JPS61198144A - Determining method for quantity of exposure for photographic printing - Google Patents

Abstract

PURPOSE:To control colors properly in the formation of color prints and to reduce a subject color area by calculating the means value of light metering data in an area on color coordinates and the mean value of light metering data outside the area, multiplying both mean values by a coefficient respectively and adding the products together, and determining the quantity of exposure on the basis of said sum. CONSTITUTION:Light metering data and area information 11 in an area 1 or 2 set in a memory, etc., are inputted to an area determining means 12 respectively to determine which area each light metering data belongs to, light metering data inside and outside the area are processed by an arithmetic 13, and the determined quantity of exposure is inputted to an exposure system 14 to perform exposure to a film negative. When the chromaticity at a light metering point is determined, an area determining means 12 determines the belonging area from the area information 11 put in a table. Then, the mean density value of each picture element in the area 1 and the mean density value of picture elements outside the area are multiplied by the coefficient respectively and added to determine the quantity of exposure on the basis of the sum.

Description

[Detailed description of the invention] (Technical field of invention) This issue 1!1 relates to a method for determining the photographic printing exposure amount.

(Technical background of the invention and its problems) On the screen of a color original picture such as a standard negative film,
LATD of three primary colors: R (red), G (green) and B (old)
It is known as an empirical rule that (total average transmitted density) is approximately constant. For this reason, in conventional photo printing equipment, the LATD of the three primary colors of the negative to be printed is added to the 'I' of the three primary color components. Prints are created by controlling the amount of light at a constant level. Therefore, e! For standard color originals, it is possible to obtain good prints with good color balance.

However, for color original images in which a specific color is strongly dominant, such control by LAT[ ] is not necessarily effective, and a defective print with an unbalanced color is likely to occur. In a color original image, the strong predominance of a specific color is mainly caused by the deviation of the color of the subject, the influence of different photographic light sources, latent image regression in a specific color-sensitive layer, and the like.

On the other hand, photo printers usually have collection levels such as lower collection and full collection.
- It is applied as an effective means of color correction to color film originals in which specific colors have a strong predominance as described above. Lower correction is a control method for the three color components in the original film, in which LATD provides a relatively low exposure for the components with relatively high density, and the color lag caused by the uneven color distribution of the subject. It is suitable as a means of color correction for. In addition, Full Collection is a control method that adjusts the exposure to make the integrated results of three colors neutral when printing original film images. It is suitable as a means of color correction for film originals with latent image regression in the layers.

For example, JP-A-52-158824, JP-A-52-1
No. 58625, Japanese Unexamined Patent Publication No. 145820/1983, etc., 3 color densities centered on R17B or a combination thereof,
Print exposure using an ellipsoid with dimensional or two-dimensional coordinates, or photometric points included in the skin color area defined by the ellipse! −: The method for finding . Also, JP-A-53-12330
The issue describes a method for reproducing predetermined colors (e.g., skin tone, sky blue, green, snow ff) on color film 2 into desired colors on color paper L. However, all of these methods involve extracting a specific object color and determining the 'w'ii = light intensity by focusing on the specific object color. There is no mention of changing the collection level and printing, etc. Also, the method described above requires extraction of a specific object color, and it is extremely difficult to accurately extract a specific object color. However, if the specific object color does not exist or is extracted incorrectly, a serious defect will occur.Furthermore, in Japanese Patent Publication No. 59-29847, a method is proposed in which a relatively strongly colored point is not used to determine the exposure value. As a condition for the points used in the 0-color correction 11- mentioned above, however, Dw=
(D+++Dc+mouth e)/3.

Mouth Nw=(DN*+DNa+mouth NO)/3.

If at least two of the following three conditions are met, it will be used for one-color correction IF. In this case, it has been reported that since color coordinates are not used, it is extremely difficult to change the determination conditions based on one hue. In addition,” Section 1 (
1) In Eq.

