JPH06139323A - Method and system for picture processing capable of faithful reproduction of object color from negative film - Google Patents

Abstract

PURPOSE:To faithfully reproduce the color of an object with a color film and a digital picture processor which have a simple constitution by processing the color correction by the digital picture processor independent of the color film. CONSTITUTION:The picture fixed to a basic negative 100 is converted to R, G, and B analog video signals with one picture element as the unit by a scanner 101. R, G, and B analog video signals from the scanner 101 are supplied to a demodulation processing part 102 to obtain a colorimetric signal. The demodulation processing part 102 supplies this colorimetric signal to a picture processing part 103. This part 103 converts the supplied colorimetric signal to color information of primary colors of a phosphor of a color CRT and subjects it to aesthetical color correction if necessary and supplies it to a monitor device like a color CRT 104 to display a picture where the hue of the object is faithfully reproduced. Further, the picture processing part 103 supplies color information subjected to aesthetical color correction to an output circuit 105 for hard copy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing system and an image processing method capable of digitally image-processing an image recorded on a color negative film to obtain a subject image in which colors are faithfully reproduced.

[0002]

2. Description of the Related Art In a color photograph, it is desirable to reproduce a color (hue) close to a human impression. Spectral sensitivity of color film plays an important role in faithful color reproduction. As an ideal spectral sensitivity, the spectral sensitivity based on the color sensitivity to human light shown in FIG. 1 is known. The spectral sensitivities of blue, green and red are close to each other, and further have a large negative sensitivity in the wavelength region of 490 nm to 530 nm.

[0003]

If the spectral sensitivity corresponding to the color sensitivity shown in FIG. 1, particularly the negative sensitivity is to be realized only by the color film, the structure of the color film becomes very complicated. Further, there is a limit to the chemical image processing that can be performed with a color film, and it is practically impossible to accurately realize the spectral sensitivity corresponding to the color sensitivity of FIG.

Therefore, the image pickup function and the color correction (color reproduction) function of the conventional color film are separated so that the color film mainly shares the image pickup function, and the color correction function is independent from the color film. It is conceivable to let the digital image processing device which has been set up take charge. This method greatly simplifies the construction of the film as it eliminates the need for color correction. Further, it is expected that the use of the digital image processing device will improve the accuracy and the degree of freedom of color correction and facilitate the processing of images.

The present invention has been made in view of the above circumstances, and provides an image processing system and method capable of faithfully reproducing the color of an object by using a color film and an image processing apparatus having a simple structure. With the goal.

[0006]

In order to achieve the above object, an image processing apparatus according to the present invention includes an input conversion means for reading an image of a subject fixed on a film and converting it into a corresponding signal, and an input conversion means. Connected to the demodulation means for demodulating the color measurement signal indicating the color measurement information of the subject in response to this signal, and connected to the demodulation means, based on the color measurement signal,
The output means outputs an image having substantially the same hue as the subject.

The film used in the image processing system of the present invention includes, for example, cyan, magenta, and
It includes three light-sensitive layers that develop one corresponding color of yellow, the colorimetric quality factor of the spectral sensitivity of the light-sensitive layers is 0.9 or more, and it does not include colored couplers and DIR couplers.

According to the image processing method of the present invention, cyan, magenta, and yellow are colored in accordance with the exposure amount, and the spectral sensitivities are all positive values. The quality coefficient indicates the degree of coincidence between the spectral sensitivity and human color sensitivity. Of 0.9 or more, the subject image is fixed on the film, the subject image on the film is converted into corresponding image data, the subject color information is demodulated from the image data, and the color information And outputting an image having substantially the same color as the subject based on the above.

[0009]

In the above structure, the input conversion means is, for example,
It is composed of a scanner or the like that scans a film to read an image, and converts the image into a corresponding RGB video signal.

The demodulating means converts this video signal into an integrated density of the object by referring to a predetermined conversion table obtained in advance using a calibration wedge or the like, and the integrated density has a predetermined 3 rows and 3 columns. Matrix operation is applied to convert into analysis concentration,
This analytical density is converted into an exposure density based on the characteristic curve of the film, and a predetermined index calculation is performed using this exposure density to obtain an exposure transmittance, and a matrix calculation of a predetermined 3 rows and 3 columns is performed on this exposure transmittance. To reproduce the colorimetric information of the subject. This colorimetric information is the so-called appearance value.
ance value), which faithfully represents the hue of the subject.

Further, the demodulating means uses the correspondence information (table, arithmetic expression, etc.) between the analytical density and the exposure density stored in advance in the storage means when converting the analytical density into the exposure density. Here, the exposure density is obtained from a reference image previously recorded in a predetermined area outside the photographing screen of the color film, and further, based on the exposure density of the reference image, the correspondence information of the storage means, the analysis density of the film to be processed, and the exposure. The shift in correspondence with the density may be corrected. If such a process is performed, the change in the color film before and after the processing, for example, the wetness and heat change of the unphotographed film, the latent image change of the photographed film, the process variation, the fading of the image after the process, and the manufacturing failure of the photosensitive material are caused. Even if there is uniformity, the color of the subject can be faithfully reproduced.

