JPS6371837A - Image correction method for simulator used for automatic photographic printing device - Google Patents

Abstract

PURPOSE:To display a picture the same as a finished print with a changed exposure time given by inputting an amount by which exposure time is changed from an automatic exposure function in a simulator and displaying a picture electrically corresponding to the change. CONSTITUTION:Filter plates are paired, and to sets of them are arranged on both sides on the light beam projection side of a light source 10. A light dimming filter 14 consisting of plural complementary color filters and a mirror boxy 16 equipped with a scatter plate 14 are arranged in that order, and scattered light is projected on a color negative film 18. If the simulator 34 handles the film 18 that is below the dynamic range of the filter 14, photographing is made on a light beam transmissive side, and a picture on a CRT 345 is displayed so that it can be the same as that of the finished print. If the simulator 34 handles the film 18 exceeding the dynamic range of the filter 14, a CPU 48 controls the time when a shutter 22 is opened and closed to adjust the exposure time. If said time is changed, the picture is displayed by electrically calculating the change.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image correction method for a simulator for an automatic photo printer, and in particular to an image that is the same as a finished print printed on photographic paper by a color automatic photo printer. CRT
This invention relates to an image correction method for a simulator displayed above.

(Prior art) Conventionally, the product x transmission density (LATD) of the entire image of a color negative film is measured and the density)11 is corrected and slope control is performed to ensure that the density and color balance of all finished prints are the same as the negative. An automatic color photographic printing apparatus is known that prints and develops images to be the same regardless of density (n-light underexposure, proper exposure, 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. Place the color negative film on the negative carrier, turn on the light source, and open the black shutter for a predetermined time (keep the light time constant).
Printing is performed by forming an image of a color negative film onto photographic paper.

The printed photographic paper is developed in a developing process to automatically complete the print. In this automatic photo printing device, the light that has passed through the negative film is detected by a light receiving element, which allows red light (R) and green light (G) to be detected.
), primary colors are separated into blue light (B), density is controlled using LATD based on Evans' theorem, and color balance is controlled by performing slope control so that the slope is equal to the three primary colors. There is. Therefore, with this automatic photoprinter 'Zt 11, all of the normal finished prints will 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, a density area occurs.

Also, Lord IJ! When the color balance of the subject is different from the color balance of the background, for example, when the color of the main subject and the color of the background are complementary colors, color feria occurs. Therefore, even if density correction and slope control are performed, the finished state of the print may become poor. If the finished state of the print becomes poor in this way, it becomes necessary to perform printing and development again.

For this reason, in the past, as shown in Japanese Patent Application Laid-Open No. 53-46731, a color video signal was sent to the TV left camera to obtain the desired density and color balance while imaging the negative film and displaying the image on the TV screen. The so-called Photo Certification '2t1 is used in which the color video signal is adjusted and printed in an automatic photo printer using this color video signal. In addition, as shown in Japanese Patent Publication No. 42-25220, there is also a system in which an image of a negative film printed on photographic paper is displayed on a TV screen, and an automatic exposure machine is linked with a resistor for adjusting the brightness and contrast of the TV. be. In this way, the frequency of reprinting and development processing is reduced.

[Problem that the invention seeks to solve]

When printing an exposure amplifier or extremely overexposed negative using an automatic photo printing machine, the light intensity adjustment range of the light source using a light control filter is exceeded.In this case, the exposure time can be shortened using a black shutter. Or it will be controlled to extend. In this way, when the exposure time is shortened or extended using the shutter, the intensity of the light is not changed by the light control filter, so it is no longer possible to display the same image as the printed image just by capturing a color negative film. There was a problem.

Furthermore, when the exposure time is made very long, the amount of extension of the exposure time is determined taking reciprocity law failure into account, so that the print image and the displayed image become even more different.

The present invention has been made to solve the above problems, and provides an image correction method for a simulator for automatic photo printing equipment that can display the same image as the finished print even when the exposure time is changed by the shutter. The purpose is to provide

[Means for solving problems]

In order to achieve the above object, the present invention provides color negative printing using a light source controlled by an automatic exposure function of an automatic photographic printer equipped with a light control filter that controls the light source by the automatic exposure function and a shutter that adjusts the exposure time. The film is illuminated and the negative image recorded on the color negative film is captured.
In displaying the same image as the positive image of the print obtained from the color negative film as an image on the simulator for an automatic photoprinting device, the simulator calculates the amount of change in the image of the print corresponding to the amount by which the exposure time is changed by the shutter. The present invention is characterized in that the amount of change in exposure time is inputted from the automatic exposure function and displayed in electrical correspondence.

