JPH05176213A - Electronic zoom system - Google Patents

Abstract

PURPOSE:To avoid adverse influence onto picture display due to irregular arrangement of scanning lines when an electronic zoom function in a real time is realized in a standard field memory. CONSTITUTION:A frame control means 5 controls write/read of a frame memory 3 so as to obtain a zoom picture interlaced-scanning an odd numbered field and an even numbered field in the same order as an input picture by switching a write/read timing at the odd numbered field and the even numbered field in the unit of a horizontal line to a frame memory 3 based on a synchronous signal extracted from a picture signal by a synchronism separating means 1. An electronic zoom picture in which the order of the odd numbered field and the even numbered field is correctly arranged is obtained by using a standard inexpensive field memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic zoom system for obtaining an electronically zoomed image signal from an input image signal. It is suitable for use as a TV intercom that allows you to take a picture with a TV camera and check the monitor in a house.

[0002]

2. Description of the Related Art A conventional TV intercom has an image pickup range of 60 degrees in horizontal angle and 45 degrees in vertical angle. There was a drawback that you couldn't see it. Therefore, it is possible to widen the image capturing range by setting the lens of the TV camera to a wide angle. A method has been proposed in which a part of an image captured by a lens is electronically zoomed and displayed. In order to realize this electronic zoom, the image of the area to be electronically zoomed may be temporarily stored in a dedicated memory called a frame memory, and then enlarged and read over the entire screen.

In the Japanese television system (NTSC standard), one frame is constructed by interlacing (interlaced scanning) of two fields (a pair of an odd field and an even field). Most of the image pickup means such as CCD and the monitor TV also operate at the timing according to this, so that it is necessary to perform the interlace even when the electronic zoom is performed.

On the other hand, in recent years, an inexpensive standard LSI called a field memory is available, which is shown in FIG.
As shown in FIG. 2, an input line memory Mi composed of a serial memory for one line of input image data and an output line memory Mo composed of a serial memory for one line of output image data are independently provided on the input side and the output side. Thus, the write / read operation is performed on the dynamic memory array Ma of the main body on a line-by-line basis. In this way, since access is performed in units of lines, it is not necessary to write / read high-speed image data one by one, and it is not necessary to use a high-speed internal memory array. If an interlace type electronic zoom function can be realized by using this type of memory, it is advantageous because it can be made inexpensive and simple. For electronic zooming, the image data of the portion to be zoomed may be temporarily stored in the field memory and read out and displayed on the entire screen. However, since this processing needs to be performed in real time, writing of the current frame and reading of the previously written frame must be performed in parallel. Simply, the image data input at the interlace timing is directly input to the field memory, and the image data of one frame before is written just before writing (hereinafter, referred to as “frame unit processing”).
However, when performing the zoom operation, it is necessary to change the location and the timing for writing and reading, which causes inconvenience.

For example, in FIG. 4, when the area Z to be zoomed is zoomed in on the entire screen, the image data of the area Z is fetched into the field memory. The image data for each line of the area Z is input to the input line memory Mi of the field memory shown in FIG. 2 for each pixel, and when the input of one line is completed, the image data is collectively collected in the memory array Ma.
Transfer to. This is performed over the entire region Z to be zoomed, and after one frame time, reading is performed by the reverse operation. At this time, the last pixel L of the area Z to be zoomed
When the timing at which is written is measured from the beginning of one field period to be T (L), it becomes as shown in FIG.
(The current field is assumed to be an odd field, but the same applies to the even field.) The data of this last pixel L is read out in the next frame as shown in FIG. In order to perform the zoom, the timing T ′ (L) at which the pixel L is read out is clearly at the end of the field period. However, at this time, it is necessary to write the data of the zoom area of the next frame in the same field, and if the zoom area does not change, this timing becomes T (L) as in the previous frame. here,
Since the write timing T (L) of the current frame is earlier than the read timing T ′ (L) of the previous frame,
Before reading the data of the previous frame at the timing T ′ (L), the data of the current frame is written at the timing T (L), and the data of the previous frame is erased. Therefore, the electronic zoom cannot be realized by the frame unit processing of reading one frame later.

