preset target brightness value is selected, the exposure parameters of the first camera and the second camera may be respectively adjusted, so that the first brightness value and the second brightness value are the same, and both the first brightness value and the second brightness value reach the current preset target brightness value, and the exposure parameters of the first camera and the second camera corresponding to the current preset target brightness value are respectively recorded. Or, the exposure parameters corresponding to the preset target brightness values of the first camera may be recorded respectively, and similarly, the exposure parameters corresponding to the preset target brightness values of the second camera may be recorded respectively, and then counted, summarized and recorded respectively in the same preset target brightness values, and the exposure parameters corresponding to the first camera and the second camera may be recorded respectively.
At least one of them may be one, two, three or more, and is not limited herein. In this embodiment, a plurality of preset target brightness values may be employed. The preset target brightness value can be set by the user, or can be set by default in a background through a preset rule or algorithm.
Optionally, in order to facilitate management and query, the preset target brightness values and the exposure parameters of the first camera and the second camera corresponding to the preset target brightness values may be recorded in a form of a table. Further, the method can also be stored under a preset path so as to be convenient for direct query and acquisition.
According to the technical scheme of the embodiment of the invention, the public view field of the first camera and the second camera is obtained, the double-shot exposure is cooperatively controlled by utilizing the common statistic of the images of the double-shot system in the public view field, so that the problems of brightness deviation or unmatched brightness caused by the unique view field of the first camera and the second camera are solved, the exposure parameters of the first camera and the second camera reaching the same preset target brightness values are recorded, the brightness response inconsistency of the first camera and the second camera in the double-shot system is compensated by adjusting the exposure parameters, the brightness consistency of the first camera and the second camera in the double-shot system is realized, and the imaging effect is optimized.
Example two
Fig. 2A is a schematic flow chart of a calibration method for automatic exposure parameters based on a dual-camera system according to a second embodiment of the present invention, as shown in fig. 2A, in this embodiment, on the basis of the foregoing embodiments, optionally, the acquiring a common field of view of the first camera and the second camera includes: and determining the common field of view of the first camera and the second camera according to the distance between the first camera and the second camera, the effective shooting distance and the field angle in the current scene.
On the basis of the above technical solutions, the calibration method for automatic exposure parameters based on a dual-camera system according to this embodiment may further include: inquiring and acquiring exposure parameters corresponding to the first camera and the second camera according to the current target brightness value of the current public view field; acquiring a third image and a fourth image of the current object based on the first camera and the second camera respectively by adopting the exposure parameters; the current common view field is a common view field of the first camera and the second camera in the current scene; and fusing the third image and the fourth image to obtain a final image.
The method of the embodiment may specifically include:
s210, acquiring a first image and a second image of the target object based on the first camera and the second camera respectively.
S220, determining a common view field of the first camera and the second camera according to the distance between the first camera and the second camera, the effective shooting distance and the view field angle in the current scene.
For example, the distance between the first camera and the second camera, the effective shooting distance and the field angle in the current scene can be acquired, and the common field of view of the first camera and the second camera is determined by adopting a geometric method. In this embodiment, the proportion of the common view field, the coordinates of the left shooting start and end position, the coordinates of the right shooting start and end position, and the like can also be determined according to a preset coordinate system.
In the operation, the effective image capturing distance d of the double shot can be estimated according to the application scene of the double shot, wherein the effective image capturing distance is related to the mechanical parameters, the internal algorithm, the imaging effect and other factors of the double shot. The specific algorithm of the effective shooting distance may be determined according to the method in the prior art, and is not described herein again. Furthermore, the actual shooting distance within the effective shooting distance range can be calculated, and then the common view field of the first camera and the second camera is determined by adopting a geometric method according to the distance between the first camera and the second camera in the current scene, the effective shooting distance and the view field angle. Illustratively, the actual shooting distance within the effective shooting distance range may be calculated according to an existing shooting distance calculation method, for example, a shooting distance (i.e., object distance) algorithm configured in a shooting apparatus employing a two-shot system.
