JP2000350031A - Image processor, image processing method and recording medium with image processing program recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital image that has optimum contrast or saturation of only those parts of which a person is visually sensitive for contrast of. SOLUTION: This image processor is provided with a low-pass filter 6 that obtains a low frequency image from luminance image data Y of a digital image, a subtractor 7 that obtains luminance high frequency image from the luminance image data Y and the luminance low frequency image, an LUT 9 that modulates the luminance high frequency image, and an intensity calculation section 8 that calculates modulation intensity of the luminance high frequency image. The intensity calculation section 8 calculates the modulation intensity, by which the luminance high frequency image has an optimum contrast, on the basis of the luminance image data Y or image data of the luminance high frequency image from the subtractor 7. Since the LUT 9 modulates only the luminance high frequency images, to which a person is sensitive for contrast by this modulation intensity, the reproduced digital image becomes an optimum in contract, the part of which the person is sensitive for contract and the image with satisfactory quality as a whole can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus which performs image processing on image data of an image recorded on a photographic film such as a negative film and supplies the processed image data to a photographic printing apparatus, an image processing method, and an image processing method. The present invention relates to a recording medium recording an image processing program for causing a processing device to execute image processing, and in particular, an image processing device capable of partially adjusting contrast or saturation in an image, an image processing method, And a recording medium on which an image processing program is recorded.

[0002]

2. Description of the Related Art Conventionally, as a photographic printing apparatus for printing an image recorded on a negative film on photographic paper, an analog printer for directly exposing the photographic paper via a negative film, a scanner for printing an image recorded on the negative film, and the like. Various types of digital printers have been proposed in which a photographic paper is exposed on the basis of image data obtained by temporarily reading the photographic paper. In particular, a digital printer is used in combination with an image processing apparatus that performs image processing such as color correction, density correction, gradation conversion, and the like on image data, so that color correction, density correction, and gradation correction that cannot be realized by an analog printer. It has the advantage of being able to perform tone conversion and the like, and of being able to easily and quickly obtain an image according to the needs of the customer, and is currently widely used together with the image processing apparatus described above.

As an image processing apparatus used with the digital printer, for example, a configuration shown in FIG. 12 is known. This image processing apparatus is capable of adjusting the degree of color vividness in a digital image, that is, the saturation, in order to improve the quality of a finished photograph, and a color space converter (hereinafter abbreviated as CSC). 51 and 52 and a look-up table (hereinafter abbreviated as LUT) 53 at least.

[0004] The CSC 51 generates luminance image data Y and color image data C1 and C2 for each pixel based on image data R, G, and B corresponding to red, green, and blue. The generated luminance image data Y is input to the CSC 52, while the color image data C1 and C2 are
53 is input. The CSC 51 generates luminance image data Y and color image data C1 and C2, for example, by the following calculations.

[0005] Y = 0.299R + 0.587G + 0.1
14B C1 = RY = 0.701R-0.587G-0.1
14B C2 = BY = -0.299R-0.587G + 0.8
The 86B LUT 53 converts the color image data C1 and C2 input from the CSC 51 into color image data C1 ′ and C2 ′ using a certain function F. The above function F
Can be arbitrarily set by the operator, and the function F
Depending on the setting of, for example, the input value as it is as the output value,
Alternatively, a value larger than the input value
52.

The CSC 52 includes luminance image data Y from the CSC 51 and color image data C1 'from the LUT 53.
・ Each image data R ′, G ′, B ′ based on C2 ′
Is generated for each pixel. For example, each image data R ′, G ′, B ′ is generated by the following calculation.

R ′ = Y + C1 ′ G ′ = Y− (0.299 / 0.587) C1 ′ − (0.
114 / 0.587) C2 ′ B ′ = Y + C2 ′ In the above configuration, only the color image data C1 and C2 are changed without changing the luminance image data Y, and the image data R ′, G ′ and B ′ are changed. Image data R '
-It is possible to change only the color (saturation) of the digital image as a whole while maintaining the density of the entire digital image composed of G 'and B' as it is. At this time, depending on the setting of the function F of the LUT 53, various color image data C1 ′ · C
Since 2 ′ can be obtained, the saturation of the entire image can be variously adjusted based on the image data R ′, G ′, and B ′ obtained by the CSC 52.

[0008]

By the way, the quality of a finished photograph is determined by how vividly a portion of the photograph where a human can easily feel contrast is expressed. Here, the portion where a human easily feels the contrast generally indicates a portion where the gradation change is rich, for example, “human” as a main subject. Also, conversely,
The part where humans hardly feel the contrast refers to a part having almost no gradation change, such as “blue sky”, “white clouds”, “dark night view”, “ground”, and “snow mountain”. Therefore, for example, when a photograph of “Human” is taken with “Snowy Mountain” as a background, the more vivid the “Human” is expressed than “Snowy Mountain”, the better the quality as a photograph.

However, in the configuration of FIG. 12, as described above, the saturation of the entire digital image only changes uniformly. For example, it is not possible to adjust only the saturation of the main subject portion where the contrast is easily felt. Can not. As a result, with the above configuration, it is not possible to obtain a high-quality photograph in which the main subject is emphasized. Note that there is a method in which an operator finds an LUT capable of partially converting saturation by trial and error while watching a monitor or the like, but this is time-consuming and troublesome, and is not realistic.

On the other hand, as an image processing apparatus capable of enhancing an outline in an image, for example, a configuration shown in FIG. 13 is known.
In this apparatus, an edge / flat portion discriminating section 61 discriminates an edge portion and a flat portion in an image based on the degree of correlation between color signal changes between RGB. While enhancing the medium frequency component and the high frequency component of the digital image obtained at 62, the flat portion performs gain control to suppress the enhancement of the medium frequency component, and thereafter, the low frequency component from the filter processing unit 62, The medium frequency component and the high frequency component are combined. Since the flat portion contains information of the film particles that are unpleasant for human eyes, in the above configuration, by performing the gain control, while suppressing the appearance of the image of the film particles in the flat portion, It is possible to perform edge enhancement.

Here, it is known that a portion of the image where a human easily feels the contrast corresponds to the medium-frequency and high-frequency components of the digital image. Accordingly, only the middle frequency and high frequency components are emphasized without emphasizing low frequency components.
According to the configuration described above, in addition to the effect of edge enhancement, it is considered that an effect of enhancing only a portion where humans can easily sense contrast is obtained, and it is presumed that this improves the photographic quality.

However, in the above-described apparatus, only the binary control of emphasizing the intermediate frequency component or suppressing the emphasis is performed in accordance with the discrimination result of the edge / flat portion. It is not emphasized with strong intensity.
As a result, even if the appearance of film particles can be suppressed, it cannot be said that edge enhancement has been performed well, and the quality of the obtained photograph is not necessarily good.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to modulate a medium frequency component and a high frequency component of a digital image with an optimum intensity to ensure a high-quality photograph. An object of the present invention is to provide an image processing apparatus, an image processing method, and a recording medium on which an image processing program can be obtained.

[0014]

According to the first aspect of the present invention, there is provided an image processing apparatus comprising: a low-frequency component and a medium-frequency / high-frequency component of a digital image for each pixel of the digital image; An image processing apparatus comprising: a main component generating unit that generates the intermediate frequency component; a modulating unit that modulates the medium frequency and high frequency component; and a combining unit that combines the modulated medium frequency and high frequency component with the original low frequency component. And an intensity calculating means for calculating the modulation intensity of the intermediate frequency / high frequency component corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. -It is characterized by modulating high frequency components.

According to the above arrangement, when the main component generation means generates the low frequency component and the medium frequency / high frequency component of the digital image, the medium frequency / high frequency component is modulated (emphasized or weakened) by the modulation means. The modulated medium-frequency / high-frequency component is combined with the low-frequency component by the combining means,
A digital image is reproduced.

At this time, the modulating means modulates the intermediate frequency / high frequency component with the modulation intensity calculated by the intensity calculating means, and the modulation intensity corresponds to the optimum contrast or the optimal saturation of the medium frequency / high frequency component. The low-frequency component of the digital image is constant before and after the modulation of the medium-frequency and high-frequency components. Therefore, the digital image after the synthesis of the above-described intermediate frequency / high frequency component and the low frequency component is
The part containing the high frequency component appears as the optimum contrast or the optimum saturation. If the medium frequency / high frequency component is composed of, for example, luminance image data, the medium frequency / high frequency component
The part containing the high-frequency component is an image with the optimum contrast. If the medium-frequency and high-frequency components are composed of image data corresponding to, for example, RGB colors, the part containing the medium-frequency and high-frequency components has the optimum saturation. It is an image.

Further, in the above configuration, in the digital image, only the medium-frequency and high-frequency components which are easy for human eyes to perceive the contrast are modulated. Appear as an optimum contrast or an optimum saturation.

Therefore, according to the above configuration, when a photograph is printed based on the digital image after the synthesis, the contrast or saturation of a portion where a human can easily feel the contrast is optimally expressed, and a high-quality photograph as a whole is obtained. Obtainable. In addition, since the medium frequency and high frequency components of a digital image are often included in the edge portion of the image, according to the above configuration, the modulation of the medium frequency and high frequency components
The edge portion can be emphasized and weakened.

According to a second aspect of the present invention, there is provided an image processing apparatus according to the first aspect, wherein:
The intensity calculating means calculates the variance of the first histogram indicating the relationship between the image data of each pixel of the digital image and the frequency by the modulation of the medium frequency / high frequency component, and calculates the variance for each region where the variance can be calculated. The method is characterized in that the modulation intensity of the medium frequency / high frequency component is calculated such that the variance corresponds to the optimum contrast or the optimum saturation of the medium frequency / high frequency component.

In general, when a digital image includes a main subject in which a human can easily see the contrast with the eyes, the first histogram indicates that the frequency has a maximum value in the average value of the image data of each main subject. Draw various shapes. Therefore, the area including the maximum point in the first histogram is associated with the area where the variance can be calculated. Note that the average value corresponds to the average density of the main subject, whether the image data is luminance image data or RGB image data.

Here, in the above configuration, the variance of the first histogram in the digital image after the modulation of the intermediate frequency and high frequency components is changed by the modulation of the intermediate frequency and high frequency components for each region where the variance can be calculated. The variance corresponds to the optimal contrast or the optimal saturation of the high frequency component. First
Such a variance of the histogram is, for example, to adjust the variance of the histogram indicating the relationship between the image data of each pixel of the medium frequency and high frequency components and the frequency, and between the adjacent pixels of the image data of the digital image This can be realized by adjusting the variance of the histogram indicating the relationship between the difference of the frequency and the frequency.

By realizing the variance in the first histogram, the first histogram expands and contracts around the average density of the main subject. That is, the average density of the main subject does not shift. As a result, the main subject does not become entirely bright or dark due to the modulation of the medium frequency / high frequency components. Therefore, according to the above configuration, it is possible to realize the optimal contrast or the optimal saturation in such a portion while maintaining the average density of the portion where the human can easily feel the contrast.

