JP2000078601A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic camera that can photograph a general object and an image on a negative film and conducts excellent white balance processing even in the case of photographing the image on the negative film. SOLUTION: The electronic camera 1 can photograph a developed negative film 6 by loading a film adaptor 2 to which the developed negative film 6 is loaded to the electronic camera 1, and only a photographing signal within a film image frame smaller among all photographing valid areas of a charge coupled device CCD 12 is processed as an object in the white balance adjustment for the film photographing state to enhance the accuracy of white balance adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera capable of photographing a general subject and photographing an image of a developed negative film.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 5-252436 discloses an electronic camera with a built-in image sensor capable of taking a picture of a general subject and also taking in an image of a developed negative film. The still video camera compatible with a film adapter provides a low-cost camera with a simple optical design without providing an optical mechanism for guiding the transmitted light of the film to a photometric / colorimetric element of the still video camera.

A video camera apparatus disclosed in Japanese Patent Application Laid-Open No. 9-70049 is designed to automatically determine whether a negative film is being video-recorded and perform a negative / positive reversal process. Further, the imaging apparatus disclosed in Japanese Patent Application Laid-Open No. H10-164605 automatically determines negative film shooting and automatically performs negative / positive reversal control.

[0004]

The aspect ratio of the photographing range of a negative film (Leica size) is 2: 3.

On the other hand, the aspect ratio of the photographing range of a photographing element (CCD) applied to a video camera or an image pickup apparatus is not always 2: 3, but may be, for example, 4: 5.

However, in the above-mentioned conventional video camera or the like, when an image of a negative film is photographed other than the usual photographing of an object, the image is taken in and the gradation conversion is adjusted (white balance). No consideration is given to the effective area of the captured image.

FIG. 7 is a diagram showing the entire effective area of the CCD imaging range and the film frame of the negative film. Even when a negative video image is captured by the above-described conventional video camera or the like, the white balance is adjusted based on the imaging data of the effective area 101. Therefore, the image data of the outside frame area 102a of the frame portion other than the image outside the film image frame area 102 is also subjected to the image adjustment, and the appropriate white balance cannot be adjusted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to switch between a shooting mode for a general subject and a shooting mode for a negative film image, and to shoot a negative film image. An object of the present invention is to provide an electronic camera capable of performing a good gradation conversion process (white balance) even in such a case.

[0009]

An electronic camera according to a first aspect of the present invention is capable of performing general photographing and capable of photographing a developed negative film through a film adapter device. A photographing mode selecting unit for selecting either a photographing mode or a negative film photographing mode; and a signal amplifying unit for independently amplifying the R component, the G component, and the B component of the image signal photoelectrically converted by the image sensor. A / D conversion means for converting an image signal into a digital image signal by the signal amplification means, area setting means for setting different signal processing areas in accordance with the shooting mode, and amplification of each of the signal amplification means Signal image width ratio that can change each amplification factor based on the digital image signal of the set processing area in the negative film shooting mode Signal processing means for processing the digital image signal by the A / D conversion means, and signal processing parameter determining means for determining processing parameters in the signal processing means based on the digital image signal in the set processing area. The amplification factor is set for the set processing area according to the selected photographing mode, and the signal processing is executed.

According to a second aspect of the present invention, in the electronic camera according to the first aspect, when the negative film photographing mode is selected, an area smaller than when the general photographing mode is selected is set.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a state in which a film adapter device 2 is mounted on an electronic camera 1 according to an embodiment of the present invention. FIG. 2 is a main block configuration diagram of the electronic camera 1.

As shown in FIG. 1, an electronic camera 1 according to the present embodiment includes a film adapter device 2 on a front surface of a lens barrel 1a in addition to capturing a substantial general object by a CCD 12 serving as an image sensor. The camera is also capable of capturing an image of the developed negative film 6 in a mounted state. A mode for photographing a general subject is referred to as a “general photographing mode”, and a mode for photographing an image of the developed negative film 6 is referred to as a “film photographing mode (negative film photographing mode)”.

