JPH04321383A - Electronic image pickup device with replacement lens - Google Patents

Abstract

PURPOSE:To realize the electronic image pickup device using a replacement lens in which stable automatic exposure is controlled even when a lens unit is replaced. CONSTITUTION:The device is provided with a camera unit CM consisting of an exposure control signal generating means 10 receiving a signal resulting from A/D-converting a luminance signal Y and a reference signal to generate an exposure state control signal, a lens unit LS consisting of a lens microcomputer and iris control data generating means 21 receiving an exposure state control signal and an iris state signal of an iris 2 and generating an iris control data, and with a data channel 20, and the lens unit divides the exposure state control signal received from the camera unit for a prescribed number of times within one communication period to generate and output an iris control data and drives the iris 2 for a prescribed number of times for exposure control.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic imaging device using an interchangeable lens, which is composed of a camera unit and a lens unit, and is capable of communicating control data from the camera unit to the lens unit.

0002

[Prior Art] In recent years, video tape recorders (hereinafter referred to as VT
With the development of video equipment such as the R (referred to as R), the use of interchangeable lenses, which has conventionally been common in silver halide cameras, is now being used in camera-integrated VTRs and the like. When multiple interchangeable lenses are used in a VTR, etc., as described above, the exposure state control signal is normalized and encoded from the information signal to ensure sufficient compatibility of the lens control information to the lens unit. There is a prior art for transmitting information.

FIG. 1 is a block diagram showing an example of a prior art electronic imaging device using an interchangeable lens, and the configuration and operation will be explained with reference to the same figure. The camera unit CM on the right side and the lens unit LS on the left side are removable by the mount part MT shown by the dashed line in the center of the figure.

The object image formed on the imaging surface of the image sensor 3 via the lens optical system 1 and the iris 2 is photoelectrically converted by the image sensor 3 and output as an image signal, which is sent to the camera signal processing circuit. 4 and undergoes γ (gamma) conversion etc., and the color signal C and luminance signal Yγ are output as video signals, and are formed into a composite video signal etc. by an encoder 5 such as NTSC and sent to the camera unit CM.
output from the section.

Further, the luminance signal Y output from the camera signal processing circuit 4 is processed by a detection circuit 6 in order to generate a control signal for controlling the iris 2 to obtain proper exposure according to the luminance state of the screen. The wave is detected, converted into digital data by an analog-to-digital converter (hereinafter referred to as AD converter) 7, and then sent to the camera microcomputer (
(hereinafter referred to as a camera microcomputer) 10. Further, a reference voltage generator 8 generates a reference value, an AD converter 9 converts it into digital data, and the camera microcomputer 10 generates a reference value.
The input from the luminance signal is normalized.

[0006] The normalization calculation process at this time is performed, for example, by the following calculation. Di=(Yc-Yb)/(Yr-Yb)X32 However,
Di: Iris data Yc: AE control signal Yr input to the camera microcomputer:
Yc level Yb at reference level: A coded exposure state control signal is obtained by calculation of Yc level or higher when the image sensor is light-shielded.

Next, the structure and operation of the lens unit LS will be explained. The exposure state control signal inputted to a lens microcomputer (hereinafter referred to as lens microcomputer) via a data communication path 20 drives the iris 2 by an actuator 24 via a D/A converter 22 and a driver 23.

FIG. 3 is a flowchart showing the operation of the conventional example. First, the operational flow of the camera microcomputer will be explained. Step S1: Take in the output of the detection circuit 6 from the AD converter 7. Step S2: Take in the reference level from the AD converter 9. Step S3: Create an exposure state control signal by normalization calculation. Step S4: Wait until some Vsync (video vertical synchronization signal) input timing. Step S5: Set the chip select signal. Step S6: The exposure state control signal is parallel-serial converted and transmitted from the camera unit CM to the lens unit LS. Step S7: Reset the chip select signal.