According to a third aspect of the present invention, in the image processing apparatus according to the first or second aspect of the present invention, in order to solve the above-mentioned problem, the intensity calculating means performs the modulation of the medium-frequency / high-frequency component to perform the modulation. The variance of the second histogram indicating the relationship between the image data of each pixel of the medium frequency / high frequency component and the frequency thereof is a variance corresponding to the optimum contrast or the optimum saturation of the medium frequency / high frequency component. It is characterized in that the modulation intensities of the intermediate frequency and high frequency components are calculated.

Generally, since the medium-frequency and high-frequency components of a digital image often occur in a portion where image data changes in the digital image, the second histogram is
For example, a figure whose center value is a value corresponding to the average value of the image data of the main subject portion and whose frequency has the maximum value is drawn at the center. Therefore, in the second histogram, the area including the maximum point is associated with the area where the variance can be calculated.

Here, in the above configuration, the intermediate frequency and high frequency components are modulated such that the variance of the second histogram is the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency and high frequency components. That is, the medium frequency / high frequency components themselves, which are often included in the main subject portion, are directly modulated. As a result, when a digital image is reproduced by combining the modulated medium-frequency and high-frequency components with the original low-frequency component, the main subject portion containing a large amount of such medium-frequency and high-frequency components has an optimum contrast or optimum color. Appears as a degree image.

Also, even if the variance of the second histogram is changed, the image data at the time when the maximum point is taken in the second histogram does not change. Therefore, the average value of the image data of the main subject corresponding to the image data is also changed. It does not change. Thereby, in the reproduced digital image,
The main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, an optimum contrast or an optimum saturation can be realized.

According to a fourth aspect of the present invention, in the image processing apparatus according to the first or second aspect of the present invention, in order to solve the above-mentioned problem, the intensity calculating means modulates the medium frequency / high frequency component to generate The variance of the third histogram indicating the relationship between the difference between adjacent pixels of the image data of the digital image and the frequency thereof becomes the variance corresponding to the optimal contrast or the optimal saturation of the medium-frequency / high-frequency components. It is characterized in that the modulation intensities of the intermediate frequency and high frequency components are calculated.

Generally, the difference between adjacent pixels of image data of a digital image takes a large value at a portion where the image data changes in the digital image. Is drawn with the value corresponding to the average value of the center as the center, and the figure having the maximum value at the center. Therefore, the area including the maximum point in the third histogram is associated with the area where the variance can be calculated.

Here, in the above configuration, the intermediate frequency and high frequency components are modulated such that the variance of the third histogram becomes the variance corresponding to the optimal contrast or the optimal saturation of the above intermediate frequency and high frequency components. Thus, when a digital image is reproduced by combining the modulated medium- and high-frequency components with the original low-frequency component, the image data of the digital image spreads around the average value of the image data of the main subject portion. (Or narrowing), the main subject portion appears as an image with optimal contrast or optimal saturation.

Further, even if the variance of the third histogram is changed, the difference between the image data when the maximum point is obtained in the third histogram does not change. Therefore, the image data of the main subject corresponding to the difference between the image data. The average value of does not change. As a result, in the reproduced digital image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, an optimum contrast or an optimum saturation can be realized.

According to a fifth aspect of the present invention, there is provided an image processing apparatus according to any one of the first to fourth aspects, further comprising an image data corresponding to each color of RGB of the digital image. Further comprising a luminance image generating means for generating a luminance image based on the main component generating means,
The low frequency component is generated based on the luminance image, and the medium frequency / high frequency component is generated based on the luminance image and the low frequency component.

According to the arrangement, the main component generation means generates the low frequency component of the digital image from the luminance image generated by the luminance image generation means, and subtracts the low frequency component from the luminance image, for example. Generates medium and high frequency components of the digital image. As a result, the generated low-frequency component and medium-frequency / high-frequency component become a luminance low-frequency component and a luminance medium-frequency / high-frequency component, respectively.

Therefore, the luminance (density) of the original digital image can be changed, for example, in the main subject portion by modulating the luminance middle frequency / high frequency component and then combining it with the luminance low frequency component. Thus, it is possible to reliably obtain a digital image having an optimum contrast in a portion where a human easily feels the contrast.

According to a sixth aspect of the present invention, there is provided an image processing apparatus according to any one of the first to fourth aspects, further comprising an image data corresponding to each color of RGB of the digital image. Further comprising a luminance image generating means for generating a luminance image based on the main component generating means,
The low frequency component is generated based on the luminance image, and the medium frequency / high frequency component is generated for each of RGB based on the image data of the digital image and the low frequency component.

According to the above arrangement, the main component generating means generates the low frequency components of the digital image from the luminance image generated by the luminance image generating means, and generates the low frequency components of the digital image from the image data corresponding to each of the RGB colors. By subtracting the low frequency component, for example, a medium frequency / high frequency component of the digital image is generated. As a result, the generated low frequency component becomes a luminance low frequency component, while the middle frequency / high frequency component is R
This is a component corresponding to each color of GB.

Therefore, by modulating the medium-frequency and high-frequency components of each color and combining them with the low-frequency component of the luminance, the saturation of the original digital image can be changed, for example, in the main subject portion. It is possible to reliably obtain a digital image with an optimal saturation in a portion where a human can easily feel contrast.

According to a seventh aspect of the present invention, in the image processing apparatus according to any one of the first to fourth aspects of the present invention, the main component generating means is configured to control each of RGB colors of the digital image. The low-frequency component is generated for each of RGB based on the image data corresponding to the image data, and the medium-frequency and high-frequency components are generated for each of RGB based on the image data of the digital image and the low-frequency component of the corresponding color. It is characterized by generating.

According to the above configuration, the low-frequency component and the medium-frequency / high-frequency components generated by the main component generation means are:
Both are low-frequency components and medium-frequency / high-frequency components corresponding to the RGB colors of the digital image. Therefore, after modulating the medium-frequency and high-frequency components of each color, by combining with the low-frequency component of the corresponding color, the saturation of the original digital image can be changed, for example, in the main subject portion, It is possible to reliably obtain a digital image with an optimal saturation in a portion where a human can easily feel contrast.

According to an eighth aspect of the present invention, there is provided an image processing apparatus according to any one of the first to seventh aspects, further comprising an input means for designating and inputting the modulation intensity. The modulating means modulates the medium-frequency and high-frequency components with the inputted modulation strength when the modulation strength is designated and input by the input means.

According to the above configuration, the modulation intensity of the intermediate frequency / high frequency component can be separately designated and input by the input means, and the intermediate frequency / high frequency component can be modulated with the input modulation intensity. Thus, it is possible to obtain an image having an optimum contrast and saturation according to the user's desire.

In theory, even if the image has the optimum contrast and the optimum saturation, the main subject portion is not suitable for the human eye due to the density and color of the surrounding image. Sometimes it does not appear as an image. However, in the above configuration, the contrast and the saturation of the main subject can be finely adjusted by separately inputting the modulation intensity by the input means, thereby ensuring an image in which the contrast and the saturation are actually optimal. Can be obtained.

Further, the medium frequency and high frequency components are, for example, RG
When generated for each of the colors B, while modulating the medium- and high-frequency components of a specific color of RGB,
By specifying and inputting the modulation intensity of the corresponding color by the input means so as not to modulate the medium-frequency and high-frequency components of other colors, only the portion including the specific color in the digital image after synthesis is adjusted in saturation. You can also.

According to a ninth aspect of the present invention, there is provided an image processing method for generating a low frequency component and a medium frequency / high frequency component of a digital image for each pixel of the digital image. A second step of calculating a modulation intensity of the intermediate frequency / high frequency component corresponding to an optimum contrast or an optimum saturation of the intermediate frequency / high frequency component; and modulating the intermediate frequency / high frequency component with the modulation intensity. The method is characterized by including a third step and a fourth step of synthesizing the modulated medium frequency / high frequency component and the original low frequency component.

According to the above configuration, the low frequency component and the medium frequency / high frequency component are generated from the digital image, and only the medium frequency / high frequency component is modulated (emphasized or weakened) with the calculated modulation intensity. By synthesizing with the original low frequency component, a digital image is reproduced.

At this time, the modulation intensity is an intensity corresponding to the optimum contrast or the optimum saturation of the intermediate frequency / high frequency component, and the low frequency component of the digital image is constant before and after the modulation of the intermediate frequency / high frequency component. Therefore, in the digital image after the combination of the intermediate frequency / high frequency component and the low frequency component, a portion including the intermediate frequency / high frequency component appears as the optimal contrast or the optimal saturation. Note that if the medium-frequency / high-frequency components are composed of, for example, luminance image data,
The part containing the above-mentioned medium frequency / high frequency component is an image having the optimum contrast.
If the image data is composed of image data corresponding to each of the above colors, the portion including the above-mentioned medium-frequency and high-frequency components is an image having the optimum saturation.

In addition, in the above-described configuration, in the digital image, only the medium-frequency and high-frequency components that are easy for human eyes to perceive the contrast are modulated. Appear as an optimum contrast or an optimum saturation.

Therefore, according to the above configuration, when a photograph is printed on the basis of the digital image after the synthesis, the contrast or saturation of a portion where a human can easily feel the contrast is optimally displayed, and a high-quality photograph as a whole is obtained. Obtainable. In addition, since the medium frequency and high frequency components of a digital image are often included in the edge portion of the image, according to the above configuration, the modulation of the medium frequency and high frequency components
The edge portion can be emphasized and weakened.

According to a tenth aspect of the present invention, there is provided an image processing method comprising:
In order to solve the above-mentioned problem, in the configuration of claim 9, the second step includes, by modulating the medium-frequency / high-frequency components, changing a relationship between image data of each pixel of the digital image and its frequency. The variance of the first histogram shown is
A step of calculating the modulation intensity of the intermediate frequency / high frequency component such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component for each region where the variance can be calculated. .

In general, when a digital image includes a main subject that is easily perceived by human eyes, the first histogram indicates that the frequency has a maximum value in the average value of the image data of each main subject. Draw various shapes. Therefore, the area including the maximum point in the first histogram is associated with the area where the variance can be calculated. Note that the average value corresponds to the average density of the main subject, whether the image data is luminance image data or RGB image data.

Here, in the above configuration, the variance of the first histogram in the digital image after the modulation of the intermediate frequency / high frequency component is determined by the optimum contrast or the optimal saturation of the intermediate frequency / high frequency component for each region where the variance can be calculated. The first histogram expands and contracts around the average density of the main subject, but the average density of the main subject does not shift. As a result, the main subject does not become entirely bright or dark due to the modulation of the medium frequency / high frequency components. Therefore, according to the above configuration, it is possible to realize the optimal contrast or the optimal saturation in such a portion while maintaining the average density of the portion where the human can easily feel the contrast.

