JPH09258348A - Photographic printing exposure deciding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high yield by appropriate printing regardless of the change of photographic exposure by calculating plural image characteristic values by performing at least two different kinds of weighting to two-dimensional image information. SOLUTION: The average transmitted light beams of the respective colors B, G and R of an original picture are received by photodiodes 44a to 44c through the photometric filters 42a to 42c of the colors B, G and R. The photometric signals of the colors B, G and R obtained by photoelectrically converting the received light quantity are supplied to an exposure control part 30 and A/D converted, and exposure is calculated based on the conversion data and correction quantity supplied from an information processing part 26. Namely, plural image characteristic values deciding printing exposure are obtained from the image information obtained by performing at least two different kinds of weighting to the two-dimensional image information on three surfaces of B, G and R of the original picture. Therefore, the use of the image characteristic values depending on the photographic exposure is avoided and the exposure width of the appropriate printing becomes small and high yield is obtained regardless of the change of the photographic exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention scans a frame image of a developed photographic film (hereinafter, also simply referred to as a film), that is, an original image by three-color separation scanning of blue (B), green (G) and red (R). The three-dimensional two-dimensional image information is obtained by reading, the three-dimensional two-dimensional image information is divided to define a plurality of segmented regions, and each of the segmented regions is associated with the segmented region corresponding to the segmented region.
The present invention relates to a photographic printing exposure amount determining method for calculating a plurality of image characteristic values based on two-dimensional image information of a surface and calculating an appropriate exposure amount for printing the original image on a photosensitive material based on the image characteristic values.

[0002]

2. Description of the Related Art The above-mentioned method for determining the exposure amount for photographic printing disclosed in Japanese Patent Laid-Open No. 5-93973 determines the exposure amount for printing based on the conventional average transmission density (LATD) of the entire area of an original image. Method, the image density obtained by scanning the original image described in Japanese Patent Publication No. 56-2691 for the purpose of automatically adjusting the exposure amount for the original image of the density feria, which is difficult to be satisfied by the method. Determine the maximum density, minimum density, average density, etc. for each area of the image, classify the original image based on those characteristic values, and determine the printing exposure amount of the original image by a function of the characteristic value set in advance for each classification. In the method described in Japanese Patent Laid-Open No. 195439/1989, it is intended to obtain an appropriate printing exposure amount regardless of whether the original image is upside down or upside down. 2D image information of the original image is obtained from the image density obtained by scanning, and the information of each pixel is arranged and rearranged according to this image information, and the characteristics of each region of the image are calculated based on the rearranged 2D image information. Find the value,
A method of classifying the original image based on those characteristic values and adjusting the exposure amount for the original image by a function of the characteristic value determined in advance for each classification. In the above method, the exposure amount is determined from the information for each original image. Since it is not possible to continuously and stably obtain the printing exposure amount within the same printing order, a great weight is given to the stability and continuity of the print density and color balance within the same printing order at the photo lab. Japanese Patent Publication Sho 63-523 that considers the shipping standards for photographic prints.
No. 67 and Japanese Patent Publication No. 3-19533, the similarity between the current frame to be printed and the adjacent frame is determined based on the image characteristic value of the previous frame. A method for determining the final exposure amount of the current frame by the average value of the exposure amount and the provisional exposure amount for the current frame, and to calculate the exposure amount of the current frame to be printed The similarity is calculated, and the provisional exposure amount is weighted to calculate the exposure amount according to the similarity, or the provisional exposure amount is weighted to calculate the exposure amount according to the relative relationship between the recording position and the current frame. Method, it is impossible to calculate an appropriate exposure amount when the similarity between the current frame and the previous frame is wrongly determined, and it is complicated to calculate the provisional exposure amount of a series of frames and the similarity to the current frame. A great deal Required between the processing capability of the photographic printing exposure device is intended to solve all the problem that the decrease.

[0003]

[Patent Document 1] Japanese Patent Application Laid-Open No. 5-93
The method for determining the photographic printing exposure amount described in Japanese Patent No.
Since the two-dimensional image information corresponding to the original image area is obtained from the average densities of the corresponding pixels of the two-dimensional image information on the G and R3 planes, the exposure amount for proper printing changes depending on the photographic exposure, and the exposure width must be wide. And the improvement of the dependence of the exposure amount on the exposure on the photographic exposure will lower the yield.
As a result, there has been a problem that the yield of proper printing tends to be lowered. The present invention has been made to solve the problem, and a photograph with a high yield of proper printing is obtained regardless of the change in photographing exposure. It is intended to provide a method for determining a printing exposure amount.

