JPH0355536A - Photographic printing method - Google Patents

Abstract

PURPOSE:To perform high-accuracy exposure control by recording brightness information on an object at the time of photographing, reading the brightness information at the time of photographic printing and classifying scenes according to the brightness information, and calculating a printing exposure quantity for each photographic scene. CONSTITUTION:The brightness information on the object is recorded at the time of the photographing, the brightness information is read out at the time of the photographic printing to classify scenes, and a printing exposure quantity is calculated for each photographic scene by using an arithmetic system such as a prepared arithmetic expression. Namely, a photometric value of the light of the object is controlled by a shutter mechanism 12 and sent as the brightness information to a bar code data generating circuit 23, and converted into bar code data, which is recorded on, for example, a film 18. The brightness of the bar code data is predicted by using the brightness information to accurately remove measurement points which are necessary for either the scene classification nor exposure control. Consequently, the high-accuracy exposure control is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photographic printing method, and more particularly to a photographic printing method that utilizes brightness information of a subject to determine the printing exposure amount.

[Conventional technology]

In photographic printing, the entire frame recorded on the photographic film is photometered to determine the average density of the three primary colors (red, green, and blue), and the printing exposure of the three colors is adjusted according to these average densities. There is. This exposure control is called the LATD method, and determines the printing exposure amount for each color so that the integrated three primary colors of a printed photograph are finished in gray. Also, L.A. The TD method classifies shooting scenes using characteristic values such as maximum density and minimum density, and creates a set of values for each shooting scene, since the main subject cannot be properly finished in shooting scenes with uneven density or color. Some methods are known in which the amount of correction is calculated using an arithmetic expression and the basic exposure amount determined by the LATD method is corrected.

[Invention tries to solve it! ! ! ! [Problem] A camera is equipped with a shutter and an aperture, which are controlled according to the brightness information of the subject to record the subject on photographic film at an appropriate density. For this reason, it is not possible to accurately identify whether the image was taken at night, in the evening, during the day, or indoors or outdoors, based on the density of the image recorded on the photographic film.

For example, a sunset shooting scene is determined to be a backlit shooting scene,
As a result, it was not possible to reproduce the sunset conditions. Furthermore, since it is not possible to distinguish between fireworks shooting scenes and underexposed scenes, fireworks shooting scenes cannot be properly printed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photographic printing method that can highly accurately remove portions unnecessary for photographic scene classification and exposure control.

[Means to solve the problem]

In order to achieve the above object, the present invention records the brightness information of the subject when taking a photo, reads the brightness information when printing the photo, performs scene classification based on this brightness information, and stores data prepared for each shooting scene. The printing exposure amount is calculated using arithmetic methods such as the following arithmetic formulas. Here, the brightness information represents the brightness of the subject, and may include subject brightness, photographic brightness, brightness value, light value, etc., and may also be information representing the rank of these sizes. Further, the brightness information is measured by average photometry, spot photometry, area division photometry, multi-point photometry using an image sensor, or the like.

Another invention records the average brightness information of the subject when taking a photo, measures each point on the screen when printing the photo, converts the photometric value of each point into brightness information by considering the average brightness information, and calculates the brightness of the subject. Those whose information is within a certain range are taken out as effective measurement points, and characteristic values used in calculating the printing exposure amount are extracted from the photometric values of these effective measurement points.

Another invention records the average brightness information of the subject when taking a photo, measures each point on the screen when printing the photo, and converts the photometric value of each point into brightness information by taking the average brightness information into consideration. Scene classification is performed based on the magnitude of the maximum value of the brightness information obtained, and the printing exposure amount is calculated using an arithmetic method such as an arithmetic expression prepared for each photographic scene.

[Effect]

The subject is photometered by average photometry, spot photometry, etc., and the obtained luminance information is recorded on, for example, a photographic film. This brightness information is used for scene classification and for extracting valid measurement points.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a camera that records luminance information.

The photographic lens 10 is composed of an optical system 10a and a lens barrel lOb that holds the optical system 10a, and is moved back and forth along the optical axis 11 manually or by an autofocus mechanism to adjust the focus.

