JPS5839183A - Flash photographing system for solid-state image pickup device - Google Patents

Abstract

PURPOSE:To obtain a well-balanced and high-quality image even if the sensitivity to, for example, blue is degraded in a solid-state image pickup element, by controlling the light emission quantity of a flash device for each color on a basis of characteristics of the solid-state image pickup element and a color separating filter. CONSTITUTION:When a power supply switch 2 is closed, a boosting circuit 3 is operated by a power supply battery 1, and a capacitor 4 is charged to a volage sufficient for flash photography. Red, green, and blue synchronizing signals for an image are applied to terminals (a)-(c) from a solid-state image pickup device and are applied to the gate of an SCR 6 for trigger of a flash discharge tube 10 through diodes 38-40, and the flash discharge tube 10 emits the light. When the flash light emission is started, the reflected light from an object is detected by a photodiode 27, and an integral capacitor 28 is charged to a prescribed voltage to make an SCR 18 conductive through a comparator 20, and the flash is stopped. The reference voltage of the comparator 20 is made different among red, green, and blue to control the light emission quantity in accordance with each color.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flash photography method for a solid-state imaging device.

Conventionally, when performing flash photography using a solid-state image sensor,
A method has been proposed in which flash light is emitted during the storage time of the image information of the solid-state image sensor, but it is possible to sequentially arrange filters of different colors in front of the solid-state image sensor to capture color-separated objects. When performing flash photography with a solid-state imaging device that stores corresponding image information, there is a problem in that it is not possible to obtain color-separated TRR* information with good color balance.

- The present invention provides a method for obtaining high-quality color-separated flash photography image information.The present invention will be specifically explained below using the drawings.

FIG. 1 shows an embodiment of a solid-state image sensor for realizing the present invention. .

aml + ・= −@ 11jL凰: ”・”・:
sit @ ---・+ BKm is a charge storage section consisting of a photoelectric conversion section such as a photodiode, and a charge storage section for accumulating image information corresponding to the subject, GAI, -----, Gm*;
”---; Gtrl, ...-, GU* is a multi-column (D shift) cashier X # v4 vn, tony; vl
, V.G.

A charge transfer gate for transferring the charge accumulated in the charge storage section 8m to vl = 8Km, and a control terminal 8H
1., 8112, 8113. Multiple columns of vertical shift) registers each have a vertical shift pulse VFI.
vsz It is driven sequentially from town call to town call.

The information on both images transferred via these vertical shift registers enters the horizontal shift register H8 and is transferred to the horizontal shift register H8. The signal is sequentially transferred in the horizontal direction by Bφ2, converted into voltage information via a charge potential conversion circuit including a length effect transistor Fl and an IF2 resistor 11, and outputted as video information v1. This charge voltage conversion circuit is φ
Each time the image information of each picture element is read out via the l terminal,

Further, the XOa terminal is a terminal for clearing the image information accumulated in each pixel to the power supply Vcc as necessary.

FIG. 2 shows an example of a color separation filter suitable for the present invention, such as R (red) and B (blue).

The image information of the subject is color separated into G (green).

MuR1, MuR2, MuGl, AG2. M Bl and M B2 are holes for color discrimination and image information storage start signal SR1,
8G1.811 is a hole for a color filter switching or image information accumulation completion signal, and these holes are detected by photocoupler POI and PO2. POI, I'0
The unitary imaging element of the 1st vA structure is driven by the pulse of the timing chart shown in FIG. 3, which is generated based on the signal detected at step 2.

FIG. 4 is a diagram illustrating one embodiment of the electrical circuit that generates the pulses of FIG. 3.

R1-R7 are resistors, 01 is capacitors, MUN1-MUN7
is AND gate, ORI, OR2 is OR gate, R
FI is an R-87 lip with 70 tubes, DFI is DFI, DF2 is a D gate, ONT is a match counter, Lll to L13 are light emitting diodes, and phototransistors! r1~T
A photocoupler is constructed with r3. Tr4 to Tr6 are transistors, 1 is a power supply battery, and 8W1 is an imaging switch.

IC0D is an encoder, and in response to the input of Qi + Qz, any terminal of D1 to D4 is at high level])1
; When (0, 1), I) 2; When (1, 0), D3;
(0,0), D4 is selected and inverted to high level. When the imaging switch 8W1 is turned on at time t1 in Fig. 3, o
The power-up clear circuit consisting of L and R initially clears the 7p and 7p blocks, and the color discrimination signal detection circuit starts operating. Here, it first detects that the red filter is applied to the image sensor 8F. .

When the PCI detects the mu wound R2 at time t,
.

'1't4〼Tr2. ? r5 is turned on and Pmu1. The Pmu2 terminal becomes high level, and the q output of the blade ν1 is inverted to a high pull level via the MuN1, and the IOG is inverted to a low level, and the accumulation of red image information is started at 8P.

