JP2018011151A - Image processing system and control method thereof, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing system that is able to reduce visual discomfort of a user in a case of performing a process of converting a dynamic range of an input image having an emphasized outline area.SOLUTION: An image processing system 100 according to the present invention comprises: an emphasis processing section 126 that performs an emphasis process for coloring and emphasizing an outline area of an input image 10; an emphasizing-color setting section 124 that sets an emphasizing color used with a color for the emphasis process; and a range converting section 127 that forms a converted image by converting a gradation value of the input image 10 subjected to the emphasis process. The range converting section 127 forms a converted image 30 by converting the gradation value, equal to or smaller than a predetermined gradation value, of the input image 10 to a gradation value range into which the converted image 30 can fall. In a case where the gradation value of the outline area of the input image 10 is larger than the predetermined gradation value, the color emphasis setting section 124 sets an emphasis color for the outline area to a color corresponding to a gradation value equal to or larger than the predetermined gradation value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image processing apparatus capable of performing enhancement processing on a contour region of an input image, a control method thereof, and a display device.

  In recent years, there is image data having a dynamic range wider than the display luminance range (dynamic range) of conventional image data. Such a wide dynamic range of the image data corresponds to a display luminance higher than that of the conventional dynamic range of the image data (High Dynamic Range; HDR). Hereinafter, image data having a wide dynamic range is referred to as HDR image data.

  The upper limit of the displayable luminance of the display device that displays the HDR image data may not correspond to the wide dynamic range of the HDR image data. In such a case, a gradation conversion process for converting the dynamic range of the HDR image data into a luminance range (display dynamic range) that can be displayed on the display device may be performed. For example, Patent Document 1 discloses a conventional technique related to gradation conversion processing. Patent Document 1 discloses a gradation conversion process for reducing gradation of an exposure amount larger than a predetermined exposure amount (luminance) when an image is obtained by imaging a subject with a wide dynamic range.

  Further, in a display device that is connected to an imaging device at the time of shooting to check a live view image, the user may check the focus by performing a process of coloring the outline region of the input image.

JP 2001-008065 A

  However, when the gradation conversion process described in Patent Document 1 is performed after the process of emphasizing the outline area on the input image, the outline area is included in the area where the gradation is degraded by the gradation conversion process. In some cases, the colored portion of the mark was displayed. At this time, since the colored contour region is displayed in the region where the gradation is lowered and the image quality is deteriorated, the user may have a visual discomfort.

  In view of the above-described problems, the present invention provides a user's visual discomfort when executing an emphasis process for coloring an outline region of an input image and a process for converting the gradation of the input image. An object of the present invention is to provide an image processing apparatus capable of suppressing the above-described problem.

  According to a first aspect of the display device of the present invention, there is provided an acquisition unit that acquires an input image having a plurality of pixels, an enhancement unit for performing an enhancement process for coloring and emphasizing an outline region of the input image, and the enhancement A setting means for setting an emphasis color used in the coloring of the processing, and a conversion means for converting the gradation value of the input image subjected to the emphasis process to generate a converted image, the conversion means Converting the gradation value below a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that can be taken by the converted image, generating the converted image, and setting means When the gradation value of the contour area of the input image is larger than the predetermined gradation value, the emphasized color of the contour area is set to a color corresponding to the gradation value equal to or higher than the predetermined gradation value. It is characterized by that.

  The image processing apparatus according to the present invention generates a converted image that appears to be substantially not subjected to the contour emphasis process for a region having a display luminance higher than a predetermined display luminance among the contour regions of the input image. It becomes possible to do.

  Therefore, it is possible to suppress the visual discomfort felt by the user when executing the enhancement process for coloring the outline region of the input image and the process for converting the dynamic range of the input image.

It is the schematic diagram which showed the connection of an image processing apparatus, a camera, and a display part. It is a schematic diagram which shows the apparatus block diagram of an image processing apparatus. It is a schematic diagram which shows the relationship between display brightness | luminance and the gradation value of an input image. It is a schematic diagram which shows the input image which the input process part acquired. It is a schematic diagram which shows the relationship between display brightness | luminance and the gradation value of the conversion image which the range conversion part produced | generated. It is a schematic diagram which shows the conversion image 20 at the time of implementing the conversion process mentioned above with respect to the input image. It is a 1st flowchart which shows the conversion image production | generation flow which a control part performs. It is a schematic diagram which shows the converted image 30 output by performing the conversion image output flow. It is a schematic diagram which shows the conversion image at the time of setting the color corresponding to the display brightness smaller than upper limit brightness | luminance Ra as an emphasis color. It is a 2nd flowchart which shows the emphasis color determination process which a control part performs. In a 2nd Example, it is a schematic diagram which shows the conversion image at the time of performing the above-mentioned highlight color setting process. It is a 3rd flowchart which shows the outline emphasis process which a control part performs. It is a 4th flowchart which shows the outline area | region specific process which a control part performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The technical scope of the present invention is determined by the scope of claims, and is not limited by the examples illustrated below. Further, not all the combinations of features described in the embodiments are essential to the present invention. The contents described in this specification and drawings are illustrative and should not be construed as limiting the present invention. Various modifications (including combinations of the embodiments) are possible based on the spirit of the present invention, and they are not excluded from the scope of the present invention. That is, all configurations in which the embodiments and their modifications are combined are also included in the present invention.

