JPH06334926A - Image pickup device - Google Patents

Abstract

(57) [Abstract] [Purpose] An image pickup device conforming to the NTSC system is used so that the image pickup device can be used as a video input device such as a computer system or a videophone device. [Structure] The frequency of the horizontal scanning pulse is set to f ₀ (9.6 MHz).
The solid-state image sensor 2 based on the NTSC system, which is referred to as z), has a frequency of 4 f _sc (approximately 1) from the timing pulse generation circuit 6.
Imaging is performed using a horizontal scanning pulse of 4.3 MHz). The output signal of the solid-state imaging device 2 is converted into a digital signal by the A / D converter 3, and the video signal is generated by the video signal generation circuit 4. This video signal has a screen whose horizontal direction is f ₀ /
Since it has been reduced by 4f _sc times, the electronic zoom signal processing circuit 5 performs electronic zoom processing on this video signal so that the horizontal direction of the screen is enlarged by 4 f _sc / f ₀ times.
From these, a digital video signal having an aspect ratio equal to that of the NTSC system and a sampling frequency of 4 f _sc , which can be applied to a computer system, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device for generating a digital video signal, and more particularly to an image pickup device suitable for use in a computer system, a videophone device or the like.

[0002]

2. Description of the Related Art Image pickup devices such as video cameras have various functions developed with the spread of digital signal processing, while they can output digital video signals. It is gaining attention as a video input means such as.

However, at present, in computer systems, the sampling frequency of digital video signals is NTS.
Color subcarrier frequency f _sc (= 3.58 MHz) in C method
4 f _sc (about 14.3 MHz) and scanning pulse (9.6 MHz) in the solid-state image sensor in the television system.
Since it is different from the frequency of, the special image input means such as a line scanner is used only. In addition, in the videophone device, the "Journal of the Television Society of Japan" Vo
l. 46, No. 4, 1992 pp. 117-12
As described in No. 0, the signal standard CIF, which is different from the conventional video signal standard such as the NTSC system, is the standard. However, the solid-state image sensor and the image pickup device that meet the CIF standard have not been commercialized. However, the analog video signal obtained from an image pickup device such as a general video camera is A / D converted into a digital video signal, and the sampling frequency thereof is converted to obtain a sampling frequency that meets the CIF standard. I am trying to get the video signal of.

[0004]

As described above, a solid-state image pickup device or image pickup device suitable for each of image input means of a computer system, a videophone device, or the like is newly developed, or a general image pickup device is used. A large-scale conversion circuit for converting a typical analog video signal into a digital video signal having a sampling frequency and a scanning line number suitable for each is required.

The present invention has been made in view of the above points, and it is an object of the present invention to avoid an increase in circuit scale by using a general solid-state image pickup device of NTSC system,
An object of the present invention is to provide an image pickup device suitable as a video input device such as a computer system or a videophone device.

[0006]

In order to achieve the above object, the present invention provides an image pickup apparatus comprising a solid-state image pickup device having a horizontal scanning pulse frequency of f _{0 according} to the NTSC standard. The frequency of the horizontal scanning pulse of the device is 4f _sc
(> F ₀ ), an A / D converter that converts the output signal of the solid-state imaging device into a digital signal, and a video signal generation circuit that generates a digital video signal from the digital signal,
An electronic zoom signal processing circuit for performing a zoom process on the digital video signal is provided so that the image is enlarged in the horizontal direction.

Further, the present invention is an image pickup apparatus equipped with an NTSC standard solid-state image pickup device having a horizontal scan pulse frequency of f ₀ , wherein the horizontal scan pulse frequency of the solid-state image pickup device is 4f _sc. Is divided into n by a horizontal synchronizing pulse, and this horizontal synchronizing pulse is divided by m to be a vertical synchronizing pulse, and an A / D converter for converting an output signal of the solid-state image pickup device into a digital signal, and the digital signal A video signal generation circuit for generating a digital video signal from the digital video signal and an electronic zoom signal processing circuit for performing a zoom process on the digital video signal so that the image is expanded in the horizontal and vertical directions are provided.