Fig. 2B is a schematic diagram illustrating a method for determining a common viewing field according to an embodiment of the present invention, and fig. 2C is an equivalent schematic diagram illustrating a calculation principle of fig. 2B, as shown in fig. 2B and fig. 2C, the first camera and the second camera are respectively represented by a left shot and a right shot, since the widths of the cameras are often much smaller than the length of the shooting distance and the width of the shooting scene, they can be ignored in the calculation and are approximately regarded as a point, which is respectively represented as a point a and a point B in fig. 2C, the angle of view ∠ CAM of the left shot a, the angle of view ∠ EBN of the right shot B, and the actual shooting distance d are known1And camera pitch d2(i.e., the width between the line segments AB). The actual shooting distance is known as d1I.e. CF ═ d1And then EG DA HB CF d1. In the vertical direction, the length of the common view field is the same as that of the left-shooting unique view field and that of the right-shooting unique view field, so that the length of EM is only needed to be calculated for determining the common view field.
For example, in the case of the pan shot, the viewing angle ∠ CAM and the viewing angle characteristic of the pan shot a can be known, and in the triangular ACD, CD (AD) tan (∠ CAM/2) d (d) can be obtained1Tan (∠ CAM/2), and in triangular EGB, GB ═ EG ═ cot (90 ° - ∠ EBN/2) ═ d can be obtained1Cot (90 ° - ∠ EBN/2), and further according to ED ═ EH-DH ═ GB-AB ═ d1*cot(90°-∠EBN/2)-d2The ED is calculated. In the same way, the HM in the right-handed view field can be calculated, and finally, the EM is calculated according to the EM ED + BH + HM, where DH AB is the common view field.
Further, the proportion of the common field of view in the whole field of view covered by the left-hand shooting and the right-hand shooting can be determined, the starting position and the ending position of the common field of view in the whole field of view covered by the left-hand shooting and the right-hand shooting can be determined according to a preset coordinate system and the coordinates, and the starting position and the ending position of the left-hand shooting field of view, the right-hand shooting field of view, the unique left-hand shooting field of view and the unique right-hand shooting field of view can be determined.
It should be noted that the method for calculating the common field of view shown in the above steps is only used for explaining a specific method for determining the common field of view, and is not limited, and it is within the scope of the present invention to calculate the common field of view by other means.
And S230, respectively counting a first brightness value and a second brightness value of a pixel region of the first image and the second image in the common field of view.
S240, adjusting exposure parameters to enable the first brightness value and the second brightness value to be the same and respectively reach at least one preset target brightness value, and respectively recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness values.
And S250, inquiring and acquiring exposure parameters corresponding to the first camera and the second camera according to the current target brightness value of the current public view field.
For example, the current target brightness value may be set by the user according to actual needs, or may be a brightness value suitable for being viewed by human eyes calculated according to a background default setting algorithm (for example, in combination with brightness, color, and the like of the current shooting scene), that is, a default brightness value. In the operation, in the recorded exposure parameters of the first camera and the second camera corresponding to each preset target brightness value, the exposure parameters corresponding to the first camera and the second camera corresponding to the current target brightness value of the previous public view field are inquired and obtained and used as execution parameters, so that the first image and the second image respectively obtained by the first camera and the second camera reach the current target brightness. And the current common view field is the common view field of the first camera and the second camera in the current scene.
According to the technical scheme, the brightness consistency of the first image and the second image is guaranteed, the exposure parameters are determined in a query mode, and the exposure response speed is improved.
And S260, acquiring a third image and a fourth image of the current object based on the first camera and the second camera respectively by adopting the exposure parameters.
In this operation, the process of acquiring images is similar to S110 and S210, except that the exposure parameter of the first camera may be adjusted to be the queried exposure parameter, a third image of the current object is acquired based on the first camera, and simultaneously, the exposure parameter of the second camera is adjusted to be the queried exposure parameter, and a fourth image of the current object is acquired based on the second camera.
