Patent Description:
Image generation devices that include an imaging element with multiple pixels have been known. As an example of this type of image generation devices, non-patent literature <NUM> describes an image generation device that includes a color filter and an imaging element. In this image generation device, each pixel in the imaging element includes four subpixels. The color filter in this image generation device splits incident light into R (red), G (green), B (blue), and IR (infrared) components, each of which is then photoelectrically converted in corresponding subpixels. Image processing is then performed to generate a color image.

In the image generation device in non-patent literature <NUM>, however, the use of the color filter necessitates each pixel to include four subpixels of R, G, B, and IR. This increases the area per pixel, posing the problem of a decreased resolution of color images.

According to one aspect of the embodiments of the present invention, there is provided an image generation device capable of increasing the resolution of color images. According to another aspect of the embodiments of the present invention there is provided an image generation method capable of increasing the resolution of color images. Additional benefits and advantages of aspects of the embodiments of the present invention will become apparent from this specification and the drawings.

An image generation device according to the embodiments of the present invention as claimed in appended claim <NUM>.

An image generation method according to the embodiments of the present invention as claimed in appended claim <NUM>.

The embodiments of the present invention may be implemented using a system, a computer program, or a computer-readable recording medium, or may be implemented using a combination of a device, a system, a method, a computer program, and a computer-readable recording medium. The computer-readable recording medium may be a nonvolatile recording medium such as, for example, a CD-ROM (Compact Disc-Read Only Memory).

According to the present disclosure, the resolution of color images can be increased.

In conventional image generation devices that use a color filter, each pixel needs to include four subpixels of R, G, B, and IR. This increases the area per pixel, posing the problem of a decreased resolution of color images. In order to solve this problem, a device is proposed that generates a color image of an object without using a color filter for imaging the object. If an object can be imaged without using a color filter, the area per pixel can replace the area per subpixel of the conventional art to reduce the area per pixel. Consequently, the resolution of color images can be increased.

<FIG> is a schematic diagram showing image capturer <NUM> and voltage generator <NUM> in an image generation device.

Image capturer <NUM> includes imaging element <NUM> having multiple pixels. Imaging element <NUM> includes: FDs (floating diffusions) <NUM> provided on silicon substrate <NUM>; metal wires and pixel electrodes electrically connected to FDs <NUM>; organic photoconductive film OPF provided on the pixel electrodes; and transparent electrode <NUM> provided on organic photoconductive film OPF.

Organic photoconductive film OPF is a light guide film that photoelectrically converts light entering through transparent electrode <NUM>. Organic photoconductive film OPF has a stacked structure including a layer for detecting visible light and a layer for detecting near-infrared light. Electric charge resulting from photoelectric conversion by organic photoconductive film OPF is stored in FDs <NUM>.

Voltage generator <NUM> for applying voltage to organic photoconductive film OPF via transparent electrode <NUM> is connected to image capturer <NUM>.

<FIG> is a schematic diagram showing an example of wavelength-sensitivity characteristics of imaging element <NUM> having organic photoconductive film OPF.

As shown, imaging element <NUM> exhibits different sensitivity characteristic tendencies for each of voltages H and L (L < H) applied to organic photoconductive film OPF. Specifically, between the applied voltages H and L, the sensitivity for blue, green, and red wavelengths appears to differ not by a fixed factor but by a variable factor.

Thus, the sensitivity characteristic of imaging element <NUM> having organic photoconductive film OPF depends on the voltage applied to organic photoconductive film OPF. As such, the present disclosure proposes a device in which different sensitivity characteristics (filter characteristics) are created by varying the voltage applied to an organic photoconductive film, and based on data obtained from these sensitivity characteristics, a color image is generated. An image generation device and other features of the present disclosure will be described below.

An image generation device according to an aspect of the present disclosure includes: a voltage generator that generates a plurality of voltages each having a different voltage value; an image capturer that includes an organic photoconductive film, and performs imaging every time each of the plurality of voltages is applied; a luminance data obtainer that obtains a plurality of luminance data items corresponding to the plurality of voltages applied, each of the plurality of luminance data items being obtained from the imaging performed by the image capturer; and a color image generator that generates a color image based on the plurality of luminance data items.

