Patent ID: 12197116

DETAILED DESCRIPTION

Hereinafter, an image exposure device of the present embodiment will be described with reference to the drawings.

First Embodiment

Image Exposure Device

First, the configuration of an image exposure device of the present embodiment will be described.FIG.1shows an exploded perspective view of an example of the image exposure device of the present embodiment. Further,FIG.2shows a cross-sectional view of an example of the image exposure device of the present embodiment.

As shown inFIGS.1and2, an image exposure device10of the present embodiment comprises an image display device12, a support portion21, and a louver film16. The image display device12has a plurality of pixels13. The support portion21supports a photosensitive recording medium14on which a recorded image corresponding to a display image displayed by the image display device12is recorded. The louver film16is provided between the image display device12and the support portion21, and a protective layer17is provided on the support portion21side thereof.

Image Display Device

As the image display device12of the present embodiment, a mobile terminal such as a smartphone and a tablet PC, a liquid crystal display (LCD), an organic light emitting diode (OLED), a cathode ray tube (CRT), a light emitting diode (LED), a plasma display device, or the like can be used.

The image display device12comprises a plurality of pixels13as a display unit32for displaying a display image.FIG.2shows one pixel13as an example of the display unit32. The pixel13is a minimum unit of color information constituting an image display surface. Since the pixel13is provided, the image display device12can display a display image.FIG.3shows an example of the pixel13of the present embodiment. The pixel13includes three sub-pixels. Specifically, as shown inFIG.3, in the pixel13, a sub-pixel13R corresponding to a red (R) color, a sub-pixel13G corresponding to a green (G) color, and a sub-pixels13B corresponding to a blue (B) color are disposed in a row. A plurality of pixels13are arranged two-dimensionally on a pixel display surface of the image display device12. Since the pixel13is provided, the image display device12can display a color display image. The two-dimensional in the arrangement of the pixels13means a state extending in X-Y directions inFIG.1. By setting the distance (pitch) between the adjacent pixels13to 200 μm or less, the impression of the recorded image as a natural image can be strengthened. Therefore, the pitch of the pixel13is preferably 150 μm or less, more preferably 125 μm or less, and even more preferably 85 μm or less.

A glass window26for protecting the pixel13is provided on a surface side irradiated with light from the image display device12. The thickness of the glass window26is preferably thin in order to shorten the distance from the pixel13to the photosensitive recording medium14.

In addition,FIG.4is a block diagram showing an example of a functional configuration of the image display device12of the present embodiment. The image display device12of the present embodiment comprises an image generation unit30, a controller31, and a display unit32.

The image generation unit30of the present embodiment generates a display image in which an image quality of the input image is deteriorated by emphasizing a density difference of a high-frequency component of the input image, and outputs image data representing the generated display image to the controller31.

The controller31causes the display unit32to display a display image represented by the image data input from the image generation unit30. Further, the controller31of the present embodiment generates an image of a red (R) component, an image of a green (G) component, and an image of a blue (B) component from the display image which is a color image. Further, the controller31causes the display unit32to sequentially display the image of the R component, the image of the G component, and the image of the B component in a predetermined order.

The display unit32comprises the above-described pixel13and radiates light according to the display image represented by the pixel13. For the display unit32, for example, a liquid crystal in which a lamp such as a backlight radiates light may be applied, or for example, a light emitting diode in which the display unit32itself radiates light may be applied.

By sequentially displaying each of the image of the R component, the image of the G component, and the image of the B component on the display unit32, the photosensitive recording medium14is sequentially exposed by each of the image of the R component, the image of the G component, and the image of the B component. Hereinafter, this exposure method is referred to as “RGB sequential exposure” for convenience. Although it is referred to as “RGB sequential exposure”, the order of exposure is optional and is not limited to the order of RGB.

Next, a hardware configuration of the image display device12will be described with reference toFIG.5. As shown inFIG.5, the image display device12has a computer comprising a central processing unit (CPU)40, a memory42as a temporary storage area, and a nonvolatile storage unit46. In addition, the image display device12comprises the display unit32described above and an input unit48. The CPU40, the memory42, the storage unit46, the input unit48, and the display unit32are connected via a bus49.

The storage unit46is realized by a hard disk drive (HDD), a solid state drive (SSD), a flash memory, and the like. An image processing program50is stored in the storage unit46as a storage medium. The CPU40reads the image processing program50from the storage unit46, loads the read image processing program50in the memory42, and then executes the image processing program50. In a case where the CPU40executes the image processing program50, the CPU40functions as the image generation unit30and the controller31shown inFIG.4.

Image data of the input image, in other words, image data corresponding to the display image displayed on the display unit32is input to the input unit48. The image data of the input image may be input from the outside of the image display device12or the image exposure device10, or in a case where the image display device12or the image exposure device10itself has a function of forming or capturing an image, the image data formed or captured by itself may be input.

Support Portion

The support portion21of the present embodiment supports the photosensitive recording medium14in a state of being disposed at a position facing the surface irradiated with light from the image display device12. The support portion21may directly or indirectly support the photosensitive recording medium14, and the structure thereof is not particularly limited as long as the support portion21can support the photosensitive recording medium14.

Photosensitive Recording Medium

As shown inFIG.2, the photosensitive recording medium14of the present embodiment has an exposure surface14A. The photosensitive recording medium14is not particularly limited as long as the photosensitive recording medium14can be exposed to light radiated from the image display device12and can form a recorded image. For example, it is possible to use a film pack18or the like to be attached to an instant camera (for example, manufactured by Fujifilm Corporation, Instax (registered trademark), (trade name: Cheki)).

