JPH06138539A - Recorder for camera - Google Patents

Abstract

PURPOSE:To prevent discoloring phenomenon even in the case that a specified color is apt to enter all over an image plane so that faulty color correction is not performed by detecting information in accordance with the color and the kind of a light source and correcting the detected information in a state where it comes close to the color temperature locus of color information to be recorded and previously prepared light source data. CONSTITUTION:A camera main body 1 communicates with a lens 2, etc., connected to the camera main body 1, and detects a setting condition inside and outside the camera. A recording unit 3 obtains a signal for each condition of the camera through the camera main body 1, and data from the lens 2 is transmitted to unit 3, By receiving a command from the camera main body 1, the value of a color temperature sensor 4 is processed to be recorded by the unit 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device for a camera, and more particularly to a recording device for a camera for recording color data of a light source during photographing.

[0002]

2. Description of the Related Art Generally, when a stall illuminated with a bare light bulb is photographed using a negative color film (generally sold by Delight), a very red image is reproduced as it is. Therefore, when printing on photographic paper, so-called white balance correction is performed to remove reddish color.

However, even with the same bare bulb, the degree of redness varies greatly depending on the driving power supply voltage. In addition, different types of lighting make a greater difference in redness. For example, the light of a candle has a stronger reddish degree than a bare light bulb, and the difference in the light of the sun between daytime and sunset is large. Therefore,
It is necessary to make a correction suitable for each illumination light color.

The determination of the amount of white balance correction is
It is good when the type of lighting is known, but in a normal photo lab, the type of lighting can be identified only within the range shown in the photo, and careful work is performed to identify and process the type of lighting. The reality is that it cannot be done. Therefore, it is common for an operator to judge the degree of redness by observing the tone of a negative film based on experience and intuition or by automatic operation of a printing machine. As a result, the finished product often has an unsatisfactory hue.
Therefore, it has been proposed to provide the color information of the light from the light source taken at the time of photo printing on a negative film, and to reproduce the printing color on the photographic paper based on the data.

As a method of providing color information, a method of imprinting a white color from a photographing light source on a part of a negative film, or a method of digitizing or symbolizing information of the light source and recording it as digital data can be considered. For example, Japanese Patent Laid-Open No. Sho 63-63
Japanese Patent Laid-Open No. 79491 discloses a technique of limiting the range of output values by a colorimetric method in which all color information on the screen is added.

[0006]

By the way, in the method of recording the information of the light source light as digital data and reproducing it at the time of printing to correct the color temperature, as a method of detecting the color temperature of the light source light, a photographing lens is used. There is an “internal light color temperature sensor” that detects a color temperature using light that passes through. When detected with this internal light color temperature sensor, the camera is placed near the window where natural light from the outside comes in, and even when you take a picture of a person on the stage where the light from the bulb hits, the part of the subject you want to shoot is illuminated. The color temperature of the illuminating light source can be detected. Further, even when a color filter or the like is attached to the taking lens, there is an advantage that the color temperature of the light source of the image light beam can be detected. However, on the other hand, it is influenced by the color of the subject, and thus incorrect correction may be applied.

For example, when a forest tree illuminated with sunlight in the daytime is photographed using a negative color film of D-light, the white balance correction is not performed because it is sufficient as it is. However, when the subject is a solid green object, the internal light color temperature sensor detects that the light beam has many green components and determines that it is a light source with a lot of green light, such as a fluorescent lamp. Resulting in. Therefore, the resulting photograph is printed with the green component suppressed, and the so-called fading phenomenon occurs in which the green color becomes lighter.

The present invention has been made in view of the above problems, and the fading phenomenon does not occur even in the case of a close-up of a tree, a forest, or the like, where a constant color is likely to fill the screen.
An object of the present invention is to provide a recording device for a camera that is not affected by the color of a subject and is erroneously corrected.

[0009]

That is, the present invention provides a color detecting means for receiving subject light through a photographing lens and outputting information according to the color of the light source or the type of the light source, and the type of the color or the light source. Information depending on the state of the camera
It is characterized by comprising a correction means for correcting the color temperature locus or the light source data prepared in advance so as to approach it, and a recording means for recording the information corrected by the correction means.

