JPH1169377A - Image information encoding device and device applying the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the data quantity of image information with simple constitution without executing up-sampling in an image information unit using a single CCD. SOLUTION: CCD 10 is a single CCD type and any one of color component in respective picture elements RGB is allocated to it. Since G has a strong correlation with the luminance signal, 1/2 of the whole picture elements is allocated to G. Then, 1/4 of the remaining picture elements is allocated to the R signal, and 1/4 is allocated to the B signal. A color separation circuit 12 separates the output signal of CCD 10 into the respective color components and a Y/C matrix circuit 16 converts it into the luminance signal Y and a color difference signal C. The luminance signal Y and the color difference signal C are encoded in a picture encoder 18 and they are written into a recording medium 20. The colors are separated in the color separation circuit 12 and up-sampling and an interpolation processing are not executed. Thus, data quantity is prevented from wastefully increasing and the final data quantity of picture information outputted from the picture encoder 18 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for encoding image information. In particular, the present invention relates to encoding of image information in which each pixel constituting the image information has only information of a single color component, and relates to an application technique of the encoding.

[0002]

2. Description of the Related Art Devices for digitizing image information, such as digital video cameras and digital still cameras, are widely used. By the way, when the image information is expressed in color, red, green, and blue (R, G,
Information on color components such as B), cyan, magenta, and yellow (C, M, Y) is required. Therefore, a digital still camera or the like may include, for example, three CCDs corresponding to R, G, and B, for example. Then, the optical image is converted to a 3D image by a dichroic filter (prism) or the like.
A configuration in which color is separated into colors and the separated optical image is supplied to each CCD is widely adopted.

As described above, in the method using three CCDs, an RGB image can be captured by one exposure, and a good image can be obtained. However, the use of expensive spectral prisms tends to increase the price. Further, a space for accommodating the prism is required, so that the size becomes large, and a back focus is required to some extent.

Therefore, the method using three CCDs as described above is used only for a relatively high-end camera, and a single-chip type described below is often used for a low-cost camera for consumer use.

[0005] In this single-panel camera, only one CCD is used, and one pixel in this one CCD detects red (R) and another pixel has another color, for example, green (G). Is detected. That is, a CCD having a mosaic-like filter so as to respond to different colors for each pixel is used. This filter is a color filter array (Color Filter Arr).
ay: CFA). In this way, each pixel of the CCD is classified into three types: a pixel for detecting R, a pixel for detecting G, and a pixel for detecting blue (B).

Although a low-priced consumer camera employs a single-chip type using only one CCD as described above, this camera can only obtain a mosaic image. Therefore, in order to obtain a final RGB image,
I need to make up for missing color information.

That is, for example, only R information can be extracted from a pixel covered by an R filter.
Therefore, it is necessary to supplement the values of G and B in the pixel. The value of G or B to be supplemented is a pixel located around the pixel, and the value of G or B in the pixel for which the value of G or B is detected.
Or B by estimating the value. This signal processing is generally called “interpolation processing” or “upsampling”.

Such a color filter array (CF)
In the CCD having A), several patterns have been proposed as the CFA. In addition to the filter using the RGB filter, a complementary color C
Some use MY filters.

FIG. 7 is an explanatory diagram showing the state of some CFA patterns actually used.
The interpolation method differs for each of these patterns.
In FIG. 7, for example, the Bayer type (1) is widely used because it is advantageous in terms of resolution.

It should be noted that any of C in FIG. 7 (1) to (5)
Even in the case of using the FA, the data amount of the image information obtained by the CCD must be "padded" three times.
This is a matter of course because image information that should be originally obtained by three RGB CCDs is obtained by one CCD. FIG. 8 shows an example of a configuration block of a digital still camera using a single-chip CCD as described above.

As shown in FIG. 1, a conventional digital still camera comprises a CCD 10 for taking an image,
The image processing apparatus includes a color separation circuit 12 that separates an RGB image output from the CD 10 into respective color components, and a filter interpolation circuit 14 that performs “interpolation processing” on each of the separated color components. Each color component interpolated by the filter interpolation circuit 14 in this way has information for one screen of an image for each color component. The image signal subjected to the filter interpolation is converted into a luminance signal and a color difference signal in the Y / C matrix circuit 16. Then, the color difference signal and the luminance signal converted by the Y / C matrix circuit 16 are encoded by the image encoder 18, and the encoded image information is written to the recording medium 20. Although not abbreviated in FIG. 8,
Since the output signal of the CCD 10 is originally an analog signal, an A / D converter for converting the output signal into a digital signal is provided between the CCD 10 and the color separation circuit 12.

The operation of each element will be briefly described below.

