JPS604378A - Image pickup device - Google Patents

Abstract

PURPOSE:To effectively remove a smear phenomenon, by reading out line information in the vicinity of the boundary between a photoelectrically converting section and an accumulating section and calculating the line information and another line information read out from the accumulating section. CONSTITUTION:Electric charge accumulated in a photoelectrically converting section are shifted to an electric charge accumulating section in a vertical blanking period. All image information in the charge accumulating section is successively read out by a horizontal register and smear components are read out in 1-H period just before the next vertical blanking period. Only the smear components read out in the 1-H period are AD-converted and stored in a line memory 24 for a period of 1-V period. The smear components are attenuated by an attenuator 26 after they are again DA-converted and become smear correcting signals 29. When the smear correcting signals 29 and picture signals are supplied to a subtracting circuit and their difference is obtained, a picture signal 28 in which smear components are removed, are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an imaging device using a frame transfer type COD, and particularly to an imaging device that eliminates a smear phenomenon.

(Prior art) In the case of a conventional frame transfer type CCD, as shown in FIG. When a part of the conversion unit 1 is irradiated with strong light, a charge proportional to the level of this light is generated, and when the charge in the storage unit 2 is read out via the horizontal register 6 and amplifier 7, that part is displayed on the screen. A phenomenon occurs in which the screen appears to be slightly raised from the top to the bottom compared to other parts, which greatly deteriorates the quality of the screen.

Conventionally, no method or device has been devised to effectively eliminate such a so-called smear phenomenon.

(Objective) It is an object of the present invention to provide an imaging device that eliminates the drawbacks of the above-mentioned conventional example and is capable of obtaining smear-free image gaps.

(Example) The present invention will be explained below based on Examples.

2 to 5 are diagrams illustrating the first embodiment of the present invention. In FIG. 2, the same numbers as in FIG. 1 indicate the same elements. a to C are photoelectric conversion , d - g are pixels of the storage section, and the storage section 2 has one horizontal line more than the photoelectric conversion section 1, and the anti-blooming drain 9 is located near the boundary with the photoelectric conversion section in the storage section 2. 103 is a light shielding film.

FIG. 5 is a diagram showing an example of the configuration of an imaging apparatus according to the present invention, in which 20 is a CCD as shown in the second diagram, 21 is a CCD drive circuit, 22 is a control clock generation circuit, 26 is a converter,
24 is a line memory as a storage means, 25 is a V person converter, 26 is an attenuator, and 27 is a subtraction circuit as arithmetic means.

FIG. 4 shows a CC driven by the drive circuit 21 in FIG.
It is a diagram showing an example of the internal potential state of D.
The figure is a diagram showing drive timing by the drive circuit 21.

The operation of this embodiment will be explained below using FIGS. 2 to 5.

In order to simplify the explanation, the present invention will be explained in detail using a single-phase driven frame transfer type CCD as illustrated in the schematic potential diagram of FIG. Note that FIG. 3 shows pixels C to f near the boundary between the photoelectric conversion section and the storage section. In a single-phase drive CCU, as shown in FIG. 6, the poten- tial is fixed as a fixed poten- tial 16 in the portion not covered by the transfer electrode 101 of the photoelectric conversion section and the transfer electrode 102 of the storage section, and the electrode In the portions below electrodes 101 and 102, when the clock voltage is at a high level, the voltages below the electrodes 101 and 102 are at a voltage level of 12, and when the clock voltage is at a low level, the voltage level is at a voltage level of 11.

Therefore, when pulses ψPI and ψps of the same phase and amplitude are supplied to the electrodes 101 and 102, charges are sequentially transferred rightward in FIG.

Now, for the CCD of FIG. 2, the drive circuit 21 of FIG. 6 sends the drive pulse (a) of FIG. 4 to the photoelectric conversion unit 1, and the pulse (
b) is applied to the storage section 2, and pulse (c) is applied to each transfer electrode of the horizontal register 6. Thereby, the image stored in the photoelectric conversion unit 1 is transferred to the charge storage unit 2 during the vertical blanking period T2. Furthermore, during period T3, while keeping the drive pulse (b) at a high level, the contents of the photoelectric conversion section are transferred several horizontal lines by the drive pulse (,), thereby transferring the contents of the photoelectric conversion section several horizontal lines to the first line d of the charge storage section 2. smear components are added and accumulated.

Next, when all the image information in the charge storage section 2 is sequentially read out from the horizontal register 6 during the period T5, the smear component is read out from the horizontal shift register 6 during the 1H period T6 immediately before the next vertical blanking period.

In this way, the smear component generated in the period T6 immediately before the vertical blanking period is transmitted only during the period T6 to the Φ converter 2.
The width is converted by 4.5 and stored in the line memory 24 for a period of 1V. After being D/A converted by the converter 25, it is attenuated by the attenuator 26, and becomes the smear correction signal 29. The attenuation rate by the attenuator 26 is 1 for the number n of blank stares to detect the smear component.
/n, so the smear correction signal 29 and the smear component included in one line of the image are approximately the same amount,
When the subtraction circuit 27 takes the difference between the smear correction signal 29 and the image signal, the smear component is canceled out, and a smear-free image signal 28 can be obtained. Note that here, the smear correction signal 29 is the average value of the smear components of n lines, so S
It is possible to improve Ha by F times.

