JPS63133141A - Automatic photographic printer provided with parameter determining device for simulator - Google Patents

Abstract

PURPOSE:To perform simulation of high precision by calculating such values of parameters that the sum of distances on a chromaticity diagram between the chromaticity of each reference color of the picture of a reference print and that of the picture of a simulator corresponding to each reference color is minimum and allowing the simulator picture and the print picture to coincide with each other. CONSTITUTION:Colorimeters 44 and 42 are provided to measure chromaticities of the picture displayed by a simulator 34 and a reference print 27 which is obtained by printing and developing the image of a reference color negative, where plural different reference colors are photographed, by an automatic photographic printer with the quantity of light fixed, and parameter operating means 46, 48, and 50-60 are provided to operate such values of parameters that the sum of distance on the chromaticity diagram between the chromaticity of each reference color of the picture of the reference print 27 and that of the picture of the simulator 34 corresponding to each reference color is minimum. Parameters for the minimum sum of distances are used to convert picture information, thereby allowing the print picture and the simulator picture to most coincide with each other with respect to hue and chroma.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic photo printing apparatus equipped with a simulator parameter determination device, and more particularly, to an automatic photo printing apparatus that is equipped with a simulator parameter determination device, and particularly for printing an image identical to a finished print printed by a color automatic photo printing apparatus. C
The present invention relates to a device for determining simulation parameters to be displayed on RT.

[Conventional technology]

Conventionally, the integrated transmission density (LATD) of the entire image of a color negative film is measured, density correction is performed, and slope control is performed to ensure that the density and color balance of all finished prints are the same as that of the negative (exposure amplifier, appropriate exposure, An automatic color photographic printing apparatus (printer) is known that prints and develops images to be identical regardless of overexposure. This automatic photographic printing apparatus is constructed by sequentially arranging an optical system including a light source, a light control filter, a mirror box, a negative carrier, and a black shutter. Printing is performed by placing a color negative film on a negative carrier, turning on a light source, opening a black shutter, and forming an image of the color negative film on photographic paper. The printed photographic paper is developed in a developing process to automatically complete the print.

This automatic photo printing device separates the light beam transmitted through the negative film into red light (R), green light (G), and blue light (B) using a light-receiving element.
The burn density is controlled using ATD and the slope is 3.
I use slope control to control the color balance so that the primary colors match. Therefore, with this automatic photoprinting apparatus, all normally finished prints have the same density and color balance.

However, even if the main subject of a color negative film has an appropriate density, if the background is dark or light,
Since the exposure amount is controlled under the influence of this background density, density fettling occurs.

Additionally, if the color balance of the main subject differs from the color balance of the background, for example if the main subject color and the background color are complementary colors, color feria will occur, and density correction or slope control may be necessary. The quality of the print may also deteriorate. In this way, if the finished state of the print deteriorates, it becomes necessary to carry out printing and development again.

For this reason, in the past, as shown in Japanese Unexamined Patent Publication No. 53-46731, a color video signal has been developed to obtain the desired density and color balance while imaging a negative film with a TV camera and displaying the image on a TV screen. A so-called photo verification device is used in which the color video signal is adjusted and printed in an automatic photo printing device using this color video signal. In addition, as shown in Japanese Patent Publication No. 42-25220,
It is possible to reduce the frequency of reprinting and development by displaying the image of the negative film printed on photographic paper on the TV screen and linking the automatic exposure device with the brightness and contrast adjustment resistors of the TV. It is being done.

[Problem that the invention seeks to solve]

However, in the method using a verification device, the light source of the verification device and the light source of the automatic photoprinting device are separate, so even if printing and development is performed using the automatic photoprinting device using the information obtained by the verification device, the light source is There is a problem in that the same image as the image displayed on the TV screen cannot be printed due to changes or the like.

Furthermore, when an automatic exposure device is linked with the TV's brightness and contrast adjustment resistors, an appropriate image is simply displayed on the TV screen even though the coloring characteristics of the TV and the coloring characteristics of the print are different. However, the problem is that the same image that is printed is not displayed on the TV screen.

Therefore, in order to solve the above-mentioned problems, the present inventor has previously proposed a simulator that can display the same image as the finished print. SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic photoprinting device equipped with a device for determining parameters of the simulator such that many colors of the image displayed on the simulator match many colors of the image printed on the print. shall be.

