JPH0570136B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention automatically determines the exposure amount or exposure correction amount for printing according to the size information of an original film such as a negative film. The present invention relates to a photographic printing exposure determining device.

(Technical background of the invention and its problems) In a photo printing apparatus, the density of the original film (for example, negative film) must be measured in order to determine the printing exposure amount or exposure correction amount.
Conventionally, an optical sensor such as a photodiode placed near the optical path of the printing optical system measures the average density of negative film using LATD (Large Area
Transmittance Density). Since LATD measures the light by collecting the light that has passed through the entire screen of the negative film, it is well known that sub-effect areas occur. When the film size is different, the amount of light that passes through the film screen and enters the sensor is different, so it is necessary to change the exposure amount and correction amount. There was a problem that photo printing became complicated because the photometry area had to be changed depending on the size and the exposure formula had to be selected each time.

There is also a method in which the density of a film image is read as a large number of pixels, and the exposure amount is determined by correcting the sub-effect area. However, it is extremely labor-intensive to develop an exposure amount determination formula and an exposure amount correction formula for each film size.
For this reason, various methods have been considered to determine the exposure amount with high precision using a small number of exposure amount determination formulas and correction formulas without depending on the film size as much as possible, but the devices are expensive, large, and have complicated mechanisms. It had the drawback of being prone to breakdowns. There is a need for a method that is small, inexpensive, easy to use, and highly accurate in determining the exposure amount.

(Object of the Invention) The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to detect image information of an original film such as a negative film accurately and in detail with a simple configuration, and to detect size information of the original film. Accordingly, it is an object of the present invention to provide a photographic printing exposure amount determination device that automatically determines an exposure amount depending on the size.

(Summary of the Invention) The present invention relates to a photographic printing exposure determining device, which includes a photometric means for dividing a film image into a large number of pixels and measuring the light, a logarithmic conversion means for converting the photometric value into a density value, and each of the above-mentioned pixels. memory means for storing the density value of the pixel according to the arrangement of the pixels in the pixel;
size determination means for determining the film screen size; pixel compositing means for dividing the entire area into a predetermined number of divisions to form composite pixels; image information creation means for calculating image information such as screen center density and maximum density using the average density value of the composite pixels; and an exposure amount determination means for determining the exposure amount based on a predetermined exposure amount determination formula that is common regardless of the screen size, using the image information of the composite pixel obtained by the image information creation means. It is.

(Embodiment of the Invention) FIG. 1 shows an example in which a charge accumulation type two-dimensional image sensor 10 such as a CCD used in the present invention is applied to a conventional photographic printing apparatus, in which the printing section is guided by a negative carrier 1. The negative film 2 sent to is yellow (Y) and magenta (M).
It is designed to be illuminated by a light source 4 through three primary color filters 3 of and cyan (C), and the transmitted light from the negative film 2 passes through a lens system 5 and a black shutter 6 and reaches photographic paper 7. There is. The photographic paper 7 is wound around a feed roller 7A, and is wound around a roller 7B in synchronization with the conveyance and stopping of the negative film 2.
Red (R) is placed near the lens system 4 side of the negative film 2.
An optical sensor 8 such as a photodiode is provided to detect image density information of the three primary colors of green (G) and blue (B), and the amount of exposure is determined based on the detection signal of this optical sensor 8. Photo printing is now available. LATD is simply the measurement of the transmitted light that has passed through the negative film and the density conversion, and is the average density that includes the image density and the base density.
The exposure amount determined by LATD generates a sub-effect area, and conventionally, the exposure amount is corrected by obtaining an exposure correction amount determined visually or using a scanner. A two-dimensional image sensor 10 is provided in the vicinity of the negative film 2 in a state where the optical axis LS of the light source 4 and the negative film 2 is inclined. A lens system 11 is provided to form an image at the center, and a substrate 12 on which a processing circuit such as an IC for image processing is mounted is attached to the back side of the unitized detection device.