An image processing method according to an eleventh aspect of the present invention
In order to solve the above-mentioned problem, in the configuration according to claim 9 or 10, the second step includes the step of modulating the medium-frequency / high-frequency component to obtain image data for each pixel of the medium-frequency / high-frequency component and the image data. Calculating the modulation intensity of the intermediate frequency / high frequency component such that the variance of the second histogram indicating the relationship with the frequency is the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. It is characterized by:

In general, the medium frequency and high frequency components of a digital image are often generated in a portion where image data changes in the digital image.
For example, a figure whose center value is a value corresponding to the average value of the image data of the main subject portion and whose frequency has the maximum value is drawn at the center. Therefore, in the second histogram, the area including the maximum point is associated with the area where the variance can be calculated.

Here, in the above configuration, the intermediate frequency / high frequency component is modulated so that the variance of the second histogram is the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. That is, the medium frequency / high frequency components themselves, which are often included in the main subject portion, are directly modulated. As a result, when a digital image is reproduced by combining the modulated medium-frequency and high-frequency components with the original low-frequency component, the main subject portion containing a large amount of such medium-frequency and high-frequency components has an optimum contrast or optimum color. Appears as a degree image.

Further, even if the variance of the second histogram is changed, the image data at the time when the maximum point is taken in the second histogram does not change. Therefore, the average value of the image data of the main subject corresponding to the image data is also changed. It does not change. Thereby, in the reproduced digital image,
The main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, an optimum contrast or an optimum saturation can be realized.

An image processing method according to a twelfth aspect of the present invention
In order to solve the above-mentioned problem, in the configuration according to claim 9 or 10, the second step includes a step of modulating the intermediate-frequency / high-frequency component and calculating a difference between adjacent pixels of image data of the digital image. Calculating the modulation intensity of the intermediate frequency / high frequency component such that the variance of the third histogram indicating the relationship with the frequency is the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. It is characterized by:

Generally, the difference between adjacent pixels of image data of a digital image takes a large value in a portion where the image data changes in the digital image. Is drawn with the value corresponding to the average value of the center as the center, and the figure having the maximum value at the center. Therefore, the area including the maximum point in the third histogram is associated with the area where the variance can be calculated.

Here, in the above configuration, the intermediate frequency / high frequency component is modulated so that the variance of the third histogram is the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. Thus, when a digital image is reproduced by combining the modulated medium- and high-frequency components with the original low-frequency component, the image data of the digital image spreads around the average value of the image data of the main subject portion. (Or narrowing), the main subject portion appears as an image with optimal contrast or optimal saturation.

Even if the variance of the third histogram is changed, the difference between the image data at the time when the maximum point is taken in the third histogram does not change. Therefore, the image data of the main subject corresponding to the difference between the image data is obtained. The average value of does not change. As a result, in the reproduced digital image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, an optimum contrast or an optimum saturation can be realized.

According to a thirteenth aspect of the present invention, there is provided a recording medium on which an image processing program is recorded, wherein a low frequency component and a medium frequency / high frequency component of a digital image are converted for each pixel of the digital image. A first process for generating; a second process for calculating a modulation intensity of the intermediate frequency / high frequency component corresponding to an optimal contrast or an optimal saturation of the intermediate frequency / high frequency component;
An image processing program for causing a computer to execute a third process of modulating a high-frequency component and a fourth process of synthesizing the modulated intermediate-frequency / high-frequency component and the original low-frequency component is recorded. It is characterized by:

According to the above configuration, the low frequency component and the medium frequency / high frequency component are generated from the digital image, and only the medium frequency / high frequency component is modulated (emphasized or weakened) with the calculated modulation intensity. By synthesizing with the original low frequency component, a digital image is reproduced.

At this time, the modulation intensity is an intensity corresponding to the optimum contrast or the optimum saturation of the medium frequency / high frequency component, and the low frequency component is constant before and after the modulation of the medium frequency / high frequency component. In the digital image after the combination of the intermediate frequency / high frequency component and the low frequency component, a portion including the intermediate frequency / high frequency component appears as the optimal contrast or the optimal saturation. If the medium-frequency and high-frequency components are composed of, for example, luminance image data, the portion including the medium-frequency and high-frequency components is an image with optimal contrast,
If the medium-frequency / high-frequency components are composed of image data corresponding to, for example, RGB colors, the portion including the medium-frequency / high-frequency components is an image with optimal saturation.

In addition, in the above-described configuration, in the digital image, only the medium-frequency and high-frequency components that are easy for human eyes to see the contrast are modulated. Appear as an optimum contrast or an optimum saturation.

Therefore, according to the above configuration, a computer (for example, an image processing apparatus) is executed using a recording medium on which a program for executing such image processing is recorded, and a photograph is printed based on the reproduced digital image. In such a case, it is possible to optimally express the contrast or the saturation of the part where the human can easily feel the contrast, and obtain a high-quality photograph as a whole. In addition, since the medium frequency and high frequency components of a digital image are often contained in the edge portion of the image, according to the above configuration, the edge portion can be emphasized and weakened by modulating the medium frequency and high frequency components. it can.

According to a fourteenth aspect of the present invention, there is provided a recording medium storing an image processing program according to the thirteenth aspect, wherein the second processing is performed on the medium frequency / high frequency component. By the modulation, the variance of the first histogram indicating the relationship between the image data of each pixel of the digital image and the frequency is changed to the optimal contrast or the optimal saturation of the medium frequency / high frequency component for each region where the variance can be calculated. It is characterized in that it is a process of calculating the modulation intensity of the medium frequency / high frequency component so as to have a corresponding variance.

In general, when a digital image includes a main subject in which a human can easily see the contrast, the first histogram indicates that the frequency has a maximum value in the average value of the image data of each main subject. Draw various shapes. Therefore, the area including the maximum point in the first histogram is associated with the area where the variance can be calculated. Note that the average value corresponds to the average density of the main subject, whether the image data is luminance image data or RGB image data.

Here, in the above configuration, the variance of the first histogram in the digital image after the modulation of the intermediate frequency / high frequency component is determined by the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component for each region where the variance can be calculated. The first histogram expands and contracts around the average density of the main subject, but the average density of the main subject does not shift. As a result, the main subject does not become entirely bright or dark due to the modulation of the medium frequency / high frequency components. Therefore, according to the above configuration, it is possible to realize the optimal contrast or the optimal saturation in such a portion while maintaining the average density of the portion where the human can easily feel the contrast.

According to a fifteenth aspect of the present invention, there is provided a recording medium storing an image processing program according to the thirteenth or fourteenth aspect of the present invention, wherein the second process comprises Due to the modulation of the components, the variance of the second histogram indicating the relationship between the image data of each pixel of the intermediate frequency and high frequency components and the frequency thereof is changed to the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency and high frequency components. This is a process for calculating the modulation intensity of the medium frequency / high frequency component such that

Generally, the medium frequency and high frequency components of a digital image are often generated in a portion where image data changes in the digital image.
For example, a figure whose center value is a value corresponding to the average value of the image data of the main subject portion and whose frequency has the maximum value is drawn at the center. Therefore, in the second histogram, the area including the maximum point is associated with the area where the variance can be calculated.

Here, in the above configuration, the intermediate frequency / high frequency component is modulated so that the variance of the second histogram becomes the variance corresponding to the optimal contrast or the optimal saturation of the above intermediate frequency / high frequency component. That is, the medium frequency / high frequency components themselves, which are often included in the main subject portion, are directly modulated. As a result, when a digital image is reproduced by combining the modulated medium-frequency and high-frequency components with the original low-frequency component, the main subject portion containing a large amount of such medium-frequency and high-frequency components has an optimum contrast or optimum color. Appears as a degree image.

Even if the variance of the second histogram is changed, the image data at the time when the maximum point is taken in the second histogram does not change. Therefore, the average value of the image data of the main subject corresponding to the image data is also changed. It does not change. Thereby, in the reproduced digital image,
The main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, an optimum contrast or an optimum saturation can be realized.

According to a sixteenth aspect of the present invention, there is provided a recording medium storing an image processing program according to the thirteenth or fourteenth aspect, wherein the second processing is performed in the medium frequency / high frequency mode. Due to the modulation of the components, the variance of the third histogram indicating the relationship between the difference between the adjacent pixels of the image data of the digital image and the frequency thereof is changed to the variance corresponding to the optimal contrast or the optimal saturation of the medium frequency / high frequency components. This is a process for calculating the modulation intensity of the medium frequency / high frequency component such that

Generally, the difference between adjacent pixels of image data of a digital image takes a large value in a portion where the image data changes in the digital image. Is drawn with the value corresponding to the average value of the center as the center, and the figure having the maximum value at the center. Therefore, the area including the maximum point in the third histogram is associated with the area where the variance can be calculated.

Here, in the above configuration, the intermediate frequency / high frequency component is modulated such that the variance of the third histogram is the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. Thus, when a digital image is reproduced by combining the modulated medium- and high-frequency components with the original low-frequency component, the image data of the digital image spreads around the average value of the image data of the main subject portion. (Or narrowing), the main subject portion appears as an image with optimal contrast or optimal saturation.

Even if the variance of the third histogram is changed, the difference between the image data at the time when the maximum point is taken in the third histogram does not change. Therefore, the image data of the main subject corresponding to the difference between the image data. The average value of does not change. As a result, in the reproduced digital image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, an optimum contrast or an optimum saturation can be realized.

[0081]

[Embodiment 1] One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the digital exposure system according to the present embodiment includes a film scanner 1, an image processing device 2, and a photographic printing device 3.

The film scanner 1, for example, converts light obtained through a photographic film negative film into a CCD.
(Charge Coupled Device)
It reads an image recorded on a negative film and outputs image data corresponding to the image to the image processing device 2 for each of R, G, and B.

The photographic printing device 3 is a digital printer that prints an image on photographic paper by exposing photographic paper, which is a photosensitive material, based on image data from the image processing device 2. The exposure unit that exposes the photographic paper may be any unit that can modulate the irradiation light on the photographic paper according to the digital image data. For example, a PLZT exposure head, a DMD
(Digital micromirror device), LCD (liquid crystal display), LED panel, laser, FOCRT
(Fiber Optic Cathode Ray Tube), CRT, etc.

The photographic printing apparatus 3 may have a structure capable of performing both scanning of a negative film and exposure of photographic paper. In this case, by configuring the digital exposure system with the image processing device 2 and the photographic printing device 3, the system can be simplified.

The image processing device 2 performs image processing such as saturation adjustment on the image data from the film scanner 1,
The processed image data is supplied to the photoprinting apparatus 3. As shown in FIG. 1, the LUT 4 and the RGB / YCC
A conversion unit 5, a low-pass filter (hereinafter abbreviated as LPF) 6, a subtracter 7, an intensity calculation unit 8 (intensity calculation unit), an LUT 9 (modulation unit), a synthesis unit 10 (synthesis unit), It has a YCC / RGB conversion unit 11 and an input unit 12 (input means).

The LUT 4 performs color conversion and density conversion on image data R, G, and B corresponding to red, green, and blue sent from the film scanner 1. Note that the color conversion here is a process of eliminating the color of the negative film included in the image data RGB, and the density conversion is a process of changing the brightness of the entire image to be appropriate. The color and transmittance of a negative film vary from manufacturer to manufacturer, and even from the same manufacturer, it depends on the type of film. Therefore, by performing each of the above-described conversions in the LUT 4, the influence on the image data RGB of the negative film can be removed for each negative film.