The CCD 10 shown in FIG. 8 is the above-described single-plate color CCD, and has the Ba color shown in FIG.
This is a CCD having a yer-type CFA. This CCD1
FIG. 9 is an explanatory diagram showing how the output signal of 0 is color-separated in the color separation circuit 12. As shown in FIG. 9, the signal of each pixel composed of the three colors of R, G, and B is separated for each color component. As shown in this figure, one of the four pixels of the CCD 10 is assigned R, and two of the four pixels are assigned G. The remaining one pixel is assigned to B. It is empirically known that the number of pixels allocated to G is large because the value of the G color component has a high correlation with the luminance signal, and the luminance component has a greater effect on visual perception than the color component. Because there is.

[0014] The assignment of pixels to each color component varies depending on the configuration of the CFA. For example, as shown in (5) of FIG. 7, a CFA that allocates pixels equally to each of R, G, and B is also widely used.

Next, filter interpolation is performed by the filter interpolation circuit 14 on the signal color-separated by the color separation circuit 12. FIG. 1 is an explanatory diagram showing the state of this interpolation processing.
0 is shown. As shown in FIG. 10, for the R signal, for example, one signal is obtained for every four pixels. Therefore, there is no R signal value for three of the four pixels. Therefore, in the filter interpolation circuit 14, the value of the R signal is generated by interpolation for the pixel having no R signal. Various interpolation methods have been proposed. For example, the simplest way is to perform linear interpolation by linear operation. This is a method of obtaining a value by a linear operation from the value of the R signal around the pixel for which the value of the R signal is to be obtained. However, in general, an adaptive algorithm is often used to improve image quality. Interpolation processing is similarly performed on the G signal and the B signal, and a signal for one screen is obtained for each of the R, G, and B color components.

Here, the frequency band of the image information signal will be described. FIG. 11 is a graph showing the frequency band of the output signal of the color separation circuit 12. FIG. 11 (1)
Is the frequency band of the green (G) signal, and FIG.
Is a graph showing frequency bands of blue (B) and red (R) signals. In each graph, the vertical axis represents the vertical direction of the image, and the horizontal axis represents the signal in the horizontal direction.

Here, the graph shown in FIG.
The image signal shown on the left side of FIG. 10, that is, the frequency band of the output signal of the color separation circuit 12, but the image signal shown on the right side of FIG. 10, ie, the frequency band of the output signal of the filter interpolation circuit 14 But also. Strictly speaking, FIG.
As shown in (1) of FIG. 12, the signal shown on the left side of 0 has aliasing in a frequency band other than the frequency band determined from the sampling rate of the original pixel. On the other hand, by performing up-sampling at 1: 2 using the ideal low-pass filter, the frequency characteristic changes as shown in (2) of FIG. 12, and the spectrum becomes 0 in the adjacent frequency band. You can see that. Of course, this up-sampling means that sampling is performed at twice the rate with respect to the original pixel. Therefore, this (2) is aliased at twice the frequency as compared with the above (1). No change occurs in the frequency band of the image.

That is, in the example shown here,
The frequency characteristic of the signal of the image information does not change at all by the filter interpolation.

FIG. 12 is a graph showing the frequency band for the G (green) signal. In each of the graphs (1) and (2), the vertical axis represents the spatial frequency in the vertical direction and the horizontal axis represents the spatial frequency. The axis represents the spatial frequency in the horizontal direction. In this graph, the area indicated by oblique hatching means the frequency band of the original image. The area indicated by the dot is the frequency area of the aliasing noise.
As can be understood by comparing the graphs of (1) and (2), upsampling has an effect on aliasing noise, but has no effect on the frequency domain of the original image itself. There is no.

FIG. 12 is a graph showing the frequency band for the G (green) signal, but R (red) B
A similar graph for the frequency band for the (blue) signal is shown in FIG. The vertical axis of the graph in FIG. 13 has the same meaning as the horizontal axis in FIG. In addition, the meaning of the area indicated by hatching with oblique lines and the area indicated by dots are the same as those in FIG. Similar to FIG. 12, (1) and (2) in the graph of FIG. 13 are graphs showing the frequency domain before (1) and (2) after up-sampling, respectively. In FIG. 13 as well, upsampling affects only the return noise, and has no effect on the frequency domain of the original image itself.

Next, as shown in the block diagram of FIG. 8, the Y / C matrix circuit 16 converts the RGB signals into a luminance signal and a color difference signal. FIG. 14 is an explanatory diagram showing the conversion into the luminance signal and the color difference signal. As shown in this figure, a luminance signal Y and color difference signals Cb and Cr are obtained from the R, G and B color signals. Specifically, the luminance signal and the color difference signal are obtained by the following equations.

[0022]

## EQU1 ## Y = 0.30R + 0.59G + 0.11B Cb = BY Cr = RY In this way, the luminance signal Y and the color difference signals Cb, Cr
Is required. In this way, even when the code compression ratio of an image is increased by converting the image into a luminance signal and a color difference signal,
Color noise can be kept low, and conversion to NTSC signals becomes easy.

