JP3820076B2 - Automatic focusing device, digital camera, portable information input device, focusing position detection method, and computer-readable recording medium - Google Patents

Automatic focusing device, digital camera, portable information input device, focusing position detection method, and computer-readable recording medium Download PDF

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Publication number
JP3820076B2
JP3820076B2 JP2000058838A JP2000058838A JP3820076B2 JP 3820076 B2 JP3820076 B2 JP 3820076B2 JP 2000058838 A JP2000058838 A JP 2000058838A JP 2000058838 A JP2000058838 A JP 2000058838A JP 3820076 B2 JP3820076 B2 JP 3820076B2
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Prior art keywords
focus
lens
detecting
subject
focusing
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JP2001249267A (en
Inventor
茂 入沢
達敏 北島
彰宏 吉田
憲昭 尾島
純一 篠原
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株式会社リコー
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic focusing device, a digital camera, a portable information input device, a focusing position detection method, and a computer-readable recording medium. Specifically, the detection of the focusing position is performed using an external AF and a CCD-AF. The present invention relates to an automatic focusing device, a digital camera, a portable information input device, a focusing position detection method, and a computer-readable recording medium.
[0002]
[Prior art]
As an AF method of a conventional electronic still camera, a CCD, a CCD-AF method in which a focus peak is detected by a luminance signal accumulated in the CCD while driving a focus lens in the optical axis direction, or a triangulation method is used. An automatic focusing mechanism is used alone.
[0003]
[Problems to be solved by the invention]
However, as shown in FIG. 17, the CCD-AF system is a system in which the CCD or focus lens is driven from infinity to the nearest position to find the focus peak, and therefore it takes time to detect the in-focus position. There is a problem that it takes. In order to solve the above-described problem, as shown in FIG. 18A, rough sampling is performed from infinity to the nearest position to detect the approximate focus position, and then, as shown in FIG. 18B. A method of detecting the final in-focus position by performing fine sampling near the approximate in-focus position has also been proposed. According to such a method, the detection time of the in-focus position can be slightly shortened, but it cannot be said to be sufficient.
[0004]
  Also,UpIn the triangulation method described above, a parallax shift in distance measurement on the close distance side is likely to occur. There are problems such as poor performance on the telephoto side. Recently, digital cameras equipped with a zoom lens have also become widespread. In general, the accuracy of AF differs depending on the focal length.
[0005]
The present invention has been made in view of the above, and in an automatic focusing apparatus and a focusing position detection method including a zoom lens system, an automatic focusing that can detect an accurate focusing position in a short time is provided. It is an object to provide a focusing device and a focusing position detection method.
[0006]
[Means for Solving the Problems]
  In order to solve the above-described problem, the invention according to claim 1 is directed to a lens system including a focus lens system and a zoom lens that forms a subject image at a predetermined position, and a subject image input via the lens system. Imaging means for imaging and outputting image data; and first focus position detection means for detecting the focus position by moving the lens system and sampling the contrast of the subject using the image pickup means; A second focus position detecting means for detecting a focus position of the lens system by detecting a distance from a subject using a photoelectric conversion means different from the imaging means; and the first focus position. A focus position determining means for determining a final focus position based on the focus position detected by the detection means and the second focus position detecting means, and the focus position determining means comprises:, The first focus position detecting meansSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance from the subject detected by the second focus position detecting meansAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,When the lens system is wide, the lens system is set to be narrow, and the lens system is set to be wide as it becomes telephoto.
[0007]
  According to the above invention, the lens system including the focus lens system and the zoom lens system and the subject image are formed at predetermined positions, and the imaging unit captures the subject image input through the lens system and outputs the image data. The first focus position detection means uses the image pickup means to detect the focus position by moving the lens system and sample the contrast of the subject, and the second focus position detection means is the image pickup means. Uses different photoelectric conversion means to detect the distance to the subject to detect the focus position of the lens system, and the focus position determination means detects the first focus position detection means and the second focus position detection. The final focus position is determined based on the focus position detected by the means,Of the first in-focus position detecting meansSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance from the subject detected by the second focus position detecting meansAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,When the lens system is wide, the lens system is set narrower, and the lens system is set wider toward the telephoto side.
[0008]
  The invention according to claim 2 is the invention according to claim 1,Further, the size of the area in the light receiving screen of the image pickup means for detecting the contrast of the subject is set larger when the lens system is wide, and smaller as the distance becomes tele.
[0009]
  Further, the invention according to claim 3 is the claim.1In the invention according toFurthermore, the sampling interval for detecting the contrast of the subject is set to be large when the lens system is wide, and is set to be small as the distance becomes tele..
[0015]
  Claims4The invention according to claim 1 to claim 13In the invention according to any one of the above, the in-focus position determination means is based on the focal length of the lens system, and the in-focus result of the first in-focus position detection means or the second in-focus position detection means Is determined as the final in-focus position. According to the above invention, the focus position determination means determines the focus result of the first focus position detection means or the second focus position detection means as the final focus position based on the focal length of the lens system. decide.
[0016]
  Claims5The invention according to claim4In the invention according to the first aspect, the focus position determination unit is configured to detect the focus position detected by the first focus position detection unit and the second focus position detection unit when the lens system is wide. Of these, the one with the shorter subject distance corresponding to the in-focus position is determined as the final in-focus position. According to the above invention, when the lens system is wide, the in-focus position determining means includes the in-focus position detected by the first in-focus position detecting means and the second in-focus position detecting means. The one closer to the subject corresponding to the focus position is determined as the final focus position.
[0017]
  Claims6The invention according to claim4In the invention according to this aspect, the in-focus position determining means determines the in-focus position detected by the first in-focus position detecting means as the final in-focus position when the lens system is tele. is there. According to the above invention, when the lens system is tele, the focus position determining means determines the focus position detected by the first focus position detecting means as the final focus position.
[0019]
  Claims7The invention according to any one of claims 1 to 6 is the invention according to any one of claims 1 to 6, wherein the second operation is performed at predetermined time intervals prior to the operation of the focusing operation member for instructing the operation of the focusing operation. The in-focus position detecting means executes a distance measuring process for measuring the distance to the subject, and when the in-focus operation member is operated, the first in-focus position detecting means The operation of detecting the in-focus position is executed with the in-focus position detected by the in-focus position detecting means as the reference position. According to the above invention, prior to the operation of the focusing operation operating member for instructing the operation of the focusing operation, the second focusing position detection means measures the distance to the subject at a predetermined time interval. When the focusing process operation member is operated after performing the distance measuring process, the first focus position detecting means is detected by the second focus position detecting means.The range before and after the sampling position corresponding to the distance to the subject is the sampling rangeAn operation for detecting the in-focus position is executed.
