JPS6032482A - Imaging device - Google Patents

Abstract

PURPOSE:To improve respondence of a controlled system, by making signal reading operation from an image pickup device plural number of times during one standard TV field period. CONSTITUTION:When a mode changing switch MSW is connected to (a) side the mode becomes the first exposure mode. By making a power source on, dark current component in CCD 1 is cleared. Then, charge accumulation of photometry is made during scanning period of F1 field, and the charge is vertically transferred in the next vertical blanking period and accumulated in a memory. The charge is read out at every 1H in the next F2 field period, and integrated by an integrator of a signal processing circuit 34. When integration of a measuring section is completed, the integration signal is A/D converted and calculated, and optimum aperture value is determined. The aperture is controlled basing on the value. The charge accumulated in CCD 1 during photometric operation is cleared. Then, charge accumulation is made according to shutter time and recorded in a recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an imaging device suitable for obtaining exposure information and focus adjustment information.

(Prior art) Conventionally, in this type of device, photometric information is obtained by scanning and driving an imaging IW means such as an image pickup tube or a semiconductor image sensor in synchronization with the speed-based television system, and integrating the total output of at least a portion of the IW means. The state of some of the periodic scanning outputs (
For example, by detecting the contrast state), information regarding the focus adjustment state was obtained.

In such devices, the above photometry or distance measurement information is J4.
↓The drawback was that it could only be obtained for at least one television field period.

Such drawbacks do not pose much of a problem in general video cameras and the like.

For example, if we consider the aperture as a control system, conventional video cameras have an auto-iris that servo-controls the aperture using the output of the imaging means, but if this auto-iris is constantly controlled in a j-to-j loop, for,
Since the servo error signal is small, except for objects with particularly marked changes in brightness and darkness, the time required for control is short.

Therefore, as mentioned above, the defects are not as obvious.

However, when such an imaging device images only one screen, the above drawbacks become a big problem. That is, when imaging only one side, it is necessary to turn on the power immediately after 44 seconds in order to save power.

However, with such a configuration, since the servo loop is stopped until then, it will take several fields of time for the servo to stabilize at the target value.

Considering the responsiveness of flilJs such as auto iris and the stability of the servo, it is not possible to unnecessarily increase the amount of flIlJ to be adjusted at once.

Moreover, considering, for example, the hw of 18 degrees, the dynamic range of an imaging device, especially a semiconductor imaging device, is much narrower than that of a conventional @salt camera, so high exposure accuracy is required.

Furthermore, even if there is some exposure error with silver halide film, it can be corrected considerably in the laboratory, but with an image pickup device, it is necessary to avoid making adjustments each time by turning the receiver side away.

Therefore, AE failure is not allowed.

In order to image one screen in this way, the imaging device uses AE that has a fast start-up and high precision.

AI! 'fil, the control is reassuring. On the contrary,
For example, Jj Motoko Eda! It is also conceivable to obtain the AE control signal quickly by increasing the driving frequency of the clock generator working in X shift several times.

However, this method has the disadvantage that the horizontal transfer frequency of the image sensor becomes very high, making horizontal transfer itself difficult and power consumption increasing in proportion to the increase in frequency.

(Purpose) The purpose of the present invention is to provide an imaging device that can solve the drawbacks of the prior art, and that can obtain object information in a short time with low power consumption. An object of the present invention is to provide an imaging device that allows good control.

Another object of the present invention is to provide an imaging apparatus that can improve the responsiveness of controlled systems such as an exposure control system and a focus adjustment system.

FIG. 1 (1, 1 is a structural diagram of a frame transfer type image pickup element which does not provide a detailed explanation of the present invention. The image pickup element 1 as an image pickup means includes an image pickup section 11 which is a photoelectric conversion section, a memory part 12 that temporarily stores charges from the memory part; and a horizontal register part that vertically transfers the charges from the memory part every horizontal scanning head (hereinafter referred to as IH), then horizontally transfers them, and reads them out. 13, and an output amplifier 14 for amplifying the charge from the horizontal register.

