JPH11155095A - Auto-focusing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a driving time by outputting an AF evaluating value which is obtained by means of integrating the high frequency component of luminance data in digital image data, sampling the AF evaluating value obtained by means of an AF evaluating means while moving the position of a focus lens system, focusing by means of its result and driving the focus lens system to a focusing position. SOLUTION: When the focusing position does not exist in a photographing range, the sampling of the AF evaluating value within the range of a macro- photographing distance is executed. An output becomes off without an input when the enable signal of a self circuit is adopted as 'L' in a focus driver 131 and a zoom driver 133 and the output becomes the one for causing two phase energizing change when the enable signal is adopted as 'H'. A pulse becomes the one with a longer enable time in order of a wide operation, a mean operation and a tele-operation at the time of AF execution so that a focusing operation is executed at high speed by the wide operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an autofocus device, and more particularly, to an autofocus device used for a digital camera or a digital video camera.

[0002]

2. Description of the Related Art Focus adjustment methods used in an autofocus digital camera include a method of extending the entire photographic lens and a method of extending a part of the photographic lens.

For example, in an automatic focusing camera described in Japanese Patent Application Laid-Open No. 1-059311, the position on the optical axis of an image plane where a subject is imaged through a photographing lens, and the position on the optical axis of a film surface are described. The amount of defocus is detected by the detecting means, the driving amount of the photographing lens corresponding to the amount of defocus is stored in the storage means in a table format, and the amount of driving of the imaging lens corresponding to the amount of defocus outputted from the detecting means is selected. And the drive control means drives and controls the focusing lens group based on the photographing lens drive amount output from the selection means. Shorten the time to focus.

In the focus detecting device described in Japanese Patent Application Laid-Open No. 1-187521, a lens for photographing, focus detecting means for detecting a focus state of the lens, lens driving means for driving the lens 1, a focus detecting means, A focus detection inability determining means for determining whether or not focus detection is impossible by the means; and a lens driving means driving the lens between the scanning limit positions when the focus detection inability determining means determines that the focus detection is impossible. A lens scanning control unit for performing a focus detection operation by the focus detection unit; and a lens end position Nmax.
Output means for outputting information about the defocus amount DFa which can be detected by the focus detection means, output means for outputting information about the defocus amount DFa which can be detected by the focus detection means, and the defocus amount up to the end position of the lens. When it is determined that focus detection is impossible by providing the scanning limit position (Nmax−DFa × K) and the scanning limit position determining means for determining the DFa × K so that the defocus amount is within the focus detectable defocus amount DFa. In addition, by limiting the range in which the focus detection operation is performed while moving the lens to a narrow range, the time until it is determined that focus detection cannot be performed is reduced.

The auto-focusing device described in Japanese Patent Application Laid-Open No. Sho 61-262382 uses a system in which a subject image is scanned and converted into a video signal by an area-type self-scanning solid-state imaging device having a rectangular light receiving area. 2. Description of the Related Art In a video camera or the like that performs an automatic focusing device, a focus detection unit for obtaining a focus detection signal from a video signal and a lens group related to focus adjustment in an imaging lens system are positively aligned on an optical axis. A driving unit for moving the predetermined distance Δx in one step in the opposite direction; and a control unit. The control unit moves the lens groups in a predetermined manner by the driving unit, and moves the lens groups by Δx with each other. The focus detection signals at three shifted adjacent positions are obtained, and the amount and direction of movement of the lens group are determined based on the magnitude relationship between these three focus detection signals. A process of determining a moving direction and performing a necessary displacement on the lens group is performed as necessary, and a focusing function for moving the lens group to a position where a focus detection signal is maximum, and focusing on the lens group is performed. A focus process restart function for generating a focus detection signal even after being located at the position where the detection signal is the maximum and for causing the focus function to function again when a change in the focus detection signal exceeds a certain value. Thus, the direction of the lens position can be reliably determined, and malfunction is prevented.

[0006]

By the way, a lens generally called a zoom lens is a lens whose shooting distance does not change due to zooming. On the other hand, a varifocal lens is a lens whose shooting distance changes due to zooming. That is, the varifocal lens needs to drive the focus lens in order to prevent blurring due to zooming.