The film pack18is formed by incorporating the photosensitive recording medium14into a case20. A light shielding sheet (not shown) is provided between a plurality of the photosensitive recording mediums14provided in the case20and only the photosensitive recording medium14present on the uppermost surface of the film pack18is exposed by the light shielding sheet. In a case where the film pack18to be attached to the Instax (registered trademark) is applied, the photosensitive recording medium14and the light shielding sheet are incorporated in the film. As a material used for the photosensitive recording medium14, for example, photographic light-sensitive materials such as a negative film, a reversal film, printing paper, and a mono-sheet or peel-apart type instant photographic film can be exemplified.

As shown inFIG.2, a plurality of photosensitive recording medium14is packed in a box-like case20having light shielding properties. In the case20, an exposure aperture22through which light radiated from the image display device12passes is provided in order to expose the exposure surface of the photosensitive recording medium14. In addition, a pressing member (not shown) is provided on the side opposite to the exposure aperture22, and the photosensitive recording medium14is pressed toward the exposure aperture22side by using the pressing member. Therefore, the photosensitive recording medium14is pressed against the periphery of the exposure aperture22, the distance from the image display device12becomes close, and a favorable image can be recorded on the photosensitive recording medium14.

As the case20, a resin member for a recording material that is used for various recording materials such as a photographic light-sensitive material, a magnetic recording material, and an optical recording material can be used. The resin member for the recording material refers to a case, a lid, and an accessory supplemented thereto which are used to contain, pack, coat, protect, transport, or store the recording material, and support the form of the recording material or various members that mount the recording material and exhibit a function.

The photosensitive recording medium14after exposure passes through between developing rollers (not shown), whereby a pod portion provided in the photosensitive recording medium breaks. A development treatment liquid is encapsulated in the pod portion, and the breakage of the pod portion causes the development treatment liquid to spread in the photosensitive recording medium14. After one to several minutes elapses, a development treatment is sufficiently advanced, and a recorded image is formed on the photosensitive recording medium14.

Louver Film

An example of the louver film16of the present embodiment will be described with reference toFIGS.6and7.FIG.6is a schematic cross-sectional view of an example of the image exposure device10of the present embodiment, and is a view for describing a traveling direction of light from the pixel13.FIG.7is a diagram showing a configuration of an example of the louver film16of the present embodiment. A reference numeral16A denotes a planar surface16A of the louver film16, and a reference numeral16B denotes a side surface16B of the louver film16. In the louver film16, light transmission parts102that transmit light and light shielding parts104that shield light are alternately disposed in the first direction (X direction in the planar surface16A inFIG.7) on a surface parallel to an arrangement surface where the pixels13of the image display device12are arranged. The light transmission parts102and the light shielding parts104disposed in the first direction of the present embodiment are examples of first light transmission parts and first light shielding parts of the present disclosure.

In addition, in the louver film16, the light transmission parts102and the light shielding parts104are alternately disposed in the second direction (Y direction in the planar surface16A inFIG.7) perpendicular to the first direction on the surface parallel to the surface where the pixels of the image display device are arranged. The light transmission parts102and the light shielding parts104disposed in the second direction of the present embodiment are examples of second light transmission parts and second light shielding parts of the present disclosure.

In this way, in the present embodiment, the light transmission parts102are two-dimensionally disposed, and the light shielding parts104are formed in a lattice form. With such a configuration, as shown inFIG.6, an angle of light radiated from the pixel13of the image display device12to the exposure surface14A of the photosensitive recording medium14is limited. The louver film16of the present embodiment is an example of a limiting member of the present disclosure.

The light radiated from the pixel13of the image display device12is radiated in all directions of 180° from an image display surface. The radiated light passes through the glass window26provided in the image display device12and is incident on the louver film16. In the light incident on the louver film16, light parallel to a straight line connecting the image display device12and the photosensitive recording medium14passes through the light transmission parts102of the louver film16. In addition, light radiated obliquely to the straight line connecting the image display device12and the photosensitive recording medium14is blocked by the light shielding parts104in the louver film16. By limiting the angle of the light radiated from the image display device12, the image quality of the recorded image recorded on the photosensitive recording medium14is improved.

The light transmission parts102only need to be able to pass through light, and can be provided using a glass material, a transparent silicone rubber, or the like. In addition, portions of the light transmission parts102can be provided as cavities, and the louver film16can be composed of only the light shielding parts104. The light shielding parts104may be a light absorbing member that absorbs light, or a light reflecting member that reflects light. A light shielding member106constituting the light shielding parts104can use a colored resin material such as a black silicone rubber, for example. In addition, as the material that absorbs light, a neutral density filter (ND filter) can be used. The ND filter means a filter having a neutral optical density, and can absorb light evenly in a wavelength region used for exposure without giving an influence on the wavelength (absorbance of 50% or more to 99.999% or less; light transmittance of 0.001% or more to 50% or less).

The configuration of the louver film16is not limited to the present embodiment.FIG.8shows a configuration of another example of the louver film16. The louver film16shown inFIG.7is formed of one layer as shown in the side surface16B, and the light transmission parts102and the light shielding parts104are alternately disposed in the one layer in the first direction and the second direction. Thus, the louver film16with a two-dimensional arrangement is formed.

On the other hand, the louver film16shown inFIG.8is composed of two layers of the first layer118and the second layer119. A reference numeral16B denotes a side surface of the louver film16, a reference numeral118A denotes a planar surface of the first layer118, and a reference numeral119A denotes a planar surface of the second layer119. As shown in the planar surface118A of the first layer118, in the first layer118, the light transmission parts102and the light shielding parts104are alternately disposed only in the first direction (X direction in the planar surface118A inFIG.8). In the second layer119, the light transmission parts102and the light shielding parts104are alternately disposed only in the second direction perpendicular to the first direction (Y direction in the planar surface119A inFIG.8). The first layer118and the second layer119are laminated to form a two-dimensional louver film16. Thus, even in a case where the two-dimensional louver film16is formed with a plurality of layers, the same effect as that of the louver film16formed of one layer can be obtained.

