JP2708822B2 - Imaging device - Google Patents

Description

The present invention relates to an imaging device such as a television camera provided with a CCD solid-state imaging device.

(B) Conventional technology In the case of the NTSC system, the playback screen of a general television is composed of 240 pixels vertically and 324 pixels horizontally, and an image sensor corresponding to at least the number of pixels is required to obtain this screen. Become. However, since a solid-state imaging device having a large number of pixels requires high integration, the manufacturing yield cannot be improved and the cost increases, resulting in a problem that the price of the television camera is increased.

Accordingly, the applicant of the present application has proposed an imaging apparatus for enabling the use of a low-resolution solid-state imaging device having a small number of pixels.
-20458. FIG. 6 is a block diagram showing the configuration of the imaging apparatus, and FIG. 7 is a timing chart showing the operation.

Frame transfer type CCD solid-state image sensor (1)
Is composed of an imaging unit (I), a storage unit (S), and a horizontal register (H). The number of pixels in the vertical direction and the horizontal direction of the imaging unit (I) is omitted to half of that of a normal element, respectively. I have. For example, in the case of NTSC system, vertical
It is formed of 120 pixels and 162 pixels horizontally. This CCD (1)
Are pulse-driven by the drive pulse generation circuit (2), and the readout transfer pulse φ _F and the storage transfer pulse φ are respectively supplied to the imaging unit (I), the storage unit (S), and the horizontal register (H).
_S and horizontal transfer pulse phi _H is supplied. The drive pulse generation circuit (2) performs the CCD (1) according to the timing pulse generated by the timing control circuit (3) based on the vertical blanking pulse VD and the horizontal blanking pulse HD.
Are supplied with transfer pulses φ _F , φ _S and φ _H.

In the above-described CCD (1), since the number of pixels in the vertical direction and the horizontal direction is 1/2 of the normal number, when the image charge is read out from the storage unit (S) by the transfer pulse having the same cycle as the horizontal blanking pulse, the driving is performed. , The number of horizontal scanning lines can be reduced to only 1/2, and a television screen cannot be constructed. Therefore, the accumulation transfer pulse φ _S
The period between the horizontal transfer pulse phi _H is twice the period of the horizontal blanking pulse HD. That is, the transfer of the image charge from the storage section (S) to the horizontal register (H) is performed every 2H cycle. Therefore, in the image signal X (t) obtained from the CCD (1), a signal exists for 1H time every 2H period.

Such an image signal X (t) is output to a signal processing circuit (4).
Then, processing such as sample hold and amplification is performed to obtain an image signal Y ₀ (t) shown in FIG. This image signal Y ₀ (t)
Is an intermittent signal in which a signal exists for only 1H period every 2H period, and is input to the interpolation circuit (5) in order to make it a continuous signal. The interpolation circuit (5) calculates the image signal Y
₀ (t) is delayed (51) by 1H period, and the image signal Y ₀ ′
(T), the image signal Y ₀ ′ (t) and the image signal Y
By adding (52) to ₀ (t), a continuous image signal Y ₁ (t) is output every 1H period.

According to the above configuration, a horizontal scanning line of a reproduction screen can be obtained by the same signal for every two lines, and a CCD having a small number of pixels can be used in a television camera.

(C) Problems to be Solved by the Invention Even in the above-described imaging apparatus, it is possible to improve the horizontal resolution by interlacing the CCD (1), but the interpolation circuit ( The imaging device provided with 5) has the following disadvantages.

That is, when an image of a subject as shown in FIG.
First, in the odd field ODD, the areas O1 to O3 are imaged, and O1, O1 to O3, O3 (solid lines) shown in FIG. 4B are drawn, and the next even field EVEN shown in FIG. The area E3 is imaged, and E1, E1 to E3, and E3 shown in FIG. Therefore, as is apparent from the figure, the position of each area may be reversed between the subject and the reproduction screen. For example, in the subject
O2 is located above E2, whereas O2 is
Is generated below E2. Therefore, although the CCD (1) is interlaced, it is not possible to improve the image quality of the reproduction screen.

Therefore, an object of the present invention is to solve the inconvenience of interlaced driving of a CCD in an imaging device using a CCD solid-state imaging device having a small number of pixels.

(D) Means for Solving the Problems The present invention has been made to solve the above problems, and the first means is characterized in that a plurality of light receiving pixels are arranged in rows and columns and a vertical direction. The number of pixels of the array is set to に 対 し て of the number of horizontal scanning lines of the reproduction screen, and a solid-state imaging device that accumulates information charges corresponding to an image pattern in each light receiving pixel by photoelectrically converting a received image. A driving circuit that reads out and drives information charges accumulated in each light receiving pixel of the solid-state imaging device every other horizontal scanning period to obtain an intermittent image signal, and stores an image signal obtained from the solid-state imaging device for each even field. A first memory circuit, a second memory circuit for storing an image signal obtained from the solid-state imaging device for each odd field, a read drive timing of the drive circuit, and writing of the first and second memory circuits. In,
A timing control circuit for controlling read and read operations; and an adder circuit for adding signals read from the first and second memory circuits. The image signal is alternately stored in the first and second memory circuits for each field. And an image signal is alternately read from the first and second memory circuits in each horizontal scanning period.