A shutter mechanism 12 is arranged behind the photographic lens 10. The shutter mechanism 12 is composed of, for example, two shutter blades fI13, 14, and each shutter blade 13,14 has a cutout 3a, 14a, respectively. When the movable bin l6 is moved toward the fixed bin 17 by the driving vJ mechanism 15, these shutter blades 13, 14 move away from the fixed bin l7 to overlap the notches 13a and 14a. A portion where the notches 13a and 14a overlap is opened, and light passing through the opening is incident on the photographic film 18, and the subject is imaged thereon.

A sensor 21 is placed behind the lens 20 to measure the brightness of the subject. The output signal of this sensor 21 is sent to a calculation circuit 22, where it is calculated together with the film sensitivity to calculate a light value (L■). This light value is sent to the driver side 15 to program control the shutter mechanism 12 in a known manner. Further, this future value is sent as luminance information to the barcode data generation circuit 23, where it is converted into barcode data. The driver 24 drives the barcode recording device 25 to record the luminance information represented by the barcode on the photographic film l8. The barcode recording device 25 of this embodiment is composed of a liquid crystal display 26 for displaying barcodes and a flash discharge tube 27 for illuminating the display. Imprint brightness information between
FIG. 2 shows a photographic film on which luminance information is recorded. This photographic film l8 is perforated with perforations 18b at regular intervals, and when the perforations 18b are detected by the sensor of the I stopper 1, one frame advance is performed. Burforation 18b
Luminance information 30 represented by a barcode is imprinted on the opposite side of the image, and is converted into a visible image by photo development.

Note that the brightness information 30 includes symbols, numbers, etc. in addition to barcodes. Characters etc. can be used. Alternatively, a mark recorded with a light emitting diode or the like may be used and the mark may be shifted from the reference position depending on the brightness and recorded.

FIG. 3 shows a photo printer. The white light emitted from the light source 35 is passed through a cyan filter 36 . After passing through a magenta filter 37 and a yellow filter 38, it enters a mixing box 39.

The amount of insertion of these color correction filters 36 to 38 into the optical path 4l is adjusted by a filter adjustment section 40, thereby adjusting the amount of the three colors of the printing light and their intensity. The mixing box 39 is a rectangular box whose inner surface is a mirror surface, with diffusion plates attached to both ends thereof.

A film carrier 43 is placed at a print position, a developed photographic film 18 is set therein, and the film carrier 43 is illuminated with light transmitted through a four-way printing box 39. In order to ensure the flatness of this photographic film 18, a film mask 44 is provided above the printing position. As is well known, this film mask 44 has an opening corresponding to the size of the frame, and when transporting the photographic film 18,
It is lifted up by a solenoid (not shown) and presses down the photographic film 18 during printing.

A barcode reader 45 is placed in front of the print position, and when the photographic film 18 is sent to the print position, the brightness information 30 recorded on each frame is read. This read luminance information is decoded by the decoder 46 and then sent to the calculation section 47.

Further, diagonally above the printing position, there is a scanner 5 which is composed of a lens 48 and an image area sensor 49.
0 is placed, and the transmitted light at each point of the frame set at the print position is measured.

The signal from the scanner 50 is sent to a signal processing circuit 51, where it is subjected to logarithmic conversion and digital conversion, and then the density signal at each point is sent to the calculation section 47.

The controller 52 sets the set positions of the color correction filters 36 to 38 to U8 according to the printing exposure amounts of the three colors calculated by the calculation unit 47. Further, the controller 52 controls not only the filter adjustment section 40 but also various sections such as the shutter drive section 53 and the like.

A printing lens 56 is disposed above the print position, and enlarges and projects the image of the set frame onto color paper 58 disposed behind a paper mask 57. A shutter 59 whose opening and closing are controlled by a shutter drive section 53 is provided between the printing lens 56 and the color paper 58.
is located.

