JP2003348609A - Signal processor and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a luminance signal with high quality by utilizing advantages of each of a plurality of luminance signal generating system. <P>SOLUTION: The signal processor (4) for processing an image signal obtained by imaging of an imaging device includes: an Out of Green luminance circuit (5) for generating a first luminance signal by the Out of Green system on the basis of a received image signal; a SwitchY luminance circuit (6) for generating a second luminance signal by the SwitchY system on the basis of the received image signal; a black/white color discrimination circuit (7) for discriminating whether the image signal indicates a black/white image or a color image on the basis of the received image signal; and a luminance mixing circuit (9) for mixing the first and second luminance signals depending on a result of discrimination by the black/white color discrimination circuit. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a signal processing apparatus, and more particularly to an apparatus for generating a luminance signal from an output signal from an image sensor having a plurality of color filters.

[0002]

2. Description of the Related Art Conventionally, as a method of creating a luminance signal based on an output color signal from a solid-state imaging device, a switchy method or an O method has been used.
The utofGreen method is known. Hereinafter, these systems will be described by taking as an example a case where the solid-state imaging device is covered with a color filter having a primary color Bayer array as shown in FIG.

In the SwitchY system, an output signal from a solid-state image sensor is A / D converted and then white balance (hereinafter, referred to as W).
B) In this method, the processed signal is regarded as the luminance signal Y as it is. FIG. 13 is a diagram showing the concept of the obtained luminance signal Y, and the number after Y indicates the position of a pixel. Also, in order to suppress the generation of carriers due to sampling, a low-pass filter (hereinafter referred to as L
The result of applying PF) to each of the horizontal and vertical directions is defined as a base signal. For example, assuming that the filter coefficient of the LPF is [1 2 1] in both the horizontal and vertical directions, the LPF of the Y22 pixel is
Y22 '= (Y11 + 2 × Y12 + Y13 + 2 × Y21 + 4 × Y22 + 2 × Y23 + Y31 + 2 × Y32 + Y33) / 16 (1)

[0004] It can be obtained as follows. Furthermore, a high-frequency-compensated signal can be obtained by generating a high-frequency emphasized signal from the base signal and adding the original base signal.

FIGS. 14A and 14B show the positions and bands of carriers in the frequency space. FIG. 14A shows a case where a monochrome image is taken, and FIG. 14B shows a case where a color image is taken. FIG. 14 (a)
In (b) and (b), fs indicates the sampling frequency.
In the case of the SwitchY method, when the subject is black and white, FIG.
This is advantageous because a carrier is generated at the position indicated by x and the band in the area surrounded by the solid line can be used.
However, when the subject is colored, FIG.
Since carriers are generated at positions indicated by crosses in FIG. 4B, the band is narrow as shown by the solid line in FIG. 14B, and aliasing occurs at a relatively low frequency, which is not preferable.

On the other hand, the OutofGreen system is a system in which each of red, green, and blue signals is independently processed, and in particular, a luminance is created around a green signal. For example, when processing a red signal, 0 is inserted into pixels other than red, and the above LPF is applied. The same processing is performed for the green signal and the blue signal, and the luminance Y is set to, for example,
It is determined using the following equation (2). Y = 0.3R + 0.59G + 0.11B ... (2)

Further, a high-frequency emphasized signal is created from only the green signal and added to Y. Since the OutofGreen method is a method of creating a luminance signal centering on a green signal, sampling is offset sampling, and in the case of a monochrome image, a carrier is generated at a position indicated by a circle in FIG. Therefore, the band of the area shown by the broken line can be used. Also, as shown in FIG. 14B, the same band can be secured for a color image as in the case of black and white, so that it can be used stably in both black and white and color. However, in the case of a black-and-white image, the oblique direction is narrower than the band of the SwitchY system, and there is a problem that jagging occurs due to reversal from the oblique direction.

[0008]

SUMMARY OF THE INVENTION As described above, the switch
In the Y method, it is strong for black-and-white subjects but weak for color subjects.In the OutofGreen method, it has a certain level regardless of black and white or color, but there is a problem that jaggies occur. In this case, an adverse effect occurs on the image.

The present invention has been made in view of the above problems, and has as its object to obtain a high quality luminance signal by making use of the advantages of each of a plurality of luminance signal generation methods.

