JP3761318B2 - Imaging device adjustment system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus adjustment system, and more particularly, to an imaging apparatus adjustment system that adjusts an imaging apparatus that performs imaging by controlling a zoom lens and a focus lens.
[0002]
[Prior art]
Conventionally, as this type of autofocus device, so-called hill-climbing is performed in which a high-frequency component is extracted from an image pickup signal obtained from an image sensor such as a CCD, and auto-focusing is performed by driving a photographing lens so that this high-frequency component becomes maximum The method is known.
[0003]
Such an autofocus adjustment method does not require a special optical member for focus adjustment to detect the amount of deviation of the image that changes in accordance with the light emission / light reception of the infrared rays or the focus state, and the distance can be at a distance or near. It has the advantage of being able to focus accurately without depending on.
[0004]
In recent years, various improvements have been proposed for such an autofocus adjustment method. For example, in Japanese Patent Laid-Open No. 64-077008, by selecting an algorithm for determining a lens driving focus amount from a defocus amount for a plurality of areas of a shooting screen according to a relative position distribution of a subject, A technique for improving the probability of focusing on a subject to be photographed is disclosed.
[0005]
Japanese Patent Laid-Open No. 1-287512 discloses a probability that focus detection can be performed by switching an algorithm that determines a lens driving focus amount from a defocusing amount for a plurality of regions on a shooting screen according to a camera sequence. Techniques for enhancing are disclosed.
[0006]
In Japanese Patent Laid-Open No. 4-145404, a value obtained by adding a feed amount obtained by a calculation means to a feed amount corresponding to a detected zoom lens position is used as a feed control from the reference position to the focus lens focus position. There is disclosed a technique that enables infinite position adjustment and high-precision focusing control that are electrically easy by performing control as a quantity.
[0007]
In Japanese Patent Laid-Open No. 4-130408, the infinite position of the focusing lens group, which changes depending on the extension position of the variable magnification lens group, is electrically stored in the storage means, thereby eliminating the need for functional position adjustment on the assembly line. The technology is disclosed.
[0008]
[Problems to be solved by the invention]
By the way, in general, in an imaging apparatus that samples an AF evaluation value while moving a focus lens system and detects an in-focus position based on a sampling result of the AF evaluation value, when adjusting the lens position, At the sampling interval, there is a problem that the quantization error is large and the adjustment accuracy is not very good.
[0009]
In addition, the conventional imaging apparatus has a problem that the AF operation is performed for a long time and cannot be focused in a short time.
[0010]
The present invention has been made in view of the above, and an object thereof is to provide an image pickup apparatus adjustment system in which a quantization error at the time of lens position adjustment is reduced.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, the present invention provides an image pickup apparatus adjustment system that adjusts an image pickup apparatus that picks up an image by controlling a zoom lens and a focus lens and obtains a digital video signal by picking up an object. Storing adjustment means for adjusting the position of the focus lens with respect to the position of the zoom lens, and evaluation means for obtaining an AF evaluation value from a luminance signal included in the digital video signal obtained by the imaging means A table, sampling means for sampling the AF evaluation value obtained by the evaluation means while moving the position of the focus lens based on the table, and the focus lens based on the sampling result of the sampling means Focusing means for driving control and focusing on a subject at an arbitrary distance Adjustment data calculation means for calculating the adjustment data based on the position and writing the adjustment data to the table, and the adjustment data calculation means, when calculating the adjustment data, compared with the time of normal imaging, The amount of movement of the focus lens at each sampling when sampling the AF evaluation value is reduced.
[0012]
Further, according to the present invention, when calculating the adjustment data, first, an approximate in-focus position is set with the movement amount of the focus lens at the time of each sampling when sampling the AF evaluation value as a first value. Then, the in-focus position is obtained by setting the movement amount to be smaller than the first value from the vicinity of the approximate in-focus position.
[0013]
According to another aspect of the present invention, there is provided an imaging apparatus adjustment system that adjusts an imaging apparatus that captures an image by controlling a zoom lens and a focus lens, an imaging unit that captures an image of a subject and obtains a digital video signal, An evaluation unit that obtains an AF evaluation value from a luminance signal included in the video signal, a sampling unit that samples the AF evaluation value obtained by the evaluation unit while moving the position of the focus lens, and a sampling result of the sampling unit A focusing unit that drives and controls the focus lens to a focusing position, a focusing position correcting unit that corrects the focusing position by a correction amount for correcting lens tilt, spherical aberration, and the like; and the correction amount Correction amount calculating means for calculating the AF evaluation value, wherein the correction amount calculating means samples the AF evaluation value. Change the that area, and calculates the correction amount based on the focus position with respect to any distance to the subject.