Here, the two-dimensional image sensor 10 includes an imaging unit 101 that optically captures an image, as shown in FIG.
, an accumulation section 102 for accumulating the charges transferred from the imaging section 101, and an output register section 103 for outputting the charges accumulated in the accumulation section 10.
The drive signal 1 from the drive circuit is
By controlling 01S to 103S, two-dimensional (area) image information is photoelectrically converted and an analog image signal PS is serially output from the output register section 103. Further, the circuit configuration mounted on the board 12 is, for example, as shown in FIG.
The light irradiated on the imaging unit 101 of the image sensor 10 is output as an image signal PS from the output register unit 103, and is sampled and held in the sample hold circuit 21 at a predetermined sampling period, and the sample value is A.D.
The converter 22 converts it into a digital signal DS.
The digital signal DS from the AD converter 22 is input to the logarithmic conversion circuit 23, where it is logarithmically converted, and a concentration signal is obtained.
It is converted into a DN and later written into the memory 25 via the write control circuit 24. Note that the write control circuit 2
4 inputs a reading speed signal RS for driving the image sensor 10 from the drive circuit 20 to read image information at a constant speed;
The density signals DN are sequentially written to predetermined positions in the memory 25 in accordance with the driving speed of the memory 25.

In such a configuration, when performing normal photographic printing, the optical sensor 8 detects the transmitted light of the negative film 2 that has been conveyed and is stationary in the printing section, and the LATD for each of the three primary colors, RGB, is used to detect the transmitted light. The filter 3 is adjusted according to the determined exposure amount, the black shutter 6 is opened, and the photographic paper 7 is exposed to the determined exposure amount.

In this invention, for example, there is a
Image scanning type two-dimensional image sensor 1 consisting of CCD
0 is provided, and the entire screen of the negative film 2 is electrically scanned to measure the density of the image into a large number of parts, thereby detecting image information. That is, by applying predetermined drive signals 101S to 103S from the drive circuit 20 to the image sensor 10, two
Since the dimensional image sensor 10 receives the transmitted light of the negative film 2 placed in the printing section through the lens system 11, the two-dimensional image sensor 10 receives the transmitted light from the negative film 2 placed in the printing section.
As shown in Figure A, the entire negative film 2 is divided into a large number of aligned small pixels 21 to form scanning lines.
The entire screen of the negative film 2 can be scanned in order according to the SL. After the entire screen has been scanned, the output register section 1 of the image sensor 10
03, the image signal PS is sampled and held in a sample and hold circuit 21, and the sample value is converted into a digital signal DS in an AD converter 22. The digital signal DS from the AD converter 22 is logarithmically converted by the logarithmic conversion circuit 23 to obtain a density circuit DN, and this density signal DN is controlled by the write control circuit 24.
The density digital values of the negative film 2 are stored in the memory 25 in an arrangement corresponding to the pixels 21 as shown in FIG. 4B.

In this way, the negative film 2 is stored in the memory 25.
When digital values for each pixel or density values for each pixel related to the three primary colors are stored, the negative film 2
Digital values can be read out from the memory 25 and used for each pixel. Therefore, the three primary colors
If density values such as those shown in Figure 4B are determined and stored for each RGB, the exposure correction amount can be read out and processed by calculation, etc., for each RGB, in the same way as with conventional scanners for reading film image density. can be determined. Conventional film measurement scanners are designed to determine the photoprinting exposure amount and exposure correction amount, but in the present invention, the photoprinting exposure amount is determined by the optical sensor 8.
Only the exposure correction amount is determined using the two-dimensional image sensor 10. Compared to determining the exposure amount using LATD, photometry for determining the amount of exposure correction, which corrects the subdivision area for the exposure amount, does not require as wide a dynamic range as LATD photometry, and also has less photometric accuracy. It was found that it can be used even if it is about one order of magnitude lower. From this, it has become possible to use the two-dimensional image sensor 10 by using it only for determining the amount of exposure correction. The exposure correction amount can be determined, for example, according to Japanese Patent Application Laid-Open No.
The methods disclosed in Japanese Patent Application Laid-open No. 23936 and Japanese Patent Application Laid-Open No. 54-28131 can be used. In this way, the drawbacks of conventional two-dimensional image sensors have been solved, and the photo printing device has been developed as a scanner with many features such as its small size, low price, simple structure, and low failure rate due to the lack of moving parts. This is what was used for.

Next, an example of a method for determining the image frame size of the negative film 2 will be described as an example of image information obtained from photometric data.