However, even with a lens called a zoom lens, it can be said that there is hardly any lens whose photographing distance does not completely change due to zooming. Is at a level that is perfectly acceptable. This problem is recognized as a problem that the number of lens groups and the number of components increase as the magnification of the zoom lens increases, the zoom lens cam for setting the lens group interval becomes complicated, and processing accuracy increases.

Therefore, a range widened to include the position of the focus lens at infinity and the closest position at any zoom position is set as the movement range of the focus lens. However,
An AF evaluation value is sampled while moving the focus lens system, focusing is determined based on the sampling result, and the focus lens system is driven to a focus position. There was a problem that it takes time until.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an autofocus apparatus which shortens the time required to drive a focus lens system to a focus position and shortens the AF execution time. And

[0010]

According to a first aspect of the present invention, there is provided an autofocus apparatus for converting subject light through a focus lens system and a zoom lens system into an electric signal and converting the signal into image data. An image sensor for outputting, A / D converting means for A / D converting the image data to a digital image signal, and outputting an AF evaluation value obtained by integrating a high frequency component of luminance data of the digital image data. AF evaluation means and A obtained by the AF evaluation means while moving the position of the focus lens system.
A sampling means for sampling an F evaluation value, a focus driving means for judging focusing based on a sampling result of the AF evaluation value of the sampling means, and driving the focus lens system to a focus position; and the sampling means, The amount of movement of the focus lens system at each sampling when sampling the AF evaluation value is
Moving amount changing means for changing according to the position of the zoom lens system.

According to a second aspect of the present invention, there is provided an auto-focusing device which converts an object light passed through a focus lens system into an electric signal and outputs the same as image data, and an A / D converter which converts the image data into a digital signal. A / D conversion means for converting into an image signal, AF evaluation means for outputting an AF evaluation value obtained by integrating a high frequency component of luminance data of digital image data, and the AF while moving the position of the focus lens system. Sampling means for sampling the AF evaluation value obtained by the evaluation means, focus driving means for determining focus based on the sampling result of the AF evaluation value of the sampling means, and driving the focus lens system to a focus position; The sampling means performs sampling at the time of each sampling when sampling the AF evaluation value. The amount of movement of Kasurenzu system, in which and a moving amount changing means for changing in accordance with the position of the Fukasu lens system.

According to a third aspect of the present invention, there is provided an auto-focusing device for converting an object light passed through a focus lens system and a zoom lens system into an electric signal and outputting the electric signal as image data; A / D conversion means for converting the digital image data into a digital image signal, and an A / D converter obtained by integrating a high frequency component of luminance data of the digital image data.
AF evaluation means for outputting an F evaluation value, sampling means for sampling an AF evaluation value obtained by the AF evaluation means while moving the position of the focus lens system, and a sampling result of the AF evaluation value by the sampling means Focus driving means for judging focus by driving, and driving the focus lens system to a focus position;
A full-range sampling focus system movement setting unit that always executes the sampling of the AF evaluation value regardless of the sampling result of the F evaluation value, and stops the sampling of the AF evaluation value when focusing is determined based on the sampling result of the AF evaluation value. Macro system sampling focus lens system movement setting means, and movement amount changing means for changing the entire width of the movement amount of the focus lens system of the whole area sampling focus lens system movement setting means according to the position of the zoom lens system, It is provided with.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of a digital camera to which the autofocus device according to the present embodiment is applied. In FIG. 1, reference numeral 100 denotes a digital camera. The digital camera 100 includes a lens system 101, a mechanical mechanism 102 including an aperture / filter unit, a CCD 103, and a CDS.
Circuit 104, variable gain amplifier (AGC amplifier) 105,
A / D converter 106, IPP 107, DCT 108, coder 109, MCC 110, DRAM 111, PC card interface 112, CPU 121, display unit 12
2, operation unit 123, SG (control signal generation) unit 126, strobe device 127, battery 128, DC-DC converter 129, EEPROM 130, focus driver 131, pulse motor 132, zoom driver 133,
It comprises a pulse motor 134 and a motor driver 135. Also, the PC card interface 11
2, a detachable PC card 150 is connected.

The lens unit comprises a mechanical mechanism 102 including a lens 101 system, a diaphragm and a filter section, and the mechanical shutter of the mechanical mechanism 102 simultaneously exposes two fields. The lens system 101 is formed of, for example, a varifocal lens, and includes a focus lens system 101a and a zoom lens system 101b.