Further, as shown inFIG.9A, the louver film16may have a form in which a protective layer117for preventing the louver film16from being damaged or broken is provided on the surface thereof. Specifically, the louver film16may have a form in which a protective layer117is provided on each of the planar surface118A of the first layer118on the side opposite to the side in contact with the second layer119and the planar surface119A of the second layer119on the side opposite to the side in contact with the first layer118. As shown inFIG.9A, in a case where the protective layer17is provided on both sides of the louver film16, it is possible to make the image defect generated based on the defect or the structure of the louver film16inconspicuous.

The protective layer117is not particularly limited as long as it is transparent and can transmit light. For the protective layer117, for example, a plastic plate formed of an acrylic resin, a polycarbonate, a vinyl chloride resin, or the like can be used.

Furthermore, as shown inFIG.9B, at least one of the light shielding parts104in each column and each row may be composed of a plurality of light shielding members106having intervals. In the example shown inFIG.9B, in the first layer118, each column of light shielding parts104arranged along the first direction has a plurality of light shielding members106provided at predetermined intervals along the second direction. In the second layer119, each row of light shielding parts104arranged along the second direction has a plurality of light shielding members106provided at predetermined intervals along the first direction.

A pitch P of the light shielding parts104of the louver film16is preferably 80 μm or less, and more preferably 65 μm or less. In a case where the pitch P of the light shielding parts104is set to be in the above-described range, it is possible to block obliquely radiated light in light radiated from the pixel13, and to improve the image quality of the recorded image.

The light shielding parts104may be disposed with a difference in an angle between XY axes of the pixel as a reference for the arrangement of the pixel13and an angle between XY axes of the louver as the reference for the arrangement of the light transmission parts102and the light shielding parts104of the louver film16. Moire of the recorded image is suppressed by disposing the pixel13with the difference in the angle between the XY axes of the pixel13and the XY axes of the louver. The difference of the angle is preferably 1 degree to 45 degrees, more preferably 5 degrees to 40 degrees, and even more preferably 10 degrees to 35 degrees.

A thickness t of the louver film16is preferably 1.5 mm or more and 4.0 mm or less, more preferably 2.0 mm or more and 4.0 mm or less, and still more preferably 2.5 mm or more and 4.0 mm or less. By increasing the thickness t of the louver film16, oblique light at a small angle with respect to parallel light can be blocked. In addition, in a case where the thickness t of the louver film16is increased, the recorded image is likely to be blurred and thus, the thickness t of the louver film16is preferably in the above-described range. The thickness t of the louver film16is the thickness of one layer in a case where it is formed of one layer as in the louver film16shown inFIG.7, and the total thickness of a plurality of layers is the thickness of the louver film16in a case where it is formed of the plurality of layers such as two layers of the first layer118and the second layer119as in the louver film16shown inFIGS.8and9.

Protective Layer

The protective layer17is provided on the support portion21side of the louver film16as shown inFIGS.1,2, and6. The protective layer17protects the louver film16in a case where the photosensitive recording medium14and the louver film16are in contact with each other during exposure. The protective layer17prevents the louver film16from being damaged or broken by repeated exposure of the display image displayed on the image display device12to the photosensitive recording medium14.

The protective layer17is not particularly limited as long as it is transparent and can transmit light. For the protective layer17, for example, a plastic plate formed of an acrylic resin, a polycarbonate, a vinyl chloride resin, or the like can be used.

The thickness of the protective layer17is preferably 0.1 μm or more and 500 μm or less. In a case where the thickness of the protective layer17is set to 0.1 μm or more, it is possible to make moire inconspicuous in addition to the effect of protecting the louver film16. In addition, it is possible to make an image defect generated based on the defect or the structure of the louver film16inconspicuous. Further, in a case where the thickness of the protective layer17is set to 500 μm or less, the recorded image can be prevented from being blurred.

Operation of Controller31

Next, an operation of the controller31of the image display device12of the present embodiment will be described.

The spectral characteristics of the light radiated from the image display device12to the photosensitive recording medium14may differ from the spectral sensitivity of the photosensitive recording medium14, specifically, the spectral sensitivity (spectral characteristics) of the sensitive material of the photosensitive recording medium14. In a case where the spectral characteristics of the image display device12and the photosensitive recording medium14are different from each other, the tint of the display image displayed on the image display device12may differ from the tint of the recorded image recorded on the photosensitive recording medium14, that is, the tint of the recorded image exposed by the display image. For example, in the image display device12, an image optimized for the spectral characteristics of the human eye is usually used as a display image. In this way, in a case where the photosensitive recording medium14is exposed to the display image optimized for the spectral characteristics of the human eye, the tint of the recorded image recorded on the photosensitive recording medium14may differ from the tint of the display image. For example, in a case where the photosensitive recording medium14is exposed to a display image having a strong green (G) color tint as the display image, a recorded image whose tint is biased toward the green (G) color can be obtained.

In a case where it is desired to make the tint of the recorded image recorded on the photosensitive recording medium14an image having a desired tint such as an image optimized for the spectral characteristics of the human eye, it is necessary to adjust the tint of the display image displayed on the image display device12in order to expose the photosensitive recording medium14. Therefore, in a case where a recorded image whose tint is biased toward the green (G) color is obtained as described above, for example, the controller31of the present embodiment performs adjustment so that the amount of green (G) light in the display image (exposure image) displayed on the image display device12is reduced.

As an example of a method of adjusting the tint of the display image in the image display device12in order to make the tint of the recorded image recorded on the photosensitive recording medium14a desired tint, there is a method of changing a gradation assignment value of each color of RGB. The case where the display image has a strong green (G) color tint is the case where the exposure amount of green (G) is larger than the exposure amount of other colors in the exposure of the photosensitive recording medium14. In a case where the gradation of the image display device12is 256 gradations, the controller31changes, for example, a gradation assignment value in which the pixel value for green (G) is200in the image data representing the input image to150. That is, in a case where the pixel value for the green (G) color in the input image is “200”, the controller31adjusts the pixel value to “150”. By reducing the gradation assignment value, that is, the pixel value in the display image in this way, the exposure amount of green (G) is reduced, and it is possible to obtain a recorded image whose tint is not biased toward the green (G) color.