As above, multiple sensitivity characteristics can be created by applying multiple voltages to the organic photoconductive film. Based on multiple luminance data items obtained from these sensitivity characteristics, a color image can be generated. Consequently, the color image can be generated without using a color filter and therefore with a small area per pixel. This can increase the resolution of the color image.

Moreover, the color image generator may generate the color image by multiplying the plurality of luminance data items by a set of coefficients that is predetermined.

In the above manner, a color image can be generated in a simple manner based on the multiple luminance data items. According to the image generation device of the present disclosure, the resolution of the color image generated in the above simple manner can be increased.

Moreover, the set of coefficients may be derived by: imaging a color chart having a plurality of colors using the image capturer to obtain a determinant including color data corresponding to the plurality of colors, the set of coefficients, and the plurality of luminance data items; and solving the determinant using a pseudo inverse matrix.

In the above manner, a closely reproduced color image can be generated based on the multiple luminance data items. According to the image generation device of the present disclosure, the resolution of the closely reproduced color image generated as above can be increased.

Moreover, the set of coefficients may be derived by: imaging a color chart having a plurality of colors using the image capturer; and performing learning using, as input data, the plurality of luminance data items obtained from the imaging of the color chart, and as label data, color data corresponding to the plurality of colors.

Moreover, the voltage generator may change at least one of the plurality of voltages in accordance with a scene in which the imaging is performed by the image capturer.

As above, imaging for various purposes is possible by changing the voltage according to the scene in which the imaging is performed. According to the image generation device of the present disclosure, the resolution of color images generated by imaging for various purposes can be increased.

Moreover, the voltage generator may modulate at least one of the plurality of voltages during exposure by the image capturer.

As above, modulating the voltage during exposure enables a sensitivity characteristic for a specific purpose to be created and then used to generate a color image. According to the image generation device of the present disclosure, the resolution of color images generated by imaging for various purposes can be increased.

Moreover, the image capturer includes a plurality of organic photoconductive films that are stacked, each of the plurality of organic photoconductive films being the organic photoconductive film, and a total number of the plurality of voltages to be applied to the plurality of organic photoconductive films may be greater than or equal to a total number of the plurality of organic photoconductive films.

In the above manner, more sensitivity characteristics can be created. This enables a closely reproduced color image to be generated using further accurate sensitivity characteristics.

Moreover, the image capturer includes, as the plurality of organic photoconductive films, a first organic photoconductive film for detecting visible light and a second organic photoconductive film for detecting near-infrared light, and the first organic photoconductive film may be disposed closer to an object than the second organic photoconductive film is.

In the above manner, the first organic photoconductive film can detect near-infrared light after the second organic photoconductive film detects and eliminates visible light. This can improve near-infrared light detection performance.

Moreover, the image capturer includes, as the plurality of organic photoconductive films, a first organic photoconductive film for detecting visible light and a second organic photoconductive film for detecting near-infrared light, and the second organic photoconductive film may be disposed closer to an object than the first organic photoconductive film is.

In the above manner, the second organic photoconductive film can detect visible light after the first organic photoconductive film detects and eliminates near-infrared light. This can improve color reproducibility for visible light.

Moreover, an image generation method according to an aspect of the present disclosure includes: performing imaging by applying, to an organic photoconductive film, a plurality of voltages each having a different voltage value; obtaining a plurality of luminance data items corresponding to the plurality of voltages applied, the plurality of luminance data items being obtained from the imaging; and generating a color image based on the plurality of luminance data items.

These general or specific aspects include one or more combinations of a device, a system, a method, an integrated circuit, a computer program, and a computer-readable recording medium.

Embodiments will be described in detail below with reference to the drawings. Any of the embodiments to be described below illustrates an example of the present invention. Values, shapes, materials, elements, arrangements and connections of elements, steps, and the order of steps illustrated in the following embodiments are exemplary and not intended to limit the present invention. Among the elements in the following embodiments, those not set forth in the independent claims representing implementations according to aspects of the present invention will be described as optional elements. Implementations of the present invention are not limited to the current independent claims but may also be represented by other independent claims.

The drawings are schematic views and not necessarily drawn to scale. Throughout the drawings, substantially like components are given like symbols, and redundant description thereof may be omitted or simplified.

Configurations of an image generation device in embodiment <NUM> will be described with reference to <FIG>.

