JP3321748B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly to an image display device provided with an image conversion processing device for converting an interlaced video signal into a non-interlaced video signal by enlarging it.

[0002]

2. Description of the Related Art In a general television receiver,
An interlace method is adopted in which a video signal of one frame is divided into two odd-numbered and even-numbered field video signals for each scanning line, and the field video signals are alternately scanned and displayed. On the other hand, in a liquid crystal display device or the like, a non-interlaced method that does not perform such interlaced scanning is adopted. Therefore, in order to display an interlaced video signal on a non-interlaced display device such as a liquid crystal display device, see Japanese Patent Application Laid-Open No. 3-25 / 1991.
As described in Japanese Patent No. 8177 or the like, conversion of an interlaced video signal into a non-interlaced video signal is performed. That is, for the odd field and the even field, the adjacent two fields
A video signal of one non-interlaced sequential scanning line is created by adding the video signals of the scanning lines at a predetermined ratio, and a common display element is driven in the odd field and the even field. I have.

[0003]

According to the above-mentioned prior art, no consideration is given to enlarging and converting an image. That is, according to the above-described conventional technology, the number of scanning lines scanned by the non-interlaced display device is determined by the number of scanning lines in a field. For example, the number of scanning lines in one field is 262 or 263. When the input signal of the NTSC system is converted, only about 262 scanning lines are created. Therefore, when the display device is equivalent to the VGA mode of a personal computer, for example, although the number of scanning lines in one field is 480, it is displayed only in a range of about 262 lines, that is, about a half screen area. And the screen of the display device cannot be fully utilized. Therefore, there is a demand for an image processing method for enlarging and converting an interlaced video signal into a non-interlaced video signal.

An image processing method for enlarging and converting a video signal according to an arbitrary enlarging ratio is disclosed in Japanese Patent Laid-Open No. 7-9554.
Although it is described in Japanese Patent Publication No. 0, it is not possible to respond to the above-mentioned request as it is because it converts a non-interlaced video signal into an interlaced video signal. .

A problem to be solved by the present invention is that an interlaced video signal can be enlarged and converted into a non-interlaced video signal in accordance with an arbitrary enlargement ratio, and a display screen can be effectively used.

[0006]

According to the present invention, there is provided an interpolation coefficient generating means for generating an interpolation coefficient based on a set vertical magnification, and an offset value setting means. The set enlargement ratio is w, and the number of the non-interlaced sequential scanning line is n (where n =
(1, 2, 3,...), At least Mo constituting the interpolation coefficient (Mo, No) for the odd field is generated according to the following equation: Mo = (n−1) W + S ₁ − [(n− 1) W + S ₁ ] Here, W = 1−1 / w, [] is a Gaussian symbol for truncating the decimal part, S ₁ is a first offset value. The image conversion means obtains the interpolation coefficient No by the following equation, Interpolation coefficients for even fields (Me, Ne)
No = 1−Mo Me = Mo + S ₂ − [Mo + S ₂ ] Ne = 1−Me where S ₂ is a second offset value, and an interpolation coefficient is selected and selected according to the field of the interlaced video signal. The video signal of the input scanning line immediately before the target input scanning line is multiplied by Mo or Me while sequentially changing the target input scanning line and the interpolation coefficient for each field according to the obtained interpolation coefficient, and the video of the target input scanning line is displayed. The signal is multiplied by No or Ne, and they are added to generate a video signal of the n-th sequential scanning line.
If the change is smaller than Mo or Me used for the 1) th sequential scanning line, the n-th video signal of the same input scanning line as that used for the (n-1) th sequential scanning line is used. This can be solved by generating a video signal of the first sequential scanning line.

That is, basically, the video signals of two adjacent input scanning lines among the input scanning lines are converted into the video signal of one sequential scanning line. At this time, the video signals of the two input scanning lines are multiplied by interpolation coefficients corresponding to the weighting factors, respectively, and added to generate a video signal of one sequential scanning line. By the way, in the case of enlarging an image, the number of scanning lines must be sequentially increased with respect to the input scanning lines. For example, when the magnification in the vertical direction is 6/5 or 8/5, the number of scanning lines must be sequentially reduced to 6 or 8 for 5 input scanning lines. Moreover, in order to eliminate distortion of the enlarged image, it is necessary to maintain a relative relationship between the physical positions of the input scanning lines and the sequential scanning lines on the screen.