FIG. 2 is a diagram showing an example of the configuration of the imaging device of the present invention,
30 is an imaging lens, 31 is an aperture, and 32 is a shutter.
34 is a signal processing circuit which processes the output of CCD 1 to generate a standard television signal, for example, N
While forming the TSC signal, it also supplies a video signal to the recorder 35. Reference numeral 36 denotes a drive circuit as a reading means for driving the CCDI, 37 a clock generator for supplying this drive clock signal, and 38 a sequence control 1 call circuit as a 1-sequence readout control means, which controls the driving start and the like of the CCD. stop, recording operation 1b1 of the recorder 35, operation control of the aperture shirt 1DII control circuit 39 1, 1 pivot circuit 3
6 controls the switching of the closed light extraction mode. The MSW is an exposure control mode changeover switch and has a first mode connected to the a side and a second mode connected to the b side. Reference numeral 39 denotes an aperture shutter control circuit that controls the drive of the aperture 31 and shutter 32 based on the output of the sequence control circuit 38.

Also, inside the signal processing circuit 34, C and AE as shown in FIG.
iUII? 1'111 signal generator is included. The AE signal conversion section is constructed to limit the area used for photometry. In FIG. 3, 103 is a gain control circuit, and 104 is a D.
106 is a mix circuit, 107 is an integration circuit, and 108 is an A/D converter. After the signal from the CCDI is DC-regenerated by the clamp circuit 101, it is sent to the amplifier 102.
amplified by.

The signal is guided to the next stage gain control circuit 103. This gain control circuit 10.3 is a D/A converter 104
The amplification degree is controlled by the amplification factor, but it is normally set to the standard amplification degree, and when the subject is in low illumination and the aperture is wide open, the amplification degree is increased so that the output signal level becomes an appropriate value. . The output of the gain control circuit 10'3 is led to the recorder 35 via the process circuit 05 for processing the image 46, and also to the photometric calculation system.

The mix circuit 106 of the photometry calculation circuit applies a photometry section pulse (hereinafter referred to as a wind pulse) wp to the signal via the gain control circuit 103 in order to obtain a side light video signal corresponding to the photometry section 20 shown in FIG. Multiply.

110 is a wind pulse generation circuit for defining the range of the photometry section 20 shown in FIG. As a result, mix circuit 1
Only a partial photometric signal is output from 06. Then, the signal from the photometry section is integrated in the next-stage integration circuit 107 and converted into a DC signal. The aperture/shutter control circuit 39 evaluates the photometry state using the arithmetic unit 109 and supplies the result to the aperture/shutter control circuit 39.
Shutter (feeds back to the shallow groove.

FIG. 5 is an example diagram of the block of the clock generator (7). The synchronization pulse generator 40 outputs the layered synchronization pulse of z, and 41 is this period]. to form sub-carriers.

42 forms 21'vi)Iz by dividing the frequency of the synchronizing pulse by 7, and supplies this to the H counter 43 and the ■ counter 44. [■Counter 43 performs 2MHz for 5 minutes)・ζ'',
The frequency is further divided by 13 and then divided by 2.

The divided outputs are then decoded by combining them with logic and gates to generate horizontal synchronization-related noises. ■
The counter 44 divides the frequency of the pulse frequency-divided by 65 by the LI counter by 525, decodes the pulse by ILOM, and generates a pulse related to vertical synchronization.

45 is a decoder which mixes horizontal synchronization related pulses and vertical synchronization related pulses to form a television frequency I♂.046 is an ldl l clock generator, and the output pulse of the decoder 45 is a clock pulse of 14 MHz, 2■1 z. Outputs the horizontal drive-related pulse φ□.

Also, a 47-digit second clock generator is used for decoder 4.
A vertical drive pulse φ7 is formed by the output pulse No.5.

The accumulation timing and accumulation time of the solid-state Cc element, the transfer timing, and the readout timing are controlled by the sequence of the system control circuit 38. It is structured like this. Control signals for the recorder 35 and control signals for the aperture, shutter, etc. are also output from the sequence control circuit 38. The sequence control circuit performs various controls using a 2MHz clock, but this sequence control circuit is operated by various external controls, such as the power switch, release when shooting, shutter speed, sensitivity switch, etc. is controlled.

Next, FIG. 6 is a diagram illustrating the first exposure control mode of the present invention. When the mode selector switch (SW is connected to the a side), the 1 [retraction output pulse described later from the store operation circuit 36 is outputted at the timing shown in FIG. 6, for example. indicates each field period.

When the iu source (P OWE R) is energized during the period ■, the period ■
Then, the dark current in C'CD enters the charge clearing (cLit) and L1 imaging mode. And P″ll of Kan1iJ1■
During the field scan period S1, the F& charge of the measurement board C is accumulated, and during the vertical blanking period VT of the next period (2), the charge is vertically transferred and accumulated in a part of the memory IJ.