[0010]

In the recording device of the camera of the present invention, even in a scene such as a close-up of a tree or a forest where a certain color is likely to fill the entire surface, information corresponding to the color of the light source or the type of the light source is provided. To be detected. Then, the detected color or the type information of the light source, by making a correction so as to be close to the locus of chromaticity of the recorded color information with respect to the black body radiation, that is, the color temperature locus, or the light source data prepared in advance, Reduce false corrections.

[0011]

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

FIG. 2 shows, as an example of the present invention, a scene showing the relationship between the subject and the camera angle of view when a single-lens reflex camera is used. In the figure, a lens 2 for telephoto is attached to the camera body 1, and the lens 5 is used to photograph a subject 5 such as a coniferous forest.

FIG. 1 is a block diagram showing an example of a communication system of a camera to which the recording device for a camera of the present invention is applied. In the figure, a lens 2 is attached to a camera body 1, and a recording unit 3 for communicating with the camera body 1 to obtain each status signal of the camera is connected. In addition, the recording unit 3 includes a color temperature sensor 4
Is connected, and its value is recorded by a command from the camera body 1.

In such a structure, the camera body 1 communicates with the connected lens 2 and the like to detect the setting state inside and outside the camera. The data of the lens 2 is transmitted to the recording unit 3 through the camera body 1. Then, the recording unit 3 attached to the camera body 1 receives a command from the camera body 1 and processes and records the value of the color temperature sensor 4. The color temperature sensor 4
May be connected to the camera body 1 and send color information of the light source light to the recording unit 4 through the camera body 1.

FIG. 3 is a view showing an arrangement example of the camera body 1, the lens 2 and the color temperature sensor 4. A lens 2 attached to the camera body 1 collects light from a subject to form an image on a film surface (not shown). The light from the lens 2 is bent by the quick return mirror 6 inside the camera body 1 and focused on the focus screen 7 to form an image. The light collected on the focus screen 7
After being reflected by a pentaprism (not shown), it reaches the photographer 10 through the eyepiece lens 9.

The focus screen 7 has a light scattering characteristic as shown in FIG. 4 (b). Therefore, part of the light that has passed through the lens 2 does not pass through the above-mentioned path, and part of the light also travels toward the condenser lens 8. FIG. 4 (a) shows FIG.
FIG. 7 is a diagram schematically showing the optical path of a so-called finder section after the focus screen 7 of FIG.

FIG. 5 is a diagram showing the configuration of the color sensor 4. The light collected by the condenser lens 8 shown in FIG. 3 hits the milky white diffuser plate 11 of the color sensor 4 and is diffused. Then, the light reaches the respective light receiving sensors 13 on which the color filters 12 of the respective colors of red (r), green (g) and blue (b) are mounted.

The electric circuit after the light receiving sensor 13 is shown in FIG.
Shown in (a) and (b). Photodiode (PD
i) 14 is a main part of the light receiving sensor 13. When the photodiode 14 is exposed to light, a potential difference is generated across the photodiode 14. An operational amplifier (OP.AM) is provided via a logarithmic compression diode (Di) 15 so as to cancel the potential difference.
P) The electron is taken out by the action of 16. The number of electrons taken out is proportional to the intensity of light hitting the photodiode 14, and the current taken out and the voltage change on the anode side of the logarithmic compression diode 15 have a logarithmic relationship.

The resistors 17 (R1), 19 (R2),
Capacitor (C1) 18, operational amplifier (OP.AMP)
Reference numeral 20 constitutes an amplifier circuit in which the sensitivity of the human eye is changed for each offset R, G, B in order to take into consideration that green is strong and red and blue are weak. This amplifier circuit has a capacitor 18
Since a high band cut filter with a resistor 19 and a resistor 19 is attached, noise components are removed, and only the optical signal component passes (cuts are made at portions higher than the light quantity change frequency of the fluorescent lamp, including the inverter type). .

Further, as shown in FIG. 6 (b), the R, G, and B pass through an amplifier circuit composed of resistors 21 and 22, an operational amplifier 23, and a logarithmic expansion circuit of a transistor 24 and a resistor 25, It is input to the CPU 29 via the resistors 26 and 27 and the amplifier circuit of the operational amplifier 28. R, G, B above
Is a linear value because it is logarithmically compressed and then logarithmically expanded when a CPU is detected.