Next, the operation flow of the lens microcomputer 21 will be explained. Step S8: Confirm chip select input. Step S9: Take in the exposure state control signal from the data communication path 20. Step S10: The current aperture state is sent to the A/D converter 31.
Incorporate more. Step S11: Create iris control data from the exposure state control signal and the current aperture state. Step S12: D/A the created iris control data
It is sent to converter 22.

[0010] As described above, control information is communicated between the camera unit and the lens unit, thereby attempting to realize aperture control similar to automatic aperture control in silver halide cameras. .

[0011]

[Problem to be solved by the invention] The camera integrated type V
With the TR technology, there are no particular problems with automatic exposure adjustment under specific shooting conditions. However, considering the transient operation when the light intensity changes, → the detection output changes →
The operation of outputting iris drive data → performing communication → driving the iris → changing the amount of light → changing the detection output is repeated. At this time, in order to use an interchangeable lens, iris drive data is transmitted in synchronization with Vsync, so the presence of communication causes a delay in iris drive.

If the loop gain of the automatic iris control system for automatic exposure control is high, the iris control operation will go too far, resulting in an image that is difficult to see just before it stabilizes, and in the worst case, hunting. arise.

The present invention has been made to solve the problems of the prior art described above, and an object of the present invention is to provide an electronic imaging device using interchangeable lenses that is capable of stable automatic exposure control even when lenses are replaced. That is.

[0014]

[Means for Solving the Problems] Therefore, the electronic imaging device using an interchangeable lens according to the present invention inputs a signal obtained by detecting and digitally converting a luminance signal and a reference signal, creates an exposure state control signal, and transmits the signal to the lens unit. a camera unit having an exposure control signal forming means for transmitting, a lens unit having an iris control data forming means for inputting the exposure state control signal and the iris aperture state signal to create iris control data, and the exposure state control signal. This is an electronic imaging device using an interchangeable lens, which is equipped with a data communication path for transmitting information from the camera unit to the lens unit, and has a lens unit removably attached to the camera unit. and divides the exposure state control signal received from the camera unit into a predetermined number of times within one communication period to create and output iris control data, and performs exposure control by dividing the iris drive into a predetermined number of times. The purpose of the present invention is to achieve the above object by a configuration characterized by the following.

[0015]

[Operation] With the above configuration, the exposure control signal forming means
The photoelectrically converted luminance signal of the subject is detected, the digitally converted signal and the reference signal are inputted to create an exposure state control signal, and the signal is sent to the lens unit via the data communication path.

In the lens unit, the iris control data forming means inputs the exposure state control signal and the iris aperture state signal to create iris control data. At this time, the iris control data forming means converts the exposure state control signal received from the camera unit into 1 by the counting means.
The iris control data divided into a predetermined number of times within one communication period are created and outputted, and the exposure control is performed by dividing the iris drive into a predetermined number of times and repeating them.

With the above control, from the time when the exposure control signal is created by the exposure control signal forming means, the transmission delay of the control signal that occurs due to the transmission of the exposure state control signal by the communication means, and the driving of the iris and its It is possible to prevent automatic exposure control from becoming unstable, which was previously unavoidable due to a time delay between the change in the resulting brightness signal and the input to the exposure control signal forming means, and to maintain stable automatic exposure even when changing lenses. Control can be implemented.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic imaging device using an interchangeable lens according to the present invention will be described below with reference to embodiments. The block configuration of an embodiment of the present invention is similar to FIG. 1 shown in the description of the prior art, so it will be explained with reference to FIG.

In FIG. 1, the configuration and operational flow related to processing and communication on the camera unit CM side are the same as those in the preceding example, so repeated explanation will be omitted.

The camera unit CM on the right side and the lens unit LS on the left side can be attached and detached by a mount portion MT shown by a dashed line in the center. The exposure state control signal created on the camera unit side is transmitted to the lens unit LS. The data communication path 20 is connected to a lens microcomputer 21, and all communication data is once received by the lens microcomputer 21.

