CN113947534A

CN113947534A - Image correction method and device

Info

Publication number: CN113947534A
Application number: CN202010690402.4A
Authority: CN
Inventors: 李佳桦
Original assignee: Coretronic Corp
Current assignee: Coretronic Corp
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2022-01-18
Also published as: TW202205201A; TWI754334B

Abstract

The invention provides an image correction method and device. The method comprises the following steps: obtaining a plurality of reference images related to a specific object; estimating the area average brightness of the central area of each reference image to generate a target image; obtaining a specific reference image in the reference images, wherein the specific reference image comprises a specific image area, and the specific image area is divided into a plurality of image blocks; estimating the block average brightness of each image block to generate an initial image; a corrected image is generated based on the target image and the initial image. The image correction method and device of the invention provide an image correction mechanism capable of avoiding lens shadow and uneven illumination.

Description

Image correction method and device

[ technical field ] A method for producing a semiconductor device

The present invention relates to image processing technologies, and more particularly, to an image correction method and apparatus.

[ background of the invention ]

Generally, digital camera imaging often encounters Lens shading (Lens shading) and Non-uniform illumination (Non-uniform illumination). The lens shading is also called Vignetting (Vignetting), which means that the light flux of the lens decreases from the center to the periphery due to the optical characteristics of the lens, so that the image shows a phenomenon that the central area is bright and the image gradually darkens toward the periphery, as shown in fig. 1A. The non-uniform illumination is the phenomenon of non-uniform image brightness caused by poor illumination of the object, interference of ambient light, or non-uniform self-illumination of the object, as shown in fig. 1B.

In general photography, the above phenomena can be reduced by moving the position, adjusting the aperture and focal length of the camera, or even selecting the lens to be replaced, but if the image splicing or the automatic optical detection of the fixed camera position is desired, some lens shadows or uneven illumination phenomena may indirectly affect the subsequent application of the image.

Therefore, it is an important issue for those skilled in the art to design an image correction mechanism capable of avoiding lens shading and uneven illumination.

[ summary of the invention ]

Accordingly, the present invention is directed to an image correction method and apparatus, which can solve the above problems.

The invention provides an image correction method, which comprises the following steps: obtaining a plurality of reference images related to a specific object, wherein the specific object is divided into a plurality of object blocks, and the central area of each reference image corresponds to the object block; estimating a region average brightness of the central region of each reference image, and generating a target image according to the region average brightness of the central region of each reference image; obtaining a specific reference image in the reference images, wherein the specific reference image comprises a specific image area, and the specific image area is divided into a plurality of image blocks; estimating a block average brightness of each image block, and generating an initial image according to the block average brightness of each image block; a corrected image is generated based on the target image and the initial image.

The invention provides an image correction device, which comprises an image capturing device, a storage circuit and a processor. The image capturing device is used for acquiring a plurality of reference images related to a specific object. The memory circuit stores a plurality of modules. The processor is coupled to the storage circuit and the image capturing device, accesses the module, and receives the reference image from the image capturing device, wherein the specific object is divided into a plurality of object blocks, the central area of each reference image corresponds to the object block, the average brightness of a region of the central area of each reference image is estimated, a target image is generated according to the average brightness of the region of the central area of each reference image, a specific reference image in the reference images is obtained, the specific reference image comprises a specific image region, the specific image region is divided into a plurality of image blocks, the average brightness of a region of each image block is estimated, an initial image is generated according to the average brightness of the region of each image block, and a correction image is generated based on the target image and the initial image.

Based on the above, the corrected image generated by the image correction method and apparatus of the present invention can be used to perform image correction on the to-be-corrected image in which the other shooting environments, the shooting parameters, and the shooting distances are all the same, so as to improve the problems of lens shading and uneven illumination existing in the to-be-corrected image.

[ description of the drawings ]

Fig. 1A is an image with a lens shading problem.

FIG. 1B is an image known to have non-uniform illumination problems.

Fig. 2 is a schematic diagram illustrating an image correction apparatus according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating an image correction method according to an embodiment of the invention.

FIG. 4 is a schematic diagram illustrating an embodiment of obtaining a reference image of a specific object.

FIG. 5A is a schematic diagram illustrating obtaining a reference image according to an embodiment of the invention.