It can be understood that, since the current target brightness value is preset, the current actual brightness values of the third image and the fourth image of the current object obtained based on the current target brightness value should theoretically be consistent, which ensures the consistency of the brightness of the third image and the fourth image in the execution process.
And S270, fusing the third image and the fourth image to obtain a final image.
In this embodiment, in order to further ensure the brightness of the final image of the dual-camera system, the fusing the third image and the fourth image to obtain the final image may specifically include: counting the current actual brightness value of the third image and the fourth image in the current common field of view; judging whether the current actual brightness value is within a preset brightness tolerance range; if so, fusing the third image and the fourth image to obtain a final image; if not, after the current actual brightness value is corrected to the current target brightness value, the third image and the fourth image are fused to obtain a final image. Specifically, in the embodiment of the present invention, the third image and the fourth image may be fused by using one or more existing image fusion methods, which are not described herein again.
For example, the preset luminance tolerance range may be used to represent a tolerance between the current actual luminance value of the third image and the current actual luminance value of the fourth image and the current target luminance value, respectively, and may also be used to represent a tolerance between the current actual luminance value of the third image and the current actual luminance value of the fourth image. Further, the preset brightness tolerance range may be a specific brightness difference, or may be a tolerance ratio, such as a percentage, a dial ratio, etc., that varies with the current actual brightness value.
Wherein the current reality is judgedWhether the brightness value is within the preset brightness tolerance range or not can be specifically that the current actual brightness value of the third image is compared with the current brightness value of the fourth image; or comparing the current actual brightness value of the third image or the fourth image with the current actual brightness value of the fourth image or the third image by adding or subtracting the maximum brightness tolerance value to obtain a tolerance brightness value. The maximum tolerance value is understood to be the maximum allowable tolerance value, for example, the tolerance range is 0-10 or 0-10%, and the maximum tolerance value is 10 or 10% of the current actual brightness value of the third image or the fourth image. Illustratively, the smaller of the current actual brightness value of the third image and the current actual brightness value of the fourth image is taken as LaAfter adding the maximum tolerance value, it is recorded as the brightness value LbRecording the larger current actual brightness value of the third image and the current actual brightness value of the fourth image as LcIs prepared by mixing La、LbAnd LcMaking a comparison if La≤Lb≤LcIf the current actual brightness value is within the preset brightness tolerance range, fusing the third image and the fourth image to obtain a final image; otherwise, after the current actual brightness value is corrected to the current target brightness value, the third image and the fourth image are fused to obtain a final image.
In this embodiment, the specific step of correcting the current actual brightness value to the current target brightness value may be to compare the current actual brightness value of the third image and the current actual brightness value of the fourth image with a preset current target brightness value, obtain the third image and the fourth image again by adjusting the exposure parameter, and calculate the current actual brightness value of the images until the adjusted current actual brightness value is within a preset brightness tolerance range; or, taking one of the current actual brightness value of the third image and the current actual brightness value of the fourth image as a reference, and adjusting the exposure parameter of the first camera or the second camera so that one of the current actual brightness value of the third image and the current actual brightness value of the fourth image approaches to the other value until the adjusted current actual brightness value is within the preset brightness tolerance range. For example, a main camera and a sub-camera in the first camera and the second camera respectively are determined, and then the exposure parameter of the sub-camera is adjusted by taking the current actual brightness value of the image acquired by the main camera as a reference, so that the current actual brightness value of the image acquired by the sub-camera is within the brightness tolerance range.
