JP2724140B2 - Image Correction Method for Simulator for Automatic Photo Printing Equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image correcting method for a simulator for an automatic photographic printing apparatus, and more particularly to an image identical to a finished print printed on photographic paper by a color automatic photographic printing apparatus. CRT
The present invention relates to a method for correcting an image of a simulator to be displayed above. [Prior art] Conventionally, the integrated transmission density (LATD) of the entire image of a color negative film has been measured to correct the density, and the slope control has been performed so that the density and color balance of all the finished prints are negative (exposure). 2. Description of the Related Art A color automatic photographic printing apparatus which performs printing and development so as to be the same regardless of under exposure, proper exposure, and overexposure is known. This automatic photographic printing device includes a light source, a dimming filter, a mirror box,
An optical system including a negative carrier and a black shutter is arranged in order. Printing is performed by placing a color negative film on a negative carrier, turning on a light source, opening a black shutter for a predetermined time (with a constant exposure time), and forming an image of the color negative film on photographic paper. The printed photographic paper is developed by a developing process so that the print is automatically finished. In this automatic photographic printing apparatus, light transmitted through a negative film is separated into red light (R), green light (G), and blue light (B) by a light-receiving element, and the density is determined using LATD based on Evans' theorem. And the slope balance is controlled so that the slopes of the three primary colors coincide with each other to control the color balance. Therefore, according to this automatic photographic printing apparatus, all of the normally finished prints have the same density and color balance. However, even if the main subject of the color negative film has an appropriate density, if the density of the background is high or low, the exposure amount is controlled under the influence of the density of the background, and a density area is generated. If the color balance of the main 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 have a complementary color relationship, a color area occurs. Therefore, even if the density correction or the slope control is performed, the print finish may be deteriorated. As described above, when the finished state of the print deteriorates, it is necessary to perform the printing development again. For this reason, conventionally, as disclosed in JP-A-53-46731, a color video signal is obtained so that a desired density and color balance can be obtained while taking an image of 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 an image is adjusted and an automatic photo printing device prints using the color video signal. In addition, as shown in Japanese Patent Publication No. 42-25220, an image of a negative film to be printed on photographic paper is displayed on a TV screen, and an automatic exposure machine is linked with a TV brightness and a resistance for contrast adjustment. is there. In this way, the frequency of the reprinting development process is reduced. [Problems to be Solved by the Invention] When printing an extremely underexposed or overexposed negative with an automatic photographic printing apparatus, the amount of light of the light source can be adjusted by a light control filter. In this case, the black shutter controls the exposure time so as to be shortened or extended. Thus, when shortening or extending the exposure time by the shutter,
Since the light intensity is not changed by the light control filter, there is a problem that the same image as the printed image cannot be displayed only by capturing the color negative film. Also, if the exposure time is very long, since the amount of extension of the exposure time is determined in consideration of the reciprocity failure,
The print image and the display image are further different. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an image correction method for a simulator for an automatic photographic printing apparatus capable of displaying the same image as a finished print even when the exposure time is changed by a shutter. The purpose is to do. [Means for Solving the Problems] In order to achieve the above object, the present invention provides an automatic exposure apparatus for an automatic photographic printing apparatus including a dimming filter for dimming a light source by an automatic exposure function and a shutter for adjusting an exposure time. The color negative film is illuminated with the light source that is dimmed by the function to capture the negative image recorded on the color negative film,
In displaying the same image as the positive image of the print obtained from the negative image recorded on the color negative film as the image of the automatic photographic printing device simulator, the image of the automatic photographic printing device simulator is obtained from the imaging of the negative image. Characteristics until the positive image of the print is obtained from the illumination of the negative image,
In order to obtain a positive image of the print using the light source, the automatic exposure function illuminates the negative film in the same dimming state as when the light source is dimmed by the dimming filter and is recorded on the color negative film. When the exposure time is changed by the shutter to exceed the light control range of the light control filter, the image change of the print corresponding to the change amount of the exposure time is taken. The simulator is characterized in that the amount of change in exposure time is input from the automatic exposure function and is electrically displayed. [Operation] The simulator for an automatic photographic printing apparatus according to the present invention is:
