JPH099131A - Interchangeable lens type camera system - Google Patents

Abstract

PURPOSE: To provide the interchangeable lens system on which every type of lens such as fore-element focus type lens unit and inner focus type lens unit is mounted. CONSTITUTION: This system is provided with a magnification lens 102, a focus lens 105, a lens cam data memory 120 storing a relation of position of the focus lens to keep a focus state during the magnification, an AF signal processing circuit 113 extracting a focus signal equivalent to a signal within a focus detection area from image pickup outputted from image pickup element 106-108, and a lens microcomputer 116 controlling the magnification lens and the focus lens based on both an output of the lens cam data memory and an output of the AF signal processing circuit 113 to conduct magnification, and the lens microcomputer 116 and the lens cam data memory 120 are included in a lens unit and the output of the AF signal processing circuit 113 is given to the lens unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus suitable for use in a video camera having interchangeable lenses.

[0002]

2. Description of the Related Art In recent years, video equipment such as a video camera has made remarkable progress, and an interchangeable lens system has been introduced in the video camera as a part of its multifunction and high performance.

FIG. 9 is a block diagram showing an example of the configuration of a video camera to which this type of interchangeable lens system is applied.

In the conventional variable-magnification lens unit, the variable-magnification lens 21 and the correction lens 22 are mechanically connected by a cam, and when the variable-magnification operation is performed manually or electrically, the variable-magnification lens 21 and the correction lens 22. Move together.

These variable magnification lens 21 and correction lens 22
Are collectively called a zoom lens. In such a lens system, the front lens 1 serves as a focus lens, and the focus is adjusted by moving in the optical axis direction.

The light passing through these lens groups is imaged on the image pickup surface of the image pickup device 3, photoelectrically converted into an electric signal, and outputted as a video signal. This video signal is CDS / A
It is sampled and held (correlated double sampling) in the GC circuit 4 and amplified to a predetermined level by the AGC.
It is converted into digital video data by the / D converter 5, is input to a camera process circuit (not shown) in the subsequent stage and is converted to a standard television signal, and is also input to the AF signal processing circuit 6.

The AF signal processing circuit 6 extracts a high-frequency component that changes according to the focus state in the video signal and takes it in the control microcomputer 7 as an AF evaluation value.

The microcomputer 7 determines the drive speed of the focus motor according to the degree of focus and the motor drive direction such that the AF evaluation value increases, and the speed and direction of the focus motor are determined by the focus motor driver 9 in the lens unit 12. To drive the focus lens 1 via the focus motor 91.

The zoom switch 8 is in the state of the microcomputer 7
Read according to the operating state of the zoom switch 8,
The microcomputer 7 determines the drive direction and drive speed of the zoom lenses 21 and 22, and sends them to the zoom motor driver 11 in the lens unit 12 to drive the zoom lenses 21 and 22 via the zoom motor 12.

The camera body 13 can be separated from the lens unit 12, and the range of photography can be expanded by connecting another lens unit.

[0011]

By the way, in recent years, the integrated camera for consumer use is mechanically connected by a cam between the correction lens and the variable-magnification lens in order to downsize and enable photographing up to the front surface of the lens. The so-called inner function is used, in which the movement locus of the correction lens is previously stored in the microcomputer as lens cam data, the correction lens is driven according to the lens cam data, and the focus operation is also performed by the correction lens. Focus type lenses are becoming mainstream.

However, according to the technical idea in the above-mentioned conventional example, all the controls are performed on the camera side, and the lens unit side is driven according to the control signal supplied from the camera body. Therefore, if an inner focus type lens is to be realized in the lens unit of the interchangeable lens, the movement locus of the focus lens for correcting the change of the focal plane due to the zoom operation and maintaining the in-focus state, that is, the lens cam data is acquired by the camera. Must be held on the body side.

However, it is extremely burdensome for the camera side to have this lens cam data which is different for each lens unit on the camera body side, and it is not realistic as the number of interchangeable lenses is large.

Therefore, an object of the present invention is to solve the above-mentioned problems and provide an interchangeable lens system capable of connecting not only the front lens focus type but also any lens type such as an inner focus type lens unit. is there.

[0015]

In order to solve the above problems, according to the invention of claim 1 in the present application, a variable power lens for performing a variable power operation and a focusing state by the variable power operation are provided. A correction lens that corrects the focus for maintaining, a memory unit that stores the positional relationship between the variable power lens and the correction lens, and an image pickup that converts an image formed through the variable power lens and the correction lens into an electrical signal. Means, an extracting means for extracting a focus signal corresponding to one or a plurality of focus detection areas in the screen from the image pickup signal output from the image pickup means, and both of the memory means output and the extracting means. And a control unit that controls the variable power lens and the correction lens to perform a variable power operation on the basis of the variable power lens unit and the correction lens unit. It has means, and an interchangeable lens type camera system configured to deliver said extraction means output to the lens unit.

According to a second aspect of the present invention, in the first aspect, the extracting means is more specific than the image pickup signal corresponding to the focus detection area in the image pickup signal as the focus signal. It is configured to include a plurality of filter means for extracting the signal of the frequency component.

According to the invention of claim 3 in the present application, the extracting means is further provided with means for detecting a peak hold output obtained by peak-holding the luminance component of the image pickup signal corresponding to the focus detection area. The configuration.

Further, according to the invention of claim 4 in the present application, the extracting means is further provided with means for detecting a contrast component of the image pickup signal corresponding to the inside of the focus detection area.

According to the invention of claim 5 in the present application, the extraction means detects the contrast component by peak-holding the difference between the maximum value and the minimum value of the luminance component in the focus detection area. The structure is provided with peak hold means.

