JP3120239B2 - Imaging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device such as a still video camera, and more particularly to an imaging device that performs a photometric process using an image sensor as a photometric device.

[Conventional technology]

With the miniaturization of still video cameras,
One of the approaches is to use a common sensor.
Various cameras have been devised in which a white balance sensor and a photometry sensor are all performed by an imaging sensor.

The aperture and electronic shutter of the above-described conventional still video camera will be described with reference to FIGS.

FIG. 2 is a diagram showing drive H timing of the electronic shutter (details will be described later), and FIG. 3 (a) is a diagram showing the shape of the aperture of a conventional still video camera.

In FIG. 3 (a), each of # 1, # 2, # 3, and # 4 having different aperture diameters of the fan-shaped aperture blades 3a has AV F22, F11, and F4.
It is configured to support 5.6 and F.2.8. Combinations of these four types of apertures and electronic shutters are selected in accordance with the solid line portions of the program diagrams in FIGS. 2A and 2B to obtain an appropriate exposure. When these are used as photometric sensors, the aperture # 1 is F22, the aperture # 2 is F11, and the aperture # 3 is F5.
6 and # 4 are sequentially selected as F2.8, and the respective electronic shutters are driven to calculate and determine an appropriate aperture and an electronic shutter based on the video signal output level, and the main exposure for the next recording is performed.

[Problems to be solved by the invention]

As described above, in the conventional example, when obtaining proper exposure, # 4 (F28) in the program diagram of FIG.
The shutter speed (TV) corresponding to each of the EVs 8, 10, 12, and 14 with a circle is 1 / 30se
c, 1/125 sec, 1/500 sec, 1/2000 sec.

These electronic shutters are driven by a reset pulse (Reset) and a read pulse (Read) as shown in FIG.
The shutter time is constituted by the interval of. Therefore, when the four types of electronic shutters are continuously driven, a 9V period (approximately 150 ms
c), so that there is a problem that a still video camera having a large release time lag and poor operability is obtained.

The present invention has been made under such circumstances,
It is an object of the present invention to provide an imaging device capable of completing photometric processing in a short time.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, the imaging device is configured as in the following (1).

(1) an image sensor, and an accumulation time varying means for dividing the inside of the image sensor for each of a plurality of horizontal lines so that signals of different accumulation times can be obtained in each of the plurality of horizontal lines; Integrating means for integrating signals of different accumulation times read out from the image sensor for each signal of the same accumulation time, and photometric calculation means for performing photometric calculation based on the integrated value integrated by the integrating means. Imaging device having the same.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a still video camera according to an embodiment of the present invention.

In FIG. 1, 101 is a lens, 102 is an aperture, 103 is an image sensor, 104 is an A / D converter, 105 is a digital signal processing system (hereinafter referred to as DSP), 106 is a D / A converter, and 107 is a modulator (hereinafter, a modulator). MOD), 108 is a Rec amplifier (hereinafter referred to as Rec), 109 is a disk drive (hereinafter referred to as DD), 110
Is a driver for driving an aperture, 111 is a synchronous signal generator (hereinafter referred to as SSG), 112 is a driver for driving a disk drive, 113 is a system controller, and 114 and 115 are switches 1 (SW1) and switch 2 for release, respectively. (SW2).

A denotes an accumulation time varying means, which is constituted by the system controller 113 and the SSG 111, and varies the accumulation time for each horizontal line of the image sensor 103. Reference numeral B denotes a storage unit that includes the image sensor 103 and that stores a plurality of types of data for each line for one read operation (details will be described later). C is an integrating means, which is constituted by the DSP 105 and is a means for calculating an integrated value of the video signal for each accumulation time (details will be described later). D is a photometric calculation means, which is constituted by the system controller 113 and is a means for performing a photometric calculation from the integrated value by the integration means C (details will be described later).

Next, the operation of this embodiment will be described with reference to FIGS.

First, the operation of the still video camera will be described with reference to FIG.

In FIG. 1, when the SW1 114 is turned on,
The system controller 113 controls the aperture 10 via the driver 110.
Drive 2 Then, the system controller 113 loads an appropriate shutter speed value into the SSG 111, and
Control 103. Then, the photoelectrically converted signal is converted into a digital signal by the A / D converter 104 and enters the DSP 105.
Then, an integration operation is performed in the DSP 105, and the integrated value is read into the system controller 113. This operation is repeated to determine a combination of an appropriate aperture and a shutter speed. Then, when the system controller 113 detects the ON operation of SW2 115, the aperture 102 is set to the aperture position determined at the time of photometry, the similarly determined shutter speed value is loaded to the SSG 111, and the Exposure, A / D converter 104, DSP105, D / A converter 1
After 06, it is started in advance by MOD 107 and Rec 108,
The rotation is recorded in D.D109, which can be recorded stably.

Next, the electronic shutter will be described with reference to FIG.

FIG. 2 is a diagram showing the drive timing of the electronic shutter of the image sensor 103. FIG. 2 (a) shows VD and reset (Rese
FIG. 2B is a timing chart of an address and a read or reset pulse during blanking of H, and (b ₁ ) in FIG. The lower line (b ₂ ) shows the reset operation of the j-th line and the read operation of the first line after the TV. FIG. 2 (c) is a view showing the image sensor, and the horizontal effective lines are from 1 to m.