[0010]

In order to achieve the above object, a signal processing apparatus of the present invention for processing an image signal obtained by capturing an image by an image sensor is provided based on an input image signal. A first luminance signal generating means for generating a first luminance signal according to the following; a second luminance signal generating means for generating a second luminance signal by a second method based on the input image signal; Determining means for determining whether the image signal indicates a black-and-white image or a color image based on the input image signal; and determining the first luminance signal and the second luminance signal in accordance with a determination result by the determining means. And mixing means for mixing the luminance signals.

A signal processing method for processing an image signal obtained by capturing an image by an image sensor includes a first luminance signal for generating a first luminance signal by a first method based on an input image signal. A generating step, a second luminance signal generating step of generating a second luminance signal by a second method based on the input image signal, and a step of generating a black-and-white image based on the input image signal. Or a color image, and a mixing step of mixing the first luminance signal and the second luminance signal according to the result of the determination in the determination step.

According to another aspect of the present invention, the signal processing device further includes a detecting unit that detects a portion of the image represented by the image signal, which indicates an oblique line, based on the input image signal. And the mixing unit mixes the first luminance signal and the second luminance signal according to a result of the determination by the determination unit and a result of the detection by the detection unit.
Further, the signal processing means further includes a detection step of detecting a portion indicating an oblique line in an image indicated by the image signal based on the input image signal, and in the mixing step, the determination result in the determination step And mixing the first luminance signal and the second luminance signal according to the detection result in the detection step.

According to another aspect of the present invention, a signal processing apparatus for processing an image signal obtained by imaging with an image sensor includes a first method based on an input image signal by a first method. First luminance signal generating means for generating a luminance signal of the second type, second luminance signal generating means for generating a second luminance signal by a second method based on the input image signal, and the input image Detecting means for detecting a portion indicating an oblique line in an image indicated by the image signal, based on the signal,
Mixing means for mixing the first luminance signal and the second luminance signal according to a detection result by the detection means.

[0014] A signal processing method for processing an image signal obtained by imaging by an image sensor includes a first luminance signal for generating a first luminance signal by a first method based on an input image signal. A generating step, a second luminance signal generating step of generating a second luminance signal by a second method based on the input image signal, and an image indicated by the image signal based on the input image signal The method includes a detecting step of detecting a portion indicating an oblique line therein, and a mixing step of mixing the first luminance signal and the second luminance signal according to a detection result in the detecting step.

[0015]

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

(First Embodiment) In the first embodiment, R (red), G (green), and B (blue) shown in FIG.
A case in which a luminance signal is obtained by using a signal from a single-chip image sensor covered with a color filter of a primary color Bayer array composed of colors will be described.

FIG. 1 is a block diagram showing a schematic configuration of an image pickup apparatus according to the first embodiment of the present invention. The imaging device is, for example, a digital still camera, a digital camera,
The present invention includes a scanner, a copier, and a facsimile, but is not limited thereto. The present invention can be applied to any device that acquires an incident optical image as an electrical image by photoelectric conversion.

In FIG. 1, reference numeral 1 denotes an image pickup device such as a CCD (hereinafter referred to as a CCD) which photoelectrically converts incident light and outputs an electric signal, 2 denotes an A / D conversion circuit, and 3 denotes a white balance (WB). The circuit 4 is a signal processing device. In the above configuration, a signal output from the CCD 1 is converted into a digital signal by the A / D conversion circuit 2, and a signal subjected to a known white balance process by the WB circuit 3 is input to the signal processing device 4.

The signal processing device 4 has an OutofGreen luminance circuit 5, a SwitchY luminance circuit 6, a black and white color discriminating circuit 7, an oblique line detection circuit 8, and a luminance mixing circuit 9. The OutofGreen luminance circuit 5 employs, for example, the OutofGreen method described in the related art, but may employ a method of switching the interpolation method adaptively to an image. The SwitchY luminance circuit 6 also employs, for example, the SwitchY method described in the related art. This Swic
The hY method is a method in which a red (R) signal, a green (G) signal, and a blue (B) signal are regarded as a luminance signal as they are, and in the case of an image sensor having a primary color Bayer array employed in the first embodiment. , The color composition ratio of luminance is R: G: B =
1: 2: 1.

