JP4123574B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus that captures an optical image. In particular, the present invention relates to a technique for optimally combining the pixel arrangement of an image pickup means, the color arrangement of a color filter, and the characteristics of an optical low-pass filter.
[0002]
[Prior art]
FIG. 16A is a configuration diagram illustrating a conventional single-plate imaging device.
In FIG. 16A, an optical low-pass filter 82 is disposed on the image space side of the photographing optical system 81. The optical low-pass filter 82 is configured by bonding a first filter 83 that birefringes light, a quarter-wave plate 84 that disturbs a polarization plane, and a second filter 85 that birefrings light.
[0003]
An imaging element 86 is disposed behind the optical low-pass filter 82 via a color filter 87. The color filter 87 is divided into a horizontal pitch Px and a vertical pitch Py according to the pixel position of the image sensor 86, and is color-coded into RGB three colors.
FIG. 16B is a diagram showing the color arrangement of the color filter 87. The color arrangement here is a color arrangement (so-called “Bayer arrangement”) in which the G component is arranged in a checkered pattern and the remaining R component and B component are arranged.
FIG. 16C is a diagram illustrating a “blurred image of a point image” by the optical low-pass filter 82 described above. The blurred image as shown in this figure is realized by the following optical actions (1) to (3).
[0004]
(1) The second filter 85 birefringes the optical image into a normal ray and an extraordinary ray, and shifts the image forming positions in the vertical direction by a distance Δy substantially equal to the vertical pitch Py.
[0005]
(2) The quarter-wave plate 84 converts the linearly polarized light divided by the second filter 85 into circularly polarized light and disturbs the polarization plane.
[0006]
(3) The first filter 83 birefringes the optical image that has passed through the quarter-wave plate 84 again into normal rays and extraordinary rays, and shifts the imaging position in the horizontal direction by a distance Δx that is substantially equal to the horizontal pitch Px. .
Due to the optical action of the optical low-pass filter 82, light of four sections is mixed and incident on one section of the color arrangement shown in FIG. As a result, a substantial light receiving range (hereinafter, this substantial light receiving range is referred to as a “light receiving window”) in one section of the color array is enlarged by about twice in the vertical and horizontal directions.
[0007]
FIGS. 17B to 17D are diagrams showing such a light receiving window for each RGB component. As shown in the figure, the arrangement of the light receiving windows for each color component extends about twice in the vertical and horizontal directions, and fills the entire light receiving surface without any gaps.
The image sensor 86 generates a smoothed pixel output for each region of these light receiving windows. Therefore, the high frequency component of the optical image is surely suppressed, and it is possible to effectively suppress the occurrence of false color and moire in the image output.
[0008]
[Problems to be solved by the invention]
Incidentally, in such a conventional example, as shown in FIG. 17B, the light receiving windows for the G component are formed so as to overlap each other. For this reason, the G component has a problem in that high frequency suppression of the spatial frequency works excessively and causes a significant decrease in resolution.
Therefore, Book It is an object of the present invention to provide an imaging apparatus that sufficiently suppresses false colors and moire and does not impair the resolution as much as possible.
[0009]
Another object of the present invention is to provide an imaging device that balances the suppression of false colors and the improvement of resolution in a Bayer arrangement such as primary colors.
Furthermore, it is an object of the present invention to provide an imaging device capable of making the light receiving window substantially square with respect to the first color component having the highest density.
[0010]
According to a fourth aspect of the present invention, in addition to the object of the third aspect, an object of the present invention is to provide an imaging apparatus capable of reliably suppressing false color and moire for other color components.
According to a fifth aspect of the present invention, in addition to the object of the third aspect, an object of the present invention is to provide an image pickup apparatus in which a square pixel image pickup device can be used.
[0011]
[Means for Solving the Problems]
(Claim 1)
The invention described in claim 1 The plurality of color components are arranged with the highest density of the first color component of the plurality of color components as compared with the other color components. In an imaging apparatus including a color filter and an imaging unit that captures an optical image transmitted through the color filter, A first filter for blurring a light image by incident light in a first direction, and a wavelength of light of a color component excluding the first color component out of the color components of the light image by incident light is different from the first direction. An optical low-pass filter having a second filter that blurs in two directions and emits the light to the color filter and transmits the light of the first color component as it is. It is characterized by that.
[0012]
In such a configuration, the optical low-pass filter blurs the other color components in the first direction and the second direction. For this reason, the occurrence of false colors and moire can be sufficiently suppressed for the other color components of the optical image.