(First embodiment)
The display device in the first embodiment of the present invention will be described below. The image processing apparatus 100 according to the first embodiment of the present invention specifies a contour region of an input image and performs a process of coloring the contour region. Further, the image processing apparatus 100 inputs gradation conversion processing for converting a gradation value larger than the designated gradation value in the input image into a maximum gradation value that can be taken by the converted image after gradation conversion. A transformed image is generated by applying to the image. As a result, the image processing apparatus 100 converts the display luminance range (input dynamic range) of the input image into the specified dynamic range. When the gradation value of the contour region of the input image is larger than the specified gradation value, the image processing apparatus 100 displays the contour region with a color represented by a gradation value greater than or equal to the specified gradation value. Color and emphasize.

  FIG. 1 is a schematic diagram illustrating connections between the image processing apparatus 100, the camera 200, and the display unit 300. The image processing apparatus 100 is connected to the camera 200 and the display unit 300. The camera 200 is an imaging device that can output an image obtained by imaging a subject. For example, it is assumed that the camera 200 outputs the acquired live view image to the image processing apparatus.

  The display unit 300 is a display that can display an image on a screen based on the image output from the image processing apparatus 100. For example, it is assumed that the display unit 300 is a transmissive display having a liquid crystal panel and a backlight. Note that the display unit 300 may be a self-luminous display using organic Electro Luminance (EL).

  The image processing apparatus 100 generates a converted image by emphasizing and coloring the contour region of the input image acquired from the camera 200, and converting the dynamic range of the input image with enhanced contouring into the set display range, The image processing apparatus can output to the display unit 300. The image processing apparatus 100 is included in the control board of the display unit 300, and the display unit 300 and the image processing apparatus 100 can constitute a display device.

  FIG. 2 is a schematic diagram illustrating a device configuration diagram of the image processing apparatus 100. The image processing apparatus 100 includes an input unit 110, a control unit 120, a memory 130, and an output unit 140. The input unit 110 is an input terminal that is connected to the camera 200 and acquires an input image.

  The control unit 120 is a control circuit that performs a process of coloring the contour region of the input image, and further converts the input dynamic range of the input image to generate a converted image. The control unit 120 executes processing of each functional block described later to generate a converted image. For example, it is assumed that the control unit 120 is an arithmetic processing unit such as a central processing unit (CPU) or a multi processing unit (MPU). The control unit 120 reads a program stored in the memory 130 and executable by the arithmetic processing unit and parameters for executing the program, and executes processing of each functional block.

  In addition to the arithmetic processing circuit, the control unit 120 may include hardware such as an electronic circuit that can execute a part or all of the functions of each functional block described later.

  The memory 130 is a storage medium that stores a program that can be executed by the arithmetic processing unit and parameters for executing the program, and that can be read by the arithmetic processing unit. For example, it is assumed that the memory 130 is a non-volatile storage medium such as a hard disk. Note that the memory 130 may be a volatile storage medium such as a semiconductor memory, or may include a nonvolatile storage medium and a volatile storage medium.

  The output unit 140 is an output terminal that outputs the converted image generated by the control unit 120 to an external device connected to the image processing apparatus 100. For example, the output unit 140 is connected to the display unit 300 and outputs the converted image to the display unit 300.

  Each functional block of the control unit 120 will be described. It is assumed that the control unit 120 executes the processing of each functional block by executing a program read from the memory 130. The control unit 120 includes an input processing unit 121, a clip region specifying unit 122, an outline region specifying unit 123, an emphasis color setting unit 124, an emphasis processing unit 126, a display range setting unit 125, a range conversion unit 127, and an output processing unit 128. Prepare.

  The input processing unit 121 performs processing for converting the input image acquired from the input unit 110 into data that can be processed by each functional block of the control unit 120. For example, the input processing unit 121 acquires ancillary data added to the input image acquired by the input unit 110 and outputs the ancillary data to the memory 130. Furthermore, it is assumed that the input processing unit 121 outputs the input image to the clip region specifying unit 122, the contour region specifying unit 123, and the enhancement processing unit 126.

  A relationship between the input image and the display luminance will be described. The input image has a plurality of pixels arranged in a matrix, and a signal value (gradation value) corresponding to brightness is designated for each pixel. For example, it is assumed that the input image 10 is a monochrome image in which a gradation value corresponding to brightness is designated for each pixel.

  For example, it is assumed that the display brightness of the image that is the source of the input image is expressed by “reflectance”. The reflectance is a form of expression of brightness, and the brightness is expressed as a relative value. When displaying the brightness using the reflectance, the brightness of the light receiving object illuminated under ambient light is about 0 to 100% of the reflectance, and the illumination light source or the light emitting object such as the sun having a brightness exceeding the reflectance. In many cases, the brightness is a reflectance of 100% or more. For example, the absolute value of the display luminance can be set by designating the absolute value of the luminance corresponding to the reflectance of 100%.

  For example, it is assumed that the gradation value S1 of the input image corresponding to the reflectance R (%) is expressed by Expression 1.

Here, Ri is the upper limit display luminance that can be taken by the dynamic range of the input image. For example, Ri is assumed to be 800%. γ ₁ is a coefficient that associates the display luminance with the gradation value. Bi is the number of bits of the signal representing the gradation value of the input image. For example, it is assumed that Bi is 1023 (10 bits).