The RGB / YCC converter 5 converts the image data R
The luminance image data Y and the color image data C1 and C2 are generated based on G and B, for example, by the above-described equations. The generated luminance image data Y is supplied to the LPF 6 and the LPF 6 so that any of the first and second embodiments described below can be applied.
The color image data C1 and C2 are input to the YCC / RGB conversion unit 11 while being input to the subtractor 7 and the intensity calculation unit 8.

Note that the luminance image data Y may be input only to the LPF 6 and the subtractor 7.
In this case, the intensity calculator 8 can calculate the intensity only by the method of the first embodiment described later.

The LPF 6 extracts only a low-frequency image (blurred image) from the luminance image data Y from the RGB / YCC converter 5. Hereinafter, the extracted low-frequency image is referred to as a luminance low-frequency image. In the LPF 6, specifically, for example, a moving average filter, a median filter, a Gaussian filter, or the like is used, and a masking process is performed on all pixels while shifting a pixel of interest, thereby obtaining a low-luminance image. The luminance low-frequency image obtained by the LPF 6 is input to the subtractor 7 and the synthesis unit 10.

Here, the moving average filter, median filter, and Gaussian filter will be briefly described as follows.

The moving average filter, as shown in FIG.
For example, it is a 3 × 3 filter, and the coefficients of each pixel are all the same. By masking the image data using this moving average filter, the data of the target pixel (the pixel at the center) is replaced with the sum of 1/9 data of the nine pixels. In other words, the data of the target pixel is obtained by adding the data of the target pixel and the data of the eight peripheral pixels and dividing the sum by nine.

The median filter replaces the data of the pixel of interest with the median value of the arranged image data when the image data within a predetermined range is arranged from the smallest one. For example, if the image data is within the range of 3 × 3, as shown in FIG.
When these image data are arranged in order from the smaller one in the case of the values shown in (5), "5, 25, 50, 60, 70, 8"
0, 90, 100, 100 ", and the median is 70
It is. Therefore, in this case, the current image data “50” of the target pixel is replaced with “70” as shown in FIG. By using such a median filter, an edge having a large luminance difference is preserved to some extent (the edge is hardly blurred).

The Gaussian filter is, for example, a 3 × 3 filter shown in FIG. 4, and multiplies the data of each pixel by the coefficient shown in FIG. 4 and divides the sum by 16 which is the sum of the coefficients to obtain the value of the pixel of interest. It is assumed to be image data. If this Gaussian filter is used, it is possible to obtain a nearly natural blurring effect as if blurred using a lens.

Note that the size and coefficient of the filter are not limited to the above, but may be appropriately set according to the processing speed and processing capability.

The subtractor 7 subtracts the luminance low-frequency image obtained by the LPF 6 from the luminance image data Y from the RGB / YCC converter 5 to generate a luminance medium-frequency image and a luminance high-frequency image, respectively. Therefore, the LPF 6 and the subtractor 7 constitute the main component generation means described in the claims. Hereinafter, the medium-frequency image and the high-frequency image are collectively referred to as a high-frequency image.

The intensity calculation unit 8 outputs the image data of the high-frequency luminance image from the subtractor 7 or the RGB / YCC conversion unit 5
The modulation intensity of the high-frequency luminance image is calculated on the basis of the luminance image data Y from FIG.

The LUT 9 creates an LUT based on the intensity calculated by the intensity calculator 8 and modulates (emphasizes or weakens) the high-frequency luminance image from the subtractor 7 with this LUT. The synthesizing unit 10 synthesizes the luminance low-frequency image obtained by the LPF 6 and the luminance high-frequency image obtained by the LUT 9 to generate luminance image data Y ′.

The YCC / RGB conversion unit 11 is
The image data R ′, G ′, and B ′ are generated based on the luminance image data Y ′ from the image data and the color image data C1 and C2 from the RGB / YCC conversion unit 5, for example, using the above-described formula. The generated image data R ', G', B '
Each is supplied to the photographic printing device 3.

The input unit 12 is provided for the operator to separately designate and input the modulation intensity of the high-frequency luminance image. The LUT 9 is configured to modulate the luminance high-frequency image with the input modulation intensity when the modulation intensity is designated and input from the input unit 12. This makes it possible to finely adjust the contrast of the main subject, which includes many high-frequency luminance images in the digital image. It is possible to obtain an image with contrast and saturation according to the operator's request.

Next, the operation of the image processing apparatus 2 according to the present embodiment will be described with reference to FIGS.

First, the image data RGB for each pixel from the film scanner 1 are color-converted and density-converted by the LUT 4, and then input to the RGB / YCC converter 5.
The RGB / YCC converter 5 creates the luminance image data Y and the color image data C1 and C2 (step 1;
Hereinafter, the step is simply abbreviated as S). The luminance image data Y is input to the LPF 6 and the subtractor 7, while the color image data C 1 and C 2 are input to the YCC / RGB converter 11.
Is input to

In the LPF 6, image data of a low-luminance image is created from the input luminance image data Y by the above-described mask processing, and is input to the subtractor 7 and the synthesizing unit 10 (S2). In the subtractor 7, RGB / YCC
The image data of the luminance low-frequency image from the LPF 6 is subtracted from the luminance image data Y from the conversion unit 5, and the image data of the luminance high-frequency image is created (S3). The image data is input to the intensity calculator 8 and the LUT 9.

The intensity calculator 8 calculates the modulation intensity based on the image data of the luminance high-frequency image by a method described later.
When the modulation intensity is input from the intensity calculation unit 8 to the LUT 9, the LUT 9 creates an LUT for modulating the image data of the high-frequency luminance image based on the modulation intensity (S4). The image data of the image is modulated by the LUT (S5).

Thereafter, the synthesizing section 10 synthesizes the image data of the modulated luminance high-frequency image obtained in S5 and the image data of the luminance low-frequency image obtained in S2, and obtains the luminance image data Y '. Is generated (S6). When the luminance image data Y ′ is input to the YCC / RGB converter 11, the YCC / RGB converter 11 converts the color image data C1 and C2 from the RGB / YCC converter 5 and the luminance image data Y ′. Based on image data R ', G', B '
Is generated and output to the photoprinting apparatus 3.

Next, the strength calculator 8 which is a feature of the present invention will be described. In the following, for convenience of explanation,
It is assumed that two main subjects are included in the original digital image, and the average values of the image data of the main subjects are 100 and 200, respectively. Therefore, when a histogram (first histogram) is created with the image data on the horizontal axis and the frequency on the vertical axis, this histogram becomes, for example, as shown by the solid line in FIG.
It is known that a figure having a maximum frequency at an average value of 100 or 200 of the image data is drawn. Therefore, a region in a desired range of the image data that includes each local maximum point is associated with a region in which the variance can be calculated in the histogram. (Embodiment 1) In the present embodiment, the intensity calculation unit 8
The case where the modulation intensity of the luminance high-frequency image is calculated based on the image data of the luminance high-frequency image from FIG.

The intensity calculation unit 8 creates a histogram (second histogram) indicating the relationship between the image data of the high-frequency luminance image included in the digital image and the frequency. Here, among the pixels located in one direction, the value (luminance value) of the luminance image data Y of each pixel depends on the pixel position in FIG.
If the image data of the luminance high-frequency image changes as shown by the solid line in (b), the image data of the blurred image indicated by the solid line, that is, the value obtained by subtracting the average of the luminance values from the luminance image data Y at each pixel (the same). For example, a in FIG.
b). Therefore, considering the above values including plus and minus signs (assuming the direction in which the difference is taken to be constant), the second histogram has an average luminance value as shown by the solid line in FIG. symmetrical about x,
In addition, a figure whose frequency is maximized at the average x of the luminance values is drawn. A region in a desired range of the image data including such a maximum point is associated with a region where variance can be calculated.

The high-frequency luminance image has an average luminance value x.
6C, the variance of the second histogram in FIG. 6C is eventually equal to the average value 100% of the image data of the main subject in the first histogram of FIG. 6A.
And the extent of the spread of the image data from 200. Therefore, the average x of the luminance values in FIG. 6C (for example, 0 in FIG. 6C) is the first luminance value in FIG.
This corresponds to the average values 100 and 200 of the image data of the main subject in the histogram.

Note that since the luminance high-frequency image frequently occurs in a portion of the digital image where a human easily feels a contrast (a portion where image data changes), when there are a plurality of main subjects in the digital image, The above-described second histogram is obtained for each main subject, and a composite of the above-described second histogram finally becomes a solid-line histogram.

[0110] Next, the intensity calculation unit 8 calculates the variance sigma ₁ ² by the solid line in the histogram. Here, variance sigma ₁ ² identifies that a degree scattered image data from the average value 100 (or 200) of the image data of the luminance high-frequency image, as described above, the smaller the variance sigma ₁ ^2, the main object contrast Is originally low, and conversely, if the variance σ ₁ ² is large, the contrast of the main subject is originally high. Incidentally, the variance sigma ² is the image data _{x 1, x 2, x 3} , ··· x N ( provided that, N
Is a natural number), and is generally expressed by the following equation (1).

[0111]

(Equation 1)

It should be noted that x in the expression ₁ represents image data x ₁ , x
₂ , x ₃ ,..., X _N , and is represented by the following equation (2).

[0113]

(Equation 2)

The intensity calculator 8 calculates the variance σ ₁ ²
But calculating the intensity such that the ideal variance sigma _R1 ² corresponding to the optimum contrast of the luminance high-frequency image by the modulation of the luminance high-frequency image. Ideal variance sigma _R1 ² above, for example, a value based on the experience of the operator or the like or a value recommended by the manufacturer on the basis of experiments or the like, it is set inputted in advance the strength in the computing unit 8, the operator Is set and input.

Thereafter, the LUT 9 creates an LUT based on the intensity, and modulates the luminance high-frequency image by the created LUT. Thus, a histogram of luminance high-frequency image of the modulated will have an ideal variance sigma _R1 ² corresponding to the optimum contrast. Thereafter, the synthesizing unit 10 synthesizes the modulated high-frequency image and low-frequency image, and reproduces a digital image.

As described above, in this embodiment, the variance of the second histogram of the luminance high-frequency image after the modulation is directly modulated by directly modulating the luminance high-frequency image itself which is largely contained in the main subject portion. An ideal dispersion corresponding to the optimum contrast is obtained. Since the low-frequency image of the digital image is constant before and after the modulation of the high-frequency luminance image, the first histogram of the digital image reproduced by the high-frequency luminance image after modulation and the low-frequency image (see the solid line)
Also becomes an ideal variance corresponding to the optimal contrast with the optimization of the luminance high-frequency image. That is, in the digital image with low contrast at the beginning, the skirt of the first histogram in the region including the local maximum point is widened, while in the digital image with high contrast, the width of the hem of the first histogram in the region is large. The narrowing results in an image with the optimal contrast finally.

Further, according to the present invention, in a digital image, only a high-frequency image in which humans can easily see the contrast is modulated. Appears as, for example, "sky" that does not contain much high-frequency images
And the contrast of the "cloud" part does not change much.