[0014]
Further, in the present invention, the correction amount calculation means first obtains an approximate in-focus position using the movement amount of the focus lens at the time of each sampling when sampling the AF evaluation value as a first value, The in-focus position is obtained from the vicinity of the approximate in-focus position by setting the movement amount to be smaller than the first value.
[0015]
The present invention also provides an imaging device that captures an image of a subject and obtains a digital video signal in an imaging device that controls a zoom lens and a focus lens, and a luminance signal included in the digital video signal obtained by the imaging device. An evaluation means for obtaining an AF evaluation value from the table, a table storing adjustment data for adjusting the position of the focus lens with respect to the position of the zoom lens, and the position of the focus lens while moving based on the table Sampling means for sampling the AF evaluation value obtained by the evaluation means, and focusing means for driving and controlling the focus lens to a focus position based on a sampling result of the sampling means, and sampling the AF evaluation value First, the focus lens at the time of each sampling The approximate focus position is obtained with the movement amount as the first value, and then the focus position is obtained from the vicinity of the approximate focus position with the movement amount being smaller than the first value. .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described below in detail in the order of [imaging device], [imaging device adjustment system], and [lens position adjustment] with reference to the accompanying drawings.
[0017]
[Imaging device]
The configuration of the imaging apparatus of the present invention will be described. FIG. 1 is a block diagram showing an internal configuration of an imaging apparatus according to an embodiment of the present invention.
[0018]
FIG. 1 is a configuration diagram of an imaging apparatus to which the autofocus apparatus according to the present embodiment is applied. In the figure, reference numeral 100 denotes an image pickup apparatus. The image pickup apparatus 100 includes a lens system 101, a mechanical mechanism 102 including a diaphragm / 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, and a motor driver 135 are provided. A detachable PC card 150 is connected via the PC card interface 112.
[0019]
The lens unit includes a mechanical mechanism 102 including a lens 101 system, a diaphragm / filter unit, and the 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.
[0020]
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 131 drives the pulse motor 132 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.
[0021]
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 the noise of the CCD type image pickup device.
[0022]
In addition, the AGC amplifier 105 corrects the level of the signal that has been correlated and sampled by the CDS circuit 104. 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.
[0023]
Also, 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. Data processing for various processing, correction, and image compression / decompression is performed separately for color difference (Cb, Cr) and luminance (Y). The DCT 108 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.
[0024]
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.
[0025]
The CPU 121 uses the RAM as a work area in accordance with a program stored in the ROM, and controls all operations inside the imaging apparatus 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.
[0026]
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 to the inside of the imaging apparatus.
[0027]
The display unit 122 is implemented 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 includes buttons for externally performing function selection, shooting instruction, and other various settings. In the EEPROM 130, adjustment data and the like used when the CPU 121 controls the operation of the imaging apparatus are written.
[0028]
The above-described imaging apparatus 100 (CPU 121) has 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 adjustment data in the EEPROM 130. An adjustment mode for writing is provided.
[0029]
FIG. 2 is a diagram illustrating an example of a specific configuration of the IPP 107. As shown in FIG. 2, 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, 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 that separates 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). It includes a video signal processing unit 1078 to be output to the form display unit 122, a.
[0030]
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. BPF 1080 to be output, an AF evaluation value circuit 1081 that outputs a digital count value corresponding to the luminance data (Y) passed through BPF 1080 to the CPU 121 as an AF evaluation value, and luminance data (Y) detected by the Y operation unit 1079 An AE evaluation value circuit 1082 that outputs a digital count value to the CPU 121 as an AE evaluation value, and a Y calculation unit that detects luminance data (Y) of each of R, G, and B image data after gain adjustment by the digital gain adjustment unit 1075 1083 and the digital data corresponding to the luminance data (Y) detected by the Y operation unit 1083. And AWB evaluation value circuit 1084 which outputs a cement value to CPU 121 as the AWB evaluation value, and a CPUI / F1085 is an interface with the CPU 121, and the DCTI / F1086 such an interface with the DCT108.