  FIG. 3 is a schematic diagram showing the relationship between the display luminance and the gradation value of the input image. The horizontal axis in FIG. 3 indicates the display luminance in terms of reflectance, and the vertical axis indicates the gradation value of the input image. The gradation value of the input image is shown as an upward convex function with respect to the display luminance.

  FIG. 4 is a schematic diagram showing the input image 10 acquired by the input processing unit 121. The input image 10 includes an area 11 in which an image with a low display luminance is displayed and an area 12 in which an image with a high display luminance is displayed. For example, the display brightness of the object or background displayed in the area 11 is 400% or less, and the display brightness of the object or background displayed in the area 12 is greater than 400%.

  The clip area specifying unit 122 specifies, as a clip area, an area composed of pixels having gradation values corresponding to display luminance higher than the upper limit luminance Ra set by the display range setting unit 125 in the input image 10. Execute. The clip area of the input image 10 is an area in which gradation is reduced by a conversion process of a range conversion unit 127 described later. Since the processing of this functional block is used in the image processing apparatus 100 described in the second and subsequent embodiments, the details will be described later.

  The contour region specifying unit 123 detects the contour of the input image 10 and executes processing for specifying the contour region of the input image 10. As a means for detecting the contour region, a conventional contour detection method such as differentiation processing or filter processing can be used.

  The emphasis color setting unit 124 executes processing for setting an emphasis color used for emphasizing the contour region in accordance with the upper limit luminance Ra acquired from the display range setting unit 125 and a user instruction. For example, it is assumed that the emphasized color setting unit 124 sets a color represented by a gradation value corresponding to display luminance higher than the upper limit luminance Ra as an emphasized color.

  The display range setting unit 125 sets an upper limit luminance Ra that is the maximum luminance that can be taken by the dynamic range of the converted image obtained by converting the input image 10. For example, it is assumed that the display range setting unit 125 sets the upper limit luminance Ra according to a user instruction. The display range setting unit 125 may acquire an upper limit value of luminance that can be displayed by the display unit 300 that outputs the converted image, and may set the upper limit luminance Ra. Since the minimum luminance that can be taken by the dynamic range corresponds to black display, the upper limit luminance Ra is a value indicating the dynamic range of the converted image.

  The enhancement processing unit 126 executes an enhancement process for coloring the contour region specified by the contour region specifying unit 123 in the input image 10 with the enhancement color set by the enhancement color setting unit 124. The enhancement processing unit 126 determines whether or not to perform the enhancement processing in accordance with a user instruction. For example, it is assumed that the user has instructed execution of enhancement processing.

  The range conversion unit 127 converts the display luminance of the input image 10 that has been subjected to the enhancement processing on the contour region by the enhancement processing unit 126 so as to be equal to or lower than the upper limit luminance Ra set by the display range setting unit 125. A process of generating an image is executed. In other words, it can be said that the range conversion unit 127 performs a process of converting the dynamic range of the input image 10 into the dynamic range set by the display range setting unit 125 to generate a converted image.

  Specifically, the range conversion unit 127 converts a gradation value corresponding to display luminance higher than the upper limit luminance Ra in the input image 10 into an upper limit value of gradation values that can be taken by the converted image. Further, the range conversion unit 127 converts a gradation value equal to or lower than the gradation value corresponding to the upper limit luminance Ra into a gradation value range that can be taken by the converted image. Hereinafter, such range conversion processing is referred to as clip processing.

  For example, it is assumed that the range conversion unit 127 converts the gradation value S1 of the input image into the gradation value S2 of the converted image using Equation 2 using the acquired display range Ra.

In Equation 2, Ri, γ ₁ , and Bi are parameters used in Equation 1, respectively. γ ₂ is a coefficient that associates the display luminance and the gradation value in the converted image. For example, γ ₂ is assumed to be 2.6. Bo is the number of bits of the signal representing the gradation value of the converted image. For example, Bо is 1023 (10 bits). Note that the gradation value of the converted image can also be represented by a signal such as 8 bits or 12 bits. When S2 in Expression 2 is a value that cannot be expressed by a 10-bit signal, the range converter 127 sets S2 to 1023.

  FIG. 5 is a schematic diagram showing the relationship between the display luminance and the gradation value S2 of the converted image generated by the range converter 127. In FIG. 5, the horizontal axis indicates the display luminance (%), and the vertical axis indicates the gradation value. The solid line in FIG. 5 shows the relationship between the reflectance and the gradation value S2 when the upper limit luminance Ra is 400%. The dotted line in FIG. 5 shows the gradation value S1 of the input image with respect to the reflectance shown in FIG. 3 for comparison.

  As shown by the solid line in FIG. 5, the display luminance greater than the upper limit luminance Ra (400%) is represented by the maximum gradation value (1023) that can be taken in the converted image. In other words, among the gradation values S1 of the input image, gradation values corresponding to display luminance higher than the upper limit luminance Ra can be obtained by the gradation conversion processing by the range conversion unit 127 as the gradation value S2 of the converted image. It can be said that the maximum tone value is converted. Furthermore, among the gradation values S1 of the input image, the gradation values corresponding to the display luminance equal to or lower than the upper limit luminance Ra are within the range that the gradation value S2 of the converted image can take by the gradation conversion processing by the range conversion unit 127. It can be said that it is expanded and converted.