[0004]

SUMMARY OF THE INVENTION According to the present invention, an original image on a developed photographic film is scanned in three colors of blue (B), green (G), and red (R) and read to read it in two dimensions. Obtaining image information, dividing the three-dimensional two-dimensional image information to define a plurality of segmented areas, and regarding each of the segmented areas, a plurality of segmented areas is determined based on the three-dimensional two-dimensional image information corresponding to the segmented areas. In a photographic printing exposure amount determination method of calculating an image characteristic value and calculating an appropriate exposure amount for printing the original image on a photosensitive material based on the image characteristic value, the plurality of image characteristics corresponding to the divided areas When the values are calculated, the plurality of image characteristic values are calculated by weighting at least two different kinds of two-dimensional image information of the three surfaces, thereby achieving the above object. To do.

That is, in the photographic printing exposure amount determining method of the present invention, a plurality of different image characteristic values for determining the printing exposure amount are weighted to at least two different types of two-dimensional image information on the B, G and R3 surfaces of the original image. By using the image information obtained from the image information, it is possible to avoid the use of image characteristic values depending on the shooting exposure, and it is possible to obtain a high yield by reducing the exposure width of proper printing regardless of changes in the shooting exposure. it can.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for determining a photographic printing exposure amount of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a 135 film which has been subjected to a baking process. In FIG. 1, a plurality of films F having original images 11 which have been developed and arranged at a predetermined pitch are joined by a splice 10. It is formed into a roll. In the rolled film F, a notch 12 indicating the center of each original image position is formed on the film edge in the notch step before the photo printing step. The notch 12 is detected to control the positioning of the film F in the printing process. A well-known perforation 13 is formed on the side of the film F in advance, and a bar code 14 indicating the type of film is also formed as shown in the figure. The film F is not limited to the 135 film, and may be a film of other size.

The above-mentioned roll-shaped film F is subjected to a baking process in the photographic printing apparatus shown in FIG. In FIG. 2, the film F is set on the supply spool 20,
It is taken up by the take-up spool 21 via a predetermined transport path. A scanning unit 22 is provided in the middle of the route,
The original image of the film F is separated into each color of B, G and R by the scanning unit 22 and scanned and read. The image information of the B, G, and R3 surfaces obtained thereby is 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.

The information processing unit 26 calculates a correction amount for each original image from the image density information by a process described later, and sends a signal of the correction amount to the exposure control unit 30 through the communication line 28. The film F that has passed through the scanning unit 22 is provided between the scanning unit 22 and the exposure unit 32 in order to absorb the difference in the transport speed of the film F between the two units and at the same time to scan a plurality of original images in advance before exposure. It is sent to the exposure unit 32 through the buffer unit 34. Note that the transport path between the scanning unit 22 and the exposure unit 32 has a length corresponding to a maximum of 24 shots 135 film, and thus, for almost all original images recorded on one 24 shots 135 film. The image density information can be obtained prior to exposure.

Each original image formed on the film F is positioned in the exposure section 32 and is exposed by the light uniformized by the diffusion section 38 of the light from the light source 36. Then, the image light passing through the original image is optically formed by the lens 54 on the photographic printing paper 40 made of a photosensitive material. At that time, B, G, and B of the original image are passed through the photometric filters 42a, 42b, and 42c of B, G, and R colors.
The average transmitted light of each R color is the photodiode 44a, 44
The light is received by b and 44c. The photometric signals of B, G, and R colors obtained by photoelectrically converting the received light amount are supplied to the exposure control unit 30 and A / D converted, and the converted data and the information processing unit 2
The exposure amount is calculated based on the correction amount supplied from 6.

The exposure control unit 30 is a subtractive cut filter 5 for yellow (Y), magenta (M), and cyan (C) arranged above the exposure unit 32 based on the obtained exposure amount.
0a, 50b, 50c and the operation time of the shutter 52 disposed below the exposure unit 32 are controlled. That is, the cut filters 50a, 50b, 50c and the shutter 52 are inserted into the exposure optical path only for the operation time, and the exposure given to each color photosensitive layer of the photographic printing paper 40 is adjusted. Each time this exposure is completed, printing paper 4
0 is conveyed by a predetermined distance in preparation for the next exposure, and the film F is conveyed so that the original image to be printed next is positioned in the exposure section 32. In this way, the original image 11 of the film F is sequentially printed.