That is, by adjusting the gradation assignment value of the color having a strong tint to be small, in other words, by adjusting the pixel value of the color having a strong tint to be small, the exposure amount is reduced, so that it is possible to suppress the bias of the tint in the recorded image.

However, in the case of this adjustment method, originally, the gradation from 0 to 255 is assigned to the gradation less than 0 to 255. That is, it means that the number of gradations in the recorded image is less than 255 gradations. Therefore, so-called gradation skipping, tone jumps, and the like may occur in the recorded image.

A more specific description will be given with reference toFIGS.10and11.FIG.10shows an example of the spectral characteristics of any image display device12. On the other hand,FIG.11shows an example of spectral characteristics of the image display device12adjusted to optimize the tint of the recorded image recorded on any photosensitive recording medium14. In the example shown inFIG.11, as described above, since the tint of the green (G) color is strong in the recorded image, the case where the gradation assignment value of the green (G) color is adjusted is shown. As can be seen by comparingFIGS.10and11, the ratio of the brightness of the green (G) color to the blue (B) color is different, and in the adjusted image display device12shown inFIG.11, the ratio of the brightness of the green (G) color to the blue (B) color is small.

For each of the red (R) color, the green (G) color, and the blue (B) color in the spectral characteristics shown inFIG.10, 256 gradations are assigned to the maximum values of 0 to brightness. In the adjusted spectral characteristics shown inFIG.11, since the maximum value of the brightness of the green (G) color is smaller than that before the adjustment, the gradation value that can be used is smaller than 255. For example, in a case where the gradation assignment to the maximum value of the brightness of the green (G) color in the adjusted spectral characteristics shown inFIG.11is 230, in the adjusted image display device12, the gradations of 231 to 255 cannot be used for the green (G) color.

As described above, in a case where the spectral characteristics of the image display device12and the spectral sensitivity of the photosensitive recording medium14are different from each other, the exposure amount of each of RGB in the display image for exposing the photosensitive recording medium14is not optimized, so that the number of gradations may decrease.

Therefore, the controller31of the present embodiment suppresses the decrease in the number of gradations as described above by optimizing the exposure amount of each of RGB in the display image for exposing the photosensitive recording medium14. Specifically, the controller31optimizes the exposure amount of each of RGB by optimizing the exposure time of each of RGB in the display image, and sequentially displaying the image of the R component, the image of the G component, and the image of the B component on the image display device12in any order.

Exposure Time Optimization Method

FIG.12is a flowchart showing an example of a processing flow for optimizing an exposure time. Further,FIG.13shows an example of an evaluation system for spectral characteristics (brightness) used in optimizing an exposure time. In the evaluation system shown inFIG.13, a spectroradiometer “SR-3” manufactured by Topcon Technohouse Co., Ltd. is used as a spectroradiometer200, and the distance is 50 cm and the measurement angle is 2 degrees.

First, as a preprocessing step, in Step S100shown inFIG.12, an emission peak value of each of RGB of an ideal image display device is measured. An ideal image display device is an image display device that displays a display image that matches the tint of the recorded image recorded on the photosensitive recording medium14. The image display device is the image display device12in a state where the display image is optimized.

Specifically, an image of the R component, that is, an image of red (R) color having a pixel value of (255,0,0) is displayed on an ideal image display device, and an emission peak value is measured by the evaluation system shown inFIG.13. Similarly, an image of the G component, that is, an image of green (G) color having a pixel value of (0,255,0) is displayed on an ideal image display device, and an emission peak value is measured by the evaluation system shown inFIG.13. In addition, similarly, an image of the B component, that is, an image of blue (B) color having a pixel value of (0,0,255) is displayed on an ideal image display device, and an emission peak value is measured by the evaluation system shown inFIG.13. Thereby, the maximum value (maximum amount of light) of the optimum brightness in each of red (R), green (G), and blue (B) can be obtained.

Next, as a post-processing step, in Step S102shown inFIG.12, the emission peak value of each of RGB of the current image display device12before being incorporated into the image exposure device10is measured. As an example, in the present embodiment, the emission peak value of each of RGB in the image display device12before the louver film16is provided is measured. As for the measurement method, the image of the R component (255,0,0), the image of the G component (0,255,0), and the image of the B component (0,0,255) are sequentially displayed on the image display device12in the same manner as in Step S100described above, and the emission peak value in each image is measured by the spectroradiometer200. Thereby, the maximum value of the optimum brightness in the current image exposure device10in each of red (R), green (G), and blue (B), that is, the maximum amount of light can be obtained.

As a post-processing step at the end of exposure time optimization processing, in Step S104shown inFIG.12, the exposure time of the image of each RGB component is derived. The total amount of light that hits the photosensitive recording medium14in exposure is the amount obtained by multiplying each amount of light for each of RGB and the exposure time (light amount×exposure time). As an example, in the present embodiment, the amount of light exposed for 100 msec at the maximum value of the brightness in the ideal image display device measured in Step S100is defined as the total amount of light. That is, for each of RGB, the total amount of light for each of RGB is obtained by multiplying the maximum value (maximum amount of light) of the brightness measured in Step S100by 100 msec. Next, for each of RGB, the optimum exposure time of each of RGB is obtained by dividing each total amount of light by the maximum value of the brightness in the current image display device12measured in Step S102, that is, the maximum amount of light (total amount of light÷maximum amount of light). As an example, in the present embodiment, the optimum exposure time for each of the RGB thus obtained is stored in advance in the storage unit46of the image display device12.