[Means for solving problems]

In order to achieve the above object, the present invention captures an image of a color negative film illuminated by a light source system whose light is adjusted by the automatic exposure control function of an automatic photographic printer, and acquires image information of the negative image recorded on the color negative film. In an automatic photoprinting apparatus, the automatic photoprinting apparatus includes a device for determining parameters of a simulator that converts the image information using parameters to display an image identical to a positive image of a print obtained by the automatic photoprinting apparatus. a chromaticity meter for measuring the chromaticity between a reference print obtained by printing and developing images of reference color negatives photographed with different reference colors by the automatic photoprinting device under a constant light source condition and an image displayed by the simulator; A parameter that calculates the value of a parameter that minimizes the sum of the distances on a chromaticity diagram between the chromaticity of each reference color of the image of the reference print and the chromaticity of each reference color of the simulator image corresponding to each reference color. It is characterized in that it is provided with a calculation means.

Here, the parameter calculation means weights the specific reference color so that the sum of chromaticity distances on the chromaticity diagram of the specific reference color is equal to the chromaticity distance on the chromaticity diagram of other than the specific reference color. It is preferable that the distance be smaller than the sum of the distances.

[Effect]

The simulator of the present invention obtains image information of the negative image by capturing a negative image recorded on a color negative film illuminated with a light source system whose light is adjusted by the automatic exposure control function of an automatic photoprinting device, and calculates the image information of the negative image. The image is converted using parameters to display an image identical to the positive image of the print obtained from the color negative film.

The chromaticity meter measures the chromaticity of the CRT used in the simulator and the chromaticity of the reference print obtained by printing and developing a reference color negative image of multiple different reference colors using an automatic photo printing machine. The chromaticity of each monochromatic emission of RlG and B is measured. The parameter calculation means calculates the value of the parameter that minimizes the sum of the distances between each color of the reference pudding 1 to the corresponding color on the CRT. Then, the image information of the negative image is converted using the parameters calculated as described above and displayed on the simulator.

Here, the chromaticity diagram shows x and y related to hue and saturation among the chromaticity coordinates X, y'-, and Z as orthogonal coordinates, so
By converting image information using a parameter that minimizes the sum of distances, it is possible to best match the hue and saturation between the print image and the simulator image.

Furthermore, if the parameters are determined so that the sum of the distances is the minimum for the brightness expressed by coordinates perpendicular to the orthogonal coordinates representing the chromaticity diagram, the brightness of the simulator image and the brightness of the printed image can be can be matched even more optimally.

As a result, the parameters are determined so that all the colors in the simulator image best match all the colors in the print image, so for any negative image, the print image and the simulator image will be the same. can be made the closest one. In order to determine the parameters so that the sum of the above-mentioned distances is minimized, it is determined by performing the least squares method or regression that minimizes the sum of the squares of the above-mentioned differences, that is, by performing optimization. I can do it.

In addition, for specific reference colors that often appear on general users' color negative films, such as skin tones and grays, weighting is done by increasing the number of samples of reference colors that are close to the specific reference color. It is preferable that the sum of distances on the chromaticity diagram be particularly small.

〔Effect of the invention〕

As explained above, according to the present invention, photographic paper and CR
It is a chromaticity meter that measures the chromaticity point of T, and is equipped with a device that measures the reference color of the print image and the reference color of the image displayed on the CRT of the simulator, and calculates this to determine the parameters. The effect is that even if there are variations in paper development conditions or variations in the coloring characteristics of the CRT's phosphor, it is possible to perform a highly accurate simulation in which the image displayed on the CRT matches the finished image of the print. can get.

〔Example〕

A simulator to which the present invention is applicable will be described in detail below with reference to the drawings. FIG. 1 shows a simulator to which the present invention is applicable.

