JP2840290B2 - Enlargement processing method - Google Patents

Description

The present invention relates to an image enlargement processing method.

(B) Conventional technology In recent years, a videophone device for transmitting a still image using a communication line such as a subscriber line has been developed and put into practical use (for example, "Electronic Life" published by Japan Broadcasting Publishing Association, 1988 (See the August issue article "Unification of Still Image Video Phone Planning Based on the TTC Standard Method.")

The Telegraph and Telephone Technical Committee (abbreviated as TTC) has standardized the standard for analog still picture videophone devices. The standard screen format for this TTC standard system is a mode in which the screen is landscape (160 pixels x 100 lines). A. The screen is portrait (96
There is a mode B of (pixel × 100 lines).

Since the display screen is very small in the size of mode A (or mode B) as it is, usually, the data of one pixel is repeated twice in the horizontal direction and twice in the vertical direction (the same line is repeated twice). Pixel data, 320 for Mode A
The image is displayed as an image of pixels × 200 lines (192 pixels × 200 lines in mode B).

(C) Problems to be solved by the problem However, if the image is enlarged by simply repeating the same pixel data, the displayed image becomes coarse. In particular, when the image is displayed on a relatively large screen such as an external monitor, the roughness appears remarkably.

Further, even if the image is enlarged by taking the average value of the densities of adjacent pixels, the entire image is blurred, and a very clear display image cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and is intended to enlarge an image as a clear image when performing an enlargement process.

(D) Means for Solving the Problems According to claim 1 of the present invention, there is provided an enlargement processing method for performing enlargement processing of image data by interpolating data between pixel data of image data, and If the detected density difference is larger than a predetermined value, data having the same value as one of the adjacent pixel data is detected, and the detected density difference is set to a predetermined value. In the following cases, the average data of the adjacent pixel data is inserted and interpolated between the adjacent pixel data to enlarge the image data.

In the second aspect, the above-described detection of the density difference between adjacent pixel data of the image data and insertion interpolation of the data are performed on the pixel data in the horizontal direction and also on the pixel data in the vertical direction.

(E) Function Since the data to be interpolated is set to the average value of the pixel data or the value of one of the pixel data depending on the density difference between adjacent pixel data, a relatively clear enlarged image can be obtained.

(F) Embodiment FIG. 3 is a schematic configuration diagram of a videophone device according to an embodiment of the method of the present invention.

(1) a control circuit for interpolating received image data using a line buffer (13) and controlling the entire apparatus, and (2) a camera as an imaging means for capturing an image using an image sensor such as a CCD. , (3) is the camera (2)
A / D converter for converting the analog signal fetched in step 1 into digital image data. The A / D-converted image data is stored as storage means via a gate circuit (4) controlled by a control circuit (1). Is stored in the image memory (5).

In this image memory (5), each pixel is usually expressed in 64 gradations, and pixel data of at least 320 pixels × 200 lines is stored.

(6) is a display as a display means such as a CRT or a liquid crystal panel capable of displaying an image of at least 320 pixels × 200 lines, and (7) is stored in the image memory (5) under the control of the control circuit (1). A display control circuit for reading the read image data and displaying a video image based on the read image data on a display (6).

(8) is a switch circuit provided with a plurality of switches for causing the control circuit (1) to determine an image captured from the camera (2) as a still image, or to issue an operation command such as transmission of a still image. The switch of the switch circuit (8) is disposed, for example, as shown in FIG. 4 on the entire surface of the apparatus main body. In addition to the power switch (8a), a "view" for viewing a moving image captured by the camera (2) is provided. (8b), “Shoot” to convert the image into a still image (8c), “Send” to transmit the still image (8
d) The display on the display (6) is displayed on the camera (2)
The "own / other party" (8e) is provided to switch between the image captured in step 2 and the image transmitted and received from another videophone device.

(9) is a modem as transmission means for modulating image data to be transmitted or demodulating received image data.

(10) is a telephone set provided separately from the videophone device, and is connected to the videophone device by a network control circuit (hereinafter referred to as NCU) (11). The NCU (11) is connected to a telephone line (12), and controls switching between connection of an audio signal for communication by the telephone (10) and transmission of image data to the line.

In the case of a telephone call with the telephone (10), the voice signal from the telephone (10) is transmitted to the telephone line (12) via the NCU (11) while the telephone line with the telephone of the other party is secured. The voice signal from 12) is transmitted via the NCU (11) to the telephone (1
0) and a call is made.

Now, in this apparatus, the camera (2) captures image data of 320 pixels × 200 lines while the power is turned on, regardless of whether the telephone line with the other apparatus is secured. Will be

Image data of analog signal from camera (2) is A / D
The data is digitized by the converter (3) and written to the image memory (5) through the gate circuit (4).

The image data written in the image memory (5) is read out by the display control circuit (7), and an image based on the image data is displayed on the display (6). At this time, on the display screen of the display (6), a mirror image is displayed in which the left and right sides of the image captured by the camera (2) are reversed. Since writing and reading of image data are performed instantaneously, the image is displayed as a moving image.

In the case of transmitting image data, a switch circuit (8) is first used in order to convert a video displayed on the display (6) as a still image into a still image while a line with the other party's videophone device is secured. ) Is pressed to instruct the control circuit (1) to control the gate circuit (4) to stop inputting image data to the image memory (5) (or Even if you press "Send" (8d) directly without pressing "Shoot" (8c), the movie is fixed as a still image).

The control circuit (1) closes the gate circuit (4) to prevent image data from being input to the image memory (5). As a result, the image data is fixed on the image memory (5), and a still image is displayed on the display (6).