[0008]

[Operation] NTSC as a horizontal scanning pulse for a solid-state image sensor
By using a pulse having a frequency of 4f _sc , which is four times the color subcarrier frequency f _sc of the method, it is possible to obtain a video signal whose sampling frequency is standardized to 4 fsc. Here, in this solid-state imaging device, the frequency f ₀ of the normal horizontal scanning pulse in the NTSC system is 4f _sc ≧ f ₀ , but when 4f _sc > f ₀ , the screen by the output signal of the solid-state imaging device is The image is reduced in the horizontal direction, and as it is, a screen with a normal aspect ratio cannot be obtained. Therefore, the electronic zoom signal processing causes the screen to move horizontally by 4 f.
Enlarge to _sc / f ₀ times to obtain a normal aspect ratio.

Further, a horizontal synchronizing pulse is generated at a frequency of 4f _sc.
The horizontal synchronizing pulse is divided by n to generate a horizontal synchronizing pulse, and the horizontal synchronizing pulse is divided by m to obtain the vertical synchronizing pulse. Therefore, by appropriately setting n and m, It is possible to obtain a video signal with a sampling frequency standardized to 4f _sc in any format.

Here, the number of horizontal effective pixels of the solid-state image pickup device of the NTSC system is N ₀ (for example, 510 pixels), and the number of pixels N (n ≧ N) of the signal required on the input side is twice as large as that of the CIF standard ( In the case of N> N ₀ such as (N = 720), a signal in which the screen is horizontally reduced is output from the solid-state image pickup device, and thus the electronic zoom signal processing causes N / N ₀ times in the horizontal direction. Expand to. Similarly, the number of lines per field in an NTSC video signal is M ₀ (242 lines), and the number of signal lines required on the input side is M (m ≧
M> M such as CIF standard (M = 288)
_{When the value} is ₀ , a signal in which the screen is reduced in the vertical direction is output from the solid-state image pickup element, and thus the image is enlarged in the vertical direction by M / M ₀ times by the electronic zoom signal processing. As a result, a video signal of an arbitrary format without a screen drop can be obtained.

[0011]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
1 is a block diagram showing an embodiment of an image pickup apparatus according to the present invention, in which 1 is a lens, 2 is a solid-state image sensor, and 3 is an A / D.
(Analog / digital) converter, 4 is a video signal generation circuit, 5 is an electronic zoom signal processing circuit, 6 is a timing pulse generation circuit, 7 is a crystal oscillator, and 8 and 9 are output terminals.

In FIG. 1, a lens 1 forms an optical image of a subject on an image pickup surface of a solid-state image pickup device 2. The solid-state image pickup device 2 scans this optical image by the scanning pulse from the timing pulse generating circuit 6 and outputs an electric signal representing this optical image. The timing pulse generation circuit 6 generates this scanning pulse from the clock φ output from the crystal oscillator 7. The output signal of the solid-state image sensor 2 is converted into a digital video signal by the A / D converter 3 based on the clock from the timing pulse generation circuit 6, and is supplied to the video signal generation circuit 4 to be processed such as γ correction. Further, the digital luminance signal Y and the digital color signal C are generated.

Here, the solid-state image pickup device 2 is a normal solid-state image pickup device used in a standard type (here, NTSC type) image pickup device, but as will be described later, it is a standard type from the timing pulse generation circuit 6. With a horizontal scanning pulse higher than the horizontal scanning pulse of, the video signal of the image whose aspect ratio is compressed in the horizontal direction is output.

Therefore, the digital luminance signal Y and the digital color signal C output from the video signal generating circuit 4 are supplied to the electronic zoom signal processing circuit 5 and are horizontally supplied by the timing pulse supplied from the timing pulse generator 6. A digital luminance signal Y and a digital color signal C having a standard aspect ratio are obtained by zooming in the direction. The digital luminance signal Y and the digital color signal C are output from the output terminals 8 and 9, respectively.

FIG. 2 is a diagram showing an image pickup portion of a concrete example of the solid-state image pickup element 2 in FIG. 1, in which 2a is a photodiode, 2b is a vertical CCD (charge coupled device), and 2c is a horizontal C.
It's a CD.

A predetermined number of photodiodes 2a are arranged in a matrix on the image pickup surface of the solid-state image pickup device 2, and a vertical CCD is provided for each column of the photodiodes 2a in the vertical direction.
2b is provided. Each vertical CCD 2b is connected to the horizontal CCD 2c. Each photodiode 2
Reference numeral a is an effective pixel, which generates and accumulates electric charges according to the amount of light of the optical image formed on each.

