JP3807109B2 - Digital camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital camera, and more particularly to a digital camera having a function of performing soft focus shooting in which a subject image is intentionally blurred.
[0002]
[Prior art]
To intentionally blur the subject image and take a soft-looking photo (soft focus photo), a silver halide camera (film photosensitive camera) uses a soft focus lens that uses the spherical aberration of the lens optical system, An optical method was used in which a soft focus filter was attached to the front of the taking lens.
[0003]
On the other hand, in the case of a digital camera, an optical method is possible, but after shooting, a soft focus image is obtained by performing image processing using a computer or the like on the obtained image data. It was like that.
[0004]
[Problems to be solved by the invention]
However, conventionally, the captured image data is subjected to a blurring process with a certain strength, and depending on the subject, a sufficient video effect may not be obtained.
[0005]
Further, in the conventional image processing, even if a certain intensity of blur is applied, it is not considered that the degree of effect varies depending on the shooting magnification. In other words, it can be understood that, when a soft focus process with a constant intensity is performed, the effect is more likely to appear in a subject with more high-frequency components. Therefore, when soft focus processing with a constant intensity is performed regardless of the shooting distance, a distant view has a strong soft focus effect against the photographer's intention, and a close view has a weak soft focus effect against the photographer's intention. There was a problem in the video effect because it would be expressed.
[0006]
The present invention has been made in order to solve the above-described problems. The first object of the present invention is to provide a digital camera in which a photographer can set a soft focus effect. A second object of the present invention is to provide a digital camera that can express the soft focus effect.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a digital camera comprising an image processing means for forming a subject image on an image pickup device by a photographing lens and converting the image into an image signal, and performing soft focus processing on the image signal. The measuring means for measuring the distance to the subject and the control means for increasing the degree of soft focus processing in the image processing means as the distance measured by the measuring means is closer.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
<A. Basic configuration and operation of digital camera>
First, the basic configuration and operation of a digital camera will be described with reference to FIGS. FIG. 1 is a block diagram of a digital camera 100 having a configuration for realizing an image processing method for a digital camera according to the present invention.
[0010]
As shown in FIG. 1, a digital camera 100 includes a main microcomputer (hereinafter abbreviated as a main microcomputer) 1 and controls the functions of each component described below.
[0011]
The configuration controlled by the main microcomputer 1 includes a distance measuring module 2 (measuring means) that receives reflected light from the subject and outputs distance information of the subject, a power switch for the photographer to operate the digital camera 100, and software Switch group 3 including mode setting dial 30 (setting means) for automatically setting the strength of the focus processing and automatically setting the strength of the soft focus processing according to the shooting distance (shooting magnification), and the model for each digital camera 100 Electrically rewritable ROM (EEPROM) 4 that records inspection values at the time of shipment from the factory and various setting values immediately before the power is turned off, a liquid crystal display (LCD) that displays subject images and setting values for photographing Display member 5 and the like, an external input for inputting / outputting image information and the like to a personal computer and an external monitor A face 6; a removable recording medium 7 for recording captured image information; a RAM 8 for processing the captured image data; and a solid-state imaging device (here, using a CCD) for capturing a subject image via a lens. Output from the solid-state image sensor 9, the image sensor driver (timing generator: sometimes referred to as TG) 10 for generating a pulse for driving the solid-state image sensor 9. The analog amplifier 11 that amplifies the analog signal of the image, the image analog signal amplified by the analog amplifier 11 is digitally converted, and the A / D converter 12 and the focus lens group 14 that are output to the main microcomputer 1 are driven in the optical axis direction. Focus driver / position detection sensor for detecting the position of the focus lens group 14 It is 3 and the like.
[0012]
The focus lens group 14 constitutes a part of an imaging lens group that is an imaging optical system, and the imaging lens group includes a fixed lens group 141 that is fixed in addition to the focus lens group 14.
[0013]
FIG. 2 shows the configuration of the mode setting dial 30. As shown in FIG. 2, the mode setting dial 30 is configured to be able to switch soft focus processing ON / OFF, automatically set soft focus processing, and manually set the strength of soft focus processing.
[0014]
FIG. 3 is a conceptual diagram illustrating the basic configuration of the solid-state image sensor 9. The solid-state imaging device 9 is configured by arranging a plurality of light receiving cell rows 21L in which a plurality of light receiving cells 21 are arranged. The light receiving cell 21 is composed of a photoelectric conversion element that converts light energy into electric energy. When the light receiving cell 21 is irradiated with light, a charge is generated, and the generated charge is generated at a predetermined timing generated by the image sensor driver 10. The output signal is the image signal.