The luminance signal and color difference signal obtained by the Y / C matrix circuit 16 are encoded by an image encoder 18. As an encoding method (compression method) in the image encoder 18, for example, the JPEG method is widely used. In the example shown in FIG. 8, since the digital still camera is used, an image coding method for a still image is employed. However, a digital video camera or the like employs an MPEG method for a moving image, for example. The encoded image data is finally stored on the recording medium 2
Written to 0. As the recording medium 20, a recording medium such as a flash memory card is used in addition to a floppy disk, a hard disk, a magneto-optical disk, a phase change optical disk, and the like.

FIG. 15 is a block diagram showing the configuration of a conventional digital still camera of a different type from that of FIG. 8 and a device for reproducing a captured image.

The digital still camera shown in this figure has almost the same configuration as that of FIG.
A CD 10 and an A / D converter 22 are provided. An up-sampling circuit 24 corresponding to the filter interpolation circuit 14 shown in FIG. 8 is provided. By this up-sampling circuit 24, image information is transferred to three CCDs.
Is increased to the same data amount (bit amount) as obtained from.

The image encoder 18 comprises an image encoder 28 and a downsampling circuit 26 in FIG. Here, the configuration of FIG. 15 differs from that of FIG. 8 in that the image encoder 18 has a downsampling circuit 26 before the image encoder 28.
In FIG. 8, the image encoder 18 has only the function of data compression. However, in FIG. 15, in order to further reduce the final data amount (the data amount after compression), The downsampling circuit 26 is provided before the compression circuit 28.

The point that the image information after the data compression is written to the recording medium 20 is the same as the configuration of FIG. The image information written on the recording medium 20 is displayed on a monitor 36 by a reproducing device, for example. Although the monitor 36 is shown in the figure, a printing unit such as a video printer may be connected to this part.

Further, the reproducing apparatus includes an image decoder 30 for expanding the compressed image information. Further, the configuration shown in FIG. 15 has an up-sampling circuit 32 corresponding to the down-sampling circuit 26 for enlarging the image information and returning it to a normal size. The normal size image information is converted to an analog signal via a D / A converter 34 and then supplied to a monitor 36.

In an image processing apparatus using a single-chip type CCD, such as a conventional digital still camera, the amount of information is once apparently increased by filter interpolation, and then image coding is performed. This provides many image encoders on the premise that the R, G, and B signals of all the pixels constituting the image are aligned, and that the luminance signal Y and the color difference signals Cb and Cr are aligned. Because it is.

However, as shown in FIG. 9, the information of three colors R, G, and B is originally obtained from one CCD, so that the amount of information originally contained in the image information is small. Therefore, the substantial information amount is considerably smaller than the image information of one regular screen.

Therefore, if the image encoder is applied after increasing the data for one screen by filter interpolation,
It is expected that the data amount of the encoded image information will be considerably larger than the substantial information amount of the original image. This is because image coding was performed after apparently increasing the number of bits by filter interpolation for data originally having a small amount of information.

Therefore, an object of the present invention is to directly apply a signal of each color component after color separation to an image encoder without performing filter interpolation (also referred to as upsampling) and compress the signal by the image encoder. It is an object of the present invention to provide an image encoding device capable of reducing the size of data.

In the digital still camera having the structure shown in FIG. 15, as is apparent from FIG. 15, an up-sampling circuit 24 and a down-sampling circuit 26 are connected in series. However, there is a waste in the circuit configuration. Up-sampling and down-sampling are clearly the opposite signal processing. Even if the reverse processing is continuously applied to image information, the original image information does not substantially change, and can be said to be useless processing.

Therefore, another object of the present invention is to provide an image information coding apparatus in which the reverse signal processing connected in series is omitted and the amount of hardware is reduced.

[0035]

According to the present invention, there is provided an image information encoding apparatus for encoding the image information in which each pixel of the image information includes color component information. Means.

That is, there are provided a supply unit that supplies the image information to the image encoding unit without upsampling, and the image encoding unit that encodes the image information supplied by the supply unit. It is a thing.

A feature of the present invention is that upsampling is not performed. By not upsampling, the amount of information after encoding can be reduced.

The color component is preferably a single color component.

According to the present invention, there is provided an image information encoding apparatus for encoding the image information in which each pixel of the image information includes color component information, wherein each pixel of the image information is separated for each color component. A color separating unit, a supplying unit that supplies information of a color component of each pixel separated by the color separating unit to the image encoding unit without upsampling, and a color separating unit that separates color components of the pixel separated by the color separating unit. An image encoding unit that encodes the image information based on information.

The present invention is different from the above-mentioned invention in that a color separation means is provided. Because it has color separation means,
Encoding can be performed for each color component.

The color component is preferably a single color component.