<FIG> is a schematic diagram showing image generation device <NUM> in embodiment <NUM>. <FIG> is a block diagram showing a configuration of image generation device <NUM>.

As shown in <FIG>, image generation device <NUM> includes: image capturer <NUM> that images an object Ob1; voltage generator <NUM> that generates voltages to be applied to image capturer <NUM>; and data processor <NUM> that processes an imaging result obtained by image capturer <NUM>.

Data processor <NUM> includes: luminance data obtainer <NUM> that obtains luminance data from the imaging result obtained by image capturer <NUM>; and color image generator <NUM> that generates a color image based on the luminance data.

In <FIG>, voltage generator <NUM> is separate from data processor <NUM> and image capturer <NUM>. Alternatively, voltage generator <NUM> may be provided in the housing containing data processor <NUM> or in the housing containing image capturer <NUM>.

This embodiment may also be implemented as an image generation system that includes: a signal generation device having image capturer <NUM> and voltage generator <NUM>; and a data processing device corresponding to data processor <NUM>. In this case, the signal generation device and the data processing device each have a communicator. The signal generation device transmits digital signals (to be described below) to the data processing device through wired or wireless communication.

<FIG> is a schematic diagram showing image capturer <NUM> and voltage generator <NUM> in image generation device <NUM>.

Image capturer <NUM> includes: microlenses <NUM>; and imaging element <NUM> having pixels arranged in an array. In this embodiment, no color filter is provided between microlenses <NUM> and imaging element <NUM>.

Microlenses <NUM> are arranged in an array in correspondence with the respective pixels. Each microlens <NUM> gathers incident light and directs the light toward the corresponding pixel in imaging element <NUM>.

Imaging element <NUM> is an element that receives light gathered by microlenses <NUM> and outputs electric signals. Imaging element <NUM> includes: silicon substrate <NUM>; FDs <NUM> provided on silicon substrate <NUM>; metal wires <NUM> and pixel electrodes <NUM> electrically connected to FDs <NUM>; organic photoconductive film <NUM> provided on pixel electrodes <NUM>; and transparent electrode <NUM> provided on organic photoconductive film <NUM>.

Transparent electrode <NUM> is a light-transmissive electrode and is formed of a transparent material such as ITO (Indium Tin Oxide) or ZnO. Transparent electrode <NUM> is disposed between microlenses <NUM> and organic photoconductive film <NUM>, and connected to voltage generator <NUM> via, e.g., wiring.

Organic photoconductive film <NUM> is a light guide film that photoelectrically converts light entering through microlenses <NUM> and transparent electrode <NUM>. As described above, imaging element <NUM> having organic photoconductive film <NUM> has a characteristic such that the light sensitivity depends on the value of voltage applied to organic photoconductive film <NUM>. Although organic photoconductive film <NUM> shown in <FIG> is single-layered, this is not restrictive. Rather, organic photoconductive film <NUM> may include multiple layers, such as a layer for detecting the R component, a layer for detecting the G component, and a layer for detecting the B component. Organic photoconductive film <NUM> is connected to FDs <NUM> via pixel electrodes <NUM> and metal wires <NUM>.

Each FD <NUM> is a charge storage node that stores electric charge resulting from photoelectric conversion performed by organic photoconductive film <NUM>. Imaging element <NUM> has multiple FDs <NUM>, which are disposed in one-to-one correspondence with the pixels. FDs <NUM> store the electric charge during imaging, i.e., exposure, performed by image capturer <NUM>.

Voltage generator <NUM> is a voltage generation device that generates multiple voltages of different voltage values. For example, voltage generator <NUM> has multiple transistors and generates multiple voltages by turning on and off the transistors. Voltage generator <NUM> has its positive side connected to transparent electrode <NUM>, and its negative side grounded. Voltage generator <NUM> applies the voltages to organic photoconductive film <NUM> via transparent electrode <NUM>.

<FIG> is a diagram showing an example of data obtained by image generation device <NUM>.

In this embodiment, the object Ob1 is imaged while voltage generator <NUM> is used to vary the voltage applied to organic photoconductive film <NUM>. For example, in image generation device <NUM>, three voltages V1, V2, and V3 are sequentially applied to organic photoconductive film <NUM> to create three different sensitivity characteristics. Image capturer <NUM> performs imaging when each of the three voltages V1 to V3 is applied.

