JP2001208954A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain at least a pan-focus position at an optional zoom position by rapidly recognizing information on a zoom position and making a focus function follow up the operation of a zoom function especially in taking a moving picture. SOLUTION: Since the information on the zoom position in a 1st MPU 50 is transmitted to a 2nd MPU 52 from parallel ports 50P and 52P, the operation control of an AF function based on the zoom position is rapidly performed in the 2nd MPU 52. By dividing a zoom moving range into four and fixing one pan-focus position in each range, the pan-focus position is made to follow up any position of zoom operation and follow up the picture of a through operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera provided with a zoom function and an autofocus function and capable of photographing a subject as a digital image.

[0002]

2. Description of the Related Art With the development of digital technology, with the advent of digital cameras in the photographic industry, instead of ordinary cameras that take pictures by directly exposing them to silver halide films,
2. Description of the Related Art Digital cameras that capture an image of a subject using a solid-state imaging device such as a CCD and store the captured digital image data in a memory are increasing. The stored image data is
By performing image processing using image software such as a personal computer, it is possible to output an image using, for example, an inkjet printer or a laser printer. Further, by changing the color system, image data for exposing a silver halide film to a laser beam can be created.

That is, in a digital camera, higher resolution (multiple pixels) is advanced, and an image quality almost equal to that of a conventional silver halide photograph can be obtained.

[0004] In the case of a digital camera, an LCD monitor for adjusting the angle of view is mounted, and the through image on the LCD monitor is rough during a through operation (when the digital camera is moved to adjust the angle of view). May be video.

[0005] This is due to the difference in the depth of focus of the subject.
This is because the position of the focus lens deviates (is out of range) from the pan focus position. For this reason, if the focus lens position is made to follow the pan focus position, it is possible to suppress a decrease in the image quality of the through image.

Incidentally, in a digital camera having a zoom function, a change in the pan focus position with respect to the operation of the zoom function has a tracking curve as described in JP-A-6-121212. Since this tracking curve is not linear in characteristics, it is very difficult to control the position of the focus lens to the pan focus position at each zoom position in digital cameras with zoom functions. The more digital cameras you have, the more complicated the control becomes.

Usually, a digital camera does not have a CPU (MPU) capable of responding to the above control at high speed.
Further, there are many structures in which two or more MPUs (MPU1, MPU2) are connected by serial communication. MPU1
Is mainly responsible for control related to system control such as power management, key input, and the like.
Responsible for camera control such as playback. Regarding the lens control, the MPU 1 is in charge of the control of the zoom function, and the MPU 2 is in charge of the control of the focus function.

For this reason, when the focus is adjusted at an arbitrary zoom position, after the operation control of the zoom function is completed in the MPU 1, the zoom position information is transmitted to the MPU 2 by serial communication, and the MPU 2 receives the zoom position information based on the received zoom position information. This is a procedure of executing control for focusing.

Although the response speed is sufficient in view of the original function of photographing a still image in a digital camera, when this is used for moving image photographing, first, the focus is adjusted to the focus search home position at the current zoom position.
Since the operation of the autofocus function is started, it takes a long time to search for a focus position, and there is a problem that a focus position cannot be obtained with good response for all consecutive image frames.

[0010]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention recognizes zoom position information quickly, particularly in moving image shooting, and causes the focus function to follow the operation of the zoom function. It is an object to obtain a digital camera that can maintain a pan focus position.

[0011]

According to a first aspect of the present invention, there is provided a digital camera provided with a zoom function and an autofocus function, wherein the autofocus function is performed based on a continuously variable zoom position. Is operated, and a control means for following the pan focus position at each zoom position or a position approximate thereto is provided.

According to the first aspect of the present invention, the zoom function includes, for example, a TELE function button and a WIDE function button, and by continuously operating one of them, the magnification changes steplessly. If the auto focus function is operated during the continuous operation to follow the pan focus position at each zoom position or a position close to the pan focus position, so-called out-of-focus is not generated particularly when shooting a moving image. . Further, it is possible to simplify the operation control of the autofocus function (focusing) thereafter.

According to a second aspect of the present invention, there is provided a digital camera provided with a zoom function and an autofocus function, wherein a stepless operation range by the zoom function is divided into a plurality of sections, and a pan within each of the divided sections is defined. It is characterized by having a control means for causing the autofocus function to follow a focus position or a position approximate thereto in a plurality of steps.