The focus driver 131 is connected to the CPU 12
1 according to the control signal supplied from the
2 to move the focus lens system 101a in the optical axis direction. The zoom driver 131 includes a CPU 121
Pulse motor 132 according to the control signal supplied from
To move the zoom lens system 101b in the optical axis direction. In addition, the motor driver 135 includes the CPU 121
The mechanical mechanism 102 is driven in accordance with a control signal supplied from the controller, and for example, an aperture value of the aperture is set.

The CCD (Charge Coupled Device) 103 converts an image input through a lens unit into an electric signal (analog image data). The CDS (correlated double sampling) circuit 104 is a circuit for reducing noise in the CCD type image pickup device.

The AGC amplifier 105 corrects the level of the signal that has been correlated double-sampled by the CDS circuit 104. The gain of the AGC amplifier 105 is determined by the CPU 1
21 allows the setting data (control voltage) to be transferred to the AGC amplifier 1 via a D / A converter built in the CPU 121.
05 is set. A / D
The converter 106 converts analog image data input from the CCD 103 via the AGC amplifier 105 into digital image data. That is, the output signal of the CCD 103 is converted into a digital signal at the optimum sampling frequency (for example, an integer multiple of the subcarrier frequency of the NTSC signal) by the A / D converter 105 via the CDS circuit 104 and the AGC amplifier 105. Is done.

The digital signal processor IPP
(Image Pre-Processor) 107, DCT (Discrete Cos)
ine Transform) 108 and coder (Huffman Enco
A der / Decoder) 109 performs various processing, correction, and data processing for image compression / decompression on the digital image data input from the A / D converter 106 by dividing the digital image data into color difference (Cb, Cr) and luminance (Y). Apply. Image compression / decompression unit 107
Performs, for example, orthogonal transformation, which is a process of JPEG-compliant image compression / decompression, and Huffman encoding / decoding, which is a process of JPEG-compliant image compression / decompression.

Further, an MCC (Memory Card Controlle)
An r) 110 temporarily stores the compressed image and records the image on the PC card 150 via the PC card interface 112 or reads the image from the PC card 150.

The CPU 121 controls all operations inside the digital camera according to an instruction from the operation unit 123 or an external operation instruction from a remote controller (not shown) using the RAM as a work area according to a program stored in the ROM. . Specifically, the CPU 121 performs an imaging operation, an automatic exposure (AE) operation, an automatic white balance (AWB)
It controls the adjustment operation and the AF operation.

The camera power source is a battery 128, for example, a NiCd, nickel hydrogen, lithium battery, etc.
The signal is input to the C-DC converter 129 and supplied to the inside of the digital camera.

The display unit 122 is implemented by an LCD, LED, EL, or the like, and displays photographed digital image data, decompressed recorded image data, and the like. Operation unit 1
Reference numeral 23 includes buttons for externally performing function selection, shooting instructions, and other various settings. EEPRO
In M130, adjustment data and the like used when the CPU 121 controls the operation of the digital camera are written.

The digital camera 100 (CPU 1
21) converts image data obtained by imaging a subject into a PC
Recording Mode for Recording on Card 150 and PC Card 15
The display mode includes a display mode for displaying image data recorded at 0, a monitoring mode for directly displaying captured image data on the display unit 122, and the like.

FIG. 3 shows a control voltage and an output gain (Measured) of the AGC amplifier 105.
FIG. 2, the horizontal axis represents the control voltage (Control Vol.) Of the AGC amplifier 105.
stage, and the vertical axis indicates the output gain (Me
asured Gain). The data of the characteristic curve shown in FIG. 2 is digitized and stored in the EEPROM 130.

FIG. 2 is a diagram showing an example of a specific configuration of the IPP 107. As shown in FIG. 2, the IPP 107 separates the digital image data input from the A / D converter 106 into R, G, and B color components.
A signal interpolating unit 1072 for interpolating the separated R, G, B image data, a pedestal adjusting unit 1073 for adjusting the black level of each of the R, G, B image data, and each of the R, B images A white balance adjustment unit 1074 for adjusting the white level of the data; a digital gain adjustment unit 1075 for correcting each of the R, G, and B image data with a gain set by the CPU 121; a gamma conversion unit 1076 for performing γ conversion, a matrix unit 1077 for separating RGB image data into color difference signals (Cb, Cr) and a luminance signal (Y), a color difference signal (Cb, Cr), and a luminance signal (Y) And a video signal processing unit 1078 that creates a video signal based on the video signal and outputs the video signal to the display unit 122.