In order to obtain a positive image of a print in an automatic photographic printing device, the negative film is illuminated by the same dimming state when the light source is dimmed by the dimming filter by the automatic exposure function to illuminate the negative image recorded on the color negative film. Take an image. This simulator for an automatic photographic printing apparatus matches characteristics from capturing a negative image to obtaining an image of the simulator for an automatic photographic printing apparatus with characteristics from illumination of a negative image to obtaining a positive image of a print. . Therefore, when the density and the color balance are adjusted by the dimming filter, the dimming state in the simulator for the automatic photographic printing apparatus is the same as when a positive image of a print is obtained. In the case of a color negative film that does not exceed the dynamic range of the light control filter, the simulator for an automatic photographic printing apparatus takes an image of the color negative film from the light transmission side of the color negative film after the density and color balance are adjusted by the light control filter. Then, the image on the CRT is displayed so as to be the same as the image of the finished print. In the case of a color negative film that exceeds the dynamic range of the light control filter,
Since the light quality of the light irradiated on the color negative film cannot be adjusted by the light control filter, the exposure time is changed and adjusted when the light control range exceeds the light control range that can be controlled by the light control filter. That is, the exposure time is adjusted by controlling the opening and closing time of the shutter. When the exposure time is changed, an image to be displayed is corrected in accordance with the change so as to correspond electrically. [Effects of the Invention] As described above, according to the present invention, a light source for obtaining a positive image of a print and a light source for simulating are shared, and light control similar to that performed by a light control filter is performed. In addition to illuminating the negative film in this state, the characteristics from the imaging of the negative image to the acquisition of the image of the simulator match the characteristics from the illumination of the negative image to the acquisition of the positive image of the print. The characteristics of the print, including the development conditions, etc., in an automatic photographic printing device
It is possible to match the color development characteristics and simulate the image of the simulator that matches the print.
At the same time, in the case of a print that requires changing the exposure time to exceed the light control range of the light control filter, the image displayed according to this change is electrically correlated by a simulator and corrected. It is possible to accurately simulate a difference in light control range due to a change in time, and to improve the practicality of a simulator using the light control function of an automatic photographic printing apparatus. In addition, an exposure control system of an automatic photographic printing apparatus including a slope control can be used, and a display can be displayed in consideration of a change corresponding to reciprocity failure at the time of printing, and a highly accurate simulator can be realized. Correction for this response can be electrically performed by inputting the amount of change in the exposure time of the automatic exposure function, thereby providing a low-cost and high-precision simulator. Embodiment A simulator to which the present invention can be applied will be described below in detail with reference to the drawings. As shown in FIG. 1, a reflecting mirror 12 composed of a cold mirror is arranged behind a light source 10 composed of a halogen lamp. The light source 10 includes a light source
In order to extend the service life of 10 and obtain a predetermined color temperature,
A voltage of approximately 90% of the rated voltage is supplied from a power supply device (not shown). On the light-irradiation side of the light source 10, Y (yellow), M (Y) are formed by combining two fan-shaped filter plates of approximately 1/4 circle formed in a logarithmic curve and arranging them in a pair of right and left. A light control filter 14 comprising three complementary color filters of magenta) and C (cyan) and a mirror box 16 provided with a scattering plate are arranged in order, and the light emitted from the light source 10 is used for color balance and light control by the light control filter 14. After the light amount is adjusted, it is converted into uniform diffused light by the mirror box 16 and held in a negative carrier.
It is configured to irradiate the diffused light 18. To adjust the above light source voltage, set each complementary color filter of the dimming filter at the mechanical center, measure the light amount with an illuminometer, and adjust it to a constant light amount (standard exposure time). Adjust so that 90% voltage is supplied. On the transmitted light exit side of the color negative film 18, an optical system 20 and a black shutter 22 are arranged in order, and the black shutter 22 is opened for a predetermined time to form an image on a photographic paper 24 by the light transmitted through the color negative film 18 to print the photographic paper. It is configured to expose. The exposed photographic paper 24 is processed into a print 27 after being processed in a developing process 25. A drive circuit 26 is connected to the dimming filter 14, and
The color balance and the light amount can be adjusted by moving each of the complementary color filters in a direction perpendicular to the optical axis by the drive circuit 26. The drive circuit 29 is connected to the black shutter 22. In the vicinity of the optical system 20 side of the color negative film 18, R
3 provided with three filters respectively transmitting (red) light, G (green) light and B (blue) light, and outputting R, G, B signals
A camera 30 composed of a plate camera and an image information detecting device 32 having a two-dimensional image sensor for detecting image density information of three primary colors of R, G and B are arranged. This two-dimensional image sensor is constituted by a CCD (charge coupled device). Note that the camera 30 may be configured by a CCD single-chip camera. Here, in a normal TV system, since γ of the TV is about 2.2, the γ correction circuit of γ = 0.45 is provided in the TV camera so that γ = 1 as a whole. Since γ is approximately 2.0, in the present embodiment, γ in the simulator is set to approximately 1 without providing a γ correction circuit in the camera 30. The camera 30 is connected to a simulator via a gain control circuit 33.