  FIG. 6 is a schematic diagram illustrating a converted image 20 when the above-described conversion process is performed on the input image 10. In the input image 10, the gradation value of the pixel included in the region 22 of the converted image corresponding to the region 12 whose display luminance is higher than the upper limit luminance Ra (400%) is the maximum gradation value that the converted image 20 can take ( 1023), the image in the region 22 is a white image. In other words, it can be said that the region 12 of the input image 10 loses gradation by the conversion process. On the other hand, in the converted image area 21 corresponding to the area 11 of the input image 10, the display luminance is equal to or lower than the upper limit luminance Ra (400%).

  The output processing unit 128 outputs the converted image generated by the range conversion unit 127 to the output unit 140. The output processing unit 128 can convert the converted image into a data format that can be used by an external device connected to the image processing apparatus 100 and output the data. Further, the output processing unit 128 may output the converted image to the memory 130.

  A converted image generation flow executed by the control unit 120 will be described. FIG. 7 is a flowchart illustrating a converted image generation flow executed by the control unit 120.

  The converted image output flow is started when an input image is input to the input processing unit 121 or in response to a user instruction. In S <b> 1, the input processing unit 121 executes processing for acquiring the input image 10. For example, it is assumed that the input processing unit 121 acquires the input image 10 illustrated in FIG. The process proceeds to S2.

  In S2, the display range setting unit 125 executes a process of setting the upper limit luminance Ra. For example, it is assumed that the display range setting unit 125 sets the upper limit luminance Ra to a reflectance of 400%. The process proceeds to S3.

  In S <b> 3, the contour region specifying unit 123 executes processing for specifying the contour region of the input image 10. Assume that the contour region of the input image 10 is, for example, the contour region of an object displayed on the input image 10. The process proceeds to S4.

  In S4, the highlight color setting unit 124 sets the highlight color based on the upper limit luminance Ra set by the display range setting unit 125. The highlight color setting unit 124 sets the color represented by the gradation value corresponding to the display brightness higher than the upper limit brightness Ra as the highlight color. For example, when the upper limit luminance Ra is 400%, the emphasized color setting unit 124 sets a color represented by a gradation value corresponding to a display luminance of 600% as an emphasized color. From Equation 1, the gradation value corresponding to the display luminance of 600% is 898. The emphasized color setting unit 124 sets the color corresponding to the gradation value 898 as the emphasized color. The process proceeds to S5.

  In step S <b> 5, the enhancement processing unit 126 performs contour enhancement processing for coloring the contour region of the input image 10 with the enhancement color set by the enhancement color setting unit 124. It can be said that the emphasis processing unit 126 converts the color of the contour region of the input image 10 into the emphasis color set by the emphasis color setting unit 124. For example, when the color corresponding to the gradation value 898 is set as the enhancement color, the enhancement processing unit 126 converts the gradation value of the outline region of the input image 10 into 898. The process proceeds to S6.

  In S <b> 6, the range conversion unit 127 performs a process of converting the dynamic range of the input image 10 that has been subjected to the contour enhancement process into a dynamic range that is equal to or less than the upper limit luminance Ra set by the display range setting unit 125, thereby Is generated. For example, it is assumed that the range conversion unit 127 generates a converted image using the conversion formula shown in Formula 2. The process proceeds to S7.

  In S <b> 7, the output processing unit 128 converts the converted image into image data in a format that can be used by an external device connected to the image processing apparatus 100, and executes a process of outputting the image data. Thus, the converted image output flow is completed.

  FIG. 8 is a schematic diagram showing the converted image 30 output by executing the above-described converted image output flow. Since the highlight color setting unit 124 sets the color represented by the gradation value corresponding to the display brightness higher than the upper limit brightness Ra as the highlight color, the contour region subjected to the highlight process is subjected to the range conversion process. The converted image is converted into an upper limit value of gradation values that can be taken. That is, in the converted image, the region corresponding to the contour region of the input image 10 is displayed saturated.

  For example, in the region 32 of the converted image 30 corresponding to the region 12 whose display luminance is higher than the upper limit luminance Ra in the input image 10, the contour region included in the region 12 corresponds to the upper limit luminance Ra like the other regions of the region 12. The display brightness is displayed. Therefore, the user does not visually recognize the contour area included in the area 12 of the input image 10. On the other hand, the contour region included in the region 11 composed of pixels having gradation values corresponding to the display luminance equal to or lower than the upper limit luminance Ra in the input image 10 is equal to or lower than the upper limit luminance Ra in the region 31 of the converted image 30 corresponding to the region 11. The display brightness is displayed.

  As a comparative example, a case will be described in which a color composed of gradation values corresponding to display luminance lower than the upper limit luminance Ra is set as an emphasized color. FIG. 9 is a schematic diagram showing a converted image 40 when a color represented by a gradation value corresponding to a display luminance lower than the upper limit luminance Ra is set as an emphasized color.

  The contour region colored in the emphasized color corresponding to the display luminance lower than the upper limit luminance Ra by the enhancement processing unit 126 is converted into a gradation value corresponding to the display luminance lower than the upper limit luminance Ra by the conversion processing by the range conversion unit 127. The Therefore, the gradation value of the converted image region corresponding to the contour region of the input image 10 is a gradation value corresponding to display luminance lower than the upper limit luminance Ra.