The method of optimizing the exposure time for each of RGB is not limited to the above-mentioned method. For example, in a case where a white image (255, 255, 255) is displayed as a display image on the current image exposure device10and the photosensitive recording medium14is exposed by the present display image, the maximum value of the brightness of the display image for obtaining the optimum recorded image may be specified by adjusting the tint of the display image so that the recorded image is optimized.

Further, in the present embodiment, the color adjustment of each gradation was performed using a three-dimensional LookUp table (LUT) that refers to the combination of the output values of each of R, and B for the combination of the input values of each of R, and B.

Operation of Image Generation Unit30

Next, an operation of the image generation unit30of the image display device12of the present embodiment will be described.

As described above, the angle of the light radiated from the image display device12is limited by the louver film16, and the light parallel to the straight line connecting the image display device12and the photosensitive recording medium14passes through the light transmission parts102of the louver film16. However, in actual fact, as shown inFIG.14, light radiated from a point light source15of the display unit32is diffused. Specifically, according to the height H of the light shielding parts104and the width Q of the light transmission part102, a light component having a predetermined angle is transmitted, that is, diffused. Due to the diffused light component, as shown inFIG.15, in the recorded image recorded on the photosensitive recording medium14, a density difference of a high-frequency component (edge portion) E is reduced as compared with the display image. That is, in the recorded image, since the density difference is small, the edge portion tends to be difficult to be visually recognized, and as a result, there is a high concern that the recorded image may become a blurred image.

As the thickness t of the louver film16increases, the amount of light reaching the photosensitive recording medium14from the image display device12decreases, so that there is a problem in that the exposure time is extremely long. In addition, as in the example shown inFIG.8or9, in a case where the louver film16is formed of a plurality of layers, light is diffused in the directions not shielded by the light shielding parts104in each layer, and thus, blurring of the recorded image is likely to occur. Further, as the thickness of the protective layer17increases, the distance from the exposure surface14A of the photosensitive recording medium14increases, and the angle of light is not limited in the protective layer17, and thus, blurring of the recorded image is likely to occur.

Further, as described above, in the image exposure device10of the present embodiment, in a case where the controller31performs RGB sequential exposure at the optimized exposure time, the number of gradations of the display image does not decrease and the gradation skipping is reduced, so that the display image becomes a smooth image. However, by reducing the gradation skipping, the change in color shading is reduced, and as a result, the recorded image may become a blurred image. For example, as shown inFIG.16, in a case where the exposure time is optimized as compared with the case where gradation skipping occurs as described above, the recorded image has more gradations indicated by white circles in the graph. However, as shown inFIG.16, in the recorded image in which the exposure time is optimized, the image tends to be a blurred image with reduced visibility of the edge portion.

Therefore, in the present embodiment, the image generation unit30of the image display device12performs image processing to increase (emphasis) the high-frequency component (edge portion) of the display image in advance in consideration of the fact that the density difference is reduced in the recorded image rather than in the display image. In particular, the image generation unit30performs image processing for increasing (emphasizing) the high-frequency component (edge portion) of the display image in advance in consideration of the fact that the display image becomes the blurred image due to the optimization of the exposure time.

Image Processing

Next, image processing executed by the image display device12of the present embodiment will be described.FIG.17shows a flowchart of an example of image processing executed by the image display device12of the present embodiment. The image processing shown inFIG.17is executed in a case where the CPU40executes the image processing program50.

In Step S150shown inFIG.17, the image generation unit30performs, on the input image data, high-frequency component emphasis processing for emphasizing the density difference of the high-frequency component of the input image. In the present embodiment, the image generation unit30performs unsharp masking as an example of the high-frequency component emphasis processing.

Specifically, first, an unsharp mask is generated. For the generation of the unsharp mask, for example, a two-dimensional Gaussian distribution is applied, in which f(x, y) is a filter coefficient and the degree of distribution is a standard deviation σ, as shown in the following expression (1).

f⁡(x,y)=12⁢⁢πσ2⁢e-x2+y22⁢σ2(1)

The standard deviation σ in the above expression (1) is a Gaussian distribution, that is, the radius of blurring of a blurred image, and is denoted by the number of pixels in the present embodiment.

By multiplying the input image by the unsharp mask shown in the expression (1), the blurred image is generated from the input image as shown inFIG.18A.

Further, as shown inFIG.18B, the image generation unit30generates a high-frequency component image from a difference between the input image and the blurred image. As shown inFIG.18B, in the high-frequency component image, the difference becomes particularly large in the region where a gradation difference is large.

Furthermore, as shown inFIG.18C, the image generation unit30adds the high-frequency component image to the input image according to a weight W to generate a display image in which the high-frequency component is emphasized. That is, the display image is in a state in which the image quality is deteriorated as compared with the input image.

In a case where the resolution of the image display device12is 325 ppi (pixel per inch), in the unsharp masking to be applied to the input image, the range of the unsharp mask to be applied is preferably a range M1represented by the following expression (2), more preferably a range M2represented by the following expression (3), and still more preferably a range M3represented by the following expression (4) in a case where the standard deviation σ is denoted by x and the weight W is denoted by y, as shown inFIG.19.
−0.1×x+0.40<y<−0.1×x+1.10  (2)
−0.1×x+0.50<y<−0.1×x+1.00  (3)
−0.1×x+0.60<y<−0.1×x+0.90  (4)

In a case where the resolution of the image display device12is X ppi, an unsharp mask corresponding to a range obtained by multiplying the standard deviation σ of the above expressions (2) to (4) by the number obtained by dividing X by 325 may be applied. Specifically, an unsharp mask corresponding to the ranges M1to M3represented by each of the following expressions (5) to (7) may be applied.
−0.1×x×(X÷325)+0.40<y<−0.1×x×(X÷325)+1.10  (5)
−0.1×x×(X÷325)+0.50<y<−0.1×x×(X÷325)+1.00  (6)
−0.1×x×(X÷325)+0.60<y<−0.1×x×(X÷325)+0.90  (7)

In the next Step S152, the controller31generates an image of the R component, an image of the G component, and an image of the B component from the display image to which high-frequency component emphasis processing has been performed by the processing of Step S150. As an example, in the image processing using NumPy of the Python language, the controller31of the present embodiment separates the color channels of the display image to generate an image (single color image) of each RGB component. The method by which the controller31generates an image of each RGB component from the display image is not limited to this method, and a known technique can be applied.

