JPH0640190B2 - Method for determining exposure for photo printing - Google Patents

Description

The present invention relates to a method for determining a photographic printing exposure amount.

The exposure amount for printing a color film is normally determined by LATD (average transmission density over the entire screen). However, the exposure amount determined by this LATD can only satisfy about 70% of the total, and the operator can use the negative film before the LATD photometry (before the exposure on the exposure opening surface of the preliminary inspection device or printer). Observe, determine the corrected exposure amount (using normal density key, color key, function key, color correction key, etc.) for LATD exposure based on the relationship between the main part and the background and the pattern learned from experience, and The exposure is performed by adding. FIG. 1 shows an example of the relationship between the correction key by classification and the exposure amount corresponding to it. The correction key is the basic exposure amount (usually LATD)
The corrected exposure dose for the standard exposure dose is usually given.
Use the ~ 15-step correction key (density key). As a result of investigating the deviation from the optimum corrected exposure amount based on the usage situation of the correction keys by many skilled and unskilled people, the skilled worker shows that the optimum corrected exposure amount (0%) is within ± 50% as shown in FIG. 98% of the frames are included, but ± 70 for unskilled people
It has fallen to the% level. In FIG. 2, the characteristic I shows the skilled person and the characteristic II shows the unskilled person with respect to the one requiring the correction of the exposure amount for the LATD exposure. Further, both the expert and the non-skilled person tend to have a shortage in comparison with the optimum corrected exposure amount, but the non-skilled person has a larger shortage amount, and the increase in the corrected exposure amount causes a variation than the decrease. There is a tendency to be easy. As described above, there is a big difference between a skilled person and a non-skilled person, long experience (several years) is required to become skilled, and print quality obtained between individuals or due to fatigue and the like easily varies.
There is a drawback that working conditions such as nighttime are also greatly restricted. In addition, there are drawbacks such as loss of experience due to job changes and retirement after long training, and the reality is that there is a search for a departure from this method.

As a solution to this problem, an automatic determination method has been proposed in which the film screen is divided into small pixels, photoelectrically scanned, and the exposure amount is determined by analyzing the density value obtained from that and combining the data. However, such fully automatic correction does not provide sufficiently satisfactory quality for all prints. Therefore, in Japanese Patent Laid-Open No. 51-150336, density feria and overexposure and underexposure are identified and the classification information is manually stored. When the average density is high, the minimum density of the shadow part is low and the average density is low. The exposure amount is sometimes determined by obtaining the maximum density of the highlight portion. In other words, by designating the density ferria by visual judgment, the overexposed and underexposed images are removed, and when the average density is high, the exposure amount is determined at the lowest density, assuming that the shadow part has a subject. However, when the average density is high, it cannot always be said that the shadow part has a subject,
Even if there is a subject in the shadow portion, determining the exposure amount with the lowest density causes a great error. I mean,
This is because the minimum density is often equal to the fog density of the image and has little relevance to the subject. In addition, JP-A-52
In the inspection device shown in No. 62428, the reverse position and the vertical position of the film image are rotated by 90 ° or 180 ° by visual judgment, and the circuit is switched by pushing the button so as to be in the normal position. However, this method does not obtain the feature amount in relation to the main part, but merely rotates the feature amount to bring it into the normal position.

Furthermore, the density correction amount based on the scanning data is predicted to correct the automatic determination result (Japanese Patent Laid-Open No. 48-98821,
Japanese Patent Application Laid-Open No. 52-62429) is already known, but it has the drawback that it requires two judgments, that is, whether the correction is necessary or not, and the amount of correction. And the processing capacity does not increase. Especially, it is very difficult to predict a complicated calculation result of automatic determination. Then, as an improvement of the correction amount determination, the scene type information (for example, strobe, open scene, snow, etc.) is visually determined for a scene that is not good at automatic determination, and the automatic determination result is corrected by a predetermined amount depending on the scene type. It is also possible to do it. However, in automatic determination, the density of strobe negative generally tends to be insufficient, but there are many normal ones and too many dark ones, which may cause overcorrection. Further, the above-mentioned scene type information has drawbacks that the definition of a scene tends to vary among individuals and that it is necessary to assume a large number of scenes. For example, a strobe scene should be considered as a completely different type if the background is a white wall, if the background is furniture, if the background is darkness, and if it is close-up photography. This is due to the lack of information on the main part.

