JPH0566498A - Photograhic printing exposure control method - Google Patents

Abstract

PURPOSE:To obtain a photographic printing exposure control method for stably and efficiently producing the photographic copy of constant quality, even if properties are reduced by a latent image preserving state, without previously setting exposing conditions at every kinds of photographic films and switching set exposing conditions according to the kind of the photographic film. CONSTITUTION:A first statistic on the picture information of at least, either of the image information for each color or average transmitted light quantities, of each original picture, is obtained, on an original picture group made by arranging frames on a color photographic film, a second statistic that the first statistic is weighted, is obtained, according to the attributes of each original picture discriminated with the picture information, and further, a third statistic that the second statistic is accumulated over plural frame original pictures, is obtained, so that the photographic printing exposures of each original pictures are determined, and a printing exposure is determined at high speed, regardless of the kind of the film and the attribute of the original picture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an exposure amount when processing a photographic print, and more specifically, a predetermined statistical amount based on screen information obtained from a plurality of original images formed on a photographic film. And a method for controlling the photographic printing exposure amount based on this statistical amount.

[0002]

2. Description of the Related Art In general photography, a subject's blue (B), green (G), red (R) (hereinafter simply referred to as B,
It is known as an empirical rule that the average reflectances of the three primary colors (described as G and R) are substantially constant. Therefore, in the conventional photographic printing apparatus, the LATD (average transmission density) of the entire area of the photographic original image is measured, and based on the measured average transmission density,
LAT for controlling the exposure amount in photographic printing so that the exposure amount given to each of the B, G, and R photosensitive layers of photographic paper becomes a constant value
The D method is used to create a photographic print with good color balance.

The LATD method has a drawback in that it is difficult to obtain a proper photographic print when an original image having an uneven luminance distribution or color distribution on an object is targeted. Such photographic originals are called subject ferria, and those caused by the uneven brightness distribution of the subject are called density ferria,
In addition, the cause of the uneven color distribution is called color ferria.

As a publicly known technique for automatically adjusting the exposure amount for the density ferria, Japanese Patent Publication No. 56-269.
No. 1 can be mentioned. That is, the original image on the photographic film is scanned, the characteristic value is obtained for each area of the image from the image density obtained by this scanning, and the classification is performed based on this characteristic value. The function adjusts the exposure amount for the original image.

Further, as a known technique for adjusting the exposure amount for color ferria, for example, CJ Bartle
Son and RW Huboi "Exposure Determination Met
hodsfor Color Printing: The concept of Optimum Corr
ection Level ", J.SMPTE, 65, 205-215 (1956). In this paper: ・ LATD for the original picture of a standard subject.
It is effective to adjust the exposure according to the above, and to make the exposure amount given to each color photosensitive layer of photographic paper a constant value. ・ For subject ferria, regardless of LATD,
It is described that no-collection in which exposure is performed with a constant light flux or exposure time is effective.

As a more practical compromise, it is said that the intermediate control method of both sides, that is, the lowward collection, is appropriate, and the optimum collection level should be selected from the overall quality of the photographic print. From such a technical background, in recent years, a photo printing apparatus is generally equipped with a selectable collection level of several stages.

In addition, E. Goll, D. Hill and W. Severin
By "Modern Exposure Determination for Custumizing P
hotofinishing Printer Response ", JAPE, 5,93-104 (197
In (9), the influence of the color temperature of the photographic lighting is remarkable for a specific hue in the chromaticity calculated based on the density of the original picture, so the exposure level control that adjusts the collection level depending on the hue. The method is shown. In this case, it is described that in order to obtain a photographic print with an appropriate color balance, it is necessary to adjust the density which is the standard for the lowward collection.

Usually, in the LATD control type photographic printing apparatus, whether the density change of each color of B, G and R of the original photographic image is due to the tone reproduction characteristics of the photographic film or the color distribution of the subject. Cannot be identified automatically. For this reason, conventionally, the exposure conditions such as the density, which is the standard for the low-ward collection as described above, are set in advance for each type of photographic film, and the setting conditions are switched according to the type of photographic film to be printed. There is.

However, with the recent increase in the types of photographic films, the setting and switching operations of the exposure conditions as described above have become complicated, which is a major factor that hinders the rationalization of the photographic printing process. Furthermore, even with the same type of photographic film, there are many cases where a photographic print with an appropriate color balance cannot be obtained under the set exposure conditions due to characteristic deterioration due to the state of latent image storage, and a photographic print of constant quality. Is a major obstacle to stable and efficient production.

As described above, in order to properly control the exposure amount in photographic printing, it is necessary to determine the density, which is a reference for color correction, based on the characteristics of each photographic film.
To solve this problem, for example, in Japanese Patent Application Laid-Open No. 55-46741, a photographic film is color-separated into three primary colors, and the obtained image densities of the respective colors are used to determine the density difference between two sets of two colors and the neutral density. It has been proposed to obtain the value of ## EQU1 ## and derive a value specific to the photographic film from the functional relationship between the two sets of density difference and neutral density and relate it to the exposure control.

As an improvement to this case, in JP-A-59-220760, the saturation is inspected for each pixel, and a special processing is applied to the pixel identified as having high saturation in the image. Is proposed.

[0012]

However, in the above-mentioned conventional technique, when most of the original images on the photographic film to be processed are original images in which the specific color of the subject is dominant, that is, color ferria, this specific color is used. Since a value specific to a photographic film is derived from the density corresponding to, there is a drawback that a photographic print with an appropriate color balance cannot be obtained.

Further, in the improvement example of the prior art, it is necessary to inspect the saturation for each pixel. If it is identified that the saturation is high, it is necessary to perform a special process for each pixel. However, there is a problem that a large amount of time is required for a series of processes. In general, an image sensor used for scanning for obtaining image information has a narrow photometric dynamic range, and it is difficult to measure the density of a photographic original image having a wide density range accurately and stably. It has drawbacks. Therefore, it is not possible to expect high reproducibility in the measured value for each pixel, and there is a problem that the above-described saturation inspection result for each pixel tends to vary.

On the other hand, in order to construct an image pickup system having a wide dynamic range, it is necessary to arrange the photoelectric conversion elements having a wide light receiving area in a linear or planar shape, which is extremely expensive. Further, since the shape of the image pickup element becomes large, there is a problem that the imaging optical system and the image pickup system including the color separation means must be increased in size. Furthermore, there is a drawback in that signal processing for switching the outputs of a plurality of light receiving elements at high speed and with a high S / N ratio is required, and the circuit configuration is inevitably complicated and expensive.