Further, according to the present invention, in an image information encoding apparatus for encoding the image information in which each pixel of the image information contains information of a color component, each pixel of the image information is separated for each color component. A color separation unit that supplies the information of the color components of each pixel separated by the color separation unit to the luminance / color difference conversion unit without upsampling; An image information encoding apparatus, comprising: a luminance / chrominance conversion unit for converting into a color difference signal; and an image encoding unit for encoding the luminance / color difference signal.

The present invention is different from the above-mentioned invention in that a luminance / color difference conversion means is provided. Since the luminance / color difference conversion means is provided, it is possible to perform image compression code Kato processing on a more compressed signal.

The color component is preferably a single color component.

According to another aspect of the present invention, there is provided an image pickup means for outputting the image information in which each pixel of the image information contains information of a color component. And a supply unit that supplies the supplied image information as it is to the image encoding unit, and the image encoding unit that encodes the supplied image information without downsampling.

Since upsampling and downsampling are not performed, a device similar to the conventional device can be configured with a simple configuration.

Further, the present invention is characterized in that the image information is image information obtained from a single CCD.

Since a single CCD can extract color component information from each pixel, it is possible to easily output image information having the above properties.

The color component is preferably a single color component.

Further, as the present invention having the same function, there is also a device using a single-chip CCD as the imaging means.

Further, the present invention includes the above-mentioned image information encoding device, and recording means for recording the image information encoded by the image information encoding device on a recording medium.

Thus, smaller data is recorded on the recording medium.

Further, the present invention includes the above-described image photographing apparatus and recording means for recording the image information encoded by the image information encoding apparatus on a recording medium.

Thus, smaller photographing data is recorded on the recording medium.

Also, the present invention provides a decoding means for decoding information encoded by the image information encoding device,
Interpolation means for performing an interpolation process on each color component of the image information decoded by the decoding means and converting the data of each color component into data of all pixels.

When the image information is encoded, the information is not interpolated (up-sampling). Therefore, by interpolating (up-sampling) on the decoding side, data for the entire screen is obtained.

Further, the present invention provides a decoding means for decoding information encoded by the image photographing apparatus, and an interpolation process for each color component of the image information decoded by the decoding means. Interpolating means for converting the data of each color component into data for all pixels.

In the present invention, since the upsampling is not performed on the photographing side, interpolation (upsampling) is performed on the decoding side.

Further, the present invention, in the above-mentioned image information decoding apparatus, includes RGB conversion means for converting data of all pixels interpolated by the interpolation means into RGB signals.

Since the RGB signal is converted, the signal can be output to a device that can handle the RGB signal, such as a display device.

Further, the present invention provides a decoding means for decoding the image information encoded by the image information encoding apparatus, and an image decoding means for decoding the image information decoded by the decoding means by RG.
It includes an RGB conversion means for converting into a B signal, and an interpolation means for performing an interpolation process on each color component of the RGB signal converted by the RGB conversion means to obtain RGB signals for all pixels.

This invention also has RGB conversion means as in the above-mentioned invention, but the RGB conversion means is provided not before the interpolation means but before the interpolation means. In other words, the interpolation means may be essentially before or after the conversion to the RGB signal.

The present invention also provides decoding means for decoding the image information encoded by the image photographing device, RGB conversion means for converting the image information decoded by the decoding means into RGB signals, Interpolation means for performing interpolation processing on each color component of the RGB signal converted by the RGB conversion means to obtain RGB signals for all pixels.

The point that the image information encoded by the photographing device is decoded is different from that of the above-mentioned invention. However, the point that the RGB conversion means is provided before the interpolation means is the same as that of the above-mentioned invention. Have

According to the present invention, there is provided an image information reproducing apparatus for reproducing image information from a recording medium on which image information is recorded by the image information recording apparatus, wherein reading means for reading encoded image information from the recording medium comprises: A decoding means for decoding the image information read by the reading means, and an interpolation process for each color component of the image information decoded by the decoding means, and the data of each color component Interpolating means for converting the data into pixel data.

Also in the present invention, since the reproduction side is provided with the interpolation means, it is possible to obtain data for the entire screen and reproduce the image.

Further, the present invention, in the above-mentioned image information reproducing apparatus, includes RGB conversion means for converting data of all pixels interpolated by the interpolation means into RGB signals.

Since the image data is converted into an RGB signal, image information can be output to a device capable of inputting the RGB signal.

Further, the present invention employs the following means in an image information reproducing apparatus for reproducing image information from a recording medium on which image information has been recorded by the image information recording apparatus.

That is, reading means for reading the image information encoded from the recording medium, decoding means for decoding the image information read by the reading means, and decoding means for decoding the image information read by the reading means. RGB conversion means for converting image information into RGB signals;
Interpolation means for performing interpolation processing on the RGB signals obtained by the B conversion means and converting data of each color component into data for all pixels.

According to the present invention, the RGB conversion means is provided with the RGB conversion means before the interpolation means.

Further, the present invention, in the above-mentioned image information reproducing apparatus, includes display means for displaying the image information. The display means can display the reproduced image.