[0031]
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 the reference value. In this embodiment, a description will be given assuming that the diaphragm is fixed (F4; Av4) as an example.
[0032]
In the AF control, after the shutter speed and the gain are set, the AFM (pulse motor) is driven by a specified pulse in a 1 Vd period. During the prescribed pulse drive, the digital video signal obtained in the IPP is processed to obtain a luminance signal. An AF evaluation value is obtained by integrating high frequency components from the luminance signal by the filter means. The peak of this AF evaluation value is in focus.
[0033]
In zoom control, the ratio of which position (distance) the current focus position is from a set value “fp far calc” (infinite), which will be described later, to a set value “fp near calc” (closest; about 0.2 m) Is required. The focus position is driven to a focus position having the same ratio from “fp far def” and “fp near def” at the zoom point together with the zoom drive, and the focus shift due to the zoom of the varifocal lens is corrected.
[0034]
Next, each set value that is an adjustment value will be described. FIG. 3 is a diagram for explaining the set values. As shown in FIG. 3, the autofocus is performed using a varifocal lens having 9 zoom steps (positions) from 00 to 08. The shooting distance range is from infinity to about 0.2 m, but only wide is about 0.01 m.
[0035]
In the table shown in FIG. 3, “ccdaf drv data”, “fp far def”, “fp near def”, “fp far calc”, and “fp near calc” are set as six types of setting values for each zoom step. , “Nml smp”. Each set value in FIG. 3 is displayed in hexadecimal.
[0036]
Here, “ccdaf drv data” indicates the amount of movement (number of pulses) of the focus lens system for each sampling when the AF evaluation value is sampled. “Fp far def” indicates an AF evaluation value sampling start position at each zoom step, and a difference based on the position of the focus extension pulse number “fp inf def” is input as data.
[0037]
“Fp near def” indicates the AF evaluation value sampling end position at each zoom step, and a difference based on the position of the focus extension pulse number “fp inf def” is input as data. “Fp far calc” indicates an infinite position in each zoom step, and a difference based on the position of the focus extension pulse number “fp inf def” is input as data.
[0038]
“Fp near calc” indicates a 0.2 m position in each zoom step, and a difference based on the position of the focus extension pulse number “fp inf def” is input as data. “Nml smp” indicates the number of samplings for performing the entire-range sampling focus lens system movement in which the AF evaluation value is always sampled regardless of the AF evaluation value sampling result.
[0039]
Note that “fp inf def” indicates the number of focus extension pulses from the infinite side mechanical end of the focus to the start of wide AF evaluation value sampling.
[0040]
Next, the relationship between the zoom position and the focus position will be described. FIG. 4 is a view showing a ZF table for focus position adjustment, and FIG. 5 is a view showing the ZF (zoom focus) table of FIG. 4 in a graph.
[0041]
The ZF table is used when adjusting the focus position with respect to the zoom position. The ZF table shown in FIG. 0, No. 1, No. 1 2 shows three examples. In any example, nine positions are assigned to the wide (W) end, the mean (M), and the tele (T) end with respect to two standards of infinite and close (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 the EEPROM 130. In this ZF table, no. 0 is the Min value, No. 1 is the Typ value, No. 1 2 shows the Max value. 0-No. A value of 2 is written in advance as an adjustment initial value.
[0042]
In FIG. Infinite standard A0-1 and closest standard B0-1 are shown as a graph of 0. Infinite Standard A1-1 and Closest Standard B1-1 are shown as a graph of No. 1, The infinite reference A2-1 and the closest reference B2-1 are shown as a graph of 2. From the above graph, the number of pulses is lower in the case of using the close range as a reference than in the case of using infinity as a reference.
[0043]
Subsequently, the AF operation will be described. FIG. 6 is a flowchart for explaining the setting operation for performing the autofocus operation, and FIG. 7 is a flowchart for explaining the autofocus operation.
[0044]
In FIG. 6, fp far init = number of focus extension pulses (fp inf def) −AF evaluation value sampling start position (fp far def [zoom]), fp near init = number of focus extension pulses (fp inf def) + AF evaluation value sampling End position (fp near def [zoom]), fp home = (fp far init) − (fp home def), and nml smp def = nml smp [zoom]. Here, zoom is a position of 9 zoom steps. When zoom = 0, “zoom” becomes “wide”, when zoom = 4, “mean”, and when zoom = 8, “tele”.