[0015]
In FIG. 3, the charge of each light receiving cell 21 is transferred to the transfer gate 22 by opening the transfer gate 22 attached to the light receiving cell row 21 </ b> L (changing the depth of the potential well so that the charge of the light receiving cell 21 is moved). The data is discharged to the transfer register 23 attached to the. The charges discharged to the transfer register 23 move in the transfer register 23 by a CCD operation for moving the charges by sequentially changing the depth of the potential well, and are transferred to the read register 24 orthogonal to the transfer register 23. In the read register 24 as well, charges are transferred by the CCD operation and output from the output unit 25 to the outside. The transfer register 23 and the read register 24 are shielded from light and do not cause photoelectric conversion by themselves.
[0016]
The image signal output from the solid-state imaging device 9 is an analog value and is weak, so it is amplified by the analog amplifier 11, converted to a digital value by the A / D converter 12, and given to the main microcomputer 1. The main microcomputer 1 performs various image processing on the given digital image signal and displays it as a subject image on the display member 5, and compresses it based on the JPEG method and records it on the recording medium 7 in accordance with the photographer's operation. It should be noted that since there may be a case where only the memory built in the main microcomputer 1 cannot cope with the image processing, arithmetic processing or the like is performed using the RAM 8. Since the main microcomputer 1 performs various image processing (including soft focus processing described later) on the image signal as described above, it has a function as image processing means, and controls image processing and will be described later. It also has a function as a control means for controlling the degree of soft focus processing.
[0017]
The digital camera 100 can be switched between a shooting mode and a playback mode. When the digital camera 100 is in the shooting mode, the solid-state imaging device 9 always outputs an image signal, and the subject image is displayed on the display member 5 as a moving image. Will be. The photographer can record the image data of the desired image on the recording medium 7 by pressing the exposure start switch when the image on the display member 5 becomes the desired image. On the other hand, when the digital camera 100 is in the playback mode state, the image data recorded on the recording medium 7 can be displayed on the display member 5.
[0018]
<B. Operation according to the invention>
Next, the operation according to the present invention will be described with reference to FIGS. 4 to 8 are flow charts for explaining the operation according to the present invention, and the portions marked with symbols (1) to (6) mean that the same symbols are connected to each other.
[0019]
<B-1. Preliminary action>
First, a preparatory operation before starting actual shooting will be described. As shown in FIG. 4, when the power switch is turned on (step ST1), the main microcomputer 1 is reset (step ST2). Since each port of the main microcomputer 1 is in a default state due to the reset, initial setting of the main microcomputer 1 is performed such as setting a port to be used (step ST3).
[0020]
Next, the inspection value at the time of shipment regarding the model difference and various setting values immediately before the power is turned off, for example, the flash mode type or the image compression mode type are read from the EEPROM 4 (step ST4).
[0021]
Next, the presence / absence of the recording medium 7, the type and the recordable capacity based on the type are confirmed (step ST5), and the focus lens group 14 is set in the EEPROM 4 while monitoring the lens position by the focus driver / position detection sensor 13. After moving to the initial position (step ST6), the display member 5 is activated (step ST7). At this stage, the solid-state imaging device 9 is not operating, and the display member 5 is only lit to notify the photographer of the activation of the display member 5. At this time, various setting values immediately before the power is turned off and the recordable capacity of the recording medium 7 are displayed to notify the photographer.
[0022]
Then, the main microcomputer 1 performs initial settings such as setting the exposure time to 1/30 seconds in the image sensor driver (TG) 10 as a spare for the imaging operation (step ST8). Here, the exposure time is a time for accumulating charges in the light receiving cell 21, and can be referred to as a so-called shutter speed (sometimes referred to as SS) value.
[0023]
When the initial setting of the image sensor driver 10 is completed and the image sensor driver 10 operates, an image signal is output from the solid-state image sensor 9 and an image is displayed on the display member 5. At this time, the gain of the analog amplifier 11 is also set to a predetermined initial value, for example, 1 (step ST9).
[0024]
The main microcomputer 1 monitors the switch operation of the switch group 3 while displaying an image on the display member 5 (step ST10), and waits for the next camera operation. If the photographer does not operate the camera using the switch group 3 for a certain period of time by the timer function inside the main microcomputer 1, the power is turned off to save power consumption. Usually, this fixed time is set to about several minutes.