In addition, since a special process is performed on each pixel which is identified as having high saturation, a large amount of time is required for the process. Therefore, the above method is not practically desirable in terms of performance, processing time, and cost. The present invention has been made in view of the above problems, and sets the exposure conditions in advance for each type of photographic film, or switches the set exposure conditions according to the type of film, and the latent image storage state. It is an object of the present invention to provide a photographic printing exposure amount control method capable of stably and efficiently producing a photographic print of a constant quality even with respect to deterioration of characteristics caused by the above.

Further, even when most of the original images on the photographic film are color ferrias obtained by photographing a subject in which a specific color is dominant, the density which is a reference for color correction can be obtained with high accuracy, and a constant quality can be obtained. It is an object of the present invention to provide a photographic printing exposure amount control method capable of stably and efficiently producing photographic prints of 1. Another object of the present invention is to provide a photographic printing exposure amount control method capable of determining the exposure amount for a photographic original image with high reproducibility even when scanning the photographic original image with a simple and inexpensive imaging system.

[0017]

In order to achieve the above object, the photographic printing exposure amount control method of the present invention is applied to a group of original images arranged on a color photographic film, and image information of each original image is classified by color. Alternatively, the first statistic regarding at least one screen information of the average transmitted light amount is obtained, and the second statistic obtained by weighting the first statistic is obtained according to the attribute of each original image determined by the screen information. Further, by determining the third statistic by accumulating the second statistic over the originals of a plurality of frames, the photoprinting exposure amount of each original is determined, and the film type and the attribute of the original are processed for each pixel. Judge without
This is to enable an appropriate printing exposure amount to be determined at high speed.

In the weighting process, a real value in the range of 0 to 1 is multiplied so that the attribute of the original image that changes in multiple stages can be applied. Further, the weighting process is a binarization process in which 0 or 1 is multiplied to simplify the process. Further, the original image group is made up of original images in the same film, and the attribute determination accuracy of the original images is improved by accumulating information relating to the tone reproduction characteristics of the product type.

Further, the original image group extends over a plurality of photographic films, and the attribute determination accuracy of the original image is further improved. Also, the plurality of photographic films,
It is assumed that the photographic film belongs to a specific product type, and by accumulating information related to the product type, an appropriate color correction value can be obtained according to the tone reproduction characteristics of the photographic film.

Further, it is assumed that the specific product belongs to a group classified according to its characteristics, and by accumulating information related to the product in the group, an appropriate color according to the tone reproduction characteristics of the photographic film. The correction value can be obtained. Further, the product type is identified by reading the barcode attached to the photographic film so that the processing can be surely performed.

[0021]

The image density information for each color is detected by the scanning unit and the average transmission density is detected by the exposure unit. Based on these screen information, the first statistic such as the frequency distribution is obtained for each original image and accumulated. The density function and its inverse function, the correlation coefficient between each color, etc. are obtained, and the dominance of a specific color is evaluated. Then, according to the evaluation result, the first statistic consisting of screen information of each frame is weighted, and the third statistic considering the product type of the film is obtained, and the color for the printing exposure amount set by the LATD method is obtained. Correction is made to determine the final exposure amount.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for controlling the exposure amount for photographic printing of the present invention will be described below with reference to the drawings. FIG. 1 is a structural example of a 135 photographic film which has been subjected to development processing, FIG. 2 is an overall structural view of a photographic printing apparatus, FIG. 3 is an explanatory view showing the internal structure of a scanning section in detail, and FIG. 4 is an image processing section. Detailed configuration diagram, Figure 5
Is an explanatory diagram showing an example of rounding processing of image information, FIG. 6 is a principle diagram showing rounding processing of secondary line image density information, FIG. 7 is a detailed configuration diagram of an information processing unit, and FIG. 9A is a flowchart showing the processing, FIG. 9A is a cumulative density function (weighting α is 1) obtained from a photographic film of a general subject in which all the original images have no uneven color distribution, and FIG. 9B is Cumulative density function obtained from a photographic film in which half of the original images are green grass (color ferria), FIG. 10 shows an example of frequency distribution, FIG. 11 shows an example of cumulative density function, and FIG. 12 shows an example of LUT. Is. (Device Configuration) In FIG. 1, a photographic film F having a developed original image (group) I is spliced by a splice portion 10 to form a roll. In the roll-shaped film F, a notch (group) 12 indicating the center position of the original image is arranged at the side edge portion of each original image I in the notch step before the photographic printing step. Transport control such as positioning of the photographic film F in the subsequent steps is performed by detecting the notch 12.

As shown in the figure, the photographic film F has a bar code 14 indicating the film type on the side edge thereof. Note that the photographic film F may be another photographic film (for example, 110) regardless of the 135 photographic film. P is a perforation (group) arranged on the side edge of the film F.

The roll-shaped photographic film F thus treated is printed in the photographic printing apparatus 100. 2, the photographic film F is set on a spool 20 and wound on a spool 21 via a predetermined transport path. A scanning unit 22 is provided in the middle of the path, and the original image I recorded on the photographic film F by the scanning unit 22 is recorded.
Is color-separated into B, G, and R colors. The scanning unit 2
The image signals of B, G, and R colors obtained in 2 are sent to the image processing unit 24, A / D-converted and shaped into image density information of a predetermined format, and then sent to the information processing unit 26. Is configured.

The image density information is stored in the information processing section 26.
In this case, the processing as described below is performed, the correction amount for each original image is calculated from the result, and the signal of the correction amount is transmitted to the exposure control unit 30 through the communication line 28. The photographic film F that has passed through the scanning unit 22 absorbs a difference in transport speed between the photographic film F and the photographic film F between the scanning unit 22 and the exposure unit 32, and pre-scans a plurality of original images before exposure. Through the exposure unit 32. The transport path between the scanning unit 22 and the exposure unit 32 is a maximum of one photographic film (24 sheets are taken.
The length is equivalent to 35 film equivalents), whereby the image density information corresponding to almost all original images I recorded on one film can be obtained prior to exposure.

Each original image I formed on the photographic film F is
The light positioned by the exposure unit 32 and emitted from the light source 36 is illuminated by the diffusion unit 38 as uniformized light. Further, the transmitted light of the original image I is optically focused by the lens 54 and is exposed on the photographic printing paper 40. At this time, the average transmitted light of B, G, and R colors of the original image I is the photometric filters 42a and 42b of B, G, and R colors.
42c through photodiodes 44a, 44b, 4
It is received by 4c. The B, G, and R photometric signals obtained by photoelectrically converting the received light amount are supplied to the exposure control unit 30 and then A / D converted, and the resulting data and the correction amount supplied from the information processing unit 26. The exposure amount is calculated on the basis of and.