Colors with very small left side, i.e. yellow, magenta,
Colors centered around cyan will be selected unconditionally. Further, Example “no-Da≦088-DNcfdl,
Under the judgment condition of “0-RoG≦DNR-DNG±dl”,
Colors centered on yellow, cyan, and green will be unconditionally selected. In this way, in this example, only a very limited selection of photometric points can be made, which is insufficient for the purpose of removing color phasing component colors.

In addition, in Japanese Patent Publication No. 5B-15492, the light of each predetermined area of the screen is measured, and it is checked to see if one of the three primary colors of RBG clearly exceeds the limit, and if it does, printing exposure is Methods that are not used to determine quantities are described. To check whether one of the three primary colors is exceeded, the ratio of each color (B/G, G/R, R/B) is compared with the comparison value. In this case, hue information is lost because color coordinates are not used. In this method, points based on different light sources (e.g. fluorescent light, tungsten lamp light) and points based on film aging (magenta color) are not used for light field determination, and therefore these films are based on very little erroneous photometric point information. For example, in the case of a film shot under Dunsten lamp light, the complementary color points of the light color scheme are mainly used as printing information, and these colors are printed into a print that is close to a neutral color. It has the serious drawback of intensifying the Dungesten light color. Such cases often occur not only with different light sources, but also with low color temperature light sources such as sunsets and winter.Originally, these films mainly focus on the light source color point and the aging color point, and perform neutral gray correction. should be carried out.

In addition, in Japanese Patent Application Laid-open No. 59-220780, the chromaticity of the Δ constant point to be inspected for the best matching point is compared with the limit value, and by considering whether or not to use the measurement 1 for color copying, it is possible to avoid underexposure. A method for determining copy exposure speed is shown in which the three best aspects of identifying the main hues in negatives and the elimination of dependence on film type are the first. However, it does not mention anything about improving the major drawbacks of the above-mentioned different light source films and aging films.Furthermore, in order to compare with the limit value, it is necessary to calculate the distance of the vertex of the color vector from the center for each point. However, it also has the disadvantage that it takes a very long calculation time. Furthermore, setting the thinnest point (i.e., mask density) as the origin of color coordinates does not take into account the sensitivity balance differences and gradation differences among the red-sensitive layer, green-sensitive layer, and blue-sensitive layer, which differ depending on the film type. Since it is not possible to accurately specify colors based on chromaticity depending on the species or photographic exposure stitch, there is a drawback in that there is a limit to the identification of main hues.

(Object of the invention) This invention was made under the above circumstances,
It is an object of the present invention to appropriately control colors in the production of color prints, reduce or eliminate subject color feria, and distinguish between different light source films and color feria to determine appropriate photo printing exposure stitching. The purpose is to provide a method.

(Summary of the Invention) The present invention relates to a method for determining a photographic printing exposure value,
In addition to metering the whole or part of the original film by dividing the screen, preset color coordinates! - determine whether it is inside or outside the area, and determine whether the first f of the photometric data in the area L is determined.
The average value and the second f average value of the photometric data outside the above region are determined.

! - The exposure amount is determined based on the values obtained by multiplying the first and second uniform images by respective coefficients and adding the results. Further, in another invention, the entire surface or the part of the film original image is divided and photometered, and the L upper light data is determined to which of a plurality of divided group areas on preset color coordinates it belongs. is determined, the average value of 1-upper light data is determined for each group area, and the exposure jj is determined based on the value obtained by multiplying each of these f average values by a coefficient and adding them.

Furthermore, in another invention, a plurality of areas are set on one color coordinate, and one of the areas is selected and compared with the photometric data obtained by dividing the whole or part of the original film screen into E-records. The average value of f for the selected area is determined, and the amount of exposure is determined based on 1, which is obtained by multiplying each of the average values by a coefficient and adding the results.