Therefore, when a photograph is printed based on the digital image after the synthesis, a high-quality photograph can be obtained in which the contrast of a portion (main subject) where humans easily feel the contrast is optimally expressed. In addition, before and after the modulation of the luminance high-frequency image, the image data value 100 when the first histogram takes the maximum point.
And 200 do not change, so that the average density of the main subject does not change, and the modulation of the high-frequency luminance image does not make the main subject entirely dark or bright.

Further, since the luminance high-frequency image of the digital image is often included in the edge portion of the image, the present invention has an effect that the edge portion can be enhanced and weakened by modulating the luminance high-frequency image. (Embodiment 2) Next, a case where the modulation intensity of a high-frequency luminance image is calculated based on the luminance image data Y from the RGB / YCC conversion unit 5 will be described.

In general, the difference between the adjacent pixels of the luminance image data Y directly corresponds to the magnitude of the contrast, and naturally increases in a digital image, for example, in a main subject portion where the image data changes to some extent. As a result, when a histogram (third histogram) including the difference between the adjacent pixels of the luminance image data Y and the frequency thereof is created, the third histogram becomes the image data corresponding to the average of the image data of the main subject portion. Difference x (for example, 0)
Is drawn symmetrically with respect to and a figure whose frequency is maximized by the difference x of the image data. Then, a region in a desired range of the difference in image data including such a maximum point is associated with a region in which variance can be calculated.
Therefore, the same effect as in the first embodiment can be obtained by adjusting the variance in the third histogram. Hereinafter, the specific method will be described.

For example, the luminance image data Y is the value shown in FIG. 7A for each pixel, and in FIG.
Assuming that the direction and the vertical direction are the Y direction, the intensity calculation unit 8 first calculates the difference in image data between pixels adjacent in the X direction, for example. In the example of FIG.
In the stage, 70−50 = 20, 50−80 = −30, 80
-100 = −20,... Similarly, in the second stage in the Y direction, 60−50 = 10, 50−1
00 = −50,... Are obtained, and at the third stage in the Y direction, 20−10 = 10, 10−50 = −40,.
・ Is obtained respectively.

Next, the intensity calculator 8 creates a third histogram with the difference between the image data obtained by the above calculation as the horizontal axis and the frequency as the vertical axis. Then, as shown by the solid line in FIG. 7B, the third histogram becomes maximum when the image data has a difference x, and is substantially bilaterally symmetric with respect to a vertical axis passing through the image data difference x. Note that the difference x between the image data is the difference x ₁ , x ₂ , x ₃ ,.
_XN (where N is a natural number) is an average value and can be obtained by the above equation (2).

[0123] Next, the intensity calculation unit 8 calculates the variance sigma ₂ ² by the solid line in histogram variance sigma ₂ ² described above, an ideal dispersion corresponding to the optimum contrast of the luminance high-frequency image by the modulation of the luminance high-frequency image calculating a strength such that the sigma _R2 ^2. Incidentally, the ideal variance sigma _R2 ² above, for example, if the value based on the experience of the operator or the like, or by the manufacturer is recommended values based on experiments or the like, are set inputted in advance the strength in the computing unit 8 Is set and input by the operator.

Thereafter, the LUT 9 creates an LUT based on the intensity, modulates the luminance high-frequency image with the created LUT, and combines the modulated high-frequency image with the original low-frequency image by the synthesizing unit 10. I do.

As described above, in the present embodiment, the luminance high-frequency image is modulated so that the variance of the third histogram is the variance corresponding to the optimal contrast of the luminance high-frequency image. When the digital image is reproduced by synthesizing the digital image with the low-frequency image, the average value of the image data of the main subject portion is 100 or 20 as in the first embodiment.
Image data of the digital image spreads around 0,
Alternatively, the main subject portion appears as an image with the optimal contrast.

Even if the variance of the third histogram is changed, the difference x of the image data when the maximum point is taken in the third histogram does not change. The average values 100 and 200 of the image data do not change. As a result, in the reproduced digital image, the main subject does not become brighter or darker as a whole. Therefore, according to the configuration of the present embodiment, the same effect as that of the first embodiment can be obtained.

In the above description, the histogram is created based on the difference between the image data in the X direction in FIG. 7, but the histogram may be created based on the difference between the image data in the Y direction. , The histogram may be created by adding the frequencies in both the X and Y directions.

Further, the difference between the image data may be obtained not at adjacent pixels but at two pixels located at positions sandwiching several pixels therebetween. When the resolution of a digital image is high, if the difference in image data between adjacent pixels is used, the difference in brightness may not be visible because the pixels are too close together. By taking the above, it is possible to reliably obtain a luminance difference and to cope with a high-resolution image.

In the first and second embodiments, each history
Variance of grams σ^TwoAnd the ideal variance σ _R ^TwoAnd based on strength
The degree is calculated, but 2σ^TwoAnd 2σ_R ^Two, 3σ^TwoAnd 3σ
_R ^TwoOf course, you can calculate the strength based on
Absent. Which combination is used is determined in advance by the strength calculation unit 8.
May be set to
The degree setting may be input.

In each of the methods of Embodiments 1 and 2 described above, the variance of the second histogram or the third histogram is changed so as to be the variance corresponding to the optimum contrast or the optimum saturation of the middle- and high-frequency components. By doing so, the variance of the first histogram is changed for each region in which the variance can be calculated so as to be the variance corresponding to the optimum contrast or the optimum saturation of the above-mentioned medium- and high-frequency components. Embodiment 2 Another embodiment of the present invention will be described below with reference to FIGS. For convenience of description, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 8, the image processing apparatus 2 ′ according to the present embodiment is different from the image processing apparatus 2 according to the first embodiment in that the subtractor 7, the intensity calculator 8, the LUT 9, and the synthesizer 1
0 is provided corresponding to each of the RGB image data, while the YCC / RGB converter 11 is omitted.

More specifically, in the present embodiment, the subtractor 7
Are composed of subtracters 7a, 7b and 7c corresponding to the respective RGB. Then, the RGB image data from the LUT 4 and the luminance low-frequency image image data from the LPF 6 are
The signals are input to the corresponding subtracters 7, respectively. As a result, the high-frequency image generated by the subtractor 7 is an image corresponding to each color of RGB.

The intensity calculator 8 and the LUT 9 also include intensity calculators 8a, 8b, 8c and LUTs corresponding to RGB.
9a, 9b, 9c, and converts high-frequency images into RGB
It can be modulated separately for each. Here, since the high-frequency image is an RGB image as described above, the intensity calculation unit 8 calculates the modulation intensity of the high-frequency image corresponding to the optimum saturation of the high-frequency luminance image for each RGB. The ideal variance of the second histogram or the third histogram used when calculating the modulation intensity is set and input to the intensity calculation unit 8 in advance.

The synthesizing unit 10 is composed of synthesizing units 10a, 10b, and 10c corresponding to the respective RGB.
High-frequency image and LPF modulated by T9a / 9b / 9c
The optimum R ′ image, the optimum G ′ image, and the optimum B ′ image are generated by synthesizing with the luminance low-frequency image from No. 6 and output to the photographic printing device 3.

In this embodiment, the color image data C
Since 1 · C2 is unnecessary, only the luminance image data Y is input to the LPF 6 from the RGB / YCC conversion unit 5. In FIG. 8, the RGB / YCC converter 5
Although the configuration is not such that the luminance image data Y from is input to the intensity calculation unit 8, such a configuration may be adopted as in the first embodiment. Further, in the present embodiment, a single input unit 12 enables designation input of the modulation intensity to each of the LUTs 9a, 9b, and 9c.

Next, the operation of the image processing apparatus 2 'will be described below with reference to FIGS.

First, after the image data RGB from the film scanner 1 is color-converted and density-converted by the LUT 4, it is input to the RGB / YCC converter 5 to create the luminance image data Y ( S11). Next, the luminance image data Y
Is input to the LPF 6, and the LPF 6 creates image data of a low-luminance image (S12). The image data is subtracted from the subtracters 7a, 7b, 7c and the combining units 10a, 10a.
b · 10c.

On the other hand, the image data RGB from the LUT 4
B is also input to the corresponding subtractors 7a, 7b, 7c. Accordingly, the subtractor 7a subtracts the image data of the luminance low-frequency image from the image data R (R original image) to create image data of the R high-frequency image (S13). The image data of the R high-frequency image is input to the intensity calculator 8a and the LUT 9a.

The intensity calculator 8a calculates the modulation intensity in the same manner as in the first or second embodiment (S14).
When this modulation intensity is input to the LUT 9a, the LUT 9a
An LUT for modulating the image data of the R high-frequency image is created based on the modulation intensity, and the image data of the R high-frequency image is modulated by the LUT (S1).
5).

Thereafter, in the synthesizing section 10a, the image data of the modulated R high-frequency image and the image data of the luminance low-frequency image obtained in S12 are synthesized, and the image data R ′ ( An optimal R ′ image) is generated (S16) and output to the photographic printing device 3.

On the other hand, in the subtractor 7b, the image data G (G
The image data of the G high-frequency image is created by subtracting the image data of the low-luminance image from the original image) (S17).
The image data of the G high-frequency image is input to the intensity calculator 8b and the LUT 9b.

The intensity calculator 8b calculates the modulation intensity in the same manner as in the first or second embodiment (S18).
When this modulation intensity is input to the LUT 9b, the LUT 9b
A LUT for modulating the image data of the G high frequency image is created based on the modulation intensity, and the LUT modulates the image data of the G high frequency image (S1).
9).

Thereafter, in the synthesizing section 10b, the image data of the modulated G high-frequency image and the image data of the luminance low-frequency image obtained in S12 are synthesized, and the image data G ′ ( An optimal G 'image) is generated (S20) and output to the photographic printing device 3.

In the subtractor 7c, the image data B (B
The image data of the B high-frequency image is created by subtracting the image data of the luminance low-frequency image from the original image) (S21).
The image data of the B high-frequency image is input to the intensity calculator 8c and the LUT 9c.

In the intensity calculator 8c, the modulation intensity is calculated in the same manner as in the first or second embodiment (S22).
When this modulation intensity is input to the LUT 9c, the LUT 9c
A LUT for modulating the image data of the B high-frequency image is created based on the modulation intensity, and the image data of the B high-frequency image is modulated by the LUT (S2).
3).

Thereafter, in the synthesizing unit 10c, the image data of the modulated B high-frequency image and the image data of the luminance low-frequency image obtained in S12 are synthesized, and the image data B ′ ( An optimal B ′ image) is generated (S24) and output to the photographic printing device 3.

As described above, in the present embodiment, since the high-frequency image is not a luminance image but an RGB image as in Embodiment 1, the high-frequency image is modulated and synthesized with the original low-frequency image. The saturation can be optimized only for a portion (main subject) of a digital image in which a human can easily sense contrast. Thereby, when a photograph is printed based on the digital image after the synthesis,
It is possible to obtain a high-quality photograph in which only the main subject portion optimally expresses the saturation. Moreover, since the value of the image data when the histogram takes the maximum point does not change before and after the modulation of the luminance high-frequency image, the average density of the main subject does not change. (For example, red) does not become brighter or darker.