As shown in FIG. 1, on the back side of a light source 10 made up of a halogen lamp, there is a reflecting mirror 1 made up of a cold mirror.
2 is placed. A voltage of about 90% of the rated voltage is supplied to the light source 10 from a power supply device (not shown) in order to prolong the life of the light source 10 and obtain a predetermined color temperature of 0 degrees Celsius. On the light irradiation side of the light source 10, Y (yellow) and M ( A light control filter 14 consisting of three complementary color filters of magenta) and C (cyan) and a mirror box 16 equipped with a scattering plate are arranged in this order, and the light rays emitted from the light source 10 are transmitted to the light control filter 14.
After the color balance and light amount are adjusted in step 4, the light is converted into uniform diffused light in a mirror box 16, and the diffused light is irradiated onto a color negative film 18 held on a negative carrier. To adjust the above light source voltage, set each complementary color filter of the dimmer filter to the mechanical center, measure the light amount with a luminometer, and adjust it to a constant light amount (standard exposure time). Adjust so that 90% of the voltage is supplied. An optical system 20 and a black shutter 2 are provided on the transmitted light beam exit side of the color negative film 18.
2 are arranged in this order, and the black shutter 22 is opened to form an image on the photographic paper 24 using the light that has passed through the color negative film, exposing the photographic paper. The exposed photographic paper 24 is processed in a development process 25 to form a print 27.

A drive circuit 26 is connected to the light control filter 14, and the drive circuit 26 moves each of the complementary color filters in a direction perpendicular to the optical axis, thereby making it possible to adjust the color balance and light amount. Further, a drive circuit 29 is connected to the black shutter 22 .

Near the optical system 20 side of the color negative film 18, R
Equipped with three filters that transmit (red) light, G (green) light, and B (blue) light, respectively, and outputs R, G, and B signals.
Camera 30 composed of a board camera and 3 of R, G, and B
An image information detection device 32 equipped with a two-dimensional image sensor for detecting image density information of primary colors is arranged.

This two-dimensional image sensor is a CCD (charge coupled device)
It consists of Note that the camera 30 may be configured with a single CCD camera.

Here, in a normal TV system, the γ of the TV is approximately 2.2, so a γ correction circuit with γ = 0.45 is installed in the TV camera so that the overall value is γ-1. , since the γ of photographic paper is approximately r=2.0, in this embodiment, a γ correction circuit is not provided in the camera 30, and γ in the simulator is set to approximately 1, and together with the γ value of the negative, the overall γ is
#1.0.

The camera 30 is connected to a simulator 34 via a gain control circuit 33, and the image information detection device 32 is connected to a slope control circuit 62 via a δ and γ correction circuit 38 and a printing system density calculation circuit 40. has been done. The printing system density calculation circuit 40 and the slope control circuit 62 perform the color balance and density correction described above. Further, a chromaticity meter 42 is arranged to face the screen of the CRT 345 constituting the simulator 34, and a chromaticity meter 44 is arranged to face the screen of the print 27. The color changing needles 42 and 44 are connected to an I10 boat 46 that constitutes a computer. The computer acting as distance calculation means and parameter calculation means is the above ■/○ boat 46, CPU
48, Read Only Memory (ROM) 50, Random Access Memory (RAM>52, Digital-Analog (
D/A) converter 54, analog-digital (A/D) converters 56, 58, and buses 60 such as data buses and control buses that connect these.
It is connected to a gain control circuit 33 , a simulator 34 , a δ and γ correction circuit 38 , a slope control circuit 62 connected to a printing system density calculation circuit 40 , a drive circuit 26 , and a drive circuit 29 .

The gain control circuit 33 is composed of an amplifier 331, an operational amplifier 332, a flip-flop 333, and resistors 334 to 336, as shown in FIG. A reference voltage (0.7V corresponding to the white level) is input. In order to adjust the gain of the camera 30 using the gain control circuit 33, a reference negative (so-called plain negative) obtained by developing an unimaged film is imaged by the camera 30, and the camera outputs each of the three primary colors R, G, and B. On the other hand, this is done by outputting an analog signal from the D/A converter 54 and stopping the gain adjustment when the signal is output from the flip-flop 333. As a result, the camera's own level can be adjusted when the blank is negative (when the transmitted light of the negative is maximum), so the brightness standard can be easily and accurately determined.

In addition, the iris position and color balance position of the camera after the gain is adjusted as described above are stored as digital values, and the negative size (the amount of light changes because the magnification is different)
If you channelize each time, you can change the channel by simply switching the channel each time you change the negative size.

