JP2902670B2 - Display control method - Google Patents

Description

The present invention relates to a display control method for enlargement processing.

(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 to TTC) has standardized the standard for analog still picture videophone devices. The standard screen format for this TTC standard is that the screen must be horizontally long (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) Problem to be solved by the problem However, if the image is enlarged by simply repeating the same pixel data, the display image becomes coarse and the hatched portion becomes step-like. 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, a very clear display image cannot be obtained.

The present invention has been made in view of such a point, and when displaying an image in an enlarged manner, the hatched portion is not stair-shaped, but enables a smooth and relatively natural image to be enlarged and displayed. is there.

(D) Means for Solving the Problems The present invention relates to a display control method for displaying an enlarged image of image data by interpolating data between each pixel data of the image data. Displaying an image, at the position where the simple enlarged image data is re-interpolated, a density difference between pixel data immediately above and pixel data immediately below,
The density difference between the upper left pixel data and the lower right pixel data, and the average value of the pixel data with the smallest density difference among the density differences between the upper right pixel data and the lower left pixel data, as the pixel data to be re-interpolated. Insertion interpolation is performed at the position where re-interpolation is performed, and the enlarged image is displayed again.

(E) Function The pixel data to be interpolated are represented by the density difference between the pixel data immediately above and below the interpolation position, the density difference between the upper left pixel data and the lower right pixel data, the upper right pixel data and the lower left pixel data. By taking the average value of the pixel data having the smallest density difference among the density differences of the pixel data, the interpolation of the pixel data is performed according to the connection of the lines, and the oblique lines are formed as smooth lines without being stepped. Is expressed.

(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 an analog signal fetched in step 1 into digital image data. The A / D-converted image data is used 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 normally expressed in 64 gradations, and image 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 on the front of the apparatus main body as shown in FIG. 4, for example, and is used for viewing a moving image captured by the camera (2) in addition to the power switch (8a). "See" (8b), "Shoot" to make the image a still image (8c), "Send" to transmit the still image (8b)
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 a telephone call by the telephone (10) and transmission of image data to be transmitted to the line.

In the case of the passage by 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, and the telephone line ( The voice signal from 12) is transmitted via the NCU (11) to the telephone (1
0) and a call is made.

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 into 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).

After that, "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 100 lines in mode B), to display on the display (6), one pixel data is quadrupled to 320 pixels x 2
The image data for 00 lines (mode A) 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. In this interpolation processing, the original 100 lines of the image data obtained by simply multiplying the received image data of 160 pixels × 100 lines (mode A) vertically and horizontally by two, that is,
Interpolation processing is performed on data of every other line among the image data (pixel data) stored in the image memory (5).

The control circuit (1) reads the first horizontal 1 from the image memory (5).
The pixel data of the line (320 pixels obtained by overlapping each of the received 160 pixels) is read and stored in the line buffer (13). Further, the next horizontal one line, that is, the next horizontal one line of the pixel data of the received 100 lines is read and stored in the line buffer (13).

The control circuit (1) creates interpolation lines by inserting pixel data to be interpolated between the two lines stored in the line buffer (13) by interpolation processing described below.

For the first pixel and the last pixel (320th pixel) of the interpolation line, the pixel data of the line above it is taken as the pixel data of the corresponding pixel of the interpolation line.

Regarding the other pixels from the second pixel to the 319th pixel, first, the density difference between the pixel data immediately above and the pixel data immediately below the position of the pixel to be interpolated, the pixel data at the upper left and the pixel at the lower right The data density difference and the density difference between the upper right pixel data and the lower left pixel data are calculated. Control circuit (1)
Determines the smallest density difference among the obtained density differences, and sets the average value of the pixel data having the smallest density difference as the pixel data at the position of the pixel to be interpolated. If the density differences are the same or the two are the same, the average value of any of the pixel data having the density differences is used as the pixel data of the pixel to be interpolated. Which pixel data is to be prioritized for the average value is optional, but is, for example, up and down, upper left and lower right, upper right and lower left.

By performing this process for each pixel, one horizontal interpolation line is created.

Further, by performing the same interpolation processing between the received 100 lines, 99 lines can be interpolated. For the last one line, the pixel data of the upper one line, that is, the last line (100th line) of the received 100 lines is used as the interpolation data as it is, and the received 100 lines of pixel data and the generated 100 Since 200 lines of pixel data have been created with the interpolation line, the interpolation processing ends.

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 stores the pixel data of the next horizontal line into a line buffer (1). Read in 13) and perform the following interpolation processing. Then, the data is written into the image memory (5), and the data is sequentially displayed on the display (6). When the interpolation processing of the image data for one screen is completed, the image is enlarged on the display (6). The received image is displayed in a high definition state.

2A to 2C show examples of the state of the interpolation processing. These figures show the state of a part of the image memory that stores the pixel data, and show the state before and after the interpolation processing. Before the interpolation processing, the right side of the broken line is approximately black pixel data, and the left side of the broken line is approximately white pixel data. In addition, black numbers represent interpolated pixel data, and the others represent received pixel data.

In the case of FIG. 2A, Is the average value of the pixel data of Is the average value of the pixel data of Average value of the image data Is the average value of the pixel data. At this time, Is white pixel data, Is black pixel data, and the boundary line (broken line) is a straight line.

In the case of FIG. 2B, Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data. At this time, Is white pixel data, Becomes black pixel data, and the boundary line that has been stepped before the interpolation processing becomes a smooth oblique line.

Similarly, in the case of FIG. 2C, Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data of Is the average value of the pixel data. At this time, Is white pixel data, Becomes black pixel data, and the boundary line that has been stepped before the interpolation processing becomes a smooth oblique line.

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) Effect of the present invention As is apparent from the above description, the present invention provides a method of converting pixel data to be interpolated into a density difference between pixel data immediately above and below the interpolation position, pixel data at the upper left and pixel data at the lower right. By taking the density difference between the pixel data of the pixel data and the average value of the pixel data with the smallest density difference among the density differences between the upper right pixel data and the lower left pixel data, the interpolation of the pixel data according to the connection of the lines can be performed. It becomes possible. As a result, the oblique lines are expressed as smooth lines without being stepped, and the enlarged image is displayed as a relatively smooth and natural enlarged image. In particular, when the image is viewed on a large display such as an external monitor, the roughness of the image is suppressed. Furthermore, after displaying a simple enlarged image in which the same pixel data is repeatedly interpolated, a smooth enlarged image re-interpolated is displayed, so that nothing is displayed during the smooth enlarged image display processing. Can eliminate the operator's anxiety.

[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 the front page (72) Inventor Yoshinori Saito 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-62-68366 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) G09G 5/36

Claims (1)

(57) [Claims] 1. A display control method for displaying an enlarged image of image data by interpolating data between pixel data of image data, wherein a simple enlarged image in which the same pixel data is repeatedly interpolated is displayed. The density difference between the pixel data immediately above and the pixel data immediately below, the density difference between the pixel data on the upper left and the pixel data on the lower right, and the density difference between the pixel data on the upper right and the pixel data on the lower left at the position where the data is reinterpolated. Wherein the average value of the pixel data having the smallest density difference is inserted and interpolated at the re-interpolated position as pixel data to be re-interpolated, and the enlarged image is displayed again.