According to the technical scheme, the public view field of the first camera and the public view field of the second camera are obtained, exposure parameter calibration is carried out based on the brightness statistics that the first image and the second image are located in the public view field, further, recorded exposure parameters are inquired, the brightness values of the third image and the fourth image are consistent, whether the current actual brightness value is within the preset brightness tolerance range or not is further determined according to the preset brightness tolerance range, it is better guaranteed that the current actual brightness value of the third image and the current actual brightness value of the fourth image meet the requirement of brightness consistency, the brightness consistency is guaranteed in the execution process, further verification is carried out through the preset brightness tolerance range, the brightness consistency of the third image and the fourth image used for fusion is better guaranteed, and the imaging effect of the final image after fusion is effectively improved.
Fig. 2D is a schematic diagram of an example of a calibration method for automatic exposure parameters based on a dual-camera system according to a second embodiment of the present invention. As shown in fig. 2D, the method includes:
1. calibrating double-shot exposure parameters:
in this example, the calibrated exposure parameters are exposure Line (Line Counter) and Gain (Gain). The first camera and the second camera are respectively represented by left shooting and right shooting according to the position relation. And a monochrome gray scale card is selected for calibration, so that the consistency of double shot exposure lines and gain response is ensured.
Specifically, a uniform monochromatic gray-scale card may be used as a target, preferably a gray-scale card uniformity > 95%, and then a D65 light source with a brightness of 500lux may be used. In order to ensure the imaging effect, the gray scale card or the double cameras can be adjusted to enable the gray scale card to be located in the center of the field of view of the double cameras, furthermore, the proportion of the field of view occupied by the gray scale card is more than 80%, the distance from the focal length of the cameras to the gray scale card is further adjusted to ensure the image to be clear, and finally, the exposure parameters are adjusted to enable the double cameras to simultaneously reach different target brightness values, namely, the brightness values expected to be reached, the exposure rows and gains shot left and right are recorded to form a query table. Note that the exposure parameters recorded are exposure parameters for both the left shot and the right shot when the same target luminance value is reached. For example, when the target brightness value is 50, exposure parameters for the left shot and the right shot are recorded, respectively. It is understood that the target brightness value may be a default brightness value that is desired to be achieved, or a plurality of different target brightness values may be set by the user according to actual needs.
2. And (3) brightness statistical region correction:
according to the actual object distance (i.e., the actual shooting distance) in each scene within the effective shooting distance d, parameters such as the size of the common view field and the initial position in the current scene of the double shooting are determined, and a specific algorithm can be referred to S220. Furthermore, the luminance statistic area of the first image and the luminance statistic area of the second image are both set as a common field of view, that is, only the luminance of the common field of view is counted in the actual luminance statistic process.
3. The independent auto-exposure algorithm starts:
and respectively calculating the exposure line and the gain of the left shot and the right shot by adopting an exposure tracking algorithm the same as that of the single shot and distinguishing the brightness statistical region as a common field region.
4. Left and right shooting exposure parameter correction:
specifically, the table lookup correction is performed according to the left and right exposure lines and gains calculated in step 3 and the lookup table recorded in step 1. For example, a main camera and a sub camera in left shooting and right shooting can be determined, then the main camera is used as a main camera, a target brightness value corresponding to an exposure parameter of the main camera and an exposure parameter of the sub camera corresponding to the target brightness value in a query table are queried, and the exposure parameter of the sub camera is adjusted, so that the brightness of the main camera is consistent with that of the sub camera.
5. Cross checking and correcting parameters;
firstly, calculating actual brightness according to the exposure rows and the gain lookup table obtained in the step 4, respectively obtaining a left-shot actual brightness LuminanceLeft and a right-shot actual brightness LuminanceRight, and assigning a larger value to LBig and a smaller value to LSmall; then, the Luminance Tolerance luminence Tolerance is set as an acceptable Luminance difference, preventing the Luminance difference between the two from being too large. Specifically, the maximum Tolerance value LBig ' of the right-handed actual Luminance can be calculated according to LBig ' (1+ Luminance distance LSmall), and if LBig ' is smaller than LBig, the Luminance difference is too large; wherein the Luminance Tolerance luminence Tolerance may be set as a percentage.
