JP2000050165A - Solid-state image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state image pickup device capable of suitably correcting a smear without a side effect due to a random noise or the like to be included in a smear correction pattern. SOLUTION: A line memory 3 for storing a smear pattern is provided to this solid-sate image pickup device, where a signal in a dummy area of the solid-state image pickup device 1 is stored by a writing signal WE of a timing generator 4A. The line memory 3, an adder 8 and a divider 9 are made to function as a low-pass filter. Then, a pixel signal from which the smear is removed is obtained when an output of the divider 9 is subtracted from an output of an A/D converter 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device having a function of removing a smear component from a charge signal output through a vertical transfer register and a horizontal transfer register.

[0002]

2. Description of the Related Art In a solid-state image pickup device widely used at present, signal charges generated by photoelectric conversion elements arranged in a matrix are transferred in a vertical direction using a vertical transfer register, and transferred by a vertical transfer register. The input signal charges are input to a horizontal transfer register and transferred in the horizontal direction, so that pixel signals are read out line-sequentially. When an image of a high-luminance object is captured by such a solid-state imaging device, light leaks into the vertical transfer register during the vertical transfer of signal charges, and the leaked light is photoelectrically converted to generate vertical streak noise. There is a problem that a certain smear occurs.

FIG. 10 is a block diagram showing a configuration example of a conventional solid-state imaging device having a smear correction device for removing the smear. As shown in FIG. 10, the solid-state imaging device includes a solid-state imaging device 1, an A / D converter 2, a line memory 3, a timing generation circuit 4, a subtractor 5, and a drive circuit 7.

As shown in FIG. 2A, the solid-state imaging device 1 includes an imaging unit 41 including a photoelectric conversion unit for photoelectrically converting an image of a subject and a transfer unit for vertically transferring signal charges of the photoelectric conversion unit. The photoelectric conversion element 4 formed around the imaging unit 41
OB area 42 (light-shielded photoelectric conversion unit) that shields light from
Dummy region 43 formed above and below region 42
And a horizontal transfer register (horizontal transfer CCD) 44 for transferring the signal charges generated by the imaging section 41 in the horizontal direction. FIG. 2B is a partially enlarged view of the imaging unit 41. A plurality of photoelectric conversion element arrays 45 a, 45 b,... In which a plurality of photoelectric conversion elements 40 are formed in the column direction, and a vertical transfer register for transferring signal charges generated in the photoelectric conversion element arrays in the vertical direction. (Vertical transfer CCD) 46a, 46b
・ ・

A line memory 3 shown in FIG. 10 is a memory for temporarily storing A / D-converted pixel signals for one line. When a recording signal WE (hereinafter, referred to as a signal WE) is given, a line clock 3 is used as a write clock. Write the input signal synchronously. In addition, it outputs the written signal in synchronization with the read clock. The timing generation circuit 4 supplies a horizontal synchronization signal (HD) and a vertical synchronization signal (VD) to the drive circuit 7.
And a signal WE to the line memory 3 during a specific one line period. Subtractor 5
Is a circuit for subtracting the one-line pixel signal held in the line memory 3 from the one-line pixel signal output from the A / D converter 2. The result of the subtraction by the subtracter 5 is output to the outside via the output terminal 6.

The operation of the solid-state imaging device having such a configuration will be described. As shown in FIG. 2, an image of a subject is formed on the imaging unit 41 in which the photoelectric conversion elements 40 are arranged in a matrix. The signal charges generated in the respective photoelectric conversion element arrays 45 are read out by the vertical transfer CCD 46 and then transferred in the vertical direction. And each vertical transfer CCD 46a, 46
are output to the horizontal transfer CCD 44 line by line.

[0007] As shown in FIG.
0 exists in the imaging unit 41 and the OB area 42. In the dummy area 43, there is a vertical transfer CCD 46 without a corresponding photoelectric conversion element. Including these areas, the vertical transfer CCD 46 sequentially transfers electric charges at a constant speed in the vertical direction. Then, pixel signals are output from the horizontal transfer CCD 44 line-sequentially including the area other than the imaging section 41. By repeating this, a moving image signal is obtained.