The output means is composed of, for example, a display device, a color printer, etc., and aesthetically corrects the colorimetric signal from the demodulation means, if necessary, and then performs matrix operation of 3 rows and 3 columns. The three primary colors used for image display (for example, the colors of the RGB phosphors of the color CRT) are converted into colorimetric signals, and the image is displayed in accordance with the colorimetric signals. Also, the colorimetric signal is logarithmically converted, and the colorimetric signal after the logarithmic conversion is subjected to a predetermined matrix calculation of 3 rows and 3 columns to obtain a colorant signal indicating the density of the colorant, and the color printer outputs the colorant signal to To form an image.

Since the film used in the image processing system of the present invention has a colorimetric quality coefficient of spectral sensitivity of 0.9 or more, it is possible to obtain the necessary and sufficient color information of the subject. Further, since the color coupler is not included, the S / N ratio can be increased when the film is read by the input conversion means such as the scanner. Further, since no DIR coupler is included, the structure of the film is simplified and at the same time, the latter half image processing can be performed easily and accurately.

According to the image processing method of the present invention,
The hue (colorimetric color information) of the subject can be fixed on the film relatively faithfully, and the data read from the film can output an image having substantially the same color as the subject.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image processing system according to an embodiment of the present invention will be described below.

(Description of Principle) First, the principle of this embodiment will be described.

Any color light can be equalized by appropriately mixing the three color lights of red, green and blue. Monochromatic light of wavelength λ having unit energy [λ] is [R] color light, [G] color light,
If the [B] colored lights are color-matched when mixed at a ratio of r, g, and b, this relationship can be expressed as follows.

1 [λ] = r [R] + g [G] + b [B] (1) Mixing ratios r, g, and b represent R, G, and B components in the monochromatic light [λ]. By continuously changing the wavelength of monochromatic light in the visible wavelength range, the mixing ratios r, g, and b can be obtained as a function of wavelength. The functions r (λ), g (λ), and b (λ) show visual responsiveness, are called color matching functions, and are equal to the human color sensitivity shown in FIG.

The ideal spectral sensitivity of a color film is this color matching function. However, since it is difficult to realize the negative sensitivity of the color matching function in the color film, the color matching functions r (λ), g (λ), and b (λ) cannot be directly adopted as the spectral sensitivity. . Therefore, the color matching function r
(Λ), g (λ), and b (λ) are mathematically transformed by the equation (2), and the functions u (λ) and v are all positive values.
(Λ) and w (λ) are derived and used as the spectral sensitivity.

[0020]

[Equation 1] The primary color in this case (hereinafter referred to as the primary stimulus) is a primary color that does not actually exist (imaginary color primary color), but the matrix element Cij uses the three primary colors (color light) of the color photograph to match these virtual primary colors. The required mixing ratio is shown.

If these functions u (λ), v (λ) and w (λ) are adopted as the spectral sensitivity of the color film, the exposure transmittances (relative exposure amounts with respect to the white point) Tu, Tv, Tw.
Is expressed by equation (3). However, P (λ) represents the energy distribution of the light source, and ρ (λ) represents the spectral reflectance of the subject.
By substituting equation (2) into equation (3) and rearranging, equation (4) is obtained.

[0022]

[Equation 2] The integral on the right side of the equation (4) indicates the tristimulus value of the subject. If this is represented by R, G, and B, the equation (5) is obtained. By solving the equation (5) for R, G, and B, the equation (6) is obtained.

[0023]

[Equation 3] The expression (6) means that a color matching function consisting of all positive values is adopted as the spectral sensitivity of the color film, and a predetermined matrix of 3 rows and 3 columns is calculated for the exposure transmittance recorded at that time. This means that the tristimulus values R, G, B (appearance value, appearance value) of the subject can be restored.

Therefore, in this embodiment, as the color negative film, one having only the positive spectral sensitivity as shown in FIG. 2 is adopted, and the image obtained by this color negative film is converted into an electric signal, and (3) The conversion shown in the equation (6) is performed by the digital image processing device to restore the tristimulus values R, G, B of the subject.

The tristimulus values R, G and B of the subject obtained as described above are obtained by using the three primary colors of the color photograph as the primary stimuli. This numerical value can be easily converted into a tristimulus value using another primary color as a primary stimulus. So, for example, when displaying an image on a basic negative on a color CRT, a color CR
The color of the phosphor of T becomes the primary stimulus, and the color CR at that time
The tristimulus values R _CR , G _CR and B _CR of T can be obtained by the equation (7). By displaying an image on a color CRT using the tristimulus values R _CR , G _CR , and B _CR , it is possible to display a subject image in which colors (hues) are relatively faithfully reproduced.

[0026]

[Equation 4] Here, the matrix coefficient Dij is a coefficient when the primary color of the CRT is represented by the sum of the three primary colors of the subject, and can be obtained by experiment.