In such a configuration, when the read pulse is supplied from the timing pulse generating circuit 6 (FIG. 1) within the vertical blanking period, the charges are transferred from the photodiodes 2a of each column to the vertical CCD 2b corresponding to the column all at once. To be done. As a result, in each vertical CCD 2b, the charges from the photodiodes 2a in one row are held in line in the order of arrangement of the photodiodes 2a.

Next, a vertical scanning pulse is supplied from the timing pulse generating circuit 6. When this vertical scanning pulse is supplied, the charges of the two adjacent upper and lower photodiodes 2a are mixed and transferred from the lower part of the vertical CCD 2b upward to the upper part of the vertical CCD 2b every two lines in the horizontal blanking period. The charges are simultaneously transferred to the horizontal CCD 2c.
Here, when the horizontal operation pulse is supplied to the horizontal CCD 2c, the charges are sequentially transferred and output from the left side to the right side of the horizontal CCD 2c. This operation is repeated until the charges of all the vertical CCDs 2b are output. When all the charges are output, the read pulse is supplied again and the above operation is repeated. In this case, the combination of the two photodiodes 2a in which the charges are mixed is different for each field. As a result, interlacing is performed.

Here, in a general solid-state image pickup element used in an NTSC type image pickup device, the number of effective pixels is 510 pixels in the horizontal direction and 492 pixels in the vertical direction, and the normal aspect ratio (3: 4) is The frequency of the horizontal scan pulse to be obtained is 9.6 MHz. FIG. 3A shows a video signal when the frequency of the horizontal scanning pulse is set to 9.6 MHz in this way.

In this embodiment, assuming that the color subcarrier frequency in the NTSC system is f _sc (= 3.58 MHz), the frequency of the horizontal scanning pulse is 4 times that frequency, 4 f _sc (approximately 14.
3 MHz). In FIG. 1, the crystal oscillator 7 is approximately 2
A clock φ having a frequency of 8.6 MHz is generated, and the timing pulse generation circuit 6 divides this clock φ by 2 to generate a horizontal scanning pulse of 4 f _sc (approximately 14.3 MHz).

By using the horizontal scanning pulse in the solid-state image sensor 2, the output signal of the solid-state image sensor 2 becomes
The frequency of the pixel signal is 4f _sc , and the A / D converter 3
Is digitized with a sampling pulse frequency of 4 f _sc and a quantization bit number of 8. The digital signal output from the A / D converter 3 is supplied to the video signal generation circuit 4, and the digital video signal output from the video signal generation circuit 4 is horizontally scanned by the solid-state image sensor 2 as described above. Since the pulse frequency is 4 f _sc , the image signal of the screen is horizontally reduced at a ratio of 9.6 / 14.3 compared to the aspect ratio of the NTSC system, as shown in FIG. 3 (b). As compared with the video signal of the NTSC system shown in FIG. 3A, the video signal is time-reduced for each horizontal scanning period. The electronic zoom signal processing circuit 5 temporally extends the video signal by 14.3 / 9.6 times for each horizontal scanning period by the timing pulse from the timing pulse generating circuit 6, and as a result, FIG. As shown in (c), the same aspect ratio as the video signal shown in FIG.
That is, a video signal having an aspect ratio equal to that of the NTSC system can be obtained.

An example of such an electronic zoom signal processing circuit 5 is described in Japanese Patent Laid-Open No. 4-10783. It uses a memory unit, to which the writing with the timing pulse frequency of the sample data 4f _sc frequency shown in FIG. 3 (b) to 4f of the video signal shown _sc (approximately 14.3 MHz), the timing of frequency of 4f _sc The timing of reading each sample data from the memory means is appropriately selected by a pulse to extend the time axis, and the read sample data is processed to generate interpolated sample data. This makes the sampling frequency 4
At f _sc , the video signal shown in FIG. 3C is obtained in which the time length for each horizontal scanning period is equal to the video signal shown in FIG. 3A.

In this way, the digital video signals of the digital luminance signal Y and the digital color signal C obtained at the output terminals 8 and 9 have the frame frequency and the horizontal synchronizing frequency according to the NTSC system as shown in FIG. Compliant 3
3.37 msec, 63.56 μsec, sampling period 70 nsec (sampling frequency is 4 f
_sc ≒ 14.3 MHz), comprised of a digital luminance signal Y and digital color signal C of the quantized bit count 8, further chrominance signal C is time-division two color difference signals R-Y, B-Y is at the sampling frequency 4f _sc It is multiplexed. Therefore,
The ratio of the luminance signal Y and the color difference signals RY and BY is 4: 2 :.
2, the digital video signal can be an input video signal of a computer system or the like.