According to the invention of claim 6 in the present application, a variable power lens for performing a variable power operation, a correction lens for correcting a focus for maintaining a focused state in the variable power operation, and the variable power Memory means for storing a positional relationship between a lens and the correction lens, image pickup means for converting an image formed through the variable power lens and the correction lens into an electric signal, a switch for operating a variable power operation, and the image pickup Extracting means for extracting a focus signal in one or a plurality of focus detection areas in the screen from the image pickup signal output from the means;
When the switch is operated, it has a control means for controlling the variable power lens and the correction lens based on both the output of the memory means and the extraction means to perform a variable power operation. The interchangeable lens type camera system has the control means and the memory means in the lens unit including the correction lens means, and delivers the output of the extraction means and the state of the switch to the lens unit.

According to a seventh aspect of the present invention, in the lens unit detachable from the camera body, a variable power lens for performing a variable power operation, a focus lens for performing focus adjustment, and Memory means for storing the position information of the focus lens for maintaining the in-focus state during the zooming operation, and the focus state evaluation value signal and the zooming operation instruction information transmitted from the camera body side. In the case where the receiving means and the instruction information for the zooming operation are received by the receiving means, the zooming lens and the correction are performed based on both the storage information of the memory means and the evaluation value signal of the focus state. A lens unit including a control unit that controls a lens to perform a magnification change operation.

According to the invention of claim 8 in the present application, a camera in which the lens unit is attachable / detachable,
Extraction means for extracting a focus signal from an image pickup signal corresponding to one or a plurality of focus detection areas on the screen, instruction means for instructing a scaling operation, operation state of the instruction means, and the extraction means of the extraction means. By providing a communication means for transmitting the output signal to the microcomputer in the lens unit, the camera capable of calculating the driving direction and the driving speed for driving the focus lens to the focal point on the lens unit side.

[0023]

According to the first aspect of the invention, the focus evaluation value corresponding to the inside of the focus detection area extracted by the extracting means from the camera body side is transferred to the lens unit side, and in the lens unit. Position information of the correction lens for correcting the focal position displaced along with the movement of the variable power lens during the variable power operation stored in the memory means, and the driving speed of the correction lens based on the focus evaluation value, The direction is determined.

According to the second to fifth aspects of the present invention, the specific frequency component, the peak value of the luminance component, and the contrast component in the image pickup signal are used as the evaluation value of the focus state, respectively, and the focus detection with higher accuracy is performed. It can be performed.

According to the invention of claim 6, in addition to the structure of claim 1 described above, the state of a switch for operating the output of the extracting means and the zooming operation is transferred to the lens unit, thereby performing the zooming operation. Since the control means is in the lens unit, it is possible to connect any lens type lens unit, regardless of any front lens or inner focus, and at the same time there is a magnification control means for every lens unit inside the lens unit. The camera body can be operated to change the magnification.

According to the present invention, the focus evaluation value signal transferred from the camera side and the movement of the variable power lens during the variable power operation stored in the memory means in the lens unit The driving speed and the driving direction of the focus lens are determined in the lens unit by using the position information of the focus lens for correcting the displaced focus position.

According to the invention described in claim 8, in the lens unit, the focus evaluation value and the zooming operation are performed from the camera body side so that the displacement of the focal plane due to the AF operation and the zooming operation is simultaneously corrected. Is transmitted to the control means in the lens unit.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration when the present invention is applied to an interchangeable lens type video camera.

In the figure, 127 is a lens unit,
Reference numeral 128 denotes a camera body, and the lens unit is detachably attached to the camera body, forming a so-called interchangeable lens system.

The light from the subject is reflected by the lens unit 127.
A fixed first lens group 101, a second lens group 102 for performing zooming, a diaphragm 103, a fixed third lens group 104, a focus adjustment function, and movement of a focal plane due to zooming. Pass through a fourth lens group 105 (hereinafter referred to as a focus lens) that also has a correction function for correction,
An image is formed on an image pickup device such as a CCD in the camera body.

The image pickup device in the camera body is provided for each of the three primary colors of red (R), green (G), and blue (B), and is a so-called three-plate type image pickup system.

Of the three primary colors, the red component is imaged on the image sensor 106, the green component is imaged on the image sensor 107, and the blue component is imaged on the image sensor 108.

The images formed on the image pickup devices 106, 107, 108 are photoelectrically converted into amplifiers 109, 1 respectively.
After being amplified to the optimum level with 10, 111 respectively,
The signal is input to the camera signal processing circuit 112, converted into a standard television signal and output to a video recorder (not shown), and at the same time, input to the AF signal processing circuit 113.

AF generated by the AF signal processing circuit 113
The evaluation value is read at a cycle of an integral multiple of the vertical synchronizing signal according to the data reading program 115 in the main body microcomputer 114 in the camera body and transferred to the lens microcomputer 116 on the lens unit side.

In the camera signal processing circuit 112, the level of the luminance signal is detected from the image pickup signal output from each image pickup element, and is transferred to the lens microcomputer 116 in the lens unit via the main body microcomputer 114, The iris driver 124 is controlled based on the brightness signal information, the IG meter 123 is driven, and the aperture 103 is controlled to open and close.

The aperture value of the aperture 103 is the encoder 1
It is detected by 29, is supplied to the lens microcomputer 116, and is used as depth of field information.

Further, the main body microcomputer 114 on the camera main body side
Reads the state of the zoom switch 130 and the AF switch (AF operation is performed when ON and manual focus state is performed when OFF) 131, and the state of the switch is transmitted to the lens microcomputer 116. Accordingly, the motor driver 122 is controlled according to the operation state of the zoom switch 130 to drive the zoom motor 121, and the zoom lens 102 is driven in the operated direction to perform the zoom operation.

In the lens microcomputer 116, the AF program 117 receives the state of the AF switch 131 and the AF evaluation value from the main body microcomputer 114, and when the AF switch 131 is on, the motor control program is based on this AF evaluation value. 118 is operated, the focus motor 125 is driven by the focus motor driver 126, and the focus lens 105 is moved in the optical axis direction to perform focusing.