[Effect]

The simulator for automatic photo printing equipment related to the present invention is that when the color negative film does not exceed the dynamic range of the photochromic filter, the density and color balance can be adjusted by the photochromic filter! Jl After being adjusted, the light of the color negative film & it i! A color negative film is photographed from the i-side and displayed so that the image on the CRT is the same as the finished print image.

In the case of a color negative film that exceeds the dynamic range of the light control filter, the light quality irradiated onto the color negative film cannot be adjusted by the light control filter, so the exposure time is adjusted by controlling the opening and closing time of the shutter. When the exposure time is changed, the displayed image is electrically corrected in accordance with this change.

〔Effect of the invention〕

As explained above, according to the present invention, when printing requires changing the exposure time using the shutter, the simulator electrically corresponds to and corrects the displayed image according to this change, so that automatic photography is possible. The practicality of the simulator using the dimming function of the printing device can be improved. Furthermore, the exposure control system of an automatic photo printing apparatus including slope control can be used, and changes corresponding to reciprocity law failure can also be considered and displayed, making it possible to realize a highly accurate simulator. Correction for this correspondence can be electrically performed by inputting the amount of change over time of n-light in the automatic exposure function, and this has the effect that a low-cost simulator can be used.

〔Example〕

A simulator to which the present invention is applicable will be described in detail below with reference to the drawings. As shown in FIG. 1, a reflecting mirror 12 made of a cold mirror is arranged on the back side of a light source 10 made of a halogen lamp. A voltage of approximately 90% of the rated voltage is supplied to the light source 10 from a power supply device (not shown) in order to extend the life of the light source 10 and obtain a predetermined color temperature. 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.
After the light beam irradiated from the light source 10 is adjusted in color balance and light intensity by the dimmer filter 14, it is transferred to the mirror box 1.
6, the color negative film 18 held on the negative carrier is irradiated with the diffused light. 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 the illuminance needle, and adjust it to a constant light amount (t!! quasi-exposure exposure time) to the rated value. Adjust so that approximately 90% of the voltage is supplied.

An optical system 20 and a black shutter 22 are arranged in this order on the transmitted light beam exit side of the color negative film 18, and when the black shutter 22 is opened for a certain period of time, the light beams transmitted through the color negative film 18 form an image on the photographic paper 24 to form a print. Configured to expose 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 2o 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 11F32 equipped with a two-dimensional image sensor for detecting image density information of primary colors is arranged. This two-dimensional image sensor is composed of a CCD (charge coupled device). Note that the camera 3o is a CCD
It may also be configured with a single-chip camera.

Here, in a normal TV system, the γ of the TV is approximately 2.2, so a T correction circuit of γ-0.45 is installed in the TV camera so that r = 1 as a whole. Since γ of photographic paper is about γ-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.

The camera 30 is connected to a simulator 34 via a gain control circuit 33, and the image information detection device f
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. 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 C RT 34.5 that constitutes the simulator 34, and a chromaticity meter 44 is arranged to face the screen of the print 27. Total 42.4
4 is connected to the 110 port 46 that constitutes the computer. The computer is the above-mentioned I10 boat 46,
CPU 48, read-on memory (ROM) 50, random access memory (RAM) 52, digital-analog (D/A) converter 54, analog-digital (A/D
) It is composed of converters 56 and 58 and buses 60 such as data buses and control buses that connect these, and includes a gain control circuit 33, a simulator 34, a δ and γ correction circuit, and a printing system density calculation circuit 40. The drive circuit 29 is connected to the slope control circuit 62 and the drive circuit 26 connected to the 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 (0.7 Vl, which corresponds to the white level) is input. In order to adjust the gain of the camera 30 using this gain control circuit 33, a reference negative (so-called plain negative) obtained by developing unphotographed film is input. An image is captured by the camera 30, an analog signal is output from the D/A converter 54 for the camera output of each of the three primary colors R, G, and B, and gain adjustment is stopped when the signal is output from the flip-flop 333. By doing this, the white level of the camera can be adjusted when the blank is negative (when the transmitted light of the negative is at its maximum), so the brightness standard can be determined.