The IPP 107 further includes a Y operation unit 1079 for detecting luminance data (Y) of the image data after the pedestal adjustment by the pedestal adjustment unit 1073, and a Y operation unit 1
079, a BPF 1080 that passes only a predetermined frequency component of the luminance data (Y) detected, and an integrated value of the luminance data (Y) that has passed through the BPF 1080 is used as an AF evaluation value as C value.
An AF evaluation value circuit 1081 that outputs to the PU 121, an AE evaluation value circuit 1082 that outputs a digital count value corresponding to the luminance data (Y) detected by the Y operation unit 1079 to the CPU 121 as an AE evaluation value, and a digital gain adjustment unit 1075 A Y operation unit 1083 for detecting luminance data (Y) of each of R, G, and B image data after gain adjustment by
The luminance data (Y) of each color detected by the Y operation unit 1083 is counted, and the CPU calculates the AWB evaluation value of each color.
AWB evaluation value circuit 1084 for outputting to CPU 121 and CPU
CPU I / F 108 which is an interface with the I / F 121
5 and DT which is an interface with DCT 108
A CTI / F1086 and the like are provided.

Here, each control will be described. In the AE control, the shutter speed and the AGC are controlled so that the AE evaluation value becomes a reference value. In this embodiment,
As an example, a description will be given assuming that the aperture is fixed (F4; Av4).

In the AF control, after a shutter speed and a gain are set, an AFM (pulse motor) is driven by a specified pulse during a 1 Vd period. During the specified pulse driving, the digital video signal obtained in the IPP is processed to obtain a luminance signal. The AF evaluation value is obtained by integrating the high frequency component from the luminance signal by the filter means. This AF evaluation value peak is focused.

In the zoom control, the current focus position is changed from a setting value "fp far calc" (infinity) to a setting value "fp near calc"(closest;
The position (distance) up to about 0.2 m) can be determined by the ratio. The focus position is set to “fp far def” and “fp
The lens is driven to a focus position having the same ratio from "near def", and the focus shift due to the zoom of the varifocal lens is corrected.

Next, each set value which is an adjustment value will be described. FIG. 6 is a diagram for explaining setting values. As shown in FIG. 6, autofocus is performed using a varifocal lens having nine zoom steps (positions) from 00 to 08. Further, the shooting distance range is from infinity to about 0.2 m, but is set to about 0.01 m only for wide.

In the table shown in FIG. 6, "ccdaf dr" is set as six types of set values for each zoom step.
v data "," fp far def "," fp
near def "," fp far calc ",
“Fp near calc” and “nml smp” are associated with each other. Note that each set value in FIG. 6 is displayed in hexadecimal.

Here, "ccdaf drv data"
“a” indicates the movement amount (number of pulses) of the focus lens system for each sampling when sampling the AF evaluation value. “Fp far def” indicates the AF evaluation value sampling start position at each zoom step, and a difference based on the position of the number of focus extension pulses “fp inf def” is input as data.

“Fp near def” indicates the AF evaluation value sampling end position at each zoom step, and the number of focus extension pulses “fp inf de”
The difference based on the position of “f” is input as data. “Fp far calc” indicates an infinite position at each zoom step, and a difference based on the position of the number of focus extension pulses “fp inf def” is input as data.

"Fp near calc" indicates a 0.2 m position in each zoom step, and a difference based on the position of the number of focus extension pulses "fp inf def" is input as data. "Nml sm
“p” indicates the number of samplings for moving the entire-area sampling focus lens system that always performs sampling of the AF evaluation value regardless of the sampling result of the AF evaluation value.

Note that "fp inf def" indicates the number of focus extension pulses from the mechanical end of the infinity side of the focus to the start of wide AF evaluation value sampling.

Next, the operation will be described. FIG. 5 is a flowchart illustrating a setting operation for performing an autofocus operation, and FIG. 4 is a flowchart illustrating an autofocus operation.