[0020]
  Claims8The invention according to claim 1 to claim 17The invention according to any one of the above is applied. According to the invention, claims 1 to claim7The automatic focusing device according to any one of the above was applied to a digital camera.
[0021]
  Claims9The invention according to claim 1 to claim 17The invention according to any one of the above is applied. According to the invention, claims 1 to claim7The automatic focusing device according to any one of the above was applied to a portable information input device.
[0022]
  Claims10According to the invention, in a focus position detection method for detecting a focus position with respect to a subject of a lens system including a focus lens system and a zoom lens system, the distance from the subject is determined by using a photoelectric conversion unit different from the imaging unit. A first step of detecting and detecting the in-focus position of the lens system; and a second step of detecting the in-focus position by sampling the contrast of the subject by moving the lens system using the imaging means. And a third step of determining a final in-focus position based on the in-focus position detected in the first step and the second step, and the third step IsAccording to the second stepSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance from the subject detected in the first stepAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,When the lens system is wide, the lens system is set narrower, and the lens system is set wider as it becomes telephoto.
[0023]
  According to the above invention, in the first step, the photoelectric conversion means different from the imaging means is used to detect the distance to the subject to detect the focus position of the lens system, and in the second step, the imaging is performed. The focus position is detected by moving the lens system using the means and sampling the contrast of the subject to detect the focus position. In the third step, the focus position detected in the first step and the second step is detected. To determine the final focus position,By the second stepSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance from the subject detected in the first stepAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,If the lens system is wide, the lens system is set narrower, and the lens system is set wider as it becomes telephoto.
[0024]
  Claims11The invention according to claim10In the invention according to the present invention, the size of the area in the light receiving screen of the imaging means for detecting the contrast of the subject is set larger when the lens system is wide, and smaller as it becomes tele.
[0025]
  Claims12The invention according to claim10In the invention according to the present invention, the sampling interval for detecting the contrast of the subject is set larger when the lens system is wide, and smaller as the distance becomes tele.
[0026]
  Claims13The invention according to claim 11 is a claim.12In the in-focus position detection method according to any one of the above, in the third step, the focus detected in the first step or the second step is based on the focal length of the lens system. The focus result is determined as a final focus position.
[0032]
  Claims14The invention according to claim13In the invention according to the third aspect, in the third step, when the lens system is wide, among the in-focus positions detected in the first step and the second step, it corresponds to the in-focus position. The one with the shorter object distance is determined as the final focus position. According to the above invention, in the third step, when the lens system is wide, the subject distance corresponding to the in-focus position among the in-focus positions detected in the first step and the second step is The closest one is determined as the final focus position.
[0033]
  Claims15The invention according to claim13In the present invention, in the third step, when the lens system is tele, the focus position detected in the second step is determined as the final focus position. According to the above invention, in the third step, when the lens system is tele, the focus position detected in the second step is determined as the final focus position.
[0035]
  Claims16According to the invention, in a focus position detection method for detecting a focus position with respect to a subject of a lens system including a focus lens system, a predetermined operation is performed prior to an operation of a focus operation member for instructing a focus operation. A first step of detecting a distance to the subject using a photoelectric conversion unit different from the imaging unit at time intervals, and a measurement of the first step when the focusing operation member is operated. While calculating the reference position using the distance result,CoveredSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance from the subject detected in the first stepAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,When the lens system is wide, the second step is set to be narrow, and the lens system is set to be wider as it becomes tele; and the imaging means is used in the vicinity of the reference position calculated in the second step. A third step of detecting the in-focus position within the set sampling range by moving the lens system; and the in-focus position of the lens system by detecting the distance to the subject using the photoelectric conversion means And a fifth step of determining a final focus position based on the focus positions detected in the third step and the fourth step, and The third step and the fourth step are performed substantially simultaneously.
[0036]
  According to the above invention, in the first step, prior to the operation of the focusing operation member for instructing the focusing operation, the photoelectric conversion unit different from the imaging unit is used at a predetermined time interval, The distance to the subject is detected, and in the second step, when the focusing operation member is operated, the reference position is calculated using the distance measurement result of the first step, andDepending on the focal length of the lens system, the sampling range for detecting the contrast of the subject is narrower than the entire region and is a range before and after the sampling position corresponding to the distance to the subject detected by the first step. , If the lens system is wide, set it narrower, set it wider as it becomes tele,In the third step, the in-focus position is detected in the sampling range set by moving the lens system in the vicinity of the reference position calculated in the second step using the imaging means, and the fourth step In the step, the photoelectric conversion means is used to detect the distance to the subject to detect the focus position of the lens system, and in the fifth step, the focus detected in the third step and the fourth step. Based on the position, the final in-focus position is determined, and the third step and the fourth step are executed substantially simultaneously.
[0037]
  Claims17The invention according to claim 11 is a claim.16The program for making a computer perform each process of invention described in any one of these is recorded. According to the above invention, by executing a program recorded on a recording medium by a computer, claims 11 to 11 are provided.16Each process of the invention described in any one of is realized.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of an automatic focusing device, a digital camera, a portable information input device, a focusing position detection method, and a computer-readable recording medium according to the present invention will be described below in detail with reference to the accompanying drawings. To do.
[0039]
FIG. 1 is a block diagram of a digital camera to which an automatic focusing device and a focus position detection method according to the present invention are applied. In the figure, 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, a CDS circuit 104, a variable gain amplifier (AGC amplifier) 105, an A / A D converter 106, IPP 107, DCT 108, coder 109, MCC 110, DRAM 111, PC card interface 112, CPU 121, display unit 122, operation unit 123, SG (control signal generation) unit 126, strobe device 127, battery 128, DC-DC A converter 129, an EEPROM 130, a focus driver 131, a pulse motor 132, a zoom driver 133, a pulse motor 134, a motor driver 135, and an external AF sensor 136 are provided. A detachable PC card 150 is connected via the PC card interface 112.
[0040]
The lens unit includes a mechanical mechanism 102 including a lens 101 system, an aperture / filter unit, and the like. A mechanical shutter of the mechanical mechanism 102 performs simultaneous exposure of two fields. The lens system 101 is composed of, for example, a varifocal lens, and includes a focus lens system 101a and a zoom lens system 101b.
[0041]
The focus driver 131 drives the pulse motor 132 according to the control signal supplied from the CPU 121 to move the focus lens system 101a in the optical axis direction. The zoom driver 133 drives the pulse motor 134 according to the control signal supplied from the CPU 121 to move the zoom lens system 101b in the optical axis direction. Further, the motor driver 135 drives the mechanical mechanism 102 in accordance with a control signal supplied from the CPU 121, and sets, for example, an aperture value of the aperture.
