JP5474113B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to a print preview technique for displaying a print result on a screen in advance.

  Conventionally, there is a print preview technique for displaying a print result on a display in advance and confirming the print result when printing an image on a recording medium (print medium) (for example, Patent Document 1). That is, the user can know in advance the layout state of the characters / images to be recorded on the recording medium.

  By the way, there are various types of recording media, such as coated paper and art paper, and the color of the printed media and the texture of the media itself are different. For this reason, a preview including the color and texture of the print result corresponding to the recording medium in addition to the layout state described above is desired.

  On the other hand, Patent Document 2 discloses a technique for switching and displaying frame images to display a texture. Specifically, a plurality of frame images obtained by performing brightness processing on a subject image obtained by changing illumination conditions in advance are switched and displayed. Since the light reflection state changes when the illumination condition changes, it is possible to check the texture of the subject surface, such as subtle unevenness and gloss, on the image display.

Japanese Patent Laid-Open No. 10-40045 JP 2003-132350 A

  However, in the frame image display technique, it is necessary to prepare frame images under various conditions in advance. Specifically, it is necessary to acquire a subject image in which the subject is illuminated by changing the position of the light source or the illumination direction. Further, when a large number of colors can be included as in the print preview, the same number of subject images as the number of colors that can be output is required, and there is a problem that the amount of data required is enormous.

  The present invention has been made in view of the above problems, and an object thereof is to solve at least one of the above problems.

In order to solve the above-described problems, the image processing apparatus of the present invention has the following configuration. That is, in an image processing apparatus that generates a preview image when an image is formed on a recording medium by the image forming apparatus, the spectral reflectance of the color patch formed on the recording medium by the recording agent used by the image forming apparatus is Spectral reflectance acquisition means for acquiring information, image data input means for inputting image data of an image formed on the recording medium, and condition input means for receiving input of illumination conditions and observation conditions when generating a preview image And deriving pixel values at each position using the color of the image formed by the image data and the information of the spectral reflectance based on the input illumination condition and the observation condition. and a generating means for generating, said generating means, the spectral radiance of the incident light on the recording medium Wherein by integrating with respect to the solid angle of the predetermined range the product of the spectral reflectance derived the pixel value at each position, and generates the preview image and. Alternatively, in an image processing apparatus that generates a preview image when an image is formed on a recording medium by the image forming apparatus, the spectral reflectance of the color patch formed on the recording medium by the recording agent used by the image forming apparatus is Spectral reflectance acquisition means for acquiring information, image data input means for inputting image data of an image formed on the recording medium, and condition input means for receiving input of illumination conditions and observation conditions when generating a preview image And deriving pixel values at each position using the color of the image formed by the image data and the information of the spectral reflectance based on the input illumination condition and the observation condition. Generating means, wherein the generating means has an image formed on the recording medium. The sum of the spectral reflectance obtained by multiplying the spectral reflectance of the region with the pixel value based on the observation condition and the spectral reflectance for the color patch is calculated and the sum of the incident light on the recording medium is calculated. By integrating the product of the spectral radiance with a solid angle within a predetermined range, a pixel value at each position is derived, and the preview image is generated.

  According to the present invention, it is possible to provide a technique capable of generating a high-quality preview image based on less data.

1 is a diagram illustrating a configuration of an image processing system according to a first embodiment. It is a whole flowchart of simulation image generation concerning a 1st embodiment. It is a detailed flowchart of generation of a simulation image. It is a conceptual diagram of an incident light direction and an observation direction with respect to a virtual recording medium. It is a figure which shows the structure of the image processing apparatus which concerns on 2nd Embodiment. It is a whole flowchart of simulation image generation concerning a 2nd embodiment. It is a figure which shows an example of a user interface.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are merely examples, and are not intended to limit the scope of the present invention.

(First embodiment)
An image processing system including an image processing apparatus that generates a preview image will be described below as an example of the first embodiment of the image processing system according to the present invention.

<System configuration>
FIG. 1 is a diagram illustrating a configuration of an image processing system according to the first embodiment.