When the subject has a very bright portion, light may leak into the vertical transfer CCD 46 in some cases.
In this case, vertical streak-like noise, that is, smear occurs. If the charge transfer speed in the vertical transfer CCD 46 is constant and the subject does not move significantly, smear occurs at a constant level in one column of the vertical transfer CCD 46.
Here, the OB area 42 above and below the imaging surface or the dummy area 4
Since there is no signal charge due to the subject on the vertical transfer CCD 46 corresponding to No. 3, only a smear component is generated. Therefore, by subtracting the signal of the OB area 42 or the dummy area 43 at the top and bottom of the screen from the output signal of the solid-state imaging device 1, a pixel signal from which smear has been removed can be obtained.

FIG. 11 is a time chart schematically showing waveforms of output signals from the solid-state imaging device 1 and the timing generation circuit 4 in the solid-state imaging device shown in FIG. FIG.
In synchronization with the vertical synchronization signal (VD) shown in (a) and the horizontal synchronization signal (HD) shown in (b), a pixel signal is output from the solid-state imaging device 1 as shown in (c). As shown in FIG. 11D, the signal WE of the timing generation circuit 4 becomes H level only for one line period corresponding to the dummy area 43 of the solid-state imaging device 1. The line memory 3 in FIG.
Is only at the H level, the pixel signal output via the A / D converter 2 is stored. In this way, of the output signals of the solid-state imaging device 1, an output signal corresponding to the dummy area 43 is held in the line memory 3 as a so-called dummy signal. The dummy signal held in the line memory 3 is read out for each line, and is subtracted from the pixel signal of the image sensor 1 by the subtractor 5. With the above operation, a pixel signal from which smear has been removed can be obtained from the output terminal 6.

[0010]

However, in the above-described conventional solid-state imaging device, the OB area 42 or the dummy area 4
In order to always subtract the signal of one line of 3 from the whole screen,
When an unnecessary signal other than smear, that is, dark current, random noise, or the like is mixed in the signal of the OB area 42 or the dummy area 43, even when smear does not occur in the solid-state imaging device 1, vertical streak-like noise occurs. There is a problem that there is a side effect (first problem).

When the subject is moving, that is, when the position of the light source moves during the transfer of the signal charges in the vertical transfer CCD 46, the smear may not be completely vertical. Even in such a case, if the signal of the line memory 3 is subtracted from the pixel signals of the entire screen,
There was a problem that an incorrect correction was made (second problem).

Further, when the output level of the pixel signal of the solid-state imaging device 1 is already saturated, if the signal of the line memory 3 is subtracted from this pixel signal, a bright portion which should be originally saturated will be lost. There is a problem that the image looks dark (third problem).

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and solves the above-mentioned first to third problems, and provides a solid-state image pickup device which can perform favorable smear correction with few side effects. It is intended to be realized.

[0014]

According to a first aspect of the present invention, there is provided a photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix to photoelectrically convert imaging light of a subject, and a plurality of lines of photoelectric conversion elements are shielded from light. A light-shielded photoelectric conversion unit, a vertical transfer register unit for vertically transferring image pickup charges from the photoelectric conversion unit and the light-shielded photoelectric conversion unit, and a line-sequentially transferring image charges vertically transferred from the vertical transfer register unit. A solid-state imaging device that uses a solid-state imaging device having a horizontal transfer register unit to transfer and removes signal components other than pixel light of a subject from pixel signals output through the vertical transfer register unit and the horizontal transfer register unit. A line memory for storing, among output signals of the solid-state imaging device, dummy signals generated from a plurality of lines located in the light-shielded photoelectric conversion unit; Averaging means for averaging a plurality of lines of dummy signals located in the light-shielded photoelectric conversion unit using a signal held in a memory, and subtracting an output signal of the averaging means from an output signal of the solid-state imaging device. And subtracting means for performing the subtraction.

According to a second aspect of the present invention, in the solid-state imaging device according to the first aspect, the line memory accumulates and stores a dummy signal of the same field generated by the light-shielded photoelectric conversion unit for each line, And outputting a cumulative addition value of the dummy signal.

According to a third aspect of the present invention, there is provided a photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix and photoelectrically converts image pickup light of a subject, a light-shielded photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded from light, A vertical transfer register unit for vertically transferring the imaging charge from the photoelectric conversion unit and the light-shielding photoelectric conversion unit, and a horizontal transfer register unit for horizontally transferring the imaging charge vertically transferred from the vertical transfer register unit in the line direction A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, using a solid-state imaging device having: A line memory that stores a dummy signal generated from a line located in the light-shielded photoelectric conversion unit, among output signals of the solid-state imaging device; OB area storage means for storing a dummy signal at the left end or right end of the IN, first subtraction means for subtracting the output signal of the OB area storage means from the output signal of the solid-state imaging device, and the first subtraction means Level monitoring means for monitoring whether the level of the output signal is less than or greater than a threshold,
When the signal level is equal to or higher than the threshold value in the monitoring result of the level monitoring unit, the signal of the line memory is output,
When the monitoring result is less than the threshold value, there is provided switching means for outputting a 0 signal, and second subtraction means for subtracting the output signal of the switching means from the output signal of the solid-state imaging device. Things.