Its mentality is 11 in period ■ within the next F2 field period.
(The clamp circuit 101, the amplifier 102, the gain control circuit 103, and the mix circuit 106 are output one after another.)
is input. In this mix circuit, the video signal is mixed with the window pulse corresponding to the photometer, so k
Only the signal corresponding to the fhlll light section is sent to the next integrator 107.
It is integrated by

When the integration of the photometric section is completed, this integrated signal becomes A in the period ■.
After the /D conversion, the calculation circuit 109 calculates the optimum aperture value and determines the optimum aperture value.Based on this value, the aperture is controlled in the period (3). Then, the charge accumulated in the CCU FC during the first photometry operation is cleared as unnecessary charge during period ■, and then during period ■
17L of charge is accumulated at the shutter time, vertically transferred during the vertical blanking period of field F4 in period 0, and recorded on the recording medium during field 55 of period (2).

In this manner, in the first exposure control mode of the image pickup apparatus of the present invention, charge accumulation and heavy transfer for photometry are performed in accordance with the chimney synchronization.

FIG. 7 is a diagram showing the second exposure control mode. The difference from the first mode is that in order to shorten the photometry time, the charge accumulation time for photometry is not carried out over the entire period of one field, but instead utilizes a part of the period between s and i field. Charges other than 21. are used in photometric calculations. Since it is a χ relationship, in such a case, high-level transfer is performed so that the photometric unit positive load can be read out quickly. With the switch MSW connected to the b side, when the power is turned on at the end of the period @ in the figure, the J liquid gland section 11Lv voltage is read out at high speed via the memory section 12 and the horizontal register 13 during the period 0. After that, the quasi-load & product in the imaging section is performed for a period (l), and this charge becomes period 0.Then, this a]i minute result is calculated in a period C, Based on this calculation result, the period [
In the phase], the synchronization control 1i11 is performed. Then, during the period [phase], the charge in the Is valley is cleared and the sheather opens again during the period [phase].
After exposure is carried out by the phase], the charges in the imaging section are vertically transferred to J 1iaj (0).

Further thereafter, recording is performed in the period O in the F4 field. FIG. 8 is a diagram showing a timing sequence of output pulses from the drive rLil path 36 in the second exposure control mode shown in FIG.

In FIG. 8, POWER is a power supply, VD is a TV vertical drive signal, and 5liCCD drive pulse.

φP1 is a charge accumulation and transfer pulse for the imaging section, φps is a charge transfer pulse for a part of the memory, and φS is a signal read pulse for the horizontal shift register.

fNi', CAL is the integral, calculation pulse, IN(,I,
Sld is the squeezing force side force control signal HUTTEI (, i: gloss control signal, EC0L is also Di-, J: recording control signal, WINJ) OW is a wind pulse.

When the power supply is turned on, unnecessary charges in the COD are cleared by a clear (CLR) pulse consisting of a pulse φpx. Since the CCD enters the photometry state, the aperture is set to a predetermined standard aperture value and the shutter is opened. After a certain arbitrary photometry period 0 has passed, the charges in the vertical direction of the screen that are not related to photometry are removed by the vertical transfer pulse VT' of the period ■.

As a result of this transfer, the charge in the photometry section has come to the part of the memory immediately before the horizontal register, so the charge corresponding to this photometry is read out every LH during the driving pulse φPsK of the part of the memory during the period @, and the window pulse. After being mixed with, it is integrated and calculated. After the aperture is controlled in a period [phase] according to the calculation result, photographing is performed and recording is performed in a period @. In this embodiment, the aperture, etc. is controlled based on the photometry result of one time, but if a good calculation result cannot be obtained depending on the initial aperture setting, or the CCD is saturated, or there is insufficient photometry time, etc. may perform photometry, transfer, calculation, aperture or shutter control until the optimum result is obtained. Generally, it takes time for aperture equipment to control h1M to the set aperture, so if the shutter is controlled to calculate the optimum aperture, the time required for photometry can be considerably shortened.

FIG. 9(a) is a diagram showing the area of the photometry section, and FIG.
b) and (C) are photometric charge vertical transfer pulses, that is, period 0. FIG. 6 is a detailed timing diagram of the @, 0 pulses.

FIG. 9(a) shows the case where the photometric section 2o has a width of 100 mm in the vertical direction of the screen.

In addition, the case where the device is a frame transfer type CCU is shown. In FIG. 9(b), when the accumulation period @ for photometry ends, the charges in the range indicated by 90 in the vertical direction in FIG. 9(a) are transferred to the horizontal shift register at high speed during period 0. removed.

