KR970008375B1 - Image stopping and enlarging apparatus of digital image device - Google Patents

Abstract

A device of holding and expanding images in a digital image apparatus having a demodulator 10 for processing an coded input signal to demodulate it into a signal similar to an image signal before coding and to generate a demodulated image, a first frame memory 20 for storing the demodulated image and outputting it by one frame, and a display 30 for displaying the image on a picture is provided which includes a switch for blocking the signal sent from the demodulator to the first frame memory, a memory block 60 for storing a series of image frame signals supplied to the display 30 in order to hold or expand the image being displayed, and a signal expander 50 for expanding the image signal stored in the memory block 60 by a predetermined magnification and sending it to the first frame memory in case of expansion of image signal.

Description

Image freeze and enlargement device of digital video device

BRIEF DESCRIPTION OF THE DRAWINGS Fig. Is a block diagram of an image still and enlargement apparatus of a digital imaging apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

10: decoder 20: first frame memory

30: display device 40: control unit

50 filter 60 second frame memory

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to digital imaging devices, such as video phones and digital televisions, and more particularly to digital imaging devices capable of freezing necessary video scenes and enlarging the scenes to a specific magnification.

Digital video device converts analog video signal into digital signal and processes digital signal, that is, sampled and quantized digital signal by computer or signal processing chip for filter processing, conversion, modulation, demodulation, compression, storage, transformation, etc. It is a device that can process video signal to meet specific purpose by processing of.

Various methods of freezing and enlarging video have been proposed in the currently developing HDTV (High Definition Television) or some digital video telephony devices, but such methods are very complicated and the video freeze and enlargement devices attached by such methods are very complicated. Causes significant price increases for video equipment.

It is therefore an object of the present invention to provide an apparatus for freezing and enlarging an image in a simple manner.

An image still and enlargement apparatus according to the present invention is a decoder for predetermined processing of an encoded signal input through a transmission channel to decode the signal close to an image signal at the time of encoding, and outputs a predetermined decoded image. A digital image device comprising a first frame memory for storing a decoded picture and outputting the frame-by-frame, and a display device for displaying the frame-by-frame picture on a screen, the digital image device being transmitted from the decoder to the first frame memory. A switch means for blocking a signal, a memory block for separately storing a series of image frame signals provided to the display device to freeze or enlarge a displayed image, and located between the memory block and the first frame memory; The memory when the video signal is enlarged Signal expansion means for enlarging the image signal stored in the block at a predetermined magnification and outputting the image signal to the first frame memory; and blocking a signal transmitted from the decoder to the first frame memory by opening a switch means at the time of stopping and enlarging an image And a control unit for controlling the transmission of the image data stored in the memory block to the first frame memory through the signal expansion means and the magnification of the signal expansion means.

Hereinafter, with reference to the accompanying drawings the present invention will be described in detail.

Figure shows an image still and enlargement apparatus of a digital imaging apparatus according to the present invention.

The encoder 10 performs predetermined processing on the encoded signal transmitted and transmitted to the transmission channel, decodes the signal into a signal close to the video signal at the time of encoding, and outputs the decoded image in a predetermined unit. The general decoder 10 includes a buffer used for a general image decoder, a variable length decoder, an inverse quantizer, and an IDCT.

In general, in the transmission of an image as a digital signal, each line of the image frame is defined as a series of digital data bits referred to as " pixels. &Quot; Therefore, a large amount of data is generated to define an image displayed on one screen. In order to transfer that much data over the bandwidth of the currently available transport channel, the data must be compressed. Representative data compression techniques are orthogonal transformations that reduce intraframe correlation such as Discrete Cosine Transform (DCT), and differential signal coding that reduce temporal correlation between frames such as motion compensation.

In the decoder 10, an inverse process of an encoder (not shown) which compresses and encodes data is performed. That is, when a video signal compressed and encoded through a transmission channel is input, the signal is variable-length decoded (variable-length encoding in which the frequency of occurrence of each code is indicated by a short length code and the frequency by a long length code is displayed. Inverse quantization), inverse quantization (the inverse process of quantization that approximates the input image signal as a finite number of values), and IDCT (DCT, which transforms data in the time domain into the frequency domain to reduce intraframe correlation Inverse process of Discrete Cosine Transform) is decoded into a signal close to the video signal at the time of encoding.

The first frame memory 20 stores the decoded image in a predetermined unit and transmits the decoded image to the display device 30. The display device 30 reads data from the first frame memory 20, converts the data into an analog signal for display RGB, and displays the same in a CRT.

The switch SW cuts off a signal transmitted from the decoder 10 to the first frame memory at the time of image stop and enlargement.