The exposure amount obtained here is used as the exposure control unit 30.
Of the yellow (Y), magenta (M), and cyan (C) subtractive cut filters 50 a, 50 b, and 50 c disposed above the exposure unit 32, and the shutter 52 disposed below the exposure unit 32. Converted to operating time.
Then, according to this operating time, the cut filter 50a,
50b, 50c and the shutter 52 are inserted in the exposure optical path so that the exposure amount applied to the photosensitive layers of the respective colors of the photographic printing paper 40 can be adjusted.

After the completion of this exposure, the photographic printing paper 40 is transported by a predetermined distance in preparation for the next exposure, and the photographic film F is transported to position the original image I to be printed next in the exposure section 32. .. In this way, the original image I formed on the photographic film F is sequentially subjected to printing processing. In the internal configuration diagram of the scanning unit in FIG.
In the scanning unit 22, first, the light emitted from the light source 59 is formed into substantially parallel light by the lens 60. The parallel light passes through the color separation filters 62a, 62b, 62c arranged in parallel along the transport direction of the photographic film F to be separated into B, G, R colors.

The illumination light color-separated into B, G, and R colors in this way passes through the slit 64 and is illuminated on the photographic film F. The light transmitted through the photographic film F is B,
CCD arranged at a position corresponding to the illumination light of each of G and R
Photoelectric conversion is performed by the line sensors 68a, 68b, 68c. Here, the CCD line sensors 68a, 68b,
Each of the 68c has 2048 pixels, and uses a one-dimensional image pickup device capable of scanning over the length of 32 mm in the width direction of the photographic film F.

By these, 3 in the width direction of the photographic film F is obtained.
Main scan was performed for 2 mm, and B, G, R obtained
The image signal of each color is supplied to the image processing unit 24. Also,
Notch 12 and splice part 1 attached to photographic film F
0 and bar code 14 correspond to detectors 70a and 70, respectively.
b, 70c, and the detection signal is supplied to the conveyance control circuit 72. The conveyance control circuit 72 processes the detection signal into a notch signal, a splice signal, and a bar code signal, sends the signal to the image processing unit 24 and the information processing unit 26 via the system bus 74, and the pulse motor 75. To control the conveyance of the photographic film F.
Further, the carrier pulse at this time is supplied to the image processing unit 24 as a synchronization signal at the time of sampling the image signal.

The photographic film F is a pulse motor 75.
Thus, the sheet is conveyed at a conveying speed of 0.25 mm / pulse, and the sub-scanning is performed accordingly. In the detailed configuration diagram of the image processing unit in FIG. 4, the image processing unit 24 performs the following signal processing.

The image signal supplied from the scanning unit 22 is amplified by the amplifier circuit 80, sampled by the sample hold circuit 82, and converted into a digital signal by the A / D converter 84. Here, the timing control circuit 86 causes the scanning unit 22 to have the CCD line sensor 68a
A drive signal for driving 68b and 68c is sent, and the sampling timing is controlled. At this time, the sampling number is 128 times for one scan, and the A / D conversion is processed by 16 bits. The digitized image signal is an LUT composed of a ROM or the like.
It is converted into a density value via a (lookup table) 88 and stored in the image buffer 90.

The conversion table shown in the following equation (1) is stored in the LUT 88. Y = a * log (X + b) (1) where X is an input to the LUT 88 and Y is its output. Further, a is a constant relating to conversion into a printing density (scanning unit 2
2 is determined by the photometric density determined by the spectral characteristics of the imaging system and the spectral sensitivity of photographic printing paper), and b is a constant for removing the influence of dark current during imaging.

The LUT 88 is provided with a plurality of conversion tables obtained by substituting several kinds of numerical values into the constants a and b of the equation (1), and is selected by the CPU 92 as appropriate. The conversion table selected here does not necessarily have to be the same for each color of B, G, and R, and may be different. In this way, the 16-bit line image density information consisting of 128 pixels is stored in the image buffer 90. Hereinafter, this is referred to as primary line image density information Da. (Rounding Processing) Next, the internal processing (image processing) in the image processing unit 24 will be described.

The CPU 92 retrieves the primary line image density information Da in synchronization with the carrier pulse, performs the following rounding processing, and then performs image processing in the main scanning direction stored in the memory 94 for each scanning line. Here, there is a problem that the effective image area in the main scanning direction (first line image density information Da) differs depending on the format of the photographic film F. Therefore, in accordance with the format of the photographic film F, an image area in the main scanning direction for rounding (image simplification) and the number of pixels are set in advance, and the CPU 92
Each pixel of the set image area is rounded up to the set number of pixels.

After processing to the line image density information of a predetermined number of pixels in this way, it is stored in the memory 94 for each scanning line. .. Here, the target number of pixels by rounding is 16 pixels. In the explanatory view showing an example of the rounding processing of FIG. 5, in the primary line image density information Da obtained from the 135 photographic film, an image area having a length of 20 mm is set as an effective area near the center and A value of 5 obtained by dividing the corresponding 80 pixels by the target number of pixels 16 is set as the number of rounded pixels.

In the case of 110 photographic film, this 1
In the primary line image density information Da obtained from 10 photographic films, the image area corresponding to the width of the central portion 12 mm is set as the effective area, and the pixel number 48 corresponding to this length is set as the target pixel number 16. The value obtained by dividing 3 is set as the number of rounded pixels. Here, the rounding processing is to take the arithmetic mean of the density information of each pixel, but this processing is
This has an effect of reducing the influence of noise included in the image signal.

However, the rounding processing does not need to target all the pixels in the selected image area, and the method of taking the upper arithmetic mean with appropriate thinning out or taking the arithmetic mean is not used. A method of only thinning out a predetermined number of pixels may be used. In this case, although there is no noise reduction effect, an improvement in processing speed can be expected. By the rounded image processing in the main scanning direction as described above, the secondary line image density information Db of a predetermined number of pixels (16 pixels in this case) is obtained regardless of the format of the photographic film F, and the secondary line image is obtained. The density information Db is stored in the memory 94 as line image density information corresponding to many scanning lines as the photographic film F is conveyed.