Figure 4 shows the functions of the calculation section. Memo +7 6
2 stores the three-color densities of each measurement point photometered by the scanner 50, and the three-color densities are sent to feature value extraction units 63 and 64 when calculating the printing exposure amount. The feature value extraction unit 63 is an L.A. Basic exposure amount EB based on TD method
The feature value used to calculate i (i represents any one of red, green, or blue) is extracted and sent to the calculation unit 66. Further, the feature value extraction unit 64 extracts feature values for calculating the corrected value ΔE.

The decoder 65 switches the selector 67 according to the luminance information, and selects one of the two calculation units 68 and 69 to be used for calculation of the correction amount. The correction amount ΔE calculated by the selected calculation unit is sent to the printing exposure calculation unit 70, which corrects the basic exposure amount EBi with the correction amount ΔE to obtain the printing exposure amount E.
is calculated and sent to the controller 52. A plurality of correction amount calculation formulas are prepared and are selected depending on the luminance information. Film sensitivity is ■S0 100 (
7) Sometimes, when the light value (LV) is 12 Mt, there are many backlit or snowy scenes, and in such scenes it is better to greatly reduce the printing exposure amount. LV is 7-1
In No. 2, there are many scenes photographed against white walls, etc., and in this case, it is better to reduce the printing exposure amount to some extent. LV is 7
If the value is less than 1, the photographic scene is indoors, at sunset, or at night, so it is better to increase the printing exposure amount to some extent. Therefore, in this embodiment, different correction amount calculation formulas are used to calculate the correction amount when the LV is 7 to 12 and when it exceeds 12, and the basic exposure amount is corrected using the correction amount. Examples of these correction amount calculation formulas are shown below.

(1) 7 ≦L V ≦1 2 ΔE=Ko +KI D)4AX +K2 DMIN+
K3DM ・ ・ ・(1)(2)LV>1
2 ΔE = K +. 10K, DMA, +K, 2D. ,N
+ K , :l DM + K Ia D c +
K Is DL・・・・(2) Here, each symbol is as follows.

D MAX ... Maximum value of gray density in the screen 0
1118 ...Minimum value D of gray density within the screen
n...Average gray density of the screen D,...
・Average gray density DL in the center of the screen shown in FIG. 5(A) ... Gray density is used as a characteristic value for the average gray density in the lower half of the screen shown in FIG. 5(B), but this gray The density is determined, for example, by the arithmetic mean of the three color densities. Further, the following numerical values are used as the coefficients K0 to KIS.

K0...-4.26? 1 ・ ・ ・ ・ 0.03 K2 ・ ・ ・ ・ 0. 02K3 ・ ・
・ ・ 10. 06K,.・ ・ ・ ・ −
1. 20Kl1 ・ ・ ・ 0. 02
K1■・ ・ ・ ・ 0, 06Kl3・ ・
・ ・ 10. 1 4K.・ ・ ・ ・ 0
．． 03 KIs・ ・ ・ ・ 0. 03 The basic exposure amount is calculated using characteristic values in a wide range such as LATD, for example, the average density, and there is the following equation using the characteristic value D.

已B. - α1 ・ (Di-DN5) + β. ...
・(3) Here, each symbol is as follows.

α...Slope coefficient β...Constant DN determined by the combination of photographic film, color paper, printing lens, etc....Average density of control negative D...Average density of frames to be printed Basic exposure amount EB, Correction amount Δ
Correct with E to determine the optimal printing exposure amount E. However, when the first step of the density correction key is 20% of the exposure amount, the following equation is used.

Next, the operation of the above embodiment will be explained. When taking a photograph, after determining the composition by pointing the camera at the main subject and pressing the release button halfway down as is well known, a signal of the subject brightness measured by the sensor 2l is sent to the arithmetic circuit 22.

The arithmetic circuit 22 calculates a light value (LV) from the subject brightness and film sensitivity, and sends it to the barcode data generation circuit 23 and the drive mechanism 15. When the release button is further pressed, the drive mechanism 15 reciprocates the drive pin l6 by a stroke corresponding to the amount of light, opens and closes the shutter mechanism 12, and takes a picture.

