Television – Basic receiver with additional function – For magnification of part of image
Reexamination Certificate
1998-11-05
2001-02-27
Lee, Michael (Department: 2714)
Television
Basic receiver with additional function
For magnification of part of image
C348S715000
Reexamination Certificate
active
06195131
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of generating an enlarged image signal using a field memory.
2. Description of the Prior Art
A conventional process for electronically enlarging an image signal using a memory is executed as follows. First, image signals for one frame on an input screen are written into a memory. A desired area of the written image signal to be enlarged is designated and read. A process for enlarging the read image signal is executed and the processed image signal is delivered to a monitor so that a corresponding image is displayed.
A field memory simplifies the control since the number of control signals used is small. Accordingly, the field memory is used as the above-described memory in the image signal enlarging process. However, the use of the field memory reveals the following disadvantages. In the field memory, a write address serving as a write location and a read address serving as a read location are sequentially incremented from a start address by a write-in clock (WCLK) and a read-out clock (RCLK) respectively. The write address and the read address can be returned to the start address by respective reset signals. However, a writing operation and a reading operation following the write and read addresses respectively can be executed only by sequential addresses.
Accordingly, when the image signals of one frame written into the field memory is read out so that the image signal of an enlarged area is extracted, the image signal other than the enlarged area needs to be discharged at high speeds. Thus, it is not easy to extract only the image signal of the area to be enlarged during the processing of dynamic images.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a method of generating enlarged image signals using the field memory, which method can overcome the above-described problems and can render the image signal enlarging process easier.
The present invention provides an improved method of generating enlarged image signals in use of field memory. In the method, means is provided for designating an area to be enlarged in an image signal delivered from a video camera. A memory is provided for storing the image signal of the designated area to be enlarged. A memory controller is provided for controlling write and read of the image signal into and from the memory. Signal converting means is provided for converting the image signal read from the memory to a corresponding video image signal. Image display means is provided for displaying an image on a display screen on the basis of the video image signal. An odd-line field memory is provided into which image signals of odd-line fields by the interlaced scanning are written. An even-line field memory is provided into which image signals of even-line field by the interlaced scanning are written. The method comprises the steps of writing the image signals of the odd-line field and the image signals of the even-line field into predetermined buffer areas of the field memories respectively in a two-field period of an n-th field and an (n+1)-th field, and reading into predetermined buffer areas alternately the image signals of the odd-line and even-line fields corresponding to the two frames in a four-field period of following (n−4)-th to (n−1)-th fields, thereby generating image signals corresponding to one frame of an enlarged screen, writing the image signals of the odd-line field and the image signals of the even-line field into predetermined buffer areas of the field memory respectively in a two-field period of following (n+2)-th and (n+3)-th fields, and reading into predetermined buffer areas alternately the image signals of the odd-line and even-line fields corresponding to the two frames in the two-field period of the n-th and (n+1)-th fields, thereby generating image signals corresponding to one frame of the enlarged screen, and writing the image signals of the odd-line field and the image signals of the even-line field into predetermined buffer areas of the field memory respectively in a two-field period of (n+4)-th and (n+5)-th fields, and reading into predetermined buffer areas alternately the image signals of the odd-line and even-line fields corresponding to the two frames in the two-field period of the n-th and (n+1)-th fields, thereby generating image signals corresponding to one frame of the enlarged screen, the above-described steps being repeated.
According to the above-described method, the two field memories are used so that the image signals of the odd-line and even-line fields of previously designated areas to be enlarged are written into the respective field memories and buffered. The image signals are read from the start every one line to thereby be generated into enlarged image signals. This eliminates the image signal processing, for example, discharging at high speeds unnecessary image signals other than the area to be enlarged. Consequently, the process of enlarging the image signals by using the field memories can be rendered easier and storage capacities of the memories can be reduced. Furthermore, the above-described processing cycle for enlarging the image signals of the n-th to (n+5)-th fields is repeated so that a buffer structure suitable to the field memories can be composed and the image signal enlarging process can be executed with use of the memories of smaller storage capacities.
In the above-described method, the enlarged area designating means preferably designates a range of the image signals horizontally and vertically on the basis of horizontal and vertical synchronizing signals. Consequently, any area on the display screen can be designated as the area to be enlarged and accordingly, the image signal enlarging process can be rendered easier.
Furthermore, the enlarged area designated by the enlarged area designating means is sequentially changed. An enlarged image can be scrolled on the display screen. Additionally, the enlarged area designated by the enlarged area designating means is sequentially changed on the basis of the enlarged area designating signals delivered from a microcomputer. Consequently, the enlarged image can be scrolled quickly on the display screen.
REFERENCES:
patent: 4891702 (1990-01-01), Nakayama et al.
patent: 5396298 (1995-03-01), Hosokawa et al.
patent: 5781244 (1998-07-01), Hirose et al.
patent: 5940146 (1999-08-01), Sakaguchi et al.
Elmo Co., Ltd.
Koda & Androlia
Lee Michael
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