Similarly, it is possible to make a hard copy of the image of the subject using the tristimulus values R, G, B of the subject. For example, when a subject image is fixed by a color laser printer, the tristimulus values R, G, B of the subject need to be converted into color material signals (c, m, y) of color paper. Assuming that the color material of the color paper is a block dye having an ideal absorption characteristic shown by the broken line in FIG. 2, (8)
The formula holds.

[0028]

[Equation 5] Since the integration on the right side of equation (8) indicates the tristimulus value of the white point,
If it is expressed by R0, G0, and B0, the equation (8) can be rewritten as the equation (9). By further transforming equation (9), equation (10) is derived.

[0029]

[Equation 6] The color material of the actual color paper is not a block dye,
As shown by the solid line in FIG. 2, a smooth absorption curve having a hypotenuse is shown. This can be approximately regarded as a block dye having side absorption. Therefore, the actual density of the color material is c *,
If m * and y *, the relationship of the equation (11) is approximately established between the block dye concentrations c, m, and y. further,
By substituting equation (11) into equation (10) and rearranging, equation (12) is obtained.

[0030]

[Equation 7] Here, the coefficient fij (i and j are not equal) shows the ratio of the sub-absorption concentration to the main concentration, and the coefficient fij (i = j) shows the main concentration.

The density c of the coloring material obtained by the equation (12)
By giving *, m *, and y * to the color laser printer, an image in which the color of the subject is faithfully reproduced can be formed on the color paper.

(Structure of Embodiment) Next, the structure of the image processing system of this embodiment will be described in detail.

First, the color negative film (basic negative) used in this embodiment will be described.

In this embodiment, the basic negative is
It is for fixing the colorimetric information of the subject, and adopts an extremely simple configuration that consists only of essential items. That is, the negative of this example does not include (a) a colored coupler (orange mask) or a DIR coupler unlike a normal color negative, (b) is composed of three photosensitive layers, and (c) is spectral sensitivity of each photosensitive layer. Is as close to a color matching function as possible (all positive values), and (d) one of cyan (C), magenta (M), and yellow (Y) is developed in accordance with the exposure amount of each photosensitive layer. And

The colored coupler has a function of preventing the color from becoming turbid when a print is produced by a usual enlarger. However, in the present embodiment, when the basic negative is read by the scanner, the light amount is attenuated and the S / N ratio is deteriorated. Therefore, the basic negative is not included.

DIR (Dvelopment Inhibitor Rel)
easing) couplers are couplers that release development inhibitors. With this coupler, depending on the color of the subject,
Since the shape of the characteristic curve changes, it is not possible to determine which curve should be used as the conversion curve when converting the exposure density through the characteristic curve. So the basic negative is D
The structure does not include an IR coupler.

When it is attempted to realize the negative spectral sensitivity with the basic negative, the structure of the basic negative becomes complicated. Therefore, in this embodiment, the spectral sensitivity of each photosensitive layer of the basic negative takes only a positive value. When a color that looks different with the eyes is recorded as the same color on the negative, no matter how much digital image processing is performed thereafter, accurate hue reproduction is impossible. Therefore, the spectral sensitivity of each photosensitive layer of the basic negative is set as close as possible to the color matching function of FIG.

An example of the spectral sensitivity of the basic negative is shown in FIG. A colorimetric quality coefficient (also referred to as q-factor) is known as an evaluation scale showing how close the spectral sensitivity is to the color matching function of FIG. When the value of this scale is 1.0, it means that they are completely in agreement, and when it is 0.9 or more, the similarity is very high. The q factor of the basic negative having the spectral sensitivity shown in FIG. 3 is 0.94 for the red photosensitive layer, 0.98 for the green photosensitive layer, and 0.93 for the blue photosensitive layer. It can be evaluated as being close to a function.

(Structure of Image Processing Apparatus) Next, the structure of the image processing unit according to this embodiment will be described with reference to FIGS.

First, the overall structure will be described with reference to FIG.

The image fixed on the basic negative 100 is converted into R, G, B video analog signals for each pixel by using the scanner 101. As the scanner 101, for example, SG-1000A manufactured by Dainippon Screen Co., Ltd. can be used.

The R, G, B analog video signals from the scanner 101 are supplied to the demodulation processing unit 102. The demodulation processing unit 102 performs analog-to-digital conversion on the R, G, B analog video signals, performs digital calculations on them, and colorimetric signals indicating the tristimulus values R, G, B of the subject. To get

The demodulation processing unit 102 supplies this colorimetric signal to the image processing unit 103. The image processing unit 103 uses the tristimulus values R, G, B of the subject indicated by the supplied colorimetric signal as tristimulus values R _CR whose primary colors are the colors of the phosphors of the color CRT,
G _CR, converted to B _CR, subjected to aesthetic color correction as required, and supplies to the monitor device, such as a color CRT 104, and displays the faithfully reproduced image hue of the object. further,
The image processing unit 103 uses the tristimulus value R with aesthetic color correction.
_CR , G _CR , and B _CR are reconverted into the tristimulus values R, G, and B of the subject and supplied to the output circuit 105 for hard copy.