As shown in FIG. 4A, the light which forms an image on the focusing screen 7 by the lens 2 is as shown in FIG.
The light is scattered by the scattering characteristic shown in (b), and a part thereof is collected by the condenser lens 8 and detected by the color temperature sensor 4. Then, the light collected by the color temperature sensor 4 is eliminated by the milky white diffusion plate 11 provided in the color temperature sensor 4 depending on the position of the image, and is selected by the color filter 12 for each wavelength component of r, g, and b. After being processed, each light receiving sensor 13 detects the light. The detected light intensity signals of the respective colors are logarithmically compressed by the circuit shown in FIG. 6, amplified by an offset according to the relative luminous efficiency, and further input to the CPU 29 as color signals R, G, B of the light source light. To be done.

The above is the description of the hardware portion up to the detection of the color signal of the light source light. The state of the camera is a state in which the illuminance of the shooting scene is bright, a state in which there is a periodic flicker in the light beam to be shot,
A state in which it is detected that the subject to be photographed is distant, a state in which it is detected as a photographing lens, a state in which the photographing lens is a macro lens or photographing a narrow range, or a color sensor is generally used. There is a state where it is detected that the value is extremely far from the value of the typical light source. Then, for example, the illuminance serving as a criterion for indicating a bright case is about 1000 Lx, the detection criterion for being far away is about 5 m, and the detection criterion for being a telephoto lens has a focal length of about 150 mm.
Is. Next, with reference to the flow charts of FIGS. 7 to 10, a part of software for processing the detected color into a value to be actually recorded will be described.

First, the value represented by the relational expression of the equation 1 excluding the change in the luminance of the light source of the color signals R, G, B (due to flicker, etc.) and the size of the flicker ΔR, ΔG, ΔB are expressed as Obtain (step ST1). The value of this relational expression and ΔR
The subroutine for obtaining .DELTA.G and .DELTA.B is shown in FIG.

[0024]

[Equation 1]

The value of the relational expression of Equation 1 and ΔR · ΔG · Δ
In the B detection subroutine, after R, G, and B are A / D converted (step ST41), 1 is added to the counter value (step ST42). Then, the minimum value and the maximum value are entered in the respective values of R, G, B (step ST4).
3). When the A / D conversion of R / G / B is completed (step ST44), the process stands by for a predetermined time (step ST4).
5). This step ST45 eliminates periodic flicker.
This is for detecting a small number of times by detecting the periodicity.

Then, regarding the above-mentioned R, G, B, again A /
The D conversion is started (step ST46), and R, G, and B are added to the values of the relational expression of the above mathematical expression 1 (step ST47). Thereafter, the minimum and maximum values of R, G, and B are compared with R, G, and B (step ST48-
ST59), the difference ΔR, ΔG, ΔB between the maximum value and the minimum value is obtained (step ST60).

When the above process is completed, the counter is incremented (step ST61), and the value of this counter is judged (step ST62). Then, in this case, if the above-described processing operation is repeated 100 times, this subroutine is exited. In this subroutine, the total flow is 100 times, and R.
G and B are measured, the total is taken as the value of the relational expression of the above mathematical expression 1, and the difference between the maximum value and the minimum value is taken as ΔR · ΔG · ΔB.

Returning to the flowchart of FIG. 7, T indicating the degree of incorrectness, that is, the degree of error is cleared to 0 (step ST2). Then, the values of the relational expression of the above mathematical expression 1 are summed to obtain Y indicating the brightness (step ST3). After that, if the illuminance of the subject is bright, it is considered that the subject is shooting outside using the constant C _1, and there is a possibility that all the colors are green. Therefore, the probability that the colorimetric value is correct is low, and the value of T is set high. (Steps ST4 and ST5). Since the possibility of natural light is high even if it is not all green, there is no problem even if it approaches the color temperature locus.

Here, if the flicker of the light source is small, it is considered that the image is taken outdoors because it is taken with natural light, and there is a possibility that there are many greens such as plants, so the correct probability is low, and T
Is set to a high value (steps ST6 to ST9). Although the color temperature of the light rays is not taken into consideration here, the correct probability may be lowered when there is no flicker and the color temperature is close to daylight color.

Further, when the focal length of the taking lens 2 is long, the range of the object detected by the color temperature sensor 4 is narrow, so that there is a high possibility that wrong colorimetry will be performed, and the value of T is set to a high value. (Steps ST10 to ST12).
Then, the distance to the subject is obtained from the amount of extension of the lens when the subject is in focus. Here, when the distance to the subject is long, it is considered to be outdoor photography, and there is a possibility that there are many greens such as plants, so the correct probability is low, and the value of T is set high (steps ST13 to ST).
15).