In the next Step S154, the controller31acquires the optimum exposure time for each of RGB from the storage unit46. In the next Step S156, as shown inFIG.20, the controller31performs sequential exposure to display each of the image of the R component, the image of the G component, and the image of the B component according to the optimum exposure time such that the display image is displayed on the display unit32. In the example shown inFIG.20, the controller31displays (turns on) the image of the B component on the display unit32at an exposure start time T0, and hides (turns off) the image of the B component at a time T1. Specifically, the controller31turns on the sub-pixel13B of the pixel13during the time T0to T1and exposes the photosensitive recording medium14with the B-color display image. Further, the controller31switches the image to be displayed on the display unit32from the image of the B component to the image of the G component during the period from the time T1to a time T2, displays (turns on) the image of the G component on the display unit32at the time T2, and hides (turns off) the image of the G component at a time T3. Specifically, the controller31turns on the sub-pixel13G of the pixel13during the time T2to T3and exposes the photosensitive recording medium14with the G-color display image. Further, the controller31switches the image to be displayed on the display unit32from the image of the G component to the image of the R component during the period from the time T3to a time T4, displays (turns on) the image of the R component on the display unit32at the time T4, and hides (turns off) the image of the R component at a time T5. Specifically, the controller31turns on the sub-pixel13R of the pixel13during the time T4to T5and exposes the photosensitive recording medium14with the R-color display image. In a case where the RGB sequential exposure by the controller31in Step S156is terminated, the present image processing is ended, and a recorded image having an optimized tint is recorded on the photosensitive recording medium14.

Effect Experiment of Image Exposure Device

Next, an experimental result performed on the effect of the image exposure device10of the present embodiment will be shown.

In the experiment, a general display having a resolution of 271 ppi was used as the image display device12. In addition, the support portion21was a metal plate, and as the photosensitive recording medium14, an Instax film was used. Further, as the louver film16, the louver film in which the first layer118, in which light transmission parts102having a thickness of 45 μm and light shielding parts104having a thickness of 15 μm were alternately disposed only in the first direction, and the second layer119, in which light transmission parts102having a thickness of 45 μm and light shielding parts104having a thickness of 15 μm were alternately disposed only in the second direction perpendicular to the first direction, were laminated was used. The thickness of each layer of the louver film16was set to 1.15 mm (thickness t=2.3 mm). In addition, the thickness of the protective layer17on each surface was set to 0.2 and the louver film16was rotated by 30 deg with respect to a pixel disposition (XY axes) of the display unit32.

As the display image, a general photographic image in which a landscape or a person was a subject was used. In addition, an image in which the high-frequency component was not emphasized (the edge portion is emphasized) was used as a comparison image for the recorded image of the present embodiment. Hereinafter, a recorded image to which a high-frequency emphasized image of the present embodiment is applied may be referred to as an “emphasized image” in order to distinguish the recorded image from the comparison image.

Further, in the high-frequency component emphasis (edge emphasis) processing, the unsharp masking using the two-dimensional Gaussian distribution shown in (1) described above was performed by making the standard deviation σ and the weight W different as shown inFIG.21. Further, the exposure time of the image of each RGB component in the RGB sequential exposure was set to the optimum exposure time obtained by the above-mentioned exposure time optimization method, and the image of the G component, the image of the R component, and the image of the B component were sequentially exposed in this order.

An evaluation method of an image quality was a sensory evaluation by an evaluation expert who has evaluated a sense of resolution of the photograph as to whether or not blurred feeling of the emphasized image is less than the comparison image, has good visibility, and is a preferable image.

FIG.21shows the evaluation result. InFIG.21, the image quality was evaluated in four stages. InFIG.21, “A” represents that the visibility is best, “B” represents that the visibility is good, “C” represents that the blurring of the image is improved, and “D” represents that the visibility is poor, in other words, the image is blurred.

Therefore, as shown inFIG.21, and as described above, it can be seen that the range of the unsharp mask is preferably the range M1represented by the above-described expression (2) where the standard deviation σ is denoted by x and the weight W is denoted by y, the range M2represented by the above-described expression (3) is more preferable, and the range M3represented by the above-described expression (4) is more preferable.

Second Embodiment

In the first embodiment, a method of performing RGB sequential exposure has been described as a method of exposing the photosensitive recording medium14by the image display device12. In the present embodiment, as another method in which the image display device12exposes the photosensitive recording medium14, a method in which the image display device12(image exposure device10) can collectively expose the image of the R component, the image of the G component, and the image of the B component at the same time will be described.

Since the overall configuration of the image exposure device10, and the configuration of the support portion21, the photosensitive recording medium14, and the louver film16are the same as those in the first embodiment, the description thereof will be omitted.

Image Display Device

In the present embodiment, the hardware configuration of the image display device12is the same as that of the first embodiment (seeFIG.5), but since the functional configuration thereof is different, the functional configuration and operation of the image display device12will be described.

FIG.22is a block diagram showing an example of a functional configuration of the image display device12of the present embodiment. The image display device12of the present embodiment is different from the image display device12of the first embodiment (seeFIG.4) in that it further comprises a reception unit34.

The image display device12of the present embodiment has two modes, as a mode for exposing the photosensitive recording medium14, a sequential exposure mode in which RGB sequential exposure is performed, and as shown inFIG.23, a batch exposure mode for performing batch exposure in which an image of an R component, an image of a G component, and an image of a B component are exposed at the same time.