The output circuit 105 selects a color material signal in response to the tristimulus values R, G, B, calibrates the color material signal as necessary, and supplies it to the color printer 106. The color printer 106 forms a subject image that faithfully reproduces the hue of the subject on color paper according to the color material signal supplied from the output circuit 105.

Next, referring to FIG. 5, the demodulation processing unit 102
A configuration of the demodulation processing unit 102A will be described. R, G, B analog video signals from the scanner 101 are A / D
It is converted into R, G, B digital video signals by the converter 201 and supplied to the integrated density conversion circuit 202.

The memory 207 stores the R, G, B digital image signals and the R, G, B shown in FIG.
Save the conversion table for. This conversion table is obtained in advance by an experiment using a calibration density wedge, for example. The density converter 202 refers to this conversion table and converts the R, G, B digital video signals into corresponding densities (integrated densities) DR, DG, DB.

The integrated densities DR, DG and DB are inconvenient for analysis. Therefore, the maritrix calculation unit 203 performs the matrix calculation shown in Expression (13) on the output of the converter 202 using the matrix coefficient stored in advance in the matrix coefficient memory 208, and calculates the integrated density as the analytical density (color development). Concentration) D
Convert to C, DM, DY. The coefficient bij forming the matrix used for this conversion shows the ratio of the sub-absorption concentration to the main concentrations DC, DM, and DY of the three coloring materials used in the basic negative, and the sub-absorption concentration is measured by an experiment. Required by

[0048]

[Equation 8] Analysis density D output from the matrix calculation circuit 230
C, DM, and DY are supplied to the exposure density conversion circuit 204. The exposure density conversion circuit 204 stores the analysis densities DC, DM and DY stored in the table memory 209 and the exposure densities Dr,
The supplied analysis densities DC, DM, DY are compared with the exposure densities Dr, Dg, D by referring to the table showing the relationship between Dg, Db.
b, and supplies this to the exponential conversion circuit 205.

The relationship between the analysis densities DC, DM, DY of the respective photosensitive layers and the exposure densities (exposure doses) Dr, Dg, Db is a characteristic peculiar to the photosensitive material (referred to as characteristic curve), and is usually a sensitivity meter (sensitometer). ) And so on. However, since the characteristic curve when a scene is actually shot is often different from the characteristic curve obtained by the sensitometer due to the influence of camera flare, the demodulation processing unit 102A uses a camera-through characteristic curve. The characteristic curve of this camera through can be obtained by plotting the relationship between the exposure density and the analysis density for the six achromatic colors of Macbeth Color Checker which are copied on the frame actually photographed as shown in FIG. In the basic negative of the present embodiment, since the shape of the characteristic curve does not change depending on the color of the subject (that is, depending on the color development ratio of the three photosensitive layers), the analysis density is based on the characteristic curve shown in FIG. It can be uniquely converted into an exposure amount (exposure density). The table memory 209 stores a table of the characteristic curve of FIG. 7, and as shown in FIG. 8, analysis densities DC, DM, and
A pair of DY and exposure densities Dr, Dg, Db is stored.

The index conversion circuit 205 obtains the obtained exposure density D.
The following equations are calculated using r, Dg, and Db to obtain the exposure transmittances Tu, Tv, and Tw.

Tu = 10 ^-Dr , Tv = 10 ^-Dg , Tw = 10 ^-Db (14) The output of the exponential conversion circuit 205 is the matrix operation circuit 20.
6 is supplied. The matrix calculation circuit 206 uses the coefficients stored in the matrix coefficient memory 210 to perform the calculation of 3 rows and 3 columns shown in the equation (6) to calculate the tristimulus value (appearance) of the subject.
value) Colorimetric signals indicating R, G, B are obtained.

The numerical value of the matrix element Cij ^-1 stored in the matrix coefficient memory 210 can be easily determined from the relation of the equation (2) if the spectral sensitivity of the basic negative is completely equal to the color matching function. However, in reality, the spectral sensitivity and the color matching function do not match. So a certain color, for example Macb
The matrix element Cij ^-1 is obtained by the least squares method so that the tristimulus values obtained when converting the 24 colors of the eth Color Checker by the equation (6) and the actual tristimulus values match as much as possible,
It is stored in the matrix coefficient memory 210.

Next, referring to FIG. 6, the demodulation processing unit 102
A second example of the above, the configuration of the demodulation processing unit 102B will be described. As described above, since the characteristic curve when a scene is actually shot is often different from the characteristic curve obtained by the sensitometer due to the influence of camera flare, it is preferable to use the camera-through characteristic curve. However, a silver halide color light-sensitive material is usually vulnerable to heat and humidity, the characteristic curve tends to be distorted before and after photographing, and it is difficult to manage the processing liquid. Since an image also uses an organic dye, distortion is likely to occur, and even if a camera-through characteristic curve is obtained in advance, intended color reproduction cannot be realized when an actual scene is photographed.