The received exposure state control signal is converted into an A/D converter 31 by converting its value and the current output value of the aperture encoder 30.
The iris control data value is converted into an iris control data value selected by the digitally converted value at
is converted into an analog value, and the iris 2 is driven via the driver 22 and actuator 24.

The exposure control is performed by dividing the exposure state control signal into a predetermined number of times, measured by a counting means provided in the lens microcomputer 21, and controlling the iris drive a predetermined number of times at regular intervals. is executed.

The operation flow of the lens microcomputer 21 will be explained with reference to the flowchart shown in FIG. Main routine step S20: Confirm input of chip select. Step S21: An exposure state control signal is taken in through the data communication path 20. Step S22: Enter an initial value into the execution count counter (temporarily set to n). Step S23: Find the control execution interval from the communication cycle. Step S24: Divide the exposure state control signal into n parts and calculate one exposure control output. Step S25: Start a timer.

Interrupt routine step S26: The current aperture state is transmitted to the A/D converter 31.
Incorporate more. Step S27: Create iris control data from the exposure state control signal and the current aperture state. Step S28: Send the converted iris data to the D/A converter. Step S29: Subtract 1 from the execution count counter
If = 0, the interrupt ends. Step S30: If n=0 is not determined in step S29, interrupts are enabled and the process ends.

According to the above control, the iris control based on the exposure state control signal is executed divided into n times, so that excessive driving of the iris, hunting, etc. can be prevented.

In the above configuration, the camera microcomputer 10 forms an exposure control signal forming means for creating an exposure state control signal and transmitting it to the lens unit, and the lens microcomputer 21 forms an iris control signal generating means for creating iris control data. It forms a data forming means and a counting means for measuring the number of times the iris is controlled.

[0027]

As explained above, according to the present invention, the camera unit detects the photoelectrically converted luminance signal of the subject and creates an exposure state control signal from the digitally converted signal and the reference signal, and performs data communication. The signal is sent to the lens unit by the optical path. The lens unit creates iris control data from the received exposure state control signal and iris aperture state signal. At this time, the iris control data forming means creates and outputs iris control data by dividing the exposure state control signal into a predetermined number of times within one communication period using the counting means, and performs exposure control by dividing the iris drive into a predetermined number of times and repeating it. I do.

With the above control, from the time when the exposure control signal is created by the exposure control signal forming means, the transmission delay of the control signal that occurs due to the transmission of the exposure state control signal by the communication means, and the driving of the iris and its It is possible to prevent automatic exposure control from becoming unstable, which was previously unavoidable due to a time delay between the change in the resulting brightness signal and the time when it is input to the exposure control signal forming means. With this system, there are no phenomena such as the time it takes for exposure to stabilize or hunting that occurs in conventional devices, and stable automatic exposure control can be performed at all times.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment and a prior example.

FIG. 2 is a flowchart of an embodiment.

FIG. 3 is a flowchart of a preceding example.

[Explanation of symbols]

CM Camera unit MT Mount part LS Lens unit Y Brightness signal 1 Lens optical system 2 Iris 8 Reference voltage generator 10 Camera microcomputer (exposure control signal forming means) 20 Data communication path 21 Lens microcomputer (iris control data forming means, counting means)

Claims (1)

[Claims] 1. A camera unit comprising an exposure control signal forming means for inputting a signal obtained by detecting a luminance signal and converting it into a digital signal and a reference signal to create an exposure state control signal and transmit it to a lens unit; a lens unit having an iris control data forming means for inputting an iris aperture state signal and creating iris control data;
An electronic imaging device using an interchangeable lens, comprising a data communication path for transmitting the exposure state control signal from the camera unit to the lens unit, and in which the lens unit is removably attached to the camera unit, and the lens unit has an iris control frequency. It has a counting means for measuring, divides the exposure state control signal received from the camera unit into a predetermined number of times within one communication period, creates and outputs iris control data, and divides the driving of the iris into a predetermined number of times. An electronic imaging device using an interchangeable lens characterized by controlling exposure.