[0045]
In the operation illustrated in FIG. 6, first, zoom reset is performed by combining the zoom position and the zoom drive pulse number, and then focus reset is performed by combining the focus position and the focus drive pulse number. Zoom reset and focus reset are performed by driving to the mechanical end.
[0046]
The position after driving with the number of pulses greater than that driven to the mechanical end is determined as the prescribed pulse number position. Here, in the case of focus, fp max = 205 pulses at the near mechanical end. The last pulse output data when driving to the mechanical end is set as fp home state at the time of adjustment. Subsequently, the focus is set to the normal focus position (about 2.5 m), and further zooming is performed.
[0047]
Subsequently, the operation shown in FIG. 7 is started. The operation mode shown in FIG. 7 is an autofocus mode. In the case of autofocus, first, AF initial setting (ccdaf init set) is executed (step S1), and the first release is operated. At this time, the normal focus position (about 2.5 m) at the set zoom point is calculated from the adjustment value, and the AF operation is performed. Subsequently, the AF AE is set (ccdaf ae set) (step S2).
[0048]
When the process proceeds to step S3, the focus is driven to the home position HP (fp home). In the subsequent step S4, the focus is driven to the initial position INIT (fp far init). As described above, the focus is driven from the home position HP to the initial position INIT, so that the backlash (fp b brush = 8 (pulse)) can be removed.
[0049]
Then, the process proceeds to step S5. Focus drive during AF evaluation value sampling is performed in synchronization with the vertical synchronization signal Vd. At this time, the focus is driven by the amount of movement (ccdaf drv data) of the focus lens system for each sampling. At this time, the focus drive is performed until the AF evaluation value corresponding to nml smp is sampled regardless of the value of the AF evaluation value (information such as a peak). The focus drive amount is (ccdaf drv data ) * (Becoming nml smp)). This is within the normal shooting distance range (from infinite to about 0.5 m).
[0050]
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 the in-focus position is within the normal shooting distance range. 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.
[0051]
Thereafter, the process proceeds to step S6. In step S6, when the in-focus position is within the normal shooting distance range, the AF evaluation value sampling is stopped, and the focus is driven from the in-focus position to the position where the backlash is removed. Driven.
[0052]
In addition, when there is no in-focus position within the normal shooting distance range, AF evaluation value sampling within the macro shooting distance range (about 0.5 m to about 0.2 m) is performed (macro; up to fp near init) ). However, within the macro shooting distance range, sampling of the AF evaluation value is stopped when a peak is detected.
[0053]
Thereafter, the process proceeds to step S7. In step S7, the focus drive is turned off (fcsm off), and the process is terminated.
[0054]
FIG. 8 is a timing chart showing the correspondence between the AF evaluation value sampling timing and the focus pulse motor drive timing. FIG. 8A shows a timing chart regarding NTSC in which the vertical synchronization signal Vd is 1/30 Hz (33 mS). FIG. 2B shows a timing chart regarding PAL (television: TV) having Vd of 1/25 Hz (40 mS). FIG. 4C shows a timing chart regarding a PAL (liquid crystal: LCD) whose vertical synchronizing signal Vd is 1/36 Hz (28 mS).
[0055]
According to the above timing chart, the pulse intervals of the AF evaluation value sampling timing ST and the focus pulse motor drive timing WT (wide) and TT (tele) are changed as the pulse interval of the vertical synchronization signal Vd increases. That is, when the NTSC in FIG. 8A is taken as a reference, the NTSC is 1/30 Hz, whereas the PAL (TV) in FIG. 8B is 1/25 Hz and the pulse width is increased. Accordingly, the pulse interval between the AF evaluation value sampling ST and the focus pulse motor drive timings WT and TT is wider in the PAL (TV) than in the case of NTSC.
[0056]
On the other hand, when the NTSC in FIG. 8A is taken as a reference, the NTSC is 1/30 Hz, whereas the PAL (LCD) in FIG. Therefore, the pulse interval between the AF evaluation value sampling ST and the focus pulse motor drive timings WT and TT is narrower in the PAL (LCD) than in the case of NTSC.