[0042]
FIG. 2 is a diagram illustrating an example of the relationship between the number of pulses Zp of the pulse motor 134 (motor equally divided into 18) and the lens extension amount (mm) of the zoom lens system 101b. FIG. 3 is a diagram showing an example of the relationship between the shooting distance (1 / L) and the lens extension amount (mm) of the zoom lens system 101b when the zoom position is Wide to Tele.
[0043]
A CCD (charge coupled device) 103 converts an image input via the lens unit into an electrical signal (analog image data). A CDS (correlated double sampling) circuit 104 is a circuit for reducing noise in the CCD type image pickup device.
[0044]
In addition, the AGC amplifier 105 corrects the level of the signal that has been correlated and sampled by the CDS circuit 104. The gain of the AGC amplifier 105 is set by the CPU 121 when setting data (control voltage) is set in the AGC amplifier 105 via a D / A converter built in the CPU 121. Further, the A / D converter 106 converts analog image data from the CCD 103 input via the AGC amplifier 105 into digital image data. That is, the output signal of the CCD 103 is converted into a digital signal through the CDS circuit 104 and the AGC amplifier 105 and by the A / D converter 106 at an optimum sampling frequency (for example, an integer multiple of the subcarrier frequency of the NTSC signal). Is done.
[0045]
Further, an IPP (Image Pre-Processor) 107, a DCT (Discrete Cosine Transform) 108, and a coder (Huffman Encoder / Decoder) 109, which are digital signal processing units, are provided for digital image data input from the A / D converter 106. Various processing, correction, and data processing for image compression / decompression are performed separately for color differences (Cb, Cr) and luminance (Y). The DCT 108 and the coder 109 perform, for example, orthogonal transformation / inverse orthogonal transformation, which is a JPEG-compliant image compression / decompression process, and Huffman coding / decoding, which is a JPEG-compliant image compression / decompression process.
[0046]
Further, an MCC (Memory Card Controller) 110 temporarily stores the compressed image and records it on the PC card 150 or reads it from the PC card 150 via the PC card interface 112.
[0047]
The CPU 121 uses the RAM as a work area according to a program stored in the ROM, and controls all operations inside the digital camera according to an instruction from the operation unit 123 or an external operation instruction such as a remote controller (not shown). Specifically, the CPU 121 controls an imaging operation, an automatic exposure (AE) operation, an automatic white balance (AWB) adjustment operation, an AF operation, and the like.
[0048]
Camera power is input from a battery 128, such as NiCd, nickel metal hydride, or a lithium battery, to the DC-DC converter 129 and supplied into the digital camera.
[0049]
The display unit 122 is realized by an LCD, LED, EL, or the like, and displays captured digital image data, decompressed recorded image data, and the like. The operation unit 123 externally performs a release key for giving a shooting instruction, a zoom key for setting a zoom position (Tele (Tele) to Wide (Wide)) of the zoom lens system 101b, function selection, and other various settings. It has buttons and so on. The CPU 121 executes an AF operation or the like when the release key is pressed halfway and RL-1 is turned on, and performs a shooting operation when the release key is fully pressed and RL-2 is turned on. In the EEPROM 130, adjustment data and the like used when the CPU 121 controls the operation of the digital camera are written.
[0050]
The above-described digital camera 100 (CPU 121) includes a recording mode in which image data obtained by imaging a subject is recorded on the PC card 150, a display mode in which image data recorded on the PC card 150 is displayed, and captured image data. Is provided directly on the display unit 122.
[0051]
FIG. 4 is a diagram illustrating an example of a specific configuration of the IPP 107. As shown in FIG. 4, the IPP 107 includes a color separation unit 1071 that separates digital image data input from the A / D converter 106 into R, G, and B color components, and separated R, G, and B images. A signal interpolation unit 1072 that interpolates data, a pedestal adjustment unit 1073 that adjusts the black level of each of the R, G, and B image data, and a white balance adjustment unit 1074 that adjusts the white level of each of the R and B image data , A digital gain adjustment unit 1075 that corrects R, G, and B image data with a gain set by the CPU 121, a gamma conversion unit 1076 that performs γ conversion of the R, G, and B image data, and an RGB image A matrix unit 1077 for separating data into color difference signals (Cb, Cr) and luminance signals (Y), and a video signal based on the color difference signals (Cb, Cr) and luminance signals (Y). A video signal processing unit 1078 to be output to the display unit 122, and a.
[0052]
Further, the IPP 107 passes through only a Y calculating unit 1079 that detects luminance data (Y) of image data after pedestal adjustment by the pedestal adjusting unit 1073, and a predetermined frequency component of the luminance data (Y) detected by the Y calculating unit 1079. The BPF 1080 to be output, the AF evaluation value circuit 1081 that outputs the integrated value of the luminance data (Y) that has passed through the BPF 1080 to the CPU 121 as an AF evaluation value, and the digital count value corresponding to the luminance data (Y) detected by the Y calculation unit 1079 AE evaluation value circuit 1082 that outputs to the CPU 121 as an AE evaluation value, a Y calculation unit 1083 that detects luminance data (Y) of each of the R, G, and B image data after adjustment by the white balance adjustment unit 1074, and Y The luminance data (Y) of each color detected by the calculation unit 1083 is counted, and the AWB of each color is counted. And AWB evaluation value circuit 1084 outputs the CPU 121 as a value, and a CPUI / F1085 is an interface with the CPU 121, and the DCTI / F1086 such an interface with the DCT108.
[0053]
The external AF sensor 136 in FIG. 1 is composed of a passive distance measuring sensor, and is used to measure the distance of the subject. FIG. 5 is a diagram showing a schematic configuration of the external AF sensor. The external AF sensor 136 includes a lens 151, photosensor arrays 152a (left side) and 152b (right side), and an arithmetic circuit (not shown). The principle of distance measurement of the external AF sensor 136 will be described with reference to FIGS. In FIG. 5, the distance to the subject is d, the distance between the lens 151 and the photo sensor array 152a (left side), 152b (right side) is f, and the width of the light input to the photo sensor array 152a is X1, X2, and light, respectively. The distance d from the front surface of the external AF sensor 136 to the subject can be calculated by d = B · f / (X1 + X2) by triangulation. FIG. 6 shows the subject images of the left and right photosensor arrays, and the arithmetic circuit integrates the light amounts of the subject images of the respective photosensor arrays and calculates the deviation of the left and right sensor data, thereby calculating the subject distance d. Calculate and output to the CPU 121.
[0054]
In this specification, the operation of detecting the in-focus position using the external AF sensor 136 is referred to as external AF, and the case of detecting the in-focus position using the CCD 103 is referred to as CCD-AF (internal AF). In the CCD-AF, the focus lens 101a is moved, the AF evaluation value indicating the contrast of the subject corresponding to the image signal output from the CCD 103 is sampled, and the hill-climbing servo system using the peak position of the AF evaluation value as the in-focus position. Is used. Performing AF using external AF and CCD-AF is called hybrid AF.