Further, the present invention, in the above-mentioned image information reproducing apparatus, includes a printing means for printing the image information. With this printing means, it is possible to print the reproduced image.

[0074]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a block diagram showing a configuration of an apparatus according to the present embodiment for photographing an image with a digital signal and storing the photographed digital image in a recording medium. This configuration block diagram is a configuration block diagram showing a configuration of a digital still camera or a digital video camera, for example. As can be understood by comparing this configuration block diagram with the configuration block diagram of the conventional digital still camera shown in FIG. 8, in the present embodiment, filter interpolation is performed on the R, G, and B signals. Is not provided. As a result, each signal color-separated in the color separation circuit 12 is directly supplied to the Y / C matrix circuit 16.

As described above, a characteristic of this embodiment is that no filter interpolation is performed. By not performing the filter interpolation, the image information of one CCD output from the CCD 10 is supplied to the Y / C matrix circuit 16 and the image encoder 18 as it is. As a result, the amount of image information finally output from the image encoder 18 is also small, and more image information can be stored in the recording medium 20 having the same capacity.

The feature of the present embodiment is that the filter interpolation circuit 14 is not provided, and the other configuration is basically the same as that of the conventional digital still camera.

The CCD 10 is also a single-chip CCD in this embodiment, and its CFA is a Bayer type as shown in FIG. 7A. An output signal of the CCD 10 is supplied to a color separation circuit 12 and separated into R, G, and B signals. The output signal of the color separation circuit 12 is exactly the same as the output signal of the color separation circuit 12 in the conventional digital still camera.

In this embodiment, the color separation circuit 1
2 are directly supplied to the Y / C matrix circuit 16 without performing filter interpolation. FIG. 2 shows how the Y / C matrix circuit 16 generates the luminance signal Y and the color difference signals Cb and Cr.

The explanatory diagram shown in FIG. 2 shows how the R, G, and B signals are converted into a luminance signal Y and a color difference signal CrCb, and corresponds to the diagram of FIG. 14 in the prior art. It is. As can be understood by comparing FIG. 2 which is an explanatory diagram in the present embodiment with FIG. 14 in the related art, as the supplied RGB signals, data that has been skipped between filters without filter interpolation is obtained. Supplied. Then, the obtained luminance signal Y and color difference signals Cr and Cb are also obtained (as shown in FIG. 2).
It is a discrete data signal that has been skipped. That is, for a certain pixel, only the luminance signal Y exists, and the color difference signals Cr and Cb do not exist. In another certain pixel, only the color difference signal Cr exists, and the luminance signal Y and other color difference signals do not exist. As a result, as can be understood by comparing FIG. 2 and FIG. 14, the data amounts of the obtained luminance signal and color difference signal are significantly reduced as compared with the conventional technology.

A method of calculating the luminance signal Y and the color difference signals Cr and Cb from the intermittent RGB signals in this embodiment will be described below.

The conversion from the RGB signals to the luminance signal Y and the color difference signals Cr and Cb is performed in units of four pixels as shown in FIG. These four pixels are performed on four pixels in a cross shape surrounded by a thick line in FIG. The four pixels are two pixels to which the G signal is assigned and one pixel each to which the R signal and the B signal are assigned, for a total of four pixels. The G signal is assigned to two pixels, one of which is called G0 and the other is called G1. As shown in FIG.
1, R and B are composed of luminance signals Y0, Y1, Cr and Cb.
It is converted into a cross shape of pixels. Next, a specific calculation formula will be described.

[0083]

[Mathematical formula-see original document] Luminance Y0 = 0.30R + 0.59G0 + 0.11B Luminance Y1 = 0.30R + 0.59G1 + 0.11B Color difference Cb = B- (Y1 + Y0) / 2 Color difference Cr = R- (Y1 + Y0) / 2.

In this embodiment, the CF of the CCD 10 is
Since the Bayer type as shown in FIG. 7A is adopted as A, the above-described calculation formula is used. However, even when other CFA is used, almost the same calculation formula can be applied.

In the prior art, as shown in FIG. 14, the data in which the number of pixels is apparently increased after filter interpolation is converted into luminance and chrominance. This is information, and the frequency band included in the image is not expanded when filter interpolation is performed. Therefore, in the present embodiment, the CCD 1
Using the image information output from 0 as it is, conversion into a luminance signal and a color difference signal is performed. As a result, the data amount of the obtained luminance signal and color difference signal can be reduced, but the quality of the finally obtained image is not affected at all.

Although the luminance signal and the color difference signal as shown in FIG. 14 of the prior art are larger in data amount (bit amount) than the data shown in FIG. As a result, the frequency band of the image signal contained therein is not widened at all. Therefore, since the data can be coded (compressed) into a small data amount (bit amount) as in the present embodiment, the quality of the image obtained in the present embodiment is the same as that of the conventional image. .