[0057]
Next, the driver will be described in detail. 9 is a circuit diagram showing a driver of the zoom pulse motor and the focus pulse motor, FIG. 10 is a diagram showing a truth table of the pulse motor driving IC, and FIG. 11 is a pulse at the time of autofocus execution in the driver shown in FIG. It is a timing chart which shows a waveform by simulation. In FIG. 9, the focus driver 131 and the zoom driver 133 define the input / output relationship according to the truth table shown in FIG.
[0058]
According to the truth table shown in FIG. 10, the focus driver 131 and the zoom driver 133 have no input (IN1, 2) when the enable signal of their circuits is “L” (low), and the standby state Therefore, 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 generate an output in which two-phase excitation changes due to the logical relationship between the inputs IN1 and IN2. Here, FIGS. 11A, 11B, and 11C show pulse waveforms during wide operation, mean operation, and tele operation during AF execution, respectively. Comparing the above pulse waveforms, the enable time becomes longer in the order of wide, mean, and tele, and accordingly, the driving time of the driver becomes longer.
[0059]
[Imaging device adjustment system]
FIG. 12 is a diagram illustrating an external configuration of the imaging apparatus adjustment apparatus 200 according to the present embodiment, and FIG. 13 illustrates a block configuration of an imaging apparatus adjustment system 300 including the imaging apparatus 100 and the imaging apparatus adjustment apparatus 200. FIG.
[0060]
An imaging apparatus adjustment apparatus 200 shown in FIGS. 12 and 13 includes an imaging apparatus supply power supply 201 that supplies power to the imaging apparatus 100, an adapter 202 for GPIB control of the imaging apparatus supply power supply 201, and the imaging apparatus 100. A monitor 203 for displaying a captured image, a vector scope 204 for displaying the amplitude and phase of a color signal (RGB) scanned by the imaging apparatus 100 in a vector, a wave form monitor 205 for video signal observation of the monitor 203, A light source 206 for a chart, a computer 207 for controlling the imaging apparatus 100 and the above measuring devices (such as the vector scope 204 and the wave form monitor 205), and a display 208 that is a display device of the computer 207 and displays an adjustment menu and the like G installed in the computer 207 main body An IBI / F 209, an adjustment jig main body (jig base) 210 that fixes the image pickup apparatus 100 and connects the image pickup apparatus supply power 201, RS-232C, VIDEO, and the like, and a control box 211 are provided. .
[0061]
[Lens position adjustment]
Next, lens position adjustment, which is the gist of the present invention, will be described. Lens position adjustment refers to adjusting the pulse motor position at the time of lens assembly, the arbitrary shooting distance of the lens (infinite, close distance, etc.), the variation in the lens extension position, and individual variations in the lens or lens extension mechanism It is. This lens position adjustment is usually performed at the time of factory shipment or by a service person.
[0062]
In the present embodiment, a focusing chart is placed at an arbitrary shooting distance to focus, and the lens position for the arbitrary shooting distance at that time is infinite (focusing device sampling start position when using the camera) and close (using the camera) The focusing device sampling end position at the time).
[0063]
The procedure for adjusting the position of the lens of the imaging apparatus 100 will be described with reference to the flowchart shown in FIG. FIG. 14 is a flowchart for explaining the procedure of lens position adjustment.
[0064]
First, in FIG. 14, the imaging apparatus 100 is mounted on the jig body 210 of the imaging apparatus adjustment apparatus 200 (step S11), and the imaging apparatus 100 and the imaging apparatus adjustment apparatus 200 are turned on (step S12). Then, the chart is set at a position of Acm (for example, 102.3 cm) from the imaging device (step S13).
[0065]
Then, the zoom lens is moved to the T end (step S14). Then, after moving the zoom lens to the T end (Z8), the above-described AF operation (CCDAF function in FIG. 7) is started (step S15). In the AF operation, the table shown in FIG. 15 is used. The table shown in FIG. 14 is different from the table shown in FIG. 3 in the values of “ccdaf drv data” and “nml smp”, and the AF evaluation value determined by (ccdaf drv data) × (nml smp) is set. The driving amount of the focus lens system for each sampling when sampling is smaller than the value of (ccdaf drv data) × (nml smp) in the table of FIG. That is, at the time of lens position adjustment, the moving amount of the focus lens system for each sampling when sampling the AF evaluation value is smaller than the moving amount at the time of actual imaging.