On the other hand, the lens unit is an inner focus type, and since the focal plane is changed by driving the zoom lens 102, the focus lens 105 is driven according to a predetermined characteristic as the zoom lens 102 is driven. The operation of preventing blurring due to the displacement of the focal plane is performed in parallel.

Therefore, in the lens microcomputer 116, the lens cam data 120 in which the focus cam locus indicating the change of the focus position of the focus lens with respect to the change of the position of the zoom lens is stored for each object distance is provided in the ROM. .

A computer zoom program 119 is provided for reading out the lens cam locus to be followed by the focus lens from the lens cam data 120 during zoom operation and controlling the drive of the focus lens.

This computer zoom program 119
Is information from the microcomputer 114 on the camera body side,
When the AF switch 131 is off (manual focus mode) and the zoom switch 130 is pressed, information on the zoom direction operated by the zoom switch 130, the position of the zoom lens, and the position of the focus lens are set. Is specified by the driving amount of the motor or the position information detected by the encoder, and the focus cam locus to be followed by the focus lens during the zoom operation and its tracing direction are specified and read out from the lens cam data 120, and the focus lens The correction speed and direction associated with the zoom operation are calculated.

The information on the correction speed and the direction is supplied to the focus motor driver 126, the focus motor 125 is driven, and the focus lens is driven, so that the occurrence of blurring during the zoom operation is prevented.

When the AF switch 131 is on and the zoom switch 130 is pressed, it is necessary to keep the in-focus state even when the subject moves, so that the computer zoom program 119 uses the above-mentioned condition. Lens cam data 120 stored in the lens microcomputer
Not only the control by the
The AF evaluation value signal sent from
The zoom operation is performed while maintaining the position where the evaluation value is maximum.

That is, the computer zoom program 1
The correction speed and direction information associated with the zoom operation of the focus lens obtained by 19 and the focus lens drive speed and direction information based on the AF blur information output from the AF circuit 117 are added, The focus lens drive speed and drive direction are calculated and supplied to the focus motor driver 126.

When the AF switch 131 is on and the zoom switch 130 is not pressed, the AF evaluation value transmitted from the main body microcomputer 114 is received by the AF program 117 in the lens microcomputer 116.
Based on this AF evaluation value, the motor control program 118
Is operated, the focus motor 125 is driven by the focus motor driver 126, and the focus lens 105 is moved in the optical axis direction so as to maximize the AF evaluation value, thereby performing focusing.

The aperture value of the aperture 103 is the encoder 1
It is detected by 29, supplied to the lens microcomputer 116, and used as depth-of-field information for speed correction of the focus lens.

Next, the camera signal processing circuit 11 will be described with reference to FIG.
The AF signal processing circuit 113 in 2 will be described. The red (R), green (G), and blue (B) image pickup device outputs amplified by the amplifiers 108, 109, and 110 to the optimum levels are supplied to the AF signal processing circuit 113, and the A / D converter. At 206, 207 and 208, they are converted into digital signals respectively and sent to the camera signal processing circuit 112, and at the same time, they are respectively amplified to appropriate levels by amplifiers 209, 210 and 211 and added by an adder 208 for automatic focus adjustment. The luminance signal S5 for use is generated.

The luminance signal S5 is input to the gamma circuit 213 and is gamma-converted according to a preset gamma curve to produce a signal S6 in which the low luminance component is emphasized and the high luminance component is suppressed. Gamma converted signal S6
Is a low-pass filter with a high cutoff frequency (hereinafter L
TE-LPF 214 which is a PF) and FE-LPF 215 which is an LPF having a low cutoff frequency, and low-frequency components are extracted by the respective filter characteristics determined by the main body microcomputer 114 through the microcomputer interface 253. -LPF 214 output signal S7
And an output signal 8 of the FE-LPF 215 is generated.

The signals S7 and S8 are sent to the switch 216.
Then, it is selectively switched by a Line E / O signal which is a signal for identifying whether the horizontal line is an even number or an odd number, and is input to a high pass filter (hereinafter referred to as HPF) 217.

That is, the signal S7 is supplied to the HPF 217 for even lines and the signal S7 is supplied for odd lines.
8 to the HPF 217.

In the HPF 217, the main microcomputer 114 extracts only the high frequency components by the odd / even filter characteristics determined through the microcomputer interface 253, and the absolute value circuit 218 converts them into absolute values to obtain a positive signal. S9 is generated. That is, S9 is a signal which alternately indicates the levels of the high frequency components extracted by the filters having different filter characteristics on the even lines and the odd lines. As a result, different frequency components can be obtained by scanning one screen.

The signal S9 is supplied to peak hold circuits 225, 226 and 227 for detecting the peak values of the signals in the L frame, C frame and R frame, respectively, and the peaks of the high frequency components in the respective frames. The value is detected and input to the line peak hold circuit 231, and the peak value for each horizontal line is detected.

Here, the frame generation circuit 254, in accordance with a command supplied from the microcomputer 114 via the microcomputer interface 253, has gates L and C frames for focus adjustment at positions on the screen as shown in FIG. , R frame signals are generated.

The peak hold circuit 225 outputs a line E / O signal (microcomputer) (gate signal L for outputting the L frame output from the frame generation circuit 254) for controlling the M-frame and a signal for identifying whether the horizontal line is an even number or an odd number. (Generated by 114) is input, and the peak hold circuit 225 is initialized at the position of the upper left LR1 which is the head of the focus adjustment L frame as shown in FIG.
The signal S in each frame of either the even line or the odd line designated from 4 through the microcomputer interface 253
9 is peak-held, and at the lower right IR1, that is, when the scanning of the entire area for focus adjustment is completed, the peak-hold value in the frame is transferred to the area buffer 228 and TE / FE is set.
Generate a peak rating.

Similarly, the C frame and the Line E / O signal output from the frame generation circuit 254 are input to the peak hold circuit 226, and the peak hold is performed by the CR1 at the upper left which is the head of the C frame for focus adjustment shown in FIG. The circuit 226 is initialized and the microcomputer interface 253
The signal S9 in each frame of either the even line or the odd line designated through is peak-held, and at IR1, that is, when the scanning of the entire area for focus adjustment is completed, the peak hold in the frame is held in the area buffer 229. Transfer value T
E / FE peak evaluation value is generated.