Electric charge obtained by organic photoconductive film <NUM> having the three characteristics is stored in FDs <NUM> for each imaging time. Image capturer <NUM> detects potentials resulting from the electric charge stored in FDs <NUM> and converts the potentials into digital signals, which are output to data processor <NUM>. Voltage generator <NUM> may transmit information on the voltages applied (the magnitudes of the voltages applied, and the application times) to data processor <NUM>.

Luminance data obtainer <NUM> obtains luminance data based on the digital signals output from image capturer <NUM>. Specifically, as shown in <FIG>, luminance data obtainer <NUM> obtains luminance data D1, D2, and D3 corresponding to the respective voltages V1 to V3 applied by image capturer <NUM> in imaging the object Ob1.

Color image generator <NUM> generates a color image Dc based on the luminance data D1 to D3. Specifically, color image generator <NUM> multiplies the luminance data D1 to D3 by a predetermined set of coefficients A1 (see Formula (<NUM>)) and performs data processing, thereby generating the color image Dc. It is to be noted that color image generator <NUM> may generate the color image Dc using information on the voltages actually applied, or using information on the predetermined voltages to be applied. That is, the color image Dc may be generated using a set of coefficients corresponding to the voltage values. Color image generator <NUM> outputs the generated color image Dc as a digital signal or an analog signal to the outside of image generation device <NUM> via, e.g., a video output terminal (not shown).

Now, an image generation method in this embodiment will be described with reference to <FIG>. The description here is mainly directed to an example in which three voltages V1 to V3 are applied to organic photoconductive film <NUM>.

<FIG> is a flowchart showing the image generation method in embodiment <NUM>.

First, the object Ob1 is imaged while the voltages V1 to V3 are applied to organic photoconductive film <NUM> (M10). Image generation device <NUM> obtains the luminance data D1 to D3 resulting from the imaging by image capturer <NUM> and corresponding to the respective voltages V1 to V3 applied (M20). Details of operations in M10 and M20 are as follows.

First, image capturer <NUM> images the object Ob1 while voltage V1 is applied to organic photoconductive film <NUM> (M11). Image capturer <NUM> converts the potential created by the imaging in FDs <NUM> into a digital signal and outputs the digital signal. Luminance data obtainer <NUM> obtains luminance data D1 based on the digital signal output from image capturer <NUM> (M21). After the data is obtained, the electric charge stored in FDs <NUM> is released.

Image capturer <NUM> then images the object Ob1 while voltage V2 (for example, V2 > V1) is applied to organic photoconductive film <NUM> (M12). Image capturer <NUM> converts the potential created by the imaging in FDs <NUM> into a digital signal and outputs the digital signal. Luminance data obtainer <NUM> obtains luminance data D2 based on the digital signal output from image capturer <NUM> (M22). After the data is obtained, the electric charge stored in FDs <NUM> is released.

Image capturer <NUM> then images the object Ob1 while voltage V3 (for example, V3 > V2) is applied to organic photoconductive film <NUM> (M13). Image capturer <NUM> outputs the potential created by the imaging in FDs <NUM> into a digital signal and outputs the digital signal. Luminance data obtainer <NUM> obtains the luminance data D3 based on the digital signal output from image capturer <NUM> (M23). After the data is obtained, the electric charge stored in FDs <NUM> is released.

By performing the above operations (M10 and M20), image generation device <NUM> obtains the three luminance data items D1 to D3.

Color image generator <NUM> then generates a color image based on the three luminance data items D1 to D3 (M30). Specifically, color image generator <NUM> generates the color image Dc by multiplying the three luminance data items D1 to D3 by a predetermined set of coefficients A1.

Here, a manner of generating the color image Dc from the luminance data D1 to D3 will be described in detail. While the luminance data D1 to D3 and the color image Dc shown in <FIG> represent data on all the pixels imaged, the description here will initially focus on one of the pixels for ease of understanding.

For one pixel being focused on, the three luminance data items obtained by the imaging are expressed as luminance data (i<NUM>, i<NUM>, i<NUM>), for example. The color image (r<NUM>, g<NUM>, b<NUM>) generated includes R, G, and B components and is expressed by (Equation <NUM>) below. The set of coefficients A1 is expressed by a transformation matrix of (Equation <NUM>). <NUM>] <MAT>
[Math. <NUM>] <MAT>.

