JP3512465B2 - Electronic imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photography using a strobe.
The present invention relates to an electronic imaging apparatus that performs exposure control that conforms to the following. [0002] 2. Description of the Related Art Conventionally, electronic devices such as video cameras have been used.
In a child imaging device, a so-called shutter is generally used.
Exposure control was performed with speed priority. As an example,
For video cameras that conform to the NTSC standard,
The shutter speed, which is the exposure time of the camera, is 60 frames / sec.
Fixed to 1/60 sec corresponding to field rate of c
In this state, the luminance signal level obtained according to the amount of incident light is
A method in which the aperture is controlled so that the bell becomes a predetermined steady value.
The formula was adopted. FIG. 12 shows a system of the above-mentioned conventional electronic image pickup apparatus.
It is a stem block diagram. In this imaging device, a power supply
After turning on the switch (not shown),
The light passing through the lens 1 and the aperture 2 is reflected on the CCD 3
An image is formed as a subject image. The subject image was photoelectrically converted
Thereafter, the noise is suppressed by the CDS circuit 4. From CDS circuit 4
The video signal passing through the LPF 5 is imaged as a luminance signal Y.
It is introduced into the process circuit 6. On the other hand, passing through LPF5
The image signal that does not exist is
-Color separation based on coding scheme. In addition, imaging
The output of the process circuit 6 is the signal of the electronic viewfinder.
Through the signal processing circuit (EVF circuit) 7 and the display 8
Is displayed. A microcomputer (microcomputer)
The timing generation circuit 10 of the CCD according to the command of 14)
Exposure period timing is generated by the CCD drive
The circuit 3 drives the CCD 3. At this time,
, Ie, the exposure time is constant. On the other hand, the CDS circuit 4 and the LPF 5 have passed.
The Y signal is input to the video level detection circuit 9.
For example, the average voltage level of the Y signal
Recognize the state of exposure at the point. The microcomputer 14 is, for example,
If the shutter speed is 1/60 sec, it is always constant
The aperture control unit 12 is controlled so that the video signal level becomes
You. When the recording SW (switch) 13 is turned on,
The video output signal of the imaging process circuit 6 is recorded (not shown).
The video signal is output to the system and the recording of the video signal is executed. [0006] By the way, a plurality of exposures are required.
Other control means except one exposure control means
With the control of the means fixed at a fixed value,
In making the decision, the duration of the transient,
The indefinite period during which the handover changes is determined by the timer
Software masking method
If there is a
The event period is a fixed period despite being different
Standby state exists. Therefore, the above timer
Control the maximum possible period to be the timer period
Must be set, and the still image trigger switch
The shutter time lag between recording and recording
U. And the shorter the lag, the shorter the shutter
Is disadvantageous for not compromising the service. [0007] The present invention has been made in view of such problems.
The shutter time lag is as small as possible.
To provide an electronic imaging device capable of operating
The porpose is to do. [0008] [Means for Solving the Problems]To solve the aforementioned problems
Therefore, the electronic imaging device according to the present invention can be adjusted to each adjustment state.
The level of the video signal corresponding to the amount of incident light is adjusted accordingly.
A plurality of exposure control means, wherein the plurality of exposure control means
Each adjustment is now performed in a sequential sequence
And other exposure control means except one exposure control means
Under the condition that the control is maintained at a predetermined eigenvalue, the one exposure control
By performing the adjustment operation by the control means,
The absolute value of the rate of change of the level detection output of
Is detected, the other exposure is immediately
Move to the sequence of the adjustment operation by the control means
Be composed. [0009] [Function] This processing allows the shortest tie in various situations.
The clear effect that mulag is guaranteed can be obtained
You. [0010] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.
I do. FIG. 1 shows a system block diagram of an electronic image pickup apparatus.
It is a lock figure. Some configuration of the imaging device of this example
Is the same as that of the conventional electronic imaging device shown in FIG.
You. Therefore, the same components are denoted by the same reference numerals as those in FIG.