[0025]
The photographer changes the mode from the normal mode to the soft focus mode by rotating the mode setting dial 30 in the switch group 3, and further switches the exposure start switch (hereinafter referred to as a release switch) in the switch group 3. When a half-press operation (hereinafter referred to as S1 operation) is performed, the main microcomputer 1 detects it (step ST11), and in step ST12 shown in FIG. 5, the distance measurement module 2 is driven to move the distance from the camera to the subject. Information is obtained (step ST12). If the release switch is not in the S1 operation state, the operations after step ST10 are repeated.
[0026]
When the photographer performs the S1 operation, the distance measuring module 2 receives the reflected light from the subject by capturing the subject in an optical viewfinder (not shown), and the distance from the camera to the subject. Information about is obtained. Here, a conventional external light passive module or the like is used as the distance measuring module 2.
[0027]
Since the distance measurement principle is general, detailed description is omitted, but the output of the distance measurement module 2 is given as a value corresponding to the distance, and the information on the correspondence is recorded in the EEPROM 4 as an inspection value before shipment. ing. Therefore, the subject distance is obtained from the output of the distance measuring module 2 and collated with the focal length information of the photographing lens recorded in advance in the EEPROM 4 to thereby determine the amount of feeding (the feeding information) of the focus lens group 14 to be focused on the subject. Calculate (step ST13).
[0028]
Based on the payout information of the focus lens group 14 calculated in step ST13, the main microcomputer 1 controls the focus driver / position detection sensor 13 to drive the focus lens group 14, and the position is monitored by the position detection sensor. Thus, the target position is moved (step ST14).
[0029]
As described above, when the digital camera 100 is in the shooting mode state, the solid-state image sensor 9 always outputs an image signal. Therefore, when the subject is captured in an optical viewfinder (not shown), the subject is solid. The image is picked up by the image pickup device 9 (step ST15), and the image data of the subject is taken into the main microcomputer 1 (step ST16).
[0030]
The main microcomputer 1 calculates an exposure control value at which the subject is properly exposed from the brightness information of the subject. Here, the exposure control value includes a so-called shutter speed (sometimes referred to as SS) value that defines a time (exposure time) for accumulating charges in the light receiving cell 21, a gain of the analog amplifier 11, and the like. In the simplest case, the shutter speed is defined as the time from the discharge of the light receiving cell 21 to the closing of the transfer gate 22 and the next opening, taking the configuration of FIG. 3 as an example.
[0031]
Then, the main microcomputer 1 sets the calculated gain in the analog amplifier 11 and the shutter speed value in the image sensor driver 10 (step ST17).
[0032]
Next, the main microcomputer 1 determines the setting position of the mode setting dial 30 to determine whether or not the soft focus automatic setting mode is set (step ST18). In the soft focus automatic setting mode, the photographing magnification β is calculated from the subject distance calculated in step ST13 and the focal length information of the photographing lens stored in advance in the EEPROM 4. Here, the formula for calculating the shooting magnification is shooting magnification = focal length / subject distance (step ST181).
[0033]
Next, the main microcomputer 1 determines whether or not the photographing magnification is 1/30 or more (step ST182). If the shooting magnification β is 1/30 or more, a strong soft focus processing coefficient is set (step ST183), and if not, a weak soft focus processing coefficient is set (step ST184). As a result, a strong soft focus process is performed for a near scene where the shooting magnification β increases, and a weak soft focus process is performed for a distant scene where the shooting magnification β decreases. As a result, a constant soft focus effect can be achieved regardless of the shooting distance (shooting magnification). The photographing magnification 1/30 is a guide value for setting a soft focus processing coefficient, and is not necessarily limited to this value.
[0034]
Here, strong soft focus processing and weak soft focus processing will be described. As an example of the soft focus processing method, there is a method of adding pixel data to be subjected to the soft focus processing to a value obtained by multiplying pixel data adjacent thereto by a predetermined coefficient. This method will be further described with reference to FIGS.
[0035]
FIG. 8 is a determinant that describes soft focus processing that is weak (weak blurring), and FIG. 9 is a determinant that describes soft focus processing that is strong (strong blurring). In FIG. 8 and FIG. 9, coefficients are arranged corresponding to the arrangement of pixel data, and coefficient 1 is a matrix corresponding to pixel data to be subjected to soft focus processing (hereinafter referred to as target pixel data). Located in the middle of the formula.