  In the area 42 of the converted image 40 illustrated in FIG. 9, the object and background displayed in the area 12 of the input image 10 are displayed with display luminance corresponding to the upper limit luminance Ra. Therefore, the user cannot visually recognize the object and the background displayed in the area 12 of the input image 10. However, since the gradation value of the contour region of the region 42 is converted into a gradation value corresponding to display luminance lower than the upper limit luminance Ra, only the contour region is visually recognized by the user. Therefore, only the contour area is displayed in the area 42 where the object and the background are saturated and displayed with the upper limit luminance Ra, which causes a visual discomfort to the user.

  According to the image processing apparatus described in the first embodiment, the emphasis color is determined so that the contour emphasizing process is not substantially performed on the contour region in which the display luminance is higher than the upper limit luminance Ra in the input image. It becomes possible to do. Therefore, it is possible to suppress the visual discomfort felt by the user.

(Second embodiment)
The image processing apparatus 100 according to the second embodiment identifies a clip area whose gradation value is larger than the specified gradation value from among a plurality of pixels of the input image, and applies to the contour area included in the clip area. The color corresponding to the gradation value greater than or equal to the designated gradation value is set as the highlight color. Furthermore, the image processing apparatus 100 sets the emphasized color set by the user for the contour region included in the region that is not the clip region in the input image.

  Since the apparatus configuration diagram of the image processing apparatus 100 in the second embodiment is the same as that of the first embodiment, description thereof is omitted. In the second embodiment, the converted image output flow executed by the control unit 120 is the same as that in the first embodiment except for the highlight color determination process (S4), and thus the description thereof is omitted. For example, it is assumed that the image processing apparatus 100 executes a contour enhancement process and a range conversion process on the input image 10 illustrated in FIG. 4 to generate and output a converted image.

  A detailed process of the highlight color determination process will be described. FIG. 10 is a flowchart showing an emphasis color determination process executed by the control unit 120. When the emphasized color determination process is started, in S41, the clip area specifying unit 122 has a gradation value corresponding to a display luminance higher than the upper limit luminance Ra set by the display range setting unit 125 in the input image. The process which specifies the area | region which consists of as a clip area is performed. The process proceeds to S42.

  In the process from S <b> 42, the highlight color setting unit 124 executes a process for setting the highlight color for each of the plurality of regions of the input image 10. It is assumed that the plurality of regions of the input image 10 for setting the emphasis color are, for example, each pixel of the input image 10. It should be noted that the area of the input image 10 for setting the emphasis color may be an area composed of a plurality of pixels obtained by dividing the input image 10.

  In step S42, the highlight color setting unit 124 determines whether the target area for setting the highlight color is a clip area. If the target area is a clip area, the process proceeds to S43. If the target area is not a clip area, the process proceeds to S44.

  In S43, the highlight color setting unit 124 sets the color (clip color) represented by the gradation value corresponding to the display brightness equal to or higher than the upper limit brightness Ra as the highlight color of the target area. For example, when the upper limit luminance Ra is set to a reflectance of 800% as in the first embodiment, the emphasis color setting unit 124 emphasizes the color represented by the gradation value corresponding to the reflectance of 600% in the target region. Suppose you want to set the color. The process proceeds to S45.

  In S44, the highlight color setting unit 124 sets the specific color set by the user as the highlight color of the target area. The specific color is a color used for contour emphasis display that can be arbitrarily set by the user, and is input by the user via the input unit 110, for example. For example, it is assumed that the specific color is a color represented by a gradation value corresponding to display luminance lower than the upper limit luminance Ra. The specific color is assumed to be a color represented by a gradation value corresponding to a reflectance of 300%.

  In step S <b> 45, the highlight color setting unit 124 determines whether the highlight color setting process has been completed for all regions of the input image 10. If the highlight color setting process has not been completed for all the areas of the input image 10, the target area is set as another area where the highlight color is not set, and the process returns to S42. When it is determined that the highlight color setting process has been completed for all regions of the input image 10, the highlight color setting process is completed.

  FIG. 11 is a schematic diagram showing a converted image 50 when the above-described highlight color setting process is executed in the second embodiment. Since the display brightness of the area 11 of the input image 10 is equal to or lower than the upper limit brightness Ra (reflectance 400%), a specific color set by the user is set as the highlight color for the area 11. For example, it is assumed that the highlight color of the region 11 is a color indicated by a gradation value (655) corresponding to a display luminance of 300% reflectance.

  The contour region included in the region 11 is colored with a color represented by a gradation value corresponding to display luminance lower than the upper limit luminance Ra. Therefore, the contour region included in the region 11 is not converted into a gradation value corresponding to the upper limit luminance Ra by the range conversion process of the range conversion unit 127. For example, when the upper limit luminance Ra is a reflectance of 400% and the contour region is colored with a gradation value corresponding to the reflectance of 300%, the gradation value of the contour region included in the region 11 is expressed by Equations 1 and 2. And converted to 828.