FIG. 3 shows the structure of the scanning unit 22 in detail. In the scanning unit 22, the light from the light source 59 is made into substantially parallel light by the lens 60, and the parallel light is arranged in parallel with the transport direction of the film F and the color separation filter 62 is arranged.
Color separation into B, G, and R colors is performed by a, 62b, and 62c. The film F is separated by the colors B, G, and R, and the film F is irradiated with the light that has passed through the slits 64.

The light transmitted through the film F is a CCD arranged at a position corresponding to the irradiation light of each of B, G and R colors.
Photoelectric conversion is performed by the line sensors 68a, 68b, 68c. Each of the CCD line sensors 68a, 68b, 68c is composed of 2048 pixels, and is 32 in the width direction of the film F.
A one-dimensional image sensor capable of scanning over a length of mm is used. With these, main scanning is performed for 32 mm in the width direction of the film F, and the read image signals for the respective colors B, G, R are supplied to the image processing unit 24.

The notch 12, the splice 10 and the bar code 14 formed on the film F are detected by the detectors 70a, 70b and 70c, and the detection signals are supplied to the transport control circuit 72. Transport control circuit 7
2 processes these detection signals, sends the results as a notch signal, a splice signal and a bar code signal to the image processing unit 24 and the information processing unit 26 via the system bus 74, and outputs a pulse based on the notch signal and the splice signal. The motor 75 is driven to control the transport of the film F, and the transport pulse is supplied to the image processing unit 24 as a synchronization signal for sampling the image signal.

The film F is conveyed by the pulse motor 75 at 0.25 mm / pulse, and the sub-scanning is carried out accordingly.

FIG. 4 shows a detailed structure of the image processing section 24. The image processing section 24 performs the following signal processing. CCD line sensors 68a, 68b of the scanning unit 22,
The image signal supplied from 68c is amplified by the amplifier circuit 80, sampled by the sample hold circuit 82 and the A / D converter 84, and converted into a digital signal. Here, the timing control circuit 86 sends a drive signal for driving the CCD line sensors 68a, 68b, 68c and controls the sampling timing. The sampling number is 1 for one main scan
28 times, and A / D conversion is processed by 16 bits.
The digitized image signal is converted into a density value by a look-up table (LUT) 88 stored in a ROM or the like and stored in the image buffer 90. The conversion table shown in Formula 1 is described in the LUT 88.

[0017]

[Equation 1]

X in the above equation is the input of the conversion by the LUT 88,
Y is an output, a is a constant relating to conversion of photometric density determined by the spectral characteristics of imaging in the scanning unit 22 to printing density determined by the spectral sensitivity of the printing paper, and b is a constant relating to removal of the influence of dark current in imaging. Is.

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 the conversion table to be used among them is selected in advance by the CPU 92. The conversion table used does not have to be the same for each color of B, G and R, and may be different.

As described above, 16-bit line image density information consisting of 128 pixels (hereinafter referred to as primary line image density information D
(a) is stored in the image buffer 90. Then C
The PU 92 takes out the primary line image density information Da in synchronism with the carrier pulse from the carrier control circuit 72 of the scanning unit 22, performs the following rounding processing, and executes the memory 94 for each scanning line.
Image processing in the main scanning direction is performed. Where CP
Since the effective image area in the main scanning direction (primary line image density information Da) of U92 differs depending on the format of the film F, U92 is a target for rounding in the main scanning direction which is stored in advance according to the format of the film F. The image area and the number of pixels to be rounded are set, and each pixel in the set image area is rounded by the set number of pixels. That is, the CPU 92 processes the line image density information of a predetermined number of pixels as described above, and then stores it in the memory 94 for each scanning line.

FIG. 5 shows an example in which a predetermined number of pixels is set to 16 and is processed into linear image density information for 135 films and 110 films. In the primary line image density information Da obtained from the 135 film, the image area corresponding to the central width of 20 mm is set as the effective area, and the pixel number 80 corresponding to the length is divided by the predetermined pixel number 16. The numerical value of 5 is set as the number of rounded pixels. Also, 110
In the primary line image density information Da obtained from the film,
The image area corresponding to the width of 12 mm at the center is set as the effective area, and the number 3 obtained by dividing the number of pixels 48 corresponding to the length by the predetermined number of pixels 16 is set as the number of rounded pixels.

