JPH095609A - Camera system - Google Patents

Abstract

PURPOSE: To provide an automatic focusing device which can be stably focused on an aimed main subject on a photographing condition even when a lens and a camera having different versions are combined. CONSTITUTION: This system is provided with an AF signal processing circuit 113 including a filter for extracting a focusing signal out of image pickup signals corresponding to the inside of one or plural focus detection areas in an image plane, a lens microcomputer 116 deciding a driving direction and driving speed for driving the focusing lens to a focusing point based on the increase/decrease of the level of an output signal from the circuit 113, and a focusing motor 125 driving the focusing lens based on the decision of the microcomputer 116. The circuit 11 3 is arranged on a camera side and the microcomputer 116 and the focusing motor are arranged in a lens unit, then output from the circuit 113 and information expressing the version thereof are transferred from the camera side to the lens unit side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera system suitable for use in a video camera or the like having an interchangeable lens unit.

[0002]

2. Description of the Related Art Conventionally, as an automatic focusing device used in video equipment such as a video camera, a high frequency component is extracted from an image pickup signal obtained from an image pickup device such as a CCD, and this high frequency component is maximized. A so-called hill-climbing method is known in which the photographic lens is driven so as to adjust the focus.

Such an automatic focus adjustment system does not require a special optical member for focus adjustment for detecting emission / reception of infrared rays or an image shift amount which changes according to a focus state, and it is possible to use a long distance. It has the advantage of being able to focus accurately regardless of the distance even in the vicinity.

An example in which this type of automatic focusing system is used in a video camera in which the lens can be replaced will be described with reference to FIG.

In the figure, reference numeral 1 denotes a focus lens, which is moved by a lens driving motor 11 in the optical axis direction for focusing. The light passing through this lens is
An image is formed on the image pickup surface of the image pickup device 2, photoelectrically converted into an electric signal, and output as a video signal.

This video signal is sampled and held by the CDS / AGC 3 and then amplified to a predetermined level.
It is converted into digital video data by the converter 4, is input to a process circuit of a camera (not shown), and is converted into a standard television signal, and a band pass filter (hereinafter referred to as B
PF) 5.

The BPF 5 extracts a high frequency component from the video signal, the gate circuit 6 extracts only the signal corresponding to the part set in the focus detection area in the screen, and the peak hold circuit 7 extracts an integer of the vertical synchronizing signal. The peak hold is performed at an interval synchronized with the double, and an AF evaluation value is generated.

This AF evaluation value is taken into the AF microcomputer 8 of the camera body, and the focus motor drive speed according to the degree of focus within the AF microcomputer 8 of the camera body and the motor drive direction that increases the AF evaluation value are set. Then, the drive speed and drive direction of the focus motor are transmitted to the lens microcomputer 9 in the lens unit.

The lens microcomputer 9 operates the focus lens 1 by the focus motor 11 via the motor driver 10 as instructed by the AF microcomputer 8 of the camera body.
Is adjusted in the optical axis direction to adjust the focus.

[0010]

However, in the above-mentioned conventional example, since the lenses can be exchanged, the control of the automatic focus adjustment is provided on the camera body side, so that the automatic focus adjustment is optimized for a specific lens. Once the responsiveness is determined, it may not be optimal for other lenses, and it has been difficult to obtain optimal performance for all removable lenses.

Therefore, an object of the present invention is to solve the above-mentioned problems and provide an automatic focus adjusting device that stably focuses on a target main subject regardless of the type of lens attached and under all subjects and shooting conditions. Especially.

[0012]

In order to solve the above-mentioned problems, according to the invention described in claim 1 of the present application, the image pickup signal corresponding to one or more focus detection areas in the screen is selected. Extraction means for extracting the focus signal, control means for determining the drive direction and drive speed for driving the focus lens of the optical system to the in-focus point based on the increase or decrease in the level of the output signal of the extraction means, and based on the control means Drive means for driving the focus lens, the extraction means is arranged on the camera side, the control means and the drive means are arranged in a lens unit, and the output of the extraction means and the type of the focus signal are represented. A camera system is configured to drive the focus lens by passing information from the camera side to the lens unit side.

According to the second aspect of the present invention, in the first aspect, the control means is configured to change the control method of the focus adjusting operation according to the type information of the focus signal.