[0036]
As shown in FIG. 8, the pixel data adjacent to the target pixel data (that is, the pixel data having a coefficient of 1) vertically and horizontally are all multiplied by 1/7, and the pixel data at the diagonal position of the target pixel data is all 1 / 10 times. Then, the soft focus process is performed by adding each value multiplied by the coefficient to the target pixel data. Accordingly, the value of the target pixel data is larger than that before the soft focus process. When the processing for one pixel data is completed, the soft focus processing is performed for the next target pixel data.
[0037]
For example, if the pixel data on the left side of the pixel data of coefficient 1 shown in FIG. 8 is the next target pixel data, the value of the pixel data of coefficient 1 is multiplied by the coefficient and added to the next target pixel data. In this case, the data before the soft focus processing is multiplied by the coefficient. Therefore, an area for storing unprocessed soft focus data and an area for storing soft focus processed data are provided in the RAM 8.
[0038]
By performing such processing for each pixel data, each pixel data is added with a value obtained by multiplying the surrounding pixel data by a coefficient, so that there is an extreme data difference between the pixel data. As a result, an image with a blurred contrast or outline can be obtained.
[0039]
The same process is performed when performing a strong soft focus process. In this case, the coefficient value is increased and the number of pixel data multiplied by the coefficient is increased. That is, as shown in FIG. 9, the pixel data adjacent to the target pixel data (that is, the pixel data having a coefficient of 1) in the vertical and horizontal directions is multiplied by 1 / 3.5, and the pixel data at the diagonal position of the target pixel data is The pixel data on the outer periphery adjacent to the pixel data multiplied by 1/5 and the pixel data multiplied by 1 / 3.5 are both multiplied by 1/7, and the pixel data on the outer periphery adjacent to the pixel data multiplied by 1/5 are Both are multiplied by 1/8, and the outer peripheral pixel data at the diagonal position of the pixel data multiplied by 1/5 are all multiplied by 1/10. Then, the soft focus process is performed by adding each value multiplied by the coefficient to the target pixel data.
[0040]
The soft focus processing coefficients shown in FIGS. 8 and 9 are stored in the EEPROM 4 in advance.
[0041]
If it is determined in step ST18 shown in FIG. 5 that the soft focus automatic setting mode is not set, the main microcomputer 1 sets the mode setting dial 30 to either the strong or weak soft focus mode as shown in FIG. (Step ST19), and if the soft focus mode is set to either strong or weak, a weak soft focus processing coefficient is set (step ST20).
[0042]
Here, when the soft focus mode is not set, that is, when the mode setting dial 30 is set to OFF, the main microcomputer 1 confirms whether or not the release switch S1 is operated (step ST23), and the S1 operation is not turned off. In the case (when the photographer has not released his / her finger from the release switch), the process waits until the photographer performs a full-press operation (referred to as S2 operation) of the release switch. In addition, when S1 operation is turned off, the operation | movement after step ST10 will be repeated.
[0043]
Next, the main microcomputer 1 confirms whether or not the mode setting dial 30 is set to the strong soft focus mode (step ST21). When the strong soft focus mode is set, the main microcomputer 1 performs the strong soft focus processing. The processing coefficient is set and updated (step ST22).
[0044]
When the strong soft focus mode is not set, that is, when the weak soft focus mode is set, the operation after step ST23 is continued using the processing coefficient set in step ST20.
[0045]
Next, the main microcomputer 1 confirms the presence or absence of the S1 operation of the release switch (step ST23). If the S1 operation is not turned off (if the photographer has not released his / her finger from the release switch), the photographer will Wait until the switch is fully pressed (referred to as S2 operation). In addition, when S1 operation is turned off, the operation | movement after step ST10 will be repeated.
[0046]
<B-2. Main shooting>
After the main microcomputer 1 detects the S2 operation, the main photographing operation is started. First, as shown in FIG. 7, the imaging operation is performed by controlling the solid-state imaging device 9 so as to obtain the appropriate shutter speed obtained in step ST17 (see FIG. 5) (step ST25). After the imaging is completed, the image signal from the solid-state imaging device 9 is amplified by the analog amplifier 11 set to the appropriate gain calculated in step ST17, converted into a digital output by the A / D converter 12, and main as digital image data. The data is taken into the microcomputer 1 (step ST26).