FIG. 5B is a schematic diagram of generating a target image according to the diagram of FIG. 5A.

FIG. 6A is a specific image area divided into a plurality of image blocks according to the illustration in FIG. 5B.

FIG. 6B is a schematic diagram of generating an initial image according to the diagram of FIG. 6A.

FIG. 7 is a schematic diagram of generating a corrected image according to the diagrams of FIG. 5B and FIG. 6B.

FIG. 8 is a schematic diagram of image correction according to the diagram of FIG. 7.

[ notation ] to show

200 image correction device

202 memory circuit

204 processor

206 image taking device

400 specific object

401,413 object blocks

499 movable platform

501,513 reference image

501a,513a central region

513b specific image area

First region luminance distribution map 530

531,543 first luminance Block

601,613 image block

630 second region luminance distribution map

631,643 second luminance Block

M1 target image

M2 initial image

M3 corrected image

S310-S350 step

TM image to be corrected

TM' brightness correction image.

[ detailed description ] embodiments

The foregoing and other technical and scientific aspects, features and utilities of the present invention will be apparent from the following detailed description of a preferred embodiment, taken in conjunction with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology is used for purposes of illustration and is in no way limiting.

Fig. 2 is a schematic view of an image correction apparatus according to an embodiment of the present invention. As shown in fig. 2, the image calibration apparatus 200 includes a memory circuit 202, a processor 204 and an image capturing device 206. In various embodiments, the Memory circuit 202 is, for example, any type of fixed or removable Random Access Memory (RAM), Read-Only Memory (ROM), Flash Memory (Flash Memory), hard disk, or the like, or a combination thereof, and can be used to record a plurality of program codes or modules.

The processor 204 is coupled to the memory Circuit 202 and may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor, a plurality of microprocessors (microprocessors), one or more microprocessors in conjunction with a digital signal processor core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), any other type of Integrated Circuit, a state Machine, an Advanced RISC Machine (ARM) based processor, and the like.

The image capturing device 206 is coupled to the processor 204, and may be any image capturing device having a Charge Coupled Device (CCD) lens, a Complementary Metal Oxide Semiconductor (CMOS) lens, but is not limited thereto.

In an embodiment of the present invention, the processor 204 can access the modules and program codes recorded in the memory circuit 202 to implement the image correction method of the present invention, which is described in detail below.

Fig. 3 is a flowchart illustrating an image correction method according to an embodiment of the invention. The method of the present embodiment can be executed by the image correction apparatus 200 of fig. 2, and details of steps in fig. 3 will be described below with reference to components shown in fig. 2.

First, in step S310, the processor 204 may obtain a plurality of reference images associated with a specific object, wherein the specific object is divided into a plurality of object blocks, and a central area of each reference image corresponds to each object block. In various embodiments, the designer may select different objects as the specific object according to the requirement, and for convenience of describing the concept of the present invention, it is assumed that the specific object is a display panel provided with a backlight module, but the present invention is not limited thereto. In this case, the specific object is an object that emits self-light, which may cause the problems of lens shading and uneven brightness during image capturing.

Please refer to fig. 4, which is a diagram illustrating a method for obtaining a reference image of a specific object according to an embodiment of the present invention. In fig. 4, the image capturing device 206 is, for example, a camera, which can be used to capture a specific object 400 (e.g., a display panel) to obtain a plurality of reference images. In one embodiment, the image capturing device 206 is used for capturing reference images of the specific object 400, and thus the capturing environment, the capturing parameters, and the capturing distance are fixed.

In one embodiment, the specific object 400 may be placed on a movable platform 499, and this movable platform 499 may be controlled to move the position of the specific object 400. As shown in fig. 4, the specific object 400 can be classified into n x m (e.g., 5x 5) object blocks corresponding to the reference images one-to-one, and each of the reference images is captured with one of the object blocks as a center, for example.

Specifically, taking the object block 401 as an example, when the image capturing device 206 is used for obtaining a reference image corresponding to the object block 401, the movable platform 499 may move the specific object 400 such that the object block 401 is moved to a central area within the image capturing range of the image capturing device 206 (the size of the central area may be matched to the size of the object block 401). Then, the image capturing device 206 captures the specific object 400 to obtain a reference image corresponding to the object block 401. In other words, in the reference image corresponding to the object block 401, the central area corresponds to the object block 401.