[0055]
Next, an operation example (operation example 1 and operation example 2) related to AF of the digital camera having the above configuration will be described. The operation example 1 shows an operation example when the CCD-AF and the external AF are executed substantially simultaneously, and the operation example 2 shows an operation example when the external AF is executed prior to the CCD-AF.
(Operation example 1)
An operation example 1 relating to AF of a digital camera will be described with reference to FIGS. FIG. 7 is a flowchart for explaining an operation example 1 regarding the AF of the digital camera executed under the control of the CPU 121.
[0056]
In FIG. 7, first, the CPU 121 determines whether or not the release key is pressed halfway and RL-1 is turned on (step S1). When the release key is pressed halfway and RL-1 is turned on, the CPU 121 determines the zoom position of the zoom lens system 101b (step S2) and sets the zoom position (focal length) of the zoom lens system 101b. Accordingly, the CCD-AF sampling conditions are set (step S3). The CPU 121 determines the zoom position by the number of drive pulses of the pulse motor 134 that drives the zoom lens system 101b.
[0057]
Here, the sampling conditions of the CCD-AF are as follows: (1) AF evaluation value sampling range when CCD-AF is executed (movement range of the focus lens system 101a), and (2) AF evaluation value by CCD-AF. There are the AF area range of the light receiving surface of the CCD 103 when sampling is performed, and (3) the sampling interval of the AF evaluation value with respect to the moving amount of the focus lens 101a when performing CCD-AF. The CPU 121 sets one or a plurality of sampling conditions (1) to (3) according to the zoom position (focal length) of the zoom lens system 01b.
[0058]
(1) AF evaluation value sampling range when CCD-AF is executed (movement range of the focus lens system 101a)
FIG. 8 is an explanatory diagram for explaining a sampling range (movement range of the focus lens system 101a) when executing CCD-AF. In the figure, the horizontal axis indicates the lens position (nearest to infinity), the vertical axis indicates the contrast of the subject (AF evaluation value), and a in the figure indicates the sampling range. By setting an appropriate CCD-AF sampling range (sampling width) according to the focal length, it is possible to achieve both the accuracy and speed of in-focus position detection. The CPU 121 sets the sampling range of the CCD-AF to be narrow and increases the speed of the CCD-AF when the required range of accuracy is wide enough for the external AF accuracy. On the other hand, the CPU 121 sets a wide sampling width of the CCD-AF in the case of tele that has insufficient capability with the accuracy of the external AF.
[0059]
(2) AF area range of the light receiving surface of the CCD 103 when the AF evaluation value is sampled by the CCD-AF
FIG. 9 is a diagram for explaining the AF area of the light receiving surface of the CCD 103. This figure shows the inside of the light receiving surface of the CCD 103, and the CPU 121 sets an AF area for acquiring an AF evaluation value within this light receiving surface. This figure shows a case in which the light receiving surface of the CCD 103 is divided into 15 horizontal parts and 10 vertical parts. The CPU 121 can set an AF area of any size within the light receiving surface of the CCD 103. By setting an appropriate AF area of the CCD-AF according to the focal length, it is possible to achieve both the accuracy and speed of in-focus position detection. The CPU 121 sets the entire screen as an AF area and samples the AF evaluation value for the entire screen when the subject area on the screen is considered to be wide, as shown in FIG. The AF evaluation value is sampled at a slow sampling period. On the other hand, in the case of a tele that seems to have a large area occupied by the subject on the screen, the CPU 121 sets only the center portion of the screen as the AF area as shown in FIG. Only the AF evaluation value is sampled, and the AF evaluation value is sampled at an early sampling period. In addition, since the sampling period of the CCD-AF is determined by the image processing time, if the range of the image to be processed is narrowed, sampling can be performed at a faster period accordingly.
[0060]
(3) Sampling interval of the AF evaluation value with respect to the moving amount of the focus lens system 101a when executing CCD-AF
FIG. 10 is an explanatory diagram for explaining the sampling interval of the AF evaluation value with respect to the movement amount of the focus lens system 101a of the CCD-AF. In the figure, the horizontal axis indicates the lens position (nearest to infinity), the vertical axis indicates the contrast of the subject (AF evaluation value), and b in the figure indicates the sampling interval of the AF evaluation value. By setting an appropriate CCD-AF sampling interval according to the focal length, it is possible to achieve both the accuracy and speed of in-focus position detection. For example, at a focal length with a deep focal depth, the CPU 121 increases the lens movement interval to increase the AF evaluation value sampling interval, and reduces the number of sampling points to increase the speed of the CCD-AF.
[0061]
Then, the CPU 121 sets the focus lens system 101a to the CCD-AF start position (reference position) (step S4). As the start position (reference position) of the CCD-AF, for example, the current position of the lens system can be used. This is because it is usually considered that the frequency of continuous shooting under the same conditions is high.
[0062]
Then, the CPU 121 starts the external AF and the CCD-AF simultaneously (step S5). In the external AF, the external AF sensor 136 performs distance measurement processing, measures the distance to the subject, and detects the in-focus position. In the CCD-AF, the focus lens system 101a is moved in the vicinity of the reference position, the AF evaluation value is acquired under the set sampling condition, and the focus position is detected.
[0063]
Then, the CPU 121 determines whether or not the external AF has ended (step S6). If the external AF has ended, the distance measurement result of the external AF corresponds to the start position (reference position) of the CCD-AF. It is determined whether or not the photographing distance to be different is a predetermined value or more (step S7). When the distance measurement result of the external AF differs from the shooting distance corresponding to the start position (reference position) of the CCD-AF by a predetermined value or more, the CPU 121 interrupts the CCD-AF and is measured by the external AF sensor 136. The focus lens system 101b is moved to a position corresponding to the distance (focus position) (step S8). Thereafter, CCD-AF is re-executed near the position (step S9).
[0064]
In step S10, the CPU 121 determines whether or not the CCD-AF has ended. If the CCD-AF has ended, the CPU 121 determines the focus position of the external AF and the CCD-AF based on the zoom position (focal length). Is determined as the final in-focus position (step S11).
[0065]
Here, a specific method for determining one of the focus position of the external AF and the focus position of the CCD-AF as the final focus position based on the zoom position will be described. CCD-AF generally has higher accuracy, but in the case of Wide, sufficient accuracy can be secured even as a result of external AF. Therefore, it is not necessary to prioritize CCD-AF for Wide. In the present embodiment, in the case of Wide, the one with the shorter subject distance corresponding to the in-focus position is determined as the final in-focus position, while in the case of Tele, the in-focus position of the CCD-AF is determined. Determine the final focus position. Note that, with reference to a point that can be in focus with the accuracy of external AF between Wide and Tele, this point is preferentially selected as “closer” on the wide side and CCD-AF on the Tele side. The above is processing when both the distance measurement results are reliable, and when the reliability of the results is low, the final focus position is determined in consideration of the information on the reliability of both. Is preferred.