Similarly, the peak hold circuit 227 is also provided.
The R frame output from the frame generation circuit 254 and the Line E / O signal are input to the R, and the peak hold circuit 227 is initialized by the upper left RR1 which is the head of the R frame for focus adjustment shown in FIG. The signal S9 in each frame of either the even line or the odd line designated through the microcomputer interface 253 is peak-held, and IR1 is set.
Then, that is, when the scanning of the entire area for focus adjustment is completed, the peak hold value in the frame is transferred to the buffer 230 to generate the TE / FE peak evaluation value.

The line peak hold circuit 231 is supplied with the signal S9 and the gate signal for generating the L frame, C frame, and R frame of the frame generation circuit 254, and is initialized at the horizontal start point in each frame. And the horizontal 1 of the signal S9 in each frame
Hold the peak value of the line.

Integrator circuits 232, 233, 234, 23
5, 236, 237 have a line peak hold circuit 2
31 outputs and a LineE / O signal which is a signal for identifying whether the horizontal line is an even number or an odd number are input to the integration circuits 232 and 235 at the same time as the L frame generation output from the frame generation circuit 254. The gate signal is the integrating circuit 23.
C output from the frame generation circuit output 254 to 3,236.
The gate signal for frame generation is input to the integration circuits 234 and 237 as the gate signal for R frame generation output from the frame generation circuit 254.

The integrator circuit 232 initializes the integrator circuit 232 in the upper left LR1 which is the head of the focus adjustment L frame, and outputs the output of the line peak hold circuit 231 immediately before the end of the even line in each frame. Add to register, IR
At 1, the peak hold value is transferred to the area buffer 238 to generate the line peak integral evaluation value.

The integrator circuit 233 initializes the integrator circuit 233 at each position of the upper left CR1 which is the head of the focus adjustment C frame, and immediately before the end of the even lines in each frame, the integration of the line peak hold circuit 231 is performed. Add the output to the internal register,
At IR1, the peak hold value is transferred to the buffer 239 and the line peak integral evaluation value is generated.

The integrator circuit 234 initializes the integrator circuit 234 at the upper left RR1 which is the head of the focus adjustment R frame, and outputs the output of the line peak hold circuit 231 immediately before the end of the even lines in each frame. IR1
Then, the peak hold value is transferred to the area buffer 240 and the line peak integral evaluation value is generated.

The integrating circuits 235, 236 and 237 respectively add the odd line data instead of adding the even line data respectively.
Area buffer 2
The result is transferred to 41, 242 and 243.

The signal S7 is the peak hold circuit 21.
9, 220, 221 and line maximum value hold circuit 24
4 and the line minimum value hold circuit 245.

The L-frame generation gate signal output from the frame generation circuit 254 is input to the peak hold circuit 219, and the peak hold circuit 219 is initialized by the upper left LR1 which is the head of the L frame. The signal S7 in the frame is peak-held, the peak-held result is transferred to the buffer 222 by IR1, and the brightness level (hereinafter referred to as the Y signal)
Generate a peak evaluation value of.

Similarly, the peak hold circuit 220 receives the gate signal for C frame generation output from the frame generation circuit 254, and initializes the peak hold circuit 220 by CR1 at the upper left which is the head of the C frame. , Signal S in each frame
7, the peak hold result is transferred to the buffer 223 by IR1, and the Y signal peak evaluation value is generated.

Similarly, the peak hold circuit 221
Receives the gate signal for R frame generation output from the frame generation circuit 254, initializes the peak hold circuit 221 at the upper left RR1 which is the head of the R frame, and peak holds the signal S7 in each frame. Then, at IR1, the buffer 22
The peak hold result is transferred to 4 and a Y signal peak evaluation value is generated.

The line maximum value hold circuit 244 and the line minimum value hold circuit 245 receive the gate signals for L frame, C frame, and R frame generation output from the frame generation circuit 254, respectively, and the horizontal lines in each frame. It is initialized at the start point of the direction, and holds the maximum value and the minimum value of the Y signal of one horizontal line of the signal S7 in each frame.

These line maximum value hold circuits 244
And the line minimum value hold circuit 245 holds the maximum and minimum values of the Y signal held by the subtracter 246.
Is input to the peak hold circuits 247, 248, and 249, and the (maximum value-minimum value) signal, that is, the signal S10 representing contrast is calculated.

A gate signal for L frame generation is input from the frame generation circuit 254 to the peak hold circuit 247, and the peak hold circuit 247 is operated at the upper left LR1 which is the head of the L frame.
Is initialized, the signal S10 in each frame is peak-held, the peak-hold result is transferred to the buffer 250 by IR1, and the Max-Min evaluation value is generated.

Similarly, the peak hold circuit 248 receives a gate signal for C frame generation from the frame generation circuit 254,
The peak hold circuit 248 is initialized by CR1 at the top left of the C frame, the signal S10 in each frame is peak-held, the peak hold result is transferred to IR1, the buffer 251, and the Max-Min value is generated. To do.

Further, similarly, a gate signal for R frame generation is input from the frame generation circuit 254 to the peak hold circuit 249, and the peak hold circuit 249 is initialized by the upper left RR1 which is the head of the R frame. Signal S10 in the frame
Is peak-held, the peak-hold result is transferred to the buffer 252 by IR1, and the Max-Min evaluation value is generated.

At the time of IR1 when the scanning of the entire area for focus detection consisting of the L frame, the C frame, and the R frame is completed, the buffers 222, 223, 224, 228, 229, and 23 respectively.
0,238,239,240,241,242,24
At the same time that the data in each frame is transferred to 3,250, 251, 252, at the same time, an interrupt signal is sent from the frame generation circuit 254 to the microcomputer 114 to transfer the data transferred in each buffer to the microcomputer 114. And transfer processing.