Next, let us consider a field unit process of reading data written in one field in the next field. 6 to 8 show the manner of field unit processing. FIG. 6A shows an example of an interlaced image in the field t according to the NTSC standard. According to the NTSC standard, the number of scanning lines is determined to be 525, and generally, the scanning line numbers 10 to 262 form an odd field and 273 to 525 form an even field. The other scanning lines are in the blanking period. Since interlacing is performed, the scan lines 273 to 525 in the even field are located between the scan lines in the odd field.
FIG. 6B shows the operation of the field memory. If the electronic zoom is performed, only the zoom area needs to be stored in the field memory, but here, for ease of explanation, the entire area is stored. The image data in the field t is stored in the corresponding memory area, and at the same time, the even field data stored one field before (t-1) is read out. As described above, the data up to the number 525 starting with the number 273 is read in the output image. 7 (d)-
The state of the next field (t + 1) is shown in (f). One frame is configured through FIGS. 6A to 6C and FIGS. 7D to 7F. The output image of FIG. 6C and the output of FIG. A composite image of the images is shown in FIG. The composite image of FIG. 8 (g),
Comparing the input images of the standard frame configurations of FIG. 6A or FIG. 7D, it is apparent that the configurations of the scan lines in the odd field and the even field are reversed. This means that the image is not displayed in the correct configuration, the diagonal lines are jagged, and the moving image is unnatural. In this way, in the simple field unit processing, inconvenience occurs.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to realize a real-time electronic zoom function using a standard field memory. At this time, it is to prevent the scanning lines from being arranged in an incorrect manner and adversely affecting the image display.

[0008]

According to the electronic zoom system of the present invention, in order to solve the above-mentioned problems, in a television system in which an odd field and an even field are interlaced and scanned, as shown in FIG. A sync separation means 1 for extracting a sync signal from an input image signal, an A / D conversion means 2 for digitizing the image signal, a frame memory 3 composed of two field memories, and an output of this frame memory 3. And the D / A conversion means 4 for analogizing the data and the timing of writing / reading in horizontal line units to / from the frame memory 3 based on the synchronization signal are switched between the odd field and the even field to convert the odd field and the even field into the input image. The frame memory 3 is used so that the zoom image to be interlaced and scanned in the same order can be obtained from the frame memory 3.
And a frame memory control means 5 for controlling writing / reading of the data.

Further, as shown in FIG. 2, a television camera 6 equipped with a wide-angle lens and a slave 8 having a microphone 7 for collecting the voice of a visitor, and an image signal and a voice signal from the slave 8 are transmitted. In a television intercom including a signal transmission system 9, a monitor television 10 for displaying an image from the slave unit 8 and a master unit 12 having a speaker 11 for outputting a sound from the slave unit 8, the electronic zoom means having the configuration shown in FIG. It is preferable to provide 13 in the master device 12.

[0010]

The operation of the present invention is shown in FIGS. here,
It is assumed that a field unit process for reading the image data of one field before is performed using a standard field memory. First, in the odd field, as shown in FIG.
As shown in FIG. 9B, while the data in the odd field is stored in the corresponding line of the corresponding field memory, at the same time, as shown in FIG. 9C, the data of the even field stored in the previous field is Read out. At this time, the frame memory control means 5 delays the data of the even field by one line and reads it. In other words, the read operation is not started at the timing of the 10th scanning line, the wait operation is performed, and the data of the even field 273 is read at the timing of the 11th scanning line. In this way, if the reading is delayed by one line, the reading of the last 525th scanning line is not performed. In this way, the position on the screen is moved down by one line as a whole. In this field,
No data is output to the first line, but if data 0 is inserted in this line, it becomes a black level on the screen,
Normally, the monitor TV is overscanned, and it is often not displayed near the boundary of the screen, and even if it is displayed, it will be the same black as blanking, so there is no problem. The next even field operation is read at the same timing as in FIG. 7, without changing the special timing like the odd field. As shown in FIG. 11 (g), the output image synthesized by such scanning becomes equal to the arrangement of regular scanning lines, and the displayed image is also correct.

The above operation can be realized easily and without increasing the cost in the frame memory control means 5, because the odd field read timing is shifted by one line. In order to perform the electronic zoom process, it is sufficient to write only the zoom area at the time of writing in the frame memory 3 and read this out to the entire screen. The order of the arrangement of the scanning lines (the order of the odd / even field scanning lines) is as described above. It suffices to perform similar scanning.