Accordingly, the present invention provides a method for enlarging an image with respect to input scanning lines and sequential scanning lines, which are arranged at equal intervals and have different numbers, while maintaining the relative positions of their physical positions. The feature is that the interpolation coefficient is devised as shown in the equation. That is, for example, when eight output scanning lines are created from five input scanning lines, the first and sixth input scanning lines of the odd field and the first and ninth non-interlaced sequential scanning lines are used. The intervals between the scanning lines are sequentially set so that the scanning lines and the scanning lines are located at the same position. Then, the video signals of the two input scanning lines located above and below each of the sequential scanning lines at the set position are added with weights (interpolation coefficients) in accordance with the physical relative positional relationship. That is, the video signals are sequentially scanned. In the case of the same position as the first input scanning line and the first sequential scanning line, the weight coefficient (interpolation coefficient) of the immediately preceding input scanning line is set to 0 (zero). Like that.

Further, since the even field is shifted by 1/2 from the odd field at the interval of the input scanning line, it is necessary to use the physical scanning to form a non-interlaced sequential scanning line from the input scanning line of the even field. In order to match the relative positional relationship, set the offset value to 1/2,
This is added to the weight coefficient (interpolation coefficient) for adjustment. That is, this is a case where the first offset value S ₁ is 0 and the second offset value S ₂ is １ ／.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a configuration diagram of a main part of an image display device according to an embodiment of the present invention. As shown in the figure, the interlaced video signal is temporarily stored in the image memory 1. The video signal stored in the image memory 1 is appropriately read out by the image conversion means 2, enlarged and converted into a non-interlaced video signal, and displayed on a display screen by a display control means (not shown). The conversion condition setting means for variably setting the conversion conditions of the image conversion means 2 includes an enlargement ratio setting means 4, an interpolation coefficient generation means 5,
Offset value setting means 6, adder 7, changeover switch 8
Is formed.

The enlargement ratio setting means 4 supplies an enlargement setting value W corresponding to the enlargement ratio w to the interpolation coefficient generation means 5. The interpolation coefficient generation means 5 creates an interpolation coefficient from the enlargement setting value W in the signal processing for creating a sequential scanning line according to the enlargement ratio and enlarging the video signal.

A method of generating the interpolation coefficient will be described with reference to a specific example shown in FIG. FIG. 3 shows an example in which the interlaced video signal is enlarged 6/5 times in the vertical direction. The relationship between the scanning line positions of the input scanning lines (A) and the sequential scanning lines (B) and the interpolation are shown. The coefficient is shown. In the figure, when an input scanning line as indicated by A (solid line is an odd field, broken line is an even field) is supplied, for example, the first input scanning line 1o is 1 in the odd field.
/ 6 times, and the second input scanning line 2o is multiplied by 5/6 and added to form a sequential scanning line 2m as shown in B. Similarly, 2/6 of the second input scanning line 2o
2/3 times the third input scan line 3o, 3/6 times the third input scan line 3o, and 3/3 times the fourth input scan line 4o.
Six times, 4/6 times of the fourth input scanning line 4o, 2/6 times of the fifth input scanning line 5o, and 5 of the fifth input scanning line 5o.
/ 6 times, 1/6 times of the sixth input scanning line 6o, 0/6 times of the fifth input scanning line 5o, 6/6 times of the sixth input scanning line 6o,... Sequential scanning line 3m,
4m, 5m, 6m, 7m, ... are formed.

In an even-numbered field, for example, the first input scanning line 1e is multiplied by 4/6 and the second input scanning line 2e is multiplied by 2/6 and added, and as shown in FIG. The sequential scanning lines 2m are formed. Similarly,
5/6 times the second input scanning line 2e, 1/6 times the third input scanning line 3e, 0/6 times the second input scanning line 2e, and 6/6 times the third input scanning line 3e. １ ／ times the fourth input scanning line 4e and ／ times the fifth input scanning line 5e.
2/6 times of the fifth input scanning line 5e and 4/6 times of the sixth input scanning line 6e, 3/3 of the fifth input scanning line 5e.
.., 3/6 times the sixth input scanning line 6e,... Are added, and the scanning lines 3m, 4m, 5m, 6m, 7
m,... are formed.