That is, the microcomputer 114 receives the interrupt signal and, through the microcomputer interface 253, the buffers 222, 223, 224, 228, 229, 2
30,238,239,240,241,242,24
Each data in 3,250,251,252 is converted to the next L
The scanning in the frame, the C frame, and the R frame is completed until the next data is transferred to each buffer, and the data is read and transferred to the lens microcomputer 116 in synchronization with the vertical sync signal as described later.

The lens microcomputer 116 calculates these focus evaluation values, detects the focus state, calculates the focus motor drive speed and drive direction, and controls the focus motor to drive the focusing lens. .

Here, the timing of fetching various kinds of information in the AF signal processing circuit 113 will be described using the diagram showing the layout of each area for focus detection in the screen of FIG. The outer frame is an effective image pickup screen output from the image pickup devices 106, 107, and 108.

The inner three-divided frame is a focus detection gate frame, and the left L frame, the central C frame, and the right R frame are each L frame generation gate signals output from the frame generation circuit 254. C
It is formed according to the frame generation gate signal and the R frame generation gate signal.

Then, at the start positions of these L, C, and R frames, reset signals are output for each of the L, C, and R frames, and initialization (reset) signals LR1, CR1, and RR1 are output.
Are generated, and the integration circuits 232 to 237 and the peak hold circuits 219 to 221, 225 to 227, 247 to 249 are generated.
Etc. are reset.

A data transfer signal IR1 is generated at the end of scanning the focus detection area consisting of L, C, and R frames, and the integrated value of each integrator circuit and the peak hold value of each peak hold circuit are transferred to each buffer. .

Scanning of even fields is indicated by solid lines and scanning of odd fields is indicated by dotted lines. In both even and odd fields, the even lines select TE-LPF output and the odd lines select FE-LPF output.

Next, the TE / FE peak evaluation value in each frame, T
The following describes how the microcomputer performs the automatic focus adjustment operation using the E line peak integral evaluation value, the FE line peak integral evaluation value, the Y signal peak evaluation value, and the Max-Min evaluation value. Incidentally, these evaluation values are transmitted to the lens microcomputer 116 in the lens unit, and the actual control is performed by the lens microcomputer 116.

Here, the characteristics and uses of each evaluation value will be described.

The TE / FE peak evaluation value is an evaluation value representing the degree of focus, and is a peak hold value, so it is relatively independent of the subject and less affected by camera shake and the like, and is optimal for determination of the degree of focus and restart. .

The TE line peak integrated evaluation value and the FE line peak integrated evaluation value also represent the degree of focus, but they are stable evaluation values with little noise due to the integration effect, and are therefore optimal for direction determination.

Further, both the peak evaluation value and the line peak integral evaluation value are optimal near the in-focus state because the high frequency component of TE is extracted, and conversely, the FE is optimal during large blur far from the in-focus state. . Therefore, add these signals,
Alternatively, by selectively switching and using according to the level of TE, it is possible to perform AF with a wide dynamic range from large blurring to near the focal point.

The Y signal peak evaluation value and the Max-Min
Since the evaluation value does not depend much on the degree of focus and depends on the subject, it is ideal for grasping changes in the subject, movements, etc. in order to make sure focus determination, restart determination, and direction determination. is there. The focus evaluation value is also used for normalization to remove the influence of the change in brightness.

That is, the Y signal peak evaluation value is used to determine whether the object is a high-luminance object or a low-illuminance object, the Max-Min evaluation value is used to determine the contrast, and the TE / FE peak evaluation value and the TE line peak integration evaluation value are used. , By predicting and correcting the peak size of the FE line peak integrated evaluation value, optimum AF control can be performed.

These evaluation values are transferred from the camera body 128 to the lens unit 127, and the lens unit 12
It is supplied to the lens microcomputer 116 in 7 and the automatic focus adjustment operation is performed.

The algorithm of the automatic focus adjustment operation performed by the AF program 117 when the zoom operation is not performed in the lens microcomputer 116 in the lens unit 127 will be described with reference to FIG.

When the processing is started, the AF operation is first activated in the processing of step 1, then the processing proceeds to step 2, and the level of the TE or FE peak is compared with a predetermined threshold value to make a large blur. The speed control is performed by determining whether the focus is near the focus or how far from the focus.

At this time, when the TE level is low and it is expected to be at the foot of a mountain, that is, a large blur, the FE line peak integral evaluation value is mainly used to control the direction for focusing. When the lens is climbed and controlled, and the level of TE rises to a certain extent when reaching the top of the mountain, T
The focusing lens is climbed and controlled using the E-line peak integral evaluation value so that the in-focus point can be detected with high accuracy.

Next, when it comes near the in-focus point, step
Going to the process of 3, the peak of the mountain is judged by the absolute value of the TE or FE peak evaluation value or the amount of change of the TE line peak integral evaluation value, and the highest evaluation level is obtained at the top of the mountain, that is, the focal point. If it is determined to be a point, the focus lens is stopped in step 4, and the process of step 5 enters the restart standby.

In the restart waiting, when it is detected that the level of the TE or FE peak evaluation value is lower than the peak value when the in-focus point is detected by a predetermined level or more, the process is restarted in step 6.

By repeating the above processing, the AF operation can always be performed. In the loop of this automatic focus adjustment operation, the degree of speed control using the TE / FE peak, the absolute level of the mountain peak judgment, the amount of change in the TE line peak integral evaluation value, the Y peak evaluation value, M
The size of the mountain is predicted from the subject determination using the ax-Min evaluation value, and the determination is performed based on this.

Next, the relationship between the movements of the variable power lens 102 and the focus compensating lens 105 when performing the variable power operation, and how to refer to the AF evaluation value signal during the variable power operation from wide to tele will be described. .

In the lens system constructed as shown in FIG. 1, since the focus lens 105 has both the competition function and the focus adjustment function, the image pickup elements 106, 107 and 108 are focused even if the focal lengths are the same. The position of the focus lens 105 depends on the subject distance.