Further, the CPU 92 takes out the secondary line image density information Db stored in the memory 94, shapes it into two-dimensional image density information of a predetermined format by the next image processing in the sub-scanning direction, and outputs the information. It is sent to the processing unit 26. Here, the original image formed on the photographic film F and the secondary line image density information Db stored in the memory 94.
The management of the correspondence relationship with and becomes a problem, but this management is performed by the notch signal. That is, as described above, the notch 12 previously provided at the central position of the original image I is detected by the scanning unit 22, and the notch signal is transmitted to the CP via the system bus 74.
It is sent to U92. Therefore, when the CPU 92 receives the notch signal, it starts counting carrier pulses, and when the predetermined count value is reached, the primary line image density information Da stored in the image buffer 90 is taken out and the predetermined scan line is read. The above-described image rounding processing in the main scanning direction is repeated up to the number.

As a result, the address of the secondary line image density information Db stored in the memory 94 is stored in a predetermined area of the memory 94 corresponding to the notch signal. In this way, the secondary line image density information Db is managed in correspondence with the position of the original image formed on the photographic film F.
However, the above correspondence is CC for each color of B, G, and R.
This is related to the arrangement of the D line sensors 68a, 68b, 68c.

Therefore, the predetermined count value is set by selecting a constant stored in advance for each color. This selection can be performed by a switch (not shown) provided inside the image processing unit 24. As a result, the image processing unit 24 can have a common configuration for each of B, G, and R colors, and the internal processing can also be shared. Also, by operating these processes in parallel, an extremely high processing speed can be achieved.

Here, the effective image area in the sub-scanning direction (the number of scanning lines) may differ depending on the format of the photographic film F. 1 for every 0.25 mm in the scanning unit 22
Although scanning is performed once, for example, the number of scanning lines corresponding to the processing target area 32 mm of the full size original image of 135 photographic film is 128, but the number of scanning lines corresponding to the processing target area 16 mm of the half size original image. Is 64.

Therefore, the CPU 92 sets the number of scanning lines stored in advance according to the format of the photographic film F as the predetermined number of scanning lines. Further, rounding processing is performed in the sub-scanning direction in accordance with the set number of scanning lines to process the two-dimensional image density information including a predetermined number of pixels in the sub-scanning direction. here,
The number of pixels in the predetermined sub-scanning direction is 16.

In the principle diagram showing the rounding processing of the secondary line image density information of FIG. 6, the scanning line number 128 is set to a predetermined sub-value for the secondary line image density information Db obtained from the full size original image. The number 8 divided by the number of scanning pixels 16 is
It is set as the number of rounding scan lines. Further, with respect to the secondary line image density information Db obtained from the half size original image, the number 4 obtained by dividing the number of scanning lines 64 by the predetermined number of sub-scanning pixels 16 is set as the number of rounding scanning lines.

Here, the rounding process is to take the arithmetic mean of the image density information in the sub-scanning direction, but this reduces the influence of noise contained in the image signal as in the image processing in the main scanning direction. Is effective. However, the rounding does not necessarily need to target all the stored secondary line image density information Db, and a method of taking an upper arithmetic average that is appropriately thinned, or thinning by a predetermined number of scanning lines is performed. A method that does not take the arithmetic mean only by itself is also effective in improving the calculation speed.

The image processing in the main scanning direction need not be performed in response to all the carrier pulses, but may be performed intermittently. As a result, not only the image processing in the main scanning direction but also the image processing in the sub scanning direction is lightened, so that the processing speed can be greatly improved. In this case, the intermittent processing cycle may be changed according to the format of the photographic film F. (Structure of Information Processing Unit) By the image processing in the sub-scanning direction as described above, the two-dimensional image density information of a predetermined number of pixels, here 16 × 16 pixels, is finally obtained regardless of the format of the photographic film F. The information obtained is sent to the information processing section 26. Therefore, the information processing unit 26 can perform common processing regardless of the format of the photographic film F.

In the detailed configuration diagram of the information processing unit of FIG. 7, the two-dimensional image density information of each color of B, G and R sent from the image processing unit 24 is stored in the memory 102 via the system bus 74. To be done. The CPU 104 uses the memory 10
The two-dimensional image density information stored in 2 is read out, and the correction amount for each original image I formed on the photographic film F is calculated.

This correction amount is transmitted to the exposure controller 30 through the communication line 28. Further, notch signals, splice signals, and bar code signals sent from the carriage control circuit 72 of the scanning unit via the system bus 74 are also stored in the memory 102 and processed by the CPU 104. The auxiliary storage unit 106 stores information to be saved, constants necessary for processing, and the like. The auxiliary storage unit 106 is composed of, for example, a magnetic disk, and the recorded information can be taken out as needed. With this, not only can information be stored for a long period of time, but it can be saved even when the power is cut off, and the information saved by an external independent device can be processed and constants can be initialized and changed. ..

Further, 108 is a keyboard for various operations, 112 is a display, and the interface circuit 110
I / O can be done via. (Software of Information Processing Unit) Next, internal processing in the information processing unit 26 will be described. Information processing unit 2 in FIG.
In the flowchart showing the process of No. 6, first, a variable L indicating the number of original images processed in step 1 (S1) is initialized.

Next, in step 2 (S2), two-dimensional image density information (hereinafter referred to as image density information) regarding each color of B, G, and R is fetched from the memory 102, and the variable X _K
Set to (i, j). Here, i is a pixel position in the main scanning direction, j is a pixel position in the sub scanning direction, and K is each color of B, G, and R. In step 3 (S3), the average value AVE _KL of the image density information for each of B, G, and R colors is calculated. This value is used for calculating the color correction amount described later.

In step 4 (S4), the first statistic of the image density information on each of B, G, and R colors, that is, the frequency distribution F.
RQ _KL (S) is calculated. Here, S represents the image density, and K represents each of B, G, and R colors. Steps 5 to 9 (S5 to S
In 9), the attribute of the original image is determined using the cumulative density function.

In step 10 (S10), 1 is added to the variable L indicating the number of processed original images to prepare for the processing of the next original image. In step 11 (S11), it is determined whether or not this L is larger than a predetermined original image number N. If it is larger (Yes in the figure), step 13 (S13) is executed, and if it is not larger (No in the figure) step 12 (S1).
The process 2) is executed. Here, the predetermined original image number N is a predetermined constant, and this constant is related to the transport path between the scanning unit 22 and the exposure unit 32 of FIG. 2 described above. In this example, the maximum transport route is 24
The length is equivalent to that of a single-shot 135 photographic film. For example, if the predetermined number of original images N is 24, an image corresponding to almost all original images recorded on one 24-shot 135 photographic film. From the density information, the cumulative density function can be obtained prior to printing exposure.