Also, store the camera's iris position and color balance position as digital values after the gain is adjusted as described above, and the amount of light will change as the negative size and magnification differ)
By creating channels for each negative size, switching can be performed simply by switching channels each time the negative size is changed.

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 and a G A signal processing circuit 62 which converts the signal into a density signal and performs δ and γ correction; and f7 which converts the B signal into a density signal and performs δ and γ correction.
It consists of a signal processing circuit 64. 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 is
Offset correction circuit 601, logarithmic conversion circuit 602 for converting density signals, δ correction circuit 603, and γ correction circuit 60
It consists of 4. 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 is an operational amplifier OP
4, resistors R6 and R7, and variable power supply B2. Then, the RSG and B signals are corrected by δ and γ and output.

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 (4 integrals) 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 to the analytical density of photographic paper, and converts the analytical density of the print to the phosphor of the CRT. It is constructed by sequentially connecting in series a luminance signal conversion circuit 344 that converts the luminance intensity of each color to the luminance H intensity, and a CRT 345 that causes a phosphor to develop a color according to the output of the luminance signal conversion circuit 344 and displays an image imaged by the camera 30. There is.

The drive circuit 26 moves each of the complementary color filters of the dimmer filter 14 in a direction perpendicular to the optical axis to adjust the color balance and light amount. Reciprocity law failure is established, and even if the exposure amount is appropriate, the exposure becomes insufficient and the density decreases. Therefore, the CPLI 48 calculates the difference between the optimum exposure amount and the current exposure amount in consideration of reciprocity law failure, and controls the opening time of the black shutter so that the exposure time is increased by the time corresponding to this difference. This increase in exposure time is calculated and then stored in the RAM 52.

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 integrated density of the color negative film image viewed from the spectral sensitivity of the camera is B 'tv s ' When C; ν and R'lV are converted to negative analytical density using a 3×3 matrix A-' (where -1 indicates an inverse matrix), the following equation is obtained.

In addition, if the integral density of a color negative film image viewed from the spectral sensitivity of photographic paper is B'P, G'F, and R'F, then the negative analysis is converted to degrees using a 3x3 matrix t; It becomes like this.

Negative analysis in equations (1) and (2) above 4 degrees (I3y
Since v-G□, R□) and (BP, Or, RF) are proportional, they are expressed by the following equation (3) using a diagonal matrix α whose diagonal components are proportional constants.

Therefore, using equations (1) to (3) above, (B; , G'
l · and the following equation (4) are obtained, thereby correcting the difference between the density seen by the spectral sensitivity of the TV and the density seen by the spectral sensitivity of the photographic paper.

Each component of each of the above matrices B1α is determined in advance for a sample such as a reference negative by considering the coloring characteristics of color negative film, the spectral sensitivity characteristics of photographic paper, and the spectral sensitivity characteristics of the camera, and the matrix shown below is 3×3. It is set in the matrix circuit 342.

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

The coordinate values of Y -yl -a (X -X+) - (6 squares, X+, yH are points that are not inverted in N/P and are hereinafter referred to as pivot points), x and y are the 7-degree area expressed in xy coordinates. The coordinate value a is a constant, and a negative value is usually selected.

As the pivot point, a point where the density should not change even if the N/P is reversed is selected. Cameras and CRTs display everything from the ring level to the white level at O ~ 0.7■, so if you take the logarithm of the video signal, the black level is approximately 0.
Therefore, for example, the black level may not be accurately inverted to the white level.

Therefore, for N/P inversion, camera output ■I,
It is preferable to perform N/P inversion using a pivot point near 23% of the white level of 1 (0.63 at 21 degrees excluding the negative base).

Figure 4 shows the camera output vI when N/P is inverted with 23% of the white level of camera output Vi and a as the pivot point.
Il and N/P inversion circuit 343 output ■. 1 is shown. Since the white level of the camera is 0.7■, 23% of the white level is 0.161 V. here,
The output of the 3×3 matrix circuit 342 is expressed as Y −3,2518+ 1 og V +11・= (
71, the coordinates corresponding to 23% of the white level are (
0,161,2,47), so (2,47,
2,47)? -2,47-a (x-2,47>...(8)
Converting the curve expressed by equation (7) above according to
The curve shown in FIG. 4 is obtained, which means that it has been N/P inverted. As understood from FIG. 4, the value of 23% of the daily level of the camera output remains unchanged even after the N/P inversion.