Next, the operation of the signal processing device 4 having the above configuration will be described in detail with reference to FIGS.

FIG. 2 is a flowchart showing an outline of the processing in the signal processing device 4. In FIG. 2, the signal processing device 4 that has received the WB-processed signal from the WB circuit 3 (Step S11) creates a luminance signal 1 in the OutofGreen method in the OutofGreen luminance circuit 5 (Step S12). In the SwitchY luminance circuit 6, Swi
Create a luminance signal 2 by the tchY method (step S1)
3). Further, the black-and-white color discriminating circuit 8 discriminates whether the subject is monochrome or color, and generates a black-and-white color discriminating signal indicating the discrimination result (step S14). Then, an oblique line determination signal indicating the presence or absence of an oblique line is generated (step S1).
5). Then, the luminance mixing circuit 9 mixes the luminance signal 1 and the luminance signal 2 based on the black-and-white color determination signal and the oblique line determination signal (step S15). The order in which the processes of steps S12 to S14 are performed is not limited to the above, and may be performed in a different order, or a part or all of the processes may be performed simultaneously.

The black-and-white color discrimination process performed in step S13 will be described with reference to the flowchart of FIG. In the monochrome color discriminating circuit 7, first, in step S2
In step 1, the saturation signal C is calculated from the signal after white balance according to, for example, the following equation (3).

[0023]

Next, when the saturation signal C is smaller than the threshold value Th1 at a certain level (YE at step S22).
S), it is determined that the input signal indicates a black-and-white image, and 1 is set as the black-and-white color discrimination signal _DBC (step S2).
3). If the saturation signal C is equal to or larger than the threshold Th1 (NO in step S22), the comparison is made with a threshold Th2 larger than the threshold Th1 in step S24, and if the saturation signal C is larger than the threshold Th2 (YES in step S24). was determined to be a color image, 0 is set as the determination signal D _BC (step S25). If the saturation signal C is between the threshold value Th1 and the threshold value Th2 (NO in step S24), the determination signal D
_{The BC} is configured to take a numerical value between 1 and 0 linearly according to the distance from the thresholds Th1 and Th2 (step S26). Saturation signal C and threshold value Th1 in the above processing
And Th2, and those illustrated the relationship between the judgment signal D _BC is FIG.

In order to adjust the area for black-and-white color discrimination, for example, a maximum value filter of 3 × 3 is applied to the chroma signal C so that the discrimination area is enlarged or normalized by brightness. And a dark portion may be detected. The normalization by the brightness can be performed by, for example, dividing the saturation by the luminance Y.

Next, the oblique line detection process performed in step S14 of FIG. 2 will be described with reference to FIGS. FIG. 5 is a block diagram showing an example of the internal configuration of the oblique line detection circuit 8. The band-pass filter (BPF) A circuit 10, the BPFB circuit 11, and the low-pass filter (LPF) A use all the color signals after WB. Circuit 12, L
An area where jaggies occur is extracted by the PFB circuit 13.

As the band-pass filter, for example, a BPFA circuit 10 for applying a digital filter of [1−46−4−1] vertically and a digital filter of [−10 20 −1] horizontally, [1-46-4
1], and a BPFB circuit 11 that vertically applies a digital filter of [−100 0 −1]. As a low-pass filter, for example, the filter coefficient is horizontally set to [1
4 6 4 1] and vertically [1-2-2 2-2]
LPFA circuit 12 to which the digital filter of [1] is applied
[1 4 6 4 1] vertically and [1-2 horizontally]
LPF to which the digital filter of [2-2-1] is applied
The B circuit 13 is used.

The signal from the BPFA circuit 10 and the signal from the BPFB circuit 11 are converted into absolute values by the absolute value conversion circuit 14 and added by the adder 15 (step S31).
The addition signal S _BPF is compared with the threshold Th3, and when the addition signal S _BPF is smaller (YES in step S32).
It is determined that the line is not an oblique line, and 0 is set as the BPF detection signal _DBPF.
Is set (step S33). When the addition signal S _BPF is equal to or larger than the threshold Th3 (NO in step S32), the threshold T
The threshold value Th3 is compared with a threshold value Th4 which is larger than h3. Addition signal S
_{If BPF} is larger (YES in step S34)
It is determined as an oblique line, and 1 is set as the BPF detection signal _DBPF (step S35). The addition signal S _BPF is equal to the threshold Th3
And the threshold value Th4 (N in step S34)
O), the BPF detection signal D _BPF is equal to the threshold values Th3 and Th
It is set so as to take a numerical value between 0 and 1 linearly according to the distance from 4 (step S36). Addition signal S _BPF and threshold values Th3 and Th4 and BPF in the above processing
FIG. 7 illustrates the relationship with the detection signal _DBPF .