Further, the input unit 12, for example, RG
By modulating the high-frequency image of a specific color of B while not modulating the high-frequency image of another color, the modulation intensity of the corresponding color is designated and input to each of the LUTs 9a, 9b, and 9c. In a digital image, only a portion including the specific color (or a plurality of specific colors) can be expressed intensely or weakly, and the contrast can be changed. [Third Embodiment] The following will describe still another embodiment of the present invention with reference to FIGS. For convenience of description, the same components as those in Embodiments 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 10, an image processing apparatus 2 ″ according to the present
Instead of omitting the B / YCC converter 5, an LPF 6 is provided corresponding to each RGB. That is, in the present embodiment, the LPF 6 is the LPF 6 corresponding to each RGB.
a, 6b, and 6c, and the image data RGB from the LUT 4 is input to the corresponding LPF 6. Accordingly, the LPFs 6a, 6b, and 6c respectively generate image data of low-frequency images of the corresponding colors. The image data of each low-frequency image from the LPF 6 is input to the subtractor 7 and the synthesis unit 10 of the corresponding color, respectively.

The subtractors 7a, 7b and 7c have LUs.
Since the image data R, G, and B from T4 are input, the subtracters 7a, 7b, and 7c output the image data R, G, and B, respectively.
By subtracting the image data of the low-frequency image of the corresponding color from G and B, the image data of the high-frequency image of the corresponding color is generated. Therefore, since the obtained high-frequency image is an RGB image as in the second embodiment, also in the present embodiment, the intensity calculation unit 8 calculates the modulation intensity corresponding to the optimum saturation of each high-frequency image for each RGB. Will be.

Next, the operation of the image processing apparatus 2 "will be described below with reference to FIGS.

First, the image data R, G, B from the film scanner 1 are color-converted and density-converted by the LUT 4, and then input to the corresponding LPF 6 and the subtractor 7. Thus, the LPF 6a creates image data of the R low-frequency image (S31). The image data is subtracted by a subtractor 7
a and the input to the synthesizing unit 10a.

In the subtractor 7a, the image data R (R original image)
Is subtracted from the image data of the R low-frequency image to create image data of the R high-frequency image (S32). The image data of the R high-frequency image is transmitted to the intensity calculator 8a and the LUT 9a.
Is input to

The intensity calculator 8a calculates the modulation intensity in the same manner as in the first or second embodiment (S33). When this modulation intensity is input to the LUT 9a,
An LUT for modulating the image data of the R high-frequency image is created based on the modulation intensity, and the image data of the R high-frequency image is modulated by the LUT (S34).

Thereafter, in the synthesizing section 10a, the image data of the modulated R high-frequency image and the R data obtained in S31 are obtained.
The image data of the low-frequency image is synthesized, and image data R ′ (optimal R ′ image) having the optimum contrast is generated (S
35), which is output to the photoprinting apparatus 3.

On the other hand, the image data G from the LUT 4
It is input to the PF 6b and the subtractor 7b. This allows
In the LPF 6b, image data of the G low-frequency image is created (S36), and this image data is input to the subtractor 7b and the combining unit 10b.

In the subtractor 7b, the image data G (G original image)
Is subtracted from the image data of the G low-frequency image to create image data of the G high-frequency image (S37). The image data of the G high-frequency image is transmitted to the intensity calculator 8b and the LUT 9b.
Is input to

The intensity calculator 8b calculates the modulation intensity in the same manner as in the first or second embodiment (S38). When this modulation intensity is input to the LUT 9b,
An LUT for modulating the image data of the G high frequency image is created based on the modulation intensity, and the LUT modulates the image data of the G high frequency image (S39).

Thereafter, in the synthesizing unit 10b, the image data of the modulated G high-frequency image and the G data obtained in S36 are obtained.
The image data of the low-frequency image is synthesized, and image data G ′ (optimal G ′ image) having the optimum contrast is generated (S
40), and output to the photoprinting apparatus 3.

The image data B from the LUT 4 is
It is input to the PF 6c and the subtractor 7c. This allows
In the LPF 6c, image data of the B low-frequency image is created (S41), and this image data is input to the subtractor 7c and the combining unit 10c.

In the subtractor 7c, the image data B (B original image)
Is subtracted from the image data of the B low-frequency image to create image data of the B high-frequency image (S42). The image data of the B high-frequency image is transmitted to the intensity calculator 8c and the LUT 9c.
Is input to

The intensity calculator 8c calculates the modulation intensity in the same manner as in the first or second embodiment (S43). When this modulation intensity is input to the LUT 9c,
An LUT for modulating the image data of the B high frequency image is created based on the modulation intensity, and the image data of the B high frequency image is modulated by the LUT (S44).

Thereafter, the image data of the modulated B high-frequency image and the B data obtained in S36 are obtained by the synthesizing unit 10c.
The image data of the low-frequency image is synthesized, and image data B ′ (optimal B ′ image) having the optimum contrast is generated (S
45), and is output to the photoprinting apparatus 3.

As described above, in the present embodiment, the high-frequency image to be modulated is an RGB image. Therefore, by modulating the high-frequency image and synthesizing it with the original low-frequency image, a human can easily feel the contrast in the digital image. The saturation of only the main subject can be optimized. Thereby, the same effect as in the second embodiment can be obtained.

The image processing described in each of the first to third embodiments is performed by an image processing apparatus 2 · 2 ′ as a computer.
A program to be executed by the 2 ”optical disk,
A configuration may be adopted in which recording is performed on a recording medium such as a magneto-optical disk or the like, and the image processing apparatuses 2, 2 ', and 2 "are automatically operated using such a recording medium.

[0166]

According to the first aspect of the present invention, there is provided an image processing apparatus comprising:
As described above, there is provided intensity calculation means for calculating the modulation intensity of the medium frequency / high frequency component corresponding to the optimum contrast or saturation of the medium frequency / high frequency component. This is a configuration for modulating components.

Therefore, the modulation intensity calculated by the intensity calculating means is an intensity corresponding to the optimum contrast or saturation of the intermediate frequency / high frequency component, and the low frequency component is constant before and after the modulation of the intermediate frequency / high frequency component. Therefore, when the modulating means modulates the medium-frequency / high-frequency component with the above-mentioned modulation intensity, and when the synthesizing means combines the modulated medium-frequency / high-frequency component with the original low-frequency component, For example, a main subject portion containing many medium-frequency and high-frequency components, which makes it easy for a human to visually sense the contrast, appears as an optimal contrast or an optimal saturation.

Therefore, according to the above configuration, when a photograph is printed based on the digital image after the synthesis, the contrast or the saturation of a portion where a human can easily feel the contrast is optimally expressed, and a high-quality photograph as a whole is obtained. This has the effect that it can be obtained. In addition, since the medium frequency and high frequency components of a digital image are often contained in the edge portion of the image, according to the above configuration, the edge portion can be emphasized and weakened by modulating the medium frequency and high frequency components. It also has the effect of being able to do so.

As described above, in the image processing apparatus according to the second aspect of the present invention, in the configuration of the first aspect, the intensity calculating means performs the modulation of the medium frequency / high frequency component for each pixel of the digital image. , The variance of the first histogram indicating the relationship between the image data and its frequency is the variance corresponding to the optimal contrast or the optimal saturation of the medium- and high-frequency components for each region where the variance can be calculated. This is a configuration for calculating the modulation intensity of the frequency / high frequency component.

Therefore, the variance of the first histogram in the digital image after the modulation of the mid-frequency and high-frequency components is determined by the modulation of the mid-frequency and high-frequency components. Since the variance corresponds to the contrast or the optimal saturation, the first histogram is obtained by centering on the average density of the main subject.
The medium- and high-frequency components expand and contract so as to have an optimum contrast or an optimum saturation. That is, the average density of the main subject does not shift. As a result, the main subject does not become entirely bright or dark due to the modulation of the medium frequency / high frequency components. Therefore, according to the above configuration, it is possible to achieve an optimum contrast or an optimum saturation in such a portion while maintaining the average density of the portion where the human can easily feel the contrast.

According to a third aspect of the present invention, as described above, in the configuration of the first or second aspect, the intensity calculating means performs the modulation of the intermediate frequency / high frequency component by modulating the intermediate frequency / high frequency component. The variance of the second histogram indicating the relationship between the image data for each pixel of the component and the frequency is
In this configuration, the modulation intensity of the intermediate frequency / high frequency component is calculated such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component.

Therefore, the medium frequency / high frequency component itself, which is largely contained in the main subject portion, is directly changed so that the variance of the second histogram becomes the variance corresponding to the optimum contrast or the saturation of the medium frequency / high frequency component. When the digital image is reproduced by synthesizing the medium-frequency and high-frequency components after modulation and the original low-frequency component, the main subject portion containing a large amount of such medium-frequency and high-frequency components will have the optimum contrast or Appears as an image with optimal saturation.

Even if the variance of the second histogram is changed, the average value of the image data of the main subject corresponding to the image data at the time when the maximum point is taken in the second histogram does not change. In the image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, there is an effect that optimum contrast or optimum saturation can be realized.

According to a fourth aspect of the present invention, as described above, in the configuration of the first or second aspect, the intensity calculation means performs image processing of the digital image by modulating the medium frequency / high frequency components. The variance of the third histogram showing the relationship between the difference between adjacent pixels of data and the frequency is
In this configuration, the modulation intensity of the intermediate frequency / high frequency component is calculated such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component.

Therefore, the intermediate frequency and high frequency components are modulated so that the variance of the third histogram becomes the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency and high frequency components. When a digital image is reproduced by synthesizing a high-frequency component and an original low-frequency component, the image data of the digital image spreads (or narrows) around the average value of the image data of the main subject portion, and the main subject portion is reduced. Appears as an image with optimal contrast or optimal saturation.

Even if the variance of the third histogram is changed, the average value of the image data of the main subject corresponding to the difference of the image data when the maximum point is taken in the third histogram does not change. In the digital image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, there is an effect that optimum contrast or optimum saturation can be realized.

According to a fifth aspect of the present invention, as described above, in addition to any one of the first to fourth aspects, a luminance based on image data corresponding to each of RGB colors of the digital image is provided. The image processing apparatus further includes a luminance image generating unit configured to generate an image, wherein the main component generating unit generates the low frequency component based on the luminance image and the medium frequency / high frequency based on the luminance image and the low frequency component. This is a configuration for generating components.

Therefore, the low-frequency component and the medium-frequency / high-frequency component generated by the main component generation means are a luminance low-frequency component and a luminance medium-frequency / high-frequency component, respectively. Therefore, the luminance (density) of the original digital image can be changed, for example, in a main subject portion by modulating the luminance middle frequency / high frequency component and then combining it with the luminance low frequency component. This has the effect that a digital image with the optimal contrast can be reliably obtained in the part where the contrast is easily felt.