[0047]
The captured image data is subjected to general image processing such as color balance processing (step ST27), and it is determined whether or not the main microcomputer 1 is in the soft focus mode (step ST28). If there is, soft focus processing is performed based on the processing coefficients set in step ST183 or ST184 shown in FIG. 5 and step ST20 or ST22 shown in FIG. 6 (step ST29).
[0048]
Thereafter, the soft focus processed data is compressed on the RAM 8 for recording on the recording medium 7 (step ST30), and the compressed soft focus processed data is recorded on the recording medium 7 (step ST31). Since image data generally has a large data size, data compression is performed in order to record more on the recording medium 7. The JPEG method is used as a general compression method.
[0049]
After step ST31, the main microcomputer 1 confirms whether or not the photographer is performing the S1 and S2 operations, and detects that the S1 and S2 operations are not performed, that is, when the finger is released from the release switch. 4 repeats the operations after step ST10 shown in FIG. When S1 and S2 operations are performed, that is, when the finger is not released from the release switch, the release switch confirmation operation is continued until the finger is released.
[0050]
Note that if it is determined in step ST28 that the mode is not the soft focus mode, that is, in the normal shooting mode, the shooting operation in steps ST30 to ST32 is performed. Will be recorded.
[0051]
The above is the operation of the digital camera according to the present invention. Not only the captured video data is recorded on the recording medium 7, but also when an external device such as a personal computer is connected to the external interface 6 and output to the external interface 6. I do not care. The recording medium 7 includes a smart media, a compact flash (CF) card, a PC memory card, and the like.
[0052]
Further, camera control from an external device via the external interface 6 is also possible. The external interface 6 includes a terminal to which a serial cable such as RS-422 can be connected, an NTSC output terminal corresponding to output to a television receiver, a printer output terminal to a printer, and the like.
[0053]
<B-3. Characteristic effects>
As described above, according to the digital camera of the present invention, it is possible to perform soft focus shooting with at least two-stage mode setting of strong soft focus mode and weak soft focus mode. Can be used properly. Also, by changing the degree of soft focus processing according to the shooting magnification of the subject, an image having a uniform soft focus effect can be obtained regardless of the shooting magnification of the subject.
[0054]
<B-4. Modification>
In the above description, an example in which the soft focus mode can be set to two types of strength and weakness has been described, but the soft focus mode is not limited to two types. Moreover, you may enable it to change selectively.
[0055]
In the above description, an example in which the processing coefficient of the soft focus mode is preset in the EEPROM 4 has been described. It may be possible to set the strength.
[0056]
【The invention's effect】
According to the digital camera of the first aspect of the present invention, when the distance of the subject is short, the degree of soft focus processing is increased, so that a constant soft focus effect can be achieved regardless of the shooting distance. It becomes.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a digital camera having a configuration for realizing an image processing method of a digital camera according to the present invention.
FIG. 2 is a diagram illustrating a configuration of a mode setting dial.
FIG. 3 is a conceptual diagram illustrating the configuration and operation of a solid-state image sensor.
FIG. 4 is a flowchart illustrating an image processing method of the digital camera according to the present invention.
FIG. 5 is a flowchart illustrating an image processing method of the digital camera according to the present invention.
FIG. 6 is a flowchart illustrating an image processing method of the digital camera according to the present invention.
FIG. 7 is a flowchart illustrating an image processing method of the digital camera according to the present invention.
FIG. 8 is a diagram illustrating an example of a technique for soft focus processing.
FIG. 9 is a diagram illustrating an example of a technique for soft focus processing.
[Explanation of symbols]
30 Mode setting dial.

Claims (3)

In a digital camera provided with an image processing means for forming a subject image on an image sensor by an imaging lens and converting the image into an image signal, and soft-focusing the image signal,
Measuring means for measuring the distance to the subject;
A digital camera comprising: control means for increasing the degree of soft focus processing in the image processing means as the distance measured by the measuring means is closer . The control means calculates a photographing magnification based on a focal length of the photographing lens and a distance to the subject measured by the measuring means, and increases a soft focus processing coefficient as the photographing magnification increases. 1. The digital camera according to 1. The control means includes
Centering on the target pixel data to be subjected to the soft focus processing, each of the pixel data around the target pixel data is multiplied by the soft focus processing coefficient, and each value multiplied by the coefficient is added to the target pixel data. The digital camera according to claim 2, wherein the soft focus processing is performed on the target pixel data.

Images