The second means is characterized in that a plurality of light receiving pixels are arranged in a matrix, and the number of pixels arranged in the vertical direction is set to 1/2 of the number of horizontal scanning lines on the reproduction screen, and light is received. A solid-state imaging device that stores information charges corresponding to an image pattern in each light-receiving pixel by photoelectrically converting an image, and reads and drives the information charges stored in each light-receiving pixel of the solid-state imaging device every other horizontal scanning period. A drive circuit for obtaining an intermittent image signal, a memory circuit for storing an image signal obtained from the solid-state imaging device, a timing control circuit for controlling read drive timing of the drive circuit and writing and reading of the memory circuit, An addition circuit for adding an image signal obtained from an image sensor and a signal read from the memory circuit, wherein the image signal is stored in the memory for each field. Together are stored in the road, the image signal of the next field is to be interpolated in the horizontal scanning period unit depending on the image signal read from said memory circuit.

(E) Function According to the present invention, when a solid-state imaging device having a vertical pixel number of 1 / n of the number of horizontal scanning lines of a playback screen is interlaced, an image of an even field and an odd field constituting one frame is formed. By storing a signal in a memory circuit and reading and driving the signal every horizontal scanning period to form a reproduced screen,
The arrangement of the horizontal scanning lines on the reproduction screen can be changed so as to follow the image received by the solid-state imaging device, and the inversion of the arrangement order of the horizontal scanning lines on the reproduction screen does not occur when interlaced driving is performed.

(F) Embodiment One embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the imaging apparatus of the present invention. In this figure, the CCD (1) has the number of pixels in the vertical direction and the horizontal direction of the imaging unit (I) omitted to half of that of a normal element, and this CCD (1) is a driving pulse generating circuit (2). ), The pulse is driven at the timing shown in FIG. CCD
The image signal X (t) obtained from (1) is subjected to processing such as sample hold and amplification in the signal processing circuit (4), and is output as an image signal Y ₀ (t). The configuration up to the signal processing circuit (4) is the same as in FIG. 6, and therefore, the image signal Y ₀ (t) is the same as in FIG.

The image signal Y ₀ (t) is supplied to the ODD via the A / D conversion circuit (10).
Input to the memory (11) and the EVEN memory (12). ODD
Memory (11), the image signal Y ₀ of the odd field only (t) stored in each field, EVEN memory (12) stores the image signal Y ₀ alone (t) for each one field of an even field. Writing of signals to the memories (11) (12), the write control signal WE _O supplied from the timing control circuit (3 '), intended to be controlled by the WE _E, in synchronization with a vertical blanking pulse VD It is done. Then, the image signals read from both memories (11) and (12) are added by an addition circuit (13), and an image signal Y ₁ (t) is obtained via a D / A conversion circuit (14). Reading of signals from both memories (11) and (12) is controlled by read control signals RE _O and RE _E supplied from a timing control circuit (3 ′).
It is performed alternately every horizontal scanning period.

That is, as shown in FIG. 2, the read control signals RE _O and RE _E are set so that the signal is read only during the 1H period every 2H period, and the read timing is set to 1H between each other.
It is set out of time. Therefore, when the blanking period of the vertical blanking pulse VD ends, the ODD memory (1
1) The signal is read alternately with the EVEN memory (12) every 1H period. Therefore, the image signals stored in the ODD memory (11) are defined as O1, O2, O3,... In units of horizontal scanning lines, and the image signals stored in the EVEN memory (12) are defined in units of horizontal scanning lines.
Assuming that E1, E2, E3,..., The image signal Y ₁ (t) obtained by adding in the adder circuit is O1, E1, O2, E2,
Are output in the order of ... This order is determined by the read control signal
It is determined by RE _O and RE _E , and is always kept constant.

Therefore, when an image of the subject shown in FIG.
The playback screen is O in an odd field as shown in FIG.
Horizontal scanning lines are drawn in the order of 1, E1, O2, E2, O3, E3 (solid line), and horizontal scanning lines are drawn in the order of O1, E1, O2, E2, O3, E3 (dashed line) in even fields. In other words, a reproduction screen faithful to the subject is formed.