Then, "Send" (8d) is operated. (Pressed)
And the control circuit (1) reads out the image data fixed in the image memory (5) in a predetermined order, modulates it with the modem (9), and sends it to the telephone line (12) via the NCU (11). Send out.

Similarly, when "Send" (8d) is directly operated without pressing "Shoot" (8c), the image data is fixed in the image memory (5), and the moving image becomes a still image. The image data is read from the image memory (5) and transmitted by the modem (9).

Image data sent from other videophone devices
The data is received and demodulated by the modem (9) via the NCU (11) and stored in the image memory (5). At this time, the control circuit (1)
Is 160 pixels x 100 if the received image data is mode A
Since there is only line image data (96 pixels x line in mode B), one pixel data is multiplied by 4 to 320 pixels x 200 lines (mode A) to display on the display (6) for the time being. The data is stored in the image memory (5).

The display (6) displays the received images sequentially as the image data (pixel data) is stored in the image memory (5). The image displayed on the display (6) is a coarse image because the received image data is simply enlarged.

Therefore, when the reception of the image data for one screen is completed, the control circuit (1) automatically re-interpolates the image data.

The interpolation processing of the method of the present invention will be described with reference to FIGS. This interpolation processing is performed only for the received image data of 160 pixels × 100 lines (mode A). That is, of the image data (image data) stored in the image memory (5), the interpolation processing is performed on the data of every other pixel and every other line.

The control circuit (1) reads the pixel data of the first horizontal line (160 pixels) from the image memory (5) and stores it in the line buffer (13).

Then, the control circuit (1) calculates the gradation difference (density difference) between the read pixel data and the adjacent pixel data, and calculates a predetermined value (here, 16 gradations, the total number of gradations). 4
If it is larger than (approximately 1 / approximately), the tone value of one of the pixel data (here, the left side) is inserted and interpolated as pixel data for interpolating between the pixel data and the pixel data for which the tone difference has been obtained. If the obtained gradation difference is equal to or smaller than a predetermined value (16 gradation differences), the average gradation value of the pixel data for which the gradation difference has been calculated is calculated, and the average value (gradation value) is calculated. Is inserted and interpolated as pixel data for interpolating between the calculated pixel data and.

This state is represented by a pixel of the received image data, a pixel having the average gradation value of the neighboring pixel data when the gradation difference between the neighboring pixel data is equal to or less than a predetermined value, and a symbol ◎ representing the neighboring pixel data. FIG. 2A shows an example of a pixel having the same gradation value as the pixel data on the left side when the gradation difference is larger than a predetermined value.

When the interpolation of pixel data for the first line is completed, the second line (the second line out of 100 lines) is read out from the line buffer (13), and the same interpolation processing is performed as shown in FIG. .

Next, in the two lines subjected to the interpolation processing, the gradation difference is similarly obtained for the pixel data adjacent in the vertical direction, and is compared with a predetermined value to perform the interpolation processing. In the pixel data inserted by this interpolation processing, a line like B in FIG. 2 is inserted as a new line between one line and two lines.

When the vertical (vertical) interpolation processing is completed, the next horizontal line is read out to the line buffer (13), and the same interpolation processing is performed, and then the vertical interpolation processing is performed again. This process is repeated until the interpolation process is completed for one screen of image data.

In the above interpolation processing, the control circuit (1) stores the processed line at an appropriate position in the image memory (5) every time one line of the interpolation processing is completed, and the data is written into the image memory (5). Are sequentially displayed on the display (6). When the interpolation processing of the image data for one screen is completed, the enlarged received image is displayed on the display (6) in a high definition state.

In this embodiment, the received image data is simply enlarged once, stored in the image memory (5), and displayed.
There is no particular necessity, and the received image data may be sequentially interpolated, stored directly in the image memory (5), and displayed on the display (6).

(G) Effects of the Invention As is clear from the above description, the present invention changes the data to be inserted and interpolated according to the gradation difference between adjacent pixel data. It becomes a fine image. In particular, when a received image is viewed on a large display such as an external monitor, the roughness of the image is suppressed.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining the operation of one embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of one embodiment of the present invention,
FIG. 3 is a schematic configuration diagram of a videophone device according to one embodiment of the present invention, and FIG. 4 is a schematic front view of the videophone device according to one embodiment of the present invention. (1) Control circuit (2) Camera (3) A /
D converter, (4) gate circuit, (5) image memory, (6) display, (7) display control circuit, (8) switch circuit, (8b) ... " to see",
(8c)… “Shoot”, (8d)… “Send”, (9)…
Modem, (10)… Phone, (11)… NCU, (12)…
... telephone line, (13) ... line buffer.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yoshinori Saito 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-62-154880 (JP, A) JP-A Sho 64-11476 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H04N 7/14

Claims (2)

(57) [Claims] In an enlargement processing method for performing enlargement processing of image data by interpolating data between respective pixel data of image data, a density difference between adjacent pixel data of the image data is detected, and the detected density difference is determined to be a predetermined value. When the detected density difference is equal to or less than a predetermined value, the average data of the adjacent pixel data is obtained when the detected density difference is equal to or less than a predetermined value. An enlargement processing method characterized by performing enlargement processing of image data by inserting interpolation between adjacent pixel data. 2. The method according to claim 1, wherein the detection of the density difference between the pixel data adjacent to the image data and the interpolation of the data are performed on the pixel data in the horizontal direction and also on the pixel data in the vertical direction. 1. The enlargement processing method according to 1.