Taking the object block 413 as an example, when the image capturing device 206 is used for obtaining a reference image corresponding to the object block 413, the movable platform 499 may move the specific object 400 such that the object block 413 is moved to a central area within an image capturing range of the image capturing device 206 (the size of the central area may be matched to the size of the object block 413). Then, the image capturing device 206 captures the specific object 400 to obtain a reference image corresponding to the object block 413. In other words, in the reference image corresponding to the object region 413, the central area corresponds to the object region 413.

Based on the above teachings, the image capturing device 206 can obtain the reference image corresponding to each object block. Taking fig. 4 as an example, the image capturing device 206 can obtain 25 reference images corresponding to the 5 × 5 object blocks respectively. In other embodiments, the designer can select the desired n and m values as required to divide the specific object 410 into the desired number of object blocks. In one embodiment, n and m may be both odd numbers, so that a central object block (e.g., object block 413) may exist in the obtained specific block.

In other embodiments, the processor 204 may also obtain a reference image of the specific object 400 captured by other image capturing devices, but is not limited thereto. In addition, in some embodiments, after the reference images are obtained, the processor 204 may further eliminate temporal noise in each reference image to improve the subsequent image processing result.

For the understanding of the concept of the present invention, the following description is made with reference to FIG. 5A. Fig. 5A is a schematic diagram illustrating a reference image acquisition according to an embodiment of the invention. In fig. 5A, it is assumed that 5 × 5 reference images are obtained by capturing the specific object 400 by the image capturing device 206 in fig. 3. In other words, the central areas of the 25 reference images shown in fig. 5A correspond to the 25 object blocks in fig. 4 one-to-one.

Taking the reference image 501 as an example, the image capturing device 206 takes the object block 401 as the central area 501 a. Also, as shown in fig. 5A, the relative position of the reference image 501 in all the reference images is the same as the relative position of the object block 401 in all the object blocks (i.e., both are located at the top left corner). Taking the reference image 513 as an example, the image capturing device 206 takes the object block 413 as the central area 513 a. Also, as shown in fig. 5A, the relative position of the reference image 513 in the whole reference image is the same as the relative position of the object block 413 in the whole object block (i.e., both are located at the center). Accordingly, those skilled in the art should understand the manner of obtaining the remaining reference images, which is not described herein. Further, it should be understood that the rectangular outer frame of the central region in each reference image is illustrated only as a visual aid, and the illustrated rectangular outer frame does not actually exist in the reference image.

Thereafter, in step S320, the processor 204 may estimate the area average brightness of the central area of each reference image, and generate the target image according to the area average brightness of the central area of each reference image. For the understanding of the concept of the present invention, the following description is made with reference to FIG. 5B.

Please refer to fig. 5B, which is a schematic diagram of generating a target image according to fig. 5A. In fig. 5B, the processor 204 may configure the local average luminance of the central region of each reference image into a first local luminance distribution map 530 according to the relative position of each reference image, wherein the first local luminance distribution map 530 may include a plurality of first luminance blocks, and each first luminance block may correspond to the local average luminance of the central region of each reference image.

Taking the reference image 501 of fig. 5B as an example, the processor 204 may estimate the area average luminance (e.g., the luminance average of each pixel in the central area 501 a) of the central area 501a of the reference image 501, and then represent the area average luminance by the first luminance block 531. Taking the reference image 513 of fig. 5B as an example, the processor 204 may estimate a local average luminance (e.g., an average luminance of each pixel in the central region 513 a) of the central region 513a of the reference image 513, and represent the local average luminance by the first luminance block 543. Accordingly, those skilled in the art should understand how to obtain other first local luminance blocks in the first local luminance distribution graph 530, and the details are not repeated herein.

The processor 204 may then perform a first interpolation algorithm on the first region luminance distribution map 530 to generate a target image M1, wherein the size of the target image M1 is the same as the specific region in the reference image 513, which is the remaining region of the image after the black border is removed. In various embodiments, the first interpolation algorithm is, for example, a cubic interpolation algorithm or a linear interpolation algorithm, but may not be limited thereto.