[0066]
In FIG. 7, the CPU 121 moves the focus lens system 101a to the determined focus position (step S12). Thereafter, when the release key is fully pressed and RL-2 is turned on, a shooting operation is performed, and image data of the subject is captured and recorded in the PC card 150.
[0067]
FIG. 11 is a timing chart for explaining the execution timing of the external AF and the CCD-AF in the first operation example. (A) of the figure shows the timing when the distance measurement result of the external AF and the photographing distance corresponding to the start position (reference position) of the CCD-AF are different from each other by a predetermined value or more. In FIG. 6B, the distance measurement result of the external AF and the shooting distance corresponding to the start position (reference position) of the CCD-AF are different from each other by a predetermined value, and the CCD-AF is interrupted and measured by the external AF sensor 136. The case where the position corresponding to the determined distance is set as a new reference position and CCD-AF is executed again ((2)) is shown.
[0068]
(Operation example 2)
An operation example 2 relating to AF of the digital camera will be described with reference to FIGS. FIG. 12 is a flowchart for explaining an operation example 2 related to AF of the digital camera executed under the control of the CPU 121.
[0069]
In FIG. 12, first, when the power is turned on (step S21), the CPU 121 determines whether it is the external AF execution timing (step S22). As a result of the determination, if it is not the execution timing of the external AF, the process proceeds to step S24. On the other hand, when it is the execution timing of the external AF, the CPU 121 executes a distance measurement process using the external AF (step S23), and the external AF sensor 136 measures the distance to the subject and proceeds to step S24. To do.
[0070]
In step S24, the CPU 121 determines whether or not the release key is pressed halfway and RL-1 is turned on. If RL-1 is not ON, the process returns to step S22, and external AF distance measurement processing is performed at the external AF execution timing until RL-1 is turned ON. On the other hand, when RL-1 is turned on in step S24, the CPU 121 determines the zoom position of the zoom lens system 101b (step S25), and according to the zoom position (focal length) of the zoom lens system 101b. CCD-AF sampling conditions are set (step S26). The CPU 121 determines the zoom position by the number of drive pulses of the pulse motor 134 that drives the zoom lens system 101b. Since the sampling conditions of the CCD-AF are the same as those in the first embodiment, the description thereof is omitted.
[0071]
In step S27, the CPU 121 calculates the start position (reference position) of the CCD-AF based on the distance measurement result of the external AF. Here, a method for calculating the start position (reference position) of the CCD-AF based on the distance measurement result of the external AF will be described. For example, a method of predicting the reference position from the distance measurement results of the past two points of the external AF can be used. This makes it possible to determine whether the subject is approaching, moving away, or stopped.
[0072]
FIG. 13 is an explanatory diagram for explaining a case where the start position (reference position) of the CCD-AF is calculated from the distance measurement results of the last two points of the external AF. In this figure, Lccd is the predicted subject distance (CCD-AF reference position), L2 is the subject distance by the external AF immediately before the release operation, L1 is the subject distance by the external AF one time before L2, and t1 is the continuity. The interval between the numeric external AF and t2 indicates the time from the external AF to the release immediately before the release operation. The predicted subject distance (CCD-AF reference position) Lccd is calculated by the following equation. Then, the lens system position corresponding to the calculated predicted subject distance Lccd is determined as the start position (reference position) of the CCD-AF.
[0073]
Lccd = L2 + t2 × (L2-L1) / t1
For example, when t1 = t2, if the past two times are 2 m and 3 m, the next is predicted to be 4 m, while if the past two times is 4 m and 3 m, the next is predicted to be 2 m. Therefore, CCD-AF is performed at the position of the lens system corresponding to around 4 m and around 2 m, respectively.
[0074]
Here, the reference position of the CCD-AF is determined from the past two points, but time series data of the past three points or more may be used. Thereby, a finer moving object prediction becomes possible. For example, when determining the CCD-AF reference position from the past three points, it is possible to determine whether the subject is approaching, moving away, stopped, or swinging back and forth. For example, by comparing the first, second, second, and third subject distances, the acceleration component of the subject movement can also be detected. In this case, a method of approximating with a quadratic curve (such as a subject falling from above), a method of approximating with a trigonometric function (such as a subject on a swing), or the like can be used.
[0075]
Then, the CPU 121 moves the focus lens system 101a to the calculated CCD-AF start position (reference position) (step S28). After moving the focus lens system 101a to the reference position, external AF and CCD-AF are started simultaneously (step S29). In the external AF, the external AF sensor 136 measures the distance to the subject and detects the focus position. In the CCD-AF, the focus lens system 101a is moved in the vicinity of the reference position, the AF evaluation value is acquired under the set sampling condition, and the focus position is detected.
[0076]
Subsequently, the CPU 121 determines whether or not the external AF and the CCD-AF are finished (step S30). When the external AF and the CCD-AF are finished, the CPU 121 determines whether the external AF and the CCD-AF are finished based on the zoom position (focal length). Either the in-focus position detected by AF or the in-focus position detected by CCD-AF is determined as the final in-focus position (step S31). The method for determining either the in-focus position of the external AF or the in-focus position of the CCD-AF as the final in-focus position based on the zoom position (focal length) is the same as in the first operation example, and the description thereof is omitted. To do.
[0077]
Then, the CPU 121 moves the focus lens system 101a to the determined focus position (step S32). Thereafter, when the release key is fully pressed and RL-2 is turned on, a photographing operation is performed, and the image data of the subject is captured and recorded in the PC card 150.
[0078]
With reference to FIG. 14, the execution timing of the external AF and the CCD-AF in the operation example 2 will be described. FIG. 14 is a timing chart for explaining execution timings of the external AF and the CCD-AF in the second operation example. (A) in the figure is when the release is pressed at the execution timing of the external AF, (b) is when the release is pressed during the pause of the external AF, and (c) is the release during the external AF operation. When (1) is pressed, (d) shows the timing when the release is pressed during external AF operation (2).
[0079]
As shown in FIG. 6A, when the release is pressed at the external AF execution timing, the external AF and the CCD-AF are executed at the release ON timing. Also, as shown in FIG. 5B, when the release is pressed while the external AF is stopped, the external AF is stopped and the external AF and CCD-AF are executed at the release ON timing. . Further, when the release is pressed during the external AF operation, the timing shown in FIG. 10C and the timing shown in FIG. 10D are considered, and any timing may be used.