When the subject distance is changed at each focal length, the position of the focus lens 105 for focusing on the image pickup surface of each image pickup element is continuously plotted.
As shown in FIG. In the figure, the horizontal axis represents the zoom lens position (focal length), and the vertical axis represents the focus lens position. The locus information is the content of the lens cam data 120 in the lens microcomputer 116.

During the zoom operation, depending on the object distance, FIG.
By selecting the locus indicated by and moving the focus lens 105 so as to trace the locus, a zoom operation without blur becomes possible.

In the front-lens focus type lens system, an independent compensator lens is provided for the variable power lens, and the variable power lens and the compensator lens are connected by a mechanical cam ring.

Therefore, for example, if a knob for manual zooming is provided on this cam ring and the focal length is manually changed, no matter how fast the knob is moved, the cam ring will follow this and rotate to change the magnification. Since the lens and the compensator lens move along the cam groove of the cam ring, if the focus lens is in focus, the above operation does not cause blurring.

However, in the control of the inner focus type lens system having the above-mentioned characteristics, when the zoom operation is performed while keeping the focus,
The locus information of FIG. 5 is stored in the lens microcomputer 116 as the lens cam data 120, the locus information is read from the lens cam data 120 according to the position or the moving speed of the variable magnification lens 102, and the focus is performed based on the information. It is necessary to move the lens 105.

FIG. 6 is a drawing for explaining an example of the trajectory following method that has been devised. In the figure, Z0,
Z1, Z2, ..., Z6 represent the zoom lens positions,
a0, a1, a2, ..., a6 and b0, b1, b2
, ..., b6 are representative loci stored as the lens cam data 120 in the lens microcomputer 116.

Further, p0, p1, p2, ..., P6 are loci calculated based on the above two loci. The formula for calculating this locus is shown below.

P (n + 1) = | p (n) -a (n) | / | b (n) -a (n) | * | b (n + 1) -a (n + 1) | + a (n + 1) (1) According to this equation (1), for example, in FIG. 6, when the focus lens is at p0, the ratio at which p0 internally divides the line segment b0-a0 is obtained, and according to this ratio, The point that internally divides the line segment b1 -a1 is p1.

From the position difference between p1 and p0 and the time required for the variable power lens to move from Z0 to Z1, the moving speed of the focus lens for keeping the focus can be known.

Next, a case will be described in which there is no limitation that the stop position of the variable power lens 102 must be on the boundary that owns the representative locus data stored in advance.

FIG. 7 is a diagram for explaining an interpolation method in the position of the variable power lens (horizontal axis direction), in which a part of FIG. 6 is extracted and the variable power lens is arbitrary.

In FIG. 6, the vertical axis represents the focus lens position, and the horizontal axis represents the variable power lens position. The representative locus position (the focus lens relative to the variable power lens position stored in the lens cam data 120 by the lens microcomputer 116). Position) to the zoom lens positions Z0, Z1, ..., Zk-1, Z
For k, ..., Zn, the focus lens positions at that time are classified by subject distances as a0, a1, ..., ak-1, ak, ..., an b0, b1 ,. It is represented by bk-1, bk, ..., Bn.

Now, when the zoom lens position is at Zx not on the zoom boundary and the focus lens position is Px,
When ax and bx are calculated, ax = ak- (Zk-Zx) * (ak-ak-1) / (Zk-Zk-1) ... (2) bx = bk- (Zk-Zx) * (bk-bk -1) / (Zk-Zk-1) (3)

That is, the current zoom lens position and two zoom boundary positions sandwiching it (for example, Zk and Zk-1 in FIG. 7).
In accordance with the internal division ratio obtained from, the four representative locus data stored (ak, ak-1, bk, bk-1 in FIG. 7) with the same subject distance are internally divided by the internal division ratio. By doing so, ax and bx can be obtained.

Then, according to the internal division ratio obtained from ax, Px, bx, the four representative data stored (in FIG. 7, ak, a
Of k-1, bk, bk-1), pk, pk-1 can be obtained by internally dividing those having the same focal length with the internal division ratio as shown in equation (1).

Then, at the time of zooming from wide to tele, the focus difference is kept from the position difference between the follow-up focus position pk and the current focus position px and the time required for the zoom lens to move from Zx to Zk. You can see the moving speed of the focus lens.

When zooming from tele to wide, focusing is performed based on the positional difference between the follow-up focus position pk-1 and the current focus position Px and the time required for the zoom lens to move from Zx to Zk-1. You can see the moving speed of the focus lens to keep it. A trajectory following method as described above has been devised.

By the way, when the AF switch 131 is on, it is necessary to follow the locus while maintaining the focus.
When the zoom lens moves from tele to wide,
As is clear from FIG. 5, since the scattered trajectories are in the direction of convergence, the in-focus can be maintained even by the above-mentioned trajectory following method.

However, in the wide-to-tele direction,
Since it is not known which trajectory the focus lens at the convergence point should follow, the similar trajectory following method cannot maintain the focus.

FIG. 8 is a diagram for explaining an example of a trajectory following method devised for the above problem. In both of the figures (a) and (b), the horizontal axis represents the position of the variable power lens, and the vertical axis (a) represents the level of the high frequency component (sharpness signal) of the video signal which is the AF evaluation signal. FIG. 3B shows the position of the focus lens.

In the figure, it is assumed that the focus cam locus when performing a zoom operation on a certain subject is 604.

Here, the focusing cam locus following speed on the wide side from the zoom position 606 (Z14) is positive (moved in the direction close to the focus lens), and the focusing cam locus following speed moving on the tele side from 606 is infinite. Negative.

Then, when the focus lens follows the cam locus 604 while maintaining the focus, the magnitude of the sharpness signal becomes 601. In general, it is known that the sharpness signal level has a substantially constant value in zooming while maintaining focus.