[0066]
The focus step position (Tn) at this time is read (step S16). The fp value of Tn -2.2 (number of pulses from ∞ to A) is set as the T-end Inf position (Tinf) (step S17).
[0067]
Subsequently, the chart is set at a position where the distance from the imaging device 100 is Bcm (for example, 35.8 cm) (step S18). Then, after the zoom lens is moved to the W end (Z0) (step S19), the above-described AF operation (CCDAF function in FIG. 7) is started (step S20). Also in this case, the table of FIG. 15 is used as in step S15.
[0068]
Next, the focus step position (Wn) at this time is read (step S21). The value -8 (number of pulses from ∞ to B) of Wn is set as the W end Inf position (Winf) (step S22). Then, the W∞ position is calculated from Tinf and Winf, data to be written in the ZF table is determined (step S23), and the adjustment data is written in the ZF table (step S24). Subsequently, the imaging apparatus 100 and the imaging apparatus adjustment apparatus 200 are turned off (step S25), and the imaging apparatus 100 is removed from the jig body 210 of the imaging apparatus adjustment apparatus 200 (step S26).
[0069]
Next, a method for shortening the lens position adjustment time will be described. In order to reduce the sampling error during adjustment, the sampling interval may be reduced. However, if the sampling interval is reduced, time (adjustment time) is required. Thus, first, the sampling interval is increased to obtain an approximate in-focus position, and then the final in-focus position is obtained by reducing the sampling interval in the vicinity of the approximate in-focus position. Thereby, both adjustment accuracy and adjustment time can be achieved. FIG. 16 is a flowchart for explaining a procedure for shortening the lens position adjustment time.
[0070]
First, as shown in FIG. 16, the in-focus position at 1 AF step pulse 3 is obtained (step S31). Next, -12 is set to HP and -3 pulse is set to infinity from the in-focus position in the 1AF step 3 pulse (step S32). Then, the in-focus position in 1 AF step 1 pulse is obtained (step S33). The method for obtaining the in-focus position is performed by executing the same AF operation (CCDAF main function shown in FIG. 7) as described above.
[0071]
Similarly, in the case where the AF operation is performed during normal imaging of the imaging apparatus 100, first, after obtaining the approximate focus position by increasing the sampling interval, sampling is performed in the vicinity of the approximate focus position. The final focus position may be obtained by reducing the interval.
[0072]
By the way, in order to correct the tilt of the lens, spherical aberration, and the like, there is a case where the position where correction is desired from the focus position using the light beam at the center of the lens is taken as the focus position. In order to obtain this correction amount, the area for sampling the AF evaluation value is changed, and this correction amount is obtained from the in-focus position of each sampling area. FIG. 17 is a flowchart showing a procedure for calculating the correction amount. FIG. 18 is an explanatory diagram for explaining the sampling area of the CCD 103.
[0073]
As shown in FIG. 18A, the CCD 103 is divided into 48 areas of 8 × 6. FIGS. 18B to 18F show sampling areas at the center of the screen, upper left, upper right, lower left, and lower right, and each sampling area is 1/12 of the whole.
[0074]
In FIG. 18, first, the AF evaluation value sampling area is set to the center of the screen shown in FIG. 18B, and the in-focus position at the center of the screen is obtained (step S41). Next, the AF evaluation value sampling area is set to the upper left of the screen shown in FIG. 18C, and the in-focus position at the upper left of the screen is obtained (step S42). Then, the AF evaluation value sampling area is set to the upper right of the screen shown in FIG. 18D, and the in-focus position at the upper right of the screen is obtained (step S43). Further, the AF evaluation value sampling area is set to the lower left of the screen shown in FIG. 18E, and the in-focus position at the lower left of the screen is obtained (step S44). Finally, the lower right corner of the screen shown in FIG. 18F is obtained, and the in-focus position at the lower right corner of the screen is obtained (step S45). The method for obtaining the in-focus position is performed by executing the CCDAF main function (see FIG. 7) in the same manner as described above. Then, the average of the in-focus positions of the AF sampling areas at the upper left of the screen, the upper right of the screen, the lower left of the screen, and the lower right of the screen is obtained, and the difference from the in-focus position at the center of the screen is written in the EEPROM 130 as spherical aberration (correction amount).