According to the second aspect of the present invention, a somewhat rough control is performed with respect to the first aspect of the present invention. In other words, in the first aspect, any zoom position is positioned almost at the pan focus position, but this is slightly roughened. More specifically, the operation range of the zoom function is divided into a plurality of sections, and the operation of the auto focus function is controlled so that the pan position is at or close to the pan focus position at the zoom position within the divided range. Responsiveness for focusing is improved as compared to operating the autofocus function after the operation of the function ends.

According to a third aspect of the present invention, in the second aspect of the present invention, the number of divided ranges of the zoom function is set to be larger than the number of steps of the autofocus function. And

According to the third aspect of the present invention, by setting the number of divided ranges of the zoom function larger than the number of steps of the autofocus function, the load on the autofocus function can be minimized. it can.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the control means includes control of the operation of the zoom function, and is mainly used for system management. A first control unit that performs control, a second control unit that includes control of operation of the focus function, and mainly performs control relating to photographing and recording, and the first control unit and the second control unit. A serial communication port for transmitting and receiving signals between the first control unit and a zoom position information dedicated port for transmitting the zoom position information based on the operation of the zoom function of the first control unit to the second control unit. It is characterized by being constituted.

According to the fourth aspect of the present invention, only the zoom position information is sent from the first control unit to the second control unit through a dedicated port separately from other data signals, so that the zoom control is performed. Even if the function and the auto-focus function are controlled by different control units, the auto-focus function follows the predetermined zoom position (or range) with good responsiveness and becomes the pan-focus position or a position close to the pan-focus position. Can work.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the zoom position information dedicated port is a general-purpose parallel port.

According to the invention described in claim 5, a general-purpose parallel port can be used as the port dedicated to zoom position information. In this case, the number of divisions (the number of zoom ranges) in the zoom function may be determined based on the number of ports. For example, in the case of two ports, the advantage of the parallel port can be utilized by dividing into four bits, that is, by dividing into four, and a quick response is possible.

According to a sixth aspect of the present invention, in the first aspect of the present invention, there is further provided a display means for displaying a through image for determining an angle of view. Is characterized by reflecting a follow-up operation to a pan-focus position according to the operation of the zoom function in the auto-focus function.

According to the sixth aspect of the present invention, when determining the angle of view for photographing while looking at the display means, if the camera always follows the pan focus position when the zoom mechanism is operated, a shutter chance is obtained. An appropriate angle of view can be determined without missing.

[0023]

FIG. 1 shows a digital camera 10 according to an embodiment of the present invention.

As shown in FIGS. 1A and 1B, the main body 12 of the digital camera 10 is substantially box-shaped, and a projection (gripping portion) for facilitating the grip of the main body 12 is provided on the left side when viewed from the front. )
Is formed. A lens 14 is attached to the center of the front side of the main body 12. Above the lens 14 of the main body 12, an optical viewfinder 16 for a user to visually check a photographing range and the like is provided. A strobe 18 for emitting auxiliary light is attached.

On the upper surface of the main body 12, a power switch 20 is provided on the right side when viewed from the front, and a shutter button 22 is provided on the left side (a position corresponding to the grip portion). The right side is provided with a slot 24 in which a memory card (not shown) can be inserted.

Further, below the strobe 18, an AC adapter connection port 28 for connecting to obtain power from an AC power supply is provided.
Is provided so that power can be supplied to the digital camera 10 from an AC power supply.

Further, as shown in FIG.
A color display 26 (which may be a monochrome display) made of a transmissive liquid crystal (which may be a transflective liquid crystal) is provided on the back surface of the device. It is provided with a configuration. The display 26 has the function of the finder 16.

On the rear side of the main body 12, on the left side as viewed, a menu (MENU) switch 36, an execution / screen switching (E)
X / VIEW CHG) switch 38 and selection (S
An ELECT) switch 42 is provided, and a cancel (CANCEL) is provided above the display 26.
A switch 64 is provided. The selection switch 4
Reference numeral 2 denotes a switch for selecting a mode such as a menu screen displayed by pressing the menu switch 36, and an execution / screen switch 38 is a switch for executing the selected mode or the like. The switch 64 is a switch for canceling various modes and the like.

FIG. 2 is a block diagram showing a photographic image processing control mainly in the drive control system of the lens 14 in the digital camera 10.

That is, the lens 14 has an auto focus (AF) function and a zoom function (focal length variable lens).
And the zoom mechanism of the lens 14 is the first MPU
The AF function is controlled by the second MPU 52.

An area CCD sensor 46 is disposed at a position corresponding to the focal position of the lens 14 inside the main body 12, and the light reflected on the subject and incident on the lens 14 is incident on the light receiving surface of the imaging device 46. It is imaged. The imaging device 46 is driven at a timing synchronized with a timing signal generated by a timing generation circuit (not shown), and outputs an image signal (a light receiving amount in each of a large number of photoelectric conversion cells arranged in a matrix on a light receiving surface). Is output.