First, in FIG. 2 (a), the reset is preceded by a pulse before the read, and the difference is the shutter speed TV.
(Arrow).

Next, the valid lines 1 to m in FIG. 2C are designated by the address bus from the SSG 111, and a reset or read pulse is issued at that timing to reset or read the designated horizontal line. Timing of the address bus and the read or reset pulses in the blanking of H is as shown in FIG. 2 (b), as in the first line of the reset upper (b _1), j-th line after the TV And the read operation of the first line are as shown in (b ₂ ).

In this case, the shutter speed TV = (j−1) × TH (horizontal period).

Thus, when the electronic shutter of the image sensor 103 is used, selection can be made at a shutter speed n times the TH.

Next, an electronic shutter drive for each line in units of four lines, which is a typical example of this embodiment, will be described with reference to FIGS.

FIG. 3 is a diagram showing the shape of the diaphragm blade, a program diagram, and the continuous drive of the electronic shutter. FIG. 3 (a) shows the shape of the diaphragm blade, FIG. 3 (b) shows the program diagram, FIG. (C) shows the continuous drive of the electronic shutter. Fig. 4 shows SSG111, A / D around the image sensor (hereinafter referred to as sensor) 103.
5 is a block diagram of the converter 104 and the DSP 105, FIG. 5 is a timing chart of the electronic shutter drive V of this embodiment, FIG. 6 is a drive H timing chart of the electronic shutter of this embodiment, and FIG. FIGS. 6 and 7 show timings of HD, address bus, and Reset, respectively. FIG. 8 is a diagram showing a correction amount for the integral value in this embodiment.

Now, with the aperture of # 4 (F2.8) in the program diagram of FIG. 3 (b), TV = 1 / 30,1 / 1 as each of EV8,10,12,14.
25, 1/500, 1/2000 sec. At this time, in FIG. 4, the system controller 113 (FIG. 1) controls the address counters 1, 2, and 3 via the bus controller 111a in the SSG 111.
Shutter speeds 1/30, 1/125, 1/500,
Load the value corresponding to 1 / 2000sec. Next, the H counter 111b and the V counter 111c are started. After the first VD, 1, 5, 9, 4n
Only for the +1 (n ≧ 0 integer) line, a reset operation for a storage time of 1/30 sec is performed from the address bus 111d of the SSG 111 (Reset in FIG. 5). The H timing is as shown in FIG. In the Reset of FIG. 5, after the next VD, the reset operation for the accumulation time of 1/125 sec is similarly performed only for the 2,6,10,4n + 2 (n ≧ 0 integer) lines of the sensor by the address counter 2. Do. In this case, the H timing is the timing shown in FIG.

Next, in FIG. 5, the address counter 3 performs a reset operation for an accumulation time of 1/500 sec only for the 3,7,11,4n + 3 (n ≧ 0 integer) lines of the sensor.

In this case, the H timing is the timing shown in FIG. Here, for the address 94, 94 = 4
Since the line has a storage time of 1/125 sec from × 23 + 2, it is an address generated by the address counter 2, and the next address “3” of H (FIG. 6) is generated by the address counter 3. This switching is performed by the selector 111f, which outputs a select signal from the decoder 111e (FIG. 4) of the VH counter.

Next, in FIG.
Only for lines 4, 8, 12, ... 4n (n ≥ 1), 1
Performs reset operation for accumulation time of / 2000sec.

The H timing is the timing shown in FIG. Here, the address “118” is an address generated by the address counter 2 and is a line with an accumulation time of 1/125 sec.

Similarly, an address "27" is an address generated by the address counter 3 and is a line with an accumulation time of 1/500 sec. The next address "4" is an address generated by the address counter 4, and is a line with an accumulation time of 1/2000 sec.

Finally, in FIG. 5, all lines are read. At this time, since Reset ,, and the timing are simultaneously performed as shown in FIG.
The timing will be described. Here, the address “13”
Is an address generated by the read address counter in the SSG. The next address "138" is an address generated by the address counter 2. Hereinafter, addresses "14", "15", "16", and "17" are addresses generated by the read address counter. On the other hand, address “4
7 "and" 24 "are the addresses invented by the address counters 3 and 4, respectively, and are the lines of the accumulation time of 1/500 sec and 1/2000 sec.

When all the lines are read out in this way, they are digitized by the A / D converter 104 and output to the DSP 105. 1/30, 1/125, 1/500, 1/2000 sec in DSP105
, An integration operation is performed for each accumulation time, and each of the four integrated data is stored in a register (not shown).

Here, the system controller 113 checks the integration end flag (not shown) in the DSP 105 through the serial I / F in the SSG 111, and when the end of the integration is confirmed, the four integrated data are transmitted from the serial I / F. The data is taken into the system controller 113. Then, these four integrated data are respectively converted into ALC30,
Assuming ALC125, ALC500, ALC2000, the integral value and ΔT
The TV determination process is performed from V as follows.