[0075]
It should be noted that there is a case where the center and peripheral focus cannot be improved unless the correction amount of the lens tilt or spherical aberration is equal to or less than 1 AF step (usually, the 1 AF step is the focal length and the depth of field of the shooting distance). Is within.) Therefore, the correction amount for lens tilt, spherical aberration, and the like may be obtained within 1 AF step.
[0076]
As described above, in the present embodiment, when calculating the adjustment data to be written in the ZF table used when adjusting the focus position with respect to the zoom position, compared to the AF operation during normal shooting, Since the amount of movement of the focus lens system for each sampling of the AF evaluation value is reduced, adjustment in the completed state of the imaging apparatus is possible, and quantization error during lens position adjustment can be reduced. Become.
[0077]
Further, in the present embodiment, when calculating the adjustment data to be written in the ZF table, first, an approximate in-focus position is obtained by increasing the amount of movement of the focus lens system, and then in the vicinity of the approximate in-focus position. Thus, since the in-focus position is obtained by reducing the amount of movement of the focus lens system, the adjustment time can be shortened while maintaining high adjustment accuracy.
[0078]
In the present embodiment, the correction amount for correcting lens tilt, spherical aberration, and the like is obtained from the focus position of each sampling area by changing the AF evaluation value sampling area. In addition, it is possible to calculate a correction amount for correcting lens tilt and spherical aberration.
[0079]
The imaging apparatus according to the present invention described above can be widely applied to digital cameras, digital video cameras, and the like.
[0080]
In addition, this invention is not limited to the said embodiment, In the range which does not change the summary of invention, it can change suitably.
[0081]
【The invention's effect】
As described above, the present invention provides an imaging apparatus adjustment system that adjusts an imaging apparatus that captures an image by controlling a zoom lens and a focus lens, an imaging unit that captures a subject and obtains a digital video signal, and an imaging unit. An evaluation means for obtaining an AF evaluation value from a luminance signal included in the received digital video signal, a table storing adjustment data for adjusting the position of the focus lens with respect to the position of the zoom lens, and a focus based on the table Sampling means for sampling the AF evaluation value obtained by the evaluation means while moving the position of the lens, focusing means for driving and controlling the focus lens to the in-focus position based on the sampling result of the sampling means, and an object at an arbitrary distance Calculate adjustment data based on the in-focus position for Adjustment data calculation means, and when the adjustment data is calculated, the adjustment data calculation means moves the focus lens at each sampling time when sampling the AF evaluation value, as compared with normal imaging. Since the amount is reduced, the image pickup apparatus can be adjusted in a completed state, and the quantization error during lens position adjustment can be reduced.
[0082]
Further, in the present invention, when calculating the adjustment data, first, an approximate in-focus position is obtained using the movement amount of the focus lens at the time of sampling when sampling the AF evaluation value as a first value, Since the in-focus position is obtained from the vicinity of the approximate in-focus position with the movement amount being smaller than the first value, the adjustment time can be shortened while maintaining high adjustment accuracy. .
[0083]
The present invention also relates to an image pickup apparatus adjustment system for adjusting an image pickup apparatus for picking up an image by controlling a zoom lens and a focus lens, an image pickup means for picking up a subject and obtaining a digital video signal, and a digital video obtained by the image pickup means An evaluation unit that obtains an AF evaluation value from a luminance signal included in the signal, a sampling unit that samples an AF evaluation value obtained by the evaluation unit while moving the position of the focus lens, and a focus lens based on a sampling result of the sampling unit Focusing means for driving the lens to the in-focus position, in-focus position correcting means for correcting the in-focus position by a correction amount for correcting lens tilt, spherical aberration, etc., and correction amount calculation for calculating the correction amount And a correction amount calculating means is configured to change an area for sampling the AF evaluation value to change an arbitrary distance. Since it was decided to calculate the correction amount based on the focus position with respect Utsushitai, it is possible to calculate a correction amount for correcting such inclination and spherical aberration of the exact lens.
[0084]
Further, according to the present invention, the correction amount calculating means first obtains an approximate in-focus position using the movement amount of the focus lens at the time of sampling when sampling the AF evaluation value as a first value, and then calculates the approximate Since the in-focus position is obtained from the vicinity of the in-focus position with the movement amount being smaller than the first value, the quantization error can be reduced, and a more accurate correction amount can be calculated. It becomes possible.