The image information detection device 32 is connected to a slope control circuit 62 via a δ and γ correction circuit 38 and a print density calculation circuit 40. The above-described color balance and density correction are performed by the print system density calculation circuit 40 and the slope control circuit 62. Further, the chromaticity meter 42 is arranged so as to face the screen of the CRT 345 constituting the
A chromaticity meter 44 is arranged so as to face the 27 screen.
The chromaticity meters 42 and 44 are connected to an I / O port 46 constituting a computer. The computer is connected to I / O port 4 above
6, CPU 48, read-on memory (ROM) 50, random access memory (RAM) 52, digital-analog (D / A) converter 54, analog-digital (A / D) converters 56 and 58, and connect these It is configured to include a bus 60 such as a data bus and a control bus, and includes a gain control circuit 33, a simulator 34, a δ, γ correction circuit 38, a print system density calculation circuit.
It is connected to the slope control circuit 62 and the drive circuit 62 connected to 40 and to the drive circuit 29. The gain control circuit 33 includes, as shown in FIG.
331, operational amplifier 332, flip-flop 333 and resistor 3
The reference voltage (0.7 V corresponding to the white level) is input to one input terminal of the operational amplifier 332 via the resistor 336. In order to adjust the gain of the camera 30 by the gain control circuit 33, a reference negative (a so-called plain negative) obtained by developing an unphotographed film is imaged by the camera 30, and the R, G, and B primary color camera outputs are taken. The analog signal is output from the D / A converter 54 and the flip-flop 33
This is performed by stopping the gain adjustment when the signal is output from 3. Accordingly, the white level of the camera can be adjusted when the image is a transparent negative (when the transmitted light of the negative is maximum), so that the reference of the brightness can be determined. If the iris position and the color balance position of the camera after the gain is adjusted as described above are stored as digital values and channelized for each negative size (the light amount changes because the magnification is different), the negative size can be obtained. The switching can be performed only by switching the channel every time is changed.
By doing so, even if the negative size is changed, the iris position and the color balance position of the camera can be switched only by switching the channel. In the above case, if the light source is deviated from the standard state, it is necessary to electrically correct the deviated portion. Therefore, it is preferable to adjust the standard light source in a light source state in which a standard gray negative is finished in a standard gray print. As shown in FIG. 3, the δ and γ correction circuit 38 converts the R signal output from the image information detecting device 32 into a density signal to perform δ and γ correction, and converts the G signal into a density signal. And a signal processing circuit 64 for converting the B signal into a density signal and correcting for δ and γ. 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 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.