On the other hand, the second filter is “ Among the color components of the light image by the incident light, the light of the color component excluding the first color component is selected, and the light is blurred in the second direction different from the first direction and emitted to the color filter. Transmit light of color component as it is " Characteristic Have . So As a result, the resolution in the second direction can be increased for the first color component.
[0013]
The first color component is arranged at the highest density on the color filter. Therefore, the sampling interval of the first color component in the imaging means is the finest, and the aliasing noise mixed in the sampling signal of the first color component is shifted to a higher frequency side than in the case of other color components. Therefore, for the first color component ,false There is little risk of color or moire. For the reasons described above, the invention according to claim 1 does not impair the resolution of the first color component as much as possible while sufficiently suppressing false color and moire.
[0014]
(Claim 2)
According to a second aspect of the present invention, there is provided an optical low-pass filter having a first filter that blurs the optical image in the horizontal direction and a second filter that blurs the optical image in the vertical direction, and a plurality of optical images that have passed through the optical low-pass filter. In an imaging apparatus including a color filter that performs color classification via a color arrangement of colors and an imaging unit that captures an optical image that has passed through the color filter, the color arrangement of the color filter includes a first color component arranged in a checkered pattern. , A Bayer arrangement in which the second color component and the third color component are arranged at the remaining positions, and when the horizontal pitch of the color arrangement is Px and the vertical pitch is Py, the first filter The first to third color components are horizontally blurred by a distance substantially equal to the horizontal pitch Px, and the second filter selects wavelengths of the second color component and the third color component of the optical image and is substantially equal to the vertical pitch Py. Just the distance Wherein the blur in the orthogonal direction.
[0015]
In such a configuration, the wavelength of the first color component is not selected in the second filter. Therefore, the first color component is blurred mainly by a distance substantially equal to Px in the horizontal direction. Due to such a horizontal blurring effect, the light receiving window for the first color component is stretched about twice in the horizontal direction.
By the way, as shown in FIG. 1A, in the Bayer array, the first color component is arranged every other horizontal section. Accordingly, by extending the light receiving window for the first color component approximately twice in the horizontal direction, the entire light receiving surface can be filled with the light receiving window for the first color component almost without overlapping as shown in FIG. It becomes possible.
[0016]
By forming the light receiving windows for the first color component without substantially overlapping in this way, the resolution of the first color component is not impaired more than necessary. In addition, since the light receiving windows are arranged with almost no gap, it is possible to sufficiently suppress false colors and moire generated in the first color component.
On the other hand, the second color component and the third color component are blurred horizontally and vertically by the first filter and the second filter. Due to such a blurring effect, the light receiving windows of the second color component and the third color component are extended approximately twice each in horizontal and vertical directions (approximately 4 times in area ratio).
[0017]
By the way, as shown in FIG. 1A, in the Bayer array, the second color component is arranged every other horizontal section and every other vertical section. Accordingly, the light receiving window for the second color component spreads approximately twice in the horizontal and vertical directions, so that the entire light receiving surface can be completely filled with the light receiving windows for the second color component as shown in FIG. 1C. It becomes possible.
Similarly, with respect to the light receiving window for the third color component, as shown in FIG. 1 (d), the entire light receiving surface is almost completely filled.
[0018]
With such an arrangement of the light receiving windows, the second color component and the third color component can be prevented from spoiling the resolution more than necessary, and generation of false colors and moire can be sufficiently suppressed.
As described above, in the invention described in claim 2, for all three color components in the Bayer array, a high-quality image signal that achieves both the effect of suppressing false colors and moire and the effect of improving resolution to the maximum extent. Can be obtained.
[0019]
(Claim 3)
According to a third aspect of the present invention, an optical low-pass filter having a first filter that blurs the optical image in the horizontal direction, a second filter that blurs the optical image in the horizontal or vertical direction, and an optical image that has passed through the optical low-pass filter. In the image pickup apparatus including a color filter that performs color classification through a color arrangement of a plurality of colors and an image pickup unit that picks up a light image that has passed through the color filter, the color filter includes the first color component having the highest density and the others The horizontal pitch Px of the color array is set to approximately twice the vertical pitch Py, and the first filter horizontally converts the optical image by a distance substantially equal to the horizontal pitch Px. The second filter is characterized in that the other color components in the light image are wavelength-selected and blurred in a horizontal or vertical direction by a distance substantially equal to the vertical pitch Py. That.