Therefore, the camera is equipped with an exposure device in which the output is adjusted in consideration of the lens characteristics, and a specific portion outside the screen is exposed to all or part of the characteristic curve for each photographing, and the conversion table memory is converted from this image information. Input table information of characteristic values to 209a.

As shown in FIG. 6, this demodulation processing unit 1
02B is a conversion curve memory 209 of the above-described demodulation processing unit 102A to which a characteristic curve fetching unit for inputting table information of characteristic values is added. However, the same reference numerals are assigned to the components that perform the same processing as the demodulation processing unit 102A.

Characteristic value table information is input to the conversion table memory 209a from the characteristic curve acquisition unit 209b. The characteristic curve fetching unit 209b is composed of an A / D converter 211, an integration density conversion circuit 212, a matrix calculation circuit 213, an exposure density conversion circuit 214, a conversion table memory 217, and a matrix coefficient memory 218.
The A / D converter 211 receives the R, G, B analog video signals of part or all of the characteristic curves, which are read by the scanner 101 and exposed in advance on a specific portion outside the screen, and receive the R, G, B digital signals. The converted image signal is sent to the integrated density conversion circuit 212.

The conversion table memory 217 stores a conversion table as shown in FIG. Integral concentration converter 2
12 refers to the conversion table memory 217 to read R, G,
The B digital video signal is converted into the corresponding integrated density.
The matrix coefficient memory 218 stores a predetermined matrix coefficient, and the matrix calculation circuit 213 uses the matrix coefficient of the matrix coefficient memory 218 to convert the integrated density calculated by the integrated density conversion circuit 212 into an analytical density.

The exposure density conversion circuit 214 uses the analysis density from the matrix calculation circuit 213 to determine whether there is a deviation in the correspondence between the exposure density and the analysis density stored in the conversion table memory 209a, and there is a deviation in the conversion table. If so, adjust so that the correct correspondence is achieved. The other components are
Since it is the same as the demodulation processing unit 102A described above, description thereof will be omitted.

Next, the structure of the image processing unit 103 will be described with reference to FIG.

In FIG. 9, the colorimetric signal output from the demodulation processing unit 102 is supplied to the matrix calculation circuit 301. The matrix calculation circuit 301 includes a matrix coefficient memory 31.
By using the matrix coefficient Dij stored in No. 1, the matrix calculation of the equation (7) is performed, and the tristimulus values R _CR , G _CR , and B _CR for which the colors of the three phosphors of the color CRT are the primary stimuli are obtained. . Matrix coefficient D
As described above, ij is a coefficient when each primary color of the color CRT is represented by the sum of the three primary colors of the subject, and is obtained in advance by experiments using a color chart or the like.

The tristimulus values R _CR , G _CR , and B _CR output from the matrix calculation circuit 301 are the same as those in the image memory 302 and CR.
It is supplied to the T image memory 303. Image memory 302
Stores a relatively high resolution image data, and the CRT image memory 303 stores a part of the image data stored in the image memory 302 for CRT display, at a standard video speed of 30 frames per second. , Transfer the image data. The image data read out from the CRT image memory 303 includes the switch S3 and the digital-analog converter 30.
It is supplied to the color CRT 104 via 5 and displayed.

On the other hand, the data read from the CRT image memory 303 or the image memory 302 is supplied to the ACC (Aesthetic Color Correction) circuit 304 via the switch S1. The configuration of the ACC circuit 304 is a conventionally known configuration, for example, US Pat.
The configuration disclosed in 500919 can be adopted.

The tristimulus values R _CR , G _CR , and B _CR that have been subjected to aesthetic color correction processing by the ACC circuit 304 are supplied to the digital-analog conversion circuit 305 via the switches S2 and S3, and converted into analog signals. It is supplied to the color CRT 104 and displayed.

The image data subjected to the aesthetic color correction processing is supplied to the matrix calculation circuit 307 through the switch S2. The matrix operation circuit 307 performs the inverse operation of the matrix operation performed by the matrix operation circuit 301 based on the matrix coefficient stored in the matrix coefficient memory 312, and the tristimulus value R _CR that has been subjected to the aesthetic color correction processing, G _CR ,
_Reconvert B _CR into the tristimulus values R, G, B of the subject. The desk device 308 stores the tristimulus values R, G, B supplied from the matrix calculation circuit 307.

The switch S1 is normally connected to the CRT image memory 303, and is connected to the image memory 302 when the image data stored in the image memory 302 is transferred to the desk device 308. The switch S2 is connected to the switch S3 in a normal state, and is connected to the matrix calculation circuit 307 when transferring the image data stored in the image memory 302 to the desk device 308. The switch S3 is connected to the switch S2 in a normal state, and is connected to the CRT image memory 303 when aesthetic color correction is not performed.

Next, the configuration of the output circuit 105 will be described with reference to FIG.