According to a fourth aspect of the present invention, in the solid-state imaging device according to the third aspect, the level monitoring means includes a dummy signal at a left end or a right end of a line located in the light-shielded photoelectric conversion unit and a left end or a right end of the line. The level is compared with a dummy signal other than the dummy signal, and a monitoring result is output.

According to a fifth aspect of the present invention, there is provided a photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix and photoelectrically converts imaging light of a subject, a light-shielded photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded from light, A vertical transfer register unit for vertically transferring the imaging charge from the photoelectric conversion unit and the light-shielding photoelectric conversion unit, and a horizontal transfer register unit for horizontally transferring the imaging charge vertically transferred from the vertical transfer register unit in the line direction A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, using a solid-state imaging device having: Among the output signals of the solid-state imaging device, a line memory that stores a dummy signal generated from a line located in the light-shielded photoelectric conversion unit, and a line memory that is held in the line memory. Motion detecting means for detecting the presence or absence of motion of a subject based on a difference value between a dummy signal of a fixed field and an output signal of the solid-state imaging device in a field following the specific field; and the motion detecting means detects that there is motion. A switching means for outputting a signal in the case of 0 and outputting a signal of the line memory when detecting no motion, and a subtracting means for subtracting an output signal of the switching means from an output signal of the solid-state imaging device. It is characterized by having.

According to a sixth aspect of the present invention, in the solid-state imaging device according to the fifth aspect, the motion detecting means compares a dummy signal of the same light-shielding line between different feeds, and determines that the difference between the fields is equal to or greater than a predetermined value. If so, it is determined that the subject has movement.

According to a seventh aspect of the present invention, there is provided a photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix and photoelectrically converts image pickup light of a subject, a light-shielded photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded from light, A vertical transfer register unit for vertically transferring the imaging charge from the photoelectric conversion unit and the light-shielding photoelectric conversion unit, and a horizontal transfer register unit for horizontally transferring the imaging charge vertically transferred from the vertical transfer register unit in the line direction A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, using a solid-state imaging device having: A line memory for storing a dummy signal generated from a line located in the light-shielded photoelectric conversion unit, among output signals of the solid-state imaging device, and an output level of the solid-state imaging device A coefficient generator for generating a coefficient that becomes smaller than a predetermined value when the coefficient increases, a multiplier for multiplying an output of the coefficient generator by an output of the line memory, and an output of the multiplier from an output signal of the solid-state imaging device. And subtracting means for subtracting

According to an eighth aspect of the present invention, in the solid-state imaging device of the seventh aspect, the coefficient generating means sets a and b to a <b.
b, a coefficient 1 is output when the pixel value x output from the line memory satisfies 0 ≦ x <a, and the pixel value x
Outputs a coefficient (x−b) / (ab) when a <x ≦ b, and outputs a coefficient 0 when b <x.

[0022]

(Embodiment 1) A solid-state imaging device according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a configuration of the solid-state imaging device according to the present embodiment. In this solid-state imaging device, as in the case of FIG.
An A / D converter 2, a line memory 3, a timing generation circuit 4A, a subtractor 5, and a drive circuit 7 are provided. In addition to these, the solid-state imaging device is provided with an adder 8, a divider 9, and a switch 10 to add a function of a low-pass filter and solve the first problem. Note that the blocks with the same reference numerals as those in the conventional example have the same configuration and function, and thus description thereof will be omitted.

In FIG. 1, the adder 8 is an A / D converter 2
And the pixel signal held in the line memory 3, that is, the dummy signal, is added. The pixel signal is added so as to correspond to each pixel position in the same row of the photoelectric conversion element 40. The switch 10 supplies the output signal of the adder 8 to the line memory 3 when the signal SW of the timing generation circuit 4A is at L level, and clamps the input terminal of the line memory 3 to 0 when the signal SW is at H level. It is. The divider 9 is an averaging means for converting the signal level read from the line memory 3 into 1/2.
The subtracter 5 is a subtraction unit that subtracts the output signal of the divider 9 from the pixel signal output from the A / D converter 2, and the subtraction result is output via the output terminal 6.

