JP6365033B2 - Image processing apparatus and program - Google Patents

Description

  The present invention relates to an image processing apparatus and a program.

  Patent Document 1 includes all or representative plural colors from a pixel group in a boundary peripheral region that includes a boundary between an estimated foreground region and an estimated background region and spans both the estimated foreground region and the estimated background region. A process is disclosed for extracting and determining the color of the extracted result image so as to be as different as possible from any of the plurality of extracted colors.

JP 2013-191054 A

  It is an object of the present invention to make the foreground area easy to see while suppressing the background area from being invisible by the mask when masking the background area of the image to make the foreground area easy to see.

According to the first aspect of the present invention, a separation unit that separates a target image into a foreground region and a background region, a foreground lightness that is the lightness of the foreground region, and a background lightness that is the lightness of the background region are grasped. A masking means for masking the background region and performing masking so that a contrast is generated between the background region after the masking and the foreground region. In the case where the foreground lightness is greater than a predetermined lightness and the background lightness is smaller than a preset background lightness, the means of the mask is compared with a case where the foreground lightness is larger than the set background lightness. If the background brightness is larger than a preset background brightness when the brightness is increased and the foreground brightness is less than a predetermined brightness, the set background brightness Compared to smaller than, an image processing apparatus characterized by reducing the brightness of the mask.
According to a second aspect of the present invention, when the mask means increases the brightness of the mask, the brightness of the mask is set to a brightness at which the background region can be seen through the mask. The image processing apparatus according to claim 1, wherein the brightness of the mask when the brightness is reduced is set to a brightness at which the background region can be seen through the mask.
A third aspect of the present invention is the image processing apparatus according to the first or second aspect, further comprising lightness changing means for changing the lightness of the mask using an adjustment value obtained from a user.
The invention according to claim 4 further includes an adjustment value acquisition unit that acquires the adjustment value input by a user, and a touch panel that displays an image after the background area is masked, and the adjustment The image processing apparatus according to claim 3, wherein the value acquisition unit acquires the adjustment value by detecting a movement amount of a user's finger that slides on the touch panel.
The invention according to claim 5 grasps the separation function for separating the target image into the foreground area and the background area, the foreground brightness that is the brightness of the foreground area, and the background brightness that is the brightness of the background area. The computer realizes a grasp function and a mask function for performing masking on the background area and performing the mask so that a contrast is generated between the background area after the masking and the foreground area. The mask function is greater than the set background brightness when the background brightness is smaller than a preset background brightness when the foreground brightness is greater than a preset brightness. Compared to the case, when the brightness of the mask is increased and the foreground brightness is smaller than a predetermined brightness, the background brightness is set in advance. Is greater than the brightness, compared to smaller than the set background brightness, a program characterized to reduce the brightness of the mask.

According to the first aspect of the present invention, when the background area of the image is masked to make the foreground area easy to see, it is possible to make the foreground area easy to see while suppressing the background area from being invisible.
According to claim 2 of the present invention, the user can visually recognize the background area after increasing the brightness of the mask or decreasing the brightness of the mask.
According to claim 3 of the present invention, the brightness of the mask can be changed to the brightness desired by the user.
According to claim 4 of the present invention, it is possible to improve the operability when the user changes the brightness of the mask.
According to the fifth aspect of the present invention, when masking the background region of the image to make the foreground region easy to see, it is possible to make the foreground region easy to see while suppressing the background region from becoming invisible.

1 is a block diagram illustrating a configuration of an image processing apparatus according to an embodiment of the present invention. (A)-(C) is a mimetic diagram explaining signs that a foreground area is separated from an image in an image processing device. It is the figure which showed the flow of a series of processes from the separation process which isolate | separates a foreground area | region and a background area to a masking process. (A)-(E) are the figures which showed the flow of a series of processes from the separation process which isolate | separates a foreground area | region and a background area to a masking process. It is the figure which showed the brightness table. (A), (B) is the figure which showed the specific example of the process using a brightness table. It is a figure explaining the change process of the brightness of a mask. (A)-(C) is a figure explaining the change process of the brightness of a mask.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram illustrating the configuration of an image processing apparatus 1 according to an embodiment of the invention. FIG. 2 is a schematic diagram for explaining how the foreground region Pf is separated from the image P in the image processing apparatus 1.