Here, the long negative film 2 is guided by the negative carrier 1 and sequentially conveyed to the printing section.
In the baking section, as shown in FIG. 5, a rectangular upper guide 1B having an opening 1A engages with a lower guide 1C disposed below, and is held between the upper guide 1B and the lower guide 1C. Negative film 2 held by
is designed to be printed frame by frame. The size of the opening 1A of the upper guide 1B completely corresponds to the frame size of the negative film 2, and the snaking part at the periphery of the frame image protrudes from the edge of the opening 1A of the upper guide 1B. Never. For this reason, the area where the two-dimensional image sensor 10 receives light is designed to include not only the frame images of the negative film 2 but also the non-transmitted light portion of the upper guide 1B so that it can handle large-sized negative films with ease. For example, the image information of the area detected by the two-dimensional image sensor 10 is as shown in FIG. 6A for a 110 size negative carrier, and the image information for a 135F size negative carrier is the same. It will look like Figure B. These figures 6A and B
shows an example of the detected image information of the snake image (base density) when no image is taken on the negative film 2, or an example of the image information when the negative film 2 is not loaded. The part surrounded by the broken line indicates the opening 1A, that is, the area of the image frame. Here, before measuring a film image with a two-dimensional image sensor, the film base on which no image is captured is photometered and stored as a base density or base signal, and the stored value is used when measuring the film image. to remove the base density or base signal from the image density or image signal. As a result, the Snake image (base density) shows a density of 0 as shown in FIGS. 6A and 6B.
Setting the base density to 0 in this way is used to correct variations in the sensitivity of the photometric element, to correct differences in light intensity on the element surface due to diagonal photometry from outside the printing optical path, and to correct two-dimensional images. This is because the sensor's dynamic range is narrow, so unnecessary base concentration must be removed before photometry is performed. Note that it is not necessarily necessary to set the concentration to 0. For example, the base density may be set to 0.2, but in this example, the base density is set to 0 for ease of understanding. Since the size of the image frame corresponds to the size of the negative film 2, the aperture can be determined by detecting the density "0" indicating a snook from the image information read by the image sensor 10 and calculating its area. 1A
As a result, the size of the negative film 2 can be determined. In this case, since the optical axis of the image sensor 10 is directed approximately to the center of the aperture 1A, the number of pixels with a density of "0" (or a value near it) cannot be counted using hardware or software. Thus, the size of the negative film 2 can be determined by comparing the counted value with a predetermined value predetermined for each size.

In this way, from the entire image information read by the image sensor 10, the opening 1A of the negative carrier 1 is determined.
The density "0" area indicating the size of the negative film 2 is calculated based on the number of pixels, and the size of the negative film 2 is determined from the counted value. For example, if the number of pixels with density "0" is 32 (for example, between 30 and 34 to provide a margin) as shown in Figure 6A, then
110 size, as shown in figure B, 160 pieces (for example, between 158 and 162),
In the case of 135F size and 118 to 122 pieces, the size is determined as 126 size. The size determination method is not limited to this example. For example, size information may be automatically output from a lens that changes depending on the film size, a negative carrier (negative mask) that changes depending on the film size, etc.

The size information of the negative film 2 determined in this way is sent to the printing system, and after selecting an exposure amount determining formula or calculating it using a predetermined determining formula, printing according to the size is realized.

Here, when determining the exposure amount, the amount of transmitted light of the three RGB color components over the entire area of the screen is usually controlled to a constant value to create a print with a well-balanced color and brightness. This is based on an empirical rule that states that in a normal photographic scene, the average spectral reflectance of three colors, which is obtained by integrating the spectral reflectance of many scenes, is approximately constant. In other words, when you photograph a general medieval subject with color negative film, the average transmission density depends on the amount of exposure, the quality of the light source at the time of photography, the sensitivity of the RGB photosensitive layer of the color negative film,
Although it changes depending on the presence or absence of a mask, etc., these changes can be controlled by keeping the RGB printing exposure constant during printing.

On the other hand, changes in the density of the three colors of the color negative film that occur due to the uneven color distribution of the subject cannot be controlled correctly using the above method because it changes the area component ratio of the three colors of the subject. (colorful area). Also, if the brightness composition is extremely biased compared to the normal brightness distribution, such as when there are extremely many high brightness areas or low brightness areas compared to a normal scene, the density change of the negative film will be Since this is due to areal changes in the density of the object, it cannot be corrected by controlling the printing exposure amount only based on the average transmitted density. Similarly, if the main subject forms a shadow area or an extreme highlight area compared to the surrounding subjects, it cannot be corrected because it differs greatly from the printer setting conditions (these are referred to as dense areas). The color area and density area are collectively called the subdivision area. As a method for determining the printing exposure amount to solve such problems, Japanese Patent Application Laid-Open No. 52-23936
No., Japanese Patent Publication No. 54-28131, and Japanese Patent Publication No. 56-2691, the negative screen is divided into many parts and photometered to obtain the image density, and the maximum density and minimum density are calculated from the obtained many image densities. There is a method of obtaining characteristic values of a film image, such as the average density of various divided screens, and determining an appropriate exposure amount for the scene in question. For example, if the characteristic values of a film image are the average transmitted density of the screen as Da, the maximum density on the screen as _Dnax , and the minimum density as _Dnio , then for example, the exposure amount for a 135F size film.
_{X 1 is expressed as _ _ _ _ _ _ _} It is expressed as _a + b ₂・D _nax + c ₂・D _nio + D ₂ ...(2). Here, a ₁ , b ₁ , c ₁ , a ₂ , b ₂ , and c ₂ are coefficients, and D ₁ and D ₂ are constants. For the exposure amount X obtained in this way, if you prepare a correction formula (3) for each film size, such as K _s = K _i + K _j · The negative film 2 can be printed with the correctly corrected exposure amount _Xs . Here, the coefficient K _i ,
K _j can be determined experimentally depending on the film size.