  Reference numeral 111 denotes a spectral reflectance measuring device (colorimeter) that measures the spectral reflectance of ink on the recording medium. It is desirable that the light measured by the spectral reflectance measuring device 111 does not include surface reflected light. In order to reduce the surface reflection light, for example, the recording medium may be irradiated with light at an angle of 45 degrees and measurement may be performed in a direction away from the regular reflection direction (for example, the front direction of the recording medium).

  Reference numeral 112 denotes a variable angle photographing image capturing device configured to be able to acquire images of a recording medium from various directions. That is, an image showing a texture such as subtle unevenness or gloss on the surface of the recording medium is acquired. Therefore, the image of the recording medium is acquired by changing at least one of the angle of the photographing unit (not shown) and the recording medium of the variable angle photographing image photographing device 112 or the angle of the lighting unit (not shown) and the recording medium. That is, an image of each recording medium in which the relative positional relationship between the incident direction of illumination and the shooting direction is changed is acquired. In order to reduce the variation in the angle of incident light depending on the position of the recording medium, it is desirable to irradiate the recording medium with parallel light.

  Reference numeral 113 denotes a surface reflected light measuring device, which measures the spectral reflectance of the surface reflected light of the recording medium. Note that it is desirable to output the spectral radiance in the regular reflection direction when the medium is illuminated from a certain angle as a value normalized by the spectral radiance of the illumination.

  Further, in the measurement by the variable angle photographing image photographing device 112 and the surface reflected light measuring device 113, it is desirable to photograph or measure by reducing the diffuse reflection component using a polarizing plate or the like.

  Reference numeral 114 denotes an illumination observation condition input device that inputs illumination observation conditions. Specifically, a setting for calculating a simulation image under what conditions such as an observation angle and illumination conditions is received from the user. Here, the image processing apparatus 101 is described as a separate configuration, but of course, it may be configured using software operating on the image processing apparatus 101 and an input unit such as a keyboard and a mouse.

  Reference numeral 101 denotes an image processing apparatus, which includes a personal computer (PC). The image processing apparatus 101 controls each of the above-described apparatuses to acquire data related to the recording medium, and then generates a preview image (simulation image). The image processing apparatus 101 includes functional units described below.

  Reference numeral 121 denotes a spectral reflectance acquisition unit that acquires information such as measured values of spectral reflectance of ink from the spectral reflectance measuring device 111 (spectral reflectance acquisition means). Reference numeral 122 denotes a variable angle captured image acquisition unit that acquires a captured image from the variable angle captured image capturing device 112 (media image acquisition means). Reference numeral 123 denotes a surface reflected light acquisition unit that acquires information such as a measured value of the spectral reflectance of the surface reflected light from the surface reflected light measurement device 113 (spectral reflectance acquisition means).

  An illumination observation condition acquisition unit 124 acquires an illumination observation condition input via the illumination observation condition input device 114. Reference numeral 131 denotes a simulation data storage unit that stores various data serving as a basis for calculating a simulation image. Here, the various types of data include, in addition to data acquired from each of the above-described devices, for example, a color conversion profile for displaying on a simulation image display device 161 described later, or a color conversion for printing with a printing device (not shown). Includes profiles. It is also assumed that print image data to be printed on the recording medium is also stored.

  Reference numeral 141 denotes an image calculation unit that calculates a simulation image based on various data stored in the simulation data storage unit 131. Reference numeral 151 denotes a simulation image storage unit that stores the simulation image generated by the image calculation unit 141. Note that the simulation data storage unit 131 and the simulation image storage unit 151 may be physically realized by the same storage device (such as an HDD). Reference numeral 161 denotes a simulation image display device that displays a simulation image.

<Operation of the device>
FIG. 2 is an overall flowchart of simulation image generation according to the first embodiment. The following steps are triggered by a user's request for generating a simulation image to the image processing apparatus 101.