As described above, the visual determination information is input in the conventional automatic determination method on the premise that the automatic determination unit automatically determines, and in the case of inconvenience, it is only a supplementary input of the correction amount of the automatic determination. Since it does not exist, its effect is limited. In addition, since the visual judgment information does not include the scene information and the density information of the main part appearing on the negative film, the visual judgment information has a small effect and the obtained improvement rate is small. As described above, it can be said that the fully automatic determination and the assistance of the fully automatic determination and the visual determination information have not reached the range of quickly producing a high-quality, low-priced print at the present moment. In a small photo lab, it is more important to have a method that allows even an unskilled person to produce a high-quality, high-acceptance print at a constant rate. The proposal of the printing method is requested.

From the above, the object of the present invention is that even a non-skilled person or a beginner can obtain a high print passing rate by the operation of the automatic determination section, and even an expert can operate the automatic determination section.
This is to enable printing with higher quality and higher acceptance rate than ever before. Further, it is also intended to reduce the fatigue of the visual judgment work and improve the processing capacity.

The present invention will be described below.

FIG. 3 shows an example of the method of the present invention, in which a negative film (subject) is divided into a large number of small areas for scanning (1), and the scanning 1 is used to determine the LATD, the maximum density, and the minimum of the negative film screen. The characteristic value 2 such as the density is obtained, the negative film is classified by the visual judgment 3 of the operator, and the negative film is input using the correction key. The classification 4 of the negative film may be based on the information of the visual judgment 3 input by the correction key, or may be classified by including the information and the characteristic value 2 obtained by the scanning 1. The classification 4 is set in advance. The calculation formula for determining the exposure amount is selected, and the exposure amount is determined by using the characteristic value 2 with the selected calculation formula.
(6). This may be used as it is as visual judgment information, but at least for non-experts to perform high-speed processing with a high pass rate.
Exposure rate change rate of 60% or more (preferably 100% or more),
It is good to classify into 6 or less (desirably 4 or less).
Further, the calculation 5 includes, for example, Japanese Patent Application Laid-Open Nos. 54-28131 and 52
No. 23936, a known arithmetic expression is used, and the coefficient and the characteristic value to be used of the preset arithmetic expression are different according to the classification 4. That is, the visual judgment 3 is used to perform a large classification based on the exposure correction value, and the key (for example, the correction key) is used for input, and the accurate density correction amount is calculated from the characteristic value 2 of the scanning 1.

FIG. 4 shows the relationship between the classification by the visual judgment 3 of the present invention and the selection of the set arithmetic expression. Four kinds of arithmetic expressions (a to d expressions) are stored and the classification result is stored. CL1-C
The arithmetic expressions a to d are selected according to L4. Therefore, when the classification of the negative film is in the range of CL3, for example, the formula c is used to calculate the exposure amount, and the characteristic value 2 obtained by the scanning 1 is substituted into this formula c to obtain the exposure amount obtained. The negative film is printed. In the conventional method (FIG. 1), the exposure change amount is fixed with respect to the classification (correction key), whereas in the present invention, the exposure change amount is plus or minus depending on the subject (that is, according to the arithmetic expression) for each classification. It has the characteristic of changing by 30% or more.

Next, an example of the pass rate when the above method is actually used is as follows. The reason why the correction amount ranges overlap is to increase the permissible range of misidentification.

Here, since the pass rate of the expert's determination was 91.4%, it can be seen that this method provides a higher pass rate and higher quality than the conventional visual determination. Moreover, since the determination work is easier than before, work efficiency is improved and individual differences can be reduced.

In this way, the calculation formulas (a formula to d formula) are used so that accurate calculation can be performed even if there is some misunderstanding in the classification by visual judgment.
Since the areas covered by are overlapped, it is possible to reduce errors in visual judgment. Further, as compared with the conventional density key operation with a change rate of 15 to 30% as shown in FIG. 1 (stepwise correction), the exposure amount is directly obtained by an arithmetic expression directly related to the subject, so that the accuracy is improved. At the same time, variations in density due to correction mistakes are reduced, and a printer of excellent quality can be obtained. Furthermore, since the number of classifications is much smaller than in the conventional case, even unskilled people can exhibit high performance. If the number of classifications is increased, the operator is likely to make a mistake in classification, which is unlikely to lead to an increase in the pass rate, and an unskilled person conversely reduces the pass rate.

Therefore, if the scenes corresponding to the exposure correction area that covers a change rate of 60% or more (preferably 100% or more) are classified into the same classification, and then an appropriate correction exposure amount with respect to the basic exposure amount is calculated by an arithmetic expression. good. In addition, although the above description is based on the corrected exposure amount for ease of description, a scene in which the exposure amount is reduced for the subject group (i),
Scenes that do not require modification of the above-mentioned subject group (ii),
The subject group (iii) may be classified as a scene in which the correction amount is increased, and the subject group (iv) may be classified as a scene in which the exposure amount is greatly increased.