In FIG. 10, the tristimulus values R, G, B of the subject output by the image processing unit 103, that is, the output of the matrix operation circuit 307 or the output of the matrix operation circuit 307 stored in the desk device 308 are Logarithmic circuit 4
01 is supplied. The logarithmic circuit 401 is the reference value memory 40.
Using the tristimulus values R0, G0, B0 of the white point stored in No. 2, the calculation shown in the equation (10) is performed, and the color material signal (c , M, y) is obtained and supplied to the matrix operation circuit 403.

As described above, the color material of the actual color paper is not the block dye. Therefore, the matrix calculation circuit 403 uses the coefficient fij stored in the matrix coefficient memory 404.
^The equation (11) is calculated by using ⁻¹ to obtain the actual color material densities c *, m *, and y *. The coefficient fij (i is not equal to j) indicates the ratio of the sub-absorption concentration to the main concentration, and the coefficient fij (i = j) indicates the main concentration. These coefficients are obtained in advance by experiments, and vice versa. A matrix is obtained and its coefficient fij ^-1 is stored in the matrix coefficient memory 404. Color material density c *, m output from the matrix calculation circuit 403
* And y * are supplied to the calibration circuit 405.

In general, the output of the laser printer fluctuates due to various factors (for example, room temperature, history after turning on the laser). Further, even when the color paper is exposed to a certain amount of light and developed, the color paper changes due to various changes in the composition of the developing solution and the like and is not constant. Therefore, in order to obtain the desired density correctly, the test pattern is exposed and developed, and the output of this test pattern is measured with a densitometer,
The laser output of the laser printer must be adjusted to obtain the correct output. Therefore, the calibration circuit 4
05 is the concentration c *, m based on the measurement data of the densitometer
Properly calibrate * and y * and supply them to the color printer 106.

In response to the output of the calibration circuit 405, the color printer 106 forms an image faithfully reproducing the color of the subject on the color paper.

(Operation) A series of operations from acquisition of an image by the image processing system having the above-described configuration to display on the color CRT 104 and hard copy by the color printer 106 are summarized as flowcharts shown in FIGS. 11 and 12. . The operation will be described below with reference to FIGS. 11 and 12. However, the demodulation processing unit 102 applies the demodulation processing unit 102A shown in FIG.

First, the subject is photographed and developed to fix the subject image on the basic negative (step T1). This operation is performed outside the image processing system.

Next, the image fixed to the basic negative is converted into R, G, B analog video signals in units of pixels using the scanner 101 (step T2). The output of the scanner 101 is converted by the A / D converter 201 into digital image signals of RGB (step T3).

The density converter 202 has a table memory 207.
R by referring to the conversion table (FIG. 7) stored in
G and B digital video signals corresponding to corresponding integrated densities DR and D
Convert to G and DB (step T4). The maritrix calculation circuit 203 uses the matrix coefficient stored in the matrix coefficient memory 208 to perform a matrix calculation of 3 rows and 3 columns with an integrated density D.
It is applied to R, DG, and DB to obtain analytical concentrations DC, DM, and DY (step T5).

The exposure density conversion circuit 204 refers to the conversion table (FIG. 8) stored in the table memory 209,
Analysis densities DC, DM, DY are exposure densities Dr, Dg, Db
(Step T6).

The exponent calculation circuit 205 determines the exposure densities Dr, D
Exposure transmittance Tu (= 10 ^−Dr ), Tv using g and Db
(= 10 ^-Dg ) and Tw (= 10 ^-Db ) are obtained (step T7).

The matrix calculation circuit 206 uses the matrix coefficient stored in the matrix coefficient memory 210 to determine the exposure transmittance T.
The matrix calculation of 3 rows and 3 columns shown in the equation (6) is performed on u, Tv, and Tw, and the tristimulus value (appearance value) of the subject is obtained.
R, G, B are obtained (step T8).

The tristimulus values R, G, B are supplied to the matrix calculation circuit 301 (FIG. 9), and the tristimulus values R _CR , G _CR , B _CR for the primary stimuli of the three phosphors of the color CRT are used. (Step T9).

When the aesthetic color correction processing is not performed, the tristimulus values R _CR , G _CR and B _CR are once stored in the CRT image memory 303 and then supplied to the DAC 305 via the switch S3 to be converted into digital data. Converted (step T1
0) is supplied to the color CRT 104 and displayed (step T11). As a result, the color CRT 104 displays a subject image that faithfully reproduces the color of the subject.

On the other hand, when performing aesthetic processing, one of the image memories 302 and 303 is selected by the switch S1,
The ACC circuit 3 is added to the data read from the selected memory.
An arbitrary color correction process is performed at 04 (step T12). If necessary, the color-corrected data is supplied to the color CRT 104 via the DAC 305, and the color-corrected subject image is displayed (step T13).

If necessary, the color-corrected image data is supplied to the matrix calculation circuit 307, reconverted into the three primary colors R, G, B of the subject, and then stored in the desk device 308.