Since the number of pulses in period 0 is equal to 1 TV (the number of vertical scanning lines), the number of pulses is approximately a (z4sx...) approximately 347 times.

Next, period 0. At 0, reading of the photometric section 2o in FIG. 9(a) is performed. At this time, only a signal of a predetermined width within the horizontal scanning period is gated by the wind pulse. The rainbow-gated signal from the photometer 2° is integrated and calculated.

Thereafter, in the period [phase], the scanning line signal above the photometry section 20 in FIG. 9(a) is read out within the time required to control the aperture and the like. From this point on, dark current unevenness can be prevented.

Next, FIG. 9(c) is a diagram showing another embodiment of the present invention, in which the charges corresponding to the photometry section are not read out from the horizontal shift register every j91H, but the charges of the photometry section are all added together using the horizontal shift register. This is then averaged. In this case, the horizontal transfer pulse φS stops during the period @. Further, the integrator only needs to integrate for the subsequent IH period of period 0. Thereafter, in period O, sample and hold is performed before A/D conversion, and then A/D conversion is performed and calculations are performed.

Incidentally, dark current unevenness can be prevented by supplying pulses φP8+φS even during this period O. In addition, FIG. 9(b)
In the timing diagram shown in (C), signals in areas other than the photometry section 20, especially in the lower part of the photometry area in FIG. 9(a), are vertically transferred and cleared at high speed, so that signals for photometry etc. can be obtained quickly and is useful for easier control.

In particular, in the embodiment shown in FIG. 9(C), the signals from the photometry section 20 are also added at high speed and then read out, so that signals for photometry etc. can be obtained at even earlier timing. Of course, Figure 9 (C
), we have shown an example in which only a part of the screen is used as photometric data, but instead of just a part, it is also possible to use the entire signal charge of one screen accumulated in a short time to the horizontal shift register. You can also add it.

In addition, in the embodiment shown in FIG. 9(C), the charges of multiple rows are added in the horizontal shift register, but the charges are added in the rows near the horizontal shift register in the memory part 12. It's also beautiful.

Next, FIG. 10 is a diagram showing a third embodiment of the present invention. In this embodiment, photometry and distance measurement data can be obtained multiple times within l field period T. T, ,
T is the accumulation time in the imaging unit 11 112.711.
is a vertical transfer period, during which the horizontal transfer pulse φ8 is not supplied to the horizontal shift register 13 of the COD shown in the first diagram.

The vertically transferred charges are therefore summed within this register.

Also, %'LB+'I'6 is a read period of the horizontal shift register, and it takes 4 seconds each.

If drive control is performed by the drive circuit 36 in this manner, photometry or distance measurement information can be obtained multiple times within one field. Based on this information, the camera can, for example, control exposure using the aperture,
When the lens is driven, control of the controlled system can be completed in a very short time, and even if the conditions of the subject change, it can be quickly followed.

(Effect) As described above, the signal readout operation from the imaging means of the present invention is performed multiple times within one standard television Φ field period.
Since the information obtained thereby is used for exposure control, lens position control, etc., the responsiveness of the controlled system is improved.

Therefore, even if the subject is moving at high speed, there may be focus errors caused by the AF system or exposure errors caused by the exposure system.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an imaging device suitable for the present invention, FIG. 2 is a diagram showing an example of the block configuration of the imaging device of the present invention,
3 is a diagram showing the "firυ control signal generation section," FIG. 4 is a diagram showing an example of the photometry area, FIG. 5 is a diagram showing an example of the configuration of the clock generator 37, and FIG. FIG. 7 is a diagram explaining the sequence and timing example of the second exposure control mode, and FIG. 8 is a more detailed timing example of FIG. 7. Figure 9(a) is a diagram showing a specific example of the photometry part, Figure 9(b) is a diagram showing the first embodiment of the 6111-element timing pulse, and Figure 9(C) is the same diagram. FIG. 10 is a diagram showing the third embodiment of the side light timing. l... CCD as an imaging means, 36... Drive circuit as a readout means, 38...・Sequence controller as read control means) low/l' circuit, 109...
Arithmetic circuit, 12... Part of memory, 13... Horizontal shift register, 14... Output amplifier, 37... Stomach bloat generator. Patent applicant: Canon Co., Ltd. Figure 3 fOiL ℃bar (≧ 5 points)

Claims (1)

[Claims] An imaging means for exchanging an optical image into an electrical signal, a reading means for reading out at least a part of the electrical signal formed by the imaging means, and a readout operation by the reading means for one standard television. - A projection device having a readout control means that allows readout to be performed multiple times within a field period.