By the way, the corrected exposure amount is determined by the main subject and the background, and since this judgment has been used as it is for the correction, it causes the individual difference and the difficulty of the judgment as described above. However, since the present invention uses the corrected exposure amount by visual judgment as the classification information, it does not require such accuracy, and the corrected exposure amount used for determining the exposure amount is calculated from the exposure calculation formula to obtain a high print quality. You can get a pass rate. By using the classification information corresponding to the corrected exposure amount, it is possible to collect scenes having a similar relationship between the main subject density and the background density, and statistically determine the characteristic value and coefficient in such a scene. This can dramatically improve the accuracy of the exposure calculation formula. As an application of the present invention, relative density information of the main part such that the main part exists in the highlight part, the shadow part, and the middle part can be input as the visual determination information. It is also possible to input unnecessary portion information such as shadow, highlight and shadow, and neither highlight nor shadow. Furthermore, scanning data can be used for classification in addition to visual judgment information, and as its characteristic values, for example, contrast information, screen position density information (for example, screen center density), skin information, screen color information, main part or Unnecessary part information is considered. When the contrast information and the skin information are used, the processing is, for example, as shown in FIG. That is, the a formula is divided into a1 formula and a2 formula according to the presence or absence of contrast, and the b formula is divided according to the presence or absence of skin.
It is divided into b1 formula and b2 formula, and when it is judged that the a formula is selected in step S1, the presence or absence of contrast is judged (step S4). If there is contrast, the a1 formula is used, and if there is no contrast, the a2 formula is used. To use. Similarly, after it is determined in step S2 that the expression b is selected, the presence or absence of the skin is determined (step S3). If the skin is present, the expression b1 is used. If the skin is not present, the expression b2 is used. Then, in step S5, it is determined whether the expression c or the expression d is selected. The visual judgment information in the present invention may be input by a correction key or may be input from a magnetic memory or the like.

By the way, as described above, the corrected exposure information (the degree of increase / decrease) with respect to the basic exposure amount is used as the visual judgment information. Since it spreads to about 70%, it is preferable to prepare an exposure calculation formula with different accuracy of the classification information to be judged and use it according to each expert. The following is the experimental data for the case of passing the exposure within the optimum value ± 30% for a negative having 2000 frames.

Level A above is for experienced users, Level B and Level C
Defines the criterion for beginners by the corrected exposure amount. Level A is a case where the definition of an input group and high determination accuracy between groups are required, and Level B is a case where the definition of an input group and high determination accuracy between groups are lowered. The level C is for beginners who have further deteriorated the determination accuracy of necessity of correction. Here, the passing rate by the conventional method of the skilled person is 91.4%, the level A can produce higher quality prints than the conventional method, and the beginner can use the arithmetic expression of the correction amount range of the level C. It will be possible to obtain performance close to that of an expert.

Therefore, according to the present invention, as shown in FIG. 6, it is possible to select the program (7) of level A to level according to the skilled person such as the operator who visually judges the negative film 3. Good. Therefore, if the mode of level A to level C is selected and input before the printing operation, the exposure calculation formula suitable for one's skill is selected and the exposure amount is determined. FIG. 7 shows this state, and the expert selects one of the arithmetic expressions Aa to Ad defined in the correction amount range of level A in steps S11 to S13,
The exposure amount is determined by using the selected arithmetic expression, and the beginner selects the Ca formula to the Cd formula in accordance with the correction amount in the range predetermined in the level C in steps S30 to S32, and thereby the exposure amount is selected. Is calculated. In addition, a person located between the beginner and the expert specifies the level B, selects one of the exposure calculation formula Ba formula to Bd formula in steps S20 to S23, and determines the exposure amount by the calculation formula. become.

Further, in the above-mentioned levels A to C, the corrected exposure amount is shown to facilitate the description, but in actuality, classification and input may be made according to the following criteria.

(1) Group that reduces the corrected exposure dose ... Backlight, snow, low contrast scene, etc. (2) Group that does not change the corrected exposure dose ... Normal scene (3) Group that increases the corrected exposure dose ... Strobe, scene with dark background (4) A group that greatly increases the corrected exposure dose ... Strobes, fireworks, etc. in a dark place The above classifications A to C are C → B → according to the skill level of the operator.
It suffices to change the program in the order of A. By this method, suitable use can be made for a developer having a wide range of technical layers and an operator having a wide range of experience.