Next, a predetermined constant C ₇ is added to T depending on whether the shooting state is macro shooting (steps ST16 to ST19). This constant is
It may be changed depending on the type of macro lens. In the case of macro photography, since a very narrow range is photographed, the color measurement range is also narrowed at the same time, and there is a high possibility that wrong color measurement will be performed. In addition to this, the presence or absence of tripod shooting, the use of a self-timer,
Alternatively, the value of T may be changed by using a strobe.

After that, how much the measured color values deviate from the color temperature locus is obtained. As a result, if there is a large deviation, it is highly likely that wrong colorimetry was performed, and the value of T is set to a large value (steps ST20 to S20).
T22).

Here, the color temperature locus, as shown in FIG. 11, is 2 / 3πr for each of the R, G, and B color stimuli.
When displayed as a vector in the direction shifted by ad, G
The axes are substantially the same on the R (red) -B (blue) axis orthogonal to the (green) -M (red) axis. Therefore, the deviation from the color temperature locus is
The distance in the GM axis direction is used instead. If the result of correct color measurement is an abnormally green ray, there is no problem because it actually looks green.

Next, using the constant C ₉ , the value of T indicating the incorrectness is converted into the correction value in the BM direction (step ST23). Here, 1 is added so that the value is not divided by 0 and the value in the GM direction does not become large. The above steps ST2 to ST23 are the part of the processing operation for estimating the incorrectness of the colorimetric value from the state of the camera.

Next, the value of the temporary G direction is calculated (step ST24), and it is further determined whether the value of the temporary G calculated here is positive or negative (step ST25).
Here, if the provisional G value is positive, it is directly adopted as the G'value, and the process proceeds to step ST26.

Then, it is judged whether the value in the R-B direction orthogonal to the GM direction is on the R side or the B side, the value on the opposite side is set to 0, and the value of | R-B | It is adopted (steps ST26 to ST31). Furthermore, the correction of the color temperature locus direction may be additionally performed by T.

On the other hand, in step ST25, if the provisional G value calculated in step ST24 is negative,
The value of G'is set to 0 (step ST32), and the current R '
The value of B'is added to the provisional G to obtain a new value of R'.B 'and the calculation is performed again (step ST3).
3, ST34).

In the above calculation, as shown in FIG. 12, when the display as shown in FIG. 11 is cancelled, the portions which do not appear, that is, the portions shown by the diagonal lines in the figure, so-called UCR ( Undercolor) is omitted. U omitted in the above calculation
The amount of CR is restored by the processing operation of subsequent steps ST35 to ST39. The above steps ST24 to ST
Reference numeral 39 denotes a processing operation portion for correcting the colorimetric value with the degree of inaccuracy.

As described above, according to this embodiment, in the case of a close-up of a tree, a forest, or the like where a certain color is likely to fill the screen, the color information to be recorded should be close to the color temperature locus. By applying the correction, it is possible to reduce erroneous correction.

The recording unit 3 may be a magnetic recording on an IC card / film magnetic layer, a recording system in which the film base surface is slightly depressed, for example, Japanese Patent Application No.
It is conceivable to record minute pits or digital data on the film base surface by using a minute heating element of No. 48771. Next, a second embodiment of the present invention will be described.

The second embodiment differs from the first embodiment described above only in the processing operation. Therefore, all other components are the same, and only the flowchart is shown here. In addition, in steps ST71 to ST93 in the flowcharts of FIGS.
Step ST of the flow chart of the first embodiment described above
1 to ST23, the description is omitted here to avoid duplication.

In the above-described first embodiment, the degree of incorrectness of the colorimetric value is predicted, and when it is predicted that the colorimetric value is not correct, the operation is performed along the color temperature locus.
In this embodiment, the data of several light sources are recorded in advance, and when it is predicted that the data is incorrect, the data of the nearest light source is made to approach.

Referring to FIG. 16, the R, G, B3 stimulus values similar to those shown in FIG. 11 are considered as vectors in three directions, and colors are expressed on a two-dimensional plane. The light source data stored in advance is displayed as a white circle. Figure 16 (a)
Shows the whole, and FIG. 16 (b) shows a part. Further, the black circle in FIG. 7B indicates the colorimetric value, and the arrow indicates the correction direction.

In steps ST94 to ST105, so-called undercolor removal processing is performed. Next, in steps ST106 to ST112, the distance between each light source and the colorimetric value is calculated. This distance is
For convenience of calculation, it is recorded in Di in the form of a square.