FIG. 3 is an explanatory diagram showing the operation of the solid-state imaging device according to the present embodiment, and is a schematic diagram showing an output signal of the solid-state imaging device 1 and an output signal waveform of the timing generation circuit 4A. Incidentally, in the signal shown in FIG.
The spike-like pulse is a smear signal. Hereinafter, the operation of the solid-state imaging device will be described with reference to FIGS. FIG.
In the 1H period immediately after the rise of the vertical synchronization signal (VD) shown in (a), both the output signals WE and SW of the timing generation circuit 4A become H level. This state is shown in FIG.
(E). When the signal SW becomes H level, the switch 10 is connected to the broken line side, and a signal of amplitude 0 is recorded in the line memory 3. During the subsequent 2H period, the signal WE is kept at the H level and the signal SW is kept at the L level, and a signal corresponding to the dummy area 43 is output from the solid-state imaging device 1. As a result, the signals of two lines in the dummy area 43 are added by the adder 8 and recorded in the line memory 3. Thereafter, the signal held in the line memory 3 is read out for each line and supplied to the divider 9. The divider 9 divides the input signal by 2, and averages the signals in the dummy area to generate a dummy signal. The subtracter 5 subtracts the dummy signal from the pixel signal of the solid-state imaging device 1 and outputs a pixel signal from which smear has been removed from the output terminal 6.

By the above operation, a pixel signal from which smear has been removed is obtained. In this case, the solid-state imaging device 1
Is a signal subjected to low-pass filtering in the vertical direction, and is a signal in which random noise components are suppressed. Therefore, smear correction with less side effects due to random noise can be performed. According to the configuration of FIG. 1, the line memory for recording the smear signal and the line memory used for the vertical low-pass filter are shared, so that the number of circuits can be minimized. Although the present embodiment has been described on the assumption that the average value of signals corresponding to the dummy area 43 of two lines is used, the average value of signals of three or more lines may be used. As the number of lines increases, the effect of suppressing random noise increases, and the function of a vertical low-pass filter is achieved.

(Embodiment 2) A solid-state imaging device according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 4 is a block diagram illustrating a configuration of the solid-state imaging device according to the present embodiment. This solid-state imaging device has a structure shown in FIG.
As in the case of 0, an A / D converter 2, a line memory 3, a timing generation circuit 4B, a subtractor 5, and a drive circuit 7 are provided for the solid-state imaging device 1. In addition to these, the solid-state imaging device includes a first D flip-flop (D-
FF) 21, subtractor 22, comparator 23, constant generator 2
4, an AND gate 25, an OR gate 26, a second D flip-flop 27, and a changeover switch 28 are provided so that a processing method of a pixel signal is changed depending on whether smear occurs. Note that the blocks with the same reference numerals as those in the conventional example have the same configuration and functions as those in FIG.

The timing generation circuit 4B is similar to that of the first embodiment.
In the same manner as the above, the vertical synchronizing signal (V
D), outputs a horizontal synchronizing signal (HD),
And outputs a signal WE. Furthermore, the first D-FF 21
, And outputs a reset signal R to the second D-FF 27. This load signal L is output when scanning the right or left end of the OB area 42 or the dummy area 43 in FIG.
When the load signal L is input, the D-FF 21 outputs the A / D converter 2
OB area storage means for latching the output signal of The subtracter 22 calculates the D-FF 21 from the output signal of the A / D converter 2.
Is a first subtraction means for subtracting the signal held in the first subtraction means. The comparator 23 has an output level B of the subtractor 22 and a constant generator 2
4 is compared with a constant A, and if B> A, an H level is output.
If B ≦ A, the circuit outputs an L level. When the signal WE of the timing generation circuit 4B is at the H level, the AND gate 25 uses the output of the comparator 23 as a set signal and performs
This is a gate provided to the D-FF 27 via the gate 26. The D-FF 27 is a flip-flop that is set by the output of the OR gate 26 and reset by the signal R of the timing generation circuit 4B. The changeover switch 28 is a D-FF
When the Q output of the switch 27 is at the H level, the signal of the line memory 3 is supplied to the subtractor 5, and when the D-FF 27 is at the L level, the switch for clamping the subtraction input terminal of the subtractor 5 to 0 is provided. The subtracter 5 subtracts the output signal of the changeover switch 28 from the output signal of the A / D converter 2 and outputs the subtraction result to the output terminal 6.
And a second subtraction means for outputting the result via

Here, comparator 23, constant generator 24, AN
The D gate 25, the OR gate 26, and the D-FF 27
Has a function of a level monitoring means for monitoring whether the level of the output signal of the subtraction means is less than or greater than a threshold value.