Further, the image data after color correction is output from the output circuit 105 for the three primary colors R, G and B of the subject supplied directly from the matrix calculation circuit 307 or from the desk device 308.
Is supplied to the color paper and is converted into the color material signal of the color paper (T
14) Further, appropriate calibration processing is performed on the color material signal (T15). The color printer 106 forms an image faithfully reproducing the color (hue) of the subject on the color paper based on the color material signal (T16).

As described above, according to this embodiment,
An image that faithfully reproduces the color (hue) of the subject is displayed as color C
It can be displayed on the RT 104 and can be formed on color paper by the color printer 106.

In the operation described above, the demodulation processing unit 102A of the first example is used as the demodulation processing unit 102. However, when the demodulation processing unit 102B is used, the exposure density is calculated (T
It is sufficient that the table of the conversion table memory 209a is adjusted by the characteristic curve reading unit 209b before 6) is executed. Thus, when the demodulation processing unit 102B is applied, an image in which the color of the subject is faithfully reproduced can be reproduced even when the characteristic curve of the photosensitive material is distorted due to various causes.

The present invention is not limited to the above embodiment.

For example, in the above-described embodiment, the basic negative is formed from three photosensitive layers, and each photosensitive layer develops any one of C, M, and Y depending on the exposure amount.
It is also possible to use a film composed of 5 layers, so that each photosensitive layer develops two or more colors. Further, the spectral sensitivity of each photosensitive layer is not limited to that shown in FIG. 3, and a film exhibiting another spectral sensitivity may be used. However, it is desirable that the spectral sensitivity be as close as possible to the color matching function, which is the color sensitivity characteristic of human being, shown in FIG. 1, and in particular, the q factor thereof is 0.9 or more.

Further, in the configuration of FIG. 5, each operation is performed by a plurality of circuit blocks for converting the output of the scanner 101 into the tristimulus values R, G, B of the subject. It is also possible to use a calculation processor to perform all the calculations by software.

Further, in the configuration of FIG. 5, the exposure density conversion circuit 204 converts the analysis density into the exposure density based on the table stored in the exposure density conversion table 209. From the characteristic curve shown in FIG. It is also possible to derive a predetermined relational expression and obtain the exposure density from this relational expression. Also,
In FIG. 10, the logarithmic circuit 401 performs the calculation of the equation (10), but a lookup table showing the relationship between the output of the image processing unit 103 and the block dye densities c, m, and y is provided.
The output of the image processing unit 103 may be converted into the block dye densities c, m, and y by referring to this table.

Removing the switch S2 from the configuration of FIG.
The output terminal of the ACC circuit 304, the DAC 305, and the matrix calculation circuit 307 may be constantly connected so that image data after aesthetic color correction is always supplied to these circuits. Further, the ACC circuit 304 may be turned on / off so that image data not subjected to aesthetic color correction can be supplied to the matrix calculation circuit 307 and the DAC 305.

In the above embodiment, the matrix operation circuit 30
Reference numeral 7 indicates the tristimulus values R, G, and
It was converted back to B, but converted to other data and the desk device 3
08 may be stored. For example, it may be converted into an XYZ tristimulus value that uses the X, Y, and Z primary colors as the primary stimulus recommended by the International Commission on Illumination, and a colorimetric value that is modified based on this. These values are not unique to the actual device or system, but are universal values, and if these values are stored in the desk device 308, they are effective for exchanging signals between arbitrary media. is there. The color printer 106 is not limited to the laser printer, but may be a thermal transfer printer,
An electrophotographic printer, an inkjet printer or the like may be used.

When the demodulation processing unit 102B is applied, the reference image (characteristic curve) is recorded in advance in a specific area outside the photographing screen of the color film almost at the same time as photographing. The reference image may be exposed immediately before. Further, by such processing, it is possible to recognize the stability of the characteristic curve of the light-sensitive material, such as change and fluctuation.

[0092]

As described above, according to the present invention,
Since the negative film is mainly in charge of the imaging function and the color correction function is performed by digital image processing, the film structure is simplified and an image in which the color of the subject is faithfully reproduced can be reproduced. Also, even if the photosensitive material has a distortion in the characteristic curve due to various causes, the intended image can be reproduced,
The reliability of the system also improves.

[Brief description of drawings]

FIG. 1 is a graph showing human color sensitivity.

FIG. 2 is a graph showing absorption characteristics of a block dye and an actual dye.

FIG. 3 is a graph showing spectral sensitivity characteristics of a color negative film (basic negative) according to an example of the present invention.

FIG. 4 is a block diagram showing an overall configuration of an image processing system according to an embodiment of the present invention.

5 is a block diagram showing a configuration of a first example of a demodulation processing unit shown in FIG.

6 is a block diagram showing the configuration of a second example of the demodulation processing unit shown in FIG.

7 is a diagram showing an example of a conversion table stored in a conversion table memory 207 of FIG. 5 and a conversion table memory 217 of FIG.