It is composed of The δ correction circuit 603 includes an operational amplifier OP4,
It comprises 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. The above-described simulator 34 is a logarithmic converter 341 connected to the output terminal of the gain control circuit 33, and corrects a difference between the density (integrated density) viewed from the spectral sensitivity of the camera and the density viewed from the spectral sensitivity of the photographic paper. × 3 matrix (third-order square matrix) circuit 34
2. N / P inversion circuit 343 for inverting negative / positive (N / P) and converting to analytic density of photographic paper, luminance signal conversion circuit for converting analytical density of print to emission density of each color of CRT phosphor A CRT 345 for displaying an image captured by the camera 30 by coloring a phosphor in accordance with the output of the 344 and the luminance signal conversion circuit 344 is connected in series. The drive circuit 26 adjusts the color balance and the amount of light by moving the complementary color filters of the dimming filter 14 in the direction perpendicular to the optical axis, respectively, but in the case of a negative film that is extremely overexposed or a negative film that is extremely underexposed. Means that reciprocity failure is established, and even if the exposure amount is appropriate, the exposure is insufficient and the density is reduced. For this reason, the CPU 48 calculates the difference between the optimal exposure amount and the current exposure amount in consideration of reciprocity failure, and controls the opening time of the black shutter so that the time exposure time corresponding to this difference becomes longer. This increase in the exposure time is stored in the RAM 52 after being calculated. Correction of received light spectral characteristics Here, the value obtained by logarithmically converting each of the B, G, and R signals output from camera 30 by logarithmic conversion circuit 341, that is, the integrated density of the color negative film image as viewed from the spectral sensitivity of the camera is represented by B ′ _TV. , G ' _TV and R' _TV as 3 × 3 matrix A ^-1
(However, -1 indicates an inverse matrix) is converted into a negative analytical density as follows. Also, the integration density of the color negative film image viewed by the spectral sensitivity of the printing paper B _P, G _P, 3 a R _P × 3 the matrix B ^-1
Is converted into a negative analytical density using the following equation. Since the negative analytical density (B _TV , G _TV , R _TV ) in the above equations (1) and (2) is proportional to (B _P , _GP , R _P ), the diagonal with the diagonal component as a proportional constant It is expressed by the following equation (3) using the matrix α. Therefore, using the above equations (1) to (3), (B _P , G _P ,
When the relationship between (R _P ) and (B _TV , G _TV , R _TV ) is obtained, the following equation (4) is obtained, whereby the density between the TV spectral sensitivity and the photographic paper spectral sensitivity is obtained. Differences are corrected. However, It is. The respective components of the matrixes B, α, and A are obtained in advance for a sample such as a reference negative in consideration of the color developing characteristics of a color negative film, the spectral sensitivity characteristics of photographic paper, and the spectral sensitivity characteristics of a camera. It is set in the × 3 matrix circuit 342. The negative / positive inversion N / P inversion circuit 343 is a circuit for converting γ to −γ, and converts and outputs the output of the 3 × 3 matrix circuit 342 according to the following straight line. y−y ₁ = a (x−x ₁ ) (6) where x ₁ and y ₁ are coordinate values of a point not to be N / P inverted (hereinafter referred to as a “pipot point”), and x and y are xy coordinates of a density area. The coordinate value a when expressed is a constant and usually a negative value is selected. A point at which the density must not change even after N / P inversion is selected as the above-mentioned pivot point. Since the camera and the CRT display from black level to white level at 0 to 0.7 V, when the logarithm of the video signal is taken, black level 0 becomes -∞, for example, black level cannot be exactly inverted to white level. Sometimes. Therefore, when the N / P inversion, 23% of white level of the camera output V _in preferably N / P inversion (concentration at 0.63, excluding the base content of the negative) near the Pipotsuto point. The fourth figure, the relationship between the camera output V _in the N / P inverting circuit 343 outputs V _out when the N / P reverse the 23% white level of the camera output V _in the Pipotsuto point is shown. Since the white level of the camera is 0.7V, 23% of the white level is 0.161V
become. Here, if the output of the 3 × 3 matrix circuit 342 is expressed as y = 3.2518 + logV _in (7), the coordinates corresponding to 23% of the white level are (0.161,
2.47). Then, when the curve represented by the above equation (7) is converted according to the following equation, a straight line y−2.47 = a (x−2.47) (8) passing through (2.47, 2.47),
The curve shown in FIG. 4 is obtained, and the N / P is inverted. As understood from FIG. 4, the value of 23% of the white level of the camera output does not change even after the N / P inversion. In order to perform the N / P inversion, the N / P inversion circuit may be constituted by the circuit shown in FIG. 5, and the N / P inversion may be performed by obtaining a pivot point as described below. Circuit of FIG. 5 is the operational amplifiers OP1, OP2, and the reference voltage by moving the contacts of the variable resistor R1 and the variable resistor R1 sets the reference voltage V _x of operational amplifier, V _y (corresponding to Pipotsuto point) It has an operating mechanism AC for changing. A signal is input to the inverting input terminal of the operational amplifier OP1 via the resistor R2, and a variable resistor R3 for adjusting a gain is connected between the inverting input terminal and the output terminal of the operational amplifier OP1. The output terminal of the operational amplifier OP1 is connected to the inverting input terminal of the operational amplifier OP2 via the resistor R4. The resistor R5 is connected between the inverting input terminal and the output terminal of the operational amplifier OP2. Variable resistor