In FIG. 5, fp far init =
Focus feeding pulse number (fpinf def)-
AF evaluation value sampling start position (fp far
def [zoom]), fp near init = number of focus delivery pulses (fp inf def) +
AF evaluation value sampling end position (fp near
def [zoom]), fp home = (fp fa
r init) − (fp home def), and nml smp def = nml smp [zoo
m]. Here, zoom is a position of 9 zoom steps. When zoom = 0, the zoom becomes “wide”, and when zoom = 4, the zoom becomes “mean”.
When m = 8, it becomes "tele".

In the operation shown in FIG. 5, first, zoom reset is performed by adjusting the zoom position and the number of zoom drive pulses, and then focus reset is performed by adjusting the focus position and the number of focus drive pulses. The zoom reset and the focus reset are performed by driving each to the mechanical end.

The position after driving with the number of pulses equal to or greater than the number of pulses driving to the mechanical end is determined as a specified pulse number position. Here, in the case of focus, f is set at the mechanical end on the near side.
pmax = 205 pulses. The data of the last pulse output when driving to the mechanical end is fp home.
The state is set at the time of adjustment. Subsequently, the focus is set to the ordinary focus position (approximately 2.5 m), and further zooming is performed.

Subsequently, the operation shown in FIG. 4 is started. The operation mode shown in FIG. 4 is an autofocus mode. In the case of auto focus, first, AF initial setting (ccdaf init set) is executed (step S1), and the first release is operated. At this time, the normal focus position at the set zoom point (approximately 2.5
m) is calculated from the adjustment value, and the AF operation is performed. Then, AF
An AE for use is set (ccdafae set) (step S2).

Then, when the process proceeds to step S3, the focus is shifted to the home position HP (fp home).
e). In the following step S4, the focus is driven to the initial position INIT (fp far init). Thus, the focus is on the home position HP
Is driven to the initial position INIT, the backlash (fpbrash = 8 (pulse)) can be removed.

Then, the process shifts to step S5.
Focus driving at the time of AF evaluation value sampling is performed in synchronization with the vertical synchronization signal Vd. At this time, the focus is the movement amount (ccda) of the focus lens system for each sampling.
Drive by f drv data). At this time, regardless of the AF evaluation value (information such as the peak), the focus drive is performed at the near position (Am for nml smp).
Until the F evaluation value is sampled, the focus drive amount is (ccdaf drv data) * (n
ml smp)). This is within the normal shooting distance range (from infinity to about 0.5 m).

Here, the peak position, the increase / decrease data of the AF evaluation value, and the like are calculated from the AF evaluation values sampled within the normal shooting distance range, and it is determined whether or not the in-focus position is within the normal shooting distance range. Is done. Even when focusing is performed within the macro shooting distance range, the focus lens is driven to the in-focus position after driving the focus from the in-focus position to a position for removing backlash.

Thereafter, the processing shifts to step S6.
In step S6, when the focus position is within the normal shooting distance range, sampling of the AF evaluation value is stopped,
After the focus is driven from the in-focus position to a position for removing the backlash, the focus is driven to the in-focus position.

If there is no in-focus position within the normal photographing distance range, sampling of the AF evaluation value within the macro photographing distance range (about 0.5 m to about 0.2 m) is performed (macro; fp). near init). However,
Within the macro shooting distance range, sampling of the AF evaluation value is stopped when a peak is detected.

Thereafter, the processing shifts to step S7.
In step S7, the focus drive is turned off (fcs
m off), this process ends.

Next, the relationship between the zoom position and the focus position will be described. FIG. 6 shows Z for focus position adjustment.
FIG. 8 is a diagram showing the F table, FIG. 8 is a diagram showing the ZF (zoom focus) table of FIG. 7 in a graph, and FIGS. 9 to 11 are timing charts showing the correspondence between the AF evaluation value sampling timing and the focus pulse motor drive timing. It is.

The ZF table is used when adjusting the focus position with respect to the zoom position. FIG.
The ZF table shown in FIG. 0, No. 1, No.
2 shows three examples. In each example, nine positions are allocated to the wide (W) end, the mean (M), and the tele (T) end with respect to two references of infinity and close proximity (for example, 20 cm). Each position is associated with a pulse number ZP and an adjustment value (f (mm)). This ZF table is stored and held in a ROM or the like.