  The contour region included in the region 12 is colored with an emphasis color represented by a gradation value corresponding to a display luminance equal to or higher than the upper limit luminance Ra. Therefore, the contour region included in the region 12 is converted into a gradation value corresponding to the upper limit luminance Ra by the range conversion process of the range conversion unit 127. For example, when the color corresponding to the reflectance of 600% is set as the emphasized color of the region 12, the gradation value of the contour region included in the region 12 is converted to 1023 from Equation 1 and Equation 2. Therefore, the contour area included in the area 52 of the converted image 50 corresponding to the area 12 is displayed based on the gradation value corresponding to the upper limit luminance Ra.

  According to the image processing apparatus 100 in the second embodiment, in the converted image 50 obtained by converting the input image 10, the contour region included in the region 52 has the upper limit luminance Ra as in the other images included in the region 52. It is displayed in the color represented by the corresponding gradation value. That is, the enhancement process is not substantially performed on the outline region of the region 52. Therefore, by displaying only the outline region in the region 52, it is possible to suppress the user from having a visual discomfort.

(Third embodiment)
The image processing apparatus 100 according to the third embodiment identifies a clip area whose gradation value is larger than the specified gradation value from among a plurality of pixels of the input image, and performs an outline region included in the clip area. , Do not execute the emphasis process.

  The apparatus configuration diagram of the image processing apparatus 100 according to the third embodiment is the same as that according to the first embodiment, and a description thereof is omitted. In the third embodiment, the converted image output flow executed by the control unit 120 is the same as that in the first embodiment except for the edge enhancement process (S5), and thus the description thereof is omitted. For example, it is assumed that the image processing apparatus 100 executes a contour enhancement process and a range conversion process on the input image 10 illustrated in FIG. 4 to generate and output a converted image.

  FIG. 12 is a flowchart showing the contour enhancement processing executed by the control unit 120 in the third embodiment. When the contour enhancement process is started, the enhancement processing unit 126 executes a process for acquiring the input image 10 in S51. The process proceeds to S52.

  In S <b> 52, the enhancement processing unit 126 executes a process of acquiring information related to the contour region specified by the contour region specifying unit 123. The process proceeds to S53.

  In S <b> 53, the clip area specifying unit 122 specifies an area composed of pixels having a gradation value corresponding to display luminance higher than the upper limit luminance Ra set by the display range setting unit 125 in the input image as a clip area. Execute the process. The process proceeds to S54.

  In the process from S54, the enhancement processing unit 126 determines whether or not each of the plurality of areas of the input image 10 is a clip area, and performs a process of coloring a contour area that is not a clip area in the input image 10 with an emphasized color. Run. Assume that the plurality of regions of the input image 10 for which the enhancement processing unit 126 determines whether it is a clip region or a contour region is, for example, each pixel of the input image 10. Note that the plurality of regions may be regions composed of a plurality of pixels obtained by dividing the input image 10.

  In S <b> 54, the enhancement processing unit 126 executes processing for determining whether the target region is a clip region among the plurality of regions. If the target area is a clip area, the process proceeds to S55. If the target area is not a clip area, the process proceeds to S56.

  In step S55, the enhancement processing unit 126 executes processing for determining whether or not processing has been completed for a plurality of regions of the input image 10. When it is determined that the processing has not been completed for a plurality of regions of the input image 10, the enhancement processing unit 126 changes the target region to a region that has not been processed among the plurality of regions of the input image 10. Then, the process returns to S54.

  If it is determined in S54 that the target area is not a clip area, in S56, the emphasis processing unit 126 executes processing for determining whether or not the target area is a contour area. If it is determined that the target area is an outline area, the process proceeds to S57. If it is determined that the target area is not a contour area, the process proceeds to S55. The process of S55 is as described above.

  In step S <b> 57, the enhancement processing unit 126 executes a process of coloring the target region with the enhancement color set by the enhancement color setting unit 124. Note that the highlight color setting unit 124 can set an arbitrary color as the highlight color. For example, it is assumed that the emphasized color setting unit 124 sets a color represented by a gradation value corresponding to a display luminance with a reflectance of 300% as an emphasized color. The process proceeds to S55.

  By executing the above-described contour enhancement process, the image processing apparatus 100 according to the third embodiment performs the enhancement process only on the contour region that is not included in the clip region larger than the upper limit luminance Ra in the input image 10. To do. For example, when the image processing apparatus 100 of the third embodiment generates a converted image based on the input image 10 shown in FIG. 4, the output converted image is the same as that in FIG. Therefore, it is possible to prevent the user from feeling visually uncomfortable by displaying the outline region in the region where the display luminance is higher than the upper limit luminance Ra and the gradation is deteriorated by the range conversion process. Become.

(Fourth embodiment)
The image processing apparatus 100 according to the fourth embodiment identifies a clip area whose gradation value is larger than the specified gradation value from among a plurality of pixels of the input image, and applies to the outline area included in the clip area. The process for specifying the contour region is not executed.

  The apparatus configuration diagram of the image processing apparatus 100 according to the fourth embodiment is the same as that according to the first embodiment, and a description thereof is omitted. In the fourth embodiment, the converted image output flow executed by the control unit 120 is the same as that of the first embodiment except for the contour specifying process (S3), and thus the description thereof is omitted. For example, it is assumed that the image processing apparatus 100 executes a contour enhancement process and a range conversion process on the input image 10 illustrated in FIG. 4 to generate and output a converted image.