  The image processing apparatus 1 illustrated in FIG. 1 includes an image acquisition unit 20, a display unit 30, an operation unit 40, a control unit 50, and a storage unit 60. The image processing apparatus 1 is configured by a so-called tablet terminal.

For example, the image acquisition unit 20 acquires the image P (image data of the image P) illustrated in FIG. Here, the image acquisition unit 20 includes, for example, a connection interface connected to an external device. The image data acquired by the image acquisition unit 20 is output to the storage unit 60 configured by a hard disk device or the like, and is temporarily stored in the storage unit 60.
The display unit 30 includes, for example, a touch panel display, and includes a display surface 31 (see FIG. 2A) that displays an image.

For example, the operation unit 40 is formed integrally with the display surface 31 of the display unit 30 (consisting of a part of a touch panel display), and is operated by touching with a finger, a stylus pen, or the like, so that part of the image P The specification of is accepted. In addition, the operation unit 40 includes the foreground seed Sf included in the foreground region Pf (see FIG. 2B) that the user (operator) wants to separate (extract) from the image P displayed on the display surface 31. The designation of (foreground part) and the designation of the background seed Sb included in the background area Pb which is a part of the image P excluding the foreground area Pf are accepted.
In the present embodiment, the foreground seed Sf and the background seed Sb are both designated by lines as shown in FIG. 2B, but are not limited to those designated by lines, and are designated by points. It may be a thing.

  When the foreground seed Sf is designated (when the foreground area Pf is designated), after the user presses the “Fore” button (not shown) displayed on the display surface 31, the user extracts the foreground area Pf. The inner part of the range to be tried is traced with a finger or a stylus pen, and the traced part becomes the foreground seed Sf. The foreground seed Sf is not limited to one as shown in FIG. 2B, and two or more foreground seeds Sf may be designated.

  When designating the background seed Sb, after the user presses a “Back” button (not shown) displayed on the display surface 31, a part outside the range to be extracted as the foreground region Pf by the user Trace with a stylus pen. Thereby, the traced portion becomes the background seed Sb. The background seed Sb is not limited to one, and two or more may be specified. Note that only the foreground seed Sf may be specified and the background seed Sb may not be specified.

In addition to the “Fore” button and the “Back” button, a “Cut” button (not shown) is displayed on the display surface 31. Foreground seed Sf and background seed Sb are specified, or only foreground seed Sf is specified. After completing the above, the “Cut” button is pressed to execute the foreground region Pf forming process. In the present embodiment, the portion designated as the background region Pb is masked as shown in FIG. Thereby, the foreground area Pf is displayed in a more conspicuous state.
Although not described above, as a method of forming the foreground region Pf by the foreground seed Sf and the background seed Sb, an existing method can be cited, for example, a graph cut algorithm.

Returning to FIG. 1, the controller 50 of the image processing apparatus 1 will be described.
The control unit 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) (all not shown).
The ROM stores a control program executed by the CPU. The CPU reads the control program stored in the ROM and executes the control program using the RAM as a work area. Each function (each process) to be described later is realized by executing the control program by the CPU.

  The program executed by the CPU is stored in a computer-readable recording medium such as a magnetic recording medium (magnetic tape, magnetic disk, etc.), an optical recording medium (optical disk, etc.), a magneto-optical recording medium, or a semiconductor memory. Thus, it can be provided to the image processing apparatus 1. Alternatively, it may be downloaded to the image processing apparatus 1 using a communication means such as the Internet.

3 and 4 are diagrams showing a flow of a series of processes from the separation process for separating the foreground area Pf and the background area Pb to the masking process. In addition, FIG. 3 and FIG. 4 are diagrams showing separation processing and masking processing executed by the control unit 50. FIG. 3 is a flowchart showing the flow of processing, and FIG. 4 is a diagram showing a specific example of processing.
As shown in FIG. 3, in this embodiment, first, image data is input to the image processing apparatus 1 (step 101), and this image data is acquired by the image acquisition unit 20. Here, (A) in FIG. 4 shows an input image (image data), and in this example, an image in which a star is displayed in a double circle.