Next, in steps ST113 to ST119, the light source with the shortest distance is selected. Then, in steps ST120 to ST122, the above step ST
The photometric values R ', G', and B'are corrected by the correctness value T obtained up to 94.

Then, steps ST123 to ST127
Thus, the undercolor removed in steps ST94 to ST105 described above is restored for the newly corrected amount.

As described above, according to the second embodiment, the correction amount is erroneously adjusted to the color temperature locus even if the image is taken under a light source such as a fluorescent lamp which is slightly deviated from the color temperature locus. Is eliminated, a more appropriate white balance correction is performed.

[0048]

As described above, according to the present invention, the fading phenomenon does not occur even in the case of a close-up of a tree, a forest, or the like, where a constant color is likely to fill the screen, and the color of the subject may be different. Since it is possible to provide a recording device for a camera that is not affected by the influence of incorrect correction,
Even if the color of the subject on the screen is biased, the fading phenomenon is unlikely to occur, and the light source light color value with high satisfaction of the white balance color reproduction can be recorded.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a communication system of a camera to which a recording device for a camera of the present invention is applied.

FIG. 2 is a diagram showing, as an example of the present invention, a scene showing a relationship between a subject and a camera angle of view when a single-lens reflex camera is used.

FIG. 3 is a diagram showing an arrangement example of a camera body, a lens and a color temperature sensor of FIG.

4 (a) is a diagram showing an optical path of a so-called finder portion after the focus screen of FIG. 3 without being folded back, and FIG. 4 (b) is a diagram showing light scattering characteristics of the focus screen of FIG. Is.

5 is a diagram showing a configuration of the color sensor of FIG.

6 is an electric circuit diagram after the light receiving sensor of FIG.

FIG. 7 is a flowchart illustrating an operation for processing a detected color into a value to be actually recorded.

FIG. 8 is a flowchart illustrating an operation for processing a detected color into a value to be actually recorded.

FIG. 9 is a flowchart illustrating an operation for processing a detected color into a value to be actually recorded.

10 is a subroutine for explaining the operation in step ST1 of the flowchart of FIG.

FIG. 11 is a diagram for explaining a color temperature locus in which colors are expressed on a two-dimensional plane by considering R, G, B3 stimulus values as vectors in three directions.

FIG. 12 is a diagram for explaining an under color (UCR).

FIG. 13 is a flowchart illustrating an operation for processing a detected color into a value to be actually recorded in the second embodiment of the present invention.

FIG. 14 is a flowchart illustrating an operation for processing a detected color into a value to be actually recorded in the second embodiment of the present invention.

FIG. 15 is a flowchart illustrating an operation for processing a detected color into a value to be actually recorded in the second embodiment of the present invention.

FIG. 16 shows R, G, and B3 stimulus values as vectors in three directions and expresses colors on a two-dimensional plane. (A) is a diagram showing the whole and (b) is a diagram showing a part thereof. Is.

[Explanation of symbols]

1 ... Camera body, 2 ... Lens, 3 ... Recording unit, 4 ...
Color temperature sensor, 5 ... Subject, 6 ... Quick return mirror, 7 ... Focus screen, 8 ... Condenser lens, 9 ... Eyepiece lens, 10 ... Photographer, 11 ... Milky white diffuser plate, 12 ... Color filter, 13 ... Photosensor .

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[Procedure amendment]

[Submission date] May 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

The resistors 17 (R1), 19 (R2),
Capacitor (C1) 18, operational amplifier (OP.AMP)
Reference numeral 20 constitutes an amplifier circuit in which the offset for changing the sensitivity of the human eye to green and red and blue is changed for each of R, G and B. This amplifier circuit has a capacitor 1
8 and a high-band cut filter formed by the resistor 19 remove the noise component and pass only the optical signal (cutting is performed at a portion higher than the light quantity change frequency of the fluorescent lamp including the inverter type). ).

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] Figure 15

[Correction method] Change

[Correction content]

FIG. 15

Claims (1)

[Claims] 1. A subject light is received through a photographing lens,
A color detection unit that outputs information according to the color of the light source or the type of the light source, and a correction that corrects the color or light source type information so as to approach the color temperature locus or the prepared light source data depending on the state of the camera. A recording apparatus for a camera, comprising: a recording means for recording the information corrected by the correcting means.