According to the invention of claim 3 of the present application, in claim 2, the extracting means has a filter for extracting a specific frequency component from the image pickup signal, and the control means controls the focus signal of the focus signal. It is configured to change the speed of the focus adjustment operation or the threshold value for changing the operation according to the type information.

According to a fourth aspect of the present invention, in the first aspect, the focus signal and the type to be passed to the lens unit according to the focus adjustment control status of the lens unit on the camera body side. The configuration is provided with means for changing information.

According to the invention of claim 5 of the present application, the lens unit is attachable to and detachable from the camera body having the focus detecting means, and the focus signal transmitted from the camera side and the type information of the focus signal are transmitted. The receiving means for receiving and the focus state is determined based on the focus signal received by the receiving means, the focus lens drive speed and the drive direction are calculated and determined, and according to the type information of the focus signal. Control means for changing the control method of the focus adjustment operation,
A lens unit including a driving unit that drives the focus lens based on a calculation result of the control unit.

According to the invention of claim 6 of the present application, it is a lens unit which can be attached to and detached from the camera body, and which has an adjusting means for adjusting an image pickup state, an evaluation value of the image pickup state transmitted from the camera side, and Receiving means for receiving the type information of the evaluation value and an image pickup state based on the evaluation value received by the receiving means, and calculating control values such as driving speed and driving direction of the adjusting means. The lens unit is characterized by including control means for determining and changing the control value according to type information of the evaluation value, and drive means for driving the adjusting means based on the calculation result of the control means. .

According to a seventh aspect of the present invention, there is provided a camera having a detachable lens unit, a detecting means for detecting an image pickup state, and an evaluation value of the image pickup state detected by the detecting means. And a transmitting means for transmitting the type information of the evaluation value to the lens unit, the lens unit side adjusts the imaging state based on the evaluation value, and the adjusting method according to the type information. It features a camera that can change the.

[0019]

According to the first aspect of the invention, the signal used as the focus evaluation value corresponding to the inside of the focus detection area extracted by the extracting means is transferred to the lens unit side to be stored in the lens unit. The control unit determines the drive speed and drive direction of the focus lens of the optical system, and can change the focus control method according to the type information.

According to the invention described in claim 2, according to claim 1,
In the above, since the control method of the focus adjustment operation is changed according to the type information of the focus signal, the drive speed and drive direction of the focus lens of the optical system are determined by the control means in the lens unit, and the type information Accordingly, the focus control algorithm is changed and optimized.

According to the invention of claim 3, claim 2
In addition, the filter characteristic is further determined according to the type information of the focus signal, and the speed of the focus adjustment operation or the threshold value for changing the operation is changed.

According to the invention of claim 4, claim 1
In accordance with the focus adjustment control situation of the lens unit, the type of the lens unit is discriminated, and the focus signal and the type information of the focus signal are changed so as to match the type.

According to the fifth aspect of the present invention, the focus state is determined on the lens unit side according to the focus signal transmitted from the camera side and the type information of the focus signal, and the focus lens drive speed and drive direction. Is calculated, and the control method of the focus adjustment operation is changed according to the type information.

According to the invention described in claim 6, on the side of the lens unit, the imaging state is discriminated and adjusted according to the evaluation value of the imaging state and the type information of the evaluation value transmitted from the camera side. The control values such as the driving speed and the driving direction of the means are calculated, and the control values are changed according to the type information of the evaluation value.

According to the invention described in claim 7, the image pickup state is detected on the camera side, and the evaluation value of the image pickup state and the type information of the evaluation value are transmitted to the lens unit side,
The image pickup state is adjusted on the side of the lens unit, and the adjustment method can be changed on the side of the lens unit according to the type information.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

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 and 108 are photoelectrically converted into amplifiers 109 and 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 device, 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
Indicates 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 lens microcomputer 116.
Send to.

In the lens microcomputer 116, the AF program 117 causes the AF switch 1 from the main body microcomputer 114.
When the state of No. 31 and the AF evaluation value are received, and the AF switch 131 is on, the motor control program 118 is operated based on this AF evaluation value, the focus motor driver 126 drives the focus motor 125, and the focus lens 105 is driven. Focusing is performed by moving in the optical axis direction.

Further, the motor driver 122 is controlled according to the operation state of the zoom switch 130 to control the zoom motor 12
The zoom operation is performed by driving 1 to 9 degrees and driving the zoom lens 102.