The film adapter device 2 has a macro lens 3 and a diffusion plate 4 for taking in external light, and a film holder 5 in which a developed film 6 is loaded.
Can be inserted. The film adapter device 2 can be attached to the front end of the lens barrel 1a of the electronic camera 1. This mounting state is detected by a film adapter detection switch 19 as a photographing mode selecting means for instructing the photographing mode by a switch disposed at the front end. When the adapter device 2 is mounted, the electronic camera 1 is set to the film shooting mode, and otherwise, the electronic camera 1 is set to the general shooting mode.

The entire operation of the electronic camera 1 is controlled by a microcomputer 21. The microcomputer 21 includes area setting means for setting different imaging signal processing areas between the general shooting mode and the film shooting mode, signal amplification changing means for changing the amplification factor of the RGB amplifier circuit, and white balance adjustment parameters. A signal processing parameter determining means for determining is built in.

In the electronic camera 1, first, the shooting mode is set to one of the general shooting mode and the film shooting mode in accordance with the output signal of the film adapter detection switch 19. With this mode setting, the processing area of the imaging signal at the time of shooting is set. That is, in the general photographing mode, the entire effective area 10 of the CCD imaging range in FIG.
1 is set as the processing area, and in the film shooting mode, the film image frame area 102 of the negative film 6 is set as the processing area.

As shown in FIG. 2, a general subject or subject light from an image of a developed film is taken in through a photographing lens 11 and formed on a photoelectric conversion surface of a CCD 12 which is an image pickup device. Image. With the first-stage ON operation of the release switch 20, the image sensor C
An imaging signal is output from the CD 12. The imaging signal is
Signal amplifying means, which are independent amplifiers R-AMP13a, G-AMP13b, B for R, G, and B color components
-Amplified by an amplifier circuit 13 composed of an AMP 13c, and further amplified by an A / D conversion circuit 14 as A / D conversion means.
D conversion is performed. The A / D converted digital imaging signal is
The microcomputer 21 is temporarily loaded into the microcomputer 21 and performs processing such as setting of an amplification factor for white balance and setting of a gradation conversion characteristic corresponding to a shooting mode set as described later.

Thereafter, a general subject image or an image of the developed film 6 is picked up by the CCD 12 in accordance with the second-stage ON operation of the release switch 20. The image pickup signal is amplified by an independent amplification circuit 13 for R, G, and B systems according to an amplification factor set corresponding to the above-described photographing mode, converted to a digital signal by an A / D conversion circuit 14, and subjected to signal processing. The white balance is adjusted by the signal processing circuit 15 based on the gradation conversion characteristics set according to the shooting mode and the state of the image, and is recorded as an image signal in a frame memory (not shown).

In the general photographing mode, a constant amplification factor is always set for each of R, G, and B in the amplification circuit 13. On the other hand, in the case of the film photographing mode, since the negative film itself has a red tint and a difference in characteristics depending on the film maker, accurate white balance processing can be performed only by the gradation conversion processing by the A / D conversion circuit 14. Since it is impossible, it is necessary to set the amplification factor again based on the imaging signal.

Therefore, in the film photographing mode, the R / G of the signal after the A / D conversion of the image signal once taken in is taken.
The luminance component of each B is integrated with each pixel value, and the integrated value ratio is obtained. The reciprocal ratio is determined by the R, G, and B of the amplifier circuit 13.
Adopted as the amplification ratio for each system, it enables more accurate white balance processing.

The above-mentioned gradation conversion characteristic is a characteristic for performing gradation conversion for white balance adjustment performed on image data after A / D conversion. In a general photographing mode, a light source at the time of photographing is used. It is necessary to adjust and set the conversion characteristics depending on the difference between sunlight, fluorescent light and the like.

FIG. 3 is a gradation conversion characteristic line showing a gradation conversion output value (8 bits) for each of R, G, and B with respect to an image data input value (10 bits) after A / D conversion in general photographing. It is a figure and shows the conversion characteristic as a signal processing parameter with respect to the imaging signal of the object by a standard light source. When photographing is performed with a light source other than the standard light source, the appropriate conversion characteristics for R, G, and B change within the ranges Ry, Gy, and By.