The operation of the solid-state imaging device having such a configuration will be described with reference to FIG. At the timing when the solid-state imaging device 1 outputs the dummy line, a load pulse L is output from the timing generation circuit 4B to the load terminal of the D-FF 21 as shown in FIG. At this time, if any signal is generated at the head of the dummy line of the solid-state imaging device 1, that is, at the right end of the dummy area 43, the signal is stored in the D-FF 21. The right or left end of the dummy area 43 does not have the photoelectric conversion element 40 and the vertical transfer CCD 46 is optically shielded, so that no smear occurs. That is, the signal generated in this region is noise having a DC component such as a dark current.

Next, as shown in FIG. 5D, a reset signal R is sent from the timing generation circuit 4B to the D-FF 27.
Is output, the D-FF 27 is reset, and the Q output becomes L level. Therefore, the changeover switch 28 is switched to the broken line side. On the other hand, the subtractor 9 is used to
Is subtracted from the output of the D-FF 21 to output a signal difference value. This difference value is a signal from which a DC component due to a dark current or the like is removed and only a smear component is detected. This difference value is input to the comparator 23 and compared with a constant A. As shown in FIG. 5D, the signal WE of the timing generation circuit 4B is at the H level during the scanning of the dummy area 43. If a signal having a large difference from the signal held in the D-FF 21 is output from the image sensor 1, it is considered that smear has occurred. Only in that case, in the next field period, a set signal is input to the D-FF 27 via the AND gate 25 and the OR gate 26, and the Q output becomes H level. Therefore, the changeover switch 2
8 is switched to the solid line side.

By subtracting the output of the solid-state imaging device 1 by the output of the line memory 3 in the same manner as in the first embodiment, the pixel signal from which the smear component has been removed from the next field is output. Output from On the other hand, if no smear occurs, the output of the subtractor 22 remains at a low level. Therefore, the output of the comparator 23 becomes L level, and the D-FF 27
B remains reset. Therefore, the switch 28 is held on the dotted line side, and the pixel signal held in the line memory 3 is not output. Therefore, the subtractor 5 calculates A /
The pixel signal output from the D converter 2 is output as it is. By doing so, it is possible to output a pixel signal having no side effect when no smear occurs.
Therefore, a solid-state imaging device that solves the first problem can be realized.

(Embodiment 3) Next, a solid-state imaging device according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 6 is a block diagram illustrating a configuration of the solid-state imaging device according to the present embodiment. This solid-state imaging device includes:
As in the second embodiment, A /
D converter 2, line memory 3, timing generation circuit 4
C, subtractor 5, drive circuit 7, subtractor 22, comparator 23,
Constant generator 24, AND gate 25, OR gate 26,
A D flip-flop 27 and a changeover switch 28 are provided. The difference from the second embodiment is that the subtractor 22 subtracts the current signal from the signal held in the line memory 3, and the absolute value circuit 29 is provided after the subtractor 22. Further, an inverting circuit 30 is provided at the Q output terminal of the D-FF 27 in order to reverse the switching control of the switch 28 in the second embodiment. The blocks with the same reference numerals as those in FIG.
Since the configuration and the function are the same, the description is omitted.

Here, the constant generator 24, the absolute value circuit 2
9, comparator 23, AND gate 25, OR gate 26,
The D flip-flop 27 detects the presence or absence of the movement of the subject based on the difference value between the dummy signal of the specific field held in the line memory 3 and the output signal of the solid-state imaging device 1 in the field following the specific field. It has the function of detecting means.

The operation of the solid-state imaging device having such a configuration will be described with reference to FIG. At the timing when the solid-state imaging device 1 outputs the dummy line, the timing generation circuit 4C
7 outputs a reset signal R as shown in FIG. This reset signal resets the D-FF 27,
The Q output becomes L level. In this state, the changeover switch 28 is in a state shown by a solid line. As shown in FIG. 7D, the signal WE of the timing generation circuit 4C is at the H level during the period in which the dummy area 43 of each field is scanned.
The signal read from the solid-state imaging device 1 during this period is recorded in the line memory 3 and held for one field.