(Embodiment of the invention) Figure 2 shows colors (R, B, C) that have a high probability of causing color feria.
), the color due to film discoloration (M), the light source color (tungsten light, fluorescent light), and the color that is difficult to distinguish between the light source color and the color that causes color shift (G), using the color coordinates R-G:G- B
They are shown separately at the top, showing the change in the average density before and after the photometric point is removed. That is, in FIG. 2, ◯ indicates a light source and a discolored image, and ▪ indicates an image with color phasing. Images with color feria show values very close to gray, whereas the changes in the illuminant and discoloration images are small; this has less effect on the latter images, and it is possible to remove the color feria component colors. It shows that there is.

Due to the relationship between the color coordinates RG:G-8 and the film original image, the present invention uses fluorescent lamps on the color coordinates as shown in FIG.

A region l containing a large amount of tungsten light and magenta is set, and the photometric points of the original film are calculated and processed by distinguishing between those inside and outside this region l. The area l in Fig. 3 is
This shows an example of area setting for an area where there are many film originals illuminated by fluorescent lights. Since it is difficult to distinguish between fluorescent lights, green grass, ice cream, etc., a wide area can be set for Green G. In addition, in areas where there are few original film images illuminated by fluorescent lamps, a region 2 with a relatively narrow green region is set in order to eliminate the color feria of green G, as shown in FIG.

Figure 5 shows the area l or 2 set on such color coordinates.
In contrast, the block configuration of a device that embodies this invention, which classifies the photometric data of the actual film original image and determines the exposure amount, is comprised of the photometric data from the photometric system 10 and the settings in the memory, etc. Area information 11 of bond city 1 or 2 (for example.

A region number is determined for each chromaticity point) is inputted to the region determining means 12, which determines which region each photometric point belongs to, and processes the photometric data outside and inside the region as described below. The exposure amount determined by the calculation means 13 is manually inputted to the exposure system 14 to expose the original film image.

When the chromaticity of the photometric point is determined, the region determining means 12 immediately determines the yielding region based on the tabulated region information 11. As this determination method, the method disclosed in Japanese Patent Application Laid-Open No. 57-208422 can be used. By using such a method, region determination, which conventionally took time, can be performed immediately, and furthermore, color regions can be set freely. In particular, as will be described later, a plurality of settings can be made for the color direction. This also has the advantage of allowing detailed settings and analysis regarding hue and saturation.

Next, an example of the method of this invention will be explained according to the flowchart of FIG. Here, it is assumed that an area l on color coordinates and an area outside the area l on the color coordinates as shown in FIG. 3 are set in the memory.

In this invention, first, a film original image is processed using a two-dimensional image sensor, a line sensor, etc., and a large number of images J as shown in FIG.
The screen is divided by Sn and scanned (photometered according to SL). The photometric value of each divided pixel is normalized (step S2). The first stage of normalization is described in Japanese Patent Laid-Open No. 58-103.
! A method such as No. 9 can be used. By normalizing the photometric values, the same color coordinates can be used even if the film density or film type is different, and the origin of the coordinates can be set to the color a. In this case, the photometry of each image '#Sn is RGB
Calculate which position the photometric value of each color corresponds to on the color coordinates shown in Figure 3, and use the memorized area information to determine whether it is inside area 1 or outside area 1. The determination is made (steps S3 and S4), and the calculation of the characteristic value for each pixel is repeated until all photometry is observed (step S5.';6>, that is, the number of pixels for photometry is set to n. If the number of photometric data in area l is i and the number of photometric data outside the area is j, then i
+j=n and area! The average density value Di of each pixel within the area and the average density (e'jDj) of the pixels outside the area are determined by the calculating means 13, which is a microcomputer or the like. The average density value Di of all pixels and the average density value Dj of all pixels outside area l are multiplied by coefficients Ka and Kb.
Since it is necessary to reduce the influence of pixels outside of Good, equation (2) above is a general equation for density data, and in reality it is necessary to calculate the three primary colors RGB, and the density values for these three primary colors are set to 0.
In the pixel data of FIG. 6, the hatched area indicates data inside area l, and the pixels without hatching indicate data outside area l. , then the average value i in the shaded area and the average concentration i in the other areas are
is calculated for each of the three primary color ROBs. Instead of using the out-of-area data as is, it is effective to convert it into other data (for example, the average value of the RGB 3 primary colors f average density values outside the area) and use it. When the average value is used, the accuracy of the density value is good even if the number of i is small, and the variation in print density is also reduced. The coefficients Ka and Kb in this case are not limited to the above-mentioned ranges, but for example, coefficients proportional to the number of data items are used.