Cr1, Cg1, Cb1 in the set of coefficients A1 are characteristic values appearing when voltage V1 is applied to organic photoconductive film <NUM>. Cr2, Cg2, Cb2 are characteristic values appearing when voltage V2 is applied to organic photoconductive film <NUM>. Cr3, Cg3, Cb3 are characteristic values appearing when voltage V3 is applied to organic photoconductive film <NUM>.

Based on the above, a case will be described in which p is the total number pixels (p is an integer greater than <NUM>) and N is the number of different voltages applied to organic photoconductive film <NUM> (N is an integer greater than <NUM>). Luminance data D1 to DN obtained by the imaging is then expressed as luminance data (i<NUM>,<NUM> to ip,N). The color image (r<NUM>,g<NUM>,b<NUM> to rp,gp,bp) generated includes R, G, and B components and is expressed by (Equation <NUM>) below. A set of coefficients A is expressed by a transformation matrix of (Equation <NUM>). <NUM>] <MAT>
[Math. <NUM>] <MAT>.

Cr1, Cg1, Cb1 in the set of coefficients A are characteristic values appearing when voltage V1 is applied to organic photoconductive film <NUM>. CrN, CgN, CbN are characteristic values appearing when the N-th voltage VN is applied to organic photoconductive film <NUM>.

As above, if imaging is performed while the N voltages V1 to VN are applied to organic photoconductive film <NUM>, the luminance data D1 to DN obtained by the imaging can be multiplied by the above set of coefficients A to generate the color image Dc.

Here, a manner of deriving the set of coefficients A used in the above image generation method will be described.

<FIG> is a diagram showing an example of the manner of obtaining the set of coefficients A used in the image generation method. <FIG> shows a color chart Ob2 of multiple colors, and a standard light source. The color chart Ob2 used in this embodiment is the Macbeth chart and has <NUM> colors. The color chart Ob2 is not limited to the Macbeth chart but may be any sample object in which color data corresponding to each color is known.

First, the color chart Ob2 is imaged with image capturer <NUM>. Specifically, N different voltages V1 to VN are applied to organic photoconductive film <NUM> to image the color chart Ob2 each time the voltages are applied. This yields a determinant as expressed by (Equation <NUM>). The determinant includes color data that consists of a <NUM> × <NUM> matrix, the set of coefficients A that consists of a <NUM> × N matrix, and luminance data that consists of an N × <NUM> matrix. It is to be noted that the determinant of (Equation <NUM>) regards each color as one pixel. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

The set of coefficients A expressed by (Equation <NUM>) is derived by solving the determinant of (Equation <NUM>) using a pseudo inverse matrix. Because no solution satisfies all the equations for this determinant, a solution that minimizes the square error over all the equations is adopted.

The manners of deriving the set of coefficients A are not limited to the above but may involve deep learning. For example, the set of coefficients A may be derived by imaging the color chart Ob2 of multiple colors using image capturer <NUM>, and performing learning using, as an input, multiple luminance data items obtained by the imaging, and using, as label data, data corresponding to the multiple colors. In this case, the object to be imaged does not need to be a color chart but may be any sample object in which color data corresponding to each color is known. For example, images of such a sample object captured with a general color camera may be used to assign the luminance values of the R, G, and B components of the color camera to the left side of (Equation <NUM>). Using such an object enables learning of data closely reflecting the actual imaging scene, so that a more closely reproduced color image can be generated.

Now, a result of image generation by image generation device <NUM> will be described.

<FIG> is a diagram showing an example of an image generated by image generation device <NUM>. In <FIG>, (a) shows a label image of the object Ob1, while (b) shows an image generated by image generation device <NUM>.

The image shown in (b) in <FIG> was obtained by imaging the object Ob1 twice while two voltages of different voltage values were applied to organic photoconductive film <NUM>. It is to be noted that the set of coefficients A, which is a transformation matrix, was obtained by assuming the label image of the object Ob1 to be a two-color image including the (R + G) component and the B component. Organic photoconductive film <NUM> used had a two-layer structure including a layer for detecting visible light and a layer for detecting near-infrared light.