The conversion characteristics are set by the microcomputer 21 based on the A / D conversion output taken after the release switch 20 is turned on in the first stage.
One conversion characteristic within the width of Gy, By is selected. After the second stage is turned on, the signal processing circuit 15 performs gradation conversion processing in accordance with the selected conversion characteristic, and a white-balanced imaging signal is output from the signal processing circuit 15 to the outside. Note that the gradation conversion processing and the imaging output in the general shooting mode are performed in the entire imaging effective area 10 of the CCD 12.
1 is processed and output.

On the other hand, in the film photographing mode, as described above, the conversion characteristics of the negative film itself are different due to the red tint and the characteristics of each film maker. FIG.
Indicates an inverted gradation conversion characteristic line (inverted tone) indicating a gradation conversion output value (8 bits) for each of R, G, and B with respect to an imaging data input value (10 bits) after A / D conversion in negative film shooting. FIG. 7 is a graph showing a conversion characteristic as a signal processing parameter for an image pickup signal of a subject by a standard negative film. Due to the above-mentioned differences in characteristics among film manufacturers, etc., the proper conversion characteristics for R, G, B
It changes within the width of x, Gx, Bx.

The setting of the proper conversion characteristics is determined by the microcomputer 21 based on the A / D conversion output taken in after the release switch 20 is turned on in the first stage.
One conversion characteristic within the width of the range Rx, Gx, Bx, etc. is selected and set. Then, after the second stage is turned on, gradation conversion (inversion) processing is performed in the signal processing circuit 15 according to the selected conversion characteristic, and an image pickup signal with a white balance is output from the signal processing circuit 15 to the outside. Note that, including the setting of the above-described amplification factor in the film shooting mode, the setting and conversion processing of the gradation conversion characteristic and the imaging output are based on CC.
Processed with respect to the film frame area 102 of D12,
It shall be output.

Next, the imaging process in the electronic camera according to the present embodiment will be described with reference to the flowcharts of FIGS. When the imaging process starts, as shown in FIG. 5, it is confirmed in step S1 that the first-stage switch of the release switch 20 is on, and in step S2, the R, G,
The amplification factor for each B is set to a certain default gain. In steps S3, S4, S5, the imaging signal output of the CCD 12 is read out, and the amplification circuit 13 amplifies the imaging signal for each of R, G, B with the above default gain.
The conversion circuit 14 converts the digital signals into digital signals for each of R, G, and B. The digital signal is taken into the microcomputer 21.

Subsequently, in step S6, it is checked whether the photographing mode set by turning on / off the adapter detecting switch 19 is the general photographing mode or the film photographing mode. In the case of the general shooting mode, step S
The process proceeds to step S10, but in the case of the film shooting mode, step S
Go to 7 or less.

In steps S7, S8, and S9, the luminance components for each of R, G, and B are integrated into pixel values limited to the image pickup signals in the specific film image frame area 102, and the integrated value ratio a: b:
Find c. The reciprocal ratio 1 / a: 1 / b; 1 / c is adopted as the R, G, B system amplification factor ratio of the amplifier circuit 13,
Set the gain.

If it is detected in step S10 that the release switch 20 has been turned on for the second stage, the flow proceeds to step S11 and subsequent steps (see FIG. 6). If it is off, the process returns to step S1.

In step S11, the output of the image pickup signal of the CCD 12 is read, and in step S12, the image pickup signal is amplified by the amplifier circuit 13. When the setting mode is the general photographing mode, amplification is performed at a predetermined constant amplification rate. In the case of the film photographing mode, amplification is performed with a gain of an amplification factor ratio of 1 / a: 1 / b; 1 / c for each of R, G, and B of the amplifier circuit 13 described above.

In step S13, the image signal amplified by the A / D conversion circuit 14 is A / D-converted.
The photographing mode set in step 4 is checked. If the photographing mode is set to the general photographing mode, the process proceeds to step S15. If the photographing mode is set to the film photographing mode, the process proceeds to step S16.
Proceed to.

In step S15, a gradation conversion curve (gradation conversion characteristic) for the entire imaging effective area 101 is selected by the CCD microcomputer 21.
Proceed to 17.