When the scanning of the dummy area 43 is completed and the scanning of the imaging section 41 is started, the subtracter 22 subtracts the pixel signal currently being scanned from the signal held in the line memory 3. This subtraction value is given to the absolute value circuit 29 and is converted into a difference value. As shown by the spike pulse in FIG. 7C, if the smear occurrence position of each horizontal scanning line does not change, the difference value becomes small and becomes equal to or less than the constant A. In this case, the output of the comparator 23 becomes L level. However, the signal WE is not output until the next field period.

When a high-luminance subject is stationary, the position where the smear occurs does not change between fields. Therefore, in the next field period, a new signal WE is output from the timing generation circuit 4C. At this timing, a signal in the dummy area 43 of the new field is input to the line memory 3. Then, the signal taken in the previous field at the same time as the input is read out from the line memory 3,
It is output to the subtractor 22. Also in this case, the difference value output from the absolute value circuit 29 becomes small, and becomes smaller than the constant A. Also in this case, the output of the comparator 23 is at the L level. Now, since the signal WE is at the H level, the output of the comparator 23 is AND
The signal is output to the D-FF 27 via the gate 25 and the OR gate 26. Also in this case, since the output of the comparator 23 is at the L level, the D-FF 27 is not set. In this case, the changeover switch 28 selects the pixel signal held in the line memory 3 and outputs it to the subtracter 5. The subtractor 5 subtracts the pixel signal of the line memory 3 from the pixel signal output from the A / D converter 2 and outputs the result. As described above, when the smear occurrence position does not change, a pixel signal from which smear has been removed is output from the output terminal 6. When the high-luminance subject is stationary as described above, it is possible to output a pixel signal from which smear has been removed by utilizing the fact that the smear occurrence position does not change between fields.

Next, consider the case where a high-luminance subject is moving. In this case, the smear occurrence position changes between horizontal scanning lines or fields. Therefore, the signal held in the line memory 3 changes between fields.
The output level of the absolute value circuit 29 increases during any of the horizontal scanning lines, and when this level exceeds a constant A,
Comparator 23 outputs an H level signal. When the signal WE becomes H level in the next field, the H output of the comparator 23 is supplied to the D-FF via the AND gate 25 and the OR gate 26.
27. In this case, the D-FF 27 is set, and the Q output becomes H level. At this time, the changeover switch 28 enters the connection state shown by the broken line, and the subtractor 5
The pixel signal of the converter 2 is output without being subjected to signal processing.
As described above, when the subject moves, the occurrence of side effects due to smear correction is suppressed. Thus, a pixel signal without side effects can be output.

As described above, the motion of the subject is detected by comparing the dummy signals in different fields, and if the motion is detected, the output of the line memory 3 is not subtracted from the output of the solid-state imaging device 1. By doing so, the second problem can be solved.

(Embodiment 4) Next, a solid-state imaging device according to Embodiment 4 of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram illustrating a configuration of the solid-state imaging device according to the present embodiment. This solid-state imaging device includes:
As in the second embodiment, A /
D converter 2, line memory 3, timing generation circuit 4
D, a subtractor 5, and a drive circuit 7. Embodiment 2
The difference is that a coefficient generator 31 is provided as a coefficient generating means, and a multiplier 32 multiplies the signal held in the line memory 3 by a coefficient output from the coefficient generator 31, and outputs the multiplication result to the subtractor 5. It is to give. Note that blocks having the same reference numerals as those in the above-described embodiments have the same configuration and function, and thus description thereof will be omitted. Coefficient generator 31
FIG. 9 shows the relationship between the input and output signals. When the output level of the solid-state imaging device 1 is less than a, a coefficient 1 is output. When the output level is more than a, a coefficient that decreases from 1 to 0 in proportion to the excess amount is output, and when b exceeds b. A coefficient 0 is output.

The operation of the solid-state imaging device having such a configuration will be described. When the output level of the image sensor 1 is less than a, it is determined that the level of the pixel signal is not in a saturated state, and the coefficient generator 31 outputs the coefficient 1. On the other hand, the line memory 3
Is a signal W from the timing generation circuit 4D as in FIG.
Each time E is output, a pixel signal output from the solid-state imaging device 1 via the A / D converter 2 is recorded for each line,
At the same time as this recording, a pixel signal recorded in the previous field is output. Therefore, when the level of the pixel signal in the line currently being scanned is not saturated, the pixel signal of the specific line held in the line memory 3 via the multiplier 32 is given to the subtractor 5. The subtracter 5 subtracts the output signal of the multiplier 32 from the pixel signal currently output from the A / D converter 2. Therefore, when the smear component is generated at the fixed position, the pixel signal from which the smear has been removed is output from the output terminal 6.