The memory block 60 stores a series of image frame signals provided to the display device 30 to provide a still image or an enlarged image at the time of image stop and enlargement. Although not limiting the present invention, three frame signals may be stored in the frame memory block in this embodiment. In the frame memory 1 and the frame memory 3, an INTRA frame (in the present invention, a frame obtained by transcoding and encoding a difference signal obtained by subtracting a motion compensated signal from a current frame during compression encoding is called an INTER frame). Irrespective of the current frame, the frame that transforms and encodes the current frame as it is called an INTRA frame is stored (in the case of the current motion picture expert group (MPEG) method), and a new second intra frame 15 frames after the first intra frame is generated. In the present invention, the second intra frame is stored in the frame memory 1, the first intra frame is stored in the frame memory 3, and the inter frame located in the middle of the two intra frames is stored. Data stored in the memory block 60 is provided to the first frame memory 20 at the time of freezing or expanding the screen.

The filter 50 performs a function of enlarging a still picture and may be implemented as a filter known in the art. In the case of simply freezing, the filter coefficient is 1, and the data output from the frame memory block 60 is transferred to the first frame memory 20 as it is.

The controller 40 "turns off" the switch SW at the time of stopping and enlarging the image to block the signal transmitted from the decoder 10 to the first frame memory 20, and to store the data stored in the memory block 60. Is output to the first frame memory 20 and the screen is enlarged by adjusting the coefficients of the filter when the screen is enlarged.

As shown in FIG. 1, when an image stop signal is input to the controller by the user, the switch SW is opened and the frame data stored in the last frame memory 1 of the three frames, which is entered into the memory block 60, is intra-locked. Transfer to the first frame memory 20. In this case, the user may select frame data stored in the frame memory 2 or the frame memory 3.

The part of the still image that is currently displayed to be enlarged (in the case of 2x magnification, the screen is divided into 4 sections and the user is divided into 4 sections. The size of / 2), and 4 times the magnification, select one of the 16 divisions) and the user inputs a signal for the magnification. Create a new pixel with the average of adjacent pixels. This function is performed in the filter 50. In the case of 2x magnification, the 2x magnification image can be obtained through the process of creating a new pixel by taking 1/2 section on the horizontal axis and the vertical axis of the screen and averaging data between adjacent pixels. For example, if the data value of the first pixel is a and the data value of the second pixel is b among two adjacent pixels, the pixel value created at the center thereof becomes (a + b) / 2. In addition, three new data should be created between two adjacent pixels when zoomed in 4 times. By selecting the area that is 1/4 of the x-axis and 1/4 of the Y-axis centered on the selected part, 4 times magnified image can be obtained. have. For example, when the data value of the first pixel is a and the data value of the second pixel is b among two adjacent pixels, the data values of the three pixels between the first pixel and the second pixel are each (3a / 4 + b / 4), ((a + b) / 2), and (a / 4 + 3b / 4). Since the image magnification toward the vertical is less sensitive to the human eye than the horizontal, the vertical average is not taken to reduce the processing speed. Instead, the same line is displayed again and again.

When the new values set through the enlargement process in the filter 50 as described above are transmitted to the frame memory, a 2x or 4x magnified image is displayed on the display device. 4 times or more (8 times, 16 times, ...) is possible, but deterioration in image quality becomes severe, and in the present invention, the magnification is limited to 4 times.

As a still and enlarged device of a digital imaging apparatus according to the present invention, a desired scene can be stopped and enlarged and viewed.

Claims (2)

A decoder 10 that processes a coded signal input through a transmission channel, decodes it into a signal close to a video signal at the time of encoding, and outputs a predetermined decoded picture; and stores the decoded picture that is continuously output. In a digital image device having a first frame memory 20 for outputting in units of frames and a display device for displaying the image in units of frames on a screen, the digital image device is transferred from the decoder 10 to the first frame memory. A switch means (SW) capable of blocking a signal, a memory block (60) storing a series of image frame signals provided to the display device (30) to freeze or enlarge a displayed image, and the memory block ( 60 and an image scene stored between the first frame memory 20 and the memory block 60 when the image signal is enlarged. Signal expansion means 50 for expanding the arc at a predetermined magnification and outputting the first frame memory; and at the time of stopping and enlarging an image, switching means SW are opened to open the first frame memory from the decoder 10; Transferring the image data stored in the memory block 60 to the first frame memory 20 through the block block signal expansion means 50 of the signal transmitted to the 20, and the magnification of the signal expansion means 50. An apparatus for freezing and enlarging an image of a digital imaging apparatus, characterized in that the control unit 40 controls the control. 2. The image stop and enlargement apparatus of a display video apparatus according to claim 1, wherein the magnification of the signal magnification means is 1 when the image stops.