The luminance signal Y and the color difference signals Cr and Cb obtained by the processing as shown in FIG. 2 are supplied to the image encoder 18 shown in FIG.
The image is encoded by the EG1 method, the MPEG2 method (or various methods based on these methods), or the like. The encoded data has a smaller data amount than the output signal of the image encoder 18 by a conventional digital still camera, digital video camera, or the like.
Even for 0, more image information can be stored than before.

In the above embodiment, as shown in FIG. 2, the conversion from the RGB signal to the luminance signal Y and the color difference signals Cr and Cb is performed for each of the four cross-shaped pixels.

However, since the positions of the pixels to which R and B are assigned are different from the positions of the pixels to which G is assigned, color misregistration is likely to occur. Therefore,
It is conceivable to prevent color misregistration by reproducing the B signal and the R signal corresponding to the positions of the pixels G0 and G1 in FIG. FIG. 3 is an explanatory diagram of this calculation method. As shown in FIG. 3, the value of the B signal at the position G0 is obtained, for example, by taking an average value of B and B0 shown in FIG. That is, the simplest linear interpolation is performed. Similarly, the value of the R signal at the position of G0 can be obtained by calculating (R + R0) / 2. Similarly, the value of the B signal at G1 is (B + B1) /
2 and the R signal would be determined by calculating (R + R1) / 2 respectively.

In the example described above, the values of the B signal and the R signal corresponding to G0 and G1 are calculated with reference to only two pixels. However, the values of more neighboring pixels are referred to. It is also preferable to calculate by calculation.

Further, in the present embodiment, a Bayer type filter having a so-called checkerboard pattern has been described. However, linear interpolation is similarly performed with other filters ((2) to (5) in FIG. 7). By doing so, it is possible to obtain the values of the B signal and the R signal at the position of G. However, G, B, and R corresponding to two G in four pixels
Is limited to the case where one pixel corresponding to each exists.

The configuration of an apparatus for reproducing an image recorded by a digital still camera or a digital video camera according to the present embodiment is also shown in the block diagram of FIG.

The image decoder 40 is a decoder that performs the reverse operation of the image encoder 18.
Are the same as the output signals of the Y / C matrix circuit 16, and are composed of a luminance signal and a color difference signal.

The output signal of the image decoder 40 is supplied to an RGB conversion circuit 42, which converts a luminance signal and a color difference signal into RGB signals. At this time, this R
(Y, Cb, Cr) to (R, G, B) from (Y, Cb, Cr) so that the output signal of the GB conversion circuit 42 is the same as the output signal of the color separation circuit 12, that is, so that color shift does not occur. Perform the conversion.

A characteristic configuration of the reproducing apparatus according to the present embodiment is an upsampling circuit 32. This is because the output signal of the RGB conversion circuit 42 has only one type of color component per pixel as described above. Therefore, it is necessary to increase the number of pixels to one regular screen by performing interpolation in the same manner as shown in FIG. 10 of the related art. The upsampling circuit 32 performs the same operation as the conventional filter interpolation circuit 14.

Therefore, it can be considered that the principle of the present invention is that the filter interpolation circuit 14 is moved from the camera side to the reproducing apparatus side.

The output signal of the upsampling circuit 32 is supplied to a monitor 36, where an image is displayed. Of course, it is also preferable to replace the monitor 36 with a printing device as described in the related art.

Also, as shown in FIG.
A configuration in which the conversion circuit 42 and the upsampling circuit 32 are interchanged may be used. In this case, since Y, Cb, and Cr data are obtained in all the pixels after the up-sampling, there is no need to pay particular attention to the color shift when the data is converted into R, G, and B. Also, in FIGS. 1 and 4, in the case of a monitor of (Y, Cb, Cr) input, the R, G, B conversion can be omitted.

Embodiment 2 In the first embodiment, the RGB signal which is the output signal of the color separation circuit 12 is Y / C
After being converted into a luminance signal and a color difference signal in a matrix circuit 16, the signals are supplied to an image encoder 18.

However, for example, the image encoding performed by the image encoder 18 is based on the JPEG system, MPEG1,
In the case of the EG2 method (other methods based on these methods), the RGB signals can be encoded in the same manner as the luminance / color difference signals, so that the output of the color separation circuit 12 is directly passed without passing through the Y / C matrix circuit 16. It is also preferable to supply the signal to the image encoder 18. FIG. 5 is a block diagram showing a configuration in which the Y / C matrix circuit 16 is omitted.

As shown in FIG. 5, the color separation circuit 1
The RGB signal, which is the output signal of the second image signal, is directly transmitted to the image
Is supplied to For example, when the image encoder 18 employs the JPEG method or the like, the Y / C matrix circuit 16 is omitted and the configuration as shown in FIG. 5 is used to reduce the amount of hardware or simplify the software. Can be realized.

FIG. 5 also shows the structure of a reproducing apparatus for reproducing an image. However, the other points are exactly the same as those of the reproducing apparatus of FIG. 1 except that the RGB conversion circuit 42 is not provided. is there.