The subject or the entire screen is bright, and the image sensor 1
The coefficient generator 31 outputs a coefficient 0 when the level of the pixel signal outputted from the coefficient generator 31 is saturated and exceeds at least the level of a in FIG. Then, the multiplier 32 multiplies the output of the line memory 3 by 0. In this case, the output of the solid-state imaging device 1 is directly output from the output terminal 6, and a pixel signal without smear correction is generated. That is, since the output luminance is saturated, substantially no smear is observed.

By multiplying the output of the line memory 3 by a coefficient corresponding to the output level of the solid-state imaging device 1, it is possible to prevent a smear component from being subtracted from a portion where the output of the solid-state imaging device 1 is saturated. Can be. For this reason, a pixel signal free from side effects due to smear correction can be obtained.
The third problem can be solved.

[0043]

According to the first to fourth aspects of the present invention, when a smear occurs in the solid-state imaging device 1, vertical streak-like noise can be removed.

According to the fifth and sixth aspects of the present invention,
If the subject is moving, the smear may not be perfectly vertical. In such a case, the operation can be performed so as not to perform the improper correction.

According to the seventh and eighth aspects of the present invention,
When the output level of the pixel signal of the solid-state imaging device 1 is already saturated, the problem that a bright portion that should be saturated appears dark due to smear correction is solved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a solid-state imaging device used in each embodiment.

FIG. 3 is a timing chart illustrating an operation of the solid-state imaging device according to the first embodiment;

FIG. 4 is a configuration diagram of a solid-state imaging device according to a second embodiment of the present invention.

FIG. 5 is a timing chart illustrating an operation of the solid-state imaging device according to the second embodiment;

FIG. 6 is a configuration diagram of a solid-state imaging device according to a third embodiment of the present invention.

FIG. 7 is a timing chart showing an operation of the solid-state imaging device according to the third embodiment;

FIG. 8 is a configuration diagram of a solid-state imaging device according to a fourth embodiment of the present invention.

FIG. 9 is a characteristic diagram of a coefficient generator used in the solid-state imaging device according to the fourth embodiment;

FIG. 10 is a configuration diagram of a solid-state imaging device in a conventional example.

FIG. 11 is a timing chart showing an operation of a conventional solid-state imaging device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid-state image sensor 2 A / D converter 3 Line memory 4A, 4B, 4C, 4D Timing generation circuit 5, 22 Subtractor 6 Output terminal 7 Drive circuit 8 Adder 9 Divider 10 Switch 21, 27 D-FF 23 Comparison Device 24 constant generator 25 AND gate 26 OR gate 28 selector switch 29 absolute value circuit 30 inverting circuit 31 coefficient generator 32 multiplier 40 photoelectric conversion element 41 imaging unit 42 OB area 43 dummy area 44 horizontal transfer CCD 45 photoelectric conversion element array 46 Vertical transfer CCD

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuzo Magami 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.F-term (reference) 5C021 PA52 PA58 PA66 PA67 PA78 PA85 PA92 RA01 YA09 5C024 AA01 CA04 FA01 FA11 GA52 HA02 HA03 HA12 HA14 HA17 HA18 HA20 HA23

Claims (8)