On the other hand, when the lens unit is of the inner focus type, the focal plane is changed by driving the zoom lens 102, so that the focus lens 105 has a predetermined characteristic as the zoom lens is driven. Therefore, the operation of driving and preventing the occurrence of blurring due to the displacement of the focal plane is performed in parallel.

The lens cam data 120 in the lens microcomputer 116 is a ROM in which the focus position of the focus lens with respect to the position of the zoom lens is stored for each object distance.
With the computer zoom control program 119,
The position of the zoom lens and the position of the focus lens are respectively detected by the drive amount of the motor or the encoder, and the focusing locus to be followed by the focus lens during the zoom operation is specified and read out from the ROM 120 to perform the zoom operation of the focus lens. Calculate the correction speed and direction associated with.

The information on the correction speed and the direction is added to the AF blur information output from the AF circuit 117 by the motor control program 118 to calculate the total focus lens drive speed and drive direction, and the motor driver. Is supplied to 126.

The aperture value of the iris 103 is detected by the encoder 129, 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 the even lines and the signal S7 is supplied for the 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, the C frame and the 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 gate signal L for outputting the L frame output from the frame generation circuit 254 and a Line E / O signal (microcomputer) 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 output from the frame generation circuit 254 and the Line E / O signal are input to the peak hold circuit 226, and the peak hold is performed by 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 receives a signal S9 and a 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 with 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 lines 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 with 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.

Further, 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 to the peak hold circuit 247 from the frame generation circuit 254, and the peak hold circuit 247 is 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.

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 three inner frames are focus detection gate frames, and the left L frame, the center C frame, and the right R frame are 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, a reset signal is output for each of the L, C, and R frames at the start positions of these 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 integrating circuit and the peak hold value of each peak hold circuit are transferred to each buffer. .

Scanning of even fields is indicated by a solid line and scanning of odd fields is indicated by a dotted line. In both even and odd fields, the even line selects the TE-LPF output and the odd line selects the 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.

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 most suitable for determination of the degree of focus and restart. .

The TE line peak integral evaluation value and the FE line peak integral evaluation value also represent the degree of focus. However, 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 integration evaluation value are optimal near the in-focus state because the high frequency components of TE are 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 determined. , By predicting and correcting the peak size of the FE line peak integrated evaluation value, optimum AF control can be performed.

These evaluation values, and version information indicating the type and content of each evaluation value are transferred from the camera body 128 to the lens unit 127 and supplied to the lens microcomputer 116 in the lens unit 127 for automatic focus adjustment operation. Done.

Here, the version information of the evaluation value will be described. This version information is the function of the camera body side.
The optimum signal can be selected as the AF evaluation value according to the performance. For example, the image pickup devices 106, 107,
When the sensitivity and the number of pixels of 108 have improved dramatically from the past, and the frequency characteristics and dynamic range of the video signal have improved,
It is expected that the frequency component of the signal indicating the focus degree shifts to a higher frequency side, and the amount of change in the evaluation value when defocusing by the circle of least confusion becomes larger.

Therefore, TE-LPF 214 and FE-LPF
It is necessary to change the filter characteristic of 215 from the conventional setting, and the AF evaluation value obtained at this time is an evaluation value having contents different from the conventional evaluation value.

For the version of this evaluation value, the former is Ver.
FIG. 4A shows the specific contents of the version and the evaluation value that are communicated from the camera body to the lens unit, with the latter being Ver2.

In this embodiment, the type and number of evaluation values do not change due to differences in version for simplification, but regarding the number of words to be transmitted and the type and content of evaluation value for each word, the lens on the receiving side Normally, as long as it supports units,
There is no regulation on communication compatibility.

As described above, since the characteristics of the evaluation value differ depending on the version, it is possible to realize higher performance AF by making the AF control algorithm correspond to the characteristics.

The AF evaluation value Ver shown in FIG.
FIG. 4B shows that the AF control corresponding to 1 and Ver2 is respectively set to the AF control versions Ver1 and Ver2.
The communication contents returned from the lens unit to the camera body.

The algorithm of the automatic focus adjustment operation in the lens microcomputer in the lens unit will be described with reference to the flowchart of FIG.

In this embodiment, the lens microcomputer corresponds to the Ver2 AF control, and the AF evaluation value sent by the camera body is Ve.
It is assumed that either r1 or Ver2 will do.

The communication between the lens microcomputer 116 and the main body microcomputer 114 is executed by a process different from that shown in FIG. 5, and its timing will be described later.

The program is started in S1 and the version of the evaluation value is determined in S2.
If 2, the mountain climbing control 2 is executed in S4. Here, hill climbing control is speed control (TE or F
The lower the E peak level is, the more likely it is to be at the foot of the mountain, so drive at high speed), and the TE line peak integrated evaluation value at the top of the mountain and the FE line peak integrated evaluation value at the foot of the mountain are mainly used. Focus control is performed by controlling the direction of the focus.

As described above, assuming that the evaluation value of Ver2 corresponds to a video signal obtained from a high-resolution / high-sensitivity image sensor, the evaluation value of Ver2 is higher than that of Ver1 near the top of a mountain near the focal point. Blurring tends to be easier to recognize when the focus lens is moved by the same amount.

Therefore, in the processing of S3 and S4, the lens moving speed near the top of the mountain is set to be slower in S4 (S
3: speed α, S4: speed β = α / 2).

Next, in S5, the peak of the mountain is judged by the absolute value of the TE or FE peak evaluation value or the change amount of the TE line peak integration evaluation value, and the evaluation is stopped at the highest level point. Store in memory.

At S6, the same process as at S2 is performed. If the version of the evaluation value is Ver1, the process goes to the restart waiting 1 at S7, Ve.
If r2, the process shifts to the restart standby 2 of S8.

In the restart standby, it is detected whether or not the level of the TE or FE peak evaluation value is lower than the level stored in the memory in S5, and if it is detected that the level is lowered,
The process moves to S9 and restarts.

Here, the evaluation value of Ver2 has a higher resolution.
If it corresponds to a high-sensitivity image pickup signal, even if the same blurring occurs visually, the evaluation value level tends to be larger in Ver2, so the evaluation value variation threshold value for the restart determination is The restart activation standby 2 of S8 is set to be larger (for example, in the experiment, the process of S7 is set to restart with a change of 20% or more with respect to the storage level, and the process of S8 is set to 40 with respect to the storage level. It was set to restart with a change of more than%).

In the loop of this automatic focus adjustment operation, T
The degree of speed control using the E / FE peak, the absolute level of the mountain peak judgment, the amount of change in the TE line peak integrated evaluation value, etc. can be determined by subject judgment using the Y peak evaluation value or the Max-Min evaluation value. Predict the size of the mountain and make a decision based on this.

Up to this point, the lens unit version has been described as being Ver2, but in the case of Ver1, the processing of S1, S2, S5, S7 and S9 in FIG. 5 may be performed. In this case, the evaluation value passed from the camera body can correspond only to Ver1.

Next, the communication timing between the camera body and the lens will be described with reference to FIG. As described above, the AF evaluation value read by the main body microcomputer is transferred to the lens microcomputer immediately after the vertical sync signal in synchronization with the next vertical sync signal (V sync).

FIG. 6 is a view for explaining the method of adjusting the version of the communication between the camera body and the lens, and shows the processing flow performed in the body microcomputer 114 on the camera body side. Here, it is assumed that the camera body is a camera corresponding to the evaluation value Ver2 of FIG. 4A and the lens unit may be either the AF control version of FIG. 4B.

First, in S11, the program is started up, and in S12, the latest version of the main body microcomputer (here, Ver.
The setting for generating the AF evaluation value according to 2) is performed (in the case of the example described in FIG. 5, TE-LPF 214 and FE).
-The filter characteristic of the LPF 215 is set so that a higher frequency component can be extracted than before.

Next, in order to communicate with the lens microcomputer 116 at the communication timing of FIG. 7, the process waits until a vertical synchronizing signal arrives in S13, mutual communication is carried out in S14, and data is exchanged as shown in FIG.

In S15, it is determined whether the version of the evaluation value sent and the control version for which the lens microcomputer can perform AF control match.

If they match, the process goes to S18 to execute the normal control of the camera, and waits in S13 until the next vertical synchronizing signal comes.

If the versions do not match in S15, the setting for generating the AF evaluation value matched with the AF control version of the lens unit is performed in S16, and S17 is performed.
Change the evaluation value version with and return to S13.

Therefore, in the next communication, since the version with the lens microcomputer matches in S15, the processing from S18 can be performed.