Embodiment 3 As described above, the up-sampling circuit 24 and the down-sampling circuit 2 in the conventional digital still camera shown in FIG.
6 are connected in series. Since the operations of these circuits are reversed, omitting both of these circuits does not substantially affect the operation of the entire system.

Therefore, in the third embodiment, the up-sampling circuit 24 and the down-sampling circuit 26
1 shows a digital still camera or a digital video camera, in which "o" is omitted. FIG. 6 is a block diagram showing the configuration of a digital still camera having such a configuration. As can be understood by comparing FIG. 15 with FIG. 15, in the present embodiment, the up-sampling circuit 24 and the down-sampling circuit 26 are omitted, and
The output signal of the D converter 22 is directly converted into a data compression circuit 28
To supply.

With this configuration, the amount of hardware can be reduced, and unnecessary signal processing is not performed. Therefore, noise or distortion may be generated in the signal of image information. Absent.

In the present embodiment, the recording medium 20
Since no change has been made to the image information recorded in the conventional device, the same playback device as that used in the related art can be used.

[0107]

As described above, according to the present invention, it is possible to encode image information with a simple configuration and to reduce the data amount of the encoded image information.

Further, according to the present invention, it is possible to efficiently reduce the data amount of image information for each color component.

Further, according to the present invention, since the conversion into the luminance signal and the color difference signal is performed, the image signal can be further compressed.

Further, according to the present invention, since up-sampling and down-sampling are not performed, the image information can be encoded with a simple configuration and the data amount of the encoded image information can be reduced. Is obtained.

Further, according to the present invention, it is possible to efficiently encode image information output from a single CCD.

Further, according to the present invention, since image information having a reduced data amount is recorded on a recording medium, it is possible to store more image information even on a recording medium having the same capacity.

Further, according to the present invention, it is possible to obtain an image photographing / recording apparatus capable of storing more image information even on a recording medium having the same capacity.

Further, according to the present invention, there is provided an image information decoding apparatus for efficiently decoding image information encoded by the image information encoding apparatus according to the present invention.

Further, according to the present invention, there is provided an image information decoding apparatus for efficiently decoding image information encoded by the image photographing apparatus according to the present invention.

Further, according to the present invention, since the signal is converted into an RGB signal, a signal useful for a device that handles the RGB signal can be obtained.

Further, according to the present invention, a signal which is encoded by the image photographing apparatus is converted into an RGB signal, so that a signal useful for a device which handles the RGB signal can be obtained.

Further, according to the present invention, there is provided an image information reproducing apparatus capable of efficiently reproducing image information recorded by the image information recording apparatus according to the present invention.

Further, according to the present invention, the interpolated signal is represented by R
Since the signal is converted into the GB signal, a signal useful for a device that handles the RGB signal can be obtained.

Further, according to the present invention, since the interpolation processing is performed after converting into RGB signals, an image information reproducing apparatus capable of efficiently performing the interpolation processing for each color component is obtained.

Further, since a display means for displaying image information is provided, reproduced image information can be displayed.

Further, since there is a printing means for printing the obtained image information, it is possible to print the reproduced image information.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a digital still camera according to the present embodiment.

FIG. 2 shows a luminance signal Y and color difference signals Cr and C from RGB signals in a Y / C matrix circuit according to the present embodiment.
It is explanatory drawing showing the mode that b is obtained.

FIG. 3 is an explanatory diagram showing a state of linear interpolation when obtaining a B signal or an R signal at a position of a G pixel.

4 is a configuration block diagram illustrating a configuration in which positions of an RGB conversion circuit and an upsampling circuit are exchanged with the configuration illustrated in FIG. 1;

FIG. 5 is a configuration block diagram illustrating a configuration of a digital still camera according to the present embodiment.

FIG. 6 is a configuration block diagram illustrating a configuration of a digital still camera according to the present embodiment.

FIG. 7 is an explanatory diagram showing an example of a CFA (color filter array) of a single-plate CCD.

FIG. 8 is a configuration block diagram illustrating a configuration of a conventional digital still camera.

FIG. 9 is an explanatory diagram illustrating an operation of a color separation circuit in a conventional digital still camera.

FIG. 10 is an explanatory diagram illustrating an operation of a filter interpolation circuit in a conventional digital still camera.

FIG. 11 is a graph showing a frequency band of an output signal of the color separation circuit.

FIG. 12 is a graph showing a frequency band of an output signal of the color separation circuit.

FIG. 13 is a graph showing a frequency band of an output signal of the color separation circuit.

FIG. 14 is an explanatory diagram showing an operation of a Y / C matrix circuit of a conventional digital still camera.

FIG. 15 is a configuration block diagram illustrating a configuration of a conventional digital still camera.