Although not shown, a shutter and a diaphragm are arranged between the lens 14 and the area CCD sensor 46. The light emission of the strobe 18 (see FIG. 1) is controlled in synchronization with the shutter when it is detected that the illuminance is low or when the user instructs light emission.

The signal output terminal of the imaging device 46 has a TG
(Timing generator), GC (gain control), and A / D (analog / digital) converter. In the signal processing unit 54,
The image signal output from the area CCD sensor 46 is amplified, and white balance and the like are corrected for the amplified image signal. The image signal output from the signal processing unit 54 is converted into digital image data by an A / D converter, and is converted into a DSP (Digital Signal Processor).
56. The DSP 54 performs various processes such as color correction, γ correction, and Y / C conversion on the input image data. The image data output from the signal processing unit 54 is
It is temporarily stored in a memory such as a RAM, and is also stored in the IC card 56 inserted in the slot 24.

Here, the first MPU 50 is in charge of control relating to system control such as power management and key input, and operation control of the zoom function. Also, the second MP
U52 is in charge of control relating to camera photographing, such as photographing, recording an image, and displaying an image on the display 26, and operation control of the AF function.

The first MPU 50 and the second MPU 52 have a special code 5 between the serial ports 50S and 52S.
8 for transmitting and receiving signals by serial communication.

By the way, apart from the connection of the code 58 for performing the serial communication, the general-purpose barrel ports 50P, 52P
The P is connected by a cord 60. This parallel port has connection terminals of about 25 to 50 pins, of which two pins are connected from the first MPU 50 to the second MPU.
It is applied for transmitting an operation position signal of the zoom function to U52. As a result, the zoom position in the zoom function can be changed to the second MPU more quickly than in the serial communication.
Recognition is possible at 52.

In the second MPU 52, based on the zoom position signal input from the parallel port 52P, A
The operation of the F function is controlled.

This operation is controlled by the above-mentioned two pins (two bits).
There are prepared four types of operation control corresponding to the representable number. That is, the zoom operation range is divided into four, and one pan focus position is set in each range.

Thus, when the zoom function is activated, the AF function is activated every time a break point between the ranges is straddled.
The pan focus position is set in advance in the range. Therefore, focusing can be performed quickly and with good response even after the through operation, and focusing by the AF operation after the zoom position is determined can be performed in a relatively short search range.

It should be noted that the digital camera 10 can shoot a moving image in addition to a still image. The shooting of a moving image is selected by operating the selection switch 42. Basically, when shooting a moving image, shooting of a still image is continuously performed. However, a limited frame memory is prepared in advance, and shooting of a moving image for a time corresponding to the capacity of the frame memory can be performed. It is possible. Normal moving image shooting time ranges from several seconds to several minutes. At the time of capturing a moving image, the captured image is displayed on the display 26 in the same manner as the through image.

The operation of this embodiment will be described below.

First, the operation control of the AF function based on the zoom operation position will be described with reference to the flowchart of FIG.

First, at step 100, driving of the zoom function is started, and then at step 102, it is determined whether or not the state (0 or 1) of the 2-bit state (ZPOS1, ZPOS2) of the parallel port has changed. .

[0044]

[Table 1]

These ZPOS1 and ZPOS2 are predetermined as shown in Table 1. That is, ZPOS1,
When ZPOS2 is 0,0, the distance is from collapsed (Z0) to Z2. When ZPOS2 is 1,0, the distance is from Z3 to Z4.
In the case of (1), Z5 is set to Z6, and in the case of 1, 1, Z7 is set to Z10. A picture in which four pan focus positions of the same value are determined corresponding to the four divided ranges.

If an affirmative determination is made in step 102, the process proceeds to step 104, where the 2-bit state (ZPOS) is set.
1, the state of the ZPOS2), the current zoom position is determined to be in any of the four divided operating ranges, and then in step 106, the AF function is operated up to the pan focus position corresponding to the determined range. Move to step 108.

If a negative determination is made in step 102, it is determined that the zoom position has been moved within the same range, and the process proceeds to step 108.

In step 108, it is determined whether or not the zoom drive has been completed. If the determination is negative, the process proceeds to step 102 and the above steps are repeated.

If an affirmative determination is made in step 108, the process proceeds to step 110, in which the zoom position of the 10 positions is determined by serial communication as in the conventional case, and then the AF function is operated in step 112, and the determined position is determined. Move to the pan focus position corresponding to
Focusing ends.