In FIG. 16B, the focus lens moving speed tracing the focusing cam locus 604 during zoom operation is Vf0. When the actual moving speed of the focus lens is Vf and the zoom operation is performed while changing the size of Vf0 tracing the cam locus 604, the locus becomes 6
It becomes a locus of zigzag like 05.

At this time, the sharpness signal level changes so as to produce peaks and valleys as indicated by 602. Locus 60 here
At the position where 4 and 605 intersect, the size of 603 becomes maximum (even point of Z0, Z1, ... Z16), and at the odd point of Z0, Z1, ... Z16 where the moving direction vector of 605 switches. The level of 603 is the minimum.

602 is the minimum value of 603, but conversely 6
02 level TH1 is set, and the size of 603 is TH1.
When the moving direction vector of the locus 605 is switched every time when it becomes equal to, the moving direction of the focus lens after switching is
It can be set in a direction approaching the focus locus 604.

That is, the sharpness signal levels 601 and 602
By controlling the moving direction and speed of the focus lens so as to reduce the blur every time the image is blurred by the difference of (TH1), the zoom operation with the blur amount suppressed can be performed.

By using the above-described method, in the zoom operation from the wide to the tele as shown in FIG. 3 where the cam locus diverges from the convergence, even if the focusing speed Vf0 is not known, FIG. For the following speed (calculated using p (n + 1) obtained from the equation (1)), the switching operation is repeated as indicated by 605 while controlling the focus lens moving speed Vf (sharpness signal level The sharpness signal level does not drop below 602 (TH1), that is, no blurring of a certain amount or more occurs.
The focus cam locus can be selected.

Here, the moving speed Vf of the focus lens
Is Vf + for the correction speed in the positive direction and Vf- for the correction speed in the negative direction.
Vf = Vf0 + Vf + (4) Vf0 + Vf- (5), the correction velocities Vf + and Vf- at this time are adjusted so that the deviation does not occur when the following trajectory is selected by the zoom operation method. , (4), the internal angle of the two direction vectors of Vf obtained by the equation (5) is 2 by the direction vector of Vf0.
It is decided to be divided equally.

By changing the magnitude of the correction amount by the correction speed according to the subject, the focal length, and the depth of field, the increase / decrease cycle of the sharpness signal is changed to improve the selection accuracy of the tracking locus. Another method is also proposed.

According to the first aspect, the correction lens corresponds to the focus lens 105 of the embodiment, the extracting means corresponds to the image pickup means 106 to 108, the memory means corresponds to the lens cam data 120, and the control is performed. The means corresponds to the lens microcomputer 116 including the computer zoom 119 in the lens unit, and data communication from the microcomputer 114 in the camera body to the lens microcomputer 116 in the lens unit outputs the output of the extracting means from the camera side to the lens unit. It is equivalent to the means to deliver to the side.

With regard to claim 2, the plurality of filter means are the TE-LPF 21 in the AF signal processing circuit 113.
4, which corresponds to FE-LPF215 and HPF217.

In the third aspect, the means for detecting the peak hold output obtained by peak-holding the brightness component of the image pickup signal corresponding to the focus detection area corresponds to the peak hold circuits 219, 220, 221.

In the fourth aspect, the means for detecting the contrast component of the image pickup signal corresponding to the focus detection area corresponds to the line maximum value hold circuit 244, the line minimum value hold circuit 245, and the subtractor 246.

Further, in claim 5, the peak hold means for detecting the contrast component corresponds to the peak hold circuits 247, 248, 249.

Further, in claim 6, the correction lens corresponds to the focus lens 105 of the embodiment, the extraction means corresponds to the AF signal processing circuit 113 in the camera signal processing circuit 112, and the image pickup means corresponds to the image pickup elements 106 to 108. The switch for operating the zooming operation corresponds to the zooming switch 130, the memory means corresponds to the lens cam data 120, and the control means corresponds to the computer zoom 119 in the lens unit.
The data communication from the microcomputer 114 in the camera body to the lens microcomputer 116 in the lens unit corresponds to the means for delivering the output of the extracting means from the camera side to the lens unit side.

Further, in claim 7, the memory means corresponds to the lens cam data 120, the control means corresponds to the lens microcomputer 116 including the computer zoom 119 in the lens unit, and the microcomputer 114 in the camera body to the lens unit. The data communication to the lens microcomputer 116 corresponds to a means for delivering the output of the extracting means from the camera side to the lens unit side.

Further, in claim 8, the extracting means corresponds to the AF signal processing circuit 113 in the camera signal processing circuit 112, and the instructing means for instructing the zooming operation is the zoom switch 13.
0, and the communication means is the microcomputer 114 in the camera body.
To data communication from the lens to the lens microcomputer 116 in the lens unit.

[0135]

As described above, according to the first aspect of the present invention, the focus evaluation value is transferred from the camera body side to the lens unit side, and is stored in the memory means in the lens unit. To determine the driving speed and direction of the correction lens based on the focus evaluation value and the position information of the correction lens for correcting the focal position displaced along with the movement of the zoom lens during the zooming operation. This makes it possible to determine the optimum responsiveness for each lens regardless of the type of lens attached, regardless of the front lens or inner focus type, and to stably focus on the intended main subject under all subjects and shooting conditions. In addition to this, it is possible to realize an interchangeable lens system that can perform zooming without blur.

Further, according to the inventions of claims 2 to 5, a specific frequency component, a peak value of a luminance component, and a contrast component in the image pickup signal are used as the evaluation value of the focus state, respectively, and the focus detection with higher precision is performed. It is possible to perform, and by using a plurality of focus state evaluation values, it is possible to correspond to various characteristics and functions of the lens side,
A system with high versatility can be realized.

According to the sixth aspect of the present invention, the control means for the zooming operation is provided in the lens unit, and the state of the switch for zooming operation is passed from the camera side to the lens unit so that the zooming operation and the zooming operation are performed on the lens unit side. By correcting the focal plane, lens units of any lens type can be connected regardless of the front lens or inner focus, and at the same time the magnification control means for all lens units is inside the lens unit. Without changing the operability, the camera body can be operated for zooming, and the interchangeable lens system can be realized without degrading the operability.