When F02 detects 8Bl at gts, Tr3. 〒r
6 is turned on and 781 becomes high level, a pulse is supplied to the terminal via 5N3, and the red image information is temporarily transferred to the superposed shift registers V, -, and VB.

After the charge transfer, in this figure, ONI generates a one-shot pulse in synchronization with the falling edge of F81, and DPI is inverted via ORI and M2 in synchronization with the rising edge of the pulse, so I
OG flips to high level and residual charge is cleared. When POI detects MuGl and MuG2 at time Lu4, Dem1 becomes low level and Pmu2 becomes high level, so FiXl
, 5A pulse is supplied to 81f2 via N4, and the charges accumulated in the vertical shift register MA, -, Vl become ■,
-, v'l' and OR1°5N2. D
IOG is flipped to a low level via PI and the accumulation of green image information begins. Furthermore, Dff2 is also inverted by the pulse supplied to 8H2.

When PO2 detects 801 at time ts, F81 becomes high level and Al1. Via 5N5! IHI, 81
A pulse is supplied to 13, and the green image information is transferred to the vertical shift registers Vm, . . . , VB, and VB, .
·, The charges stored in VG are transferred to the vertical shift registers yc-, yc.

When POI detects MuBl and MuB2 at time t1, P
Since M1 is a high level and Pm2 is a low level, ICXI
.

A pulse is supplied to SR2 through N4 and the voltage is 1v^°°°
.

The charge accumulated in v8 is i/B, -., V? At the same time as being transferred to OBL, Mu N2. IO via DPI
G is inverted to a low level and the accumulation of blue image information begins. Further, Dv2 is also inverted.

When PO2 detects 8B1 at time 7, P81 becomes high level, so a pulse is supplied to 8E1 via MuN3, and the blue image information is transferred to the vertical shift register rim, -1vs.
Transferred to I. Counter ONT is set to IH via INl.
A pulse is generated that counts the falling edge of the I pulse, and the OR
Since the RFI is reset via 2, the Q output of the RFI is inverted to a low level in synchronization with the falling edge of the 8B1 pulse that occurs at time jlty, and subsequent capture of image information is prohibited. In other words, time t.

Between t10 and t10, red, green, and blue (m, :e, o) image information is stored in a number of vertical shift registers. ..., VU;vn
,-, Ma! :Vum, -, vs are stored. These accumulated image information of each color are vertical drive pulse Vφ1+Vφ*−horizontal m motion pulse Rφ1Bφ after time t7.

Accordingly, heavy, ), and G signals are output in sequence.

FIG. 5 is a circuit diagram showing an example of a flash device according to the present invention applied to the above-mentioned imaging device. In the figure, 1 is a power supply, 2 is a main switch, 3 is a booster circuit, 4 is a main capacitor, 6,
11 and 18 are 80B, 8.14゜16.28 is a capacitor, '5.12.13.17.19.23~263
0, 41.42 are resistors, 32 to 34. 38 to 40 are diodes, 9 is a transformer, 10 is a discharge tube, 20 is a comparator, 21.22.29.31 is a transistor,
27 is a light receiving element, and 35 to 37 are monostable multivibrators.

5th v! When the power switch is closed at J, a known booster circuit 3 is activated by the power source battery 1, and the main capacitor 4 is charged to a voltage sufficient for performing flash photography. Similarly, the commutation capacitor 14 is charged by the booster circuit via the resistor 17.13.
When 1 and 12 are detected, Qt of l0I) becomes 1.1, and 1) 1 becomes 1. When a synchronizing signal for, for example, a red image is given to terminal a from the solid-state imaging device, this signal is passed through the diode 38. is applied to the gate of trigger B016 of flash discharge tube 1o through 80B, which becomes conductive.

Along with this, the synchronization signal is applied to the input of a known monostable multivibrator 35, and the multivibrator 35
The output of the transistor 31 is shifted from a low level to a high level, and the high level output is applied to the base of the transistor 31 via the diode 32 to turn the transistor on, and the resistor 4
Similarly, the transistor 21 is turned on via the transistor 1.

Due to the conduction of the GCNS, a known flash discharge tube trigger circuit composed of a trigger capacitor 8, a trigger transformer 9, and a resistor 5 is activated, and a high frequency high voltage is applied to the trigger electrode of the flash discharge tube 10. 1G is ionized.

This ionization causes the main capacitor to pass through the flash discharge tube 10. Commutation capacitor 14, capacitor 16, resistor 15, main 5ORII 17) ke'-) -ka-
An ionizing current flows through the main capacitor 8 (7R11) and becomes conductive. Due to this conduction, the charge in the main capacitor 4 is discharged through the flash discharge tube 10.main 80R11, and flash light emission begins. .At this time, transistor 3
1 is in the ON state as described above, so the transistor 29 is 0! It is in the ν state. Therefore, the integration of the output of the photodiode 27, which has received the reflected light from the flashing subject, is started by the integrating capacitor 28. Further, the voltage at the inverting input of the frequency converter 20 is the voltage divided by the resistor 23 and the resistor 24 since the transistor 21 is in the ON state as described above. As the amount of received light increases, the voltage of the integrating capacitor 28 increases, and when it exceeds the partial voltage Mar, the output of the comparator 20 shifts from a low level to a high level, making the 80R18 conductive. ll0
When R1B becomes conductive, a known flash control circuit consisting of 8(IRII, 18. resistor 12.13, Is, 17, and capacitor 14.16) is activated, and the flash light emission is stopped.

Incidentally, after a predetermined period of time has elapsed since the synchronization signal was applied to the terminal a, the monostable multivibrator 35 returns to the state before the synchronization signal was generated. Further, the flash control operation is performed within this predetermined time.

Next, at time t4, when the POI detects MU Gl and MU G2, Qss Qt of man becomes 0.1 and D2 becomes 1, and when a synchronization signal for, for example, a green image is given from the solid-state imaging device b, the corresponding The signal is applied to the gate of the trigger 80R6 via the diode 39, and at the same time as the 80116 is turned on, it is applied to the known monostable multivibrator 36, and the output of the multivibrator 36 is shifted from a low level to a high level, The run raster 31 is turned on (through the diode 33), and the resistor 4 is also turned on.
The transistor 22 is also turned on via the transistor 2. Above 8
When 0R6 becomes conductive, flash light emission starts as described above.

At this time, as described above, the transistor 29 is in the OFF state, so the output current of the photodiode 27 in response to the light reflected from the flashing subject is transferred to the integrating capacitor 28.
It is integrated at . Further, since the transistor 22 is in the ON state as described above, the inverted input voltage of the humpparator 20 is the divided voltage vo' of the series resistance of the resistor 23 and the resistor 24.25. When the integral capacitor voltage increases as the amount of received light increases and exceeds the partial voltage VO, the comparator 2
The output of 0 is shifted from a low level to a high level and is applied to the gate of 80R1B, and the known flash control circuit is activated to stop the flash. After a predetermined period of time has elapsed since the synchronization signal is applied to the terminal -, the output becomes monostable. The multivibrator 36 returns to the state before the synchronization signal was generated, and the flash control operation is performed within this predetermined time.

Next, when Pol detects MuBl and MuB2 at time t6,
Q1+Qx of 110D becomes 1.0 and D3 becomes 1
When a synchronizing signal for a blue image, for example, is applied to the terminals from the solid-state image sensor, the red and blue signals described above are applied to the terminals a and b.
The flash light emission is started in the same way as when the flash light emission is applied, and the photodiode output corresponding to the reflected light from the subject of the flash light emission is integrated in the integrating capacitor 2i. The inverting input of comparator 2° is resistor 23 and resistor 24, 25, 26
Since the pressure of the integrating capacitor rises and exceeds the voltage division VB, the output of the comparator 20 shifts from a low level to a high level.
80R18 is made conductive, the known control circuit is activated, and the flash is stopped.

After a predetermined period of time has elapsed since the synchronization signal was applied to the terminal C, the monostable multivibrator 37 returns to the state before the synchronization signal was generated, and the flash control operation is performed within this predetermined time. Furthermore, the present invention can also be applied to a solid-state image sensor having a color mosaic filter disposed on the front surface by configuring the device to read out eight pieces of information corresponding to each color separately.

As described above, when the flash photography method of the present invention is used, the amount of light emitted by the flash device is controlled for each color based on the characteristics of the solid-state image sensor and the color separation filter, so for example, blue sensitivity may be slightly reduced. Even if a solid-state image sensing device such as the one shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of an image sensor suitable for the present invention, FIG. 2 is a diagram showing an example of a color separation filter applicable to the present invention, and FIG. 3 is an example of drive timing of the device shown in the first diagram. FIG. 4 is a diagram showing an example of a drive circuit for the element shown in FIG. 1, and FIG. 5 is a diagram showing an example of a flash device suitable for the present invention. 8 people 1-8mmh......, SKI N8 *
: Light receiving section, Vmu~vU: Shift register HR; Horizontal shift register 10: Flash light source 35, 36.37: Monostable multivibrator-27
:Light receiving element. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] A color separation filter is provided in front of the solid-state image sensor, and 1. A flash photography method of a solid-state imaging device characterized by a solid-state that stores image information corresponding to a color-separated subject.