On the other hand, the purpose of the LPF circuit is to exclude low-frequency areas from areas detected as oblique lines by the BPF circuit. That is, since only the BPF circuit may detect an extra low frequency signal as an oblique line, the LPF circuit is configured to exclude the extra portion from the detection target.

The signal from the LPFA circuit 12 and the signal from the LPFB circuit 13 are converted to absolute values by the absolute value conversion circuit 14 and added by the adder 15 (step S37).
The addition signal S _LPF is compared with the threshold Th5, and when the addition signal S _LPF is smaller (YE in step S38).
S), it sets 1 as the LPF detection signal D _{LP F} so as not to remove from the slanting line detecting (step S39). When the addition signal S _LPF is equal to or smaller than the threshold Th6 (NO in step S38), the sum is compared with a threshold Th6 which is larger than the threshold Th5. If the addition signal S _LPF is larger (step S
If YES at 40), 0 is set as the LPF detection signal D _LPF to exclude from the oblique line detection target (step S41).
When the addition signal S _LPF is between the threshold value Th5 and the threshold value Th6, the LPF detection signal D _LPF becomes equal to the threshold values Th5 and T5.
It is set so as to take a numerical value between 0 and 1 linearly according to the distance from h6 (step S42). Addition signal S _LPF and threshold values Th5, Th6, and LP in the above processing
FIG. 8 illustrates the relationship with the F detection signal D _LPF .

In the example shown in FIG. 5, a configuration using a band-pass filter and a low-pass filter is shown. However, the present invention is not limited to this. For example, a high-pass filter may be used instead of the band-pass filter, or a low-pass filter may be used. , A band-pass filter or a high-pass filter may be used.

Next, the BPF detection signal _DBPF and LP
With F detection signal D _LPF, the result of taking the product by the multiplier 17, as the final slanting line detecting signal D _D (step S43).

In the oblique line detection circuit 8, the number of BPF circuits and LPF circuits may be increased in order to further increase the detection accuracy, and in order to adjust the detection area, a maximum value filter, normalization by brightness, and the like are performed. May be.

In FIG. 6, steps S37 to S37 are executed.
The processing of 42 may be performed before the processing of steps S31 to S36, or may be performed in parallel.

Next, the luminance signal mixing process performed in step S15 of FIG. 2 will be described with reference to the flowchart of FIG. In the luminance mixing circuit 9, the black-and-white color detection signal _DBC and the oblique line detection signal D
_The luminance signal 1 and the luminance signal 2 are mixed using _D.

[0036] Here, the input signal indicates a monochrome image, and discriminating portion to be oblique lines, that is, when white color determination signal D _BC and slanting line detecting signal D _D are both 1 (at step S51 YES), luminance signal 2 (Swit
chY method) is selected (step S52), and if it is another part (NO in step S51), the luminance signal 1 (Ou
tofGreen method) is selected (step S53). That is, only the part 2 in FIGS. 14A and 14B
Adopt chY luminance signal, other parts 1, 3, 4
Is configured to employ the OutofGreen signal. By doing so, it is possible to eliminate jaggies and to obtain a good signal without generating aliasing noise in a low frequency range even for a color subject.

As an example of the determination method performed in step S51, a black-and-white color determination signal D _BC and an oblique line detection signal D
It may be configured to take the product of _D and determine whether the obtained product is 1. In this case, if the obtained product is 1, the luminance signal 2 is selected, and otherwise, the luminance signal 1 is selected.

Further, so as to select the luminance signal 1 as a default, when a monochrome color determination signal D _BC and slanting line detecting signal D _D are both 1 (or product 1), to replace the luminance signal 2 You may comprise.

In addition to selecting either the luminance signal 1 or the luminance signal 2, the black-and-white color discriminating signal _DBC and / or
Or slanting line detecting signal D _D is a mixture of luminance signals 1 or 2 to indicate an intermediate value of 0 and 1, may be the final luminance signal and the lower. The luminance signal mixing process in that case will be described with reference to the flowchart of FIG.