[Explanation of symbols]

10 CCD, 12 color separation circuit, 14 filter interpolation circuit, 16 Y / C matrix circuit, 18 image encoder, 20 recording medium, 22 A / D converter, 2
4 Up-sampling circuit, 26 Down-sampling circuit, 28 image encoder, 30 Image decoder, 32
Upsampling circuit, 34 D / A converter,
36 monitor, 40 image decoder, 42 RGB conversion circuit.

Claims (18)

[Claims] 1. An image information encoding apparatus for encoding image information in which each pixel of the image information includes information of a color component, wherein the image information is supplied to an image encoding unit without upsampling. An image information encoding apparatus, comprising: a supplying unit that performs encoding and the image encoding unit that encodes the image information supplied by the supplying unit. 2. An image information encoding apparatus for encoding image information in which each pixel of the image information includes information of a color component, wherein a color separating unit separates each pixel of the image information for each color component. A supply unit that supplies the information of the color components of each pixel separated by the color separation unit to the image encoding unit without upsampling, based on the information of the color components of each pixel separated by the color separation unit, An image information encoding device, comprising: an image encoding unit that encodes the image information. 3. An image information encoding apparatus for encoding the image information in which each pixel of the image information includes information of a color component, wherein a color separating unit separates each pixel of the image information for each color component. Supply means for supplying information on the color components of each pixel separated by the color separation means to the luminance / color difference conversion means without up-sampling, and information on the color components of the separated pixels into a luminance / color difference signal. An image information encoding apparatus, comprising: a luminance / color difference conversion unit for converting; and an image encoding unit for encoding the luminance / color difference signal. 4. An image pickup unit for outputting the image information in which each pixel of the image information contains information of a color component; and a supply unit for supplying the image information to the image encoding unit without upsampling. An image encoding unit that encodes the supplied image information without downsampling. 5. The image information encoding apparatus according to claim 1, wherein the image information is image information obtained from a single-chip CCD. 6. An image photographing apparatus according to claim 4, wherein said image pickup means comprises a single CCD. 7. An image information encoding apparatus according to claim 1, 2, 3, or 5, and recording means for recording image information encoded by the image information encoding apparatus on a recording medium. Characteristic image information recording device. 8. An image photographing and recording apparatus comprising: the image photographing apparatus according to claim 4; and recording means for recording image information encoded by the image information encoding apparatus on a recording medium. apparatus. 9. A decoding means for decoding information encoded by the image information encoding apparatus according to claim 1, 2, 3 or 4 for each color component of the image information decoded by said decoding means. And an interpolation means for performing interpolation processing and converting data of each color component into data of all pixels. 10. A decoding means for decoding information encoded by the image photographing device according to claim 4, 6 or 8, interpolation for each color component of the image information decoded by said decoding means. Interpolating means for performing processing and converting the data of each color component into data for all pixels. 11. The image information decoding apparatus according to claim 9, wherein data of all pixels interpolated by said interpolating means is represented by R
An image information decoding apparatus, comprising: RGB conversion means for converting into a GB signal. 12. A decoding means for decoding image information encoded by the image information encoding device according to claim 1, 2, 3, or 8, further comprising: RGB conversion means for converting to RGB signals; and interpolation means for performing interpolation processing on each color component of the RGB signals converted by the RGB conversion means to obtain RGB signals for all pixels. Image information decoding device. 13. A decoding means for decoding image information encoded by the image photographing apparatus according to claim 4, 6 or 8, and RGB for converting the image information decoded by said decoding means into RGB signals. An image information decoding apparatus comprising: a conversion unit; and an interpolation unit that performs an interpolation process on each color component of the RGB signal converted by the RGB conversion unit to obtain RGB signals for all pixels. 14. An image information reproducing apparatus for reproducing image information from a recording medium on which image information has been recorded by the image information recording apparatus according to claim 7, wherein the encoded image information is read from the recording medium. Means, decoding means for decoding the image information read by the reading means, and interpolation processing on each color component of the image information decoded by the decoding means, data of each color component An image information reproducing apparatus, comprising: an interpolation unit that converts the data into data for all pixels. 15. The image information reproducing apparatus according to claim 14, wherein data of all pixels interpolated by said interpolating means is represented by R
An image information reproducing apparatus, comprising: RGB conversion means for converting into a GB signal. 16. An image information reproducing apparatus for reproducing image information from a recording medium on which image information has been recorded by the image information recording apparatus according to claim 7, wherein the encoded image information is read from the recording medium. Means, decoding means for decoding the image information read by the reading means, and the image information decoded by the decoding means
RGB conversion means for converting into RGB signals, and interpolation means for performing interpolation processing on the RGB signals obtained by the RGB conversion means and converting data of each color component into data for all pixels. Characteristic image information reproducing apparatus. 17. The image information reproducing apparatus according to claim 14, further comprising: display means for displaying said image information. 18. The image information reproducing apparatus according to claim 14, further comprising: a printing unit that prints the image information.