[0080]
When the release is pressed during the external AF operation, the external AF (3) may be stopped at the time of release and re-driven as shown in FIG. In this case, the data of the external AF (3) is not acquired, and the final focus position is determined based on the data of the external AF (4) and the result of the CCD-AF.
[0081]
If the release button is pressed during the external AF operation, as shown in FIG. 4D, the external AF (3) is not interrupted even at the time of release, and the external AF (3) data and the CCD- The final in-focus position is determined based on the result of AF. Usually, since the external AF operation time is 0.1 second or less, there is no problem in practical use even in the method (d). However, when the subject is at low brightness, the external AF takes about 0.1 seconds, so the method (c) is more reliable.
[0082]
In step S28, if the distance measurement result detected by the external AF and the shooting distance corresponding to the in-focus position detected by the CCD-AF differ by a predetermined value or more, as shown in FIG. The CCD-AF may be performed again by changing the start position (reference position) of the CCD-AF.
[0083]
FIG. 16 is an explanatory diagram for explaining the second operation example. In the figure, the vertical axis represents the contrast (AF evaluation value), and the horizontal axis represents the lens position (nearest to infinite). First, the in-focus position is detected by external AF, and then sampling is performed by CCD-AF in the vicinity of the detected in-focus position to detect the in-focus position. Then, the final focusing position is determined based on both focusing positions.
[0084]
As described above, according to the present embodiment, the zoom lens system is provided, the external AF uses the external AF sensor 136 to detect the focus position, and the CCD-AF moves the focus lens 101a. The AF evaluation value indicating the contrast of the subject according to the image signal output from the CCD 103 is sampled, the peak position of the AF evaluation value is detected as the in-focus position, and the in-focus position detected by the CCD-AF and the external AF In the digital camera that determines the final in-focus position based on the above, the sampling condition for sampling the AF evaluation value with the CCD-AF is set according to the focal length of the lens system (zoom lens system) Therefore, it is possible to set an appropriate CCD-AF sampling condition according to the focus position, and to a system equipped with a zoom lens system. It can have, it is possible to highly accurate and high-speed focus position detection.
[0085]
In the present embodiment, since the sampling range for sampling the AF evaluation value is changed as the CCD-AF sampling condition, the sampling for sampling an appropriate AF evaluation value according to the focal length is performed. The range can be set, and it is possible to achieve both the accuracy and speed of in-focus position detection.
[0086]
In the present embodiment, as the CCD-AF sampling condition, the size (sampling period) of the AF area of the light receiving screen of the CCD 103 for sampling the AF evaluation value is changed. It is possible to achieve both detection accuracy and speed.
[0087]
In the present embodiment, the sampling interval for sampling the AF evaluation value is changed as the CCD-AF sampling condition, so that it is possible to achieve both the accuracy and speed of in-focus position detection. Become.
[0088]
In the present embodiment, the final focus position is determined based on the detection result detected by the external AF or the CCD-AF based on the focal length of the lens system. The focus position can be detected.
[0089]
In addition, since the digital camera of the present embodiment uses a passive distance measuring sensor as the external AF sensor, it is possible to reduce the size, reduce the cost, and simplify the processing.
[0090]
Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified and executed without changing the gist of the invention. For example, in the present embodiment, an example in which the automatic focusing device and the automatic focusing method according to the present invention are applied to a digital camera has been described. It can also be applied to an input device or the like. In short, the present invention can be applied to all apparatuses that perform AF when inputting an image.
[0091]
【The invention's effect】
  As described above, according to the automatic focusing device of the first aspect, the lens system including the focus lens system and the zoom lens system and the subject image are formed at predetermined positions, and the imaging unit is connected via the lens system. The input subject image is picked up and image data is output. The first focus position detection means uses the image pickup means to move the lens system and sample the contrast of the subject to detect the focus position. The second focus position detection means uses a photoelectric conversion means different from the imaging means to detect the distance to the subject to detect the focus position of the lens system, and the focus position determination means is the first focus position determination means. Based on the in-focus position detected by the in-focus position detecting means and the second in-focus position detecting means, a final in-focus position is determined,Of the first in-focus position detecting meansSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance from the subject detected by the second focus position detecting meansAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,Since the lens system is set to be narrow when the lens system is wide and is set to be wide as the telephoto side is set, the sampling range of the first focus position detecting means can be set according to the focus position, and zooming can be performed. Even in a system including a lens system, it is possible to detect a focus position with high accuracy and high speed.
[0092]
  According to the automatic focusing device according to claim 2, in the automatic focusing device according to claim 1,Furthermore, the size of the area in the light receiving screen of the image pickup means for detecting the contrast of the subject is set to be large when the lens system is wide, and is set to be small as the distance becomes telephoto. In addition to the effect of the automatic focusing device according to item 1, it is possible to achieve both the accuracy and speed of focus position detection.
[0093]
  According to an automatic focusing device according to claim 3,1In the automatic focusing device according toFurther, since the sampling interval for detecting the contrast of the subject is set to be large when the lens system is wide and is set to be small as the distance becomes tele, the effect of the automatic focusing device according to claim 1 is achieved. In addition, it is possible to achieve both the accuracy and speed of focus position detection.
[0099]
  Claims4According to the automatic focusing device according to claim 1, claims 1 to3In the automatic focusing device according to any one of the above, the in-focus position determining unit is configured to display the in-focus result of the first in-focus position detecting unit or the second in-focus position detecting unit based on the focal length of the lens system. Since it is determined to be the final in-focus position, claims 1 to claim3In addition to the effect of the automatic focusing device according to any one of the above, it is possible to detect the focusing position with higher accuracy.
[0100]
  Claims5According to the automatic focusing device according to claim4In the automatic focusing device according to the present invention, the focusing position determination means includes a focusing position detected by the first focusing position detection means and the second focusing position detection means when the lens system is wide. In this case, it is determined that a subject having a shorter subject distance corresponding to the in-focus position is determined as the final in-focus position.4In addition to the effect of the automatic focusing device according to the above, even when the lens system is wide, it is possible to detect the focusing position with higher accuracy.
[0101]
  Claims6According to the automatic focusing device according to claim4In the automatic focusing apparatus according to the present invention, the focusing position determination means determines the focusing position detected by the first focusing position detection means as the final focusing position when the lens system is tele. The claims4In addition to the effect of the automatic focusing device according to the above, even when the lens system is tele, it is possible to detect the focusing position with higher accuracy.
[0103]
  Claims7According to the automatic focusing device according to claim 1, in the automatic focusing device according to any one of claims 1 to 6, prior to the operation of the focusing operation member for instructing the operation of the focusing operation, At a predetermined time interval, the second in-focus position detecting means executes a distance measuring process for measuring the distance from the subject. When the in-focus operation member is operated, the first in-focus position detecting means. Is the in-focus position detected by the second in-focus position detecting means.The range before and after the sampling position corresponding to the distance to the subject is the sampling rangeSince the operation of detecting the in-focus position is executed, in addition to the effect of the automatic in-focus device according to any one of claims 1 to 6, the in-focus position can be detected at a higher speed. It becomes.