If the input signal indicates a black-and-white image and is determined to be a diagonal line (eg, the product is 1 as described above) (YES in step S61), the luminance signal 2 is selected (step S61). In step S62), when the product becomes 0 (YES in step S63), the luminance signal 1 is selected (step S64), and when the product becomes a value α between 0 and 1 (NO in step S63), In order to make the switching smooth, the luminance signals 1 and 2 are mixed as shown in the following equation (4) (step S65). [Brightness] = α × [brightness signal 2] + (1-α) × [brightness signal 1] (4)

In the above example, the configuration in which the signal processing device 4 has both the black-and-white color discriminating circuit 7 and the oblique line detecting circuit 8 has been described. However, the signal processing device 4 may have only one of them. Specifically, when only the black-and-white color discriminating circuit 7 is provided, the luminance mixing circuit 9 performs the same processing as described above, except that in step S51 of the processing shown in FIG. In the process shown in FIG. 10, it is determined whether or not the monochrome color discrimination signal _DCB is 1 in step S61, and the monochrome color discrimination signal DBC is determined in step S63.
_BC will do the determination if it is 0, using the monochrome color determination signal D _BC step S65 as alpha. Otherwise, the same processing as above is performed.

On the other hand, when only the oblique line detection circuit 8 is provided, the luminance mixing circuit 9 performs step S5 of the processing shown in FIG.
The same processing as described above is performed except that it is determined in step 1 whether or not the line is an oblique line. In the processing shown in FIG.
Slanting line detecting signal D _D 61 performs Determining Whether 1,
Slanting line detecting signal D _D performs a 0 if the determined in step S63, the slanting line detecting signal D _D In step S65 alpha
Used as Otherwise, the same processing as above is performed.

As described above, according to the first embodiment, Ou
Using the tofGreen luminance circuit and the SwitchY luminance circuit, it is possible to obtain a luminance signal by utilizing only the respective advantages, and the aliasing signal that occurs in the oblique lines and the noise due to the folding of the color signal are generated. And a good luminance signal can be obtained.

(Second Embodiment) Next, a second embodiment will be described. FIG. 11 is a block diagram illustrating a configuration of an imaging device according to the second embodiment. Components similar to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. FIG.
, 24 is a signal processing device, 25 is an OutofGreen luminance circuit, 26 is a SwichY luminance circuit, 27 is a black-and-white color discriminating circuit, 28 is an oblique line detection circuit, and 29 is a luminance mixing circuit.
Is a high-frequency emphasis circuit. Except for the high-frequency emphasizing circuit 30, each circuit operates in the same manner as that shown in FIG. 1, and a detailed description thereof will be omitted here.

The OutofGreen luminance circuit 5 and the SwitchY luminance circuit 6 in the first embodiment each include a circuit (not shown) for adding a high-frequency emphasizing signal to a base signal, respectively. In the embodiment, the OutofGreen luminance circuit 25 and the SwitchY luminance circuit 26 do not include the high-frequency emphasizing circuit normally included, respectively, and have a configuration in which a common high-frequency emphasizing circuit 30 is provided instead.

The high-frequency emphasizing circuit 30 is provided after the luminance mixing circuit 29, and extracts a high-frequency signal by applying a band-pass filter to the luminance signal output from the luminance mixing circuit 29.
Add to the original luminance signal.

With this configuration, it is possible to reduce the number of high-frequency emphasizing circuits to one as compared with the first embodiment.

[0048]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a scanner, a video camera, etc.), an apparatus (for example, a digital Cameras, copiers, facsimile machines, etc.).

Further, an object of the present invention is to supply a storage medium (or a recording medium) on which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and to provide a computer (or a computer) of the system or apparatus. Or a CPU or MPU) reads out and executes the program code stored in the storage medium,
Needless to say, this is achieved. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.
In addition, by the computer executing the readout program code, not only the functions of the above-described embodiments are realized, but also based on the instructions of the program code,
The operating system (OS) running on the computer performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included. Here, as the storage medium for storing the program code, for example, a flexible disk, a hard disk, a ROM, a RAM, a magnetic tape, a nonvolatile memory card, a CD-ROM,
A DR, a DVD, an optical disk, a magneto-optical disk, an MO, and the like can be considered.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts shown in FIG. 2, FIG. 3, FIG. 6, and FIG. 9 or FIG. Will be.