Furthermore, in order to perform N/P inversion, the N/P inversion circuit may be configured with the circuit shown in FIG. The circuit shown in the figure is an operating mechanism that changes the reference voltage by moving the operational amplifiers OPI, O20, the variable resistor R1 that sets the reference voltages Vx, Vy (corresponding to the pivot point) of the operational amplifier, and the contacts of the variable resistor R1. Equipped with AC. Resistor R2 is connected to the inverting input terminal of operational amplifier OPI.
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 0P20 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 R
One end of 1 is grounded, the other end is grounded via power supply B,
The contacts of the variable resistor R1 are connected to the non-inverting input terminals of the operational amplifiers OP1 and O20, respectively.

A method for determining the pivot point using the above circuit will be explained. First, 4! A color negative film that has developed a quasi-gray color is held between negative carriers, and a single image is taken by a camera. After N/P inversion is performed using the circuit shown in Figure 5, a standard gray signal is electrically generated to be displayed on a CRT screen. (This can be created by setting the white level of the CRT to 23%) and is displayed on the CRT screen in close proximity to the above negative image. and,
By operating the keyboard, the resistance value of the variable resistor R1 is continuously changed to change the reference voltages V, , V, and a negative image colored in standard gray is electrically created. 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 it is possible to set the gray level according to the sense of the measurer, it is possible to set the gray level according to the sense of the measurer. A gray level can be set for the gray level, thereby allowing highly accurate simulations to be performed, including conditions such as development conditions (fatigue of the developer, temperature change of the developer, etc.).

Since a CRT displays an image using a light emitting body, 1 degree in a 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. Furthermore, changing the amount of dye changes the chromaticity. The points change. 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- converts the output of the N/P inverting circuit 343 into the luminance luminance signal T of each color of the CRT according to the following equation, and outputs it to the CRT 345.

T = F (log-' (((D)) ) = 1
9, where f is a function that converts the output to integrated concentration, F
is a function that converts the integrated transmittance Ro g-' (D) into a signal of luminance.

The functions F and f are determined by predetermining optimal values for the output and luminance luminance signal T, and performing optimization using the least squares method, regression, or the like. Note that a 3×3 matrix is generally used as the functions F, , f.

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

Here, if the exposure time is changed due to reciprocity failure as described above, the change in exposure time is stored in the RAM 52.
By adjusting the output of the D/A converter 54 read from (The gain is reduced before N/P inversion) As a result, the same image as the print image is displayed on the CRT. Then, when the reciprocity law is established, the gain of the camera is returned to its original state. Note that at this time, a symbol indicating that the gain of the camera has been changed is displayed at a predetermined position on the CRT.

In the above, an example was explained in which the gain of the camera is controlled to correct the change in exposure time, but the change in exposure time can also be corrected by correcting the components of the matrix set in a 3 x 3 matrix circuit. You can do it like this.

[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.
Figure 4 is a circuit diagram showing an example of the δ and T correction circuit.
A diagram for explaining P inversion, and FIG. 5 is another circuit diagram for performing N/P inversion. 14...Dimmer filter, 27...Print, 34...Simulator.

Claims (2)

[Claims] (1) Color negative film is recorded by illuminating the color negative film with the light source controlled by the automatic exposure function of an automatic photo printer equipped with a light control filter that controls the light source using the automatic exposure function and a shutter that adjusts the exposure time. A print corresponding to the amount by which the exposure time is changed by the shutter when a negative image is captured and an image identical to the positive image of the print obtained from the color negative film is displayed as an image in a simulator for an automatic photoprinting device. An image correction method for a simulator for an automatic photoprinting apparatus, characterized in that the amount of change in the image is inputted into the simulator from the amount of change in exposure time from the automatic exposure function and displayed in electrical correspondence. (2) An image correction method for a simulator for an automatic photoprinting apparatus as set forth in claim (1), characterized in that when electrical correspondence is made, the change in the printed image due to reciprocity law failure is taken into account. .