Further, even when the number of original images is large, as in the case of a 36-photographed 135 photographic film, for example, the above-mentioned accumulation is obtained from the image density information corresponding to a sufficient number for obtaining the statistical amount, for example, 24 original images. It is also possible to determine the density function prior to exposure. In step 12 (S12), it is identified whether or not the processed original image is the last original image formed on one photographic film, and if it is the last original image (Yes in the drawing), the next step 13 (S13) is performed. ) Is executed, and when it is not the last original image (No in the figure), the processes from step 2 onward are executed again.

In the information processing unit 26, the splice signal sent from the transport control circuit 72 of the scanning unit 22 via the system bus 74 is stored in the memory 102, and C
It is designed to be processed by the PU 104, and by referring to this signal, it is possible to identify whether or not it is the last original image recorded on one photographic film. As a result, even if the number of original images is small, such as 12-shot 135 photographic film,
From the image density information (screen information) corresponding to all the original images formed on the book, the above cumulative density function can be obtained prior to the exposure.

As described above, the first statistic relating to the image density information, the frequency distribution FRQ _KL (S), is obtained from the individual original images recorded on the photographic film. In the following step 13 (S13), the cumulative density function CDF _K of the image density information for each of the B, G, and R colors of the plurality of original images recorded on the photographic film is calculated from the frequency distribution of the image density information corresponding to each of the above original images. (s) is calculated by the following equation (2) for all s. Where α _t is the frequency distribution FRQ obtained from the t-th original image
Is a weighting coefficient that is assigned to, and takes a numerical value in the range of 0 to 1. The first statistic, FRQ _Kt (s), is weighted and corrected by this coefficient α _t , and as a result, the second statistic, α _t × F as shown on the right side of the equation (2).
RQ _Kt (s) is required. Furthermore, by executing the summation of the equation (2), the third statistic / cumulative density function CDF
_K (s) is required.

In this way, the cumulative density function CDF _K (s) which is the third statistic is obtained from the screen information of a plurality of original images recorded on one photographic film. _K (s) has a close correlation with the tone reproduction characteristics of photographic film, and the image density of each color that gives this cumulative density function a predetermined value is extremely estimated as the neutral color recorded on this photographic film. It has been confirmed by experiments that it is effective.

Therefore, in the present embodiment, the image density of each color that gives a predetermined value to this cumulative density function is used as a reference for color correction in determining the photographic printing exposure amount. (Method of Determining Color Correction Criterion) FIG. 9A is a cumulative density function (weighting α is 1) obtained from a photographic film of a general subject in which all original images have no uneven color distribution. .. FIG. 9B is a cumulative density function (weighting α is 1) obtained from a photographic film in which half of the original images are green grass (color ferria). In FIG. 9, the horizontal axis represents the image density and the vertical axis represents the cumulative density function.

From these FIG. 9, among the image densities that give a predetermined value to the cumulative density function (FIG. 9b) obtained from the photographic film obtained by photographing half of the original image with green grass as a subject,
The G concentration becomes relatively high (shifted to the right in the figure). In other words, if many of the original images on the target photographic film are color ferrias obtained by shooting a subject with a distribution that is biased to a specific color, the cumulative density function obtained from multiple original images is not always unique to the photographic film. A neutral color cannot be estimated.

This problem is solved, for example, by setting the weighting factor α _t of the above-mentioned equation (2) to 0 and excluding it from the accumulation target for the color feria where the specific color of the subject is dominant. be able to. By this processing, the third statistic is obtained only from the original image obtained by photographing a normal subject with low saturation, and the neutral color recorded on this photographic film can be estimated with higher accuracy. it can. As a result, it is possible to accurately obtain the color correction reference in determining the photographic printing exposure amount.

In the above description, an example of binary logical processing of whether the original image is a color ferria or a general subject is shown. However, the deviation of color distribution and the saturation are extremely low. It may be possible to perform multivalued logical processing in consideration of the fact that there are many stages up to the highest. In this case, for example, a numerical value in the range of 0 to 1 is appropriately assigned to α _t in equation (2). The numerical values for weighting are not necessarily standardized values as in this example, and may be in the range of 0 to 256, for example.

Here, the above-mentioned weighting processing is uniformly performed on the statistical amount of the image density information, and does not require the processing for each pixel as in the prior art.
Therefore, the processing can be performed easily and at high speed, and at the same time, the result can be obtained with high reproducibility and stability. (Determination Method of Weighting Coefficient α) Next, the determination method of the weighting coefficient α will be described in detail.

FIG. 10 shows an example of the frequency distribution obtained in step 4. In the figure, the horizontal axis represents the image density S and the vertical axis represents the frequency FRQ. The frequency distribution thus obtained has a unimodal distribution in the case of an image of a general subject, regardless of the color temperature of the photographing illumination and the type of photographic film (FIG. 10a). In the case of a color ferria where a specific color (for example, G) is dominant in the subject, the appearance ratio of the density for that color (for example, G) is roughly divided into a high density side and a low density side, and thus a bimodal distribution is obtained. And is monomodal for other colors (eg, B, R) (FIG. 10b). Therefore, by analyzing the frequency distribution of the image density information of each of B, G, and R colors, it is possible to determine the attribute of the original image, that is, whether or not it is a color ferria. An example of the analysis method will be described below according to the flowchart of FIG. 8 described above.

In step 5, the cumulative density function CDF _k (S) of the image density information for each color of B, G and R of this original image is obtained from the above frequency distribution by the following equation (3). FIG. 11 shows an example of the cumulative density function thus obtained. The horizontal axis of the figure is the image density s, and the vertical axis is its cumulative density function CDF. Here, the maximum value of the cumulative density function CDF is 256 pixels (16 × 16 pixels) of the image density information.
Is. This cumulative density function is B, G, R in the image (FIG. 11a) obtained by photographing the general subject corresponding to FIG. 10a.
Each color shows almost the same tendency. On the other hand, in the image of the color ferria in which the specific color (for example, G) is dominant in the subject corresponding to FIG. 10b, the specific color (for example, G) shows a unique tendency. Such a tendency, that is, the dominance of a specific color in a subject can be quantitatively evaluated by obtaining the correlation between the respective colors with respect to the inverse function of the cumulative density function of each of B, G, and R colors. Further, as is clear from the equation (3) and FIG. 11, since this function is a continuous and monotonically increasing function with respect to an arbitrary s, its inverse function can be easily obtained.