[0052]

As described above, according to the present invention, since the advantages of each of the plurality of luminance signal generation methods can be utilized, a high-quality luminance signal can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an imaging device according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the overall operation of the signal processing device of FIG. 1;

FIG. 3 is a flowchart illustrating a black-and-white color discrimination processing operation according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a relationship between a black-and-white color discrimination signal and a saturation signal according to the first embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of an oblique line detection circuit in FIG. 1;

FIG. 6 is a flowchart illustrating an oblique line detection processing operation according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a relationship between an oblique line discrimination signal and a BPF output according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a relationship between an oblique line discrimination signal and an LPF output according to the first embodiment of the present invention.

FIG. 9 is a flowchart illustrating a luminance signal mixing processing operation according to the first embodiment of the present invention.

FIG. 10 is a flowchart illustrating another luminance signal mixing processing operation according to the first embodiment of the present invention.

FIG. 11 is a block diagram schematically illustrating a signal processing device according to a second embodiment of the present invention.

FIG. 12 is a diagram showing a primary color Bayer array.

FIG. 13 is an explanatory diagram of the SwitchY method.

FIG. 14 is a diagram illustrating a carrier generation position and a band in each method of generating a luminance signal.

[Explanation of symbols]

1 Imaging device (CCD) 2 A / D conversion circuit 3 WB circuit 4, 24 signal processing device 5, 25 OutofGreen luminance circuit 6,26 SwitchY luminance circuit 7,27 black and white color discrimination circuit 8,28 Oblique line detection circuit 9,29 Brightness mixing circuit 10 Bandpass filter A circuit 11 Bandpass filter B circuit 12 Low pass filter A circuit 13 Low-pass filter B circuit 14 Absolute value conversion circuit 15 Adder 16. Discrimination signal generation circuit 17 Multiplier 30 High frequency emphasis circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/64 H04N 1/46 CF term (Reference) 5C065 AA01 AA03 BB22 CC01 CC02 DD02 DD17 EE06 GG06 GG23 GG21 GG23 GG42 5C066 AA01 CA07 DA05 EC02 EC12 EE02 GA01 GA05 HA01 KC02 KC08 KC09 KD06 KD07 KD08 KE02 KE03 KM02 KM05 5C077 LL19 MM03 MP01 MP08 PP04 PP15 PP27 PP28 PP32 PQ08 PQ12 PQ22 NA04 LA01 MA01 HA13 LA01 PA02

Claims (41)