Next, in step S330, the processor 204 may obtain a specific reference image of the reference images, wherein the specific reference image may include a specific image area, and the specific image area may be divided into a plurality of image blocks. In one embodiment, the specific reference image may be assumed to be captured by the image capturing device 206 with the central object block (i.e., the object block 413) as the center. In other words, the specific reference image is the reference image 513 in fig. 5B, but the invention is not limited thereto. In other embodiments, the designer may select other reference images as the specific reference image according to the requirement.

Referring to fig. 6A, a specific image area divided into a plurality of image blocks according to the illustration in fig. 5B is shown. In the present embodiment, the specific image area 513b included in the specific reference image (i.e. the reference image 513) is, for example, a bright area in the specific reference image, i.e. a remaining area after removing a black border in the reference image 513, but the invention is not limited thereto. Thereafter, the specific image area 513b can be divided into axb image blocks according to the requirement of the designer. In fig. 6A, the specific image area 513b can be divided into 5 × 5 image blocks (e.g. the image block 601 located at the top left corner and the image block 613 located at the middle), but the invention is not limited thereto. In some embodiments, a, b may both be odd.

Then, in step S340, the processor 204 may estimate the block average luminance of each image block and generate an initial image according to the block average luminance of each image block.

Please refer to fig. 6B, which is a schematic diagram illustrating an initial image generated according to fig. 6A. In fig. 6B, the processor 204 may configure the block average luminance of each image block into a second local luminance distribution map 630 according to the relative position of each image block in the specific image region 513B, wherein the second local luminance distribution map 630 includes a plurality of second luminance blocks, and each second luminance block corresponds to the block average luminance of each image block.

Taking the image block 601 in fig. 6B as an example, the processor 204 may estimate the block average luminance (e.g., the luminance average of each pixel in the image block 601) of the image block 601, and then represent the block average luminance as the second luminance block 631. Taking the image block 613 of fig. 6B as an example, the processor 204 may estimate a block average luminance (e.g., an average luminance of each pixel in the image block 613) of the image block 613, and represent the block average luminance as the second luminance block 643. Accordingly, those skilled in the art should understand how to obtain other second local luminance blocks in the second local luminance distribution chart 630, and the details are not repeated herein.

Thereafter, the processor 204 may perform a second interpolation algorithm on the second region intensity distribution map 630 to generate an initial image M2, wherein the size of the initial image M2 is the same as the specific region 513b in the reference image 513. In various embodiments, the second interpolation algorithm is, for example, a cubic interpolation algorithm or a linear interpolation algorithm, but may not be limited thereto.

On the other hand, the order of steps S320 and S330 to S340 is not limited in the image correction method, in other words, steps S330 to S340 may be executed first, and then step S320 may be executed.

After obtaining the target image M1 and the initial image M2 according to steps S320 and S340, the processor 204 may generate a corrected image based on the target image M1 and the initial image M2 in step S350.

Fig. 7 is a schematic diagram of generating a corrected image according to fig. 5B and fig. 6B. In the present embodiment, the processor 204 may divide the target image M1 by the initial image M2 to generate a corrected image M3. In one embodiment, the target image M1 and the initial image M2 are each a grayscale image, wherein the target image M1 includes a plurality of first pixels, the initial image M2 includes a plurality of second pixels, and the first pixels correspond to the second pixels one-to-one. In addition, the corrected image M3 may include a plurality of third pixels. In this case, the processor 204 may divide the gray-scale value of each first pixel by the corresponding gray-scale value of each second pixel to generate each third pixel in the corrected image M3, but the invention is not limited thereto.

Therefore, the corrected image M3 obtained by the above teaching can be used for performing image correction operation on other images to be corrected. Please refer to fig. 8, which is a schematic diagram illustrating image correction according to fig. 7. In the present embodiment, it is assumed that the image to be corrected TM is a specific image area of an image captured by an object (e.g., another display panel) similar to the specific object 400, and the related capturing environment and capturing parameters are also the same as the capturing environment and capturing parameters when the image capturing device 206 captures the specific object 400.