In step 6, the inverse function is calculated from the cumulative density function of the above-mentioned image density information, and in step 13, the inverse function value is calculated from the cumulative density function for each color of B, G and R corresponding to each original image. S _k (Y) is calculated by the following equation (4). S _k (Y) = CDF ^-1 _k (Y) (k = B, G, R) (4) Here, Y is a plurality of predetermined cumulative density function values. The function value Y may be any value that does not exceed the minimum value 1 to the maximum value 256 (the number of pixels of image density information), but in order to reduce the subsequent processing, for example, a multiple of 8,
Values such as 8, 16, 24, ..., 248 may be taken.

In step 7, from the sequence of inverse function values of the cumulative density functions of B, G, and R colors thus obtained,
The correlation coefficient between each color is derived by the following equation (5). CC _BG = Cov (Y _B , Y _G ) / {Var (Y _B ) × Var (Y _G )} ^1/2 CC _GR = Cov (Y _G , Y _R ) / {Var (Y _G ) × Var (Y _R )} ^1/2 CC _RB = Cov (Y _R , Y _B ) / {Var (Y _R ) × Var (Y _B )} ^1/2 (5) where CC _BG , CC _GR , CC _RB is the correlation coefficient between each color of BG, GR, and RB in the column of the inverse function value of the cumulative density function, Cov is the covariance, and Var is the variance. This correlation coefficient reflects the difference in shape among the B, G, and R colors of the cumulative density function.

That is, for example, in the case of an image of a general subject photographed corresponding to FIG. 11A, the three correlation coefficients show almost the same value. However, in the case of a color ferria where a specific color (for example, G) is dominant in the subject corresponding to FIG. 11b, the correlation coefficient CC between the specific color (for example, G) and another color
_BG and CC _GR show extremely small values as compared with other correlation coefficients CC _RB . Therefore, for example, the minimum value of these three correlation coefficients may be adopted as the evaluation amount CD of the dominance of the specific color in the subject. When all three correlation coefficients have extremely small values, a method of adopting the difference between the maximum value and the minimum value as the evaluation amount CD can be considered. Here we follow the latter example.

That is, in step 8, the evaluation amount CD of the dominance of the specific color as described above is obtained by the following equation (6). CD = Max (CC _BG , CC _GR , CC _RB ) -Min (CC _BG , CC _GR , CC _RB ) (6) In step 9, the image density information of each of B, G, and R colors as described above is displayed. The attribute of the original image is determined based on the analysis.

Here, the attribute of the original image, that is, whether or not the subject has a color distribution bias is determined by the third statistic,
That is, it may be replaced with the determination as to whether or not to add the frequency distribution that is the first statistic to the cumulative density function of the image density information of a plurality of original images. This means that if the CD value exceeds a predetermined value, it is a color ferria, so it is excluded from the addition.
If the value of CD is less than or equal to a predetermined value, it is an original image of a standard subject, and the weighting coefficient α
Corresponds to the binary determination of the corresponding values, that is, 0 and 1. However, according to this method, when the CD is in the vicinity of the above-mentioned predetermined value, the situation in which it is discriminated as either 0 or 1 is caused, and variations are likely to occur. Therefore, the attribute of the color photograph original image to be discriminated may be multivalued. This is because the weighting coefficient α is 1 for CD.
It corresponds to the determination according to a function of several orders including the following, or a look-up table (LUT) capable of performing non-linear conversion. Here we follow the latter example. α = LUT (CD) (7) FIG. 13 shows an example of this LUT. In the figure, the horizontal axis is the evaluation amount CD of the dominance of the specific color, and the vertical axis is the collection level CL. Here, the value of α takes a value in the range of 0 to 1, but when it is 0, the maximum correction is added to the frequency distribution (full correction), and when it is 1, no correction is made (no correction). This is as described above.

Although α is determined from one type of evaluation amount with respect to the dominance of a specific color here, CL may be determined from more types of evaluation amount. In this case, the evaluation amount is B in a standard image or a large number of images,
Standard chromaticity (x ₀ , y ₀ ) obtained from the average value of the image density information of each of G and R, and chromaticity (x, x obtained from the average value of the image density information of each of B, G, and R colors of the image. What is obtained from the comparison of y) is given as an example. Chromaticity (x, y)
Is given, for example, by the following equation (8). ^{_{x = AVE B × 3 1/2 /}} 2 - AVE R × 3 1/2 / 2 y = AVE B / 2 - AVE G + AVE R / 2 ··· (8) where, AVE _B, AVE _G, AVE _R is B, G, R
The average value of the image density information of each color is shown. Further, as the evaluation amount regarding the dominance of the specific color based on the chromaticity, the saturation SAT and the hue HUE shown in the following expression (9) can be cited. _{SAT = {(x-x 0} ) 2 + (y-y 0) 2} 1/2 HUE = Tan -1 {(y-y 0) / (x-x 0)} ··· (9) above As described above, since the evaluation of the dominance of the specific color in the subject is based on the statistical amount of the image density information, high accuracy is not necessarily required for each pixel. Therefore, an inexpensive element typified by a CCD image sensor can be used for the image pickup system for scanning the original image, and the signal processing system can also have a simple circuit configuration.

The coefficient α related to the correction of the first statistic is determined from the evaluation amounts relating to the dominance of the plurality of specific colors thus obtained. This determination complies with the following equation (10). α = f (P ₁ , P ₂ , P ₃ , ...) (10) where P _i (i = 1,2,3, ..., N) is the control of a plurality of specific colors. An evaluation amount regarding sex, f is a function. The function g may be a linear or non-linear mapping from the N-dimensional space to the one-dimensional space, or may be a logical expression.

As described above, the method of using the evaluation amount relating to the dominance of a plurality of specific colors when determining the weighting coefficient α is effective in improving the reliability and accuracy of the collection level CL. (Color Correction) Next, the calculation of the color correction amount will be described.

The cumulative density function obtained from the image density information corresponding to a plurality of original images recorded on the photographic film as described above is a statistical amount according to the tone reproduction characteristic of the photographic film. Therefore, the neutral color recorded on this photographic film can be estimated from the image density of each color that gives a predetermined value to this cumulative density function, and it can be used as a standard for color correction in determining the photographic printing exposure amount. it can.

Therefore, in step 14, using the cumulative density function obtained from a plurality of original images as described above, the density information Z _K of each color of B, G, and R, which is the reference of color correction, is calculated by the following equation (11). ), (12). Y = CDF _G · AVE _G (K = B, G, R) (11) Z _K = CDF ^-1 (Y) (K = B, G, R) (12) Formula (2) , As is clear from FIG. 9, the cumulative density function CD
Since F is a function that is continuous and monotonically increasing at an arbitrary point, there is an advantage that the inverse function as described above can be obtained very easily and no exception processing is required.