In FIG. Infinity criterion A0-1 and closest criterion B0-1 are shown as graphs of No. 0.
Infinity criterion A1-1 and close criterion B1-1
And No. are shown. Infinity criterion A2-1
And the close reference B2-1. From the above graph, the number of pulses is lower when using the closest distance as the reference than when using infinity as the reference.

FIG. 9 shows that the vertical synchronizing signal Vd is 1/3
The timing chart regarding the 0 Hz (33 mS) NTSC is shown. FIG. 10 shows that Vd is 1/25 Hz (4
2 shows a timing chart related to a PAL (television: TV) of 0 mS). FIG. 11 is a timing chart for a PAL (liquid crystal: LCD) in which the vertical synchronization signal Vd is 1/36 Hz (28 mS).

According to the above timing chart, the pulse interval of the AF evaluation value sampling timing ST and the respective pulse intervals of the focus pulse motor drive timing WT (wide) and TT (tele) change with the spread of the pulse interval of the vertical synchronizing signal Vd. Is done. That is, when the NTSC of FIG. 9 is used as a reference, the pulse width becomes large because the PAL (TV) of FIG. 10 is 1/25 Hz, whereas the NTSC is 1/30 Hz. Therefore, PAL (TV) has a better AF evaluation value sampling ST and focus pulse motor drive timings WT and T than NTSC.
The pulse interval of T is widened.

On the other hand, referring to the NTSC shown in FIG.
In NTSC, the frequency is 1/30 Hz.
AL (LCD) becomes 1/36 Hz and the pulse width becomes smaller. Therefore, PAL (L
CD) makes the pulse interval between the AF evaluation value sampling ST and the focus pulse motor drive timings WT and TT narrower.

Next, the driver will be described in detail. FIG.
FIG. 13 is a circuit diagram showing a driver of a zoom pulse motor and a focus pulse motor, FIG. 13 is a diagram showing a truth table of a pulse motor drive IC, and FIGS. 6 is a timing chart showing a pulse waveform by simulation. In FIG. 12, the focus driver 13
1 and the zoom driver 133 define an input / output relationship according to the truth table shown in FIG.

According to the truth table shown in FIG. 13, the focus driver 131 and the zoom driver 133 have no input (IN1, 2) when the enable signal of their circuits is "L" (low). , The outputs (OUT1, 2, 3, 4) are turned off. On the other hand, when the enable signal is set to “H” (high), the outputs OUT1 to OUT4 are driven to be outputs in which two-phase excitation changes due to the logical relationship between the inputs IN1 and IN2. Here, FIG. 14, FIG. 15, and FIG.
The pulse waveforms at the time of wide operation, mean operation, and tele operation at the time of execution of F are shown. Comparing the above pulse waveforms, the enable time becomes longer in the order of wide, mean and tele, and the driving time of the driver becomes longer accordingly.

As described above, in this embodiment, when the FA evaluation value is sampled while moving the focus lens system, the amount of movement of the focus lens by one sampling is made larger on the wide side than on the tele side. This makes it possible to complete the focusing operation at the same shooting distance at a higher speed than in the telephoto mode.

Also, in this embodiment, by moving the focus lens by one sampling on the near side of the shooting distance to be larger than that on the infinity side, the focusing operation can be performed at high speed even when the shooting distance is short. Can be completed.

In the present embodiment, first, AF evaluation values are sampled within the normal photographing distance range, and if it is determined from the result that the peak is closer than the normal photographing distance range. Since the AF evaluation value is sampled only at a short distance, the AF execution time can be shortened within a normal shooting distance.

In the present embodiment, in the case of a vari-focal lens, the position of the focus lens system with respect to the shooting distance changes depending on the position of the zoom lens system. When performing sampling of the AF evaluation value,
By changing the position of the focus lens system according to the position of the zoom lens system, it is possible to shorten the AF execution time within a normal shooting distance.