The description of the configuration, operation, and the like is omitted. In particular, in the image pickup apparatus of this embodiment,
(Microcomputer) 20 controls the exposure of CCD3.
The light time, that is, the shutter speed is determined, and the microcomputer
In response to the command of 20, the CCD timing generation circuit 21
The exposure period timing is generated by the
It is assumed that the CCD 3 is driven by the path 22. Further, the CDS circuit 4 and the LPF 5 have passed.
The Y signal is input to the video level detection circuit 23.
For example, the average voltage level of the Y signal
Recognize the state of exposure at each time point. The microcomputer 20 is
At the same time as determining the shutter speed,
By controlling the aperture control unit 24 as a means, for example,
When the shutter speed is set to 1/60 sec, the video level
The reference level Vref is compared with the reference level Vref according to the level detection output Vt.
When Vt> Vref, control is performed in the direction in which the diaphragm 2 is closed.
You. When Vt <Vref, the aperture 2 is opened
Control. In this way, the video signal level that is always constant
The feedback control is performed in the following direction. In taking a still image,
The discrimination means built in the microcomputer 20 detects the video level.
How to shoot by applying the strobe with the output Vt
Or discriminate. If it is determined that strobe light is required,
The diaphragm 2 is set to an open state or a state close thereto, and
The flash unit 26 strikes through the flash circuit 25
Shooting is performed by performing robo emission. Also, from the strobe
The reflected light from the subject due to the light is
And the light amount is detected via the light amount integration circuit 27.
Is done. And when the integrated light amount reaches the appropriate light amount
So-called normal auto system
Strobe light control is performed. A moving picture recording SW (switch) 29,
Or when the still image recording SW (switch) 30 is turned on
Indicates that the output of the imaging process circuit 6 is modulated for electromagnetic conversion.
Etc., and moving images or still images on magnetic recording media etc.
An image signal is recorded. At this time, FIG.
As shown in, continuous reading of memory is performed for a certain period of recording.
It is possible to output still images continuously by performing
It is. The photographing operation of the apparatus having the above-described configuration according to this embodiment is described below.
About the work, the flow chart of FIGS.
This will be described with reference to the time chart of FIG. When the power switch is turned on, the flow shown in FIG.
-Chart processing starts. First, set the video recording
The shutter speed is set to, for example, 1/6 in step S1.
Fixed at 0 sec. After that, the timer 1 starts counting.
And wait for the image fluctuation period during the transient period to elapse.
(Steps S2 and S3). And after the exposure is stable,
An EVF display is performed (step S4). At this point, a recording standby state is set, and a moving image is recorded.
When SW29 is turned on, it is synchronized with the field timing.
Recording is performed in anticipation, and recording is performed by turning off the recording SW 29.
Is completed (steps S5 to S9). On the other hand, the process shown in FIG.
If the process proceeds to step S11, the still image recording SW 30 is turned on.
The still image recording SW 30 is turned on by performing an off determination process.
Is detected in step S12.
Compare the aperture value of
If the current aperture value is smaller than the comparative aperture value,
The process proceeds to step S13 to apply the light processing. Also,
If it is larger than the comparative aperture value, jump to step S16.
Pump. In this device, of the video level detection,
In addition to the average value for the entire area,
It is configured to output separately, and in this step S16
Makes a backlight determination based on the difference level between the two outputs.
In other words, the average in the central area is relative to the overall average level.
When it is smaller than the predetermined value, the backlight state is determined. And
Jump to step S13 and apply the flash emission process
You. Also, it was determined that the backlight was not in the backlight state in the above determination.
At this time, it is determined that strobe light emission is unnecessary, and
Thereafter, the process proceeds to step S21, in which the aperture and the shutter speed are fixed.
Transition to post-recording operation. The recording ends in step S21.
After that, through step S2 in FIG.
Return to 5. It should be noted that the comparison of the reference in step S12 is performed.
The threshold value is set to the illuminance threshold value that you want the flash to fire at low illuminance.
A corresponding aperture value, for example, F = 2.8 is associated. Follow
The current aperture value is smaller than the reference aperture value 2.8 above.