[0012]

FIG. 2 shows the configuration of an embodiment of the present invention. In the present embodiment, for example, in a general house or an apartment house, a face of a visitor can be photographed with a TV camera, and a master unit of a TV intercom that can check a monitor in the house is shown in FIG.
The electronic zoom means 13 having the structure shown in FIG. This TV intercom includes a TV camera 6 equipped with a wide-angle lens and a slave unit 8 having a microphone 7 for collecting a voice of a visitor, a signal transmission system 9 for transmitting an image signal and an audio signal from the slave unit 8, and a slave unit. A monitor TV 10 for displaying an image from the device 8 and a parent device 12 having a speaker 11 for outputting a sound from the child device 8 are used. By using a wide-angle lens, a screen G is displayed as shown in FIG. Although the visitor's face and figure to be projected are relatively small, only the area Z desired to be zoomed is enlarged by the electronic zooming means 13 and projected on the monitor television 10, so that an image of a size that is easy to see can be obtained. Also, regarding the image quality,
As described above, since the odd field and the even field are arranged in the correct order, good image quality can be obtained.

In the electronic zoom means having the configuration shown in FIG. 1, a standard field memory LSI is used as the frame memory 3.
, And divide the internal memory into two, allocate them to the odd and even fields and use them as a frame memory. Also, since writing and reading are performed in parallel,
The electronic zoom function can be realized with one field memory. Further, the sync separation means 1 only needs to be able to separate the horizontal sync signal and the vertical sync signal from the image signal, and can be realized by a general-purpose circuit, so that it can be constructed at low cost. Further, the A / D conversion means 2 and the D / A conversion means 4 can also be configured by using a general-purpose IC. Therefore, in the present invention, the interlaced electronic zoom function can be realized at low cost.

[0014]

According to the electronic zoom method of the first aspect, the timing of writing / reading in horizontal line units to / from the frame memory is switched between the odd field and the even field based on the synchronization signal, thereby changing the odd field and the even field. Since the writing / reading of the frame memory is controlled so that the zoom image obtained by interlaced scanning in the same order as the input image can be obtained from the frame memory, an odd field is generated by using the standard low-cost field memory. There is an effect that it is possible to obtain an electronic zoom image in which the order of the even fields is arranged correctly.

When the electronic zoom system of the present invention is applied to the master unit of a TV intercom equipped with a TV camera using a wide-angle lens, the face and figure of the visitor can be enlarged. You can check with good image quality,
Moreover, there is an effect that an increase in cost can be suppressed to a minimum.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a field memory used in the present invention.

FIG. 4 is an explanatory diagram of a zoom area in a conventional electronic zoom system.

FIG. 5 is a time chart showing the operation of a conventional electronic zoom system.

FIG. 6 is an explanatory diagram of an operation in an odd field period of a conventional electronic zoom system.

FIG. 7 is an operation explanatory diagram of a conventional electronic zoom system during an even field period.

FIG. 8 is an explanatory diagram showing an output image of a conventional electronic zoom system.

FIG. 9 is an operation explanatory diagram of an odd field period of the electronic zoom system of the present invention.

FIG. 10 is an explanatory diagram of an operation in the even field period of the electronic zoom system of the present invention.

FIG. 11 is an explanatory diagram showing an output image of the electronic zoom system of the present invention.

[Explanation of symbols]

 1 sync separation means 2 A / D conversion means 3 frame memory 4 D / A conversion means 5 frame memory control means 6 TV camera 7 microphone 8 slave unit 9 signal transmission system 10 monitor TV 11 speaker 12 master unit 13 electronic zoom unit

Claims (2)

[Claims] 1. In a television system in which an odd field and an even field are interlaced and scanned, a sync separation means for extracting a sync signal from an input image signal, an A / D conversion means for digitizing the image signal, and two sheets of A frame memory composed of a field memory, a D / A conversion means for converting the output of the frame memory into an analog signal, and a timing of writing / reading in horizontal line units to / from the frame memory on the basis of a synchronizing signal is odd field or even field. And a frame memory control unit for controlling writing / reading of the frame memory so that a zoom image in which the odd field and the even field are interlaced and scanned in the same order as the input image can be obtained from the frame memory. Electronic zoom method. 2. A slave unit having a television camera equipped with a wide-angle lens and a microphone for collecting a voice of a visitor,
In the TV intercom consisting of a signal transmission system for transmitting an image signal and an audio signal from the slave unit, a monitor TV for displaying an image from the slave unit and a master unit having a speaker for outputting the sound from the slave unit, the synchronization separation is performed. Means, the A / D conversion means, the frame memory, and the D / A
The master unit is provided with an electronic zoom unit including a conversion unit and the frame memory control unit.
Electronic zoom method described.