[0060]

According to the first aspect of the present invention, there is provided an auto-focusing device which converts an object light through a focus lens system and a zoom lens system into an electric signal and outputs the same as image data, and A / D conversion of the image data. A / D conversion means for converting the image data into a digital image signal, AF evaluation means for outputting an AF evaluation value obtained by integrating a high-frequency component of the luminance data of the digital image data, and moving the position of the focus lens system. A obtained by the AF evaluation means
A sampling means for sampling an F evaluation value, a focus driving means for judging focusing based on a sampling result of the AF evaluation value of the sampling means, and driving the focus lens system to a focus position; and the sampling means, The amount of movement of the focus lens system at each sampling when sampling the AF evaluation value is
A moving amount changing means for changing the position of the zoom lens system in accordance with the position of the zoom lens system. Further, it is possible to achieve the AF accuracy and the AF execution time at the optimum AF evaluation value sampling at each zoom lens system position.

According to a second aspect of the present invention, there is provided an auto-focusing device, which converts an object light through a focus lens system into an electric signal and outputs the same as image data, and an A / D converter that converts the image data into a digital image. A to convert to signal
/ D conversion means and an AF for outputting an AF evaluation value obtained by integrating a high frequency component of luminance data of digital image data
Evaluation means, sampling means for sampling the AF evaluation value obtained by the AF evaluation means while moving the position of the focus lens system, and determining focusing by the sampling result of the AF evaluation value of the sampling means;
A focus driving unit that drives the focus lens system to the in-focus position and a sampling unit change a moving amount of the focus lens system at each sampling when sampling the AF evaluation value according to the position of the focus lens system. And moving amount changing means.
For example, at the time of flash shooting, it is possible to sample the AF evaluation value while moving the focus lens system in a unit of distance required for flash emission dimming control, and to set the flash AE to an appropriate exposure.

Further, an autofocus apparatus according to a third aspect of the present invention provides an image pickup device that converts subject light through a focus lens system and a zoom lens system into an electric signal and outputs the signal as image data, and A / D conversion of the image data. A / D conversion means for converting the image data into a digital image signal, AF evaluation means for outputting an AF evaluation value obtained by integrating a high-frequency component of the luminance data of the digital image data, and moving the position of the focus lens system. A sampling unit for sampling an AF evaluation value obtained by the AF evaluation unit, a focus driving unit for determining focusing based on a sampling result of the AF evaluation value of the sampling unit, and driving a focus lens system to a focusing position; A full-range sampling file that always executes AF evaluation value sampling regardless of the evaluation value sampling result A carcass-based mobile setting means, when it is determined focusing the sampling results of the AF evaluation value, A
The macro system sampling focus lens system movement setting means for stopping the sampling of the F evaluation value and the full width of the entire sampling focus lens system movement amount of the full area sampling focus lens system movement setting means are changed according to the position of the zoom lens system. Moving amount changing means, the AF evaluation value is sampled first within the normal shooting distance range, and it is determined from the result that the peak is closer than the normal shooting distance range. Since the AF evaluation value is sampled only at a short distance, the AF execution time can be shortened within a normal shooting distance.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a digital camera according to an embodiment.

FIG. 2 is a diagram illustrating an example of a specific configuration of the IPP of FIG. 1;

FIG. 3 shows a control voltage (Control V) of an AGC amplifier.
FIG. 6 is a diagram illustrating a relationship between the output gain (Measurement Gain) and the output gain (Measured Gain).

FIG. 4 is a flowchart illustrating an autofocus operation according to the embodiment.

FIG. 5 is a flowchart illustrating a setting operation for performing an autofocus operation according to the embodiment.

FIG. 6 is a diagram illustrating setting values according to the embodiment.

FIG. 7 is a diagram illustrating a ZF table used when adjusting a focus position with respect to a zoom position in the embodiment.

8 is a diagram showing the ZF table of FIG. 7 in a graph form.

FIG. 9 is a timing chart showing a correspondence relationship between AF evaluation value sampling timing and focus pulse motor driving timing in the embodiment.

FIG. 10 is a timing chart showing a correspondence relationship between AF evaluation value sampling timing and focus pulse motor driving timing in the embodiment.

FIG. 11 is a timing chart showing a correspondence relationship between AF evaluation value sampling timing and focus pulse motor driving timing in the embodiment.

FIG. 12 is a circuit diagram showing a driver of a zoom pulse motor and a focus pulse motor according to the embodiment.