  FIG. 13 is a flowchart showing a contour region specifying process executed by the control unit 120 in the fourth embodiment. When the contour emphasis process (S3) is started, the contour area specifying unit 123 executes a process of acquiring the input image 10 in S31. The process proceeds to S32.

  In S <b> 32, the contour region specifying unit 123 executes processing for detecting the contour region of the input image 10. The process proceeds to S33.

  In S <b> 33, the clip area specifying unit 122 specifies an area composed of pixels having gradation values corresponding to display luminance higher than the upper limit luminance Ra set by the display range setting unit 125 in the input image 10 as the clip area. Execute the process. The process proceeds to S34.

  In the processing from S34, the contour region specifying unit 123 determines whether or not each of the plurality of regions of the input image 10 is a clip region, further determines whether or not a contour is detected, and specifies the contour region. Execute the process. Assume that the plurality of regions of the input image 10 for which the contour region specifying unit 123 determines whether or not a clip region or a contour is detected are, for example, each pixel of the input image 10. Note that the plurality of regions may be regions composed of a plurality of pixels obtained by dividing the input image 10.

  In S <b> 34, the contour area specifying unit 123 executes a process of determining whether or not the target area is a clip area among the plurality of areas. If the target area is a clip area, the process proceeds to S35. If the target area is not a clip area, the process proceeds to S36.

  In S35, a process of determining whether or not the contour area specifying process has been completed for a plurality of areas of the input image 10 is executed. When it is determined that the contour region specifying process has not been completed for a plurality of regions of the input image 10, the enhancement processing unit 126 selects the target region as a region that has not been processed among the plurality of regions of the input image 10. And return to the process of S34.

  If it is determined in S34 that the target region is not a clip region, in S36, the contour region specifying unit 123 executes processing for determining whether or not the target region is a region in which a contour is detected. If it is determined that the target region is a region where an outline is detected, the process proceeds to S37. On the other hand, if it is determined that the target region is not the region where the contour is detected, the process proceeds to S35. The process of S35 is as described above.

  In S <b> 37, the contour region specifying unit 123 executes processing for specifying the target region as a contour region. The process proceeds to S35.

  By executing the above-described contour enhancement processing, the image processing apparatus 100 according to the fourth embodiment uses, as the contour region, a region in the input image 10 where a contour included in a clip region larger than the upper limit luminance Ra is displayed. Not specified. Therefore, in the contour emphasis process (S5), the contour included in the clip area larger than the upper limit luminance Ra is not subjected to the emphasis process. For example, when the image processing apparatus 100 of the fourth embodiment generates a converted image based on the input image 10 shown in FIG. 4, the output converted image is the same as that in FIG. Therefore, it is possible to prevent the user from feeling visually uncomfortable by displaying the outline region in the region where the display luminance is higher than the upper limit luminance Ra and the gradation is deteriorated by the range conversion process. Become.

(Other embodiments)
In the above-described embodiment, the input image 10 is described as a monochrome image in which only the gradation value corresponding to the luminance is designated for each pixel. However, the format of the input image 10 is not limited to this. The input image 10 may include red, green, and blue subpixels for each pixel, and a gradation value may be designated for each subpixel. Further, the input image 10 may be one in which brightness (Y) and color difference (Cr, Cb) are designated for each pixel.

  The present invention is also realized by executing the following processing. This is a process in which software (program) for realizing the functions of the above-described embodiments is supplied to a system or apparatus via a network or various recording media, and a computer of the system or apparatus reads and executes the program code. The computer may be an arithmetic processing unit such as a CPU or MPU. In this case, the program and a recording medium readable by the computer of the system or apparatus storing the program constitute the present invention.

DESCRIPTION OF SYMBOLS 10 Input image 30 Conversion image 100 Image processing apparatus 110 Input part 120 Control part 121 Input processing part 124 Highlighting color setting part 126 Enhancement processing part 127 Range conversion part 128 Output processing part 130 Output part 200 Camera 300 Display part

Claims (19)