Simultaneously with or before or after taking this photograph, the barcode data generation circuit 23 converts the light value used as brightness information into a barcode and sends it to the driver 24. This driver 24 drives the barcode recording device 25 and first displays the luminance information of the parcode on the liquid crystal display 26. When this display becomes stable, the flash discharge tube 26 is made to emit light, and the luminance information 30 is imprinted on the periphery of the screen 18a as shown in FIG.

When the photographing of one photo film 18 is completed, the photo film 18 is taken out from the camera and submitted to a photo processing laboratory. At the photo development laboratory, the photographic film 18 is developed to convert each frame recorded as a latent image and the luminance information recorded for each frame into a visible image.

The developed photographic film 18 is loaded into a film carrier 43 of a photographic printer shown in FIG. 3, and a frame to be printed, for example 18a, is set at a printing position. Immediately before this frame 18a is transported toward the printing position, a barcode reader 45 reads the luminance information 30 recorded on the periphery of the frame 18a. This read luminance information is decoded by the decoder 45 and then sent to the calculation section 47. Ru.

When the frame 18a is set at the print position, the scanner 50 measures red, green, and blue transmitted light at each point on the frame 18a. The photometric values of these three colors are converted into densities by the signal processing circuit 51 and then sent to the calculation section 47. This calculation unit 47 calculates the characteristic value D from the three-color density of each point.
■×+ D'HIN, DJ1, etc. are each extracted and substituted into the correction amount calculation formula selected according to the luminance information to calculate the correction amount ΔE. The calculation unit 47 also calculates the average density D of the entire screen. is calculated and substituted into the arithmetic expression (3) to calculate the basic exposure 31EBi. Next, the calculation unit 47 calculates a printing exposure amount E table for each color by substituting the basic exposure i1EBi and the correction amount ΔE into the calculation formula (4), and sends this to the controller 52. This controller 1/roller 52 controls the optical path 41 of the color correction filters 36 to 38 according to the printing exposure IEi.
The amount of insertion into the tPI clause. After this filter adjustment, the shutter 59 is opened for a certain period of time, and the frame 18a is printed and exposed on the color paper 58.

Thereafter, each frame of the photographic film 18 is sequentially printed and exposed in the same manner.

In the above embodiment, scene division is performed from luminance information, but
Luminance information may be used to select measurement points (pixels). First, the screen is photometered to determine the gray density DJ (j represents the position) at each point, and this is stored in memory. From the gray density Dj of each point, the average gray density D. The difference ΔD is calculated from these two gray densities Dj+DM.

ΔDJ=D, -D. This difference ΔD. and the light value LV determined by average photometry of the subject and recorded on the photographic film are substituted into the following equation (5) to predict the light value LV at each measurement point.

In this way, the brightness of the photographed scene is predicted from the image density, and parts with unnecessary brightness for exposure control, such as extremely bright parts such as the sky and snow, are removed and feature values are extracted from the remaining parts. .

For example, when using photographic film with ISO 100, is it effective to measure the light value LV of 15 or less? The correction amount ΔE is calculated by substituting the density D of these effective measurement points into the correction amount calculation formula (6).

ΔE = K t o + K t ID M^x +
KxzDl4+N+Kt3Dw +Kz4Dc +Kz
sDt+KzaDv +KztDi++KzaDtt・
...(6) Here, each symbol is as follows.

D, ...Average gray density D■ at the top of the screen shown in Figure 5 (B) ...Average gray density 1)ti at the right half of the screen shown in Figure 5 (C) ...5th For example, the following values are used as coefficients for the average gray density of the left half of the screen shown in Figure (C). .