In a case where the sequential exposure mode is performed, as described above, the tint of the recorded image recorded on the photosensitive recording medium14can be set to a desired tint, and it is possible to suppress the occurrence of gradation skipping in the recorded image recorded on the photosensitive recording medium14. Therefore, in a case where the sequential exposure mode is performed, the image quality of the recorded image can be further improved.

On the other hand, in the batch exposure mode, as an example of a method of adjusting the tint of the display image in the image display device12in order to make the tint of the recorded image recorded on the photosensitive recording medium14a desired tint, the above-mentioned method of changing a gradation assignment value of each color of RGB is employed. Therefore, as described above, gradation skipping may occur in the recorded image recorded on the photosensitive recording medium14. Therefore, the image quality of the recorded image may be lower than that in the case of performing RGB sequential exposure.

However, in the sequential exposure mode, since the image of the R component, the image of the G component, and the image of the B component are sequentially exposed, until the exposure of the images of all the RGB components is completed, in other words, the exposure time until the exposure of the photosensitive recording medium14is completed becomes long. On the other hand, in the RGB batch exposure, as shown inFIG.23, since the image of the R component, the image of the G component, and the image of the B component are exposed at the same time, the exposure times overlap, and the time required to complete the exposure of the photosensitive recording medium14becomes shorter than that in the case of performing RGB sequential exposure. Therefore, in the case of performing RGB batch exposure, power consumption can be suppressed as compared with the case of performing RGB sequential exposure.

In other words, the sequential exposure mode is an image quality-oriented (high image quality) mode, and the batch exposure mode is an energy-saving mode that suppresses power consumption.

As an example, the reception unit34of the image display device12of the present embodiment receives an instruction given by the user as to whether to perform the sequential exposure mode or the batch exposure mode via an external interface (I/F) (not shown).

In a case where the reception unit34receives the instruction of the sequential exposure mode, the image generation unit30generates a display image to which the high-frequency component emphasis processing is performed as in the first embodiment. On the other hand, in a case where the reception unit34receives the instruction of the batch exposure mode, the image generation unit30generates a display image that has undergone high-frequency component emphasis processing in which the degree of emphasizing the density difference (edge) of high-frequency components is weaker than that of RGB sequential exposure. Even in the case of RGB batch exposure, as described above, the light radiated from the point light source15of the display unit32is diffused (seeFIGS.14and15), so that there is a concern that the image may be blurred. Therefore, the image generation unit30performs, on the input image data, high-frequency component emphasis processing for emphasizing the density difference of the high-frequency component of the input image.

On the other hand, as described above, in a case where RGB sequential exposure is performed by optimizing the exposure time, as a result of the light radiated from the point light source15of the display unit32being diffused, and gradation skipping being suppressed, the image tends to be a blurred image with reduced visibility of the edge portion. Therefore, in the RGB sequential exposure, the image generation unit30performs high-frequency component emphasis processing on the input image by further emphasizing the edge portion, that is, the density difference. In other words, in the case of RGB sequential exposure, the image generation unit30performs high-frequency component emphasis processing in which the density difference (edge) of the high-frequency component is emphasized more than in the RGB batch exposure.

In a case where the reception unit34receives the instruction of the sequential exposure mode, the controller31performs RGB sequential exposure and causes the photosensitive recording medium14to record the recorded image, as in the first embodiment. On the other hand, in a case where the reception unit34receives the instruction of the batch exposure mode, the controller31performs RGB batch exposure and causes the photosensitive recording medium14to record the recorded image, as shown inFIG.23.

Image Processing

Next, image processing executed by the image display device12of the present embodiment will be described.FIG.24shows a flowchart of an example of image processing executed by the image display device12of the present embodiment. The image processing shown inFIG.24is different from the image processing of the first embodiment (seeFIG.17) in that the processing of steps S149, S158, and S160is further provided.

In a case where the image processing shown inFIG.24starts, first, in Step S149, the reception unit34determines whether or not the instruction of the received mode is the sequential exposure mode. In a case where the instruction of the sequential exposure mode is received, the determination in Step S149is a positive determination, and the processing proceeds to Step S150. On the other hand, in a case where the instruction of the received mode is not the sequential exposure mode, in other words, in a case where the instruction of the batch exposure mode is received, the determination in Step S149is a negative determination, and the processing proceeds to Step S158.

In Step S158, the image generation unit30performs, on the input image data, high-frequency component emphasis processing for emphasizing the density difference of the high-frequency component of the input image. As an example, in the present embodiment, similarly to Step S150, the image generation unit30performs high-frequency component emphasis processing by performing unsharp masking using the unsharp mask generated by the above expression (1).

In a case where the resolution of the image display device12is 325 ppi (pixel per inch), in the unsharp masking to be applied to the input image, the range of the unsharp mask to be applied is preferably a range M1represented by the following expression (8), more preferably a range M2represented by the following expression (9), and still more preferably a range M3represented by the following expression (10) in a case where the standard deviation σ is denoted by x and the weight W is denoted by y, as shown inFIG.25.
−0.1×x+0.30<y<−0.1×x+1.00  (8)
−0.1×x+0.40<y<−0.1×x+0.90  (9)
−0.1×x+0.50<y<−0.1×x+0.80  (10)

In a case where the resolution of the image display device12is X ppi, an unsharp mask corresponding to a range obtained by multiplying the standard deviation σ of the above expressions (8) to (10) by the number obtained by dividing X by 325 may be applied. Specifically, an unsharp mask corresponding to the ranges M1to M3represented by each of the following expressions (11) to (13) may be applied.
−0.1×x×(X÷325)+0.30<y<−0.1×x×(X÷325)+1.00  (11)
−0.1×x×(X÷325)+0.40<y<−0.1×x×(X÷325)+0.90  (12)
−0.1×x×(X÷325)+0.50<y<−0.1×x×(X÷325)+0.80  (13)

In the next Step S160, the controller31causes the display unit32to display the display image to which the high-frequency component emphasis processing has been performed by the processing of the above Step S158by RGB batch exposure. Specifically, as shown inFIG.23, the controller31displays (turns on) the image of the R component, the image of the G component, and the image of the B component on the display unit32all at once at an exposure start time T0, and hides (turns off) the image of the R component, the image of the G component, and the image of the B component all at once at a time TX at which the predetermined exposure time is reached. In a case where the photosensitive recording medium14is exposed and the recorded image is recorded, the process of Step S160is terminated, and the present image processing is ended.