In step 15, the color correction value C _KL for each original image is used by using the characteristic value and the reference density information for color correction.
Is calculated by the following equation (13) for each of B, G, and R colors. C _KL = Z _k −AVE _K (K = B, G, R) ... (13) Here, Z _k is an estimated value of the neutral color recorded on this photographic film, and therefore it is recorded on the original image. If the subject is a neutral color, the difference from the average value AVE _K is calculated to obtain C _kL
The absolute value of C _kL takes a small value, and when the color distribution of the subject is biased, the absolute value of C _kL takes a large value. Therefore, by using this color correction value, correction can be selectively applied to the color ferria.

Further, in step 16, step 12
In the same manner as above, it is identified whether or not the processed original image is the last original image recorded on one photographic film, and if it is the last original image, the processing is terminated (Yes in the figure), and if it is not the final original image. (No in the figure), the processes after step 2 are executed again. In the above description, the method of obtaining the color correction value based on the tone reproduction characteristic from one piece of photographic film has been described, but as described above, from the transport control circuit 72 of the scanning unit 22 via the system bus 74. The type of photographic film is identified by the bar code signal sent from the photographic film, and based on this identification result, the above cumulative density function is spread over a plurality of photographic films for a specific type or for each type within a predetermined classification. Can be accumulated.

In this case, a plurality of cumulative density functions obtained from a plurality of photographic films may be simply added. Due to the nature of the cumulative density function, this process is extremely easy. The result can be accumulated for a long period of time if saved in the auxiliary storage unit 106 that constitutes the information processing unit 26. In this way, when the accumulated cumulative density function is used as an auxiliary, the cumulative density function C is expressed by the following equation (14).
DF ″ _K (S) is obtained and replaced with the cumulative density function CDF _K (S) used in step 11. CDF ″ _K (S) = CDF _K (S) + β × CDF ′ _K (S) (K = B, G, R) (14) where CDF _K (S) is the cumulative density function obtained from the original image formed on the photographic film to be processed, and CDF ' _K (S) is the accumulated cumulative Is a density function, and β is a weighting coefficient. The weighting factor β is such that the number of cumulative density functions obtained from the processed photographic film is large (for example, 24
For each image density information), a small numerical value is given, and for an insufficient number (for example, four image density information), a large numerical value is given, which is a function of the number of image density information. There is. As a result, the processing for obtaining the color correction value is adjusted according to the certainty of estimating the neutral color recorded on the photographic film.

In this way, by supplementarily using the cumulative density function accumulated over a plurality of photographic films, the number of original images formed on the photographic film is small and a sufficient statistical amount cannot be obtained. In this case, or when the original image is extremely biased toward a particular subject, it is possible to obtain an appropriate color correction value based on the tone reproduction characteristics of the photographic film.

In order to specify or classify the type of the photographic film based on the identification of the type of the photographic film, the information processing unit 26 previously creates a correspondence table of the bar code signal and the identification code or the classification code.
This can be done by storing the data in the memory 102 or the auxiliary storage 106 of FIG. For classification, it is desirable to assign the same code to photographic films having similar characteristics.

In particular, when the above statistics are accumulated over a plurality of photographic films, the statistics can be obtained from a large number of original images. Is not necessarily the frequency distribution of the image density information, and the photodiodes 44a to 44c of the exposure unit 32 are
It may be the frequency distribution of the average transmitted light photometric values of the original image detected by. In this case, the same processing may be performed by replacing the image density information with the average transmitted light photometric value.

Further, instead of the average value of the image density information of each color shown in the equations (8) and (9), the average transmitted light photometric value can be used to determine the attribute of the original image. In such a case, the information of the average photometric value is processed in the exposure control unit 30 in the same manner as described above. Generally, in photometry of average transmitted light, a photometric element with a large light receiving area is used and a sufficient dynamic range is obtained, so a color separation filter having a spectral transmittance characteristic of a sufficiently narrow band is used and a wide density range is used. Accurate concentration can be measured. Therefore, as compared with the above-described processing based on the image density information of the image sensor, a signal that is more advantageous in color separation performance and accuracy is obtained, which is advantageous in performing color correction.

Further, the attribute of the original image is discriminated by the information of the simple and inexpensive image pickup system arranged near the exposure optical path, that is, the image density information obtained from the two-dimensional color CCD. The method of obtaining the statistic amount from the average transmitted light as described above can determine the exposure amount for the photographic original image with high reproducibility, and is effective in reducing the cost and downsizing the apparatus.

As described above, the image density information and the average transmitted light photometric value may be appropriately used according to the processing content such as the attribute determination of the original image and the calculation of the statistical amount, or both may be used throughout the entire processing. Alternatively, one of them may be used. In other words, the method according to the present invention is a method that can be applied extremely flexibly regardless of the form of the device, and the photometric system,
By combining the features of the imaging system, it is possible to realize an optimal system in terms of performance, processing time, and cost.

The color correction value C _kL obtained as described above is transmitted to the exposure control section 30 through the communication line 28 and used for determining the photographic printing exposure amount. (Method of Determining Photographic Printing Exposure Amount) Next, the determination of the photographic exposure amount in the exposure controller 30 will be described. The photographic printing exposure amount is determined according to the following equation (15). E _K = LATD _K −LATD _0K + γ × C _KL + E _0K (15) Here, E _K is the exposure amount (exposure value of exposure time) of each of B, G, and R colors, and LATD _K is the exposure unit 32. Photodiode 4
4a, 44b, 44c, the average transmitted light photometric value (logarithm) from the original image to be printed, LATD _0K is the average transmitted light photometric value (logarithm) from the standard original image, and C _KL is transmitted from the information processing unit 26. The corrected color correction value, γ is a coefficient for adjusting the strength of color correction, E _0K is the exposure amount (logarithmic value of the exposure time) set for the standard original image, K is the color of B, G, R,
L is the processing order of the original image.

In this way, the exposure amount is obtained based on the average transmitted light photometric value of the original image, and is corrected by the color correction value obtained in consideration of the tone reproduction characteristics of the photographic film. In this embodiment, the case where the exposure amount is determined based on the average transmitted light photometric value of the original image has been described, but it may be determined based on the characteristic value represented by the average value calculated from the image density information. .. Also in this case, the exposure amount is similarly corrected by the color correction value obtained in consideration of the tone reproduction characteristic of the photographic film.