The rounding process normally takes the arithmetic mean of the image density information of the number of rounded pixels, which has the effect of reducing the influence of noise contained in the image signal. However, rounding does not necessarily have to target all pixels in the selected image area,
A method of taking an upper arithmetic average with appropriate thinning and a method of thinning only a predetermined number of pixels and not taking an arithmetic average are also effectively used when the calculation speed is taken into consideration.

By the image processing in the main scanning direction as described above, the secondary line image density information Db consisting of a predetermined number of pixels, here 16 pixels, is obtained regardless of the format of the film F, and the secondary line thereof is obtained. The image density information Db is stored in the memory 94 as line image density information corresponding to many scanning lines as the film F is conveyed. Here, the management of the correspondence between the original image formed on the film F and the secondary line image density information Db stored in the memory 94 becomes a problem.
The management is performed based on the notch signal. That is, as described above, the notch 12 is provided corresponding to the central position of the original image 11, is detected by the scanning unit 22, and the notch signal is sent to the CPU 92 via the system bus 74.
When the CPU 92 receives the notch signal, it counts the carrier pulses, extracts the primary line image density information Da stored in the image buffer 90 from the time when the predetermined processing start count value is reached, and outputs the secondary line image density information Da. The above-described image processing in the main scanning direction, in which the image density information Db is processed and then stored in the memory 94, is repeated until a predetermined number of scanning lines is reached.

The address of the secondary line image density information Db stored in the memory 94 corresponds to the notch signal and is stored in the memory 94.
Is stored in a predetermined area of. Thereby, the secondary line image density information Db is managed corresponding to the position of the original image 11 formed on the film F. However, this correspondence is B, G,
CCD line sensors 68a, 68b for each color of R,
It is related to the arrangement of 68c. Therefore, the predetermined process start count value is selected and set according to the color from the constants stored in advance. The selection can be made by a switch (not shown) provided inside the image processing unit 24.
By this selection, the image processing unit 24 can be made to have a common configuration for each color of B, G, and R, and its internal processing can also be made common. Also, by operating them in parallel, an extremely high processing speed can be achieved.

The CPU 92 further retrieves the above-mentioned 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 processes the information. It is sent to the unit 26. The effective image area in the sub-scanning direction (the number of scanning lines) may also differ depending on the format of the film F. So CPU
Reference numeral 92 sets the number of scanning lines stored in advance according to the format of the film F as the number of scanning lines of the two-dimensional image density information of the above-mentioned predetermined format. For example, the scanning unit 22 scans once every 0.25 mm. As a result, the number of scanning lines corresponding to the processing target area 32 mm of the full size original image of 135 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. 2 of those same predetermined formats
In order to set the number of scanning lines of the three-dimensional image density information, the CPU 92
The number of scanning lines stored in advance according to the format of the film F is set as the predetermined number of scanning lines.

In FIG. 6, the CPU 92 sets a predetermined number of scanning lines, that is, the number of pixels in the sub-scanning direction to 16, and further performs rounding processing in the sub-scanning direction in accordance with the set number of scanning lines.
An example of processing into two-dimensional image density information including a predetermined number of pixels in the sub-scanning direction is shown. In FIG. 6, for the secondary line image density information Db obtained from the 135 full-size original image, the number 8 obtained by dividing the number of scanning lines 128 by the predetermined number of sub-scanning pixels 16 is the number of rounded scanning lines. The secondary line image density information D set and obtained from the 135 half size original image
For b, the number of scanning lines is 64 and the predetermined number of sub-scanning pixels is 16
The numerical value 4 divided by is set as the number of scanning lines for rounding. As in the case of image processing in the main scanning direction, the rounding processing thereby takes an arithmetic average of the image density information in the sub-scanning direction and gives the effect of reducing the influence of noise included in the image signal. . However, the rounding does not need to target all the stored secondary line image density information Db, and a method of taking an arithmetic average after appropriately thinning it out, or thinning out a predetermined number of scanning lines It is also possible to use a method that does not take the arithmetic mean alone, and these methods are effective when the calculation speed is taken into consideration.

Regarding the above processing speed, the image processing in the main scanning direction does not have to be performed in response to all the carrier pulses, but may be performed intermittently. Thereby, 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 film F.

By the image processing in the sub-scanning direction as described above, two-dimensional image density information consisting of a predetermined number of pixels, here 16 × 16 pixels, is finally obtained regardless of the format of the film F. Is sent to the information processing unit 26. Therefore, the information processing unit 26 whose detailed configuration is shown in FIG.
The common processing can be performed regardless of the format of the film F.