When the brightness difference is too large, namely when the brightness difference does not fall within the brightness tolerance range, the adjustment is performed according to the brightness tolerance, for example, the actual brightness counted by the imaging public visual field of one camera can be adjusted by adjusting the exposure parameter of the other camera, so that the image brightness of the camera approaches to the image brightness of the other camera until the image brightness difference of the two cameras is within the brightness tolerance range. Of course, the two cameras can be adjusted simultaneously, so that the image brightness of the two cameras is close to each other until the brightness difference of the two cameras is within the brightness tolerance range.
The operation has the advantages that when the current brightness value determined according to the exposure parameters corrected by the lookup table cannot reach the expected target brightness due to interference of other factors, the double-shot system determines whether the brightness difference of the two cameras is within the brightness tolerance range, and if so, the next step 6 is executed; if not, forcibly adjusting the exposure parameters of the cameras to correct the image brightness, so that the image brightness difference of the two cameras is within the brightness tolerance range, and finally ensuring the brightness of the fused images to be consistent.
6. Parameter injection and adjustment of the next adjustment period:
after the first image and the second image corresponding to the current left shot and the current right shot are respectively adjusted through the steps, the image fusion can be carried out according to the existing image fusion method, and the final image is output. And then, the left shot and the right shot of the double shot are respectively adjusted in the next adjustment period, and the adjustment process is the same as that of the single shot automatic exposure process, and is not repeated herein.
It should be noted that the terms "first", "second", "third", and "fourth" in the embodiments of the present invention are merely used to distinguish the terms "camera", "image", and "brightness value" that are modified later, and are not limited to the terms.
EXAMPLE III
Fig. 3 is a schematic structural diagram of a calibration apparatus for automatic exposure parameters based on a dual-camera system according to a third embodiment of the present invention, which may be implemented in a hardware and/or software manner, and may be generally configured in a user terminal independently to implement the method of the present embodiment. As shown in fig. 3, the calibration apparatus for automatic exposure parameters based on a dual-camera system specifically includes: an image acquisition module 310, a brightness value statistics module 320, and an exposure parameter recording module 330.
The image obtaining module 310 is configured to obtain a first image and a second image of a target object based on a first camera and a second camera, respectively; a brightness value statistics module 320, configured to obtain a common field of view of the first camera and the second camera, and count a first brightness value and a second brightness value of a pixel region in the common field of view in the first image and the second image, respectively; the exposure parameter recording module 330 is configured to adjust an exposure parameter so that the first luminance value and the second luminance value are the same and reach at least one preset target luminance value respectively, and record the exposure parameter of the first camera and the exposure parameter of the second camera corresponding to the preset target luminance value respectively.
According to the technical scheme of the embodiment of the invention, the public view field of the first camera and the second camera is obtained, the double-shot exposure is cooperatively controlled by utilizing the common statistic of the images of the double-shot system in the public view field, so that the problems of brightness deviation or unmatched brightness caused by the unique view field of the first camera and the second camera are solved, the exposure parameters of the first camera and the second camera reaching the same preset target brightness values are recorded, the brightness response inconsistency of the first camera and the second camera in the double-shot system is compensated by adjusting the exposure parameters, the brightness consistency of the first camera and the second camera in the double-shot system is realized, and the imaging effect is optimized.
On the basis of the above technical solutions, the luminance value statistics module may be configured to:
and determining the common field of view of the first camera and the second camera according to the distance between the first camera and the second camera, the effective shooting distance and the field angle in the current scene.
On the basis of the above technical solutions, the calibration apparatus for automatic exposure parameters based on a dual-camera system may further include: an exposure parameter query module 340, a current image acquisition module 350, and a final image acquisition module 360.
The exposure parameter query module 340 is configured to query and acquire exposure parameters corresponding to the first camera and the second camera according to a current target brightness value of a current public view field; a current image obtaining module 350, configured to obtain, by using the exposure parameter, a third image and a fourth image of the current object based on the first camera and the second camera, respectively; the current common view field is a common view field of the first camera and the second camera in the current scene; a final image obtaining module 360, configured to fuse the third image and the fourth image to obtain a final image.