[0104]
  Claims8According to the digital camera according to claim 1, claims 1 to7Since the automatic focusing device according to any one of the above is applied, it is possible to detect the in-focus position with high accuracy and high speed even in a digital camera including a zoom lens system.
[0105]
  Claims9According to the portable information input device according to claim 1, claims 1 to7Since the automatic focusing device according to any one of the above is applied, even in a portable information input device equipped with a zoom lens system, it is possible to detect a focusing position with high accuracy and high speed.
[0106]
  Claims10According to the in-focus position detection method, in the first step, the photoelectric conversion means different from the image pickup means is used to detect the distance to the subject to detect the in-focus position of the lens system. In this step, the imaging unit is used to move the lens system and the contrast of the subject is sampled to detect the in-focus position. In the third step, detection is performed in the first step and the second step. The final focus position is determined based on the focused position,By the second stepSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance to the subject detected in the first stepAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,Since the lens system is set to be narrow when the lens system is wide, and is set to be wide as the distance becomes tele, even in a system equipped with a zoom lens system, it is possible to detect the in-focus position with high accuracy and high speed.
[0107]
  Claims11According to the in-focus position detection method,10In the in-focus position detection method, the size of the area in the light receiving screen of the imaging means for detecting the contrast of the subject is set to be large when the lens system is wide, Since it is set to be small, in addition to the effect of the focus position detection method according to the eleventh aspect, it is possible to achieve both the accuracy and speed of focus position detection.
[0108]
  Claims12According to the in-focus position detection method,10In the in-focus position detection method according to the present invention, the sampling interval for detecting the contrast of the subject is set larger when the lens system is wide, and smaller as the distance becomes telephoto. Term10In addition to the effect of the in-focus position detection method, it is possible to achieve both the accuracy and speed of in-focus position detection.
[0114]
  Claims13According to the in-focus position detection method,10~ Claim12In the in-focus position detection method, in the third step, the in-focus result detected in the first step or the second step is determined as the final in-focus position based on the focal length of the lens system. So that the claims10~ Claim12In addition to the effect of the focus position detection method according to any one of the above, it is possible to detect the focus position with higher accuracy.
[0115]
  Claims14According to the in-focus position detection method,13In the in-focus position detection method, in the third step, when the lens system is wide, the in-focus position detected in the first step and the second step corresponds to the in-focus position. Since it is determined that the one with the shortest subject distance is the final focus position,13In addition to the effect of the in-focus position detecting method, it is possible to detect the in-focus position with higher accuracy even when the lens system is wide.
[0116]
  Claims15According to the in-focus position detection method,13In the in-focus position detection method according to claim 3, in the third step, when the lens system is tele, the in-focus position detected in the second step is determined as the final in-focus position. Term13In addition to the effect of the automatic focusing device according to the above, even when the lens system is tele, it is possible to detect the focusing position with higher accuracy.
[0118]
  Claims16According to the automatic focusing apparatus according to the first aspect, in the first step, prior to the operation of the focusing operation operation member for instructing the focusing operation, the photoelectric conversion unit different from the imaging unit is provided at a predetermined time interval. The distance to the subject is detected, and in the second step, when the focusing operation member is operated, the reference position is calculated using the distance measurement result in the first step, andCoveredSampling range for detecting the contrast of the subjectNarrower than the whole area, andThe distance to the subject detected in the first stepAs the range before and after the corresponding sampling position, depending on the focal length of the lens system,When the lens system is wide, the lens system is set to be narrow, and the lens system is set to be wide as it becomes tele. In the third process, the imaging system is used to adjust the lens system in the vicinity of the reference position calculated in the second process. The focus position is detected within the set sampling range by moving, and in the fourth step, the photoelectric conversion means is used to detect the distance to the subject and the focus position of the lens system is detected. In step 5, the final focus position is determined based on the focus positions detected in the third step and the fourth step, and the third step and the fourth step are executed substantially simultaneously. .
[0119]
  Claims17According to a computer readable recording medium according to claim10~ Claim16Since the program for making a computer perform each process of invention of any one of these is recorded, the system provided with the zoom lens system by executing the program currently recorded on the recording medium with a computer In this case, it is possible to detect the in-focus position with high accuracy and high speed.
[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 relationship between a pulse number Zp of a pulse motor (motor equally divided into 18 divisions) and a lens extension amount (mm) of a zoom lens system.
FIG. 3 is a diagram illustrating an example of a relationship between a shooting distance (1 / L) and a lens extension amount (mm) of a zoom lens system when the zoom position is Wide to Tele.
4 is a diagram illustrating an example of a specific configuration of the IPP in FIG. 1. FIG.
5 is a diagram showing a schematic configuration of the external AF sensor of FIG. 1. FIG.
FIG. 6 is an explanatory diagram for explaining a distance measuring principle of an external AF sensor.
FIG. 7 is a flowchart for explaining an operation example 1 regarding AF of the digital camera.
FIG. 8 is an explanatory diagram for explaining a sampling range when performing CCD-AF.
FIG. 9 is a diagram for explaining an AF area of a light receiving surface of a CCD.
FIG. 10 is an explanatory diagram for explaining a sampling interval of AF evaluation values with respect to a movement amount of a focus lens system of CCD-AF.
FIG. 11 is a timing chart for explaining execution timings of external AF and CCD-AF in an operation example 1;
FIG. 12 is a flowchart for explaining an operation example 2 regarding AF of the digital camera.
FIG. 13 is an explanatory diagram for explaining a case where a CCD-AF start position (reference position) is calculated from distance measurement results of the last two points of an external AF.
FIG. 14 is a timing chart for explaining execution timings of external AF and CCD-AF in an operation example 2;
FIG. 15 is a timing chart for explaining execution timings of external AF and CCD-AF in an operation example 2;
FIG. 16 is an explanatory diagram for explaining an operation example 2;
FIG. 17 is an explanatory diagram for explaining a conventional CCD-AF system.
FIG. 18 is an explanatory diagram for explaining a conventional CCD-AF system.