By doing this, even if the negative size changes, the iris position and color balance position of the camera can be changed simply by changing the channel. In the above case, if the light source deviates from the standard state, it will be necessary to electrically correct the deviation, so it is preferable to adjust the light source state so that a standard gray negative is finished as a standard gray print.

As shown in FIG. 3, the δ and γ correction circuit 38 includes a signal processing circuit 60 that converts the R signal output from the image information detection device 32 into a density signal and performs δ and γ correction; It is comprised of a signal processing circuit 62 that converts the B signal into a signal and performs δ and γ correction, and a signal processing circuit 64 that converts the B signal into a density signal and performs δ and γ correction. Since these signal processing circuits 60, 62, and 64 have the same configuration, only the signal processing circuit 60 will be described. The signal processing circuit 60 includes an offset correction circuit 601, a logarithmic conversion circuit 602 for converting into a density signal, a δ correction circuit 603, and a γ correction circuit 604. The offset correction circuit 601 includes an operational amplifier OP3, resistors R6 and R7, and a variable power supply B1. The δ correction circuit 603 includes an operational amplifier OP4,
It is composed of resistors R6 and R7 and a variable power supply B2.

Then, the R, G, and B signals are corrected by δ and γ and output.

1) The above simulator 34 uses a logarithmic converter 341 connected to the output terminal of the gain control circuit 33 to correct the difference between the density (integral density) seen from the spectral sensitivity of the camera and the density seen from the spectral sensitivity of the photographic paper. A 3×3 matrix (cubic square matrix) circuit 342, an N/P inversion circuit 343 that inverts the negative/positive (N/P) and converts it into the analytical density of photographic paper, and converts the analytical density of the photographic paper into the fluorescent light of the CRT. It is constructed by sequentially connecting in series a luminance signal conversion circuit 344 that converts the luminance of each color of the body, and a CRT 345 that causes a phosphor to develop color according to the output of the luminance signal conversion circuit 344 and displays an image captured by the camera 30. There is.

Here, the value obtained by logarithmically converting each of the B, G, and R signals output from the camera 30 by the logarithmic conversion circuit 341, that is, the color negative 3 matrix A- of the received light spectral characteristics is calculated based on the spectral sensitivity of the camera.
' (However, -1 indicates an inverse matrix) to convert to negative analytical density as shown in the following equation.

Further, when the integral density of a color negative film image in terms of the spectral sensitivity of photographic paper is converted to an analytical density of a negative using 3×37 Trix B-1, where BP, 'Gr, and RP are expressed, the following equation is obtained.

Negative analytical density (BTv) in equations (1) and (2) above
, Grv, Rrv) and (By', Gp, Rp)
Since it is proportional to , it can be expressed as the following (3) 2 using a diagonal matrix α whose diagonal components are proportional constants.

Therefore, using equations (1) to (3) above, (B+', Gr
, R, ) and (BTv, GTv, RTv), the following equation (4) is obtained, which allows us to calculate the relationship between the integral density based on the spectral sensitivity of the TV and the integrated density based on the spectral sensitivity of the photographic paper. Differences are corrected.

In the 3×3 matrix circuit 342, parameters expressed by matrix components shown below are set.

The N/P inversion circuit 343 is a circuit that converts T into -γ, and converts the output of the 3×3 matrix circuit 342 according to the following straight line and outputs the converted signal.

y-y+ = a (x-x,)...-(6) However,
XI,)'I is the coordinate value of the point that is not inverted in N/P (hereinafter referred to as the pivot point), x, y are the coordinate values when the density area is expressed in xy coordinates, and a is the gradation level at the time of N/P inversion. negative values are usually chosen.

As the pivot point, a point where the density should not change even if the N/P is reversed is selected. In cameras and CRTs, the range from black level to white level is displayed at 0 to 0.7 V, so if you take the logarithm of the image signal, the black level becomes 1, making it impossible to accurately invert the black level to the white level. . Therefore, in N/P inversion, camera output vI
, l is preferably 23% (0.63 in density excluding the negative base) of the white level as a pivot point for N/P inversion.