As described above, in this embodiment, by using the image pickup device 2 conforming to the normally used NTSC system, it is possible to generate a digital video signal usable for a computer system or the like. Therefore, this embodiment can be used as it is as a video input means such as a computer system.

FIG. 5 is a block diagram showing another embodiment of the image pickup device according to the present invention, in which 6'is a timing pulse generating circuit and 10 and 11 are input terminals, and the parts corresponding to those in FIG. The duplicated description will be omitted with reference numerals.

In the figure, the timing pulse generating circuit 6'is similar to the timing pulse generating circuit 6 in FIG. 1 from the crystal oscillator 7 to the clock φ having a frequency of 4f _sc × k.
However, the horizontal preset value P is input from the input terminal 10.
_A vertical preset value P _v is supplied from the input terminal 11 for _h , and a scanning pulse, a synchronizing pulse, etc. of the image sensor 2 are generated from the clock φ, the horizontal preset value P _h , and the vertical preset value P _v . However, the frequency of the horizontal scanning pulse of the image sensor 2 is 4 as in the case of the image sensor 2 in FIG.
f _sc (approximately 14.3 MHz), the horizontal synchronizing pulse is obtained by dividing this horizontal scanning pulse by n using the horizontal preset value P _h (where n is a positive integer), and the vertical synchronizing pulse is It is a horizontal sync pulse divided by m (where m is a positive integer).

In this embodiment, the horizontal scanning pulse, the horizontal synchronizing pulse, the vertical synchronizing pulse and the like from the timing pulse generating circuit 6'are supplied as scanning pulses to the image pickup device 2 having the structure described with reference to FIGS. Similar to the embodiment shown in FIG. 1, the output signal of the image pickup device 2 is processed by the A / D converter 3, the video signal generating circuit 4, and the electronic zoom signal processing circuit 5, and the digital luminance signal Y is output to the output terminal 8. The digital color signal C is obtained at the output terminal 9 so that the aspect ratio of the screen is the same as that of the NTSC system.
These digital luminance signal Y and digital color signal C are C
It is adapted to the IF standard.

For this reason, the timing pulse generating circuit 6'is supplied with the horizontal preset value P _h and the vertical preset value P _v from the input terminals 10 and 11, respectively.
A specific example of the timing pulse generation circuit 6'will be described with reference to FIG. However, in the figure, 12 is a divide-by-2 circuit,
Reference numeral 13 is a horizontal counter, 14 is a vertical counter, and 15 is a pulse generation circuit. The parts corresponding to those in FIG.

Here, the solid-state image pickup device 2 has 510 effective pixels in the horizontal direction and 492 effective pixels in the vertical direction as described with reference to FIG.

In FIG. 6, a clock φ whose frequency output from the crystal oscillator 7 is 2 × 4f _sc (= approximately 28.6 MHz, where k is 2) is supplied to the timing pulse generation circuit 6 '. It is supplied and is divided by 2 by 2
The frequency division is performed to generate a horizontal scanning pulse having a frequency of 4f _sc (= approximately 14.3 MHz). This horizontal scanning pulse is supplied to the pulse generation circuit 15 and also to the horizontal counter 13. The horizontal preset value Ph from the input terminal 10 is preset in the horizontal counter 13, and the horizontal scanning pulse from the divide-by-2 circuit 12 is divided into n based on the horizontal preset value Ph to output a horizontal synchronizing pulse. The horizontal synchronizing pulse is supplied to the pulse generation circuit 15 and also to the vertical counter 14. The vertical counter 14 is preset with the vertical preset value Pv from the input terminal 11, and based on the vertical preset value Pv, divides the horizontal sync pulse from the horizontal counter 13 by m and outputs the vertical sync pulse. This vertical synchronization pulse is supplied to the pulse generation circuit 15.

The pulse generating circuit 15 uses the horizontal scanning pulse, the horizontal synchronizing pulse and the vertical synchronizing pulse to generate a frequency 4f.
horizontal scanning pulse of _sc , frequency fsc (approximately 3.58 MH
z) pulse, horizontal synchronizing pulse, field pulse, frame pulse, etc. are generated, and these are appropriately applied to the image sensor 2, the A / D converter 3, the video signal generating circuit 4, and the electronic zoom signal processing circuit 5 in FIG. Supply.

According to the CIF standard, the frame frequency is NTS.
Although it is 33.37 msec, which is equal to the C method, it is a non-interlaced method and the number of lines per frame is 288 and the number of dots per line is 360. Therefore, the number of effective pixels is 510 pixels in the horizontal direction and 4 in the vertical direction.
If the frequency of the horizontal scanning pulse is 4 f _sc using a general NTSC solid-state image sensor 2 with 92 pixels, C
In order to obtain a digital video signal of IF standard, the above-mentioned generation numbers n and m must satisfy the following conditional expressions.

M × n = 525 × 910 m ≧ (288 + 20) × 2 = 616 n ≧ 606 m: odd number n: even number where 525 is the number of lines per frame in the NTSC system and 910 is the number in the NTSC system. The number of counts when the pulse of frequency 4f _sc is counted in one horizontal scanning period (approximately 63.56 μsec), 288 and 20 are the number of lines per frame of the video signal in the CIF standard and the number of lines in the blanking period, 606. Is the number of counts when the solid-state imaging device 2 counts horizontal scanning pulses of a frequency of 9.6 MHz that can obtain a normal aspect ratio in one horizontal scanning period of the NTSC system.

To satisfy such a condition, m = 63
7, n = 750 must be present. Therefore, the horizontal preset value of the horizontal counter 13 is 750, and the vertical counter 1
The vertical preset value of 4 is 637, and the periods of the horizontal synchronizing pulse and the frame pulse are approximately 52.38 μsec,
It will be 33.37 msec.

Since the CIF standard is a non-interlaced system, the following operation is also performed in this embodiment.

That is, when non-interlacing is performed using a general NTSC type solid-state image pickup device having an effective pixel number of 510 pixels in the horizontal direction and 492 pixels in the vertical direction as the solid-state image pickup device 2, in FIG. In the field of, the vertical CCD 2 from the photodiode 2a in the 2bth row
b and the charge transferred to the second photodiode 2b + 1
The charges transferred from a to the vertical CCD 2b are
The charges are mixed in b, that is, the charges of two adjacent rows are mixed and transferred to the horizontal CCD 2c. In the next (a + 1) th field, the photodiode 2a in the 2b-1th row is
The charges transferred from the vertical CCD 2b to the vertical CCD 2b and the charges transferred from the photodiode 2a in the 2bth row to the vertical CCD 2b are mixed in the vertical CCD 2b and transferred to the horizontal CCD 2c. In other words, two adjacent to each other as in the a-th field
The charges are mixed row by row, but the adjacent two rows are different from the a-th field.

The mixing and transfer of such charges is performed by the solid-state image pickup device 2
Can be easily controlled by the scanning pulse supplied to the NTSC system, and one frame period (approximately 33.
It is possible to obtain an interlace signal of 488 lines or more in 37 msec. In this embodiment, 288 lines are approximately 33.3 with non-interlace defined by the CIF standard.
In order to obtain the frame period of 7 msec, the timing pulse generating circuit 6'supplies a scanning pulse that does not read the signal of the (a + 1) th field in the conventional interlaced operation.

Since the timing pulse generating circuit 6'performs the above control, the solid-state image pickup device 2
A signal of 288 lines / frame that meets the CIF standard is obtained. However, it is 1 for NTSC video signals.
In contrast to 510 dots per line, the CIF standard has 360 dots. In this embodiment, the output signal of the solid-state imaging device 2 is reduced in the horizontal direction as shown in FIG. Become a signal. Similarly, N
The number of effective lines per field of the TSC video signal is 242, whereas it is 288 in the CIF standard. Therefore, the output signal of the solid-state image sensor 2 is a signal that is also reduced in the vertical direction.

Therefore, in FIG. 5, the output signal of the solid-state image pickup device 2 is supplied to the A / D converter 3, is converted into a digital signal having a sampling frequency of 4 f _sc , and is supplied to the video signal generation circuit 4. In the signal generation circuit 4, the ratio is 510/720 in the horizontal direction and 2 in the vertical direction.
A digital video signal reduced at a ratio of 42/288 is generated and supplied to the electronic zoom signal processing circuit 5.
In this electronic zoom signal processing circuit 5, this digital video signal is horizontally moved at a sampling frequency of 4f _sc.
20/510 times magnification and 288/242 times magnification in the vertical direction. As a result, a digital video signal without a screen defect can be obtained.