[Explanation of symbols]
100 digital camera
101 Lens system
101a Focus lens system
101b 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 section
123 Operation unit
125 motor driver
126 SG Department
127 Strobe
128 battery
129 DC-DC converter
130 EEPROM
131 Focus driver
132 Pulse motor
133 Zoom driver
134 Pulse motor
135 Motor driver
136 External AF sensor
150 PC card
151 lens
152 Photosensor Array
1071 Color separation unit
1072 Signal interpolation unit
1073 Pedestal adjustment unit
1074 White balance adjustment section
1075 Digital gain adjustment unit
1076 γ converter
1077 Matrix part
1078 Video signal processor
1079 Y operation part
1080 BPF
1081 AF evaluation value circuit
1082 AE evaluation value circuit
1083 Y operation part
1084 AWB evaluation value circuit
1085 CPU I / F
1086 DCTI / F
1075r, 1075g, 1075b multiplier

Claims (17)

  1. A lens system including a focus lens system and a zoom lens that forms a subject image at a predetermined position;
    Imaging means for imaging a subject image input via the lens system and outputting image data;
    A first in-focus position detecting unit that detects the in-focus position by sampling the contrast of the subject by moving the lens system using the imaging unit;
    Second focus position detection means for detecting a focus position of the lens system by detecting a distance to a subject using a photoelectric conversion means different from the imaging means;
    A focus position determination means for determining a final focus position based on the focus position detected by the first focus position detection means and the second focus position detection means;
    The in-focus position determining means has a sampling range for detecting the contrast of the object of the first in-focus position detecting means that is narrower than the entire area and the object detected by the second in-focus position detecting means. The range before and after the sampling position corresponding to the distance is set to be narrow when the lens system is wide, and wide as the telephoto side is set , according to the focal length of the lens system. Focusing device.
  2.   Further, the size of the area in the light receiving screen of the imaging means for detecting the contrast of the subject is set to be large when the lens system is wide, and is set to be small as the distance becomes tele. Item 2. The automatic focusing device according to Item 1.
  3.   2. The automatic focusing device according to claim 1, wherein the sampling interval for detecting the contrast of the subject is set to be large when the lens system is wide, and is set to be small as telephoto.
  4.   The in-focus position determining unit determines the in-focus position detected by the first in-focus position detecting unit or the second in-focus position detecting unit based on the focal length of the lens system as a final in-focus position. The automatic focusing device according to claim 1, wherein the automatic focusing device is determined.
  5.   When the lens system is wide, the in-focus position determining means is the in-focus position among the in-focus positions detected by the first in-focus position detecting means and the second in-focus position detecting means. The automatic focusing device according to claim 4, wherein the object focusing distance corresponding to the position is determined as the final focusing position.
  6.   The in-focus position determining means determines the in-focus position detected by the first in-focus position detecting means as a final in-focus position when the lens system is tele. 4. The automatic focusing device according to 4.
  7. Prior to the operation of the focusing operation operation member for instructing the operation of the focusing operation, the second focusing position detection means executes a ranging process for measuring the distance from the subject at a predetermined time interval. When the in-focus operation member is operated, the first in-focus position detecting means has a sampling position corresponding to the distance from the subject detected by the second in-focus position detecting means . The automatic focusing device according to any one of claims 1 to 6, wherein an operation of detecting a focusing position is performed using the front and rear ranges as sampling ranges .
  8. A digital camera to which the automatic focusing device according to any one of claims 1 to 7 is applied.
  9. A portable information input device to which the automatic focusing device according to any one of claims 1 to 7 is applied.
  10. In a focus position detection method for detecting a focus position with respect to a subject of a lens system including a focus lens system and a zoom lens system,
    A first step of detecting a focus position of the lens system by detecting a distance from a subject using a photoelectric conversion unit different from the imaging unit;
    A second step of detecting the in-focus position by sampling the contrast of the subject by moving the lens system using the imaging means;
    And a third step of determining a final in-focus position based on the in-focus position detected in the first step and the second step,
    In the third step, the sampling range when detecting the contrast of the subject in the second step is narrower than the entire region, and before and after the sampling position corresponding to the distance from the subject detected in the first step. The in-focus position detection method is characterized in that , depending on the focal length of the lens system, the range is set to be narrow when the lens system is wide and to be wide as telephoto.
  11. Further, the size of the area in the light receiving screen of the image pickup means for detecting the contrast of the subject is set to be large when the lens system is wide, and is set to be small as the distance becomes tele. Item 11. The focus position detection method according to Item 10 .
  12. 11. The in-focus position detection according to claim 10 , wherein the sampling interval for detecting the contrast of the subject is set to be large when the lens system is wide, and is set to be small as the distance is telephoto. Method.
  13. In the third step, the focus result detected in the first step or the second step is determined as a final focus position based on the focal length of the lens system. The in-focus position detection method according to any one of Items 11 to 12 .
  14. In the third step, when the lens system is wide, one of the in-focus positions detected in the first step and the second step that has a shorter subject distance corresponding to the in-focus position. 14. The focus position detection method according to claim 13 , wherein the final focus position is determined.
  15. 14. The focusing method according to claim 13 , wherein in the third step, when the lens system is a telephoto lens, the focusing position detected in the second step is determined as a final focusing position. Focus position detection method.
  16. In a focus position detection method for detecting a focus position with respect to a subject of a lens system including a focus lens system,
    A first step of detecting the distance to the subject using a photoelectric conversion means different from the imaging means at a predetermined time interval prior to the operation of the focusing operation operation member for instructing the focusing operation; ,
    When the focusing operation member is operated, the reference position is calculated using the distance measurement result of the first step, and the sampling range for detecting the contrast of the subject is narrower than the entire area. In addition, the range before and after the sampling position corresponding to the distance to the subject detected in the first step is set to be narrow when the lens system is wide according to the focal length of the lens system, A second step that is set wider as
    A third step of detecting an in-focus position within the set sampling range by moving the lens system in the vicinity of the reference position calculated in the second step using the imaging means;
    A fourth step of detecting the in-focus position of the lens system by detecting the distance to the subject using the photoelectric conversion means;
    A fifth step of determining a final focus position based on the focus position detected in the third step and the fourth step;
    Including
    The in-focus position detecting method, wherein the third step and the fourth step are performed substantially simultaneously.
  17. A computer-readable recording medium on which a program for causing a computer to execute each step of the invention according to any one of claims 10 to 16 is recorded.
JP2000058838A 2000-03-03 2000-03-03 Automatic focusing device, digital camera, portable information input device, focusing position detection method, and computer-readable recording medium Expired - Fee Related JP3820076B2 (en)

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JP2000058838A JP3820076B2 (en) 2000-03-03 2000-03-03 Automatic focusing device, digital camera, portable information input device, focusing position detection method, and computer-readable recording medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000058838A JP3820076B2 (en) 2000-03-03 2000-03-03 Automatic focusing device, digital camera, portable information input device, focusing position detection method, and computer-readable recording medium

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JP4478377B2 (en) 2002-09-03 2010-06-09 キヤノン株式会社 Automatic focusing method and imaging apparatus
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JP6087617B2 (en) * 2012-12-21 2017-03-01 キヤノン株式会社 Imaging apparatus and control method thereof

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