Next, as shown in FIG. 3 and as described above, the control unit 50 functioning as a separation unit performs the separation process of the foreground region Pf and the background region Pb (step 102). Thereafter, a mask image, which is a mask image, is generated (step 103).
Here, FIG. 4B shows a foreground area Pf and a background area Pb. Further, FIG. 4B illustrates a mask image. Here, the mask image is generated so that its contour matches the contour of the background region Pb.

  Thereafter, as shown in step 104 of FIG. 3, color analysis processing is performed for each of the foreground region Pf and the background region Pb. Specifically, as shown in FIG. 4C, the control unit 50 that also functions as a grasping unit grasps the brightness (brightness distribution) of the entire image for each of the foreground region Pf and the background region Pb.

Next, the color of the mask image generated in step 103 is determined (step 105). Specifically, a process of changing (adjusting) the brightness (density) of the mask image generated in step 103 is performed. As a result, as shown in FIG. 4D, a new mask image with a changed brightness is generated.
Next, as shown in step 106 of FIG. 3, the background region Pb is combined with the new mask image generated in step 105, and the background region Pb (hereinafter, “ May be referred to as “masked background region Pb”). In other words, the control unit 50 functioning as a mask unit masks the background area Pb using the new mask image generated in step 105 to generate a masked background area Pb.

  Next, the masked background region Pb and the foreground region Pf obtained by the separation processing in step 102 are combined to generate a combined image (hereinafter referred to as “masked combined image”). Next, display processing of the masked composite image is performed (step 107). Thereby, in this embodiment, the foreground region Pf selected by the user is displayed in a more conspicuous state.

  Here, in the present embodiment, the characteristics of the human eye, which is superior in color recognition than color recognition, are used. When the brightness of the background area Pb is changed, the user operating the image processing apparatus 1 can recognize the boundary between the foreground area Pf and the background area Pb from the high sensitivity of light and darkness. In the processing of this embodiment, only the brightness changes, and the hue does not change. Therefore, the foreground region Pf becomes conspicuous while suppressing the change in the impression of the entire image.

By the way, in the present embodiment, as described above, the foreground region Pf and the background region Pb are separated, and the background region Pb is covered with a mask.
By the way, if this mask is, for example, black, etc., the background area Pb cannot be seen at all, and it is difficult to determine whether the foreground area Pf and the background area Pb are separated as intended. Become. In other words, the foreground area Pf and the background area Pb may be separated at a place different from the intended place due to an operation mistake or the like. In such a case, a black mask is formed and the background area Pb is If it cannot be seen at all, it is difficult to determine whether or not the separation process is appropriate. For this reason, in this embodiment, it is set as the mask which can see the background area | region Pb after masking.

  On the other hand, if the mask is generated in consideration of only the background area Pb, the brightness of the foreground area Pf and the brightness of the background area Pb are now close, and the foreground area Pf becomes conspicuous. Can be difficult. For this reason, in the present embodiment, the brightness of the mask is determined in consideration of the foreground region Pf and the background region Pb.

Specifically, in this embodiment, a lightness table is stored in the storage unit 60 in order to determine the lightness of the mask, and the lightness of the mask is determined with reference to this lightness table. In addition, in the present embodiment, the brightness of the mask (mask image) is determined in step 105 described above. At this time, the brightness of the mask is determined with reference to this brightness table.
It should be noted that determining the brightness of the mask with reference to the brightness table is merely an example, and a formula for determining the brightness of the mask may be prepared in advance, and the brightness may be determined using this formula.

FIG. 5 is a diagram showing a brightness table.
In this lightness table, the lightness of the foreground region Pf (average lightness of the entire region) (foreground lightness) is classified into two (“low (lightness“ small ”)” and “high (lightness“ large ”)). In addition, the average brightness of the background area Pb (average brightness of the entire area) (background brightness) is also classified into two (“low (lightness“ small ”)” and “high (lightness“ high ”)). Yes. In addition, in the present embodiment, a lightness threshold value that is a lightness threshold value is set in advance, and each of the lightness value of the foreground area Pf and the background lightness value Pb is set to be either a small lightness value or a large lightness value. It is classified into crab.