In FIG. 7, the two-dimensional image density information regarding each of the colors B, G and R sent from the image processing unit 24 is stored in the memory 102 via the system bus 74. CP
U 104 reads out the two-dimensional image density information stored in the memory 102, and the original images 11 formed on the film F are read.
Calculate the correction amount for. This correction amount is transmitted to the exposure control unit 30 via the interface circuit 114 through the communication line 28. The notch signal, the splice signal and the bar code signal sent from the conveyance control circuit 72 of the scanning unit 22 shown in FIG. 3 via the system bus 74 are also stored in the memory 1.
02, and is processed by the CPU 104.

Auxiliary storage unit 10 included in the information processing unit 26
6 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. This allows the information to be stored even when the power is cut off, so that not only can the information be stored for a long period of time, but the stored information can be processed using an external independent device, and constants can be initialized. It can be changed or changed. Further, a display 112 and a keyboard 108 are also provided for operation, and input / output can be performed via the interface circuit 110.

Next, the CPU 10 in the information processing unit 26
The internal processing of the method for determining the exposure amount for photographic printing of the present invention according to No. 4 will be described with reference to the flowcharts of FIGS. C
In step 1 of FIG. 8, the PU 104 reads B from the memory 102,
Two-dimensional image density information regarding each color of G and R is extracted,
Set to variable X _K (i, j). Where K is B, G,
Each color of R is shown, i is a pixel position in the main scanning direction, and j is a pixel position in the sub scanning direction. Then in step 2 the variable X
Two weighted image density information D (i, j) and D '(i, j) are calculated from _K (i, j) by the equation (2).

[0032]

[Equation 2]

U, v, w and u ', v', w'of the equation (2)
Is u ≠ u ′, v ≠ v ′, w ≠ w ′, and preferably u + v + w = 1 and u, v, w ≧ 0, u ′ + v ′ +.
a value satisfying the conditions of u ', w', w'≥0 when w '= 1,
More preferably, any one of u, v and w is 1 or approximately 1 and the other two are 0 or approximately 0, for example w = 1, u = v =
Any two of 0, u ′, v ′ and w ′ are 0.5 or about 0.5 and the other one is 0 or about 0, for example u ′ = v ′ =
0.5 and w '= 0.

Next, in step 3, D (i, j) and D '
10 to 14 of the original image 11 from (i, j), respectively.
Average value av and maximum value ma for the segmented area shown in
Among x, the minimum value min, and the standard deviation sd, the characteristic value required below is calculated. The divided area of the original picture 11 is
(AL) is the whole area of the original picture, (UL), (UR), (L
L), (LR), and (CN) are the upper left, upper right, lower left, lower right, and central divided areas of the original image, respectively, (UP) = (UL)
+ (UR), (LW) = (LL) + (LR) are the upper and lower divided areas of the original image, respectively (LS) = (UL) +
(LL) and (RS) = (UR) + (LR) are divided areas on the left and right sides of the original image, respectively (PR) = (UP) + (L
W) = (AL)-(CN) is the peripheral division area of the original image.

Next, in steps 4 to 7, information D (i, j), D'of each pixel is obtained according to the two-dimensional image density information.
Arrange and rearrange (i, j). The sorting and rearranging method includes a method of rearranging the rows or columns in the ascending or descending order according to the average value (or total value) of the rows or columns of the two-dimensional image density information, a characteristic value of each divided area, For example, there is a method of rearranging the divided areas as they are according to the average density value in the area, and either method may be adopted.
The illustrated example shows the case where the latter method is adopted. That is, in step 4, the average density value av of the divided areas (UL) and (UR), that is, (UP) is compared with the average density value av of the divided areas (LL) and (LR), that is, (LW), and the upper side ( U
When the average density value av of P) is large, the process proceeds to step 6.

On the contrary, when the average density value av of the lower divided area (LW) is large, the procedure proceeds to the rearranging / rearranging operation of step 5. The function SWAP {a, b} in step 5 is a function for exchanging the values of a and b. Here, the two-dimensional image density information of the divided areas (UL) and (LL) is exchanged, and (UR) and (LR) are exchanged. ) Means exchanging the two-dimensional image density information. After the sorting / sorting operation, the process proceeds to step 6.