[0020]
In such a configuration, as shown in FIG. 2A, the horizontal pitch Px of the color array is set to substantially half of the vertical pitch Py. Therefore, by blurring the first color component by a distance substantially equal to Px in the horizontal direction by the first filter, the light receiving window for the first color component becomes substantially square as shown in FIG.
Therefore, for the first color component, it is possible to easily obtain a signal with a pixel aspect ratio of 1: 1 without performing complicated calculation processing such as aspect conversion.
[0021]
(Claim 4)
According to a fourth aspect of the present invention, in the imaging device according to the third aspect, the color arrangement of the color filters is different in the pitch between the same colors in the horizontal direction and the vertical direction with respect to the other color components. The second filter is a filter that blurs the other color components of the light image in the direction in which the pitch between the same colors is large.
In such a configuration, other color components are blurred by the second filter in the direction in which the pitch between the same colors is large. Therefore, as shown in FIGS. 2C and 2D, the light receiving windows of other color components do not overlap between the same colors, and the resolution of the other color components is not unnecessarily impaired.
[0022]
(Claim 5)
According to a fifth aspect of the present invention, in the imaging device according to the third or fourth aspect, the imaging means includes a two-dimensional array of light receiving elements with a pixel pitch Px on the light receiving surface, and one section of a color array. The transmitted light is received by two light receiving elements.
With such a configuration, it is possible to easily realize the imaging device according to claims 3 and 4 by using a general imaging device including square pixels.
[0023]
In each of the above-mentioned claims, a simple expression “blur only a distance substantially equal to P−” is used (“−” is replaced by x or y). More specifically, this means that the original optical image has a spatial frequency characteristic such that a light image substantially shifted by P- is superimposed.
In general, in the case of an optical low-pass filter using birefringence, the optical images are simply shifted and overlapped, so that the above-mentioned meanings can be applied as they are.
[0024]
On the other hand, in the case of an optical low-pass filter using a phase grating or the like, high-order components and light blurring (so-called halo) occur, so it cannot be said that two optical images are simply superimposed. However, in such a case as well, by designing a filter such as arranging the zero point of the spatial frequency characteristic in the vicinity of [1 / (2P−)] or making the shoulder portion of the low-pass characteristic the same, the “original It is possible to realize a “spatial frequency characteristic that can superimpose a P-shifted optical image on the optical image”.
(Claim 6)
According to a sixth aspect of the present invention, an optical low-pass filter, a color filter that color-codes a light image that has passed through the optical low-pass filter through a color arrangement of a plurality of colors, and a light image that has passed through the color filter are captured. In the imaging apparatus including the imaging unit, the color arrangement of the color filter is a color arrangement in which the first color components are arranged at the highest density and the other color components are arranged at remaining positions, and the optical filter The low pass filter A first filter that blurs a light image in a first direction on a light receiving surface of the imaging unit; and a second filter that blurs the light of the other color components in a second direction different from the first direction. The range in which the respective color components of the light of one color component and the light of the other color component are blurred by the optical low-pass filter is substantially the same over the entire light receiving surface of the imaging unit without overlapping the light of the same color component. Fill without gaps It is characterized by that.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0026]
(First embodiment)
The first embodiment is claimed in claims 1 and 2. , 6 It is embodiment corresponding to invention described in (1).
FIG. 3A is a diagram illustrating the configuration of the first embodiment.
In FIG. 3A, an optical low-pass filter 12 is disposed on the image space side of the photographing optical system 11. The optical low-pass filter 12 is configured by bonding a first filter 13 that birefringes light, a quarter-wave plate 14 that disturbs a polarization plane, and a second filter 15 that has wavelength selectivity.
[0027]
An imaging element 16 is disposed behind the optical low-pass filter 12 via a color filter 17. The color filter 17 is divided into a horizontal pitch Px and a vertical pitch Py according to the pixel position of the image sensor 16 and is color-coded into RGB three colors.
FIG. 3B is a diagram showing the color arrangement. The color arrangement here is a color arrangement (so-called “Bayer arrangement”) in which the G component is arranged in a checkered pattern and the remaining R component and B component are arranged.
FIG. 3C is a diagram showing a “blurred image of a point image” by the optical low-pass filter 12 described above. The blurring state as shown in this figure is realized by the following optical actions (1) to (3).
[0028]
(1) The second filter 15 selects the wavelength of the RB component and blurs the image formation position of the RB component vertically by a distance Δy equal to the vertical pitch Py. On the other hand, the G component passes through the second filter 15 almost as it is. As the filter having such characteristics, for example, a wavelength selective phase grating described in Japanese Patent Laid-Open No. 5-66370 can be used.
[0029]
(2) The quarter-wave plate 14 disturbs the polarization plane of the linearly polarized light component that may be generated by the diffraction action or refraction action of the second filter 15. If the linearly polarized light component is not so much generated in the second filter 15, the quarter wavelength plate 14 may be omitted.
[0030]
(3) The first filter 13 divides the RGB components that have passed through the quarter-wave plate 14 into normal rays and extraordinary rays, and shifts the image formation positions in the horizontal direction by a distance Δx equal to the horizontal pitch Px.
Due to the blurring effect as described above, light of two sections is mixed and incident on one section of the G component shown in FIG. Further, light of four sections is mixed and incident on one section of the RB component.
[0031]
As a result, the light receiving windows of the RGB components are enlarged as shown in FIGS. 4B to 4D, and each fills the entire light receiving surface without any gap.
Therefore, there is no unnecessary overlap in the light receiving windows of the RGB components, and the resolution of all three types of color components can be increased as much as possible. At this time, almost no gap is generated in the light receiving windows of the RGB components, so that false colors and moire can be sufficiently suppressed for all three types of color components.
[0032]
In particular, when compared with the conventional example (FIG. 17), the G component light receiving window does not overlap at all in the first embodiment. Accordingly, it is possible to generate a particularly good image signal by further increasing the resolution of the G component that contributes most to the substantial resolution.
Next, another embodiment will be described.
[0033]
(Second Embodiment)
The second embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 5A is a diagram illustrating a configuration of the second embodiment.
In FIG. 5A, an optical low-pass filter 22 is disposed on the image space side of the photographing optical system 11. The optical low-pass filter 22 is configured by bonding a first filter 23 that birefringes light, a quarter-wave plate 24 that disturbs a polarization plane, and a second filter 25 having wavelength selectivity.
[0034]
A square pixel imaging element 26 is disposed behind the optical low-pass filter 22 via a color filter 27. The pixel output output from the image sensor 26 is converted into a pixel output having an aspect ratio of 2 by adding two vertical pixels during scanning or after completion of scanning.
The surface of the color filter 27 is divided into a horizontal pitch Px and a vertical pitch Py (= 2Px) in alignment with the two vertical pixels, and each of them is color-coded into three RGB colors.
[0035]
FIG. 5B is a diagram showing the color arrangement. The odd-numbered rows of the color filter 27 are color-coded as “GRGR...”, And the even-numbered rows are color-coded as “GBGB.
FIG. d ) Is a diagram showing a “blurred image of a point image” by the optical low-pass filter 22 described above. The blurring state as shown in this figure is realized by the following optical actions (1) to (3).
[0036]
(1) The second filter 25 selects the wavelength of the RB component and blurs the image formation position of the RB component vertically by a distance Δy equal to the vertical pitch Py. On the other hand, the G component passes through the second filter 25 almost as it is. As the filter having such characteristics, for example, a wavelength selective phase grating described in Japanese Patent Laid-Open No. 5-66370 can be used.
[0037]
(2) The quarter wavelength plate 24 disturbs the polarization plane of the linearly polarized light component that may be generated by the diffraction action or the refraction action of the second filter 25. If the linearly polarized light component does not occur so much in the second filter 25, the quarter wavelength plate 24 may be omitted.
[0038]
(3) The first filter 23 divides the RGB components that have passed through the quarter-wave plate 24 into normal rays and extraordinary rays, and horizontally shifts the imaging positions of each other by a distance Δx equal to the horizontal pitch Px.
Due to the blurring effect as described above, light for two sections is mixedly incident on one section of the G component shown in FIG. Further, light of four sections is mixed and incident on one section of the RB component.
[0039]
As a result, the light receiving windows of the RGB components are enlarged as shown in FIGS. 6B to 6D, and each fills the entire light receiving surface without any gap.
Therefore, there is no unnecessary overlap in the light receiving windows of the RGB components, and the resolution of all three types of color components can be maximized. At this time, since no gap is generated in the light receiving windows of the RGB components, false colors and moire can be sufficiently suppressed for all three types of color components.
[0040]
At this time, the G component light receiving window has a square shape as shown in FIG. Therefore, for the G component image signal, it is possible to directly generate a square pixel image signal without performing complicated processing such as aspect conversion. Therefore, it is possible to realize a particularly suitable imaging device in a computer-related field that often handles square pixel images.
[0041]
Further, the blurring direction of the second filter 25 is set to “a vertical direction in which the pitch between the same colors with respect to the RB component is much wider”. Therefore, the light receiving window for the RB component does not overlap, and the resolution of the RB component is not impaired more than necessary.
In addition, since the light transmitted through one section of the color filter 27 is received by two light receiving elements 28, it is possible to use a general square pixel imaging element 26.
Next, another embodiment will be described.
[0042]
(Third embodiment)
The third embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 7 is a diagram for explaining the third embodiment.
The feature point of the configuration in the third embodiment is that the odd-numbered rows of the color filter are color-coded as “GRGB ••” and the even-numbered rows are color-coded as “GBGR ••”. Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
[0043]
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 7, and each fills the entire light receiving surface without any gap. Therefore, also in the third embodiment, it is possible to obtain the same effect as in the second embodiment.
An effect unique to the third embodiment is that the light receiving windows of the RB component are arranged obliquely while being shifted by half phase. By such an arrangement of the light receiving windows, it is possible to increase the substantial resolution of the RB component.
Next, another embodiment will be described.
[0044]
(Fourth embodiment)
The fourth embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 8 is a diagram for explaining the fourth embodiment.
The feature point of the configuration in the fourth embodiment is that the odd-numbered lines of the color filter are color-coded as “GRGR...” And the even-numbered lines are color-coded as “BGBG. Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
[0045]
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 8, and each fills the entire light receiving surface without any gap. Therefore, also in the fourth embodiment, it is possible to obtain the same effect as in the second embodiment.
Further, an effect peculiar to the fourth embodiment is that the G component light receiving windows are arranged in an oblique lattice. By such an arrangement of the light receiving windows, it is possible to increase the substantial resolution of the G component.
[0046]
(Fifth embodiment)
The fifth embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 9 is a diagram for explaining the fifth embodiment.
The structural features in the fifth embodiment are the following two points.
[0047]
(1) The horizontal lines of the color filters are color-coded in stripes with “GRGB.
[0048]
(2) The blurring direction of the second filter is set to a horizontal direction in which the same color pitch of the RB component is wide.
Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 9, and the entire light receiving surface is filled without any gaps. Therefore, also in the fifth embodiment, it is possible to obtain the same effect as in the second embodiment.
[0049]
In particular, the effect peculiar to the fifth embodiment is that the vertical phase of the light receiving window for the RB component matches the vertical phase of the light receiving window for the G component. As described above, since the mutual vertical phases coincide with each other in advance, it is possible to easily generate an image signal in which all the RGB components are aligned in the same phase.
Next, another embodiment will be described.
[0050]
(Sixth embodiment)
The sixth embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 10 is a diagram for explaining the sixth embodiment.
The structural feature points in the sixth embodiment are the following two points.
[0051]
(1) The odd-numbered lines of the color filter are color-coded as “GRGB...” And the even-numbered lines are color-coded as “GBGR.
[0052]
(2) The blurring direction of the second filter is set to a horizontal direction in which the same color pitch of the RB component is wide.
Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 10, and each fills the entire light receiving surface without any gap. Therefore, in the sixth embodiment, it is possible to obtain the same effect as in the second embodiment.
[0053]
An effect unique to the sixth embodiment is that the light receiving windows of the RB component are arranged obliquely while being shifted by half phase. By such an arrangement of the light receiving windows, it is possible to increase the substantial resolution of the RB component.
Furthermore, in the sixth embodiment, the vertical phase of the light receiving window for the RB component matches the vertical phase of the light receiving window for the G component. As described above, since the mutual vertical phases coincide with each other in advance, it is possible to easily generate an image signal in which all the RGB components are aligned in the same phase.
Next, another embodiment will be described.
[0054]
(Seventh embodiment)
The seventh embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 11 is a diagram for explaining the seventh embodiment.
The structural features in the seventh embodiment are the following two points.
[0055]
(1) The odd-numbered lines of the color filter are color-coded as “GRGB...” And the even-numbered lines are color-coded as “RGBG.
[0056]
(2) The blurring direction of the second filter is set to a horizontal direction in which the same color pitch of the RB component is wide.
Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 11, and each of the light receiving surfaces is completely filled with no gap. Therefore, also in the seventh embodiment, it is possible to obtain the same effect as in the second embodiment.
[0057]
In addition, in the seventh embodiment, the light receiving windows for the G component are arranged in an oblique lattice. Further, the light receiving windows for the RB component are arranged obliquely while being shifted by ¼ phase. Such an arrangement of the light receiving windows makes it possible to increase the substantial resolution of the RGB components.
Furthermore, in the seventh embodiment, the vertical phase of the light receiving window for the RB component matches the vertical phase of the light receiving window for the G component. As described above, since the mutual vertical phases coincide with each other in advance, it is possible to easily generate an image signal in which all the RGB components are aligned in the same phase.
Next, another embodiment will be described.
[0058]
(Eighth embodiment)
An eighth embodiment is the claim 1 It is embodiment corresponding to invention of -6.
FIG. 12 is a diagram for explaining the eighth embodiment.
The feature of the configuration in the eighth embodiment is that the color arrangement is shifted by half a phase in the vertical direction between the odd and even columns of the color filter.
[0059]
On the image sensor side, the block of the light receiving element 28 is set as shown in FIG. 13B in accordance with the phase shift of the color arrangement. By adding the pixel outputs in units of blocks of the light receiving elements 28 as described above, it is possible to generate pixel outputs having a color array as shown in FIG. 13A while using square pixel imaging elements.
The addition operation here may be performed while performing the vertical transfer operation of the pixel output independently for the odd-numbered columns and the even-numbered columns, or may be performed when image processing is performed outside the imaging device. Good.
[0060]
Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 12, and each fills the entire light receiving surface without any gap. Therefore, also in the eighth embodiment, it is possible to obtain the same effect as in the second embodiment.
[0061]
Moreover, in the eighth embodiment, the vertical phase of one RB component light receiving window matches the vertical phase of two G component light receiving windows. As described above, since the mutual vertical phases coincide with each other in advance, it is possible to easily generate an image signal in which all the RGB components are aligned in the same phase.
Next, another embodiment will be described.
[0062]
(Ninth embodiment)
Ninth Embodiment is Claim 1 It is embodiment corresponding to invention of -6.
FIG. 14 is a diagram for explaining the ninth embodiment.
The structural features in the ninth embodiment are the following two points.
[0063]
(1) The color arrangement is shifted by a half phase in the vertical direction between the odd and even columns of the color filter.
[0064]
(2) The R component and the B component are arranged in a checkered pattern on the even columns.
Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
In such a configuration, the light receiving windows of the RGB components are enlarged as shown in FIG. 14, and each fills the entire light receiving surface without any gap. Therefore, also in the ninth embodiment, it is possible to obtain the same effect as in the second embodiment.
[0065]
In addition, in the ninth embodiment, the vertical phase of one RB component light receiving window coincides with the vertical phase of two G component light receiving windows. As described above, since the mutual vertical phases coincide with each other in advance, it is possible to easily generate an image signal in which all the RGB components are aligned in the same phase.
In the ninth embodiment, the light receiving windows for the RB component are arranged obliquely while being shifted by a half phase. By such an arrangement of the light receiving windows, it is possible to increase the substantial resolution of the RB component.
Next, another embodiment will be described.
[0066]
(Tenth embodiment)
The tenth embodiment claims 1 It is embodiment corresponding to invention of -6.
FIG. 15 is a diagram for explaining the tenth embodiment.
The structural features in the tenth embodiment are the following three points.
[0067]
(1) The color arrangement is shifted by a half phase in the vertical direction between the odd and even columns of the color filter.
[0068]
(2) R component and B component are arranged in vertical stripes on even columns.
[0069]
(3) The blurring direction of the second filter is set to the horizontal direction in which the same color pitch of the RB component is wide.
Since the other configuration is the same as that of the second embodiment, description of the configuration here is omitted.
In such a configuration, each light receiving window of the RGB components is enlarged as shown in FIG. 15, and each fills the entire light receiving surface without any gap. Therefore, also in the tenth embodiment, it is possible to obtain the same effect as in the second embodiment.
Moreover, in the tenth embodiment, the horizontal phase of one RB component light receiving window matches the horizontal phase of two G component light receiving windows. As described above, since the horizontal phases of each other coincide with each other in advance, it is possible to easily generate an image signal in which all the RGB components are aligned in the same phase.
[0070]
(Variations of embodiments, etc.)
In each of the above-described embodiments, the distance for blurring the optical image is made coincident with Px and Py, so that no gap or overlap occurs in the light receiving window, and the resolution of the imaging device and the aperture ratio of the light receiving window are maximized. Can be obtained.