In this embodiment, a case where one brightness threshold value is set will be described as an example. However, for example, two brightness threshold values may be provided. In this case, for example, the brightness value is smaller than the smaller brightness threshold value. Is small, it is determined that the lightness is small, and when the lightness is larger than the larger lightness threshold, it is determined that the lightness is large.
In the present embodiment, a common brightness threshold is used for determining the brightness of the foreground area Pf (determining whether the brightness is high) and determining the brightness of the background area Pb (deciding whether the brightness is high or low). The lightness threshold value used for the lightness determination may be different from the lightness threshold value used for the lightness determination of the background region Pb.

Here, in the case of the condition (A) in the figure, that is, when the lightness of the foreground region Pf is low (small and dark) and the lightness of the background region Pb is low (small and dark), the generated mask is white. Increase the brightness of the mask (larger and brighter), such as using a similar color.
As a result, the contrast between the foreground area Pf and the background area Pb after masking increases, and the foreground area Pf becomes conspicuous. Further, the mask has a color close to white, and the background area Pb is transparent, so that the background area Pb can be seen.

  In addition, in the case of the condition (A), if the lightness of the mask is reduced, the lightness of the background region Pb is also small, so that the background region Pb may not be visible. For this reason, the brightness of the mask is increased under the condition (A). In addition, the brightness of the mask is increased in order to make the foreground region Pf having a low brightness stand out.

  More specifically, when the lightness of the foreground region Pf is smaller than the lightness threshold value as in the condition (A), the contrast becomes larger and the foreground region Pf becomes more conspicuous as the lightness of the mask is increased. Under the condition (A), the brightness of the background area Pb is smaller than the brightness threshold and the background area Pb is dark. Therefore, if the brightness of the mask is reduced, the background area Pb becomes invisible. For this reason, when the brightness of the foreground area Pf is smaller than the brightness threshold and the brightness of the background area Pb is also smaller than the brightness threshold as in the condition (A), the brightness of the mask is increased.

Next, the condition (B) will be described.
In the case of the condition (B), that is, when the lightness of the foreground region Pf is high (large and bright) and the lightness of the background region Pb is low (small and dark), the generated mask is white that is slightly closer to gray. The mask to be generated is set to lightness from the middle to high. As a result, a contrast is created between the foreground region Pf and the background region Pb after masking. Moreover, since the brightness of the mask is relatively high, the background region Pb becomes transparent and the background region Pb becomes visible.

  In addition, even under the condition (B), if the lightness of the mask is decreased, the lightness of the background region Pb is also small, so that the background region Pb may not be visible. For this reason, the brightness of the mask is increased. On the other hand, under the condition (B), since the brightness of the foreground region Pf is large, if the brightness of the mask is increased, the foreground region Pf becomes less noticeable. For this reason, in this example, the lightness of the mask is set in the middle-high range.

More specifically, when the lightness of the foreground region Pf is larger than the lightness threshold as in the condition (B), the contrast becomes larger and the foreground region Pf becomes more conspicuous as the lightness of the mask is decreased. On the other hand, under the condition (B), the lightness of the background region Pb is smaller than the lightness threshold (an example of the set background lightness) and the background region Pb is dark. Therefore, if the lightness of the mask is reduced, the background region Pb becomes invisible. There is a fear.
For this reason, when the lightness of the foreground area Pf is larger than the lightness threshold while the lightness of the background area Pb is smaller than the lightness threshold as in the condition (B), the lightness of the background area Pb is lightness. The brightness of the mask is increased as compared with the case where it is larger than the threshold (as compared with the case of condition (D) described later). Thereby, the background area Pb located behind can be seen through the mask.

Next, the condition (C) will be described.
In the case of the condition (C), that is, when the lightness of the foreground region Pf is low (small and dark) and the lightness of the background region Pb is high (large and light), the lightness of the generated mask is set to low to medium. To the lightness. As a result, a contrast is created between the foreground region Pf and the background region Pb after masking. In addition, the background area Pb is originally high in brightness, so even if a low to medium brightness mask is used, the background area Pb is transparent and the background area Pb can be seen.

  In addition, in the case of the condition (C), since the brightness of the background area Pb is large, if the brightness of the mask is large, the mask of the background area Pb becomes insufficient, and the background area Pb becomes easy to see. Therefore, under this condition, the brightness of the mask is reduced. On the other hand, if the lightness of the mask is made too small, this time, the contrast between the foreground region Pf and the background region Pb becomes difficult to occur, and the foreground region Pf becomes less noticeable. For this reason, under the condition (C), the mask is set to a “low-medium” lightness that is larger than the lowest lightness.