Here, ALC30, ALC125, ALC500, ALC2 at aperture # 4
As can be seen from FIG. 3B, the proper exposure value EV of 000 is
They are 8,10,23,14 respectively. Also, the following (10
As shown on page 12 to 16), the above-described integral value is obtained with aperture # 4, and the TV determination process is performed.

I ALC2000> ALC _{+ 1} ALC2000> ALC _{+ 1} means that the proper exposure value is one or more larger than EV14 as can be seen from FIG. In other words, EV
> 15, the aperture must be set to # 2 from FIG. 3B. From FIG. 3B, it is determined that TV> 1/250.

II ALC _{+ 1} ≧ ALC2000> ALC- ₁ ALC _{+ 1} ≧ ALC2000> ALC- ₁ means that the appropriate exposure value is in the range of ± 1 from EV14 as can be seen from FIG. That is, since 15 ≧ EV> 13, FIG.
From (b), when 14 ≧ EV> 13, it becomes # 3, and 15 ≧ EV> 14
In the case of, it becomes # 2. Also, according to FIG.
1/1500 ≧ TV> 1/250, and in the case of # 2, 1/250 ≧ TV> 1 /
It becomes 125.

The aperture and the TV are determined as follows by a method similar to the above.

III ALC _{+ 1} ≧ ALC500> ALC _{−1 Since} EV11 to EV13, TV at aperture # 3 (F5.6) is obtained from ΔTV (1/60 sec to 1/250 sec).

IV ALC _{+ 1} ≧ ALC125> ALC- _{1 Since} EV9 to EV11, TV at aperture # 4 (F2.8) is obtained from ΔTV (1/60 sec to 1/250 sec).

Since V ALC _{+ 1} ≧ ALC30> ALC ₋₁ EV7 to EV11, the TV at aperture # 4 (F2.8) is obtained from ΔTV (1/15 sec to 1/60 sec).

VI ALC _-1 ≥ ALC30 Out of the AE interlocking range.

The main exposure is performed from the determined aperture and TV through the above-described TV determination processing routine. Make a record.

As can be seen from the above description, the aperture is set to # 4 and ALC3
In order to obtain four integrated values of 0, ALC125, ALC500, and ALC2000, signals of four types of accumulation times are required.

In the present embodiment, as shown in FIG. 5, in one screen of the image sensor, the time of reset (Reset) and the time of reading (Read) are determined by the accumulation time (1/30, 1/125, 1/500, 1/2000). Make the interval different (reset every horizontal row in 4-row cycle (Rese
By making the time interval between t) and reading (Read) different), signals of four types of accumulation times can be read from one screen of the image sensor in a 3 V period.

On the other hand, in the conventional example, as shown in FIG.
After the signal of the accumulation time is obtained, the signal of the same accumulation time is obtained from all the screens of the image sensor. Therefore, in order to obtain signals of four types of accumulation time, it is necessary to repeat one screen reset and one screen read four times, which requires a 9 V period.

As described above, in the present embodiment, it is possible to shorten the time for obtaining four types of signals as compared with the conventional example, and to obtain a still camera with a short time lag.

In the above embodiment, four lines are used as a unit so as not to depend on the position of the screen. However, a configuration of five lines, six lines, or the like may be used.

In addition, all lines are read out,
A process such as partial photometry may be performed by discarding 1/3.

〔The invention's effect〕

As described above, according to the present invention, the photometry processing can be completed in a short time by reading out the signals of different accumulation times from one screen of the image sensor and performing the photometry processing.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of a still video camera according to an embodiment of the present invention. FIG. 2 is a diagram showing the drive timing of an electronic shutter of an image sensor. FIG. FIG. 2B is a timing chart of an address and a read or reset pulse during blanking of H, and FIG. 2C is a view showing an image sensor. FIG. 3 is a diagram showing the shape of the diaphragm blades, a program diagram, and the continuous drive of the electronic shutter. FIG. 3 (a) is a diagram of the diaphragm shape, FIG. 3 (b) is a program diagram, and FIG. (c) is a continuous drive diagram of the electronic shutter. FIG. 4 is a block diagram of the SSG, A / D converter, and DSP around the sensor of FIG. 1, FIG. 5 is a timing chart of the electronic shutter drive V of this embodiment, and FIG.
FIG. 7 is an H timing diagram of the electronic shutter drive of this embodiment, FIG. 7 is an H timing diagram continuing from FIG. 6, and FIG. 8 is a diagram showing a correction amount with respect to the integral value of this embodiment. A: accumulation time varying means B: accumulation means C: integrating means D: photometric calculation means 102: aperture 103: image sensor 104: A / D converter 105: DSP 106: D / A converter 107 MOD 108 REC amplifier 109 DD 111 SSG 113 System controller

Claims (1)

(57) [Claims] 1. An image pickup device, and an accumulation time varying means for dividing the inside of the image pickup device into a plurality of horizontal lines so that signals of different accumulation times can be obtained in each of the plurality of horizontal lines. An integration means for integrating signals of different accumulation times read out from the image sensor for each signal of the same accumulation time; and a photometry calculation means for performing a photometry operation based on an integrated value integrated by the integration means. An imaging device comprising: