JPH04304089A - Signal interpolation device - Google Patents

Abstract

PURPOSE:To reduce the false color signal occurring at the edge part of an object even when the size of high frequency component of the object occupies larger proportion than that of low frequency component or not to degrade the improving effect on the false color signal at the peripheral part of the object where the brightness changes sharply. CONSTITUTION:An optical low-pass filter 12 provided on the front surface of an imaging device 2 combined with plural kinds of color filters reduces the component intruding as a side band component from spacial frequency components of the object within the bands of low-pass filters 7, 8 which are conversion means when a factor is determined. When a detection circuit 14 does not detect the sharp change of the object, a gate circuit 13 operates to interpolate with the average value of the back and forth picture signals obtained from a correction circuit 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal interpolation device suitable for reducing color moire that occurs in a single-chip color camera using a solid-state image sensor.

0002

2. Description of the Related Art Single-chip color cameras that use only one solid-state image sensor to obtain color video signals are widely used in home video movies and other applications. In such a camera, each pixel of the solid-state image sensor is periodically associated with several types of color filters that transmit different light. Therefore, for color signals obtained by calculation between pixel signals corresponding to different color filters, the spatial sampling frequency is 1/2 to 1/2 of the pixel sampling frequency unique to the image sensor.
It drops to 3. As a result, sideband components generated due to sampling are likely to be mixed into each color signal, and false color signals, ie, color moiré, generated at edges of the object, etc., become a problem in reproduced images.

[0003] As a method for reducing color moire in a single-panel color camera, there is a technique disclosed in, for example, Japanese Patent Application Laid-Open No. 131819/1982 or Japanese Patent Application No. 262158/1999. The above-mentioned Japanese Patent Application Laid-Open No. 54-131819 corrects either the signals obtained before or after the pixel signal, but
Next, the technique disclosed in Japanese Patent Application No. 1-262158 will be briefly explained using FIGS. 2, 3, and 4. Figure 2
is a diagram showing the configuration of the color moire improvement method of the above technology, in which 1 is a lens, 2 is an image sensor, 3 and 4 are separation circuits,
5 and 6 are correction circuits, 7 and 8 are low-pass filters, and 9, 10, and 11 are a division circuit, a multiplication circuit, and an addition circuit, respectively. FIG. 3 is a diagram showing an example of a color filter for a single-chip color camera in the prior art, and FIG.
FIG. 3 is a diagram showing an example of frequency components of an output signal obtained from an image sensor.

Here, as shown in FIG. 3, the color filter has transmitted light of W (white), G (green), Cy (cyan), and Y.
e (yellow) microfilters are arranged in a repeating pattern of 2 vertical pixels x 2 horizontal pixels, and each microfilter corresponds to each pixel of the image sensor 2. It is also assumed that the image sensor 2 is capable of simultaneously and separately extracting two consecutive lines of pixel signals.

When using the color filter shown in FIG. 3, the spatial sampling functions lw(x) and lg(x) of each pixel of W, G, Cy, and Ye considering only the horizontal component are
, lc(x), and ly(x) are each expressed by the following equations.

[0006]

[Math 1]

[0007]

[Math 2]

[0008] Here, Px is the horizontal pixel pitch of the image sensor 2, and dx is the horizontal aperture size of the pixels. Expanding these equations into a Fourier series gives the following:

[0009]

[Math 3]

0010

[Math 4]

Here, the function representing the change in the horizontal direction of the subject is s(x), and the functions representing the changes in the transmitted light component of each color filter are sw(x) and sg, respectively.
(x), sc(x), sy(x), functions representing changes in each pixel signal swo(x), sgo(x), sc
o(x) and syo(x) are each expressed by the following equations.

0012

[Math 5]

[0013]

[Math 6]

[0014]

[Math 7]

[0015]

[Math. 8]

From equations (3) to (8), functions Swo(f) and Sgo(
f), Sco(f), and Syo(f) are each expressed as in the following equations.

[0017]

[Math. 9]

[0018]

[Math. 10]

[0019]

[Math. 11]

[0020]

[Math. 12]

However, Sw(f), Sg(f), Sc(
f) and Sy(f) are sw(x), sg(x), respectively
It is a function that represents the frequency component of sc(x) and sy(x), and * is a convolution integral operation (f1(x)*f2(x)=
∫f1(y)·f2(x-y)dy: convolution). Equation (9), Equation (10), (1
As is clear from the comparison of equations 1) and (12), Swo
(f) or Sco(f) and Sgo(f) or S
yo(f) is the phase of odd-numbered components of the harmonic sideband components generated due to sampling that differs by π. Therefore, when the subject is monochrome and the horizontal frequency component S(f) is as shown in FIG. 4(a), the frequency components of the W, G, Cy, and Ye pixel signals are as shown in FIG. 4(b). ), as shown in FIGS. 4(c), 4(d), and 4(e). Note that here, R (red) for a monochrome subject is used.
, G (green), and B (blue) sensitivity ratio was 2:2:1.

In order to obtain, for example, the B signal using the above pixel signal, the calculation shown in the following equation, ie

[0023]

[Math. 13]

It is sufficient to perform the following, and the frequency component SB(f)
is shown in FIG. 4(f). As is clear from FIG. 4(f), sB(x) has larger odd-order sideband components than the baseband B signal. Among the sideband components, components mixed into the baseband signal within the band of the chroma signal of the NTSC system (usually within 0.5 MHz in a single-chip color camera) cause color moire in the B signal. Therefore, if it is possible to prevent odd-numbered sideband components from being mixed into the baseband signal in a band of 0.5 MHz or less, color moiré can be removed.

Therefore, in the configuration shown in FIG. 2, the output signal of the image sensor 2 that passes through the lens 1 and corresponds to the subject image is separated into, for example, W and G pixel signals by the separation circuits 3 and 4, and then corrected. It is added to low-pass filters 7 and 8 via circuits 5 and 6, and the respective low frequency components are taken out. Here, an example of the correction circuits 5 and 6 adds an average signal of the previous and subsequent pixel signals, which is a general interpolation signal, between the individual pixel signals obtained from the separation circuits 3 and 4 in synchronization with the drive pulse. It is something to add. The low frequency components extracted by the low-pass filters 7 and 8 are shown in FIGS. 4(b) and 4(c), for example.
) is the shaded area. In addition, the low-pass filter 7
, 8 may separate the low frequency components of the input signal and then detect the power of the low frequency components.

At this time, if the horizontal frequency component S(f) of the subject is such that the low frequency component is relatively large and the high frequency component is small, as shown in FIG. As is clear from the observations in (b) and (c), the ratio of the sideband components mixed in the low frequency components extracted by the low-pass filters 7 and 8 to the baseband components is sufficiently small. Therefore, the ratio obtained by adding the output signals of the low-pass filter 7 and the low-pass filter 8 to the dividing circuit 9 is approximately a value close to the ratio of the W component and the G component of the subject. In this way, the ratio of the W low frequency component to the G low frequency component obtained by the division circuit 9 is multiplied by the G pixel signal obtained from the separation circuit 4 by the multiplication circuit 10. As a result, from the multiplication circuit 10,
As shown in (g), the magnitude of the baseband component is approximately equal to the magnitude of the W component of the subject shown in Figure 4(b), and the phase of the odd-numbered sideband component is opposite to that in Figure 4(b). A signal with frequency components is obtained. If the output signal of the multiplication circuit 10 obtained in this way is added to the W pixel signal obtained from the separation circuit 3 by the addition circuit 11, the result is as shown in FIG.
As shown in (h), a W signal with sufficiently reduced odd-order sideband components is obtained. If the odd-numbered sideband components of each pixel signal are reduced in the same way, using these signals (13
) Also in the B signal obtained by calculating the equation, odd-numbered sideband components are reduced and color moiré is significantly improved.

However, as shown in FIG. 5(a),
If the frequency component of the subject is large even in the high frequency range, the frequency components of the W and G pixel signals are as shown in FIGS. 5(b) and 5(c), respectively. At this time, in the low frequency components of W and G obtained from the low-pass filter 7 and the low-pass filter 8, the ratio of the sideband component to the baseband component is large, as shown in the shaded areas in FIGS. 5(b) and 5(c). Therefore, the magnitude of the signal obtained from the division circuit 9 is different from the ratio of the W component and the G component of the subject. Therefore, the frequency component of the signal obtained by multiplying the output signal of the division circuit 9 by the G pixel signal obtained from the separation circuit 4 and adding it to the multiplication circuit 10 is
), the magnitude of the baseband component is as shown in Figure 5(b).
It will be slightly different from the one. As a result, the frequency component of the signal obtained by adding the output signal of the multiplication circuit 10 and the W pixel signal obtained from the separation circuit 3 by the addition circuit 11 is the baseband component, as shown in FIG. 5(e). The size is slightly different from the original W component, and some odd-order sideband components remain.

Furthermore, the change in brightness in the horizontal direction is shown in FIG. 6(a).
), the position of x=2n・Px corresponds to the pixel of W, and x=
Consider the case where the position of (2n+1)·Px corresponds to the G pixel (where n is an integer). Here, the change in brightness is x
It is assumed that x exists between =(2n-1)·Px and x=2n·Px. At this time, in the conventional configuration shown in FIG. 2, W and G obtained from the separation circuit 3 and the separation circuit 4
The pixel signals shown in FIGS. 6(b) and 6(c) are indicated by diagonal lines, respectively. Further, the output waveforms obtained by applying the output signals of the separation circuits 3 and 4 to the correction circuits 5 and 6 are shown by broken lines in FIGS. 6(b) and 6(c), respectively. If the gains are calibrated so that the magnitudes of these signals match at their peaks, and the difference signal between them is determined, the signal shown in FIG. 6(d) will be obtained. The magnitude of the difference signal corresponds to the magnitude of color moiré that occurs in the color signal obtained using these signals.

Here, the output signal of the correction circuit shown by broken lines in FIGS. 6(b) and 6(c) is calculated by, for example, the following equation.

[0030]

[Math. 14]

If the W and G low frequency signals are obtained in addition to the low pass filter 7 and low pass filter 8 that perform the following, the waveforms shown by thin lines in FIGS. 6(b) and 6(c), respectively, are obtained. As a result, when the interpolation process of the configuration shown in FIG.
), and the W and G signals shown in (f) are obtained. Therefore, the difference signal is as shown in FIG. 6(g). Figure 6 (d
) and (g), the difference signal between the W signal and the G signal is significantly reduced by performing the interpolation process.

However, when comparing FIGS. 6(d) and (g) in detail, the difference signal when the interpolation process is performed is as follows: 2n・P
Between x, it is significantly smaller than before interpolation processing, whereas when
+1)・Px or higher causes slight deterioration.

[0033]

[Problems to be Solved by the Invention] The signal interpolation method of the prior art described above can significantly reduce false color signals generated at the edges of the object, but the magnitude of the high frequency components of the object There has been a problem in that the improvement effect is reduced when the low frequency component occupies a large proportion compared to the magnitude of the low frequency component.

[0034] The first object of the present invention is to eliminate false color signals generated at the edges of an object even when the magnitude of high frequency components of the object is large compared to the magnitude of low frequency components. The object of the present invention is to obtain a signal interpolation device that can be significantly reduced.

Furthermore, although the signal interpolation method of the prior art described above can significantly reduce false color signals in local areas of an object where the brightness changes sharply, there is a problem in that the signals deteriorate slightly in the peripheral areas. A second object of the present invention is to provide a signal interpolation device in which the effect of improving false color signals does not deteriorate even in the periphery of an object where brightness changes sharply.

[0036]

[Means for Solving the Problems] The first object is to provide an image sensor in which multiple types of color filters are repeatedly associated with a plurality of photoelectric conversion sections, and to limit the resolution of a subject provided in front of the image sensor. An optical filter and a first signal sequence corresponding to the color filter of the same type as the first signal obtained from any photoelectric conversion unit of the plurality of photoelectric conversion units are obtained from the output signal of the image sensor. a first sample means for extracting a second signal train having a different color filter corresponding to the first signal train from the output signal of the image sensor; a first conversion means for converting the output signal of the means; a second conversion means for converting the output signal of the second sample means; and a first conversion means for converting the output signal of the second sample means; a coefficient means for calculating a coefficient corresponding to the ratio with the output signal; a calculation means for performing an operation between the first signal and the output signal of the coefficient means; and an output signal of the second sample means. This is achieved by providing interpolation means for interpolating the output signal of the calculation means.

[0037] The second object is to combine a first signal arbitrarily selected from a signal source in which a plurality of signals having different relationships with the original signal are alternately extracted and arranged, and the original signal. a first sampling means for extracting from the signal source a first signal sequence having the same type of relationship with the first signal sequence; and a second sampling means for extracting a second signal sequence different in type from the first signal sequence from the signal source. a sampling means, a first converting means for converting the output signal of the first sampling means, a second converting means for converting the output signal of the second sampling means, and an output of the first converting means. a coefficient means for calculating a coefficient corresponding to the ratio of the signal to the output signal of the second conversion means; a calculation means for performing an operation between the first signal and the output signal of the coefficient means; a correction means for obtaining a first interpolated signal from a signal obtained around the first signal in the signal train; and a detection means for detecting a steep change in the original signal around the first signal. means, switching means for switching and outputting the output signal of the calculation means and the output signal of the correction means according to the output signal of the detection means;
This is achieved by providing interpolation means for interpolating the output signal of the sampling means with the output signal of the switching means.

[0038]

[Operation] In the signal interpolation device according to the present invention, the optical filter provided in front of the image sensor, which combines multiple types of color filters, generates sideband components from among the spatial frequency components of the subject, and uses the above-mentioned coefficients. It operates to reduce components mixed into the band of a low-pass filter, which is a conversion means when determining . As a result, the ratio of the signals obtained from the low-pass filter has a value close to the ratio of the baseband components of the two signals, so interpolation using the output signal of the calculation means is sufficient to prevent false color signals. It is possible to obtain significant improvement effects.

Further, according to the present invention, when the detection means does not detect a sharp change in the subject around the first signal, the switching means detects the sharp change obtained around the first signal. Since interpolation is performed using the signal obtained from the second color signal sequence, the effect of the abrupt change does not extend to positions far away from the abrupt change in the subject.

[0040]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a signal interpolation device according to the present invention, FIG. 7 is a diagram showing frequency components of a signal obtained in the above embodiment, and FIG. 8 is a diagram showing the operation of an optical low-pass filter. 9 is a diagram showing the configuration of another embodiment of the present invention, FIG.
0 is a diagram showing an example of a signal waveform obtained in an embodiment of the present invention. As in the conventional example shown in FIG. 2, the color filter shown in FIG. 3 is combined with the image sensor 2 of the above embodiment. The difference between the above embodiment and the configuration of the conventional example shown in FIG. 2 is that an optical low-pass filter 12 is provided between the lens 1 and the image sensor 2. That is, the configuration of this embodiment is such that the subject image passing through the lens 1 reaches the image sensor 2 via the optical low-pass filter 12, and the output signal of the image sensor 2 is transmitted to the separation circuit 3 and the separation circuit 4.
For example, after separating into W and G pixel signals, the signals are passed through correction circuits 5 and 6 and then applied to low-pass filters 7 and 8 to extract their respective low frequency components. The output signals of the low-pass filters 7 and 8 are added to the dividing circuit 9, and the ratio of the low frequency component of the pixel signal W to the low frequency component of the resulting pixel signal G is calculated by the multiplying circuit 10 to the dividing circuit 9.
The above multiplication circuit 1 multiplies the pixel signal obtained from
The output signal of 0 is added to the W pixel signal obtained from the separation circuit 3 by the addition circuit 11 to obtain the W signal with the odd-order sideband components reduced. The optical low-pass filter 12 can be realized using, for example, a crystal plate whose thickness d corresponds to a target passband. That is, Fig. 8(a
) shows a cross-sectional view of the optical system in the optical path direction, the light that enters the crystal plate 15 from the lens (upper part of the figure, not shown) has an optical path that travels straight and an optical path that is refracted by an angle θ. The light is split into two optical paths, and from the crystal plate 15 becomes two parallel lights and heads towards the image sensor 2. As a result, a double image is formed on the imaging surface of the image sensor 2, the distance being shifted by d·tan θ.

At this time, if the function representing the change in brightness of the subject image in the horizontal direction is s(x), then the function o( x
) is the following formula.

[0042]

[Math. 15]

However, dx=d·tanθ. Therefore, if we set s(x)=exp(j2πf・x), o(
x) becomes as follows.

[0044]

[Math. 16]

In other words, the frequency components of the subject image are multiplied by the frequency characteristics expressed by cos(πf·dx) when they pass through the crystal plate, and as a result, the optical characteristics shown in FIG. 8(b) are obtained. A low-pass filter is realized.

Therefore, even if the frequency component of the subject has a high frequency component that is larger than the low frequency component, as shown in FIG. The frequency components of the image to be formed are those in which the high frequency components shown in FIG. 7(a) are suppressed. As a result, the frequency components of the W and G pixel signals separated by the separation circuits 3 and 4 are
), as shown in (c). As is clear from the comparison with the conventional example shown in FIGS. 5(b) and 5(c), FIG.
In b) and (c), within the band of the low-pass filters 7 and 8,
Sideband components mixed into the baseband component are sufficiently reduced. As a result, the signal obtained by adding the output signals of the low-pass filters 7 and 8 to the divider circuit 9 has a value close to the ratio of the W and G baseband components. Note that the low-pass filters 7 and 8 may separate the low frequency components of the input signal and then detect the power of the low frequency components, as in the case of the prior art.

FIG. 7(c) shows this by the multiplication circuit 10.
When multiplied by the separated G pixel signal shown in Figure 7 (
As shown in d), the output signal of the separation circuit 3 in FIG. 7(b) is a signal having a frequency component in which the magnitude of the baseband component is almost the same and the phase of the odd-numbered sideband component is opposite. can get. The above calculations include a method of directly multiplying the coefficients, a method of changing the coefficients, and then multiplying the coefficients. As a result,
The signal obtained by adding the output signal of the multiplication circuit 10 and the output signal of the separation circuit 3 by the addition circuit 11 is as follows.
As shown in FIG. 7(e), the odd-order sideband components are sufficiently reduced. Therefore, false color signals are suppressed from chroma signals obtained using these signals, and color moire on reproduced images can be removed.

Note that the optical low-pass filter using a quartz plate is used to reduce color moire due to its effect of reducing high frequency components of the subject. However, in the method using only a crystal plate, although high frequency components are reduced, sideband components mixed in the frequency band of the chroma signal remain as false color signals. Therefore, in order to obtain a sufficient effect of reducing color moiré, it is necessary to use a method to further reduce higher frequency components, such as using two crystal plates to separate triple images as shown in Figure 8(c). be. In the method of separating into triple images, the frequency components of the subject are
) are multiplied, color moiré is sufficiently reduced, but resolution is significantly degraded. In contrast, in the method of the present invention, the sideband components themselves are reduced by interpolation, so the sideband components mixed into the frequency band of the chroma signal can be sufficiently suppressed with just one crystal plate.
The effect of reducing false color signals is enormous.

On the other hand, an embodiment of the second object of the present invention will be explained with reference to the configuration diagram shown in FIG. The configuration diagram shown in FIG. 9 differs from the conventional configuration diagram shown in FIG. 2 in that the output signal of the multiplication circuit 10 is applied to the addition circuit 11 via the gate circuit 13. At this time, the output signal of the correction circuit 5 is applied to the other input of the gate circuit 13. The operation of the correction circuit 5 is similar to that of the prior art configuration shown in FIG. Furthermore, the gate circuit 13 is controlled by the output signal of a detection circuit 14 that detects a sudden change in the brightness of the subject from the output signal of the image sensor 2.

Here, an example of the operation of the detection circuit 14 is shown in FIG.
) at x=(2n-1)・Px, the pixel signal G0 and the pixel signal G− obtained at x=(2n-3)・Px
1, and the pixel signal G0 and x=(2n+
1) Difference signal D2 with pixel signal G+1 obtained at Px,
Then, calculate the difference signal D3 between the pixel signal W-1 obtained at x=(2n-2)・Px and the pixel signal W+1 obtained at x=2n・Px shown in FIG. 6(b), and A determination signal is output to determine whether any of them is larger than a separately determined boundary value. To give an example of the boundary value at this time,
The boundary value to be compared with the difference signal D1 or D2 is a fraction (for example, 1/2) of the maximum value of the pixel signals G0, G-1, G+1, and the boundary value to be compared with the difference signal D3 is the pixel signal. A value such as a fraction of the maximum value of W-1 and W+1 may be selected so that if the difference signal exceeds that value, a change in the subject is obvious.

When the output signal obtained from the detection circuit 14 in this manner indicates a sharp change in the brightness of the subject, the gate circuit 13 sends the output signal of the multiplication circuit 10 to the addition circuit 11 to detect the subject. When the brightness does not show a sharp change, the gate circuit 13 sends the output signal of the correction circuit 5 to the addition circuit 11. As a result, when the operation of the detection circuit 14 is as described above, the gate circuit 1
From 3, x=(2n-2)・Px or x=(2n+
1).In the range of Px, the output signal of the multiplication circuit 10 is obtained, and in the other range, the output signal of the correction circuit 5 is obtained. That is, from the gate circuit 13, x=(2n-2)・Px or x=(2n+1)・P
The G pixel signal shown in FIG. 6(e) is obtained in the x range, and the G pixel signal shown in FIG. 6(b) is obtained in the other range, so It becomes a signal. In addition, by applying similar processing to the pixel signal of W, the signal in FIG. 10(a) is obtained from the signals in FIGS.
The W pixel signals shown in are synthesized. As a result, the difference signal obtained by calibrating the magnitude of the two output signals is shown in Figure 10(c).
It will be as shown below.

Comparing FIGS. 6(d) and 6(g) with FIG. 10(c), it can be seen that according to the embodiment with the configuration shown in FIG. A difference signal is obtained which is significantly improved like the prior art method, but with a smaller difference signal at the periphery than the prior art method.

As described above, the present invention has been described using an example in which each color signal is obtained every pixel sampling period from the output signal of an image sensor in which two types of color signals are obtained alternately. It is possible to extend this method to the case where each signal is reproduced at each sampling period from a signal obtained by sampling and arranging three or more types of signals with large values in a fixed order.

Although the embodiments of the present invention have been described using hardware means as an example, it is clear that they can be similarly realized by software means by using a general-purpose computer or the like. It is.

[0055]

As described above, the signal interpolation device according to the present invention comprises an image sensor in which a plurality of photoelectric conversion sections are arranged in at least one dimension, and a plurality of types of color filters are repeatedly associated with the plurality of photoelectric conversion sections. and an optical filter provided in front of the image sensor to limit the resolution of the object, and the color filter of the same type as the first signal obtained from any photoelectric conversion unit among the plurality of photoelectric conversion units. a first sampling means for extracting a first signal sequence corresponding to the output signal of the image sensor from the output signal of the image sensor; a second sample means for extracting from the output signal of the first sample means; a first conversion means for converting the output signal of the first sample means; and a second conversion means for converting the output signal of the second sample means; coefficient means for calculating a coefficient corresponding to the ratio of the output signal of the first conversion means and the output signal of the second conversion means; and a calculation between the first signal and the output signal of the coefficient means. and an interpolation means that interpolates the output signal of the second sampling means with the output signal of the calculation means, so that the magnitude of the high frequency component of the subject can be compared with the magnitude of the low frequency component. Even when a large proportion of the image is captured, false color signals generated at the edges of the subject can be significantly reduced. Further, according to the signal interpolation device of the present invention, the effect of improving false color signals does not deteriorate even in the periphery of a subject where the brightness changes sharply.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a signal interpolation device according to the present invention.

FIG. 2 is a configuration diagram of a signal interpolation device according to the prior art.

FIG. 3 is a diagram showing an example of an arrangement of color filters.

FIG. 4 is a diagram showing an example of frequency components of a signal obtained by the conventional technique.

FIG. 5 is a diagram illustrating another example of frequency components of a signal obtained by the conventional technique.

FIG. 6 is a diagram showing an example of a signal waveform obtained by the conventional technique.

FIG. 7 is a diagram showing frequency components of a signal obtained in an embodiment of the present invention.

FIG. 8 is a diagram showing the operation of an optical low-pass filter.

FIG. 9 is a diagram showing the configuration of another embodiment of the signal interpolation device according to the present invention.

FIG. 10 is a diagram showing an example of a signal waveform obtained in the above embodiment.

[Explanation of symbols]

2 Image sensor 3, 4 Sample means (separation circuit) 5, 6
Correction means 7, 8 Conversion means (low-pass filter) 12
Optical low-pass filter 13 Switching means (gate circuit) 14
Detection means

Claims (5)

[Claims] 1. An image sensor comprising a plurality of photoelectric conversion sections arranged in at least one dimension, and a plurality of types of color filters repeatedly associated with the plurality of photoelectric conversion sections; The first signal sequence corresponding to the color filter of the same type as the first signal obtained from an optical filter that limits resolution and an arbitrary photoelectric conversion unit among the plurality of photoelectric conversion units is imaged. a first sample means for extracting from the output signal of the image pickup element; a second sample means for extracting from the output signal of the image sensor a second signal sequence corresponding to the first signal sequence and having a different color filter; a first conversion means for converting the output signal of the first sample means; a second conversion means for converting the output signal of the second sample means; a coefficient means for calculating a coefficient corresponding to a ratio of the output signal of the second conversion means; a calculation means for performing an operation between the first signal and the output signal of the coefficient means; and a second sampling means. and interpolation means for interpolating the output signal with the output signal of the arithmetic means. 2. A first signal arbitrarily selected from a signal source in which a plurality of types of signals having different relationships with the original signal are alternately taken out and arranged, and a first signal having the same type of relationship with the original signal. a first sampling means for extracting a signal sequence from the signal source; a second sampling means for extracting a second signal sequence different in type from the first signal sequence from the signal source;
a first conversion means for converting the output signal of the first sample means; a second conversion means for converting the output signal of the second sample means; a coefficient means for calculating a coefficient corresponding to the ratio of the output signal of the second conversion means; a calculation means for performing an operation between the first signal and the output signal of the coefficient means; From the signals obtained around my first signal,
correction means for obtaining a first interpolated signal; detection means for detecting a steep change in the original signal around the first signal;
switching means for switching and outputting the output signal of the calculation means and the output signal of the correction means according to the output signal of the detection means; and interpolation means for interpolating signals. 3. The first converting means and the second converting means are low-pass filters that output low frequency components of the input signal.
The signal interpolation device described. 4. The first converting means and the second converting means output a signal corresponding to the power of the low frequency component of the input signal. signal interpolator. 5. The signal interpolation device according to claim 1, wherein said calculation means multiplies the output signal of said coefficient means and said first signal.