That is, the input scanning lines of the interlaced system have a period of five scanning lines 1o to 5o or 1e to 5e, while the scanning lines have a period of six scanning lines of 1m to 6m. Similarly, conversion is performed, and a non-interlaced video signal obtained by multiplying the input video signal by 6/5 is generated.

Here, the method of forming the sequential scanning lines shown in FIG. 3 will be generalized. First, the interpolation coefficient given to the two input scanning lines of the odd field is (Mo, No), and the interpolation coefficient of the even field is (Me, Ne). Here, Mo and Me are interpolation coefficients applied to the input scanning line immediately before the input scanning line of interest, and No and Ne are interpolation coefficients applied to the input scanning line of interest. In addition, the number of the non-interlaced sequential scanning line is n (where n = 1, 2, 2).
(Natural number of 3 ...), the interpolation coefficient for the n-th sequential scanning line is represented by the following equation.

[0016]

Mo = (n−1) W + S ₁ − [(n−1) W + S ₁ ] No = 1−Mo Me = Mo + S ₂ − [Mo + S ₂ ] Ne = 1−Me where W = 1-1 / W, [] is a Gaussian symbol for truncating the decimal part, S ₁ is a first offset value, S ₂ is a second offset value, 0 ≦ Mo <1, 0 ≦ Me <1, 0 <
No ≦ 1, 0 <Ne ≦ 1, and a small number.

An interpolation coefficient is selected from a sequence of interpolation coefficients obtained in this manner in accordance with the field of the interlaced video signal, and an input scanning line of interest for each field and an interpolation coefficient are selected in accordance with the selected interpolation coefficient. While sequentially changing the coefficient, the video signal of the input scanning line immediately before the input scanning line of interest is multiplied by Mo or Me, the video signal of the input scanning line of interest is multiplied by No or Ne, and they are added. A video signal of the first sequential scanning line is generated. Also, Mo
Or, when Me changes smaller than Mo or Me used for the (n-1) th sequential scanning line, that is, according to the above equation, Mo increases by W as the scanning line advances,
Under the condition of Mo <1, Me <1, if it exceeds 1, the integer part is cut off, and it changes slightly at that time. Then, in that case, the video signal of the n-th sequential scanning line is generated using the same video signal of the input scanning line used for the (n-1) -th sequential scanning line. As a result, it is possible to reasonably generate a video signal related to the sequential scanning line of the enlarged video.

By the way, the above-mentioned interpolation coefficient has a physical meaning that, when the video signals of two input scanning lines are added to generate a video signal of one sequential scanning line, the two input scanning lines are used. This corresponds to the weighting of the line. That is, when enlarging an image, the number of scanning lines must be sequentially increased with respect to the input scanning lines. For example, if the magnification in the vertical direction is 6/5
In the case of double or 8/5, it is necessary to sequentially change the number of scanning lines to six or eight for five input scanning lines.
Moreover, in order to eliminate distortion of the enlarged image, it is necessary to maintain a relative relationship between the physical positions of the input scanning lines and the sequential scanning lines on the screen. Therefore, the image is enlarged while maintaining the relative relationship between the physical positions of the input scanning lines and the sequential scanning lines which are arranged at equal intervals and have different numbers.

For example, when six output scanning lines are created from five input scanning lines, the first and sixth input scanning lines of the odd field and the first and seventh non-interlaced lines are used. The interval between the sequential scanning lines is set so that the scanning lines and the sequential scanning lines are located at the same position. Then, the video signals of the two input scanning lines located above and below each of the sequential scanning lines at the set position are added with weights (interpolation coefficients) in accordance with the physical relative positional relationship. That is, the video signals are sequentially scanned. In the case of the same position as the first input scanning line and the first sequential scanning line in the odd field, the weight coefficient (interpolation coefficient) of the immediately preceding input scanning line is set to 0 (zero). However, the case is not limited to the case of the first input scanning line and the first sequential scanning line of the even field.

Further, since the even field is shifted by 1/2 from the odd field at the interval of the input scanning line, it is necessary to use the physical scanning method to form a non-interlaced sequential scanning line from the input scanning line of the even field. In order to match the relative positional relationship, set the offset value to 1/2,
This is added to the weight coefficient (interpolation coefficient) for adjustment. That is, this is a case where the first offset value S ₁ is 0 and the second offset value S ₂ is １ ／.