13 is a diagram showing a truth table of a pulse motor drive IC in the driver shown in FIG. 11;

14 is a timing chart showing by simulation a pulse waveform at the time of executing auto focus in the driver shown in FIG. 12;

FIG. 15 is a timing chart showing, by simulation, a pulse waveform at the time of executing autofocus in the driver shown in FIG. 12;

16 is a timing chart showing, by simulation, a pulse waveform at the time of executing autofocus in the driver shown in FIG. 12;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Digital camera 101 Lens system 101 a Focus lens system 101 b Zoom lens system 102 Mechanical mechanism including autofocus 103 CCD (charge coupled device) 104 CDS (correlated double sampling) circuit 105 Variable gain amplifier (AGC amplifier) 106 A / D Converter 107 IPP (Image Pre-Processor) 108 DCT (Discrete Cosine Transform) 109 Coder (Huffman Encoder / Decoder) 110 MCC (Memory Card Controller) 111 RAM (Internal Memory) 112 PC Card Interface 121 CPU 122 Display Unit 123 Operation Unit 125 motor driver 126 SG unit 127 strobe 128 battery 129 DC-DC converter 130 EEPROM 131 focus driver 132 pulse motor 133 zoom driver 134 Motor 135 Motor driver 150 PC card 1071 Color separation unit 1072 Signal interpolation unit 1073 Pedestal adjustment unit 1074 White balance adjustment unit 1075 Digital gain adjustment unit 1076 Gamma conversion unit 1077 Matrix unit 1078 Video signal processing unit 1079 Y operation unit 1080 BPF 1081 AF evaluation Value circuit 1082 AE evaluation value circuit 1083 Y operation unit 1084 AWB evaluation value circuit 1085 CPU I / F 1086 DCTI / F 1075r, 1075g, 1075b Multiplier

Claims (3)

[Claims] 1. An image pickup device that converts subject light through a focus lens system and a zoom lens system into an electric signal and outputs it as image data, and an A / D converter that converts the image data into a digital image signal. / D conversion means, AF evaluation means for outputting an AF evaluation value obtained by integrating a high-frequency component of luminance data of digital image data, and A / D conversion means for moving the position of the focus lens system.
Sampling means for sampling an AF evaluation value obtained by an F evaluation means; focus driving means for determining focusing based on a sampling result of the AF evaluation value of the sampling means, and driving the focus lens system to a focus position; A moving amount changing unit that changes a moving amount of the focus lens system at each sampling when the AF evaluation value is sampled according to a position of the zoom lens system by the sampling unit. A featured autofocus device. 2. An image pickup device for converting subject light via a focus lens system into an electric signal and outputting the signal as image data, and A / D conversion means for A / D converting the image data and converting the image data into a digital image signal. AF evaluation means for outputting an AF evaluation value obtained by integrating a high-frequency component of luminance data of digital image data; and the AF while moving the position of the focus lens system.
Sampling means for sampling an AF evaluation value obtained by an F evaluation means; focus driving means for determining focusing based on a sampling result of the AF evaluation value of the sampling means, and driving the focus lens system to a focus position; A moving amount changing unit that changes a moving amount of the focus lens system at each sampling when the AF evaluation value is sampled according to a position of the focus lens system by the sampling unit. A featured autofocus device. 3. An image pickup device for converting subject light passing through a focus lens system and a zoom lens system into an electric signal and outputting it as image data, and an A / D converter for converting the image data into a digital image signal. / D conversion means, AF evaluation means for outputting an AF evaluation value obtained by integrating a high-frequency component of luminance data of digital image data, and A / D conversion means for moving the position of the focus lens system.
Sampling means for sampling an AF evaluation value obtained by an F evaluation means; focus driving means for determining focusing based on a sampling result of the AF evaluation value of the sampling means, and driving the focus lens system to a focus position; A full-range sampling focus system movement setting unit that always executes sampling of the AF evaluation value regardless of the sampling result of the AF evaluation value; and sampling of the AF evaluation value when focusing is determined based on the sampling result of the AF evaluation value. Macro sampling sampling lens system movement setting means for canceling, and movement amount changing means for changing the entire width of the movement amount of the focus lens system for full range sampling of the whole area sampling focus lens system movement setting means according to the position of the zoom lens system. And characterized by having Over autofocus system.