  In step S201, the spectral reflectance measuring device 111 measures the spectral reflectance of a color printed in advance on a recording medium. Specifically, the spectral reflectance is measured for a color patch formed on a recording medium with a recording agent (ink or toner) used in the printing apparatus. Although it is desirable to measure all colors that can be output by the printing device, in order to reduce the amount of data, only the colors specified in advance are measured, and for other colors, the measured values are interpolated and spectral reflection is performed. You may ask for the rate. In this case, however, at least three colors are measured so that interpolation is possible. For example, it may be configured to measure only the color patches formed by each of the colors (for example, yellow, magenta, and cyan) of the recording agent used in the image forming apparatus.

  Thereafter, the spectral reflectance acquisition unit 121 acquires the measurement value measured by the spectral reflectance measurement device 111 and stores it in the simulation data storage unit 131.

  In step S202, it is determined whether or not the measurement has been completed for the number of colors designated in advance in step S201. If completed, the process proceeds to step S203, and if not completed, the process returns to step S201.

  In step S <b> 203, the variable angle captured image capturing apparatus 112 captures a variable angle captured image on a recording medium. Here, it is desirable that the variable angle shooting image shooting device 112 sets the illumination unit and the shooting unit at various angles and performs shooting each time. However, in order to reduce the data amount, shooting may be performed with thinning. . The variable angle photographed image is obtained as one two-dimensional grayscale image with respect to an angle of a certain illumination unit and photographing unit.

  Note that the variable angle captured image acquisition unit 122 preferably acquires the variable angle captured image as a reflectance image of the recording medium. In order to obtain the reflectance image, for example, the acquired recording media image may be normalized based on a photographed image of a sample whose reflectance is known. Thereafter, the variable angle captured image acquisition unit 122 acquires one or more variable angle captured images acquired by the variable angle captured image imaging device 112 and stores the acquired one in the simulation data storage unit 131.

  In step S204, the surface reflected light measuring device 113 measures the spectral reflectance of the surface reflected light of the recording medium. Thereafter, the surface reflected light acquisition unit 123 acquires the measurement value measured by the surface reflected light measurement device 113 and stores it in the simulation data storage unit 131.

  In step S <b> 205, the illumination observation condition input device 114 receives a setting of what observation angle and illumination condition the simulation image is calculated from the user. Thereafter, the illumination observation condition acquisition unit 124 stores the observation angle and the illumination condition received by the illumination observation condition input device 114 in the simulation data storage unit 131.

  In addition, as illumination conditions, the spectral radiance of incident light with respect to various angles, etc. are received. However, illumination conditions (parameter sets) for a plurality of scenes such as “office” and “outdoor” may be stored in advance in a storage unit (not shown) in the illumination observation condition input device 114. In that case, the user can input the lighting conditions simply by selecting and inputting the scene.

  In step S206, the image calculation unit 141 generates a simulation image based on the above-described various data stored in the simulation data storage unit 131. Details of generation of the simulation image will be described later.

  In step S207, the simulation image generated in step S206 is stored in the simulation image storage unit 151.

  In step S208, the simulation image display device 161 acquires and displays the simulation image stored in step S207.

<Generation of simulation image>
FIG. 3 is a detailed flowchart of simulation image generation (step S206). The image calculation unit 141 generates a simulation image by sequentially calculating and assigning pixel values to the surface of a virtual recording medium configured in a memory (not shown).

  In step S301, the observation direction ω for the virtual recording medium is set based on the illumination observation condition stored in the simulation data storage unit 131.

  In step S302, the spectral radiance L (λ) of the incident light beam is read based on the illumination observation condition stored in the simulation data storage unit 131.

  In step S303, the spectral reflectance A (λ) of the media surface reflected light stored in the simulation data storage unit 131 is read.

  The following steps are executed for each surface position (x, y) on the virtual recording medium.

In step S304, the print image data stored in the simulation data storage unit 131 is read (image data input means), and the color λ ₀ to be recorded at the surface position (x, y) is derived. Then, the spectral reflectance R _D of the recording material corresponding to the color lambda ₀ which was derived _{(lambda 0),} on the basis of the spectral reflectivity R _D of the recording material stored in the simulation data storage unit 131 _(lambda) is derived.

In step S <b> 305, based on the illumination observation condition stored in the simulation data storage unit 131, the corresponding variable angle photographed image is read from the simulation data storage unit 131. Then, the pixel value R _S (x ₀ , y ₀ , ω, ω ′) corresponding to the surface position (x, y) is read from the read variable-angle image.