  More specifically, when the lightness of the foreground region Pf is smaller than the lightness threshold as in the condition (C), the contrast becomes larger and the foreground region Pf becomes more conspicuous as the lightness of the mask is increased. On the other hand, under the condition (C), the lightness of the background region Pb is larger than the lightness threshold (an example of the set background lightness) and the background region Pb is bright. Therefore, if the lightness of the mask is increased, the background region Pb Will be transparent. In this case, the background region Pb becomes conspicuous without being hidden.

  For this reason, in the present embodiment, when the brightness of the foreground area Pf is smaller than the brightness threshold while the brightness of the background area Pb is greater than the brightness threshold as in the condition (C), the background area The lightness of the mask is made smaller than when the lightness of Pb is smaller than the lightness threshold (as compared with the case of the above condition (A)). In this way, the background area Pb is less noticeable while the background area Pb can be visually recognized through the mask.

Next, the condition (D) will be described.
In the case of the condition (D), that is, when the lightness of the foreground region Pf is high (large and bright) and the lightness of the background region Pb is also high (large and bright), the lightness of the generated mask is set to “low”. . As a result, a contrast is created between the foreground region Pf and the background region Pb after masking. In addition, the background area Pb is originally high in brightness, so even if a low brightness mask is used, the background area Pb is transparent and the background area Pb can be seen.

  In addition, even under the condition (D), since the brightness of the background area Pb is large, if the brightness of the mask is increased, the mask of the background area Pb becomes insufficient and the background area Pb becomes easy to see. For this reason, the brightness of the mask is reduced even under this condition. Also, under this condition, the lightness of the foreground region Pf is larger and the lightness of the mask is smaller, so that the foreground region Pf is more conspicuous.

  Furthermore, when the lightness of the foreground region Pf is larger than the lightness threshold as in the condition (D), the contrast becomes larger and the foreground region Pf becomes more conspicuous as the lightness of the mask is decreased. Under the condition (D), the brightness of the background area Pb is larger than the brightness threshold value, and the background area Pb is bright. Therefore, the background area Pb can be seen even if the brightness of the mask is reduced. For this reason, when the lightness of the foreground region Pf is larger than the lightness threshold and the lightness of the background region Pb is larger than the lightness threshold as in the condition (D), the lightness of the mask is decreased.

6A and 6B are diagrams illustrating a specific example of processing using a brightness table.
Here, for example, a case is assumed where the background region Pb of the image shown in (A1) of FIG. In the example, the inner portion of the “star” image and the ring portion surrounding the star are set as the foreground region Pf, and the other portion is set as the background region Pb.

  In the example shown in (A), the brightness is high in both the foreground region Pf and the background region Pb. Therefore, in this case, a mask that satisfies the condition (D) in FIG. 5 and has low brightness is set. As a result, as shown in (A2) of FIG. 6A, a mask close to black is applied to the background region Pb.

  In the example shown in FIG. 6B, the inner portion of the “star” image is set as the foreground region Pf, and the other portion is set as the background region Pb. In the example shown in (B), the lightness of the foreground region Pf is small and the lightness of the background region Pb is large. For this reason, in this case, the condition of the condition (C) in FIG. 5 is satisfied, and a “low-medium” lightness mask is set.

  As a result, as shown in (B2) of FIG. 6B, a gray mask can be applied to the background region Pb. In this case, a contrast is generated between the foreground region Pf and the background region Pb, and the foreground region Pf becomes conspicuous. Further, the background area Pb can be seen through, and it can be confirmed whether or not the foreground area Pf and the background area Pb are separated as intended.

  By the way, even when the brightness of the mask is set by the above-described method, the brightness of the mask is too large or too small depending on the case, and the background area Pb becomes invisible or the background area Pb is visible. May be left untouched. For this reason, in the image processing apparatus 1 of the present embodiment, the brightness of the mask can be changed.

  7 and 8 are diagrams for explaining mask brightness change processing. In addition, FIGS. 7 and 8 are diagrams illustrating mask brightness change processing executed by the control unit 50. FIG. 7 is a flowchart showing the flow of processing, and FIG. 8 is a diagram showing a specific example of processing.