K2.・ ・ K.・ ・ K2■・・ Kt3・・ Kza・・ 0. 40 0. 04 0. 02 -0.10 0. 03Kt%” ・ ・ ・ 0.03Ko・ ・ ・
・ -0.03 K2, ・ ・ ・ 0. 02K0・ ・ ・
-0.03 Also, the maximum value (LVJ) of the reproduced light values (LVJ) at each point
It is also possible to classify the scenes based on the size of LVMAx) and calculate the correction amount using a correction amount calculation formula prepared for each shooting scene. (1) When LVxax≧15, ΔE=Kso+K*tDkenκ+K'lgl)l4+11
10KaaDw +K34DC +K*aDt+K3&D
LE (7) For example, the following numerical values are used as coefficients of this arithmetic expression (7).

K. ... -1.69 K. ... 0.02 Ko... 0.03 K33... 10. 14 K3m... 0.04 K31... 0.06 K36... ・ ・ ・ -0. 03(2) LV
MAX<15cD tkΔE = K3(++ K31
DMAX + K3gDx+x 10KszI) + 10K34DC 10K3SDL 10K,,Du 10K36DL
!・ ・ ・(8) For example, the following numerical values are used as the coefficients of this arithmetic expression (8).

K. ...... 0.24 K31... 0.04 K3t... 0.03 K33... -0.09 K3a... 0.04 K3%... 0.03 K3l ,... -06 03 K'l? ...10,04 The above embodiment uses the correction amount calculation 2 for density correction, but the present invention can also be applied to density correction and color correction by chest pattern recognition etc. be. Furthermore, brightness information may be used to determine the basic exposure amount. Furthermore, instead of recording the luminance information on the photographic film, it may be recorded on another recording medium, such as an IC card or a magnetic recording section formed on the outer periphery of the batrone, or a recording medium connected to the film. You can. Furthermore, the present invention can also be used when printing images recorded with an electronic still camera. In this electronic still camera, brightness information is written to a magnetic floppy along with image data. For example, when an image is displayed on a CRT and recorded on color paper by a digital color printer, the brightness information of this image is read out and used to control the exposure amount of each point based on the image data.

In addition to average photometry, the brightness information may be spot photometry, multi-point photometry using an image sensor, or divided photometry that divides the area into a plurality of areas. In the case of multi-point photometry, since the brightness information of each point is recorded, it can be used as is, and in the case of divided photometry, the brightness information of the corresponding area is used. Furthermore, in the autofocus camera, the position of the main subject to be measured may be recorded, and the scene may be classified based on the brightness of the main subject, or effective measurement points may be extracted.

〔Effect of the invention〕

The present invention having the above structure predicts the brightness of a subject using the brightness information recorded during photography, and therefore accurately removes measurement points that are unnecessary for scene classification or exposure control. This makes it possible to achieve highly accurate exposure control.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a photographic camera that records brightness information of a subject. FIG. 2 is a plan view of a photographic film showing an example of recording luminance information. FIG. 3 is a schematic diagram showing an example of a photographic printer embodying the present invention. FIG. 4 is a functional block diagram showing an example of a calculation section that calculates the printing exposure amount. FIG. 5 is an explanatory diagram showing the relationship between feature values and their extraction areas. 1 0 ・ 25 ・ l 8 ・ 3 0 ・ 45 ・ 50 ・ ・Photographing lens, barcode recording device, photographic film, brightness information, barcode league, scanner Figure 4 (C)

Claims (3)

[Claims] (1) Record the brightness information of the subject when taking a photo, read the brightness information when printing the photo, classify the scene based on this brightness information, and calculate the printing exposure using a calculation method prepared for each shooting scene. A photo printing method characterized by calculating. (2) Record the average brightness information of the subject when taking a photo, measure each point on the screen when printing the photo, take the average brightness information into consideration, and convert the photometric value of each point into brightness information. A photo printing method characterized in that points within a certain range are taken as effective measurement points, and characteristic values used for calculating printing exposure are extracted from photometric values of these effective measurement points. (3) Record the average brightness information of the subject when taking a photo, measure each point on the screen when printing the photo, and convert the photometric value of each point into brightness information by taking the average brightness information into consideration. A photographic printing method characterized in that scenes are classified based on the magnitude of the maximum value of luminance information, and a printing exposure amount is calculated using a calculation method prepared for each photographed scene.