More specifically, when 6/5 times shown in FIG. 3 is realized, the interpolation coefficients (Mo, No) given to each input scanning line of the odd field are (0 *, 1), (1/1). 6,5 /
6), (2/6, 4/6), (3/6, 3/6), (4
/ 6, 2/6) and (5/6, 1/6).
What is necessary is just to repeat for every period of one input scanning line. On the other hand, in the even-numbered field, since the barycenter position of the scanning line is shifted, if the video signal of the sequential scanning line at the same position is used as it is, line flicker or the like will occur. As described above, the offset value S ₁ , It has set the S _2. In other words, as shown in FIG. 3, (3/6, 3/6), (4/6,
2/6), (5/6, 1/6), (0 *, 1), (1 /
6, 5/6) and (2/6, 4/6). Further, as can be understood from the figure, when the value of Mo or Me changes small, that is, when the carry-over occurs from the decimal part to the integer part, it is indicated by an asterisk in the coefficient sequence. At this time, the video signal of the next sequential scanning line is created using the same two input scanning lines as the two input scanning lines multiplied by the previous interpolation coefficient.

FIG. 2 shows an example of the interpolation coefficient generating means 5 suitable for generating the interpolation coefficient Mo shown in FIG. In this example,
An enlargement set value W calculated based on the set enlargement ratio w is input to the input terminal 11 from the enlargement ratio setting means 4. Then, the input enlargement setting value W is input to the latch means 13 via the adder 12. The latch unit 13 repeats the latch operation in synchronization with the line clock (clock synchronized with the horizontal synchronization signal of the input video) input to the input terminal 14, and resets the reset signal (such as a vertical synchronization signal) input to the input terminal 22. Reset in synchronism with the signal in the field unit). The output of the latch means 13 is the adder 1
2 has been entered. Because it is formed in this way,
According to the interpolation coefficient generating means 5, the input enlarged set value W
Is added each time a line clock is input, and the added value is sequentially output as a sequence of interpolation coefficients.

By setting the interpolation coefficient Mo output from the latch means 13 to a decimal part excluding the integer part of the addition value, not only 6/5 but also an arbitrary magnification (for example, 8 /
5 times). Also, when a field unit signal such as a vertical synchronizing signal is input to the input terminal 22, resetting is performed for each field even if the field advances one after another, so that the interpolation coefficient of the scanning line at the same position always has the same value. Therefore, the same video state can always be maintained even for the same video signal over a plurality of fields such as a still image.

The interpolation coefficient Mo generated by the interpolation coefficient generation means 5 is supplied to the image conversion means 2 via the changeover switch 8 in the case of an odd field. On the other hand, the offset value S ₂ is the Me being added in the adder 7 to the interpolation coefficient Mo, provided to the image conversion unit 2 via the switch 8 in accordance with the case of the even field. The interpolation coefficient generating means 5 is not limited to the one shown in FIG. 2, but a row of interpolation coefficients is stored in advance in the ROM in association with the enlargement ratio w or the enlargement set value W, and the interpolation ratio w Alternatively, by specifying the enlargement setting value W as an address, a sequence of interpolation coefficients can be sequentially output.

The image conversion means 2 receives the input Mo or M
No, Ne are obtained from the above equations based on e, and interlaced video signals once stored in the image memory 1 are sequentially fetched for each input scanning line in response to changes in the line clock and the interpolation coefficient. Multiplying and adding the interpolation coefficients corresponding to the two input scanning lines, sequentially expanding and converting them into video signals of the scanning lines, and outputting the video signals to display control means (not shown).

With such a configuration, according to the embodiment of FIG. 1, an interlaced video signal can be enlarged and converted into a non-interlaced video signal according to an arbitrary enlargement factor, and the display screen can be displayed. It can be used effectively.