[0085]
The present invention also relates to an imaging device that controls a zoom lens and a focus lens and captures an image of a subject to obtain a digital video signal, and a luminance signal included in the digital video signal obtained by the imaging unit. An evaluation means for obtaining an AF evaluation value, a table storing adjustment data for adjusting the position of the focus lens with respect to the position of the zoom lens, and an evaluation means obtained by moving the position of the focus lens based on the table Sampling means for sampling the AF evaluation value, and focusing means for driving and controlling the focus lens to the in-focus position based on the sampling result of the sampling means. When sampling the AF evaluation value, The amount of movement of the focus lens at each sampling is set as the first value and approximate Since the position is obtained and then the in-focus position is obtained from the vicinity of the approximate in-focus position with the movement amount being smaller than the first value, the AF operation is performed while maintaining the in-focus position accuracy high. Time can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an internal configuration of an imaging apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of a specific configuration of the IPP in FIG.
FIG. 3 is a diagram illustrating a table storing setting values.
FIG. 4 is a diagram illustrating a ZF table used when adjusting a focus position with respect to a zoom position.
FIG. 5 is a diagram showing the ZF table of FIG. 5 in a graph.
FIG. 6 is a flowchart illustrating a setting operation for performing an autofocus operation.
FIG. 7 is a flowchart illustrating an autofocus operation.
FIG. 8 is a timing chart showing a correspondence relationship between AF evaluation value sampling timing and focus pulse motor drive timing.
FIG. 9 is a circuit diagram showing drivers of a zoom pulse motor and a focus pulse motor.
10 is a diagram showing a truth table of a pulse motor driving IC in the driver shown in FIG. 8. FIG.
11 is a timing chart showing, by simulation, a pulse waveform when autofocus is executed in the driver shown in FIG.
FIG. 12 is a diagram illustrating a configuration of an imaging apparatus adjustment apparatus.
FIG. 13 is a diagram illustrating a configuration of an imaging apparatus adjustment system.
FIG. 14 is a flowchart for explaining a procedure of lens position adjustment;
FIG. 15 is a diagram showing another example of the table in FIG. 3;
FIG. 16 is a flowchart for explaining a procedure for shortening the adjustment time of the lens position adjustment;
FIG. 17 is an explanatory diagram for explaining a CCD sampling area, which is a flowchart showing a procedure for calculating a correction amount;
FIG. 18 is an explanatory diagram for explaining an AF evaluation value sampling area of a CCD.
[Explanation of symbols]
100 Imaging device
101 lens
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
150 PC card
200 Imaging device adjustment device
201 Power supply for imaging device supply
202 adapter
203 monitor
204 Vectorscope
205 Wave Form Monitor
206 Luminance box
207 Computer
208 display
209 GPIBI / F
210 Adjustment jig body
211 Control BOX
300 Imaging device adjustment system
1071 Color separation unit
1072 Signal interpolation unit
1073 Pedestal adjustment unit
1074 White balance adjustment section
1075 Digital gain adjustment unit (digital gain adjustment means)
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 (2)

In an imaging apparatus adjustment system that adjusts an imaging apparatus that controls an image by controlling a zoom lens and a focus lens,
Imaging means for capturing a subject and obtaining a digital video signal;
Evaluation means for obtaining an AF evaluation value from a luminance signal included in the digital video signal obtained by the imaging means;
Sampling means for sampling the AF evaluation value obtained by the evaluation means while moving the position of the focus lens;
A focusing unit that drives and controls the focus lens to a focusing position based on a sampling result of the sampling unit;
An in-focus position correcting means for correcting the in-focus position by a correction amount for correcting lens tilt, spherical aberration, and the like;
Correction amount calculating means for calculating the correction amount,
The imaging apparatus adjustment system according to claim 1, wherein the correction amount calculation means calculates the correction amount based on a focus position with respect to a subject at an arbitrary distance by changing an area where the AF evaluation value is sampled.   The correction amount calculation means first obtains an approximate in-focus position by using a movement amount of the focus lens at the time of sampling when sampling the AF evaluation value as a first value, and then calculates the approximate in-focus position. 2. The imaging apparatus adjustment system according to claim 1, wherein an in-focus position is obtained from the vicinity of the first position with the movement amount being smaller than the first value.

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