Flash light will be applied when It should be noted that strobe light emission processing should be applied.
Otherwise, when the process proceeds to step S13, the aperture is opened, and
The AGC gain and fix the shutter speed.
Allows variable setting within low and high limits
I do. As a result, the video level detection output Vt becomes a constant value,
That is, in order to make it equal to the reference comparison value Vref,
Counting period of timer 2 in steps S14 and S15
In the middle, the value of the video level detection output Vt and the reference comparison value Vr
ef, the feedback control process
When Vt> Vref, the shutter speed is shifted to a higher speed side.
When Vt <Vref, the shutter speed is
Each is set to shift to the lower speed side. This dynamic
Until the video level becomes stable during operation, the effective shutter speed
Since it cannot be obtained, the period is set to the standby state by the timer 2.
(Steps S14 and S15, refer to the time chart of FIG. 5).
See). Thereafter, the process proceeds to step S31 in FIG. After the lapse of the predetermined time, the video level is detected.
When the force Vt is Vt ≦ Vref, the shutter speed is fixed
Hold, and the exposure conditions for flash emission are determined (step
S32). When Vt> Vref, the aperture is open.
And the shutter speed is at the high speed limit.
The shutter speed to its limit value,
The change is permitted (step S38). At this time, Vt = Vr
The aperture is controlled toward ef, but the video is
Wait until the level stabilizes by counting the timer 3
(Steps S39 and S40). In step S41, the aperture is fixed.
And set the exposure conditions by flash emission,
Proceed to S33. Thereafter, in steps S33 to S37,
Execute flash emission and exposure. Further, step S42
45 to 45, the recording of the video signal on the recording medium is executed.
You. Thereafter, the flow of FIG.
It returns to step S5. In the case where strobe light emission is performed,
As described above, the light emission timing signal is sent from the microcomputer 20.
To start flash firing, but then
The reflected light of the subject is received by the photo sensor 28 and
When the photocurrent integration value corresponding to the positive exposure amount is reached,
Flash emission is stopped. After discrimination of the strobe light emission, the strobe light emission
Control timing and video level detection output
FIG. 5 shows the state of the change of Vt.
3 types of t <Vref, Vt = Vref, Vt> Vref
After the count period of timer 2 expires
Vt ≦ Vref (the reference comparison
Value) will be described in detail using specific values.
You. First, when Vt <Vref, the aperture
Table 1 shows changes in shutter speed and gain increase. [0027] [Table 1]In this case, as shown in Table 1 above, the timer 2
Aperture value in the EVF output state before time T1 when
Is F1.4 (open), shutter speed is 1/60 sec, A
When the gain of the GC is +6 dB, Vt =
Suppose Vref. After the aperture and gain are fixed, touch
Enters the counting period of Immer 2, but the aperture is fixed to the open state
And the gain is changed from +6 dB to 0 dB and fixed.
Therefore, the level of the video level detection output Vt temporarily drops
You. The shutter speed can be changed in the direction of Vt = Vref.
However, it changes because of the low speed limit of 1/60 sec.
It will not be. As a result, at time T2, the detection output V
t becomes a stable level, the shutter speed is fixed, and thereafter,
Flash light emission is performed. When Vt = Vref, the aperture is limited.
Table 2 shows changes in shutter speed and gain increase. [0030] [Table 2] In this case, as shown in Table 2 above,
Aperture value in the EVF output state before time T1 when
Is F2, shutter speed is 1/60 sec, AGC gain
Vt = Vref when the up amount is 0 dB.
Suppose. After the aperture and gain are fixed, the timer 2
However, the aperture is changed to F1.4 and fixed.
Since the gain amount is fixed at 0 dB, the video
The level of the bell detection output Vt temporarily rises. Shutter speed
Can be changed in the direction of Vt = Vref,
Transition to the side. At time T2, the detection output Vt is stable
Level and the shutter speed is fixed at 1/120 sec.
You. After that, flash emission is performed. When Vt> Vref, the aperture is limited.
Table 3 shows changes in shutter speed and gain increase. [0033] [Table 3] Timer 2 starts as shown in Table 3 above.
The aperture value is F5. In the EVF output state before time T1.
6. The shutter speed is 1/60 sec.
It is assumed that Vt = Vref under the condition that the loop amount is 0 dB.
I do. After fixing the aperture and the gain, the timer 2
During the und period, the aperture was changed to F = 1.4 and fixed.
Since the gain amount is fixed at 0 dB, Vt rises once
You. The shutter speed can be changed in the direction of Vt = Vref.
However, the maximum shutter speed is 1/500 sec.
Therefore, Vt ≦ Vref is not satisfied. Therefore,
The shutter speed is fixed at 1/500 sec of the high speed limit,
Release the fixed state and enter the count period of timer 3.
You. Vt temporarily drops, and the aperture becomes Vt = Vref.
It moves in the direction. As a result, the detection level V at T3
t reaches a stable level, after which the aperture is fixed and the strike
Robo emission is performed. As described above, the imaging apparatus of this embodiment is
When shooting a moving image, the aperture and shutter are controlled by the luminance information of the video signal.
Speed and video signal amplification are automatically controlled in a closed loop.
In addition, when shooting still images,
When it is determined that light emission is necessary, it is open or relatively close to this
Automatically controlled by the aperture to reduce loss of flash light
And improve efficiency. Next, electronic photographing according to one embodiment of the present invention will be described.
The imaging device will be described with reference to FIGS. Before describing this embodiment, the purpose of the present invention will be described again.
I will explain. That is, in the example of FIG.
To one exposure control as shown in the flowchart of FIG.
Control of other means except for means is fixed at a fixed value
In determining the remaining adjustment values for the state,
Event period, that is, an indefinite period of transient
Means, for example, steps S2 and S3, and step S1
4, 15 and timers 1 in steps S39 and 40, etc.
Software sequence for masking by a few times
The method is adopted. By this means, before entering the control
Transient periods are different depending on the situation
Nevertheless, a standby state for a certain period exists.
Therefore, the control by the timer of the device in the above example is not possible.
The longest period with a timer must be set as the timer period,
Recording is actually performed after the still image trigger switch is turned on.
The shutter time lag before the image is displayed becomes longer.
And if such a shutter time lag is long, it will be long
Disadvantageous for capturing the photo opportunity accurately
State. Therefore, the imaging apparatus according to the present invention has
It is intended to solve various problems. That is, in the apparatus of this embodiment,
FIG. 6 shows a flowchart after the shutter speed is fixed.
Thus, the video level detection output data Dn at time n-1
-1 and data at time n, which is a short time after this time
Dn is sequentially compared with a predetermined value k, and the difference (immediately
That is, the change rate of the detection level of the video signal) is equal to the predetermined value k.
The next sequence when it is smaller than k or k
Time lag by shifting to
Can be reduced. FIG. 7 is a time chart of the adjustment control.
FIG. 8 is a block diagram around the adjustment signal output unit.
You. As shown in these figures, the video level detection circuit 4
For example, the video level detection output Vt, which is the output from
For example, when the shutter speed is fixed,
And n and n-
1 is reset to the latch circuits 43 and 44. video
Video level detection as output from level detection circuit 41
The output Vt is A / D times by the sampling clock signal.
A / D converted by the path 42, and at time n and n-1
The data Dn and Dn-1 are latched. And subtraction
The result of subtraction of data Dn and Dn-1 by the circuit 45 is compared.
The data is sequentially transmitted to the circuit 46. Referring to the time chart of FIG.
data and time n at the clock timing corresponding to n
Difference from clock timing data corresponding to -1
Of the data Dn-D (n-1) are sequentially
This is supplied to the comparison circuit 46. Comparison circuit 4
6 is a ratio in which data that is a preset threshold is stored.
Data k in the comparison data ROM 47 and the result of the above-described sequential operation
And the difference between the two data is | Dn-D
When (n−1) | ≦ k, the control indicating the end of the adjustment is performed.