According to the seventh aspect of the present invention, the focus evaluation value signal transferred from the camera side and the zooming lens stored in the memory means in the lens unit are displaced along with the movement of the zooming lens during the zooming operation. The driving speed and the driving direction of the focus lens are determined in the lens unit by using the position information of the focus lens for correcting the focal position, so that the lens unit has no burden on the camera side. It is possible to realize a lens unit that can be driven in optimal conditions by fully exerting its characteristics and functions.

According to the eighth aspect of the invention, in the lens unit, the focus evaluation value and the magnification change operation are performed from the camera body side so that the displacement of the focal plane due to the AF operation and the magnification change operation are simultaneously corrected. Since the instruction information of is sent to the control means in the lens unit, the characteristics and functions of the lens unit can be fully utilized without burdening the camera side, and a lens unit that can be driven in an optimal state can be obtained. Can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an automatic focus adjustment device of the present invention.

FIG. 2 is a block diagram showing an internal configuration of an AF signal processing circuit on the camera body side in the automatic focusing apparatus shown in FIG.

FIG. 3 is a diagram for explaining an extraction operation and extraction timing of various focus evaluation values according to the present invention.

FIG. 4 is a flow chart for explaining an AF operation in the embodiment of the present invention.

FIG. 5 is a diagram showing a movement locus (lens cam data) of the focus lens for correcting the position of the focal plane, which is displaced due to the variable power operation of the variable power lens, to maintain the in-focus state.

FIG. 6 is a diagram for explaining a calculation for incorporating an unstored cam locus from information on a plurality of cam loci stored in lens cam data.

FIG. 7 is a diagram for explaining a calculation for incorporating an unstored cam locus from information on a plurality of cam loci stored in lens cam data.

FIG. 8 is a diagram for explaining an algorithm for causing a focus lens to follow a cam locus.

FIG. 9 is a block diagram showing a typical configuration of a conventional automatic focus adjustment device.

[Explanation of symbols]

 105 Focus Lens 106 Image Sensor 107 Image Sensor 108 Image Sensor 112 Camera Signal Processing Circuit 113 AF Signal Processing Circuit 114 (Camera) Main Unit Microcomputer 116 Lens Microcomputer 117 AF Control Circuit 118 Motor Control Circuit 119 Computer Zoom Program 120 Lens Cam Data 125 Focus Motor 126 Motor driver 130 Zoom switch

Claims (8)

[Claims] 1. A variable power lens that performs a variable power operation, a correction lens that corrects a focus to maintain a focused state in the variable power operation, and a memory that stores the positional relationship between the variable power lens and the correction lens. Means, an image pickup means for converting an image formed through the variable power lens and the correction lens into an electric signal, and one or more focus detection areas in the screen from among the image pickup signals output from the image pickup means. An extraction means for extracting a focus signal corresponding to the inside, and a control means for controlling the variable magnification lens and the correction lens based on both the output of the memory means and the extraction means to perform a variable magnification operation, An interchangeable lens having the control means and the memory means in a lens unit including the variable power lens means and the correction lens means, and delivering the output of the extraction means to the lens unit. Camera system. 2. The extracting means according to claim 1, wherein the extracting means includes a plurality of filter means for extracting a signal of a specific frequency component from an image pickup signal corresponding to the focus detection area in the image pickup signal as the focus signal. An interchangeable lens type camera system characterized by being provided. 3. The exchange according to claim 2, wherein the extracting means further comprises means for detecting a peak hold output obtained by peak-holding a luminance component of an image pickup signal corresponding to the focus detection area. Lens type camera system. 4. The interchangeable lens type camera system according to claim 2, wherein the extracting means further comprises means for detecting a contrast component of an image pickup signal corresponding to the focus detection area. 5. The extraction means according to claim 4, further comprising peak holding means for detecting the contrast component by peak-holding a difference between the maximum value and the minimum value of the brightness component in the focus detection area. An interchangeable lens type camera system characterized in that 6. A variable power lens that performs a variable power operation, a correction lens that corrects a focus for maintaining a focused state in the variable power operation, and a memory that stores the positional relationship between the variable power lens and the correction lens. Means, an image pickup means for converting an image formed through the variable power lens and the correction lens into an electric signal, a switch for operating a variable power operation, and an image signal within the screen from among the image pickup signals output from the image pickup means. 1
Extracting means for extracting a focus signal in one or a plurality of focus detection areas, and controlling the zoom lens and the correction lens based on both the output of the memory means and the extracting means when the switch is operated. Having a control means for performing a magnification change operation, having the control means and the memory means in a lens unit including the magnification change lens means and the correction lens means, and delivering the output of the extraction means and the state of the switch to the lens unit. An interchangeable lens type camera system. 7. A lens unit attachable to and detachable from a camera body, which comprises a variable power lens for performing a variable power operation, a focus lens for performing focus adjustment, and a focus state for maintaining the in-focus state during the variable power operation. Memory means for storing the position information of the focus lens, receiving means for receiving an evaluation value signal of a focus state and instruction information of a zooming operation transmitted from the camera body side, and the receiving means When the instruction information for the magnification operation is received, the control means for controlling the magnification lens and the correction lens based on both the storage information of the memory means and the evaluation value signal of the focus state to perform the magnification operation. A lens unit characterized by having and. 8. A camera in which a lens unit is detachable, and an extracting means for extracting a focus signal from an image pickup signal corresponding to one or a plurality of focus detection areas in a screen, and a zooming operation. In order to drive the focus lens to the focal point on the lens unit side by providing an instruction means, an operation state of the instruction means, and a communication means for transmitting the output signal of the extraction means to the microcomputer in the lens unit. A camera capable of calculating a driving direction and a driving speed of the camera.