[Claims] 1. A photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix and photoelectrically converts imaging light of a subject, a light-shielding photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded, the photoelectric conversion unit, and the light shielding A solid-state imaging device having a vertical transfer register unit for vertically transferring imaging charges from the photoelectric conversion unit and a horizontal transfer register unit for horizontally transferring the imaging charges vertically transferred from the vertical transfer register units in a line-sequential manner is used. A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, wherein the output signal of the solid-state image sensor is A line memory that stores a dummy signal generated from a plurality of lines located in the light-shielded photoelectric conversion unit, and a signal held in the line memory. An averaging unit for averaging a plurality of lines of dummy signals located in the photoelectric conversion unit, and a subtraction unit for subtracting an output signal of the averaging unit from an output signal of the solid-state imaging device. Solid-state imaging device. 2. The system according to claim 1, wherein the line memory accumulates and stores, for each line, a dummy signal of the same field generated by the light-shielded photoelectric conversion unit, and outputs a cumulative addition value of the dummy signal. Item 2. The solid-state imaging device according to Item 1. 3. A photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix to photoelectrically convert image pickup light of a subject, a light-shielding photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded, the photoelectric conversion unit, and the light shielding. A solid-state imaging device having a vertical transfer register unit for vertically transferring imaging charges from the photoelectric conversion unit and a horizontal transfer register unit for horizontally transferring the imaging charges vertically transferred from the vertical transfer register units in a line-sequential manner is used. A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, wherein the output signal of the solid-state image sensor is Among them, a line memory for storing a dummy signal generated from a line located in the light-shielding photoelectric conversion unit, and a left end or a right end of a line located in the light-shielding photoelectric conversion unit. OB area storage means for storing a mee signal, first subtraction means for subtracting the output signal of the OB area storage means from the output signal of the solid-state imaging device, and the level of the output signal of the first subtraction means A level monitoring unit that monitors whether it is less than or greater than a threshold, and, in a monitoring result of the level monitoring unit, when the signal level is greater than or equal to the threshold, outputs a signal from the line memory
When the monitoring result is less than the threshold, the switching unit outputs a 0 signal, and the second subtraction unit subtracts the output signal of the switching unit from the output signal of the solid-state imaging device. Solid-state imaging device. 4. The level monitoring means outputs a monitoring result by comparing a level of a dummy signal at a left end or a right end of a line located in the light-shielded photoelectric conversion unit with a level of a dummy signal other than the left or right end of the line. 4. The solid-state imaging device according to claim 3, wherein: 5. A photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix and photoelectrically converts imaging light of a subject, a light-shielded photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded, the photoelectric conversion unit, and the light-shielding A solid-state imaging device having a vertical transfer register unit for vertically transferring imaging charges from the photoelectric conversion unit and a horizontal transfer register unit for horizontally transferring the imaging charges vertically transferred from the vertical transfer register units in a line-sequential manner is used. A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, wherein the output signal of the solid-state image sensor is A line memory for storing a dummy signal generated from a line located in the light-shielded photoelectric conversion unit, and a dummy for a specific field held in the line memory. Motion detection means for detecting the presence or absence of motion of the subject based on a difference value between the signal and an output signal of the solid-state imaging device in a field following the specific field; and 0 signal when the motion detection means detects that there is motion. And a switching unit that outputs a signal of the line memory when detecting that there is no motion, and a subtraction unit that subtracts an output signal of the switching unit from an output signal of the solid-state imaging device. Characteristic solid-state imaging device. 6. The motion detecting means compares a dummy signal of the same light-shielding line between different feeds, and if a difference value between fields is equal to or more than a predetermined value,
6. The apparatus according to claim 5, wherein it is determined that the subject has movement.
The solid-state imaging device according to claim 1. 7. A photoelectric conversion unit in which photoelectric conversion elements are arranged in a matrix and photoelectrically converts imaging light of a subject, a light-shielding photoelectric conversion unit in which a plurality of lines of photoelectric conversion elements are shielded, the photoelectric conversion unit, and the light-shielding. A solid-state imaging device having a vertical transfer register unit for vertically transferring imaging charges from the photoelectric conversion unit and a horizontal transfer register unit for horizontally transferring the imaging charges vertically transferred from the vertical transfer register units in a line-sequential manner is used. A solid-state imaging device that removes a signal component other than pixel light of a subject among pixel signals output through the vertical transfer register unit and the horizontal transfer register unit, wherein the output signal of the solid-state image sensor is A line memory for storing a dummy signal generated from a line located in the light-shielded photoelectric conversion unit, and a predetermined value when an output level of the solid-state imaging device increases. Coefficient generating means for generating a coefficient to be reduced; a multiplier for multiplying an output of the coefficient generating means by an output of the line memory; and a subtracting means for subtracting an output of the multiplier from an output signal of the solid-state imaging device. , A solid-state imaging device. 8. The coefficient generating means outputs a coefficient 1 when a and b are constants satisfying a <b, and a pixel value x output from the line memory is 0 ≦ x <a. When x is a <x ≦ b, the coefficient (x−b) /
8. The solid-state imaging device according to claim 7, wherein (ab) is output, and a coefficient 0 is output when b <x.