Calculating means ! 3, however, no=(IL * DR + b e DG + c *
Do)/(a+b+c), or the exposure value aperture R determined by this calculation.
The exposure control means 14 performs exposure at O, DOG, and DBO.

Here, the coefficients KR, KG, KB in the above formula (3) and the coefficients [11- to 33] in the above formula (4) are color correction coefficients, and a plurality of predetermined coefficient groups are selected by visual recognition. or the function f(X
The function f(Ni, MXi), which may be determined by the collection level discriminant formula i, MXi), is the high collection level and the normal vocabulary level or lower
This is a discriminant function expression that identifies the collection level. Ni of the function f indicates the image Jl [in the area, MXi indicates the maximum density in the area, and Xi and MXi of each area are the average density of each area calculated by the characteristic value calculation unit (S5) in each area. Regarding the 0 discriminant function formula, which can be obtained at the same time as calculating
(2013). The collection and level classification may be made into major classifications based on the position in the color coordinates of the image, that is, the average density of the number of pixels per pixel (jl+), etc., and the classification may be determined using a function formula determined for each classification. It is preferable that the above-mentioned major classification includes at least one or more of a subject group including tungsten lamp light and a subject group including fluorescent lamp light. In this way, the collection method is selected (step S6
), Determine the correction coefficient of equation (3) or equation (4) in step S9), 'JA light control means 1
Exposure 7JD*o sent to 4, DGO.

Obtain OaO (step 5IO), determine the final exposure value, and then perform exposure control (step Sll,
512), and in the case shown in FIG. 4, the collection level may be fixed at an appropriate level without being changed.

By the way, in the description of L:, the area set on the color coordinates is divided into two areas, and the average density of the data measured inside and outside this area is calculated, but as shown in FIG. It is also possible to set up a grouped area of 3 measurement stations L), for example divided group areas like gl-gl8, and calculate characteristic values such as uniform density for each area.In this case, photometry After the area determining means 12 determines which of these group areas gl-g18 the data belongs to, the average density is 01 for each group area.
~16, Ml~1B, Xl-X1e, etc. are determined.

Then, 1-1B is the coefficient for each group area, and D=1・OI is 2・02+-・・・・・・ 10
K15・015 Now 16-018・・・・・・・・・(
5) The average density may be calculated for each of the three primary colors using the following formula. In this case, Kl- is 2...◆K
There is a relationship of lB = 1.0, and for an average picture, the weight of the coefficients in the area close to the uniform color of many film frames from the center of the color coordinates in Figure 7 is influenced. . These coefficients are calculated statistically (
For example, it can be determined by the least squares calculation method.