[Claims] 1. A signal processing device for processing an image signal obtained by imaging by an image sensor, comprising: a first method for generating a first luminance signal by a first method based on an input image signal; A luminance signal generating unit, a second luminance signal generating unit that generates a second luminance signal by a second method based on the input image signal, and an image signal based on the input image signal. Determining means for determining whether the image indicates a black-and-white image or a color image; and mixing means for mixing the first luminance signal and the second luminance signal in accordance with a result of the determination by the determining means. A signal processing device characterized by the above-mentioned. 2. The method according to claim 1, wherein the first method is an OutofGreen method, the second method is a SwitchY method, and the mixing means outputs the second luminance when the determination means determines that the image is a monochrome image. The signal processing apparatus according to claim 1, wherein the signal is output, and the first luminance signal is output when the signal is determined to be a color image. 3. The discriminating means outputs a signal indicating a black-and-white image, a color image or an intermediate between them, and if the signal is intermediate, the mixing means outputs the first signal at a rate based on the output signal value. 3. The signal processing device according to claim 2, wherein a luminance signal and the second luminance signal are mixed. 4. The image processing apparatus according to claim 1, further comprising: a detecting unit configured to detect a portion indicating an oblique line in an image indicated by the image signal based on the input image signal. The signal processing apparatus according to claim 1, wherein the first luminance signal and the second luminance signal are mixed according to a detection result by a detection unit. 5. The method according to claim 1, wherein the first method is an OutofGreen method, the second method is a SwitchY method, wherein the mixing means determines that the determination means is a black-and-white image, and the detection means is inclined. The signal processing apparatus according to claim 4, wherein the second luminance signal is output when a line is detected, and the first luminance signal is output otherwise. 6. The discriminating means outputs a signal indicating a black-and-white image, a color image or an intermediate between them, and the detecting means outputs a signal indicating a probability of being an oblique line,
The method according to claim 5, wherein when each signal indicates an intermediate value, the mixing unit mixes the first luminance signal and the second luminance signal at a ratio based on the output signal value. Signal processing device. 7. A signal processing device for processing an image signal obtained by imaging by an image sensor, wherein a first luminance signal is generated by a first method based on an input image signal. A luminance signal generating unit, a second luminance signal generating unit that generates a second luminance signal by a second method based on the input image signal, and an image signal based on the input image signal. Detecting means for detecting a portion indicating an oblique line in an image to be displayed, and mixing means for mixing the first luminance signal and the second luminance signal according to a detection result by the detecting means. Signal processing device. 8. The method according to claim 1, wherein the first method is an OutofGreen method, the second method is a SwitchY method, and the mixing unit is configured to execute the second method when the detecting unit detects an oblique line.
The signal processing device according to claim 7, wherein the first luminance signal is output in other cases, and the first luminance signal is output in other cases. 9. The detecting means outputs a signal indicating a probability of being an oblique line, and when the signal indicates an intermediate value,
9. The signal processing apparatus according to claim 8, wherein the mixing unit mixes the first luminance signal and the second luminance signal at a ratio based on the output signal value. 10. The signal according to claim 1, wherein the determination unit generates a saturation signal from the input image signal, and performs the determination based on the saturation signal. Processing equipment. 11. The apparatus according to claim 10, wherein said discriminating means has at least one of a means for applying a maximum value filter and a means for normalizing the chroma signal with brightness. A signal processing device according to claim 1. 12. The apparatus according to claim 1, wherein said oblique line detection means has at least one or more band-pass filters or high-pass filters for extracting an edge in an oblique direction, and performs detection based on an output result thereof. 12. The signal processing device according to any one of 7 to 11. 13. The oblique line detecting means includes at least one or more band-pass filters or high-pass filters for extracting oblique edges, and at least one or more low-pass filters, based on an output result thereof. The signal processing device according to claim 1, wherein the detection is performed. 14. The oblique line detecting means includes at least one of means for normalizing an output result of the band-pass filter or the high-pass filter by brightness or means for applying a maximum value filter. The signal processing device according to claim 12 or 13, wherein 15. The apparatus according to claim 1, wherein said first and second luminance signal generating means generates a plurality of luminance signals having different composition ratios of respective colors. Signal processing device. 16. The image pickup device according to claim 1, wherein the image pickup device has a filter of a primary color Bayer array, and at least one of the first and second luminance signal generating means has a composition ratio of a red signal, a green signal, and a blue signal. The signal processing device according to claim 1, wherein the signal processing device generates a luminance signal having a ratio of 1: 2 to 1. 17. The apparatus according to claim 1, wherein said first and second luminance signal generating means have means for generating a high-frequency emphasis signal based on a plurality of color signals, respectively.