As shown in fig. 8, the image TM to be corrected has lens shading and uneven illumination. In this case, the processor 204 may correct the image to be corrected TM into the luminance corrected image TM' based on the corrected image M3. In one embodiment, the processor 204 may multiply the corrected image M3 by the image to be corrected TM to generate a luminance corrected image TM'. For example, the processor 204 may generate the luminance calibration image TM' by point-to-point multiplying the calibration image M3 and the image to be calibrated TM.

As can be seen from fig. 8, the problems of lens shading and uneven illumination in the luminance corrected image TM' are improved to some extent compared to the image TM to be corrected.

In some embodiments, after the processor 204 performs steps S310 to S350 to obtain the corrected image M3, the processor 204 may further obtain a plurality of other reference images associated with another specific object, and generate another corrected image based on the other reference images, wherein the shooting environment of the other specific object is the same as the shooting environment of the specific object 400. In other words, after performing steps S310 to S350 based on the specific object 400 to obtain the corrected image M3, the processor 204 may also perform steps S310 to S350 based on another specific object to obtain another corrected image. Thereafter, the processor 204 may generate an average corrected image based on the corrected image M3 and the other corrected image. Therefore, the obtained average corrected image can be more widely used, thereby being beneficial to further improving the result of image correction. Then, the processor 204 may obtain an image to be corrected (e.g., the image to be corrected TM), and correct the image to be corrected into a corresponding luminance corrected image based on the average corrected image.

In other embodiments, the processor 204 may further modify the average corrected image to obtain a more objective and general average corrected image after performing steps S310 to S350 to obtain the corresponding corrected image based on other specific objects, but the invention is not limited thereto.

In summary, the image correction method and apparatus provided by the present invention can complete the correction of lens shading and uneven illumination without special equipment or illumination conditions, and the operation process is simple and easy to implement, and the operation architecture is easy to implement, so that the method and apparatus are suitable for being used in the situation where the shooting parameters and the shooting environment are fixed and the property of the specific object to be measured is fixed.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the scope of the invention, which is defined by the appended claims and their equivalents, and all changes and modifications that are within the scope of the invention are therefore intended to be covered by the claims. Furthermore, it is not necessary for any embodiment or claim of the invention to achieve all of the objects or advantages or features disclosed herein. In addition, the abstract and the title of the invention are provided for assisting the search of patent documents and are not intended to limit the scope of the invention. In addition, the terms "first", "second", and the like in the description or the claims are only used for naming images (images) or distinguishing different embodiments or ranges, and are not used for limiting the upper limit or the lower limit of the number of components.

Claims

1. An image correction method, comprising:

obtaining a plurality of reference images related to a specific object, wherein the specific object is divided into a plurality of object blocks, and the central area of each reference image corresponds to the plurality of object blocks;

estimating the area average brightness of the central area of each reference image, and generating a target image according to the area average brightness of the central area of each reference image;

obtaining a specific reference image in the plurality of reference images, wherein the specific reference image comprises a specific image area, and the specific image area is divided into a plurality of image blocks;

estimating the block average brightness of each image block, and generating an initial image according to the block average brightness of each image block;

and generating a corrected image based on the target image and the initial image.

2. The method according to claim 1, wherein the object blocks include a first object block, the reference images include a first reference image corresponding to the first object block, the first reference image is captured by an image capturing device with the first object block as a center, and the capturing environment, the capturing parameters and the capturing distance of the image capturing device capturing each of the reference images are the same.

3. The method according to claim 1, wherein the object blocks include a central object block, and the specific reference image is captured by an image capturing device with the central object block as a center.

4. The method of claim 1, wherein the specific image area is a bright area in the specific reference image.

5. The method of claim 1, wherein the step of generating the target image according to the area average brightness of the central area of each of the reference images comprises:

configuring the area average brightness of the central area of each reference image into a first area brightness distribution map according to the relative position of each reference image, wherein the first area brightness distribution map comprises a plurality of first brightness blocks, and each first brightness block corresponds to the area average brightness of the central area of each reference image;

performing a first interpolation algorithm on the first regional brightness distribution map to generate the target image, wherein the size of the target image is the same as the specific image region of the specific reference image.