[0085]

As described above, the photographic printing exposure amount control method of the present invention is applied to at least one of the image information by color of each original image or the average transmitted light amount with respect to the original image group formed by frame-arrangement on the color photographic film. The first statistic relating to the screen information, and a second statistic obtained by weighting the first statistic according to the attribute of each original image discriminated in the screen information, and further determining the second statistic. The feature is that the exposure amount for photoprinting of each original image is determined by obtaining the third statistical amount accumulated over the original images of multiple frames, so that the film type and the attribute of the original image are not processed for each pixel. Judge,
An appropriate printing exposure amount can be determined at high speed.

Further, since the weighting process is performed by multiplying the real value in the range of 0 to 1, it is possible to adapt to the attribute of the original image which changes in multiple steps. Further, since the weighting process is a binarization process in which 0 or 1 is multiplied, the process can be simplified. Moreover, since the original image group is made up of original images in the same film, the accuracy of attribute determination of the original images can be improved by accumulating information relating to the tone reproduction characteristics of the product type.

Further, since the original image group extends over a plurality of photographic films, the accuracy of attribute determination of the original image can be further improved. Further, since the plurality of photographic films are supposed to be photographic films belonging to a specific product type, by accumulating information related to the product type,
An appropriate color correction value can be obtained according to the tone reproduction characteristics of the photographic film.

Further, since the above-mentioned specific product belongs to a group classified according to its characteristic, by accumulating the information about the product in the group, it is appropriate according to the tone reproduction characteristic of the photographic film. It is possible to obtain a proper color correction value. Further, since the product type is identified by reading the bar code attached to the photographic film, the processing can be surely performed.

As described above, according to the photographic printing exposure amount determining method of the present invention, the correction amount for the photographic printing exposure amount is obtained based on the estimation of the neutral color of the photographic film.
The exposure conditions are set in advance for each type of photographic film, and the exposure conditions set according to the type of photographic film to be printed are not changed, and even if the deterioration of characteristics due to the state of latent image storage is maintained. It is possible to stably and efficiently produce photographic prints of the same quality.

Further, even when most of the original images on the photographic film are color ferrias obtained by photographing a subject in which a specific color is dominant, the attributes of the original image are discriminated and the exposure amount is decided according to the discrimination result. Since the related statistical amount is corrected, the neutral color recorded on the photographic film can be estimated with higher accuracy, and the color correction reference in determining the photographic printing exposure amount can be accurately obtained.

Further, even when the attribute of the original image is discriminated, the color is corrected, and the like based on the image density information, it is not necessary to make a pixel unit correction based on the statistical amount of the image density information. Even if the original image is scanned, the exposure amount for the photographic original image can be determined with high reproducibility. Further, since the same processing can be performed by the average transmitted light photometric value, it is possible to realize a more inexpensive device that does not require an imaging system.

Further, since the method according to the present invention can be applied regardless of the form of the apparatus, an optimum system can be realized in terms of performance, processing time and cost by combining the characteristics of the photometry system and the image pickup system. can do. In addition, according to the present invention, the type of photographic film is identified by reading the bar code attached to the photographic film, and based on the result of this identification, for each specific type or for each type belonging to a predetermined classification. , Since the statistic amount based on the tone reproduction characteristics of the photographic film is required, the number of original images recorded on the photographic film to be printed because the photographic film was cut in a short length, for example, in the case of reprinting or reprinting, If there are few enough statistics,
Even when the original image on the photographic film is extremely biased toward a specific subject, an appropriate correction amount can be obtained.

Therefore, it is possible to stably produce a photographic print of a certain quality regardless of variations in characteristics of photographic film and increase in variety, and regardless of simultaneous printing, additional printing, and reprinting. It is possible to obtain a great effect in promoting large rationalization and efficiency of the process.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a 135 photographic film used for explaining a method for determining a photographic printing exposure amount of the present invention.

FIG. 2 is a schematic view showing a schematic configuration of a photographic printing apparatus to which the photographic printing exposure amount determining method of the present invention is applied.

FIG. 3 is a configuration diagram showing a scanning unit in detail.

FIG. 4 is a configuration diagram showing in detail an image processing unit.

FIG. 5 is a diagram showing a part of image processing in a main scanning direction in the embodiment.

FIG. 6 is a diagram showing part of image processing in the sub-scanning direction in the embodiment.

FIG. 7 is a block diagram showing in detail an image processing unit.

FIG. 8 is a flowchart showing internal processing in the information processing unit.

FIG. 9 is a diagram showing an example of a cumulative density function obtained from a plurality of images.

FIG. 10 is a diagram showing an example of a frequency distribution for discriminating attributes.

FIG. 11 is a diagram showing an example of a cumulative density function for discriminating attributes.

FIG. 12 is a diagram showing an example of an LUT.

[Explanation of symbols]

 10 splice part 12 notch 14 bar code 20 spool 22 scanning part 24 image processing part 26 information processing part 28 communication line 30 exposure control part 32 exposure part 34 buffer part 38 diffusion part 40 photographic printing paper 74 system bus 100 photo printing device 102 memory 104 CPU 106 Auxiliary storage unit 108 Keyboard 110 Interface circuit 112 Display device 114 Communication circuit P Perforation F Photographic film I Original image

Claims (8)

[Claims] 1. A first statistic for at least one screen information of color-specific image information or average transmitted light amount of each original image for an original image group formed by arranging frames on a color photographic film, and the screen information. The second statistic obtained by weighting the first statistic is obtained according to the attribute of each original image determined in step 1, and the second statistic is stored as the third statistic accumulated over the original images of a plurality of frames. A method for controlling a photographic printing exposure amount, wherein the photographic printing exposure amount of each original image is determined by obtaining it. 2. The method according to claim 1, wherein the weighting process is a process for multiplying a real value in the range of 0 to 1. 3. The photographic printing exposure amount control method according to claim 1, wherein the weighting process is a binarization process in which 0 or 1 is multiplied. 4. The photographic printing exposure amount control method according to claim 1, wherein the original image group is composed of original images in the same film. 5. The photographic printing exposure amount control method according to claim 1, wherein the original image group extends over a plurality of photographic films. 6. The photographic printing exposure amount control method according to claim 5, wherein the plurality of photographic films are photographic films belonging to a specific product type. 7. The method according to claim 6, wherein the specific type belongs to a group classified according to its characteristics. 8. The method according to claim 6, wherein the type is identified by reading a bar code attached to the photographic film.