However, in the above example, it is necessary to create the exposure calculation formulas (1), (2), etc. for each film size, which is extremely difficult to create. The reason why an exposure calculation formula must be created for each film size is that the same image characteristic values cannot be obtained from film images of different sizes taken of the same subject. This is because the photometric pixel size is not proportional to the film size. Therefore, it is sufficient to use pixels for which image characteristic values are calculated as proportional to the film size as possible based on the film size information.

According to the present invention, photometric pixels are combined to form divided areas (new pixels for creating characteristic values) according to film size information, and the average density thereof is used to create characteristic values of the film image. All divided regions may be composed of the same number of pixels (combined), or may be composed of any number of pixels as necessary. Since the divided areas are the minimum areas for determining image characteristic values, they can be said to be pixels for creating characteristic values for each film size. For example, to measure the maximum density and minimum density, the minimum divided area is the minimum divided area corresponding to the film size, but if the upper half of the screen is to be used as the pixel characteristic value, the divided area in the upper half of the screen may be determined. .

Next, the divided regions shown in FIGS. 7A and 7B will be explained. 2D image sensor 1 from negative film 2
The size of the pixel PX itself measured at 0 is constant for each size, and the divided area, which is the minimum unit to create the characteristic value of the film image, is shown in Figure A.
135F size has 4 rows of pixels C1A to C4A
and pixels R1A to R4A in the 2nd column, 3rd column, 3rd column, and 2nd column
The screen is divided into 16 areas, and the data at the center of the screen is
It is obtained from the central area CPA of 16 pixels.
In addition, in the 135H size shown in 7th B, the screen is divided into 16 areas by pixels C1B to C4B in 2 rows and pixels R1B to R4B in 2nd column, 3rd column, 3rd column, and 2nd column, and the screen center data is 16 Obtained from the central area CPB of the pixel.

Even if the film size is different, the number of divided areas and the position of the divided screen are in one-to-one correspondence, and by determining the divided area size corresponding to the film size, the image characteristics from the film image of the same subject can be improved even if the film size is different. Approximate values can be obtained, and a common exposure determination formula can be used for each size. For example, the above equations (1) and (2) are calculated using the average transmission density created from the 16 divided areas in Figure 7.
From D _a , maximum density D _nax and minimum density D _nio , the following formula (4) can be used in common for both 135F size and 110 size films.

X=a・D _a +b・D _nax +c・D _nio +D ...(4) The present invention is by no means limited to the formula (4); for example, JP-A-52-23936, JP-A-54- 28131
Arithmetic expressions such as numbers can also be used in the same way. Note that the above-mentioned exposure calculation formula includes an exposure correction amount calculation formula, and similar formulas can be used.

In the 126 size shown in Fig. 7C, the screen is divided into 16 regions with pixels C1C to C4C in 3 rows and pixels R1C to R4C in 2nd, 3rd, 3rd, and 2nd columns, and the screen center data consists of 16 pixels. Obtained from the central area CPC.
Similarly, in the 110 size of FIG. 7D, pixels C1D to C4D are arranged in two rows and pixels R1D to R4 are arranged in one column.
D divides the screen into 16 parts, and 4 pixels form the central area CPD, and in the disk size of E in the same figure, pixels C1E to C4 in 2nd row, 1st row, 1st row, and 2nd row.
E and pixels R1E to R4E in each column divide the entire pixel into 16, and the central area is divided into 4 pixels.
Forming CPE. In this way, for each film size, the screen is divided into 16 areas E1~
If the image characteristic values are obtained using E16, image processing can be performed using a common procedure even if the film sizes are different. In the example of Figure 7 D and E,
The divided areas E1 to E are sufficiently proportional to the film size.
6 is not changed, but the size of the areas E1 to E6 does not change compared to the 135F size, and the exposure amount can be obtained with higher accuracy. Therefore, it is effective even for film sizes of this size. Since a two-dimensional image sensor has tens of thousands of pixels, for example, by setting C1A to 12 and R1A to 8, the 7th
Figures D and E also have C1D and R proportional to the film size.
1D, C1E, and R1E can be determined.