Therefore, as shown in FIG. 7, the digital video signal obtained at the output terminals 8 and 9 in FIG. 5 is a digital video signal having a frame period of 33.37 msec, a horizontal period of 52.38 μsec and a sampling frequency of 4 f _sc. . Since the number of lines of this digital video signal is the same as that of the conventional CIF standard video signal, ie, 288, and the number of dots is 720 dots, which is doubled, a CIF standard signal can be easily generated.

[0041]

As described above, according to the present invention,
The frequency of a scanning pulse of a general NTSC type solid-state image pickup device is appropriately selected, and an output signal of the solid-state image pickup device is subjected to electronic zoom processing. It can be used as a video input means of a system such as a videophone device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image pickup apparatus according to the present invention.

FIG. 2 is a configuration diagram showing a specific example of the solid-state imaging device in FIG.

FIG. 3 is a diagram showing an operation of the electronic zoom signal processing circuit in FIG.

FIG. 4 is a diagram showing a format of a digital video signal obtained in the embodiment shown in FIG.

FIG. 5 is a block diagram showing another embodiment of the image pickup apparatus according to the present invention.

FIG. 6 is a block diagram showing a specific example of the timing pulse generation circuit in FIG.

7 is a diagram showing a CIF format of a digital video signal obtained in the embodiment shown in FIG.

[Explanation of symbols]

 2 Image sensor 3 A / D converter 4 Video signal generation circuit 5 Electronic zoom signal processing circuit 6, 6'Timing pulse generation circuit 7 Crystal oscillator 12 2 Dividing circuit 13 Horizontal counter 14 Vertical counter 15 Pulse generation circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigehisa Tabata 1410 Inada, Katsuta City, Ibaraki Prefecture Hitachi Ltd. AV Equipment Division

Claims (4)

[Claims] 1. An imaging device comprising a solid-state imaging device having a structure conforming to the NTSC system, wherein a frequency of 4f _sc × k (where f _sc is a color subcarrier frequency in the NTSC system (= 3.58 MHz), k Is a positive integer)
Clock generating means for generating a clock, a timing pulse generating circuit for dividing the clock by k, and generating a horizontal scanning pulse of the solid-state imaging device having a frequency of 4 f _sc , and a signal output from the solid-state imaging device. A / D converter for converting to a digital signal, a video signal generating circuit for processing the digital signal to generate a digital video signal, and a screen obtained by multiplying the digital video signal by 4f _sc / f ₀ (However, f ₀ is the NTSC
A digital scanning signal processing circuit for performing electronic zoom processing is provided so that the horizontal scanning pulse when generating a signal having an aspect ratio of the method) is expanded, and a digital signal having a sampling frequency of 4 f _sc is provided from the electronic zoom signal processing circuit. An image pickup apparatus characterized in that it is configured to obtain a video signal. 2. The digital video signal output from the video signal generation circuit according to claim 1, comprising a luminance signal, a first color difference signal, and a second color difference signal, the ratio of which is 4: 2: 2. An image pickup apparatus characterized by the following. 3. An image pickup apparatus comprising a solid-state image pickup device having a structure conforming to the NTSC system, wherein a frequency of 4f _sc × k (where f _sc is a color subcarrier frequency in the NTSC system (= 3.58 MHz), k Is a positive integer)
And a clock generating means for generating a clock, to generate a horizontal scanning pulse of the solid-state imaging device having a frequency of 4f _sc by dividing the clock by k, and dividing the horizontal scanning pulse by n (where n is a positive value). Integer) to generate a horizontal sync pulse of the solid-state image sensor, and divide the horizontal sync pulse by m (however,
(m is a positive integer) to generate a vertical synchronizing pulse of the solid-state image sensor, an A / D converter for converting a signal output from the solid-state image sensor into a digital signal, and the digital signal A video signal generating circuit for processing the video signal and an electronic zoom signal processing circuit for electronic zooming the video signal so that the screen is enlarged vertically or horizontally by the timing signal. In the generator circuit,
An imaging device characterized in that m and n can be switched under the condition that m × n is constant. 4. The method according to claim 3, wherein n = 750, m = 637 and the frame period is 3
3.37 msec, horizontal sync signal period 52.38 μs
ec, the number of lines per frame is 288, which is the same as in the CIF standard, and a digital video signal in which the number of dots is 720, which is twice the CIF standard, is obtained.