6. The method of claim 1, wherein the step of generating the initial image according to the block average luminance of each of the image blocks comprises:

configuring the block average brightness of each image block into a second local brightness distribution map according to the relative position of each image block, wherein the second local brightness distribution map comprises a plurality of second brightness blocks, and each second brightness block corresponds to the block average brightness of each image block;

performing a second interpolation algorithm on the second regional brightness distribution map to generate the initial image, wherein the size of the initial image is the same as the specific image region of the specific reference image.

7. The method of claim 1, wherein the step of generating the corrected image based on the target image and the initial image comprises:

dividing the target image by the initial image to generate the corrected image.

8. The method of claim 7, wherein the target image and the initial image are each grayscale images, the target image includes a plurality of first pixels, the initial image includes a plurality of second pixels, the plurality of first pixels correspond one-to-one to the plurality of second pixels, the corrected image includes a plurality of third pixels, and the step of dividing the target image by the initial image to generate the corrected image includes:

dividing the gray-scale value of each first pixel by the corresponding gray-scale value of each second pixel to generate a plurality of third pixels of the corrected image.

9. The method of claim 1, further comprising:

and acquiring an image to be corrected, and correcting the image to be corrected into a brightness correction image based on the correction image, wherein the shooting environment of the image to be corrected is the same as that of the specific object.

10. The method of claim 9, wherein the step of correcting the image to be corrected into the brightness corrected image based on the corrected image comprises:

and multiplying the corrected image by the image to be corrected to generate the brightness corrected image.

11. The method of claim 1, wherein after the obtaining of the plurality of reference images, the method further comprises excluding temporal noise in each of the reference images.

12. The method of claim 1, further comprising:

obtaining a plurality of other reference images related to another specific object, and generating another corrected image based on the other reference images, wherein the shooting environment of the other specific object is the same as that of the specific object;

generating an average corrected image based on the corrected image and the another corrected image;

and acquiring an image to be corrected, and correcting the image to be corrected into a brightness correction image based on the average correction image.

13. An image calibration device, comprising an image capturing device, a storage circuit and a processor, wherein,

the image capturing device is used for acquiring a plurality of reference images related to a specific object;

the memory circuit stores a plurality of modules; and

the processor is coupled to the memory circuit and the image capturing device, and is configured to access the modules, receive the reference images from the image capturing device, divide the specific object into a plurality of object blocks, each of the center areas of the reference images corresponds to one of the object blocks, estimate an area average brightness of the center area of each of the reference images, generate a target image according to the area average brightness of the center area of each of the reference images, and obtain a specific reference image of the reference images, wherein the specific reference image includes a specific image area, the specific image area is divided into a plurality of image blocks, estimate a block average brightness of each of the image blocks, and generate an initial image according to the block average brightness of each of the image blocks, and generating a corrected image based on the target image and the initial image.

14. The apparatus of claim 13, wherein the object blocks include a first object block, the reference images include a first reference image corresponding to the first object block, the first reference image is captured by an image capturing device with the first object block as a center, and the capturing environment, the capturing parameters, and the capturing distance of the image capturing device capturing each of the reference images are the same.

15. The image rectification device of claim 13, wherein the object blocks include a central object block, and the specific reference image is captured by the image capturing device with the central object block as a center.

16. The image correction device of claim 13, wherein the specific image area is a bright area in the specific reference image.

17. The image correction device of claim 13, wherein the processor is configured to:

18. The image correction device of claim 13, wherein the processor is configured to:

19. The image correction device of claim 13, wherein the processor is configured to:

dividing the target image by the initial image to generate the corrected image.

20. The image correction device of claim 19, wherein the target image and the initial image are each a grayscale image, the target image includes a plurality of first pixels, the initial image includes a plurality of second pixels, the plurality of first pixels correspond one-to-one to the plurality of second pixels, the corrected image includes a plurality of third pixels, and the processor is configured to:

dividing the gray-scale value of each first pixel by the corresponding gray-scale value of each second pixel to generate the plurality of third pixels of the corrected image.

21. The image correction device of claim 13, wherein the processor is further configured to:

22. The image correction device of claim 21, wherein the processor is configured to:

23. The image correction device of claim 13, wherein after the plurality of reference images are acquired, the processor is further configured to reject temporal noise in each of the reference images.

24. The image correction device of claim 13, wherein the processor is further configured to: