JPS5838080A - Flicker preventing system for solid-state image pickup device having photometric function - Google Patents

Abstract

PURPOSE:To obtain stable picture shooting information at all times by setting starting of accumulation of photometric information and starting of accumulation of picture information at integer times of 50 milliseconds and eliminating flicker error between photometric information using the light source driven by AC power source and photographing information. CONSTITUTION:When a power supply switch for photometering is turned on and accumulation of photometric information is started in photometric elements A1, An; B2, Bn-1;...;Z1, Zn, accumulation is completed in a specified time. Then, a power supply switch for picture shooting is turned on, and accumulation of picture shooting information is started in shooting picture elements A1...An,... Z1...Zn. In this case, the interval between starting time of accumulation of metering information and that of accumulation of picture shooting information is set at integer times of 50 milliseconds. By this way, flicker error between photometric information and picture shooting information due to fluctuation of amount of light of an object illuminated by a fluorescent lamp etc. is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention stores photometric information corresponding to subject brightness in a solid-state image sensor, and stores photometric information for images based on the photometric information. This invention relates to a method for removing seven Ritzker errors between information and image capturing information.

In recent years, solid-state imaging devices such as charge-coupled devices (CCDs) have come to be used in various directions, but the output voltage of solid-state imaging devices is linearly proportional to the illuminance of the light-receiving surface. The light range is narrow, and as a method for operating it over a wide illuminance range, the charge accumulation time in the photoelectric conversion section is switched in accordance with the light-receiving surface illuminance. According to this method, the subject brightness is high and the light receiving surface illuminance is high! In this case, in order to obtain a proper charging output, an artificial light source, such as an AC
When using a power source for illumination such as a fluorescent lamp, if the image signal is read out repeatedly in a short storage time, the light source becomes
This happens when the image output signal level fluctuates each time due to flicker.

The present invention relates to a solid-state imaging device that stores photometric information corresponding to the brightness of a subject in a solid-state image sensor, and stores image shooting information based on the photometric information. To provide a method for eliminating 7Ritzker errors in photometric information and image capturing information due to fluctuations in the amount of light on a subject irradiated by an AC power source driven light source by setting the information accumulation interval to an integral multiple of 50 milliseconds. It is a turtle whose purpose is to.

The present invention will be described in detail below with reference to the drawings.〇Figure 1 is a waveform diagram for explaining the principle of the method for eliminating flicker errors according to the present invention. This is a case in which a fluorescent lamp is driven, and FIG. 1 shows a case in which a lighting device is driven by an AC power source.

The curves indicated by broken lines in the figure are the supply voltages,
The solid curve indicates the brightness of the light emitted from the lighting device. As shown in the diagram, the illumination light is supplied to the illumination device, and the light and dark changes at twice the frequency of the power source.
With this, the luminance of the illuminated subject also changes in brightness and darkness.In the case of 50Hz of 01st rlA@, the time of one cycle is m0G 10msec, so it is 50m5ec. So there will be 5 cycles.

In addition, in the case of 060 & in Figure 1, 7 lights of lighting is 1
One case is that the image information is stored at 20 Hz, and the other is that the image information is stored from time tAi to tAi.

Even when the power supply to the illumination light source is 5OHs+60)
In the case of h (B), since each object is illuminated with the same amount of light, the solid-state image sensor O photoelectric conversion output signal does not change due to the illumination of the object illumination light source. Therefore, the light source's 7 This can prevent fluctuations in the output signal due to stress. The accumulation period is 50m.
Needless to say, it is 4 times better than the period of an integer multiple of D.

Although Fig. 1 shows the case of 50Hz and @0HxO, flicker can be prevented even in the case of a power supply frequency other than that with an accumulation period of 50nm or an integral multiple of 50nm, that is, 50mm (i seconds). The time mentioned is 7 of the lighting device.
When the Ritzker period is t = 7 (esc) and the number of s cycles oWA is n', 7 Ritzker force - frequency f = 20 vs (H
z), the number of cycles n' must be a value that always yields a positive integer O solution, and the number of cycles n' is a positive integer O.
'It is said that it is given by an integer solution, but it is also an image. Since the signal integration operation of the image sensing means is always started at a predetermined timing during periodic fluctuations in brightness, as shown in O above, the signal integration and accumulation period of the image sensing means is approximately By controlling the integration and accumulation operation of the cough image sensing means No. 041 by a controlling means so that the frequency is several times as high as 50m5ecol, the illumination device is such that its flicker frequency is at least 20n (Hz). In this way, the above-mentioned disadvantages are easily solved. In this figure, predetermined pixels are selected for sidelighting. A photometric pixel selection means is provided to provide a method for obtaining photometric information in a short time through the photometry pixel selection means. ...;4.・・・
..., Zu is the photoelectric conversion element section, kite, ..., P
Aa s F bird,..., I'Bn;...; Fz
1, . . . , FiSn transfers the image information accumulated in the photoelectric conversion element section vertically and to the shift register V8it .

Charge transfer gate, kite, for transfer to vSfl.

yULn G■U口a; ...; MYt, MY
a −＠＄M'! ls1. MZr* is a predetermined photometric pixel A1g An i bird', 13ss-t;
...IYl.

Y n −x; z@, Z n K 11 The charges accumulated for the light are transferred to the vertical shift register v88.・・・
・、V8m! O charge transfer game) -CA
I t...t cZlt...t CAn ,...
These are integral clear gates for clearing unnecessary image information accumulated in the CZsu ft photoelectric conversion element section, and these gates are controlled via terminals SHμm and ICG.

■Peng, to ■ and to H, to H is direct shift register VS,
, . . . , a clock pulse input terminal for driving Van and the horizontal shift register H8, field effect transistors PC,, PC', and resistors R1 to R.

The voltage information is converted into voltage information through a charge-voltage conversion circuit consisting of the following, and image information corresponding to the subject is output from the UP terminal.

FIG. 3 shows an embodiment of a specific drive circuit of the present invention. O
20 is an oscillation circuit that outputs the clock pulse φ and a narrow reset pulse R8 that is output before the inversion of φ;
ANI~ANlG is a/toge-), ORI~OR')
INI A-IN6 is inverter DF
1 company Dfi flip, Futsubu, RFI~RF9 is R
8 flips 7p, CNI to CN5 are power 'rc2 groups 4-f - [path, WRI to WR41d Waveform shaping circuit for driving solid-state @ image element %AD1d Predetermined accumulation time setting circuit for photometry, AD2d The accumulation time setting circuit %Mte is a photometric information display means for setting the accumulation time for Iij image photography through the side light calculation circuit port n of the photometric information output from the VF terminal of the solid-state image sensor.
This is a means for recording and displaying eDPY Hiro photography information. LM
ls MFiY t DrY is not directly related to the purpose of the present invention, so the details of the 11 companies will be omitted.

SWI is a power switch for photometry, 8W2 is a power switch for photography, El is a t-source battery, and R1 is a pull-down resistor. Fig. 35A is a timing chart of the main parts of wJ4, and the driving of Figs. 2 and 3 will be specifically explained based on this.

Time to:! : When the photometry power switch SWI is turned on, a power amplifier clear (not shown) is activated in advance, and the capacitor, 7 lip-flop, etc. are reset to their final state. Time t1
Until then, and Gate ANI.

Counter CN1. D-type flip-flop DPI, inverter INI, Antogame N2. Clock pulse Vφ1. Since V6 is output, the vertical shift register U81. ..., U8! Floating chard caused by IK is cleared. During this time, the counter CN1 counts the clock pulse φ through the OK terminal, and when all the floating charges in the vertical shift register are cleared, time ttK! Then, a full count O carry is generated from the TC terminal and the Dll flip 70 knob is reversed, so at time t.
,~1t.

Time Ant Game N4. Clock pulses Hφ1 . Hφ! is output and the horizontal shift register H8O floating charge is cleared. The other day, the CNI was empty and went to Kurotsuta Pulse) L%
When all the floating charges in the horizontal shift register O are cleared, a full count carry is generated from the TC terminal at a certain time, and the D-type 7-lip 70-tub is inverted. D@Tsuritsub 70 When the Q terminal line of the 70-tube flips from “H” to “L” level, one V synchronizes with the falling attack! The cut circuit N81 indicates the time -
Generates a one-shot pulse.

- Power tip electric conversion element 11Ai, ... Muto/bow z1.・・・
・, zn are cleared via ICG while clearing the horizontal and vertical analog shift register O floating charges. Time 1. In response to the output pulse generated by N81, R8y is input via AND gate AN9.
The q terminal is “L” at O where the lip 7 and the 4-tube 1 are set.
``Flip to level and goo) ANII l?L
c"[1t4f"L'"v to s-o!c.

is output, and the accumulation of photometric image information is started. RF
When 5 is set, the Q terminal is inverted to ``H level'', so it is compared with the output of the Antoge circuit DIO to the tsuta pulse by the tick check comparator MCI.When the counter CN20 count signal and the ADZO output are equal The MH pulse is generated from the MCI, and the accumulation of photometric image information is completed at time -, and the photometric pixel ^, Mn Bl @
B! '-t e...= E Yl , Yn-t i
Z@, Zll KThe accumulated pixel information is
Charge transfer gate operation MAs; M bird, MB Otori-1・'
""; MY goose, MYn-t i MZI,
-Direct'/7 register VS, ,... through MZn
, during the accumulation time of 0 photometric information transferred to V8n,
In this embodiment, in which SOQ is at "L" level and the AND gate ANI O output is also at "L'" level, clock pulses are supplied to the horizontal and vertical shift registers. Reset F,
It is. When the one-shot circuit N82 generates a one-shot pulse in synchronization with the falling edge of the MH pulse at time tsK, RP5 is reset and IC! G is 41
Ha'' level is inverted, the reset of the counter CNI is also released, and at time t4t, the clock pulse Vφ plate, v is output, and the photometric information transferred to the vertical shift register is transferred to the horizontal shift register H8, each 4''zltk@+Ylg
”・2 Bn-1+ Yn-t, stored as photometric information of Mn+Zn.
When a full count carry occurs from the C terminal, the DPI is inverted, so a p-tsuk pulse Hφ1°H6 is output until time t@, and An+Zn, Bn-t are output in 1 time series.
+Yn-t.

..., A, +Y, , Mus"Zt O information is output to the VF via the charge voltage conversion circuit. The output photometric information is subjected to real-time calculation processing in the photometric calculation circuit, and corresponds to the subject brightness. An accumulation time setting circuit AD that outputs shutter speed or aperture information, displays it via the photometric information display means MT, and sets the accumulation time for image shooting.
2. If the power switch for photography is not turned on by time t@, the counter CNI [Full Count Carry TC will be output] in synchronization with the end of reading out the camera photometry signal in the embodiment.
Since the DPI is inverted, N8 is synchronized with the falling edge of the DPI.
1, a wrinkle shot pulse is generated, and photometric information is repeatedly stored and read out in the same manner as the operation between times t and t.

To prevent malfunction, the timer circuit TCI keeps the power switch for photography 8W until the floating charge is cleared after so-called 1 is turned on.
In order to suppress the turning on of 2, a "H" signal is output, and 7 RIB 4 TUB RFI, RF is output via OR gate OR8.
3. This is a circuit that resets RF4. R1i'l
is time t! However, it is reset by a one-shot pulse from the NSI that occurs at the same time.

While the output of u5, I■, is at the "L level", the output of AN6 is at the sLa" level, and loss ζ is not set. When Iω is reversed to "H level" at time ts, RF2 is set.

On the other hand, RF3 is a flop that holds the photographic power switch 2 on, and when the power switch is turned on at time 1,
RF3 is set and the output of AN7 is inverted to "H'" level, so the photometry information is 01! RF4 due to the one-shot pulse generated from N81 at the time when the extraction is completed.
is set, the Q terminal becomes ``L'' level, the output of ANl is inverted to ``L0'' level, and the clock pulse controlled by AN2 to AN5 is cut off.After RF4 is driven by the output of N81, DT outputs RF2. This is a minute time delay circuit that allows the MH pulse to be driven.At time 1, when a one-shot pulse is generated from N82 in synchronization with the falling edge of the MH pulse, RF6 is set, so the timer circuit TC2 counts time.

When repeating photometry without SW2 being turned on, 'rC2' is activated by the next pulse from N81.

RF6 and RF7 are reset, but when the irrigation is on, the output of AN7C) is at "H0 level", so the first input of AN9 is "L'" through the inverter, so for example, at time -, a pulse is generated from N81. Even if this occurs, it will not be reset because the output company of AN9 is "L level". When the time from the start of accumulation of photometric information to the start of accumulation of image shooting information reaches 50 seconds, the output of timer circuit TC2 is inverted to ``H level''. Shot pulse occurs, RF8 is set,
The ICG is inverted to the s I, a level and accumulation of photographic information is started.

On the other hand, since the Q terminal of RF7 remains at the "H'" level, the clock pulse φ1 is input to the CK terminal of the counter CN3 via AN12 and is counted. The CN30 count signal is compared with the information AD2 from the photometry calculation circuit CMI and the tomagraph comparator MC2f, and if they match, it becomes 8H.
A pulse is generated and the accumulation of image information corresponding to the subject is completed at time - ◎The nine image information accumulated in all the photoelectric conversion elements corresponds to the SH pulse, and the charge is transferred (FA~).

..., FAn;...i FZ, ,...,
Image direct shift register v81 through li”Zll...
・, VSnK transfer. SH pulse is OR5, ANI
'A generates a pulse synchronized with φ, pulse, furthermore KOR6 generates a wrinkle pulse from N84, synchronized with φ, O inversion pulse and ANI4 'V'16
produces t. Also, in synchronization with the falling edge of the ANI4 output, N
A one-shot pulse is generated from 85, and ANI5 synchronizes with the φ1 recirculation and outputs Vφ via OR7. RF9 is set by the output of system N150, and φ breaths are counted at the CK terminal of counter CN4 via ANI6. Hφt e while ☆Untbals is in CN4
H4M occurs and image information is read out. Reading of image information 0 for one line is completed. b and CN40 'l' C
A full count carry is generated from the terminal, and when the count is reset, KVφI t Vφ and Hφt-H#m ”IN are sent through yc OSs and OR6 as before.
0 lines below the occurrence vI! Extrusion is carried out. The counter CNS counts through the CK terminal the output end pulse of each row generated by the C1IIa terminal, and when the reading of all image information is completed, a pulse is generated at the C terminal and a one-shot pulse is output via the N86. Occurs, counters CN5, RF6, Te3.8F and or gate O assistant cRFi, RFs, RF+t 947
) 1. , h Start new photometry 0 seconds or 50 milliseconds Since it is set to 0 integer times, flicker errors in photometry information and shooting information are removed from the AC power supply drive light t[K, and a stable image is always obtained. #! Obtain shooting information,
0

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of a method for removing 7 Ritzker errors according to the present invention, FIG. 2 is a diagram showing an example of a photographing element suitable for the present invention, and 3rd WA is a diagram showing a specific example of a method for eliminating fritzker errors according to the present invention. FIG. 4 is a diagram showing an example of the circuit of the same circuit.0H8...Horizontal shift register v8. ~V8m・・・Vertical shift register input, ~
An, ..., z嘗～Zs... Light receiving section FA, ...
FAn, . . . , FZ, ~FZa . . . Charge transfer gate MA1. MAn, -, Mzl, MZn
・−・・−Transfer for photometry! lFF applicant Canon Co., Ltd.

Claims (1)

[Claims] In a solid-state imaging device that stores photometric information corresponding to subject brightness fK in a solid-state imaging device and stores one-image shooting information O based on 0-wrinkle photometric information, the interval between the storage of the photometric information and the storage of image shooting information is It has a photometry function that eliminates flicker errors in photometry information and image shooting information due to fluctuations in the amount of light of the subject irradiated by the AC power-driven light source by setting the time to an integral multiple of 50 milliseconds. 7 power prevention methods for solid-state imaging devices.