Furthermore, it is effective to classify the films into different types of light source films, aged films, and other films, and change the magnitude of each coefficient. This method performs the color correction in equations (3) and (4) above for hue and saturation on color coordinates, and can be performed more precisely and appropriately than conventional methods. Several types of coefficient groups are prepared in advance and one of them is selected. At this time, the function f(Ni
, NX1) is more effective. Furthermore, although a method using Ilj converted by equation (2) has been described, it is also effective to convert and use the average density of the high chroma region in equation (5). Next, the discrimination between fluorescent light and green will be explained using characteristic values in such grouped areas. 'in light lamp N11
, 812, Ml, 88. K5. N3 and 82 are O or close to O, similarly MXII and MX12 are large,
1lX1. NX8. NX5. NX3, 1lIX2 is O
or a small value, and the relationship fiK11. in the area of these fluorescent lamps. K12 has a large value because exposure is controlled based on the color of the light source. Also, on the green, the old 4. There are many old 5s, Nl, K8, 85. N3. N2 is not 0, but NX1
4. MXI5 is relatively small<, MXI, NX8. N
X5゜NX3, NX2 is large, Sarani N14/Ni
Ratios such as l, N15/N12 (7) can also be used. Discrimination accuracy can be further improved by using other factors such as the average density, its color, the number of shadow parts and highlights, and the color. For such greens, the coefficient K14. K15 is small (llj), and a coefficient such as 1 is large (li, which is 0 or more) means that the hue angle of fluorescent lights is generally smaller than the green of the grass, and the green of the grass is on the shadow side, The green light is on the highlight side, and the fluorescent light indicates that the number of plays is extremely small.Of course, it is possible to determine using a logical formula for these relationships, but the above relationship can be expressed using a functional formula. In other words, the discriminant for fluorescent lamps is V1=fl(Xi, NX1), and the discriminant for green lights is V2□r2(Ni, NX1).
In this case, if Vl is larger than v2, it is determined to be a fluorescent lamp film, and if v2 is less than Vl -L, it is determined to be a green film. In the same way, tungsten lamp light and yellow color ferria can be distinguished, formalin fog negatives and magenta color ferria (azalea flowers, pink clothes, china, etc.) can be distinguished, and cloudy or shady subjects and color divination can be distinguished. Feria (old sky, W49 clothes kg) can be identified. Based on these determination results, a group of coefficients determined in advance may be selected. Alternatively, each coefficient may be automatically calculated and determined based on the determination results.

Furthermore, Figure 8 shows this emission [! 11, which shows a further example of the Buddha seat e as shown in FIGS. 3, 4, and 7.
! #i of L several area types are set separately, and I) switch them off using the J switching means 20 (switched according to the signal amount).
The area determining means 12 can freely change the determination of the photometric data from the photometric system In as described above. In this way, multiple types of areas 21 to 23
are set in advance, and an arbitrary one is selected by the switching means 20 according to the operator's preference. C to 2
By adjusting the printing exposure, it becomes possible to determine the printing exposure with a higher degree of freedom.

In the above-mentioned embodiment, the area of color coordinates H is displayed with the horizontal axis as R-G and the vertical axis as G-8. In addition, in the above, we have explained an example of determining the color area for the entire screen when measuring the photometry of a film original image. Alternatively, the photometric point to be used may be determined based on the difference in degree or color from neighboring points, or the photometric point to be used may be determined based on the difference in degree or color from neighboring points, or the
:,'J! Part 11, Ma? The photometry area may be defined depending on the importance of a subject such as a landscape. This method of determining the color area is effective for fluorescent lamp photography and for identifying films containing green colors such as grass, and is effective to use depending on the purpose and type of subject. ``-'' explained the case of printing from photographic film to photographic paper, but this issue +J1
can be used for various systems from original photographs, for duplication into copying materials, and for reproduction, without losing its effectiveness.

(Effects of the Invention) As described in I., according to the present invention, it is possible to appropriately control colors in color print production and to reduce the subjuct color area. Previously, three classifications were required: high collection, normal collection, and lower collection, but high collection,
Collection classifications can be reduced or eliminated, such as Nord Collection or High Collection, Lower Collection or High Collection Only, and 31291
Even if 7 classifications are required, items with large collection changes are not required, so it is possible to minimize the influence of 8% 'N2 on the collection level. Furthermore, while it was previously difficult to properly print images in which the light source color and color phasing were mixed (red rays under fluorescent lighting, blue sunsets on the sea), this invention removes color phasing components. , such printing can also be performed properly. Conventional methods for removing color phasing component colors deteriorate the prints of different light source films or aged films, but according to this invention, the photometric point used to determine A light f can be strictly defined by hue and saturation. greatly improved by. At the same time, by analyzing photometric data in detail on color coordinates for each hue and saturation in the image, we can identify colors that are likely to cause color feria (R, B, C) and colors due to film discoloration (maze/maze). ), the light source color (Y), and the color (green) that is difficult to distinguish between the light source color and the color that causes color feria can be reliably separated. In addition, without determining the distance from the origin using one chromaticity diagram, by determining the area for the chromaticity point in advance and determining the color plane of the obtained photometric point, the j-median value of the photometric point can be quickly determined by IIf function. In addition, it is possible to set a pattern such as one free shape on the color area on the chromaticity diagram, making it possible to obtain highly accurate density values for exposure control. It is possible to improve the accuracy and stability of the density value for exposure control by partially using 0.
As a result of the above, it has become possible to solve the problem of color correction in photo printing, which has hitherto been a problem, and to produce high quality prints.