In step 6, as in step 4, the average density value av of the divided areas (UL) and (LL), that is, (LS).
And the size of the average density value av of the divided areas (UR) and (LR), that is, (RS), are compared, and the average density value a of the left side (LS) a
If v is large, the process proceeds to step 8 in FIG. On the contrary, when the right side (RS) average density value av is large, the procedure proceeds to the sorting and rearranging operation in step 7. Function SWAP of step 7
The two-dimensional image density information of the divided areas (UL) and (UR) is exchanged with each other, and the two-dimensional image density information of the divided areas (LL) and (LR) is exchanged. The two-dimensional image density information D (i, j) and D '(i, j) obtained by the equation (2) above the original image 11 that has been subjected to steps 4 to 7 as described above are respectively D _n (i,
j) and D _n ′ (i, j). After the rearrangement / sorting operation, the process proceeds to step 8.

By performing the sorting and rearranging operations in steps 4 to 7 as described above, the subsequent two-dimensional image density information D _n (i, j) and D _n ′ (i, j) is the image. Although the two-dimensional information as described above may be lost, it can be uniformly handled regardless of whether the original image is upright or the position of the main highlight portion of the image. In addition, when the normal upside down information of the original image is known in advance or when the operator inputs the normal upside down information from the keyboard 108, steps 4 to 7 are skipped and the given top and bottom information is also stored. The rearranging and rearranging operations may be performed for and.

In steps 8 to 9, characteristic values of various divided areas are obtained by using the above-described two-dimensional image density information D _n (i, j) and D _n ′ (i, j) of the original image 11, and those characteristics are obtained. The image classification characteristic value CL _p and the exposure calculation characteristic value EX _p as a function of the value are calculated. The above-mentioned characteristic values may be used as they are for CL _p and EX _p . Alternatively, regardless of the characteristic value obtained by using the two-dimensional image density information D (i, j), D ′ (i, j), the two-dimensional image density information X _B (i, j) for each color of B, G, R is obtained. ), X _G (i, j) or X _R (i, j)
Characteristic value X _'B, X' divided areas obtained using _G or X _'R
The image classification characteristic value CL _p and the exposure calculation characteristic value EX _p may be calculated as a function of

In this embodiment, CL _p and EX _p are P = 1 to 1
4 of 14 characteristic values each, and CL
The case of _p = EX _p will be described, but the functional form and the number of each characteristic value are not limited to this. In general, CL _p ≠ EX _p may be satisfied. However, in this embodiment, a large number of original image populations are statistically analyzed, and when classifying them into a plurality of preset sets described later, the 14 characteristic values having the best classification ability are shown in the equation (3). Was selected.

[0041]

(Equation 3)

The max (AL) and the like in the equation 3 are shown in FIG.
As is clear from the step 3 described above, the two-dimensional image density information D _n (i, j), D _n ′ (i,
j) is the maximum value or the like.

Then, at step 10, the linear primary sum based on the equation 4 is calculated using the image classification characteristic value CL _p and the coefficients stored corresponding to a plurality of predetermined sets.

[0044]

(Equation 4)

In the equation (4), p is 1 to 14 using the example of the equation (3), and q is an identifier for a predetermined set. It is assumed that the set is determined as follows according to the degree of the amount to be corrected with respect to the printing exposure amount calculated by LATD in order to obtain a photographic print with proper exposure from the original image, for example.

Set 1 Set of original images requiring extreme negative correction Set 2 Set of original images requiring slightly negative correction Set 3 Set of original images not requiring correction Set 4 Set of original images requiring slightly positive correction Set 5 Set of original images requiring extreme plus correction In addition, α (p, q) and β _q are values stored according to the set q of original images, and statistically represent a population of a large number of original images. The optimum value can be obtained by using a method. Here, the example in which the image set is set according to the degree of the exposure correction amount has been described, but it is also possible to set the set according to the scene of the original image such as a flash scene, a backlight scene, or a snow scene.

Next, in steps 11 to 12, it is judged which set the original image 11 belongs to by mutually evaluating F _q calculated for each image set in step 10. For example, the above F _{1 to} F ₅ are compared, and it is determined that the original picture 11 belongs to the set having the maximum value.

In step 13, the exposure calculation characteristic value EX
The density correction value CV _q when it is determined that each original image belongs to the image set q by using _p is obtained by the regression equation shown in the following Expression 5.

[0049]

(Equation 5)

In the equation (5), p is 1 to 14 using the example of the equation (3), and ξ (p, q) is a preset population of the original images for each image set using a statistical method. The coefficient, η _q, is a constant.