On the other hand, in step S16, a gradation conversion curve (inversion gradation conversion characteristic) for the film frame area 102 is selected by the CCD microcomputer 21, and the flow advances to step S17.

In step S17, the white balance is adjusted by performing a gradation conversion process on the processing area using the gradation conversion curve selected in each of the photographing modes. In step S18, the image signal subjected to the gradation conversion is recorded in a frame memory (not shown), and this routine ends.

As described above, according to the electronic camera 1 of the present embodiment, the photographing mode for photographing a general subject and the photographing mode for photographing the negative film 6 are automatically set by turning on / off the film adapter detecting switch 19. Is done. Further, different processing areas (regions) on the CCD to be processed with the imaging signal are set corresponding to the imaging mode, and further, the amplification factors of the R, G, and B imaging signals for the imaging mode, and , Gradation conversion characteristics are selected. Therefore, it is possible to obtain an image signal in which good white balance adjustment has been performed not only for a general subject but also for a negative film.

In the electronic camera 1 of the above-described embodiment, the mounting state of the film adapter device 2 is automatically detected by the film adapter detection switch 19, but the mounting state is determined by turning on / off a manual switch. May be used to indicate the shooting mode.

[0036]

As described above, according to the electronic camera of the first aspect of the present invention, different processing areas to be processed by the imaging signal are set in accordance with the selected imaging mode. Since the amplification factors of the R, G, and B components of the imaging signal and the signal processing parameters for the mode are selected, imaging with good white balance adjustment is performed not only for general shooting but also for developed negative film shooting. A signal can be obtained.

According to the electronic camera according to the second aspect of the present invention, in addition to the effect of the electronic camera according to the first aspect, when photographing a developed negative film, an unnecessary area is deleted and a smaller area is imaged. Since signal processing is performed, the accuracy of white balance is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state where a film adapter device is mounted on an electronic camera according to an embodiment of the present invention.

FIG. 2 is a main block configuration diagram of the electronic camera of FIG. 1;

FIG. 3 is a diagram illustrating an example of an R value corresponding to an image data input value after A / D conversion in a general image capturing mode in an image capturing process of the electronic camera in FIG. 1;
A gradation conversion characteristic diagram showing gradation conversion output values for each of G and B.

4 is a gradation conversion showing a gradation conversion (inversion) output value for each of R, G, and B with respect to an imaging data input value after A / D conversion in a negative film photographing mode in the imaging processing of the electronic camera in FIG. Characteristic diagram.

FIG. 5 is a part of a flowchart of an imaging process of the electronic camera in FIG. 1;

FIG. 6 is a part of a flowchart of an imaging process of the electronic camera in FIG. 1;

FIG. 7 is a diagram showing an entire imaging effective area of a CCD imaging range and a film frame area of a negative film.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electronic camera 2 ... Film adapter device 13 ... Amplification circuit (signal amplification means) 14 ... A / D conversion circuit (A / D conversion means) 15 ... Signal processing circuit (signal processing means) 19 ... Film adapter detection switch (shooting mode selection means) 21... Microcomputer (area setting means, signal amplification rate changing means, signal processing parameter determination means) 101... CCD full imaging effective area (processing area) 102... Developed film Image frame area (processing area)

Claims (2)

[Claims] 1. An electronic camera capable of photographing a developed negative film through a film adapter device and capable of photographing a photographed negative film, wherein the photographing device selects one of a general photographing mode and a negative film photographing mode. A mode selection unit, an R component and a G component of an image signal photoelectrically converted by the image sensor,
Signal amplifying means for independently amplifying the B component, A / D converting means for converting an image signal from the signal amplifying means into a digital image signal, and setting different image signal processing areas according to the shooting mode A region setting means for setting, and a gain of each of the signal amplifying means, wherein in the case of a negative film photographing mode, a signal image width capable of changing each gain based on a digital image signal of a set processing area. Rate changing means; signal processing means for processing digital image signals by the A / D conversion means; signal processing parameter determining means for determining processing parameters in the signal processing means based on the digital image signals in the set processing area An electronic camera, comprising: 2. The electronic camera according to claim 1, wherein the area setting means sets an area smaller than that of the general filming mode when the negative filming mode is selected.