In addition, during the period T3 etc., a part is exposed to very strong light, and the smear component accumulated in the charge accumulation section 2 is removed from the charge accumulation section 2.
Even if the saturation capacity of the cell exceeds the saturation capacity of the cell, the excess charge is disposed of to the anti-blooming drain 9, so no blooming occurs.

Further, in this embodiment, the case where the number of horizontal lines of the storage section 2 is one more than the number of horizontal lines of the photoelectric conversion section has been described, but the number may be the same. In that case, the number of horizontal lines actually reproduced on the motor can be eliminated.

In Figures 6 to 8, a horizontal shift register 31 is installed between the photoelectric conversion section 1 and the charge storage section 2 of a 7-frame transfer type CCI), and the smear component is read out from this horizontal shift register 61 during the vertical blanking period. FIG. 3 is a diagram for explaining a second embodiment of the present invention.

In this embodiment, as shown in FIG.
A CCD is used. Details of such a structure can be found in Japanese Patent Application Laid-Open No. 58-48455.

If this second horizontal shift register 61 is driven in the same phase as the optical converter 1 and the charge storage section 2, the charge in the photoelectric conversion section 1 will be transferred to the charge storage section 2 via this register 31.
If a driving pulse is applied only to the horizontal shift register 31 while stopping the clock pulse applied to the photoelectric conversion section 1 and the charge storage section 2, the charge will not be transferred to the charge storage section 2,
It is configured to be read from the second horizontal shift register 61.

FIG. 7 is a diagram showing the circuit configuration of this embodiment.

In the embodiment shown in FIG. 6, all the image information is read out from the horizontal shift register of the body in a certain field and then the smear component is read out, whereas in the second embodiment shown in FIG. register 31
After reading out the smear component from the first horizontal shift register 6, the image signal is read out from the first horizontal shift register 6. Therefore, since a signal of the same field as the image information can be used as the smear correction signal, more accurate smear correction can be performed.

Note that the same numbers as in FIG. 6 indicate the same elements.

40 is a frame transfer type COD having a second shift register as shown in FIG.

Further, 32 is the second shift) register 31 output amplifier 7'.
The A/D converter 26 inputs the output 66 of this amplifier 32 and digitizes it.

Further, 211 is a drive circuit for driving the CCD, which outputs output pulses as shown in FIG.

In FIG. 8, (d) shows the pulse ψP applied to the photoelectric conversion unit 1.

(e) is the pulse ψS11 applied to the second horizontal shift register 61 (f) is the pulse ψps applied to the charge storage section 2
.

(g) is the pulse ψ applied to the first horizontal shift register 6
It is S2. The drive circuit 211 transfers the charges stored in the photoelectric conversion section 1 to the charge storage section 2 during the period T1o. Next, in period T20, the smear component is added and accumulated in the second horizontal shift register 61 of the photoelectric conversion unit 1. Next, in period 'E'30, the aforementioned smear component is read out from the second horizontal shift register and stored in the line memory 24, for example.

Next, in period T40, the image information stored in the charge storage section 2 is continuously outputted from the horizontal shift register b.

In this way, according to this embodiment, the smear component during and immediately after the vertical transfer of the charge accumulated in the photoelectric conversion section 1 to the accumulation section 2 can be calculated as the readout output from the accumulation section, so that smear can be removed more reliably. I can do it.

(Effects) According to the present invention, smear-free images can be obtained extremely easily.

[Brief explanation of drawings]

Figure 1 shows the origin of frame transfer CCD. FIG. 2 is a configuration diagram of a frame transfer CCD according to the present invention, FIG. 6 is a diagram of a first embodiment of the present invention, and FIG. 4 is a diagram of a CCD.
5 is a timing diagram of the first embodiment of the present invention, FIG. 6 is a configuration diagram of a CCD according to the second embodiment of the present invention, and FIG. 7 is a diagram showing the potential state under the electrode. FIG. 2 is a circuit configuration diagram of the second embodiment. FIG. 8 is a timing diagram of a second embodiment of the present invention. 1 is a photoelectric conversion unit, 2 is a charge storage unit, 6 is a horizontal shift register, 7 is an output amplifier, 9 is an anti-pluming drain, 20 is a CCU, 21 is a drive circuit, 22 is a control circuit,
25 is a central transducer, 24 is a line memory, and 25 is a D/
A converter, 26 is an attenuator, and 31 is a second horizontal shift register.

Claims (1)

[Claims] A frame transfer type CCD. storage means for reading and storing line information near the boundary between the photoelectric conversion section and the storage section of the CCD; An imaging device comprising a calculation means for calculating line information read from the storage section and line information stored in the storage means.