[0050]

[Table 2]

FIG. 4 and Table 1 show that the operation position of the zoom function that is changed steplessly is assumed to be ten positions (Z1 to Z1).
0) (11 positions including the retracted state (Z0)), and the pan focus position (the number of pulses from the focus home position) at each zoom position when the pan focus position is set to 4 positions. For reference, the number corresponding to the divided zoom position, that is, the pan focus position (pulse number) of 10 positions is also shown. In addition, two types are shown, in which the focus of the subject is infinite and when the focus is 80 cm.

As shown in FIG. 4, in the focal length characteristic (tracking curve) at the zoom operation position, in the four-position pan focus position control that changes stepwise, the focal position is almost at each zoom position. You can see that there is.

Therefore, in the subsequent 10-position focus position control (conventional control), the position can be quickly and easily adjusted because the target position is approaching.

As described above, in the present embodiment, the first M
The PU 50 and the second MPU 52 are connected to the serial port 50
S, 52S, as well as the parallel ports 50P, 52P
P are connected, and the zoom position information in the first MPU 50 is transmitted from the parallel ports 50P and 52P to the second MPU 52, so that the second MPU 5
In 2, the operation of the AF function can be quickly controlled based on the zoom position. Therefore, if the zoom movement range is divided into four parts, and one pan focus position is determined for each range, the pan focus position can follow any of the zoom operation positions, and follows the image of the through operation. it can. Further, the subsequent focusing operation becomes quick and easy. In addition, for example, even if a large zoom operation is performed during the operation shooting, the focus of each image frame can be substantially adjusted.

Since the movement control to the pan focus position is not necessary except for the output of a through image and the shooting of a moving image, the parallel ports 50P and 52P (ZPOS) are not required.
1, ZPOS2) can be used as another information port.

For example, when transferring an image stored in a card by USB communication, display means (L
ED) must be used. During such processing, the imaging system is in the power-off state.

Since the display means is also used for various warnings, the first M which is in charge of the power supply voltage and the key operation is provided.
Controlling with the PU 50 is more advantageous. For this reason, when a common display is used, it is necessary to transmit the information from the second MPU 52 to the first MPU 50 when indicating that the card is being accessed.

At this time, the parallel port ZPOS1,
Use of ZPOS2 enables quick information transmission.

[0059]

As described above, the digital camera according to the present invention quickly recognizes zoom position information, particularly in moving image shooting, causes the focus function to follow the operation of the zoom function, and at least pans at an arbitrary zoom position. It has an excellent effect that the focus position can be maintained.

[Brief description of the drawings]

FIG. 1 is a digital camera according to an embodiment,
(A) is a perspective view seen from the front, (B) is a perspective view seen from the back.

FIG. 2 is a control block diagram of the digital camera according to the present embodiment.

FIG. 3 is a diagram illustrating a case where a panning focus position according to a zoom operation is set to A;
It is a flowchart which shows the movement operation control routine by F function.

FIG. 4 is a characteristic diagram of a pan focus position at a zoom position divided into ten parts (excluding a retracted part).

[Explanation of symbols]

 Reference Signs List 10 digital camera 14 lens 26 display 42 selection switch 46 area CCD sensor 50 first MPU (MPU1) 52 second MPU (MPU2) 50P, 52P parallel port

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/232 G03B 3/00 A

Claims (6)

[Claims] 1. A digital camera provided with a zoom function and an auto focus function, wherein the auto focus function is operated based on a zoom position that changes steplessly, and a pan focus position at each zoom position or A digital camera having control means for following an approximate position. 2. A digital camera provided with a zoom function and an autofocus function, wherein a stepless operation range by the zoom function is divided into a plurality of sections.
A digital camera, comprising: control means for causing the autofocus function to follow a pan focus position or a position approximate thereto in a plurality of divided ranges in a plurality of steps. 3. The digital camera according to claim 2, wherein the number of divided ranges of the zoom function is set to be larger than the number of steps of the autofocus function. 4. The control means includes: a first control unit that mainly controls system management, including control of operation of the zoom function; and control of operation of the focus function. A second control unit that controls recording, a serial communication port that transmits and receives signals between the first control unit and the second control unit, and a zoom function of the first control unit. The digital camera according to any one of claims 1 to 3, further comprising a zoom position information dedicated port for transmitting the zoom position information based on the second control unit. . 5. The digital camera according to claim 4, wherein the dedicated port for zoom position information is a general-purpose parallel port. 6. A display device for displaying a through image for determining an angle of view, wherein the display of the display device reflects a follow-up operation to a pan-focus position according to an operation of a zoom function in the auto-focus function. The digital camera according to claim 1, wherein the digital camera is operated.