On the basis of the above technical solutions, the final image acquisition module may be configured to:
counting the current actual brightness value of the third image and the fourth image in the current common field of view;
judging whether the current actual brightness value is within a preset brightness tolerance range;
if so, fusing the third image and the fourth image to obtain a final image;
if not, after the current actual brightness value is corrected to the current target brightness value, the third image and the fourth image are fused to obtain a final image.
On the basis of the above technical solutions, the exposure parameters may include an exposure line and a gain.
The embodiment of the invention also provides a terminal which is provided with the calibration device for the automatic exposure parameters based on the double-camera system provided by any embodiment of the invention. Typically, the terminal may include devices such as a mobile phone, a tablet computer, a notebook computer, a smart watch, and a digital camera.
The device and the terminal can execute the methods provided by the first embodiment and the second embodiment of the invention, and have corresponding functional modules and beneficial effects for executing the methods. For details of the technology that are not described in detail in this embodiment, reference may be made to the methods provided in the first embodiment and the second embodiment of the present invention.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (6)
1. A calibration method of automatic exposure parameters based on a dual-camera system is characterized by comprising the following steps:
acquiring a first image and a second image of a target object based on a first camera and a second camera respectively;
acquiring a common view field of the first camera and the second camera, and respectively counting a first brightness value and a second brightness value of a pixel region in the common view field in the first image and the second image;
adjusting exposure parameters to enable the first brightness value and the second brightness value to be the same and respectively reach at least one preset target brightness value, and respectively recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness value;
inquiring and acquiring exposure parameters corresponding to the first camera and the second camera according to the current target brightness value of the current public view field;
acquiring a third image and a fourth image of the current object based on the first camera and the second camera respectively by adopting the exposure parameters; the current common view field is a common view field of the first camera and the second camera in the current scene;
fusing the third image and the fourth image to obtain a final image;
the fusing the third image and the fourth image to obtain a final image includes:
counting the current actual brightness value of the third image and the fourth image in the current common field of view;
judging whether the current actual brightness value is within a preset brightness tolerance range;
if so, fusing the third image and the fourth image to obtain a final image;
if not, after the current actual brightness value is corrected to the current target brightness value by adjusting exposure parameters, the third image and the fourth image are fused to obtain a final image.
2. The method of claim 1, wherein the acquiring a common field of view for the first and second cameras comprises:
and determining the common field of view of the first camera and the second camera according to the distance between the first camera and the second camera, the effective shooting distance and the field angle in the current scene.
3. The method of claim 1 or 2, wherein the exposure parameters comprise an exposure line and a gain.
4. The utility model provides a calibration arrangement of automatic exposure parameter based on two camera systems which characterized in that includes:
the image acquisition module is used for acquiring a first image and a second image of the target object based on the first camera and the second camera respectively;
the brightness value counting module is used for acquiring a common view field of the first camera and the second camera and respectively counting a first brightness value and a second brightness value of a pixel area positioned in the common view field in the first image and the second image;
the exposure parameter recording module is used for adjusting exposure parameters so that the first brightness value and the second brightness value are the same and reach at least one preset target brightness value respectively, and recording the exposure parameters of the first camera and the second camera corresponding to the preset target brightness values respectively;
the exposure parameter query module is used for querying and acquiring the exposure parameters corresponding to the first camera and the second camera according to the current target brightness value of the current public view field;
the current image acquisition module is used for acquiring a third image and a fourth image of a current object based on the first camera and the second camera respectively by adopting the exposure parameters; the current common view field is a common view field of the first camera and the second camera in the current scene;
a final image obtaining module, configured to fuse the third image and the fourth image to obtain a final image;
the final image acquisition module is specifically configured to:
counting the current actual brightness value of the third image and the fourth image in the current common field of view;
judging whether the current actual brightness value is within a preset brightness tolerance range;
if so, fusing the third image and the fourth image to obtain a final image;
if not, after the current actual brightness value is corrected to the current target brightness value by adjusting exposure parameters, the third image and the fourth image are fused to obtain a final image.