A roll signal is output, and the data operation ends. As described above, in the apparatus of this embodiment, the transistor
Vt is constantly monitored during the event period,
When it is determined that there is no blur, immediately the next sequence
Transition. This process allows for the shortest tasks in various situations.
It has a clear effect that the imlag is guaranteed.
Wear. It is noted that | Dn-D (n-1) | ≤k
In this case, the judgment result satisfies the condition several times consecutively
To make the transition to the next sequence
It is also possible to prevent mistakes. Next, another example of an electronic image pickup apparatus will be described.
This will be described with reference to FIG. In the image pickup apparatus shown in FIG. 1, the flow chart shown in FIG.
-As shown in the chart, after discriminating strobe application,
Video signal level Vt ≦ Vref? Size
If the result does not correspond to this condition, the process proceeds to step S38.
The shutter speed is released at the same time
Is fixed to the high speed limit. In contrast, the
In determining the high speed limit value,
For the effective period of the flash waveform of the maximum flash of the
Longer period is the exposure period for strobe and ambient light.
The upper limit value of the shutter speed is set as described above. Strobe light emission according to the time chart of FIG.
First, the photoelectric conversion of the CCD will be described.
The photocells corresponding to the
To discharge the previous charge. After the discharge actually
Exposure period depends on the flash trigger timing
The flash is fired, and the flash fires after the expiration date.
Transfer to transfer to vertical shift register
The exposure period ends according to the gate timing. So
After the transfer of the vertical and horizontal shift registers
Image transfer will be performed. As described above, in the imaging apparatus of the present embodiment,
From the trigger timing to the transfer gate
By securing at least the period, the strobe light
The quantity is processed so that it can be used efficiently. Of course
If such limit shutter control is not performed,
The effective period of the strobe light will extend beyond the light period.
Waste energy. Here, the exposure end timing is
Limit the effective time of the maximum flash emission, and
Generates charge discharge timing before flash emission timing
Immediately after discharging the charge as the limit timing.
To give a strobe trigger to
As a concept, charge discharge and strobe trigger are almost the same time
The transfer gate timing for a long time.
The same result can be obtained even if the
can get. Next, another example of an electronic image pickup apparatus will be described.
This will be described with reference to FIGS. The image pickup apparatus of the present embodiment has a
After the switch is turned on, apply flash photography to the
If you decide what you need to do,
Switching to still image output and displaying EVF
Things. FIG. 10 shows the image pickup apparatus of the present embodiment.
FIG. 10 is a block diagram of an EVF display-related unit in FIG.
The components other than those shown in FIG.
It shall be common to that shown in the figure. The structure shown in FIG.
Even if it is a component, the component is the same as that of the above example
Will be described with the same reference numerals. As shown in FIG.
The video signal output from 6 passes through an A / D conversion circuit 51.
1 field under the control of the memory controller 54
Image information is recorded on the field memory 52.
Swelling. At the same time, the output of the field memory 52
Is configured to be able to go around and take out. The output of the memory 52 is supplied to the D / A conversion circuit 5
3 and enter one end of switch SW (switch) 55
The other end is connected to the direct input side of the imaging process circuit 6.
Has become. The common terminal side of this switch SW55 is
Connected to EVF circuit 7 to enable image display on display 8
Has become. Further, the common terminal side is connected to a modulation recording system.
SW to control the image signal output of
(Switch) 56 is also connected. The microcomputer 60 includes a memory controller 5
4 timing control and EVF output imaging process circuit
6 and the continuous video from the field memory 52
Switch to a still image, control the recording operation, and the like. The imaging apparatus of the present embodiment configured as described above has
The EVF display operation in FIG.
According to each processing timing of the imaging processing flowchart of FIG.
Referring to the time chart of FIG. 11, first,
After discriminating the flash photography, the step S13 of FIG.
Image fluctuation during the transient period in the imaging Ta
Is not output to the display 8, the switching SW 55
From the video output state from the imaging process circuit 6
Switch to the still image output state from the
You. At this time, the field memory 52
And only reading is repeated. Its display time
Is the output period of still image 1 in the time chart of FIG.