In step S306, the spectral radiance I (x, y, λ) of light emitted in the observation direction is derived from the surface position (x ₀ , y ₀ ) of the virtual recording medium. Here, the spectral radiance I (x, y, λ) at the surface position (x ₀ , y ₀ ) is derived based on the following formula.

ここで、数式中、Ωに対する積分とは全立体角に対する積分を意味する。また、上述の式中の記号の意味は以下の通りである。また、図４に仮想の記録メディアに対する入射光線方向、観察方向の概念図を示す。

Here, in the formula, the integration with respect to Ω means the integration with respect to all solid angles. The meanings of the symbols in the above formula are as follows. FIG. 4 shows a conceptual diagram of the incident light direction and the observation direction with respect to the virtual recording medium.

ω: incident light direction ω ′: observation direction θ: angle formed between the normal line of the virtual recording medium and the incident light direction x ₀ , y ₀ : variable angle imaging corresponding to the surface position (x, y) of the virtual recording medium Pixel position on the image L (λ): Spectral radiance of incident light R _D (λ): Spectral reflectance of ink A (λ): Spectral reflectance of surface reflected light of recording medium Here, for each pixel The spectral radiance I (x, y, λ) is obtained, but it is actually preferable to convert it to a colorimetric value such as a tristimulus value. More preferably, conversion from tristimulus values to RGB pixel values is performed based on a color conversion profile corresponding to the simulation image display device 161 when displaying a simulation image.

  In step S307, it is determined whether pixel values have been derived for all regions (all pixels) in the virtual recording medium. If it is derived for all the pixels, the simulation image calculation is completed. If it is not derived but remains, the process returns to step S304, and pixel values are sequentially derived for the next surface position.

  Based on the above steps, pixel values are derived for all pixels on the virtual recording medium. As a result, the spectral radiance of light emitted from each position on the surface of the virtual recording medium in the observation direction can be obtained. That is, the preview image is completed.

  As described above, according to the first embodiment, a preview image in a desired observation environment and illumination environment selected by the user can be displayed. That is, the user can confirm the image as a higher quality image such as the color / texture of the recording medium. On the other hand, since it is not necessary to perform the variable angle photographic image for all colors, it is possible to reduce the amount of data necessary for generating the preview image as compared with the conventional case.

  In the image processing system according to the first embodiment, the actual recording medium is measured in real time by various measuring devices provided outside the image processing apparatus. Therefore, there is an advantage that a preview image can be displayed on an arbitrary recording medium as long as the actual recording medium exists.

(Second Embodiment)
In the second embodiment, data for several types of recording media are stored in advance in a database. Then, at the time of simulation (that is, at the time of preview image generation), the type of the recording medium is selected via the user interface (UI), and various data corresponding to the selected recording medium are read from the database.

<Device configuration>
FIG. 5 is a diagram illustrating a configuration of the image processing apparatus according to the second embodiment.

  In the first embodiment, the spectral reflectance measuring device 111, the variable angle photographing image photographing device 112, and the surface reflected light measuring device 113 are a database (DB) that stores data acquired by each of these devices. Is mainly different. That is, various data related to the recording medium shown in the first embodiment is stored in advance in a database using each device. In FIG. 5, the database is directly connected to the image processing apparatus 501, but for example, various databases may be distributed on the Internet. In addition, various data may be stored in the same physical device.

  The illumination observation condition input device 514 receives an input of a recording medium to be printed in addition to the observation angle and the illumination condition. Correspondingly, the illumination observation condition acquisition unit 524 includes a communication unit 502 that notifies an identifier of a recording medium to be printed to the spectral reflectance acquisition unit 521, the variable angle captured image acquisition unit 522, and the surface reflected light acquisition unit 523. ing.

  Since the other units and the functional units in the image processing apparatus 501 are substantially the same as the corresponding units in the first embodiment, detailed description thereof will be omitted.