Here, the number of divided areas for each size is 16, but it can be divided into any number (for example, 20, 30), and it can be divided into as many pixels as possible, for example, proportional to each film size. Areas can be associated. There is also a method of combining photometric pixels to find the pixel density of each divided area.
All pixel data may be once stored in the memory and then read out and processed, or the pixel data may be processed in parallel with the detection of the pixel data according to size information obtained in advance. Furthermore, even if the present invention is not applicable to all film sizes, it includes application to at least two different film sizes. For example, it is possible to use the present invention by attaching two simple lenses so that they can be switched between the Browni size and the 135F size, and applying the present invention between the various Browni sizes and between the 126 size and the disk size. .

In the above-described embodiment, the two-dimensional image sensor 10 is installed at an angle with respect to the optical axis LS of the negative film 2 and the light source 4; The light may be reflected by an arranged half mirror and the reflected light may be provided to the two-dimensional image sensor 10. in this case,
The light transmitted through the half mirror passes through the lens system 5 and is irradiated onto the photographic paper 7. In addition, the optical axis of the range system 5 and the two-dimensional image sensor 10 can be mechanically adjusted.
The mechanism is movable to the LS, and when printing the negative film 2 on the photographic paper 7, the lens system 5 is moved to the optical axis.
The two-dimensional image sensor 10 may be made to coincide with the optical axis LS when the size is determined by detecting the image information of the negative film 2. Further, in the above description, image information is detected from the transmitted light of the negative film 2 using the two-dimensional image 10, but it is also possible to detect the image information by applying the reflected light of the negative film 2 to the two-dimensional image sensor. be.

Furthermore, the number of elements of the above-mentioned image sensor is arbitrary, and can be selected from the size of the original film such as a negative film, the magnification of the lens system, the required number of pixels of the screen, etc.

(Effects of the invention) By performing LATD photometry using an optical sensor and photometry by dividing a film image into a large number of pixels using a charge accumulation type two-dimensional image sensor such as a CCD,
It can be effectively used for photographic film photometry of a two-dimensional image sensor, and enables compact and simple photometry. Such a two-dimensional image sensor enables photometry of various film sizes with one photometry device. In particular, by using the film size information, data corresponding to the film size can be combined into division information, making it possible to use the same exposure amount determination formula and exposure correction formula even if the film sizes are different. This has the effect of making it possible to determine the exposure amount for each film size without using a zoom lens or the like, or by simply exchanging lenses, in a compact, low-cost, simple, and highly accurate manner.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the application of the present invention to a photo printing device, Fig. 2 is a block diagram showing the functions of a two-dimensional image sensor used in the present invention, and Fig. 3 is a two-dimensional image of the present invention. 4A and 4B are diagrams illustrating an example of the correspondence between pixel division of an original film and stored data according to the present invention; FIG. 5 is a diagram showing details of the printing section; FIG. , FIGS. 6A and 6B are memory diagrams showing examples of image information of the present invention, and FIGS. 7A to E
1 is a diagram showing an example of divided regions (new pixels for creating characteristic values) for various films. 1...Negative carrier, 2...Negative film, 3
... Filter, 4 ... Light source, 5, 11 ... Lens system, 6 ... Black shutter, 7 ... Photographic paper, 8 ... Light sensor, 10 ... Two-dimensional image sensor, 20 ... Drive circuit, 22 ...AD converter,
24...Write control circuit, 25...Memory.

Claims (1)

[Scope of Claims] 1. Photometric means for dividing a film image into a large number of pixels and measuring the light; Logarithmic conversion means for converting the photometric value into a density value; and Arranging the pixels in the pixel for converting the density value of each pixel a memory means for storing data according to the film screen size; a size determining means for determining the film screen size; and according to the screen size, the positions of the divided regions correspond one-to-one regardless of the film size, and the size is approximately the same over the entire screen. pixel compositing means for forming composite pixels by dividing the entire area of the film image into a predetermined number of divisions so that the image information such as screen center density, maximum density, etc. an image information creation means for determining the image information, and an exposure amount determination method for determining the exposure amount based on a predetermined exposure amount determination formula that is common regardless of the screen size, using the image information of the composite pixel obtained by the image information creation means. 1. A photographic printing exposure amount determination device comprising: means.