On the other hand, the color correction value C ″ _KL is, for example, Japanese Patent Laid-Open No.
No. 6939, that is, the original image B,
It can be obtained by a method of determining the color correction amount based on the cumulative density function (CDF) of each color of G and R and the neutral color.

Density correction value CV obtained as described above
_{The q} and the color correction value C ″ _KL are transmitted to the exposure control unit 30 through the communication line 28 and used by the exposure control unit 30 for determining the photographic printing exposure amount.

In the exposure controller 30, the exposure amount for photographic printing is determined according to the equation (6).

[0054]

(Equation 6)

In the equation (6), E_KIs B, G, R
Color exposure (logarithmic value of exposure time), LATD_KIs the exposed part
In 32, the photodiodes 44a, 44b, 44c
Transmitted light from the original image for printing
Photometric value (logarithm), LATD0 _KIs the average transparency from the standard original
Overlight metering value (logarithm), C ″_KLIs transmitted from the information processing unit 26
The adjusted color correction value, μ is a parameter for adjusting the strength of color correction.
Number, CV_qIs the density correction transmitted from the information processing unit 26.
Value, ν_qIs a coefficient for adjusting the strength of density correction, E0_K
Is the exposure amount set for the standard original image (logarithm of exposure time)
Value) and K indicate each color of B, G, and R. Therefore, the exposure dose is
Density correction calculated based on the average transmitted light photometric value of the original image
Corrected by quantity and color correction value.

In this example, the average transmitted light photometric value LATD _K is used, but the average value of the image density may be used instead. Further, ν _q can also change the degree of strength and weakness of the density correction according to the image set q. That is, in the case of the image classification described above, five kinds of image sets are set according to the degree of the amount of density correction to obtain a print with proper exposure. For example, “set 5: extreme plus correction is performed. If you want to enhance the degree of correction only for the required set of original images, you can set a large numerical value for ν ₅ (usually 1).

As a result, even if the tendency of the scene distribution changes according to the season or the photographic characteristics of the negative film and the photographic paper change, the finishing quality can be adjusted to be optimum. In addition, the settings can be changed individually at each photo lab or the like, so that the difference in the scene distribution depending on the region can be considered.

In this embodiment, the case where the method for determining the photographic printing exposure amount of the present invention is applied to the calculation of the density correction amount has been described. However, the present invention is applied to the calculation of the color correction amount and classified by chromaticity. A set such as a color ferria set or a heterogeneous light source set is preset, and an evaluation amount is calculated by a linear first-order sum of the image characteristic value of the original image and / or a function of the image characteristic value, and the original image is calculated based on this evaluation amount. It is also possible to calculate the color correction amount for the original image by determining which image set it belongs to.

Specific examples in which the method for determining the photographic printing exposure amount of the present invention is compared with the method described in JP-A-5-93973 will be described below.

Comparative Example Using the film F shown in FIGS. 1 to 7 and the photographic printing apparatus, as a method described in Japanese Patent Laid-Open No. 5-93973, the original image 11 from the image processing section 24 is composed of 16 × 16 pixels B,
G, R two-dimensional image density information X _B (i, j), X _G (i,
j), X _R (i, j) to D (i, j) = (X _B (i,
j) + X _G (i, j) + X _R (i, j)) / 3 is used to calculate the image classification characteristic value CL _p and the exposure calculation characteristic value EX _p , An exposure amount E _K is obtained based on the CL _p and EX _p , and printing exposure is performed.

Example 1 To calculate CL _p and EX _p , D (i, j) = X
_B (i, j) / 4 + X _G (i, j) / 4 + X _R (i, j)
/ 2 and D '(i, j) = X _B (i, j) / 3 + X
Except that _G (i, j) / 3 + X _R (i, j) / 3 was used
Similarly to the comparative example, the exposure amount E _K is obtained and printing exposure is performed.

Example 2 To calculate CL _p and EX _p , D (i, j) = X
_B (i, j) / 4 + X _G (i, j) / 2 + X _R (i, j)
/ 4 and D '(i, j) = X _B (i, j) / 3 + X
Except that _G (i, j) / 3 + X _R (i, j) / 3 was used
Similarly to the comparative example, the exposure amount E _K is obtained and printing exposure is performed.

Example 3 D (i, j) = X to calculate CL _p and EX _p
B (i, j) / 2 + X _G (i, j) / 4 + X _R (i, j)
/ 4 and D '(i, j) = X _B (i, j) / 3 + X
Except that _G (i, j) / 3 + X _R (i, j) / 3 was used
Similarly to the comparative example, the exposure amount E _K is obtained and printing exposure is performed.