Figure 4 shows the camera output Vi when the camera output vI, is inverted N/P with 23% of the white level of l as the pivot point.
n and N/P inversion circuit 343 output V. The relationship with ut is shown. Since the white level of the camera is 0.7 volts, 23% of the white level is 0.161 volts. here,
3×3 matrix circuit 342 output, )' = 3.2518 + II og V In
++ Expressed as (7), the coordinates corresponding to 23% of the white level are (0,161,2,47). Therefore, (2
, 47, 2, 47) -2,47= a (x-2,47)...(8
), the curve expressed by the above equation (7) is converted to obtain the curve shown in FIG. 4, which is N/P inverted. As understood from FIG. 4, the value of 23% of the white level of the camera output remains unchanged even after the N/P inversion.

Further, in order to perform N/P inversion, the N/P inversion circuit may be configured with the circuit shown in FIG. 5, and the N/P inversion may be performed by finding a pivot point as described below. The circuit shown in Fig. 5 is constructed by moving the operational amplifiers ○P1 and O20, the variable resistor R1 that sets the operational amplifier reference voltages V and ■y (corresponding to the pivot point), and the contacts of the variable resistor R1. It is equipped with an actuation mechanism AC that changes the reference voltage. A signal is input to the inverting input terminal of the operational amplifier OPI via a resistor R2, and a variable resistor R3 for adjusting the gain is connected between the inverting input terminal and the output terminal of the operational amplifier OP1. The output terminal of the operational amplifier OPI is connected to the inverting input terminal of the operational amplifier OP2 via a resistor R4. A resistor R5 is connected between the inverting input terminal and the output terminal of the operational amplifier OP2. Variable resistor R1
One end is grounded, the other end is grounded via power supply B, and the contacts of variable resistor R1 are connected to the non-inverting input terminals of operational amplifiers OPI and O20, respectively.

A method for determining the pivot point using the above circuit will be explained. First, a color negative film that develops a standard gray color is held between negative carriers and imaged by a camera, and after N/P inversion is performed using the circuit shown in FIG. 5, the image is displayed on a CRT screen. next,
A standard gray signal (which can be created electrically by setting the white level of the CRT to 23%) is displayed on the CRT screen in close proximity to the above-mentioned negative image. Then, by operating the keyboard, the resistance value of the variable resistor R1 is continuously changed to change the reference voltages VX, V, and a negative image colored in standard gray is electrically created as an image using a standard gray signal. Match.

This determines the pivot point.

By using the above circuit, it is possible to set the gray level according to the sense of the measurer, and since the gray level can be set according to the sense of the measurer, it is possible to match the finished state of the print. The gray level can be set, which allows highly accurate simulations to be performed, including conditions such as development conditions (fatigue of the developer, temperature changes in the developer, etc.).

Correction of Color Spectral Characteristics Since a CRT displays an image using a light emitter, the brightness of the CRT is proportional to the voltage. However, since printing uses an absorber (dye), the amount of dye and brightness are not proportional, but the amount of dye and the logarithm of brightness are proportional, and if the amount of dye is changed, the chromaticity point changes. do. That is, the dyes in the print are unstable primary colors (C1Y, M) whose chromaticity point changes depending on the amount of dye.

Therefore, the luminance signal conversion circuit 344 has N
The /P inversion circuit 343 output is converted into an analytical luminance signal T and output to the CRT 345.

T=F (j! o g−' (f (D)) )・
(9) where f is a function that converts the output into an integrated density, and F is a function that converts the integrated transmittance (log-' (D)) into an analytical luminance signal.

A 3×3 matrix is generally used as the coefficients (parameters) of the functions F and f.

Then, the CRT is controlled by the luminance signal obtained by the luminance signal conversion circuit 344 as described above, and the CRT is
An image having coloring characteristics matching those of the print is displayed on T.

Determination of Parameters The parameters set in the 3×3 matrix circuit 342 and the luminance signal conversion circuit 344 are determined as follows.

That is, each component of the matrix in equation (5) above is obtained by imaging a reference negative (hereinafter referred to as a Maches negative) that is an image of a chart or the like made of a plurality of different reference colors with a camera, and performing logarithmic transformation of each block of the imaged Maches negative. In addition to measuring the spectral density of each block of the Maches negative, the printing density of the print is calculated from the measured spectral density and the spectral sensitivity of the photographic paper, and this is used as the target value. The size is determined by the CPU 4B performing optimization using the method of least squares or the like so that the input matches the target value. Note that when determining the components of the 3x3 matrix, weighting is performed by increasing the number of samples for specific colors (e.g., skin tone and gray) so that these inputs specifically match the target values. is preferable.