  As shown in FIG. 7, in this embodiment, first, the separation process and the mask process described above are executed (step 201). Thereby, for example, an image as shown in FIG. 8B is generated.

  Next, gesture recognition which is recognition processing of an operation performed by the user is performed (step 202). Here, in this example, as shown in FIG. 8B, recognition processing of a finger that slides on the touch panel (display surface 31) is performed. Specifically, the movement amount of the finger is detected. When the movement amount of the finger is detected, a process for changing the brightness of the mask is performed (step 203).

  More specifically, in the present embodiment, mask brightness change processing is performed based on the amount of movement of the user's finger. In addition, in the present embodiment, when changing the brightness of the mask, first, the control unit 50 functioning as an adjustment value acquisition unit acquires an adjustment value used for changing the brightness from the user. Specifically, the movement amount of the user's finger is acquired as an adjustment value. Next, the control unit 50 functioning as brightness change means performs a process of changing the brightness of the mask using this adjustment value. Then, the image subjected to the mask brightness change process is displayed again (step 204).

  More specifically, in this embodiment, from the state shown in FIG. 8B, for example, when the user moves the finger upward in the figure, a process for increasing the brightness of the mask is performed. When the user moves the finger downward in the figure, a process for reducing the brightness of the mask is performed. Here, FIG. 6C illustrates the case where the user moves his / her finger downward, and when the user's finger moves downward, as shown in FIG. The brightness of Pb decreases.

In this example, the case where the brightness of the mask is changed based on the vertical movement of the finger has been described as an example. However, for example, the brightness of the mask is changed based on the horizontal movement of the finger. Also good.
Further, in this example, the case of acquiring the lightness change amount based on the finger movement amount with respect to the touch panel (display surface 31) has been described as an example. However, for example, a numeric keypad is displayed on the touch panel (display surface 31). For example, the user may directly input a specific numerical value regarding the lightness change amount.
In the above description, the case where the image processing apparatus 1 is configured by a so-called tablet terminal has been described as an example. However, the image processing apparatus 1 is configured by a PC (Personal Computer) including a monitor, a keyboard, a mouse, and the like. Also good.

DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 50 ... Control part, P ... Image, Pf ... Foreground area | region, Pb ... Background area | region

Claims (5)

Separating means for separating the target image into a foreground region and a background region;
Grasping means for grasping the foreground lightness that is the lightness of the foreground region and the background lightness that is the lightness of the background region;
Mask means for performing masking on the background region, and performing masking so that a contrast is generated between the background region after performing the masking and the foreground region;
With
The mask means includes
When the foreground lightness is higher than a predetermined lightness, when the background lightness is smaller than a preset background lightness, the lightness of the mask is made larger than when the background lightness is larger than the set background lightness. And
When the foreground lightness is smaller than a predetermined lightness, the lightness of the mask is smaller when the background lightness is larger than a preset background lightness than when the background lightness is smaller than the preset background lightness. An image processing apparatus. When the mask means increases the brightness of the mask, the brightness of the mask is set to a brightness at which the background region can be seen through the mask,
The image processing apparatus according to claim 1, wherein the brightness of the mask when the mask means reduces the brightness of the mask is set to a brightness at which the background region can be seen through the mask.   The image processing apparatus according to claim 1, further comprising a brightness changing unit that changes the brightness of the mask using an adjustment value obtained from a user. Adjustment value acquisition means for acquiring the adjustment value input by the user;
A touch panel for displaying an image after the background area is masked;
Further comprising
The image processing apparatus according to claim 3, wherein the adjustment value acquisition unit acquires the adjustment value by detecting a movement amount of a user's finger that slides on the touch panel. A separation function for separating the target image into a foreground region and a background region;
A grasping function for grasping the foreground lightness that is the lightness of the foreground region and the background lightness that is the lightness of the background region;
A mask function for masking the background region, and performing the mask so that a contrast occurs between the background region after the masking and the foreground region;
Is a program for causing a computer to realize
The mask function is
When the foreground lightness is higher than a predetermined lightness, when the background lightness is smaller than a preset background lightness, the lightness of the mask is made larger than when the background lightness is larger than the set background lightness. And
When the foreground lightness is smaller than a predetermined lightness, the lightness of the mask is smaller when the background lightness is larger than a preset background lightness than when the background lightness is smaller than the preset background lightness. The program characterized by doing.

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