In the correspondence relationship between the claims and the embodiments described above, in claims 1 and 2, the correction lens corresponds to the focus lens 105 of the embodiment, the extraction means is the image pickup means, and the image pickup element 106 to. 108, 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 11 in the camera body.
Data communication from 4 to the lens microcomputer 116 in the lens unit corresponds to a means for delivering the output of the extracting means from the camera side to the lens unit side.

Further, according to claim 3, the filter is AF
TE-LPF 214 and FE-L in the signal processing circuit 113
It corresponds to PF215 and HPF217.

Further, in claim 4, the means for changing the focus signal and the type information delivered to the lens unit corresponds to the main body microcomputer 114 on the camera side, and the processing thereof corresponds to the processing of the flow chart of FIG.

In claim 5, the receiving means corresponds to the lens microcomputer 116 which receives the evaluation value of the AF signal processing circuit 113 and its version information transmitted from the microcomputer 114 in the camera body to the lens microcomputer 116 in the lens unit. The control means corresponds to the AF processing program 117 and the motor control program 118 in the lens microcomputer 116, and the driving means is the focus motor 12
5, corresponding to the motor driver 126.

In the sixth aspect, the adjusting means corresponds to the focus lens 105, and the receiving means is the evaluation value of the AF signal processing circuit 113 transmitted from the microcomputer 114 in the camera body to the lens microcomputer 116 in the lens unit and Lens microcomputer 11 that receives the version information
6, the control means is an AF processing program 117 and a motor control program 1 in the lens microcomputer 116.
18, and the driving means corresponds to the focus motor 125 and the motor driver 126.

Further, in claim 7, the detection means is AF
Corresponding to the signal processing circuit 113, the transmitting means sends to the lens microcomputer 116 in the lens unit the AF signal processing circuit 11
It corresponds to the main body microcomputer 114 that transmits the evaluation value of 3 and its version information.

[0115]

As described above, according to the first to third aspects of the present invention, the focus signal and the type information of the focus signal are passed to the lens unit, and the automatic focus adjustment control is performed by the lens unit. By having it, it is possible to determine the optimum responsiveness etc. for each lens regardless of what kind of lens is attached, and to provide an automatic focus adjustment device that can stably focus on the main subject of interest under all subjects and shooting conditions. It will be possible.

In particular, by passing the type information of the focus signal, it is possible to add to the conventional focus signal or change the content or type of the signal, such as a focus signal newly required in accordance with technological progress such as high pixel CCD. It is possible to upgrade the version, and by optimizing AF control according to the version of the focus signal passed, it is highly expandable, does not become obsolete forever, and is stable to the target main subject under all shooting conditions and shooting conditions. It is possible to realize an automatic focus adjustment device for an image pickup device that can focus and has a replaceable lens.

According to the invention described in claim 4, the camera body always delivers the latest version of the focus signal that can be supported by the lens unit, so that the capability of the lens unit can be improved regardless of whether the lens unit is old or new. It is possible to realize an automatic focus adjustment device that maximizes the use.

According to the invention described in claim 5, the focus state is determined on the lens unit side according to the focus signal transmitted from the camera side and the type information of the focus signal, and the focus lens drive speed and drive Since the direction is calculated and the control method of the focus adjustment operation is changed according to the type information, it is possible to determine the optimum responsiveness etc. for each lens no matter what lens is attached,
It is possible to provide a lens unit automatic focus adjustment device capable of stably focusing on a target main subject under all subjects and shooting conditions.

In particular, by passing the type information of the focus signal, it is possible to add to the conventional focus signal or change the content or type of the signal, such as a focus signal newly required according to technological progress such as a high pixel CCD. It is possible to upgrade the version, and by optimizing AF control according to the version of the focus signal passed, it is highly expandable, does not become obsolete forever, and is stable to the target main subject under all shooting conditions and shooting conditions. The lens unit of the interchangeable lens type camera system that can focus can be realized.

According to the sixth aspect of the invention, the lens unit side determines the image pickup state according to the evaluation value of the image pickup state and the type information of the evaluation value transmitted from the camera side, and the adjusting means. Since the control values such as the driving speed and the driving direction of the are calculated and the control values are changed according to the type information of the evaluation value, no matter what kind of lens is attached, it is optimal for each lens. It is possible to realize a lens unit that can determine various driving characteristics and can stably capture an image of a target main subject under all subjects and shooting conditions.