However, the present invention is not limited to this. In general, the effect of the present invention can be obtained by making the distance for blurring the optical image substantially equal to Px and Py. For example, the distance Δx that blurs the optical image in the horizontal direction and the distance Δy that blurs the optical image in the vertical direction
(0.6Px) ≦ Δx ≦ (1.5Px)
(0.6Py) ≦ Δy ≦ (1.5Py)
Even if it is set within the range, it becomes possible to suppress false colors and moiré.
[0071]
Moreover, although each embodiment mentioned above demonstrated the case where the filter which birefringes light was used as a 1st filter, this invention is not limited to this. In general, any optical element that blurs a light image by a predetermined distance can be used as an optical low-pass filter. For example, an optical low-pass filter using a phase grating may be used.
[0072]
Furthermore, although each embodiment mentioned above demonstrated the case where a wavelength selective phase grating was used as a 2nd filter, this invention is not limited to this. In general, any optical element whose blur amount varies depending on the wavelength can be used as the second filter.
Further, in each of the above-described embodiments, the bonding is performed in the order of “second filter → first filter” along the optical path, but is not limited thereto. This order may be reversed, or both filters may be arranged independently without being bonded. (However, when using a phase grating, it is necessary to pay attention to the fact that the interval between the image sensor and the phase grating is adjusted to the set value at the time of designing the phase grating.)
Further, in each of the above-described embodiments, three types of color components have been described, but the present invention is not limited to this. For example, a mode in which two colors (for example, when the present invention is applied to one image sensor of a two-plate imaging device) or four or more colors is assigned as color components is conceivable.
In the above-described embodiment, one section of the color array is allocated to two light receiving elements, but the present invention is not limited to this. For example, as shown in FIG. 13C, one section of the color array may be configured by one light receiving element. Of course, one section of the color array may be composed of blocks of three or more light receiving elements.
[0073]
【The invention's effect】
(Claim 1)
In the first aspect of the present invention, the second filter has a wavelength selectivity that “the blur amount of the first color component is smaller than the blur amount of the other color components or is effectively zero”. Therefore, for the first color component, the blur amount in the second direction is reduced, and the resolution in the second direction can be increased.
[0074]
In the imaging unit, since the sampling interval of the first color component is the smallest, aliasing noise generated in the sampling signal of the first color component is shifted to a higher frequency side than in the case of other color components. Therefore, the first color component is less likely to cause false color or moire even if the blur amount is reduced as described above.
As described above, according to the first aspect of the present invention, it is possible to realize an imaging apparatus that sufficiently suppresses false colors and moire and does not impair the resolution as much as possible.
[0075]
(Claim 2)
In the second aspect of the present invention, as shown in FIGS. 1B to 1D, the entire light receiving surface of each of the three types of color components forming the Bayer array can be covered with the light receiving window substantially without overlapping. Therefore, for all three color components, the resolution is not impaired more than necessary, and false colors and moire can be sufficiently suppressed.
As described above, in the invention according to claim 2, it is possible to obtain a high-quality image signal in which the effect of suppressing false color and moire and the effect of improving resolution are made compatible to the maximum for all three types of color components. It becomes possible.
[0076]
(Claim 3)
In the invention according to claim 3, the light receiving window for the first color component is substantially square. Therefore, for the first color component, it is possible to easily obtain an image signal having a pixel aspect ratio of 1: 1 without performing complicated calculation processing such as aspect conversion.
Therefore, according to the third aspect of the present invention, it is possible to realize an imaging apparatus suitable for a computer-related field or the like that often handles square pixel images.
[0077]
(Claim 4)
In the fourth aspect of the invention, the second filter causes the other color components to be blurred in the direction in which the pitch between the same colors is large. For this reason, the light receiving windows of other color components hardly overlap between the same colors, and the resolution of the other color components can be increased as much as possible.
[0078]
(Claim 5)
According to the fifth aspect of the present invention, since one section of the color array is received by two light receiving elements, it is possible to use a general image sensor composed of square pixels. Therefore, it is not necessary to use an image pickup element composed of special rectangular pixels, and the image pickup apparatus according to claims 3 and 4 can be easily realized.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS , 6 It is a figure explaining invention of description.
FIG. 2 6 It is a figure for demonstrating invention described in (2).
FIG. 3 is a diagram showing a configuration of the first exemplary embodiment.
FIG. 4 is a diagram illustrating the operation of the first embodiment.