As described above, the image exposure device10of each of the above embodiments comprises an image display device12having a plurality of pixels13, a support portion21that supports a photosensitive recording medium14for recording an image displayed on the image display device12in a state in which an exposure surface14A of the photosensitive recording medium14faces the image display device12, and a louver film16that is provided between the image display device12and the support portion21and limits an angle of light radiated from the image display device12to the photosensitive recording medium14. Further, the image exposure device10comprises an image generation unit30that generates a display image in which an image quality of a color input image represented by input image data is deteriorated by emphasizing a density difference of a high-frequency component of the input image, and a controller31that performs a control for generating an image of an R component, an image of a G component, and an image of a B component from the display image and sequentially displaying each of the image of the R component, the image of the G component, and the image of the B component on the image display device12in a predetermined order to sequentially expose the photosensitive recording medium14.

As described above, the controller31of the image display device12in the image exposure device10of each of the above embodiments sequentially displays each of the image of the R component, the image of the G component, and the image of the B component on the image display device12in a predetermined order to sequentially expose the photosensitive recording medium14. Thereby, the exposure time of each of the image of the R component, the image of the G component, and the image of the B component can be optimized, and the gradation skipping of the recorded image recorded on the photosensitive recording medium14can be suppressed. Further, the image generation unit30of the image display device12of each of the above embodiments generates a display image to be used for the exposure of the photosensitive recording medium14by emphasizing a density difference of a high-frequency component of a color input image represented by input image data as an image in which the image quality of the input image is deteriorated. The recorded image recorded on the photosensitive recording medium14becomes a blurred image than the display image due to the diffusion of the light transmitted through the louver film16, but the image has the same image quality as the input image. That is, according to the image exposure device10of the present embodiment, even in a case where the image quality of the display image is deteriorated, the image quality of the recorded image is the same as the image quality of the input image.

Therefore, according to the image exposure device10of each of the above embodiments, it is possible to suppress blurring of the recorded image and suppress gradation skipping.

In each of the above embodiments, a mode in which each of the plurality of pixels13of the image display device12comprises sub-pixels13R,13G and13B to display a color image on the image display device12has been described, but the configuration of the image display device12for displaying the color image is not limited to this mode. For example, the image display device12may be provided with a light source or a filter corresponding to each of the R component, the G component, and the B component.

In each of the above embodiments, the aspect in which the unsharp masking is performed as the high-frequency component emphasis processing performed by the image generation unit30has been described, but the present disclosure is not limited to the present embodiment, and for example, convolution processing or the like may be applied.

For example, the structure of the louver film16is also not limited, and further, it is not limited as long as it is a limiting member capable of limiting the angle of the light radiated from the image display device12. For example, the light transmission parts102and the light shielding parts104may be disposed aperiodically, and a capillary plate or the like in which holes are randomly formed may be used as the limiting member.

In addition, in each of the above embodiments, the aspect in which the image display device12comprises the image generation unit30and the controller31has been described, but each of the image generation unit30and the controller31may be configured as a device different from the image display device12. For example, a CPU such as a smartphone may execute the image processing program50to perform image processing by functioning as the image generation unit30and the controller31and the image display device12may receive the image data subjected to the image processing from the smartphone and display a display image corresponding to the image data on the display unit32. Further, the image generation unit30and the controller31may be provided in different devices.

Further, as hardware structures of processing units that execute various kinds of processing such as each functional unit of the image display device12in each of the above embodiments, various processors shown below can be used. As described above, the various processors include a programmable logic device (PLD) as a processor of which the circuit configuration can be changed after manufacture, such as a field programmable gate array (FPGA), a dedicated electrical circuit as a processor having a dedicated circuit configuration for executing specific processing such as an application specific integrated circuit (ASIC), and the like, in addition to the CPU as a general-purpose processor that functions as various processing units by executing software (program).

One processing unit may be configured by one of the various processors, or configured by a combination of the same or different kinds of two or more processors (for example, a combination of a plurality of FPGAs or a combination of the CPU and the FPGA). In addition, a plurality of processing units may be configured by one processor.

As an example where a plurality of processing units are configured by one processor, first, there is a form in which one processor is configured by a combination of one or more CPUs and software as typified by a computer, such as a client or a server, and this processor functions as a plurality of processing units. Second, as represented by a system on chip (SoC) or the like, there is a form of using a processor for realizing the function of the entire system including a plurality of processing units with one integrated circuit (IC) chip. In this way, various processing units are configured by one or more of the above-described various processors as hardware structures.

Furthermore, as the hardware structure of the various processors, more specifically, an electrical circuit (circuitry) in which circuit elements such as semiconductor elements are combined can be used.

In the above embodiment, the image processing program50is described as being stored (installed) in the storage unit46in advance; however, the present disclosure is not limited thereto. The image processing program50may be provided in a form recorded in a recording medium such as a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), and a universal serial bus (USB) memory. In addition, the image processing program50may be downloaded from an external device via a network.

The disclosure of Japanese Patent Application No. 2019-177694 filed Sep. 27, 2019 is incorporated herein by reference in its entirety.

All literatures, patent applications, and technical standards described herein are incorporated by reference to the same extent as if the individual literature, patent applications, and technical standards were specifically and individually stated to be incorporated by reference.