The image processing apparatus according to the sixth aspect of the present invention, as described above, further comprises, in addition to any one of the first to fourth aspects, a luminance based on image data corresponding to each of the RGB colors of the digital image. The image processing apparatus further includes a luminance image generation unit that generates an image, wherein the main component generation unit generates the low frequency component based on the luminance image, and based on the image data and the low frequency component of the digital image. In this configuration, the medium-frequency and high-frequency components are generated for each of RGB.

Therefore, the low frequency component generated by the main component generation means becomes a luminance low frequency component, while the middle frequency and high frequency components become components corresponding to RGB colors. Therefore, by modulating the medium-frequency and high-frequency components of each color and combining them with the low-frequency components of the luminance, the saturation of the original digital image can be changed, for example, in the main subject portion, thereby enabling humans to obtain contrast. The effect is that a digital image with the optimal saturation can be reliably obtained in a part where the user can easily feel the image.

The image processing apparatus according to the seventh aspect of the present invention, as described above, according to any one of the first to fourth aspects, wherein the main component generation means includes an RG for the digital image.
The low-frequency component is generated for each of RGB based on the image data corresponding to each color of B, and the medium-frequency / high-frequency component is calculated based on the image data of the digital image and the low-frequency component of the corresponding color. This is a configuration that is generated for each of RGB.

Therefore, the low frequency component and the medium frequency / high frequency component generated by the main component generation means are
The digital image has a low-frequency component and a medium-frequency / high-frequency component corresponding to each color of RGB. Therefore, after modulating the medium-frequency and high-frequency components of each color, by combining with the low-frequency component of the corresponding color, the saturation of the original digital image can be changed, for example, in the main subject portion, This has the effect that a digital image with optimal saturation can be reliably obtained in a part where a human can easily feel contrast.

An image processing apparatus according to an eighth aspect of the present invention, as described above, further comprises an input means for designating and inputting the modulation intensity in any one of the first to seventh aspects. When the modulation intensity is designated and input by the input means, the medium frequency / high frequency component is modulated by the input modulation intensity.

Therefore, the modulation intensity can be separately designated and input by the input means, and the medium frequency and high frequency components can be modulated by the designated and input modulation intensity. This produces an effect that an image having an optimum saturation can be obtained.

Also, by separately inputting the modulation intensity by the input means, the contrast and saturation of the main subject can be finely adjusted, so that an image having the optimum contrast and optimum saturation is theoretically obtained. In addition, even when an image having the optimal contrast and the optimal saturation is not captured by the human eyes, an image having the optimal contrast and the optimal saturation can be reliably obtained by the human eyes.

Further, when the medium frequency and high frequency components are, for example, RG
When generated for each of the colors B, while modulating the medium- and high-frequency components of a specific color of RGB,
By specifying and inputting the modulation intensity of the corresponding color by the input means so as not to modulate the medium-frequency and high-frequency components of other colors, only the portion including the specific color in the digital image after synthesis is adjusted in saturation. It also has the effect of being able to do things.

As described above, the image processing method according to the ninth aspect of the present invention provides a low frequency component and a medium frequency
A first step of generating a high-frequency component for each pixel of the digital image; and a second step of calculating the modulation intensity of the intermediate-frequency / high-frequency component corresponding to the optimal contrast or the saturation of the intermediate-frequency / high-frequency component. A third step of modulating the medium-frequency / high-frequency component with the modulation intensity, and a fourth step of combining the modulated medium-frequency / high-frequency component with the original low-frequency component. Configuration.

Therefore, the medium-frequency and high-frequency components are modulated with the intensity corresponding to the optimum contrast and the optimum saturation of the medium-frequency and high-frequency components, and the low-frequency component is constant before and after the modulation of the medium-frequency and high-frequency components. Therefore, when the modulated medium-frequency / high-frequency component and the original low-frequency component are combined, the combined digital image contains many medium-frequency / high-frequency components that are easy for human eyes to see the contrast. The main subject portion appears with optimal contrast or optimal saturation.

Therefore, according to the above arrangement, when a photograph is printed based on the digital image after the synthesis, the contrast or the saturation of the portion where the human can easily feel the contrast is optimally displayed, and the high-quality photograph as a whole is obtained. This has the effect that it can be obtained. In addition, since the medium frequency and high frequency components of a digital image are often contained in the edge portion of the image, according to the above configuration, the edge portion can be emphasized and weakened by modulating the medium frequency and high frequency components. It also has the effect of being able to do so.

The image processing method according to the tenth aspect of the present invention
As described above, in the configuration according to the ninth aspect, the second step is a first histogram showing a relationship between image data for each pixel of the digital image and the frequency by modulating the medium frequency / high frequency component. Is a step of calculating the modulation intensity of the medium-frequency / high-frequency component such that the variance is a variance corresponding to the optimum contrast or the optimal saturation of the medium-frequency / high-frequency component for each region where the variance can be calculated. It is.

Therefore, the variance of the first histogram in the digital image after the modulation of the mid-frequency and high-frequency components is determined by the modulation of the mid-frequency and high-frequency components. Since the variance corresponds to the contrast or the optimal saturation, the first histogram is obtained by centering on the average density of the main subject.
The medium- and high-frequency components expand and contract so as to have an optimum contrast or an optimum saturation. That is, the average density of the main subject does not shift. As a result, the main subject portion does not become entirely bright or dark due to the modulation of the medium frequency / high frequency components. Therefore, according to the above configuration, it is possible to achieve an optimum contrast or an optimum saturation in such a portion while maintaining the average density of the portion where the human can easily feel the contrast.

The image processing method according to the eleventh aspect of the present invention
As described above, in the configuration according to claim 9 or 10, the second step is performed by modulating the medium-frequency / high-frequency component, and the relationship between the image data of each pixel of the medium-frequency / high-frequency component and the frequency thereof. Is the variance of the second histogram
The configuration is a step of calculating the modulation intensity of the medium-frequency / high-frequency component so that the variance corresponds to the optimum contrast or the saturation of the medium-frequency / high-frequency component.

Therefore, the medium frequency / high frequency component itself, which is largely contained in the main subject portion, is directly changed so that the variance of the second histogram is the variance corresponding to the optimum contrast or the optimum saturation of the medium frequency / high frequency component. When the digital image is reproduced by synthesizing the medium-frequency and high-frequency components after modulation and the original low-frequency component, the main subject portion containing a large amount of such medium-frequency and high-frequency components will have the optimum contrast or Appears as an image with optimal saturation.

Also, even if the variance of the second histogram is changed, the average value of the image data of the main subject corresponding to the image data at the time when the maximum point is taken in the second histogram does not change. In the image, the main subject part becomes bright overall,
It doesn't darken.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, there is an effect that optimum contrast or optimum saturation can be realized.

The image processing method according to the twelfth aspect of the present invention
As described above, in the configuration according to claim 9 or 10, the second step is performed by modulating the medium-frequency and high-frequency components, and the relationship between a difference between adjacent pixels of the image data of the digital image and its frequency. Is the variance of the third histogram
The configuration is a step of calculating the modulation intensity of the medium-frequency / high-frequency component so that the variance corresponds to the optimum contrast or the saturation of the medium-frequency / high-frequency component.

Therefore, the intermediate frequency / high frequency component is modulated so that the variance of the third histogram becomes the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. When a digital image is reproduced by synthesizing a high-frequency component and an original low-frequency component, the image data of the digital image spreads (or narrows) around the average value of the image data of the main subject portion, and the main subject portion is reduced. Appears as an image with optimal contrast or optimal saturation.

Further, even if the variance of the third histogram is changed, the average value of the image data of the main subject corresponding to the difference of the image data when the maximum point is taken in the third histogram does not change. In the digital image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, there is an effect that optimum contrast or optimum saturation can be realized.

The recording medium on which the image processing program according to the thirteenth aspect of the present invention is recorded has the first and second components for generating the low frequency component and the medium frequency / high frequency component of the digital image for each pixel of the digital image. And the above mid-frequency
A second process of calculating the modulation intensity of the intermediate frequency / high frequency component corresponding to the optimal contrast or the saturation of the high frequency component, a third process of modulating the intermediate frequency / high frequency component with the modulation intensity, An image processing program for causing a computer to execute a fourth process of synthesizing the obtained middle frequency / high frequency component and the original low frequency component is recorded.

Therefore, the medium-frequency and high-frequency components are modulated with an intensity corresponding to the optimum contrast and the optimum saturation of the medium-frequency and high-frequency components, and the low-frequency component is constant before and after the modulation of the medium-frequency and high-frequency components. Therefore, when the modulated medium-frequency / high-frequency component and the original low-frequency component are combined, the combined digital image contains many medium-frequency / high-frequency components that are easy for human eyes to see the contrast. The main subject portion appears with optimal contrast or optimal saturation.

Therefore, according to the above configuration, a computer (for example, an image processing apparatus) is executed by using a recording medium on which a program for executing such image processing is recorded, and based on a digital image reproduced by the computer. When a photograph is printed, there is an effect that only parts where a human can easily feel the contrast optimally express the contrast or saturation to obtain a high-quality photograph as a whole. In addition, since the medium frequency and high frequency components of a digital image are often contained in the edge portion of the image, according to the above configuration, the edge portion can be emphasized and weakened by modulating the medium frequency and high frequency components. It also has the effect of being able to do so.

According to a fourteenth aspect of the present invention, as described above, in the recording medium storing the image processing program according to the thirteenth aspect, the second processing is performed by modulating the medium frequency / high frequency component. The variance of the first histogram indicating the relationship between the image data of each pixel of the digital image and the frequency is calculated for each of the regions for which the variance can be calculated.
The configuration is a process of calculating the modulation intensity of the medium frequency / high frequency component such that the variance corresponds to the optimal contrast or the optimal saturation of the high frequency component.

Therefore, the variance of the first histogram in the digital image after the modulation of the mid-frequency and high-frequency components is determined by the modulation of the mid-frequency and high-frequency components. Since the variance corresponds to the contrast or the optimal saturation, the first histogram is obtained by centering on the average density of the main subject.
The medium- and high-frequency components expand and contract so as to have an optimum contrast or an optimum saturation. That is, the average density of the main subject does not shift. As a result, the main subject portion does not become entirely bright or dark due to the modulation of the medium frequency / high frequency components. Therefore, according to the above configuration, it is possible to achieve an optimum contrast or an optimum saturation in such a portion while maintaining the average density of the portion where the human can easily feel the contrast.

[0207] According to a fifteenth aspect of the present invention, as described above, in the recording medium storing the image processing program according to the thirteenth or fourteenth aspect, the second processing is performed by modulating the medium frequency / high frequency components. The variance of the second histogram indicating the relationship between the image data of each pixel of the medium frequency / high frequency component and its frequency is a variance corresponding to the optimal contrast or the optimal saturation of the medium frequency / high frequency component. , Which is a process for calculating the modulation intensity of the medium frequency / high frequency component.