FIG. 5 is a diagram illustrating a configuration of a second embodiment.
FIG. 6 is a diagram for explaining the operation of the second embodiment.
FIG. 7 is a diagram for explaining a third embodiment.
FIG. 8 is a diagram for explaining a fourth embodiment;
FIG. 9 is a diagram for explaining a fifth embodiment;
FIG. 10 is a diagram for explaining a sixth embodiment.
FIG. 11 is a diagram for explaining a seventh embodiment.
FIG. 12 is a diagram (1/2) for explaining an eighth embodiment;
FIG. 13 is a diagram (2/2) for explaining the eighth embodiment;
FIG. 14 is a diagram for explaining a ninth embodiment.
FIG. 15 is a diagram for explaining a tenth embodiment;
FIG. 16 is a diagram illustrating a configuration of a conventional column.
FIG. 17 is a diagram illustrating the operation of a conventional example.

Claims (6)

A color filter in which a plurality of color components are arranged with the highest density of the first color component of the plurality of color components as compared to the other color components ;
In an imaging apparatus comprising imaging means for imaging a light image transmitted through the color filter,
A first filter for blurring a light image by incident light in a first direction, and a wavelength of light of a color component excluding the first color component out of the color components of the light image by incident light is different from the first direction. An imaging apparatus comprising: an optical low-pass filter having a second filter that blurs in two directions and emits the light to the color filter and transmits the light of the first color component as it is. An optical low-pass filter having a first filter that blurs the optical image in the horizontal direction and a second filter that blurs the optical image in the vertical direction;
A color filter for color-coding the optical image that has passed through the optical low-pass filter through a color arrangement of a plurality of colors;
In an imaging device comprising an imaging means for imaging a light image that has passed through the color filter,
The color arrangement of the color filter is a Bayer arrangement in which the first color components are arranged in a checkered pattern, and the second color components and the third color components are arranged in the remaining positions.
When the horizontal pitch of the color array is Px and the vertical pitch is Py,
The first filter is:
Blur the first to third color components of the light image in the horizontal direction by a distance substantially equal to the horizontal pitch Px;
The second filter is
An imaging apparatus, wherein the second color component and the third color component of an optical image are wavelength-selected and blurred in a vertical direction by a distance substantially equal to the vertical pitch Py. An optical low-pass filter having a first filter that blurs the optical image in the horizontal direction and a second filter that blurs the optical image in the horizontal or vertical direction;
A color filter for color-coding the optical image that has passed through the optical low-pass filter through a color arrangement of a plurality of colors;
In an imaging device comprising an imaging means for imaging a light image that has passed through the color filter,
The color filter is
It is composed of the color arrangement of the first color component with the highest density and the other color components, and when the horizontal pitch of the color arrangement is Px and the vertical pitch is Py, Py is set to approximately twice Px. And
The first filter is:
Blur the optical image in the horizontal direction by a distance substantially equal to the horizontal pitch Px,
The second filter is
An imaging apparatus, wherein the other color components in the optical image are wavelength-selected and blurred in a horizontal or vertical direction by a distance substantially equal to the vertical pitch Py. The imaging device according to claim 3.
The color arrangement of the color filter is:
Regarding the other color components, the pitch between the same colors is different in the horizontal direction and the vertical direction,
The second filter is
An image pickup apparatus characterized by being a filter that blurs the other color components of the optical image in a direction in which the pitch between the same colors is large. In the imaging device according to claim 3 or 4,
The imaging means includes
An image pickup apparatus, wherein light receiving elements are two-dimensionally arranged at a pixel pitch Px on a light receiving surface, and transmitted light for one section of the color array is received by the two light receiving elements. An optical low-pass filter;
A color filter for color-coding the optical image that has passed through the optical low-pass filter through a color arrangement of a plurality of colors;
In an imaging device comprising an imaging means for imaging a light image that has passed through the color filter,
The color arrangement of the color filter is a color arrangement in which the first color components are arranged at the highest density and the other color components are arranged at the remaining positions.
The optical low-pass filter includes a first filter that blurs the light image in a first direction on a light receiving surface of the imaging unit, and a second filter that blurs the light of the other color components in a second direction different from the first direction. With a filter,
The range in which the color components of the light of the first color component and the light of the other color components are blurred by the optical low-pass filter is the entire light receiving surface of the imaging unit without overlapping the light of the same color component. An image pickup apparatus that fills up almost without any gap .

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