As shown, the image generated by image generation device <NUM> successfully reproduces the colors of the object Ob1.

Now, image generation device <NUM> in variation <NUM> of embodiment <NUM> will be described. In an example to be described in variation <NUM>, the values of the voltages applied to organic photoconductive film <NUM> are changed according to the scene in which the imaging is performed.

<FIG> is a schematic diagram showing wavelength-sensitivity characteristics of imaging element <NUM> in image generation device <NUM>.

(a) in <FIG> shows sensitivity characteristics in imaging in a light environment. In the example shown, imaging is performed using a wide wavelength range corresponding to the visible light range while voltages V1, V2, and V3 are applied to organic photoconductive film <NUM>. (b) in <FIG> shows sensitivity characteristics in imaging in an environment darker than the environment of (a). In the example shown, imaging is performed using a wavelength range close to the near-infrared range while voltages V4, V5, and V6 are applied to organic photoconductive film <NUM>. These different voltages V1 to V6 are applied by voltage generator <NUM> to organic photoconductive film <NUM>.

The set of voltages may be switched as preset in image generation device <NUM> between the voltages V1 to V3 and the voltages V4 to V6 for light times and dark times, respectively. Alternatively, the voltages V1 to V3 may initially be used for imaging, and if the imaging yields a dark color image Dc, the voltages V4 to V6 may then be used for imaging. That is, voltage generator <NUM> has information on multiple sets of voltage values and switches among the sets of voltage values. Exemplary sets of voltage values may be a first voltage value set (V1 to V3), and a second voltage value set (V4 to V6) for use in an imaging environment darker than the imaging environment for the first set.

Image generation device <NUM> may further include a sensor. The voltage value set may be selected based on information about correspondences between sensor values and voltage values, and on a sensor value obtained by the sensor. The voltage value set may also be selected by obtaining a sensor value provided by a sensor external to image generation device <NUM>. The voltage value set may also be switched in response to a user's input to image generation device <NUM>.

Conditions for changing the values of the voltages applied to organic photoconductive film <NUM> for imaging are not limited to the lightness of the environment. For example, if human skin is to be imaged, the voltages applied to organic photoconductive film <NUM> may be set such that a wavelength range close to the skin color can be used for the imaging.

Thus, as in image generation device <NUM> in variation <NUM>, imaging for various purposes can be performed by changing the voltages applied to organic photoconductive film <NUM> according to the scene in which imaging is performed.

Now, image generation device <NUM> in variation <NUM> of embodiment <NUM> will be described. In an example to be described in variation <NUM>, a voltage applied to organic photoconductive film <NUM> is modulated during exposure (within an exposure period) performed by image capturer <NUM>.

<FIG> is a diagram showing voltages applied to organic photoconductive film <NUM> during exposure performed by image capturer <NUM> in image generation device <NUM>. In the example shown in <FIG>, image capturer <NUM> changes an applied voltage during exposure, that is, while FDs <NUM> are storing electric charge.

As shown, imaging is performed by making three exposures. The first imaging is performed while voltage V1 and then voltage V2 are applied to organic photoconductive film <NUM>. Subsequently, the second imaging is performed while voltage V2 is applied to organic photoconductive film <NUM>, and the third imaging is performed while voltage V3 is applied.

In this manner, the voltage is modulated during the first exposure. For example, this can create a characteristic having both the sensitivity corresponding to the application of voltage V1 and the sensitivity corresponding to the application of voltage V2. According to image generation device <NUM> in variation <NUM>, sensitivity characteristics for a specific purpose can be created and used to obtain the luminance data D1 to D3 and generate the color image Dc.

Configurations of image generation device <NUM> in embodiment <NUM> will be described.

<FIG> is a schematic diagram showing image capturer 10A and voltage generator <NUM> in image generation device <NUM> in embodiment <NUM>.

Image capturer 10A includes: microlenses <NUM>; and imaging element <NUM> having pixels arranged in an array.

Imaging element <NUM> includes: silicon substrate <NUM>; FDs <NUM> provided on silicon substrate <NUM>; metal wires <NUM> and pixel electrodes <NUM> electrically connected to FDs <NUM>; organic photoconductive film <NUM> provided on pixel electrodes <NUM>; and transparent electrode <NUM> provided on organic photoconductive film <NUM>.