<Setting / Preview Image Display UI>
FIG. 7 is a diagram illustrating an example of a UI (user interface) used for setting a recording medium, an observation angle, an illumination condition, and a preview image display. The UI is displayed on the display screen of the simulation image display device 561, for example.

  Reference numeral 701 denotes a preview image display unit that displays a simulation image stored in 551. Reference numeral 702 denotes a preview condition setting display unit. Specifically, the currently specified illumination conditions, media, and observation angle conditions are displayed. That is, the user can view the preview image for the set condition by operating the illumination observation condition input device 514 while viewing the UI.

<Operation of the device>
FIG. 6 is an overall flowchart of simulation image generation according to the second embodiment. The following steps are triggered by a request for generating a simulation image to the image processing apparatus 501 by the user.

  In step S <b> 601, the illumination observation condition input device 514 receives a setting for generating a simulation image under what kind of medium, observation angle, and illumination condition from the user. Thereafter, the illumination observation condition acquisition unit 524 reads the image processing apparatus 501 and stores it in the simulation data storage unit 531. That is, the setting from the user is accepted interactively through the UI shown in FIG. Thereafter, the illumination observation condition acquisition unit 524 notifies the acquired recording medium identifier to the spectral reflectance acquisition unit 521, the variable-angle captured image acquisition unit 522, and the surface reflected light acquisition unit 523 via the communication unit 502.

  Note that only the recording medium and the illumination conditions may be set by 514, and the observation angle may be configured to be automatically generated continuously by the illumination observation condition acquisition unit 524. Furthermore, the observation angle that is automatically generated may be calculated based on the illumination conditions. In that case, it is desirable to set the observation angle so that it is in the vicinity of the regular reflection direction with respect to the direction of the incident light beam having the highest luminance under the illumination conditions.

  In step S602, the spectral reflectance acquisition unit 521 reads spectral reflectance data corresponding to the recording medium from the spectral reflectance DB 511 using the identifier of the recording medium input via the communication unit 502. Then, the spectral reflectance data is stored in the simulation data storage unit 531.

  In step S603, the variable angle captured image acquisition unit 522 reads the variable angle captured image data corresponding to the recording medium from the variable angle captured image DB 512 using the identifier of the recording medium input via the communication unit 502. Then, the variable angle photographed image data is stored in the simulation data storage unit 531.

  In step S604, the surface reflected light acquisition unit 523 reads the spectral reflectance data corresponding to the recording medium from the surface reflected light DB 513 using the identifier of the recording medium input via the communication unit 502. Then, the spectral reflectance data is stored in the simulation data storage unit 531.

  In step S <b> 605, the image calculation unit 541 generates a simulation image based on the above-described various data stored in the simulation data storage unit 531. Note that the details of the generation of the simulation image are the same as those in the first embodiment, and a description thereof will be omitted.

  In step S606, the simulation image generated in step S605 is stored in the simulation image storage unit 551.

  In step S607, the simulation image display device 561 acquires and displays the simulation image stored in step S606. That is, the image is displayed on the preview image display unit 701 in FIG.

  As described above, according to the second embodiment, a preview image in the recording medium, observation environment, and illumination environment selected by the user can be displayed. That is, the user can confirm the image as a higher quality image such as the color / texture of the recording medium. On the other hand, since it is not necessary to perform the variable angle photographic image for all colors, it is possible to reduce the amount of data necessary for generating the preview image as compared with the conventional case.

  Further, unlike the first embodiment, it is possible to generate a preview image even if there is no sample of the recording medium on the spot.

(Other embodiments)
Although the embodiments of the present invention have been described in detail above, the present invention may be applied to a system constituted by a plurality of devices or may be applied to an apparatus constituted by one device.

  The present invention can also be achieved by supplying a program that realizes the functions of the above-described embodiments directly or remotely to a system or apparatus, and the system or apparatus reads and executes the supplied program code. The Accordingly, the program code itself installed in the computer in order to realize the functional processing of the present invention by the computer is also included in the technical scope of the present invention.

  In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.