FIG. 4 is a block diagram showing the configuration of another embodiment of the present invention. In this configuration, one field memory (15) is used instead of the ODD memory (11) and the EVEN memory (12), and a signal read from the field memory (15) and a signal obtained from the signal processing circuit (4) are obtained. Image signal Y
_The image signal Y ₁ (t) is obtained by adding ₀ (t) to the addition circuit (13). That is, the image signal Y ₀ (t) obtained from the signal processing circuit (4) is stored in the field memory (1).
5) is stored for each field and the addition circuit (1
The image signal Y ₀ (t) one field before, which is input to 3) and stored in the field memory (15), is added by the adding circuit (13). The writing and reading of the signal of the field memory (13) are controlled by a write control signal WE and a read control signal RE supplied from the timing control circuit (3 ″), and the vertical blanking pulse VD and the horizontal blanking pulse HD are controlled. The write control signal WE and the read control signal RE are synchronized as shown in FIG.
It is set so that writing and reading are performed in 1H period every 2H period. Therefore, in the even field EVEN, the field memory (15) stores the odd field one field before.
ODD image signal Y ₀ (t) (O1, O2, O3,.
) Is stored, and this is O1, O2, O every 2H period.
3,... Are sequentially read. And a signal processing circuit (4)
Image signal Y ₀ (t) (E1, E2, E3,
.. Are added to form an image signal Y ₁ (t) that is continuous with O1, E1, O2, E2,. Here, after O1, O2, O3, ... are read out to the field memory (15), E1, E
2, E3, ... are stored.

On the other hand, in the odd field ODD, the field memory (1
5) Signals E1 and E of even field EVEN one field before
... are stored, and are sequentially read out as E1, E2, E3, ... every 2H period, and the signals O1, O2, O from the signal processing circuit (4) are stored.
Are added to obtain an image signal Y ₁ (t) continuous with O1, E1, O2, E2,. This odd field OD
In the case of D, similarly to the even field EVEN, after E1, E2, E3,... Are read out to the field memory (15), O1, O2, O3,
... is stored. However, in the odd field ODD, the read timing of the read control signal RE is set to be delayed by 2H period compared to the even field EVEN in order to output O1 before E1.

According to the above configuration, the horizontal scanning lines are arranged in a fixed order regardless of the even-numbered field EVEN and the odd-numbered field ODD. Is not reversed.

(G) Effects of the Invention According to the present invention, when a solid-state imaging device whose number of vertical pixels is 1 / n of the number of horizontal scanning lines of the reproduction screen is interlaced, the arrangement order of the horizontal scanning lines on the reproduction screen is Since the reversal does not occur, the interlaced drive can be fully utilized, and the resolution can be improved and the image quality of the reproduced screen can be improved.

[Brief description of the drawings]

1 to 5 relate to the present invention, FIG. 1 is a block diagram showing the configuration of one embodiment, FIG. 2 is a timing chart showing the operation of FIG. 1, and FIG. FIG. 4 is a block diagram showing a configuration of another embodiment,
FIG. 5 is a timing chart showing the operation of FIG. Sixth
FIG. 7 is a block diagram showing the configuration of a conventional image pickup apparatus, FIG. 7 is a timing chart showing the operation of FIG. 6, and FIG. 8 is a schematic diagram showing the relationship between a subject and a playback screen. (1) CCD solid-state imaging device, (2) drive pulse generation circuit, (3) (3 ′) (3 ″) timing control circuit, (4) signal processing circuit, (11) … ODD memory,
(12) EVEN memory (13) Adder circuit (15)
... field memory.

Claims (2)

(57) [Claims] A plurality of light receiving pixels are arranged in a matrix.
The number of pixels arranged in the vertical direction is set to half the number of horizontal scanning lines on the playback screen, and a solid-state image sensor that stores information charges corresponding to the image pattern in each light receiving pixel by photoelectrically converting the received image A drive circuit for reading out information charges accumulated in each light receiving pixel of the solid-state imaging device every other horizontal scanning period to obtain an intermittent image signal, and for outputting an image signal obtained from the solid-state imaging device for each even field. A first memory circuit for storing, a second memory circuit for storing an image signal obtained from the solid-state imaging device for each odd field, a read drive timing of the drive circuit and a write of the first and second memory circuits, A timing control circuit for controlling read and read operations; and an adder circuit for adding signals read from the first and second memory circuits. An image pickup apparatus, wherein the image signal is alternately written to the re-circuit for each field, and the image signal is alternately read from the first and second memory circuits for each horizontal scanning period. 2. A plurality of light receiving pixels are arranged in a matrix.
The number of pixels arranged in the vertical direction is set to half the number of horizontal scanning lines on the playback screen, and a solid-state image sensor that stores information charges corresponding to the image pattern in each light receiving pixel by photoelectrically converting the received image A drive circuit for reading out information charges accumulated in each light receiving pixel of the solid-state imaging element every other horizontal scanning period to obtain an intermittent image signal, and a memory circuit for storing an image signal obtained from the solid-state imaging element A timing control circuit that controls the read drive timing of the drive circuit and the writing and reading of the memory circuit, an addition circuit that adds an image signal obtained from the solid-state imaging device and a signal read from the memory circuit, The image signal is stored in the memory circuit for each field, and the image signal of the next field is read from the memory circuit. An image pickup apparatus wherein interpolation is performed in units of a horizontal scanning period according to an image signal.