One end of R1 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 OP2, respectively. A method of obtaining a pivot point using the above circuit will be described. First, a color negative film that has developed into a standard gray is sandwiched between negative carriers, captured by a camera, and subjected to N / P inversion by the circuit in FIG. 5 and then displayed on a CRT screen. Next, a standard gray signal is created electrically (can be created by setting the white level of the CRT to 23%) and displayed on the CRT screen in close proximity to the negative image. Then, the image by continuously altered so by the reference voltage V _x the resistance value of the variable resistor R1 by operating the keyboard, by changing the V _y, electrically created standard gray signal image by color negatives to the standard gray To match. Thus, the pivot point is determined. By using the circuit as described above, the gray level can be set according to the sense of the measurer, and the gray level can be set according to the sense of the measurer. The gray level can be set, whereby a highly accurate simulation can be performed, including the state of development conditions (fatigue of the developer and the like, temperature change of the developer and the like). Correction of Color Spectral Characteristics Since the CRT displays an image using a luminous body, the brightness of the CRT is proportional to the voltage. However, since the print uses an absorber (dye), the amount of dye and the logarithm of the brightness are not proportional to the amount of dye and the luminance, and the chromaticity point changes when the amount of dye is further changed. I do. That is, the dye of the print is an unstable primary color (C, Y, M) whose chromaticity point changes with a change in the amount of the dye. Therefore, the luminance signal conversion circuit 344 calculates N / P according to the following equation.
The output D of the inverting circuit 344 is converted into a light emission luminance signal T of each formula of the CRT and output to the CRT 345. T = F (log ⁻¹ (f (D))) (9) where f is a function of converting the output D into an integrated density, and F is converting the integrated transmittance log ⁻¹ (D) into a signal of emission luminance. Function. The functions F and f are determined by determining the output D and the emission luminance signal T to optimal values in advance and performing optimization by the least square method, regression, or the like. In general, a 3 × 3 matrix is used as 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 an image having color development characteristics matching the color development characteristics of the print is displayed on the CRT. Here, if the exposure time is changed due to reciprocity failure as described above, the change in the exposure time is read from the RAM 52 and the output of the D / A converter 54 is adjusted to change the gain of the camera. (If the exposure time is lengthened, N /
(The gain is increased before the P inversion, and the gain is decreased before the N / P inversion if the exposure time is shortened.) Thus, the same image as the print image is displayed on the CRT. And
When the reciprocity law is established, the gain of the camera is returned to the original state. 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 description, an example in which the conversion of the exposure time is corrected by controlling the gain of the camera has been described. However, the component of the matrix set in the 3 × 3 matrix circuit is corrected to correct the change in the exposure time. You may do so.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a gain control circuit in FIG. 1, and FIG.
FIG. 4 is a circuit diagram showing an example of the δ and γ correction circuit, and FIG.
FIG. 5 is another circuit diagram for performing N / P inversion. 14 ... dimming filter, 27 ... print, 34 ... simulator.

Claims (1)

(57) [Claims] A negative recorded on a color negative film by illuminating a color negative film with a light source dimmed by an automatic exposure function of an automatic photographic printing apparatus equipped with a dimming filter for dimming a light source by an automatic exposure function and a shutter for adjusting an exposure time. In capturing an image and displaying the same image as a positive image of a print obtained from the negative image recorded on the color negative film as an image of an automatic photographic printing device simulator, from the imaging of the negative image to an automatic photographic printing device The automatic exposure function is used to match the characteristics of the simulator until the image is obtained until the positive image of the print is obtained from the illumination of the negative image, and to obtain a positive image of the print using the light source. Illuminating the negative film in the same dimming state as when dimming the light source with the dimming filter. When a negative image recorded on the color negative film is taken and the exposure time is changed by the shutter to exceed the light control range of the light control filter, a print corresponding to the change amount of the exposure time is required. Wherein the image change amount is input from the automatic exposure function in the simulator and electrically displayed so as to correspond to the exposure time change amount, and the image correction method for a simulator for an automatic photographic printing apparatus. 2. 2. The image correction method for a simulator for an automatic photographic printing apparatus according to claim 1, wherein when the electric image is made to correspond electrically, a change in the printed image due to reciprocity failure is taken into account.