FIG. 8 is a diagram showing a characteristic curve showing a relationship between analysis density and exposure density.

9 is a block diagram showing a configuration of an image processing unit shown in FIG.

10 is a block diagram showing a configuration of an output circuit shown in FIG.

FIG. 11 is a flow cheat showing the first half of the schematic operation of the entire system.

FIG. 12 is a flow cheat showing the latter half of the schematic operation of the entire system.

[Explanation of symbols]

101 ... Scanner, 102 ... Demodulation processing section, 103 ... Image processing section, 104 ... Color CRT, 105 ... Output circuit, 1
06 ... Color printer, 201, 211 ... Analog-digital converter, 202, 212 ... Integral density conversion circuit, 20
3, 206, 213, 301, 307, 403 ... Matrix operation circuit, 204, 214 ... Exposure density conversion circuit, 2
05 ... Exponential operation circuit, 207, 209, 217, 209
a ... conversion table memory, 208, 210, 218, 3
11, 312, 404 ... Matrix coefficient memory, 209b ... Characteristic curve capturing unit, 302 ... Image memory, 303 ... CR
Image memory for T, 304 ... Aesthetic color correction circuit, 305 ...
Digital-analog conversion circuit, 308 ... Desk device, 40
1 ... Logarithmic circuit, 402 ... Reference value memory, 405 ... Calibration circuit.

Claims (11)

[Claims] 1. An input conversion means for reading an image of a subject fixed on a film and converting it into a corresponding signal, and a colorimetric measurement connected to the input conversion means and showing colorimetric information of the subject in response to the signal. An image processing system comprising: a demodulation unit that demodulates a signal; and an output unit that is connected to the demodulation unit and that outputs an image having substantially the same hue as the subject based on the colorimetric signal. . 2. The demodulating means converts the signal from the input converting means into a signal indicating the exposure transmittance of the object, and a predetermined matrix of 3 rows and 3 columns for the signal indicating the exposure transmittance. The matrix calculation means for demodulating the color measurement signal indicating the color measurement information of the subject.
The image processing system described. 3. The demodulating means analyzes the integrated density by applying means for converting an output signal of the input converting means to an integrated density of a subject and a matrix operation of predetermined 3 rows and 3 columns on the integrated density. A means for converting the density, an exposure density converting means for converting the analysis density to an exposure density based on a characteristic curve of the film, and a means for obtaining an exposure transmittance by performing a predetermined index calculation using the exposure density. 2. The image processing system according to claim 1, further comprising means for performing a matrix operation of predetermined 3 rows and 3 columns on the exposure transmittance to reproduce color measurement information of a subject. 4. The exposure density conversion means of the demodulation means,
Storage means for storing correspondence information between analysis density and exposure density based on the characteristic curve of the film in advance, and reference information read from the characteristic curve information of the film recorded outside the photographing screen of the film in advance, and this reference Adjusting means for adjusting the correspondence between the analysis density and the exposure density in the storage means based on the information, and the correspondence information in the storage means are referred to, and the analysis density obtained by the matrix calculation is converted into the exposure density. The image processing system according to claim 3, further comprising: 5. The display device, in response to the colorimetric signal, displays an image having a color substantially the same as the color of the subject, and the color of the subject on a predetermined output medium. 5. The image processing system according to claim 1, further comprising at least one of printers that form images having the same color. 6. The output means converts the colorimetric signal from the demodulation means into a colorimetric signal based on the three primary colors used for image formation by the output means, and the converted colorimetric signal. 5. The image processing system according to claim 1, further comprising: a storage unit and a unit that outputs an image in accordance with the converted colorimetric signal read from the storage unit. 7. The output means performs a logarithmic conversion of the colorimetric signal, and performs a matrix operation of 3 rows and 3 columns on the logarithmically converted colorimetric signal to obtain a density of a color material forming an output image. 5. The image processing system according to claim 1, further comprising: a unit that obtains a color material signal that indicates. 8. The output means comprises a table showing the relationship between the colorimetric signal and the color material signal, and means for converting the colorimetric signal into the color material signal with reference to the table. The image processing system according to any one of claims 1 to 4, which is characterized. 9. The image processing system according to claim 1, wherein the output means further comprises aesthetic color correction means for aesthetically modifying the colorimetric signal. 10. A colorimetric quality coefficient of the spectral sensitivity of the photosensitive layer is 0.9 or more, including three photosensitive layers that develop one color corresponding to cyan, magenta, and yellow according to the exposure amount. The image processing system film according to claim 1, wherein the film does not include a coupler and a DIR coupler. 11. Cyan, magenta, and yellow are colored in accordance with the exposure amount, the spectral sensitivities are all positive values, and the quality coefficient indicating the degree of coincidence between the spectral sensitivity and human color sensitivity is 0.9 or more. Fixing a subject image on a film, converting the subject image on the film into corresponding image data, demodulating subject color information from the image data, based on the color information And a step of outputting an image having substantially the same color as the subject, the image processing method.