5. The apparatus of claim 4, wherein the brightness value statistics module is configured to:
and determining the common field of view of the first camera and the second camera according to the distance between the first camera and the second camera, the effective shooting distance and the field angle in the current scene.
6. The apparatus of claim 4 or 5, wherein the exposure parameters comprise an exposure line and a gain.
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| CN108063932B (en) * | 2017-11-10 | 2020-10-27 | 广州极飞科技有限公司 | Luminosity calibration method and device |
| CN109417604A (en) * | 2017-11-30 | 2019-03-01 | 深圳市大疆创新科技有限公司 | Variation calibration method, binocular vision system and computer readable storage medium |
| CN107872625B (en) * | 2017-12-25 | 2020-05-22 | 信利光电股份有限公司 | Dual-camera exposure synchronous control method and system |
| US10757320B2 (en) * | 2017-12-28 | 2020-08-25 | Waymo Llc | Multiple operating modes to expand dynamic range |
| CN107948542A (en) * | 2018-01-15 | 2018-04-20 | 上海兴芯微电子科技有限公司 | Multi-cam exposure control method and device |
| CN108650442A (en) * | 2018-05-16 | 2018-10-12 | Oppo广东移动通信有限公司 | Image processing method and device, storage medium, electronic equipment |
| CN108848294B (en) * | 2018-08-15 | 2020-09-04 | 努比亚技术有限公司 | Shooting parameter adjusting method, terminal and computer readable storage medium |
| CN109151336B (en) * | 2018-10-15 | 2020-11-13 | 长沙智能驾驶研究院有限公司 | Camera synchronization method, device and system, storage medium and computer equipment |
| WO2020252739A1 (en) * | 2019-06-20 | 2020-12-24 | 深圳市大疆创新科技有限公司 | Method and apparatus for acquiring gain coefficient |
| CN113129241B (en) * | 2019-12-31 | 2023-02-07 | RealMe重庆移动通信有限公司 | Image processing method and device, computer readable medium and electronic equipment |
| CN112640421A (en) * | 2020-03-18 | 2021-04-09 | 深圳市大疆创新科技有限公司 | Exposure method, exposure device, shooting equipment, movable platform and storage medium |
| WO2021223245A1 (en) * | 2020-05-08 | 2021-11-11 | Guangdong Oppo Mobile Telecommunications Corp., Ltd. | Method and apparatus for controlling exposure level, and computer usable medium storing software for implementing method |
| CN111614865B (en) * | 2020-05-13 | 2023-06-09 | 展讯通信（上海）有限公司 | Multi-shot brightness synchronization method, equipment, device and storage medium |
| CN115550556B (en) * | 2021-06-25 | 2023-10-24 | 荣耀终端有限公司 | Exposure intensity adjusting method and related device |
| CN114125314A (en) * | 2021-11-23 | 2022-03-01 | 展讯通信（上海）有限公司 | Brightness synchronization method, device, storage medium and equipment |
| CN116708954A (en) * | 2022-12-30 | 2023-09-05 | 荣耀终端有限公司 | Photographing method and electronic equipment |
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| CN104618691A (en) * | 2015-01-29 | 2015-05-13 | 桂林长海发展有限责任公司 | Panoramic brightness balance regulating system and regulating method |
| CN105894482B (en) * | 2015-11-06 | 2019-05-03 | 法法汽车(中国)有限公司 | Balance the method and system of luminance difference between each visual point image |
| CN109660738B (en) * | 2015-12-22 | 2021-01-12 | 北京奇虎科技有限公司 | Exposure control method and system based on double cameras |
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