Appropriate printing yields of the original images according to the above Comparative Examples and Examples 1 to 3 and results of exposure width of printing exposure are shown in Table 1.

[0065]

[Table 1]

The yield in Table 1 is the value for the result of printing the original image of 4163, and the exposure width is -4 EV when the exposure width at the time of photographing is used.
To +6 EV for the printing of 88 originals. As is clear from the results in Table 1, the method of the present invention provides a stable baking exposure width and a higher yield than the method described in JP-A-5-93973.

The present invention is not limited to the above embodiment, but X _B (i, j), X _G (i,
j), X _R (i, j) with a weight of 1/4 of the weight of 0
And reduce the weight of 1/2 to the sum of the three weights to 1
If the value is increased to 1 so that the yield becomes even higher, the result is that the baking exposure width becomes stable.
It has been found that it is preferable to make the weight of _R (i, j) close to 1. Further, the small weights do not have to have the same value, and even if they are different, the same effect as the embodiment can be obtained.

[0068]

As described in detail above, according to the method of determining the exposure amount for photographic printing of the present invention, it is possible to obtain a good print with a stable yield and a higher yield than the method disclosed in JP-A-5-93973. You can

[Brief description of drawings]

FIG. 1 is a partial plan view showing an example of a film used in a method for determining a photographic printing exposure amount of the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a photographic printing apparatus used in the photographic printing exposure amount determining method of the present invention.

FIG. 3 is a partial configuration diagram showing details of a scanning unit of the apparatus of FIG.

FIG. 4 is a partial configuration diagram showing details of an image processing unit of the apparatus of FIG.

FIG. 5 is an explanatory diagram showing an example of performing image processing on 16 pixels in a main scanning direction.

FIG. 6 is an explanatory diagram showing an example of performing image processing on 16 pixels in the sub-scanning direction.

7 is a partial configuration diagram showing details of an information processing unit of the apparatus of FIG.

FIG. 8 is an internal processing flowchart in an information processing unit.

9 is a flowchart of the internal processing in the information processing unit following FIG.

FIG. 10 is a plan view showing an example of a divided region of two-dimensional image information of an original image.

FIG. 11 is a plan view showing an example of a divided region of two-dimensional image information of an original image.

FIG. 12 is a plan view showing an example of a divided area of two-dimensional image information of an original image.

FIG. 13 is a plan view showing an example of a divided region of two-dimensional image information of an original image.

FIG. 14 is a plan view showing an example of a divided region of two-dimensional image information of an original image.

[Explanation of symbols]

 20 Supply Spool 22 Scanning Section 24 Image Processing Section 26 Information Processing Section 28 Communication Line 30 Exposure Control Section 32 Exposure Section 34 Buffer Section 38 Diffusing Section 40 Photographic Paper F Photographic Film

Claims (4)

[Claims] 1. Three-dimensional two-dimensional image information is obtained by scanning an original image on a developed photographic film by three-color separation scanning of blue (B), green (G), and red (R), and reading the three-sided image information. The two-dimensional image information is divided into a plurality of divided areas, and a plurality of image characteristic values are calculated for each of the divided areas based on the three-dimensional image information of the three surfaces corresponding to the divided areas, In the photographic printing exposure amount determining method for calculating an appropriate exposure amount for printing the original image on the photosensitive material based on the image characteristic value, in calculating the plurality of image characteristic values corresponding to the divided area, A method for determining a photographic printing exposure amount, characterized in that the plurality of image characteristic values are calculated by performing different weighting on at least two types of two-dimensional image information of three surfaces. 2. Of the at least two kinds of weights, the weight for the two-dimensional image information on any one of the B, G, and R3 surfaces is approximately 1, and the weight for the two-dimensional image information on the other two surfaces is approximately. The method according to claim 1, wherein the exposure amount is 0. 3. Of the at least two types of weights, the weight for two-dimensional image information on any one of the B, G, and R3 surfaces is substantially 0, and the weight for two-dimensional image information on the other two surfaces is substantially zero. The method for determining the exposure amount for photographic printing according to claim 1, wherein the method is 1. 4. A weight for two-dimensional image information on the R surface>
4. The photographic printing exposure amount determining method according to claim 1, wherein the weight is a weight for two-dimensional image information on the B and G2 surfaces.