Obtaining means for obtaining an input image having a plurality of pixels;
Emphasis means for applying an emphasis process for coloring and emphasizing the outline region of the input image;
Setting means for setting an emphasis color used in the coloring of the emphasis process;
Conversion means for converting the gradation value of the input image subjected to the enhancement processing to generate a converted image;
With
The converting means converts a gradation value of a pixel having a gradation value equal to or lower than a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that the converted image can take. Generating the converted image;
When the gradation value of the contour region of the input image is larger than the predetermined gradation value, the setting means corresponds to the emphasized color of the contour region to a gradation value equal to or greater than the predetermined gradation value. An image processing apparatus characterized by having a color.   2. The image processing apparatus according to claim 1, wherein the setting unit sets an emphasis color for all the outline regions of the input image to a color corresponding to a gradation value equal to or greater than the predetermined gradation value. . A first specifying means for specifying a first region of pixels of which the gradation value is larger than the predetermined gradation value in the input image;
The setting means sets an emphasis color of a contour area included in the first area of the input image as a color corresponding to a gradation value equal to or higher than the predetermined gradation value, and the first image of the input image The image processing apparatus according to claim 1, wherein an emphasis color of a contour area included in a second area that is not an area is set to a color corresponding to a gradation value smaller than the predetermined gradation value. Obtaining means for obtaining an input image having a plurality of pixels;
Emphasis means for applying an emphasis process for coloring and emphasizing the outline region of the input image;
Setting means for setting an emphasis color used in the coloring of the emphasis process;
Conversion means for converting the gradation value of the input image subjected to the enhancement processing to generate a converted image;
With
The converting means converts a gradation value of a pixel having a gradation value equal to or lower than a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that the converted image can take. Generating the converted image;
The image processing apparatus according to claim 1, wherein the enhancement unit does not perform the enhancement process on a contour region having a gradation value larger than a predetermined gradation value in the input image. A first specifying means for specifying a first region of pixels of which the gradation value is larger than the predetermined gradation value in the input image;
The highlighting means is
Executing the enhancement process on the contour region included in the first region of the input image;
The image processing apparatus according to claim 4, wherein the enhancement processing is not performed on the contour region that is not included in the first region in the input image. A first specifying unit that specifies a first region of pixels of which the gradation value is larger than the predetermined gradation value in the input image;
Second specifying means for specifying the contour region of the input image,
The image processing apparatus according to claim 4, wherein the second specifying unit does not execute a process of specifying the contour region for the first region in the input image.   The converting means converts a gradation value of a pixel having a gradation value larger than a predetermined gradation value among the plurality of pixels of the input image into a maximum gradation value that can be taken by the converted image. And converting a gradation value of a pixel having a gradation value equal to or lower than a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that can be taken by the converted image. The image processing apparatus according to claim 1. The gradation value of the input image and the gradation value of the converted image are associated with luminance,
The predetermined gradation value is a gradation value of the input image corresponding to an upper limit of luminance that can be taken by the converted image,
8. The conversion unit according to claim 1, wherein the conversion unit is a process of converting a luminance range that can be taken by the input image into a luminance range that can be taken by the converted image. Image processing apparatus. The image processing apparatus according to any one of claims 1 to 8,
Display means for displaying an image based on the converted image;
A display device comprising: An acquisition step of acquiring an input image having a plurality of pixels;
An emphasis step for applying an emphasis process for coloring and emphasizing the contour region of the input image;
A setting step for setting an emphasis color used in the coloring of the emphasis process;
A conversion step of generating a converted image by converting a gradation value of the input image subjected to the enhancement process;
With
The converting step converts a gradation value of a pixel having a gradation value equal to or lower than a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that can be taken by the converted image. Generating the converted image;
In the setting step, when the gradation value of the contour region of the input image is larger than the predetermined gradation value, the emphasized color of the contour region corresponds to a gradation value equal to or higher than the predetermined gradation value. A control method for an image processing apparatus, characterized in that the color is used.   The image processing apparatus according to claim 10, wherein the setting step sets an emphasis color for all the contour regions of the input image to a color corresponding to a gradation value equal to or greater than the predetermined gradation value. Control method. A first specifying step of specifying a first region composed of pixels having a gradation value larger than the predetermined gradation value in the input image;
The setting step sets an emphasis color of a contour region included in the first region of the input image as a color corresponding to a gradation value equal to or higher than the predetermined gradation value, and the first image of the input image The control method of the image processing apparatus according to claim 10, wherein an emphasis color of a contour area included in a second area that is not an area is set to a color corresponding to a gradation value smaller than the predetermined gradation value. . An acquisition step of acquiring an input image having a plurality of pixels;
An emphasis step for applying an emphasis process for coloring and emphasizing the contour region of the input image;
A setting step for setting an emphasis color used in the coloring of the emphasis process;
A conversion step of generating a converted image by converting a gradation value of the input image subjected to the enhancement process;
With
The converting step converts a gradation value of a pixel having a gradation value equal to or lower than a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that can be taken by the converted image. Generating the converted image;
The method of controlling an image processing apparatus, wherein the enhancement step does not execute the enhancement process on a contour region having a gradation value larger than a predetermined gradation value in the input image. A first specifying step of specifying a first region composed of pixels having a gradation value larger than the predetermined gradation value in the input image;
The enhancement step performs the enhancement process on the contour region included in the first region in the input image, and the contour region not included in the first region in the input image. The method according to claim 13, wherein the enhancement process is not executed. A first specifying step of specifying a first region of pixels of which the gradation value is larger than the predetermined gradation value in the input image;
A second specifying step of specifying the contour region of the input image,
The method of controlling an image processing apparatus according to claim 13, wherein the second specifying step does not execute a process of specifying the contour region for the first region in the input image.   The converting step converts a gradation value of a pixel having a gradation value larger than a predetermined gradation value among the plurality of pixels of the input image to a maximum gradation value that can be taken by the converted image. And converting a gradation value of a pixel having a gradation value equal to or lower than a predetermined gradation value among the plurality of pixels of the input image into a range of gradation values that can be taken by the converted image. The method for controlling an image processing apparatus according to claim 10. The gradation value of the input image and the gradation value of the converted image are associated with luminance,
The predetermined gradation value is a gradation value of the input image corresponding to an upper limit of luminance that can be taken by the converted image,
17. The conversion process according to claim 10, wherein the converting step is a process of converting a luminance range that can be taken by the input image into a luminance range that can be taken by the converted image. Method for controlling the image processing apparatus.   A program that can be executed by an arithmetic processing device capable of executing the steps of the control method for an image processing device according to any one of claims 10 to 17.   A recording medium readable by an arithmetic processing unit on which the program according to claim 18 is recorded.

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