On the other hand, if the tristimulus values of photographic paper are (X, Y, Z) and the integral transmittance is (TR, Tc, TB), then there is the following function.

The electric signal (target value) given to RT is (TR, Tc, TB
), we have the following relationship.

Therefore, tristimulus values (X, Y, Z) and tristimulus values (X', Y
Assuming that o, Z') are equal, the above equations (10) and (1) are used. Since (12) is equal to the tristimulus value of the photographic paper from equation (10), the final print 27 is calculated by the chromaticity meter 44. It is determined by measuring the chromaticity point.

In addition, the components of the inverse matrix of equation (12) are obtained by measuring the chromaticity points of the tristimulus values of the CRT with the chromaticity meter 42,
In the above formula (1), set 'rt, = 'r - 0 and set TR to a predetermined voltage to find XR, Ym, and ZR,
Similarly, T * = T m = O and T6
Determine XG, Yc SZc by setting the voltage to the specified voltage, and calculate TL
- Set TG-0 and set TB to the specified voltage,
It can be determined by finding Yll and zH. As a result, the electrical signal to be applied to the CRT, that is, the target value, can be determined from equation (12).

Then, using the components of the 3×3 matrix circuit 342 determined as described above and multiplying them by −T, N
/P and the output of the circuit 343 is D (luminance signal conversion circuit 34
4 input) and the target value (Tel, T:, , T
Since L ) is determined as above, the above (9)
The parameters of the functions F and f can be determined by performing optimization such as the least squares method or regression based on the equations. Note that when determining this parameter, it is preferable to weight specific colors (for example, skin color, gray, etc.) so that these inputs particularly match target values.

As a result, the sum of the chromaticity distances on the chromaticity diagram for each color between the reference color of the reference print image and the reference color of the simulator image is minimized, and the hue and saturation of the CRT image and the print image are the difference is minimized. If the above parameters are determined periodically or for each type of photographic paper and stored in a RAM, etc., fluctuations in development characteristics due to developer fatigue or changes in developer temperature can be avoided. Even if the characteristics of the photographic paper change, it is possible to perform a highly accurate simulation that matches the CRT image with the print image.

The difference between the above chromaticity points is expressed quantitatively by the geometric distance between the point corresponding to each reference color of the print and the point corresponding to each reference color of the CRT on the chromaticity diagram, and the above calculation is performed. will be held.

Note that although an example in which the chromaticity distance is minimized has been described above, parameters may also be determined so that the brightness expressed by coordinates orthogonal to the chromaticity diagram is also minimized. Moreover, although an example in which two chromaticity meters are used has been described above, one chromaticity meter may be switched and used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the gain control circuit shown in FIG. 1, and FIG.
A circuit diagram showing an example of the δ and γ correction circuit shown in Fig. 4.
A diagram for explaining P inversion, and FIG. 5 is another circuit diagram for performing N/P inversion. 14... 8 round light film, 27... Print, 34... Simulator.

Claims (3)

[Claims] (1) Image information of the negative image recorded on the color negative film is obtained by capturing an image of a color negative film illuminated by a light source system whose light is adjusted by the automatic exposure control function of an automatic photo printing device, and the image information is converted into parameters. In an automatic photographic printing apparatus, a reference color negative obtained by photographing a plurality of different reference colors is used. a chromaticity meter for measuring the chromaticity of the image displayed by the simulator and a reference print obtained by printing and developing the image using the automatic photo printing device under a constant light source condition; and each reference color of the image of the reference print. and the chromaticity of each reference color of the image of the simulator corresponding to each reference color on the chromaticity diagram. An automatic photo printing device equipped with a characteristic simulator parameter determining device. (2) The parameter calculation means calculates the value of the parameter that minimizes the sum of the distances by weighting a specific reference color.
An automatic photo printing device equipped with the simulator parameter determining device described in item 1). (3) The image displayed by the simulator is a CRT
An automatic photographic printing apparatus equipped with a simulator parameter determining apparatus according to claim 1 or claim 2, characterized in that measurement is performed using monochromatic red, green, and blue light emissions.