Depending on the type information, for example, a high pixel CCD
It becomes possible to upgrade the version such as changing the content and type of the control signal from the camera side, and by optimizing various controls according to that version, it is highly expandable and will not become obsolete forever It is possible to realize a lens unit capable of stably capturing a target main subject depending on the subject and shooting conditions.

According to the seventh aspect of the invention, the image pickup state is detected on the camera side, and the evaluation value of the image pickup state and the type information of the evaluation value are transmitted to the lens unit side. According to the type information, it is possible to determine the optimum drive characteristics for each lens regardless of which lens is mounted, and it is possible to realize a lens unit capable of stably capturing a target main subject under all subjects and shooting conditions.

Further, the type information makes it possible to implement a version upgrade on the camera side, which is highly expandable, does not become obsolete for a long time, and can realize a camera capable of stably capturing an intended main subject under all subjects and shooting conditions.

[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 diagram specifically showing evaluation values and version information that are communicated between the camera side and the lens side in the embodiment of the present invention.

FIG. 5 is a flowchart for explaining a process performed by a lens microcomputer in the lens unit.

FIG. 6 is a flowchart for explaining a version matching method for communication between the camera body and the lens unit.

FIG. 5 is a diagram showing communication timing between a camera body and a lens unit.

FIG. 7 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 115 Data Read Program 116 Lens Microcomputer 117 AF Control Circuit 118 Motor Control Circuit 125 Focus Motor 126 Motor Driver

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 30, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a block diagram showing a 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 evaluation values according to the present invention.

FIG. 4 is a diagram specifically showing evaluation values and version information that are communicated between the camera side and the lens side in the embodiment of the present invention.

FIG. 5 is a flowchart for explaining processing performed by a lens microcomputer in the lens unit.

FIG. 6 is a flowchart for explaining a version matching method for communication between the camera body and the lens unit.

FIG. 7 is a diagram showing communication timing between a camera body and a lens unit.

FIG. 8 is a block diagram showing a typical configuration of a conventional automatic focus adjustment device.

[Explanation of Codes] 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 115 Data Read Program 116 Lens Microcomputer 117 AF Control Circuit 118 Motor Control Circuit 125 Focus Motor 126 Motor driver

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // G03B 17/14

Claims (7)

[Claims] 1. 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 focus lens of an optical system based on increase / decrease in level of the output signal of the extracting means. A driving means for driving the focus lens based on the control means; and a driving means for driving the focusing lens based on the control means. The focus lens is configured to be driven by arranging the drive means in a lens unit and passing information indicating the output of the extraction means and the type of the focus signal from the camera side to the lens unit side. A camera system characterized by the above. 2. The camera system according to claim 1, wherein the control unit is configured to change a control method of a focus adjustment operation according to type information of the focus signal. 3. The speed control device according to claim 2, wherein the extraction means has a filter for extracting a specific frequency component from the image pickup signal, and the control means speeds the focus adjustment operation according to the type information of the focus signal. Alternatively, the camera system is configured to change a threshold value for changing the operation. 4. The camera according to claim 1, wherein the camera body is provided with a focus adjustment control condition of the lens unit.
A camera system comprising means for changing the focus signal and the type information to be delivered to the lens unit. 5. A lens unit attachable to and detachable from a camera body having a focus detecting means, the receiving means receiving a focus signal and type information of the focus signal transmitted from the camera side, and the receiving means. A control means that determines the focus state based on the received focus signal, calculates and determines the focus lens drive speed and drive direction, and changes the control method of the focus adjustment operation according to the type information of the focus signal. And a drive unit for driving the focus lens based on the calculation result of the control unit. 6. A lens unit attachable to and detachable from a camera body, comprising: adjusting means for adjusting an image pickup state; and receiving means for receiving an evaluation value of the image pickup state and type information of the evaluation value transmitted from the camera side. And, the image pickup state is determined based on the evaluation value received by the receiving unit, the control values such as the driving speed and the driving direction of the adjusting unit are calculated and determined, and the type information of the evaluation value is set. A lens unit comprising: a control unit that changes the control value in response to the control value; and a drive unit that drives the adjustment unit based on a calculation result of the control unit. 7. A camera in which a lens unit is attachable / detachable, detecting means for detecting an imaging state, an evaluation value of the imaging state detected by the detecting means, and type information of the evaluation value, the lens unit. The lens unit side is capable of adjusting the imaging state based on the evaluation value and changing the adjustment method according to the type information. And the camera.