Indicated by Next, step S in the flowchart of FIG.
At the timing Tb of 34, the strobe light emission
Flash light emission, exposure at timing Tc of step S37
Complete. In step S43, the field
Video signal passes through the A / D conversion circuit 51 and is
It is written to the memory 52 at the timing Td and is repeated at the same time.
Return readout, repeatedly output to EVF circuit 7 as mode
Power. The display timing is shown in the time chart of FIG.
The output period of the still image 2 is shown in FIG. The output of the EVF circuit 7 is at the timing Ta.
From a point image to an image equivalent to a recorded image with strobe light
It can be switched and the photographer can confirm. Then, as shown in FIG.
Still image recording ends at the timing Te of step S45,
The output of the EVF circuit 7 is also the same as when the moving image is output in the initial state.
The direct output signal of the image processing circuit 6 is output and displayed.
You. As described above, the image pickup apparatus according to the present embodiment employs the EVF
Flash shooting should be applied when shooting still images in display
When the video is discriminated or before
By switching from force to still image output, for example,
5 during the period from the timing Ta to Tb.
Of the video level detection output Vt as shown in the
The image fluctuation due to the change, and further, the timing Tc to T
Including strobe light from the image of only
Freezes the top screen at any time in response to momentary changes to the image
This can give the photographer an uncomfortable feeling
EVF display without the above is possible. [0060] As described above, the electronic imaging apparatus according to the present invention is used.
For example, always monitor Vt during the transient period.
And when it is determined that there is almost no change in Vt,
At this time, the process proceeds to the next sequence. By this process, various
Clear that the shortest time lag is guaranteed in the situation
Effects can be obtained. In the above embodiment, | Dn-D (n-1)
For the determination of | ≦ k, the result of the determination is continuously several times.
So that we can move on to the next sequence
In this case, it is possible to prevent a determination error.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system block diagram of a certain electronic imaging device. FIG. 2 is a part of a flowchart of a photographing process in the image pickup apparatus of FIG. 1; FIG. 3 is a part of a flowchart of a photographing process in the image pickup apparatus of FIG. 1; FIG. 4 is a part of a flowchart of a photographing process in the image pickup apparatus of FIG. 1; FIG. 5 is a time chart in a photographing operation of the image pickup apparatus of FIG. 1; FIG. 6 is a flowchart after fixing a shutter speed in the electronic imaging apparatus according to the embodiment of the present invention. FIG. 7 is a time chart of adjustment control of the imaging apparatus of FIG. 6; FIG. 8 is a block diagram around an adjustment signal output unit of the imaging apparatus of FIG. 6; FIG. 9 is a time chart of a flash emission operation of another example of the electronic imaging apparatus. FIG. 10 is a block configuration diagram of an EVF display-related portion of still another example of the electronic imaging apparatus. FIG. 11 is a time chart of an EVF display operation of the imaging device of FIG. 10; FIG. 12 is a block diagram of a conventional electronic imaging device. [Description of Signs] 3 CCD (imaging element) 20 Microcomputer 23 Video level detection circuit 24 Aperture control unit 41 Video level detection circuit 42 A / D circuits 43 and 44 Latch circuit 45 Operation circuit 46 Comparison circuit Vt Video level detection output Dn, Dn-1 data

Claims (1)

(57) [Claims] [Claim 1] Corresponding to the amount of incident light according to each adjustment state
Multiple exposure control means to adjust the level of the video signal
The plurality of exposure control means are arranged so that each adjustment is performed sequentially.
And exposure control.
Control of the exposure control means other than the control means to a predetermined eigenvalue.
Adjustment operation by the exposure control means under the condition
Changes in the level detection output of the video signal
It is detected that the absolute value of the rate has fallen below a predetermined threshold
Sometimes, the adjustment operation is immediately performed by another exposure control unit.
Characterized by being configured to shift to the sequence of
Electronic imaging device.