A calculation process for determining the exposure amount is disclosed in, for example, Japanese Patent Laid-Open No. 52-23936.
And those disclosed in JP-A-54-28131. All of these calculation processes are performed by using the exposure calculation formula defined by the statistical method, using the characteristic value obtained from the scanning data, and as a result, the exposure amount determination performance tends to be as shown in FIG. Has become. That is, the horizontal axis represents the correction exposure amount, the distribution ratio of the correction amount is as shown in the characteristic curve III, and the NG rate (fail rate) is low at the high distribution ratio of the correction amount. It is clear that the lower the distribution rate, the higher the NG rate correspondingly. This is because the calculation formula is optimized by the statistical method, so the corrected exposure dose "0" with the largest number of samples
The calculation results in the vicinity are very good. The correction area that gives a high pass rate is from "-2" (-50%) to "+2" (+50
%), Which occupies 85% of the whole, and the shaded area in FIG. 8 indicates this. Therefore, it is understood that the remaining 15% should be corrected with high accuracy.

From this, according to the present invention, the exposure amount is automatically determined by measuring the negative film, and the exposure amount calculation formula is selected based on the classification information of the visual determination information, and then the exposure amount is calculated. You may divide it into one. For example, the 8th
Only the shaded areas in the figure are subject to automatic determination. FIG. 9 shows an example of the processing, in which “0” is generated for classification in which classification information for visual judgment is not input, and automatic judgment is performed.
When the signal is "-1", it is determined that the negative group requires the reduction of the corrected exposure amount, and the determination formula 1 is used. Also,
When the signal is "1", it is determined as a negative group that requires an increase in the correction exposure amount, the determination formula 2 is used, and the signal is "1".
In other cases, for example, when it is “2”, it is determined that the negative group requires a large increase in the corrected exposure amount, and the determination formula 3 is used. This makes it possible to determine an appropriate exposure amount in consideration of the correction amount distribution rate as shown in FIG. A conventionally known method inputs a correction amount of a specific pattern before or after the automatic determination, with respect to the result of the automatic determination. However, since the conventional correction method uses the arithmetic expression of the automatic judgment as it is, the effect of the correction cannot be obtained, and it is easy to overcorrect the one for which a normal judgment result is obtained, and it is very difficult to judge the suitability of the correction. . However, as in the present invention, "correction key <-2 (-30
%) ”For the negative group (judgment formula 1),“ +2
(+ 30%) <correction key <+6 (+ 130%) ”for the negative group arithmetic expression (judgment formula 2),“ correction key> +5 (+110
%) ”, The judgment performance becomes extremely high by using another judgment formula such as the calculation formula (judgment formula 3) for the negative group.
As described above, even a person with little experience can obtain a high print acceptance rate with a small amount of visual determination information.

It should be noted that instead of using a plurality of correction exposure amount calculation expressions corresponding to the correction keys, a plurality of correction exposure amount calculation terms are included in one calculation expression, and one of these calculation terms is changed by the correction key.
Select one (for example, the arithmetic expression is the above-mentioned judgment expressions 1, 2, 3
Is set as each term, and when the correction key <-2 is input, the coefficient of the judgment term 1 is used as 1 and the coefficients of the judgment terms 2 and 3 are not used as 0 respectively. ) May be performed, and substantially different operations are performed corresponding to the correction keys.

Further, according to another method of the present invention, the visual judgment information is input, the film screen is divided into a large number of small areas for photometry, and the visual judgment information is obtained by changing the calculation method of the object feature amount (characteristic value). The exposure amount may be calculated using the characteristic values.

For example, when it is determined that the negative group reduces the corrected exposure amount,
The main part exists on the shadow side of the image, and the information on the highlight side is not mainly required, and the feature amount may be obtained by excluding that part. In this way, it is possible to obtain a higher pass rate and a higher-quality print by automatically making a determination using the feature amount in consideration of the subject density.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a conventional method for determining a printing exposure amount, FIG. 2 is a diagram for explaining a difference in correction amount between a skilled person and an unskilled person, and FIG. 3 is a diagram for explaining the present invention. FIG. 4 is a flow chart for explaining the principle of the present invention, FIG. 5 is a flow chart for explaining another example of the present invention, and FIG. 6 is another process example of the present invention. FIG. 7 is a flow chart showing the process, FIG. 7 is a flow chart showing the operation example,
FIG. 8 is a characteristic diagram for explaining automatic determination, and FIG. 9 is a flowchart showing still another processing example of the present invention. 1 ... Scanning, 2 ... Characteristic value, 3 ... Visual judgment, 4 ... Classification, 5 ... Calculation, 6 ... Exposure amount determination, 7 ... Program selection, S1-S5, S10-S13, S20-S23, S30-S32, S40 ~ S42
… Processing steps, CL1 to CL4… Classification areas.