Organic photoconductive film <NUM> in this embodiment has a stacked structure including first organic photoconductive film 32a for detecting near-infrared light and second organic photoconductive film 32b for detecting visible light.

In this embodiment, second organic photoconductive film 32b is formed on first organic photoconductive film 32a. That is, second organic photoconductive film 32b for detecting visible light (RGB) is provided closer to the object Ob1 than first organic photoconductive film 32a for detecting near-infrared light (NIR) is. According to this structure, first organic photoconductive film 32a can detect near-infrared light after second organic photoconductive film 32b detects and eliminates visible light. This can improve near-infrared light detection performance.

In embodiment <NUM>, the number of voltages applied to organic photoconductive films 32a and 32b is greater than or equal to the number of organic photoconductive films 32a and 32b. For example, in embodiment <NUM>, three voltages V1 to V3 are applied to each of two organic photoconductive films 32a and 32b. Consequently, more sensitivity characteristics can be created than in the case in which organic photoconductive film <NUM> is single-layered. This enables a closely reproduced color image Dc to be generated using further accurate sensitivity characteristics.

<FIG> is a schematic diagram showing image capturer 10B and voltage generator <NUM> in image generation device <NUM> in a non - limiting example.

Image capturer 10B includes: microlenses <NUM>; and imaging element <NUM> having pixels arranged in an array.

Organic photoconductive film <NUM> in this non -limiting example has a stacked structure including first organic photoconductive film 32a for detecting near-infrared light (NIR) and second organic photoconductive film 32b for detecting visible light (RGB). Second organic photoconductive film 32b has a three-layer structure in which R layer 32b1, G layer 32b2, and B layer 32b3 are stacked in this order on pixel electrodes <NUM>. For example, R layer 32b1 detects the R component of light, G layer 32b2 detects the G component of light, and B layer 32b3 detects the B component of light.

In this embodiment, first organic photoconductive film 32a is formed on second organic photoconductive film 32b. That is, first organic photoconductive film 32a for detecting near-infrared light is provided closer to the object Ob1 than second organic photoconductive film 32b for detecting visible light is. According to this structure, second organic photoconductive film 32b can detect visible light after first organic photoconductive film 32a detects and eliminates near-infrared light. This can improve color reproducibility for visible light.

Thus, the embodiments of the present invention have been described above as examples of techniques according to the present invention. Aspects of the techniques include variations of the above embodiments, and combinations of elements of different embodiments.

The components of the image generation device illustrated in the above embodiments (in particular, circuits including data processor <NUM>) may be implemented in dedicated hardware or may be implemented by executing software (a program) appropriate for the components. The components may also be implemented by a program executor such as a microprocessor reading and executing a program recorded on a storage medium (or a recording medium), such as a hard disk or semiconductor memory.

The circuits in the image generation device may be integrated into a single circuit or may be separate circuits. These circuits may each be a general-purpose circuit or a special-purpose circuit. Processes performed by a certain component in the above embodiments may alternatively be performed by another component, for example. The order of performing processes in the above embodiments may be changed, or multiple processes may be performed in parallel.

Claim 1:
An image generation device (<NUM>), comprising:
a voltage generator (<NUM>) configured to generate a plurality of voltages (V1 V2 V3) each having a different voltage value;
an image capturer (<NUM>) configured to include an organic photoconductive film OPF (<NUM>) and a transparent electrode (<NUM>) in contact with said OPF (<NUM>), and further configured to perform imaging every time each of the plurality of voltages (V1 V2 V3) is applied by the voltage generator (<NUM>) to the organic photoconductive film OPF (<NUM>) by means of the transparent electrode (<NUM>);
a luminance data obtainer (<NUM>) configured to obtain a plurality of luminance data items (D1 D2 D3) corresponding to the plurality of voltages (V1 V2 V3) applied, each of the plurality of luminance data items (D1 D2 D3) being obtained from the imaging performed by the image capturer (<NUM>); and
a color image generator (<NUM>) configured to generate a color image (Dc) based on the plurality of luminance data items (D1 D2 D3),
wherein the organic photoconductive film OPF (<NUM>) is configured to photoelectrically convert light entering the image capturer (<NUM>) through the transparent electrode (<NUM>) comprised in said image capturer (<NUM>), and not through a color filter.