FIG. 9(A) shows the conventional LATD method.

The figure shows the method according to the present invention for each collection film. The horizontal axis shows the hue angle (0) of the color coordinate, and the vertical axis shows the uniformity of the saturation at each 0 of the screen average C degrees of many films as the distance from the origin. In the same figure (B), compared to figure (A), the t-uniform distance of the high correction film H is not so small over most of the zero, and the t-uniform distance of the lower correction film L is different from that of the normal correction film N. It can be seen that the distance is approaching the equal distance. This means that the color feria component color is successfully removed,
This indicates that the normal collection film and the lower collection film are printed at the same collection level.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the method of this invention, No. 21'
< is a diagram of color coordinates showing the principle of this inventive power U:, Figures 3 and 4 are diagrams each showing an example of setting the area of color coordinate E of this invention, and Figure 5 is an apparatus for realizing this invention. FIG. 6 is a block diagram showing an example of the device, FIG. 6 is a diagram showing how photometry is performed for film original images in this invention, FIG. 7 is a diagram showing another example of setting the color coordinate area of this invention, and FIG. The figure is a block diagram showing an apparatus for realizing another method of the present invention, FIG.
A) is a diagram showing the characteristics of conventional LATD exposure, and (B) is a diagram showing the characteristics of conventional LATD exposure.
FIG. 2 is a diagram showing the exposure characteristics of the present invention. 1.2... Area, lO... Photometric system, 11.21-2
3... Area data, 12... Determining means, 13...
Calculating means, 14... Exposure control means system, 20... #J
J Kakete pitcher's agent Yoshikata Yu Mia f Deputy 2nd Goyasu 3 Figure also 4 Entai 5 Figure also 6 Figure L n 7th rA sense 8 page'! :19 Map layer point Horo young distance Kojii 0. ot] Origin or 6 cost J [x o, ozu] ``Continued correction 1985, 57113

Claims (6)

[Claims] (1) Measure the light by dividing the whole or part of the original film screen, determine whether it is inside or outside the area on the preset color coordinates, and measure the photometry data within the area.
and a second average value of the photometric data outside the area, and the exposure amount is determined based on the value obtained by multiplying the first and second average values by respective coefficients and adding them. A method for determining photographic printing exposure, characterized by (2) The method for determining photographic printing exposure amount according to claim 1, wherein the photometric data is for three primary colors. (3) The method for determining the photographic printing exposure amount according to claim 1, wherein the area is set to include tungsten light source, fluorescent lamp light, and magenta. (4) Dividing and photometering the whole or part of the original film, determining which of the group areas divided into a plurality of groups on preset color coordinates the photometering data belongs to, and A method for determining a photographic printing exposure amount, characterized in that the average value of the photometric data is determined for each region, and the exposure amount is determined based on a value obtained by multiplying each of these average values by a coefficient and adding the resultant values. (5) A method for determining a photographic printing exposure amount according to claim 4, wherein a plurality of coefficients are provided for each group area, and can be arbitrarily selected and used. (6) Set multiple types of areas on the color coordinates, select one of them, and compare it with the photometric data obtained by dividing the whole or part of the film original image, and A method for determining a photographic printing exposure amount, characterized in that the average value is calculated, each average value is multiplied by a coefficient, and the exposure amount is determined based on the added value.