Claims (9)

[Claims] 1. A method of determining a corrected exposure amount to an exposure amount based on an average density obtained by photometrically measuring a photographic film, and correcting the exposure amount to determine a photographic printing exposure amount, wherein the exposure amount is corrected. A plurality of correction keys for preparing the correction exposure amount are prepared, and a correction exposure amount calculation formula using characteristic values such as average density, maximum density and minimum density obtained from photometric values for calculating the correction exposure amount for each correction key is prepared. The film to be printed is measured, and the correction key is input according to the result of the visual judgment of the film image to be printed, and the corrected exposure amount calculation formula corresponding to the input correction key is read out, and the photometry is performed. The corrected exposure amount is obtained by substituting the characteristic value obtained from the value for calculation, and the exposure amount based on the average density is corrected by the corrected exposure amount to determine the printing exposure amount. Photographic printing exposure amount determining how to butterflies. 2. The corrected exposure amount calculation formula is statistically calculated by using characteristic values such as an average density, a maximum density and a minimum density obtained from the photometric value for a film grouped by an appropriate corrected exposure amount. The photographic printing exposure amount method according to claim 1, wherein the photographic printing exposure amount is a functional expression of the characteristic value that is determined in a dynamic manner. 3. The photographic printing exposure amount according to claim 2, wherein the difference between the minimum correction exposure amount and the maximum correction exposure amount within the group is 60% or more and 140% or less. Method. 4. A method of determining a corrected exposure amount to an exposure amount based on an average density obtained by photometrically measuring a photographic film, and correcting the exposure amount to determine a photographic printing exposure amount from a photometric value of the photographic film. Obtain characteristic values such as average density, maximum density, minimum density, etc., and classify whether the corrected exposure amount for the exposure amount based on the average density is at least reduced, unnecessary, increased, or greatly increased. Then
Prepare a plurality of modified exposure amount calculation formulas for obtaining the modified exposure amount using the characteristic value for each classification in advance, and perform photometry of the film to be burned and visually judge the classification of the film image to be burned. Input by input means,
One of the corrected exposure amount calculation formulas is selected with the input value as classification information, the corrected exposure amount is obtained using the characteristic value obtained from the photometric value, and the exposure amount based on the average density is corrected to print the exposure. A method for determining a photographic printing exposure amount, characterized in that the amount is determined. 5. The correction exposure amount calculation formula is statistically calculated by using characteristic values such as average density, maximum density and minimum density obtained from the photometric value for films grouped according to an appropriate correction exposure amount size. 5. The photographic printing exposure amount method according to claim 4, which is a functional expression of the characteristic value that is determined in a dynamic manner. 6. The photographic printing exposure amount according to claim 5, wherein the difference between the minimum correction exposure amount and the maximum correction exposure amount within the group is 60% or more and 140% or less. Method. 7. A characteristic value such as average density, maximum density, minimum density, etc. is obtained from the photometric value of the photographic film for the basic exposure amount based on the average density etc. determined by photometry of the photographic film, and these characteristic values are used. In the method of determining the corrected exposure amount by the corrected exposure amount calculation formula, and determining the photoprinting exposure amount by correcting the basic exposure amount, the corrected exposure amount with respect to the basic exposure amount based on the average density or the like is at least decreased, A plurality of corrected exposure amount calculation formulas for determining the corrected exposure amount by using the characteristic value for each classification are prepared in advance, and the film to be printed is measured. In addition, the classification of the film image to be printed is inputted by the input means in accordance with the visual judgment, and one of the corrected exposure amount calculation formulas is selected as the inputted value as classification information, and the characteristic value is used. Obtains a positive exposure, photographic printing exposure amount determining method characterized by and modifications to the basic exposure amount based on the average density or the like was to determine the amount of exposure. 8. The corrected exposure amount calculation formula uses characteristic values such as average density, maximum density and minimum density obtained from the photometric value for films grouped according to an appropriate corrected exposure amount size, The photographic printing exposure amount method according to claim 7, which is a statistically determined functional expression of the characteristic value. 9. The photographic printing exposure amount according to claim 8, wherein the difference between the minimum correction exposure amount and the maximum correction exposure amount within the group is 60% or more and 140% or less. Method.