Therefore, the medium frequency / high frequency component itself, which is largely contained in the main subject portion, is directly changed so that the variance of the second histogram is the variance corresponding to the optimum contrast or the optimum saturation of the medium frequency / high frequency component. When the digital image is reproduced by synthesizing the medium-frequency and high-frequency components after modulation and the original low-frequency component, the main subject portion containing a large amount of such medium-frequency and high-frequency components will have the optimum contrast or Appears as an image with optimal saturation.

Even if the variance of the second histogram is changed, the average value of the image data of the main subject corresponding to the image data at the time when the maximum point is taken in the second histogram does not change. In the image, the main subject part becomes bright overall,
It doesn't darken.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, there is an effect that optimum contrast or optimum saturation can be realized.

[0211] In the recording medium storing the image processing program according to the sixteenth aspect of the present invention, as described above, in the configuration of the thirteenth or fourteenth aspect, the second processing is performed by modulating the medium frequency / high frequency component. The variance of the third histogram indicating the relationship between the difference between the adjacent pixels of the image data of the digital image and the frequency thereof becomes the variance corresponding to the optimum contrast or the optimum saturation of the medium frequency / high frequency components. , Which is a process for calculating the modulation intensity of the medium frequency / high frequency component.

Therefore, since the intermediate frequency / high frequency component is modulated so that the variance of the third histogram becomes the variance corresponding to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component, the modulated intermediate frequency / high frequency component is modulated. When a digital image is reproduced by synthesizing a high-frequency component and an original low-frequency component, the image data of the digital image spreads (or narrows) around the average value of the image data of the main subject portion, and the main subject portion is reduced. Appears as an image with optimal contrast or optimal saturation.

Even if the variance of the third histogram is changed, the average value of the image data of the main subject corresponding to the difference of the image data when the maximum point is taken in the third histogram does not change. In the digital image, the main subject does not become brighter or darker as a whole.

Therefore, according to the above configuration, while maintaining the average density of the part where the human can easily feel the contrast,
In such a portion, there is an effect that optimum contrast or optimum saturation can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an image processing apparatus according to an embodiment of the present invention and a digital exposure system including the image processing apparatus.

FIG. 2 is an explanatory diagram showing a configuration example of a moving average filter as an LPF of the image processing apparatus.

FIG. 3A is an explanatory diagram illustrating an example of image data of each pixel, and FIG. 3B is a diagram illustrating image data of each pixel when image data of a target pixel is converted by a median filter serving as the LPF. FIG.

FIG. 4 is an explanatory diagram showing a configuration example of a Gaussian filter as the LPF.

FIG. 5 is a flowchart showing a flow of an operation in the image processing apparatus.

FIG. 6A is an explanatory diagram illustrating a relationship between image data obtained for each pixel of a digital image and its frequency.
FIG. 3B is an explanatory diagram illustrating a change in a luminance value of a pixel located in one direction. FIG. 3C is an explanatory diagram showing a relationship between image data of a high-frequency luminance image included in the digital image and its frequency.

FIG. 7A is an explanatory diagram illustrating an example of image data for each pixel of the digital image. FIG. 4B is an explanatory diagram showing a relationship between a difference in image data between adjacent pixels of the digital image and the frequency thereof.

FIG. 8 is a block diagram illustrating a schematic configuration of an image processing apparatus according to another embodiment of the present invention and a digital exposure system including the image processing apparatus.

FIG. 9 is a flowchart showing a flow of an operation in the image processing apparatus.

FIG. 10 is a block diagram showing a schematic configuration of an image processing apparatus according to still another embodiment of the present invention and a digital exposure system including the image processing apparatus.

FIG. 11 is a flowchart showing a flow of an operation in the image processing apparatus.

FIG. 12 is a block diagram illustrating a schematic configuration of a conventional image processing apparatus capable of adjusting the saturation of a digital image.

FIG. 13 is a block diagram illustrating a schematic configuration of a conventional image processing apparatus capable of enhancing an outline in an image.

[Explanation of symbols]

 2.2 ′ 2 ″ image processing device 5 RGB / YCC converter (luminance image generating means) 6.6a ・ 6b ・ 6c LPF (main component generating means) 7.7a ・ 7b ・ 7c subtractor (main component generating means) 8.8a / 8b / 8c intensity calculation unit (intensity calculation unit) 9.9a / 9b / 9c LUT (modulation unit) 10.10a / 10b / 10c synthesis unit (synthesis unit) 12 input unit (input unit)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/79 H04N 9/79 H (72) Inventor Minoru Uchida 11-30 Enomachi, Suita-shi, Osaka F-term in Toyo Information System Co., Ltd. (reference) 5B057 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC03 CE06 CE08 CE16 DB02 DB06 DB09 DC19 DC30 5C021 PA33 PA34 PA35 PA39 PA66 PA77 PA80 XA35 XB02 XB17 ZA01 5C055 AA14 BA0019EA05 HA05 PP01 PP15 PP23 PP27 PP28 PP31 PP32 PP34 PP37 PP46 PP47 PP49 PQ01 PQ12 PQ18 PQ19 PQ23 SS05 TT09 5C079 HB01 HB04 LA12 LA14 LA15 LA40 LB01 MA04 MA11 MA19 NA03

Claims (16)

[Claims] A low frequency component and a medium frequency component of a digital image.
A main component generating means for generating a high frequency component for each pixel of the digital image; a modulating means for modulating the medium frequency / high frequency component; and combining the modulated medium frequency / high frequency component with the original low frequency component. And an intensity calculating means for calculating a modulation intensity corresponding to an optimum contrast or an optimum saturation of the intermediate frequency and high frequency components, wherein the modulation means calculates the modulation intensity with the modulation intensity. An image processing apparatus for modulating the medium-frequency and high-frequency components. 2. The variance of the first histogram indicating the relationship between the image data of each pixel of the digital image and the frequency by the modulation of the medium frequency / high frequency component. For each area,
2. The image processing apparatus according to claim 1, wherein the modulation intensity of the medium-frequency / high-frequency component is calculated so that the variance corresponds to the optimal contrast or the optimal saturation of the high-frequency component. 3. The method according to claim 2, wherein the modulation of the medium frequency and high frequency components causes the variance of the second histogram indicating the relationship between the image data of each pixel of the medium frequency and high frequency components and the frequency thereof to be changed. 3. The image processing apparatus according to claim 1, wherein the modulation intensity of the intermediate frequency / high frequency component is calculated such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. 4. The method according to claim 1, wherein the modulation of the medium frequency / high frequency component causes the variance of a third histogram indicating a relationship between a difference between adjacent pixels of the image data of the digital image and its frequency to be changed. 3. The image processing apparatus according to claim 1, wherein the modulation intensity of the intermediate frequency / high frequency component is calculated such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. 5. The image processing apparatus according to claim 1, further comprising: a luminance image generating unit configured to generate a luminance image based on image data corresponding to each of RGB colors of the digital image. The image processing apparatus according to any one of claims 1 to 4, wherein the image processing apparatus generates the medium frequency and high frequency components based on the luminance image and the low frequency components. 6. A luminance image generating means for generating a luminance image based on image data corresponding to each of RGB colors of the digital image, wherein the main component generating means comprises a low frequency component based on the luminance image. The image according to any one of claims 1 to 4, wherein the intermediate frequency and the high frequency components are generated for each of RGB based on the image data of the digital image and the low frequency components. Processing equipment. 7. The main component generation means generates the low frequency component for each of RGB based on image data corresponding to each color of RGB of the digital image, and corresponds to each image data of the digital image. The image processing apparatus according to any one of claims 1 to 4, wherein the medium frequency / high frequency component is generated for each of RGB based on a low frequency component of a color. 8. An input means for designating and inputting the modulation intensity, wherein the modulation means, when the modulation intensity is designated and input by the input means, uses the inputted modulation intensity to output the intermediate frequency signal.
The image processing apparatus according to claim 1, wherein the high frequency component is modulated. 9. A low frequency component and a medium frequency component of a digital image.
A first step of generating a high-frequency component for each pixel of the digital image; and a second step of calculating the modulation intensity of the intermediate-frequency / high-frequency component corresponding to the optimal contrast or the saturation of the intermediate-frequency / high-frequency component. And a third step of modulating the medium frequency / high frequency component with the modulation intensity.
And a fourth step of synthesizing the modulated medium- and high-frequency components and the original low-frequency component. 10. The variance of a first histogram indicating a relationship between image data of each pixel of the digital image and its frequency by modulating the medium frequency / high frequency component is calculated by the second step. For each possible area,
The image processing method according to claim 9, further comprising a step of calculating the modulation intensity of the intermediate frequency / high frequency component such that the variance corresponds to the optimal contrast or the optimal saturation of the high frequency component. 11. The method according to claim 11, wherein the modulating of the medium frequency and high frequency components causes the variance of a second histogram indicating the relationship between the image data of each pixel of the medium frequency and high frequency components and the frequency thereof to be: The method according to claim 9, wherein the step of calculating a modulation intensity of the medium-frequency / high-frequency component such that a variance corresponding to an optimum contrast or an optimal saturation of the medium-frequency / high-frequency component is performed. Image processing method. 12. The method according to claim 12, wherein the variance of a third histogram indicating a relationship between a difference between adjacent pixels of the image data of the digital image and its frequency is obtained by modulating the medium frequency / high frequency components. The method according to claim 9, wherein the step of calculating a modulation intensity of the medium-frequency / high-frequency component such that a variance corresponding to an optimum contrast or an optimal saturation of the medium-frequency / high-frequency component is performed. Image processing method. 13. A first process for generating a low-frequency component and a medium-frequency / high-frequency component of a digital image for each pixel of the digital image, and a process corresponding to the optimum contrast or optimal saturation of the medium-frequency / high-frequency component. A second process for calculating the modulation intensity of the intermediate frequency / high frequency component, and a third process for modulating the intermediate frequency / high frequency component with the modulation intensity.
And a fourth process for synthesizing the modulated medium-frequency / high-frequency component and the original low-frequency component on a recording medium storing an image processing program for causing a computer to execute the process. 14. The second process calculates a variance of a first histogram indicating a relationship between image data of each pixel of the digital image and its frequency by modulating the medium-frequency and high-frequency components. For each possible area,
14. The image processing program according to claim 13, wherein the processing is for calculating the modulation intensity of the medium-frequency / high-frequency component such that the variance corresponds to the optimal contrast or the optimal saturation of the high-frequency component. recoding media. 15. The variance of a second histogram indicating a relationship between image data of each pixel of the intermediate frequency / high frequency component and its frequency by modulating the intermediate frequency / high frequency component, The method according to claim 13 or 14, wherein the processing is a process of calculating the modulation intensity of the intermediate frequency / high frequency component such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. A recording medium on which an image processing program is recorded. 16. The method according to claim 16, wherein the variance of the third histogram indicating the relationship between the difference between adjacent pixels of the image data of the digital image and the frequency is obtained by modulating the medium frequency / high frequency components. The method according to claim 13 or 14, wherein the processing is a process of calculating the modulation intensity of the intermediate frequency / high frequency component such that the variance corresponds to the optimal contrast or the optimal saturation of the intermediate frequency / high frequency component. A recording medium on which an image processing program is recorded.