7. The signal processing device according to any one of 6. 18. The signal processing apparatus according to claim 1, further comprising a high-frequency emphasis signal generation means for generating a high-frequency emphasis signal from the signal mixed by said mixing means. 19. A signal processing method for processing an image signal obtained by imaging by an image sensor, wherein a first luminance signal is generated by a first method based on an input image signal. A luminance signal generating step, a second luminance signal generating step of generating a second luminance signal by a second method based on the input image signal, and the image signal is generated based on the input image signal. A determining step of determining whether the image indicates a black-and-white image or a color image; and a mixing step of mixing the first luminance signal and the second luminance signal according to a determination result in the determining step. A signal processing method characterized by the above-mentioned. 20. The first method is an OutofGreen method, and the second method is a SwitchY method. In the mixing step, when the determination step determines that the image is a monochrome image, the second luminance is obtained. 20. The signal processing method according to claim 19, wherein a signal is output, and the first luminance signal is output when the signal is determined to be a color image. 21. A signal indicating a black-and-white image, a color image, or an intermediate therebetween is output in the determining step, and if the image is intermediate, the first step is performed at a rate based on the output signal value in the mixing step. The signal processing method according to claim 20, wherein a luminance signal and the second luminance signal are mixed. 22. The method according to claim 22, further comprising a detecting step of detecting, based on the input image signal, a portion indicating an oblique line in an image indicated by the image signal. 20. The signal processing method according to claim 19, wherein the first luminance signal and the second luminance signal are mixed according to a detection result in the detection step. 23. The first method is an OutofGreen method, the second method is a SwitchY method, and the mixing step determines that the image is a monochrome image in the determination step.
23. The signal processing method according to claim 22, wherein the second luminance signal is output when an oblique line is detected in the detection step, and the first luminance signal is output in other cases. . 24. The discriminating step outputs a signal indicating a black-and-white image, a color image or an intermediate between them, and the detecting step outputs a signal indicating a probability of being an oblique line, and each signal is 24. The signal processing method according to claim 23, wherein when indicating an intermediate value, the mixing step mixes the first luminance signal and the second luminance signal at a ratio based on the output signal value. . 25. A signal processing method for processing an image signal obtained by imaging with an image sensor, comprising: a first method for generating a first luminance signal by a first method based on an input image signal. A luminance signal generating step, a second luminance signal generating step of generating a second luminance signal by a second method based on the input image signal, and the image signal is generated based on the input image signal. A detecting step of detecting a portion indicating an oblique line in an image to be displayed, and a mixing step of mixing the first luminance signal and the second luminance signal according to a detection result in the detecting step. Signal processing method. 26. The first method is an OutofGreen method, and the second method is a SwitchY method. In the mixing step, when the detecting step detects an oblique line, the second luminance signal is output. 26. The signal processing method according to claim 25, further comprising outputting the first luminance signal otherwise. 27. A signal indicating a probability of being an oblique line is output in the detecting step, and when the signal indicates an intermediate value, the first step is performed at a rate based on the output signal value in the mixing step. 27. The signal processing method according to claim 26, wherein the first luminance signal and the second luminance signal are mixed. 28. The signal according to claim 19, wherein in the determination step, a saturation signal is generated from the input image signal, and the determination is performed based on the saturation signal. Processing method. 29. The method according to claim 28, wherein the determining step includes at least one of a step of applying a maximum value filter and a step of normalizing with a brightness to the saturation signal. The signal processing method as described. 30. The oblique line detecting step includes a band-pass filter processing step or a high-pass filter processing step of extracting an edge in an oblique direction, and the detection is performed based on an output result thereof. 30. The signal processing method according to any one of claims to 29. 31. The oblique line detecting step includes a band-pass filtering process or a high-pass filtering process for extracting an edge in an oblique direction, and a low-pass filtering process, and the detection is performed based on an output result thereof. 30. The signal processing method according to claim 25, wherein: 32. The oblique line detecting step includes at least one of a step of normalizing an output result of the band-pass filtering step or the high-pass filtering step with brightness and a step of applying a maximum value filter. 32. The signal processing method according to claim 30, comprising: 33. The method according to claim 19, wherein in the first and second luminance signal generating steps, a plurality of luminance signals having different composition ratios of respective colors are generated. Signal processing method. 34. The image pickup device having a primary color Bayer array of filters, wherein at least one of the first and second luminance signal generation steps includes a red signal, a green signal, and a blue signal. The signal processing method according to any one of claims 19 to 33, wherein a luminance signal having a ratio of 1 to 2 to 1 is generated. 35. The method according to claim 19, wherein the first and second luminance signal generating steps each include a step of generating a high-frequency emphasis signal based on a plurality of color signals. 3. The signal processing method according to 1. 36. The signal processing method according to claim 19, further comprising a high-frequency emphasis signal generation step of generating a high-frequency emphasis signal from the signal mixed in the mixing step. 37. An imaging device comprising the signal processing device according to claim 1. Description: 38. The imaging apparatus according to claim 37, wherein said imaging apparatus includes a scanner, a copier, a facsimile, a digital camera, and a digital video camera. 39. A program executable by the information processing apparatus, the information processing apparatus executing the program comprising:
A non-transitory computer-readable storage medium storing a program that functions as the signal processing device according to claim 1. 40. A program executable by an information processing apparatus having a program code for implementing the signal processing method according to claim 19. 41. A storage medium storing the program according to claim 39.