  Examples of the recording medium for supplying the program include a floppy (registered trademark) disk, a hard disk, an optical disk (CD, DVD), a magneto-optical disk, a magnetic tape, a nonvolatile memory card, and a ROM.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. In addition, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can also be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

Claims (8)

An image processing apparatus that generates a preview image when an image is formed on a recording medium by an image forming apparatus,
Spectral reflectance acquisition means for acquiring spectral reflectance information for color patches formed on the recording medium by the recording agent used by the image forming apparatus;
Image data input means for inputting image data of an image formed on the recording medium;
Condition input means for receiving input of illumination conditions and observation conditions when generating a preview image;
Based on the input illumination condition and observation condition, a preview image is generated by deriving a pixel value at each position using the color of the image formed from the image data and the spectral reflectance information. Generating means for
Equipped with a,
The generation means derives a pixel value at each position by integrating a product of a spectral radiance of a light ray incident on the recording medium and the spectral reflectance with respect to a solid angle within a predetermined range, and the preview An image processing apparatus that generates an image. An image processing apparatus that generates a preview image when an image is formed on a recording medium by an image forming apparatus,
Spectral reflectance acquisition means for acquiring spectral reflectance information for color patches formed on the recording medium by the recording agent used by the image forming apparatus;
Image data input means for inputting image data of an image formed on the recording medium;
Condition input means for receiving input of illumination conditions and observation conditions when generating a preview image;
Based on the input illumination condition and observation condition, a preview image is generated by deriving a pixel value at each position using the color of the image formed from the image data and the spectral reflectance information. Generating means for
Equipped with a,
The generation means includes a spectral reflectance obtained by multiplying a spectral reflectance of a region where no image is formed on the recording medium by a pixel value based on the observation condition, and a spectral reflectance for the color patch. Taking the sum and integrating the product of the sum and the spectral radiance of the light rays incident on the recording medium with respect to a predetermined range of solid angles, deriving pixel values at each position, and An image processing apparatus that generates the image processing apparatus. The spectral reflectance acquisition means further image processing apparatus according to claim 1 or 2, characterized in that to obtain the information of the spectral reflectance for the area where no image is formed on the recording medium. The illumination condition, the image processing apparatus according to claim 1 or 2, characterized in that it corresponds to the spectral radiance of the incident light on the recording medium. The image processing apparatus according to claim 2 , wherein the pixel value based on the observation condition is obtained by photographing the recording medium. An image processing method for generating a preview image when an image is formed on a recording medium by an image forming apparatus,
Spectral reflectance acquisition means for acquiring spectral reflectance information for a color patch formed on the recording medium by a recording agent used by the image forming apparatus;
An image data input step for inputting image data of an image to be formed on the recording medium;
A condition input step for receiving input of illumination conditions and observation conditions when the condition input means generates a preview image;
The generation means derives a pixel value at each position using the color of the image formed by the image data and the spectral reflectance information based on the input illumination condition and the observation condition. A generation process for generating a preview image;
Only including,
In the generating step, a pixel value at each position is derived by integrating a product of a spectral radiance of incident light on the recording medium and the spectral reflectance with respect to a solid angle within a predetermined range, and the preview is performed. An image processing method characterized by generating an image. An image processing method for generating a preview image when an image is formed on a recording medium by an image forming apparatus,
Spectral reflectance acquisition means for acquiring spectral reflectance information for a color patch formed on the recording medium by a recording agent used by the image forming apparatus;
An image data input step for inputting image data of an image to be formed on the recording medium;
A condition input step for receiving input of illumination conditions and observation conditions when the condition input means generates a preview image;
The generation means derives a pixel value at each position using the color of the image formed by the image data and the spectral reflectance information based on the input illumination condition and the observation condition. A generation process for generating a preview image;
Only including,
In the generating step, a spectral reflectance obtained by multiplying a spectral reflectance of a region where an image on the recording medium is not formed by a pixel value based on the observation condition and a spectral reflectance for the color patch Taking the sum and integrating the product of the sum and the spectral radiance of the light rays incident on the recording medium with respect to a predetermined range of solid angles, deriving pixel values at each position, and An image processing method comprising generating the image processing method. By executing read into a computer program to function as each unit of the image processing apparatus of any one of claims 1 to 5 the computer.

Images