FIG. 4 shows the relationship between input scanning lines and interpolation coefficients when eight output scanning lines are created from five input scanning lines and enlarged using the embodiment of FIG. As shown, the first and sixth input scan lines (1
o, 6o) and the first and ninth non-interlaced sequential scanning lines (1 m, 9 m) are set at the same intervals so that they are at the same position. Then, the video signals of the two input scanning lines positioned above and below each of the sequential scanning lines at the set position are added with interpolation coefficients in accordance with the physical relative positional relationship, and are added. Video signal. Since the enlargement ratio w = 8/5, W = 3/8, and Mo is (0, 3/8, 6 /
8, 1/8 *, 4/8, 7/8, 2/8 *, 5/8), and No is (1, 5/8, 2/8, 7
/ 8, 4/8, 1/8, 6/8, 3/8) are repeated.
Similarly, Me is (4/8, 7/8, 2/8 *, 5/8,
0 *, 3/8, 6/8, 1/8 *) and Ne is (4 /
8, 1/8, 6/8, 3/8, 0, 5/8, 2/8, 7
/ 8) is repeated. And, as understood from the figure, when the value of Mo or Me changes small, that is, when the carry-over occurs from the decimal part to the integer part,
If the coefficient sequence is indicated by an asterisk, a video signal for the next sequential scanning line is created using the same two input scanning lines as the two input scanning lines multiplied by the previous interpolation coefficient. I do.

By doing so, it is possible to expand and convert an interlaced video signal into a non-interlaced video signal in accordance with an arbitrary magnification. FIG. 5 shows a main part configuration diagram of another embodiment of the present invention. The parts shown in FIG. 7 correspond to the conversion condition setting means in FIG. 1, and the parts having the same functions as those in FIGS. A changeover switch 21 and an offset value setting means 23 are newly added, and the interpolation coefficient generating means 20 is modified accordingly.

In the same manner, the set value S ₁ = 0 is supplied from the offset value setting means 23 and the set value S ₂ = １ ／ is supplied from the offset value setting means 3 to the changeover switch 5. The changeover switch 5 selects the terminal a if the field is an odd field and the terminal b if the field is an even field, and supplies the selected offset value to the terminal b of the changeover switch 21 according to the field discrimination signal from the input terminal 16. Here, a field unit signal such as a vertical synchronizing signal is input to the input terminal 22, and the changeover switch 21 is connected to the terminal for a predetermined input scanning line before a field is changed and a video display period starts. By setting the offset value to the b side, the offset value = 0 for an odd field and the offset setting value = １ ／ for an even field.
Supply 3 Next, the signal from the input terminal 22 is switched, and after the changeover switch 21 selects the terminal a, the enlargement set value W is added as the input scanning line advances, as in the embodiment of FIG. , And a sequence of interpolation coefficients Mo similar to that shown in FIG.

As described above, by giving an offset to the interpolation coefficient for each field, when an interlaced video signal is enlarged and further displayed in a non-interlaced manner, regardless of the field, scanning of the correct center of gravity position is performed. Since the lines can be secured, it can be converted into a high-quality enlarged image.

[0031]

According to the present invention, it is possible to convert an interlaced video signal into a non-interlaced display by enlarging the video signal, and to provide a simple configuration of a high-quality video signal without image quality deterioration due to displacement of the center of gravity of a scanning line. Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a main part of an image display device of the present invention.

FIG. 2 is a block diagram showing a specific example of an interpolation coefficient generation unit of FIG.

FIG. 3 is a diagram illustrating a process of enlarging and converting a video signal according to the present invention;
It is a figure explaining taking / 5 times as an example.

FIG. 4 shows an enlargement conversion process of a video signal according to the present invention in 8 steps.
It is a figure explaining taking / 5 times as an example.

FIG. 5 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image memory 2 Image conversion means 4 Magnification rate setting means 5, 20 Interpolation coefficient generation means 6, 23 Offset value setting means 7, 12 Adder 8, 21 Changeover switch 13 Latch means

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takaaki Matino 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within the Visual Information Media Division of Hitachi, Ltd. (72) Inventor Tatsuo Nagata Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa 292 Hitachi, Ltd. Video Information Media Division (72) Inventor Koichi Sudo 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Image Information Systems, Ltd. (58) Fields surveyed (Int.Cl. ⁷ , DB (Name) H04N 7/01

Claims (2)

(57) [Claims] 1. An image display apparatus comprising image conversion means for converting an interlaced video signal into a non-interlaced video signal, wherein an interpolation coefficient is generated based on a set vertical magnification. Generating means and setting means for setting an offset value, wherein the interpolation coefficient generating means sets the enlargement ratio to w, and sets the number of the non-interlaced sequential scanning line to n (where n = 1,
), At least Mo constituting the interpolation coefficient (Mo, No) for the odd field is generated by the following equation: Mo = (n−1) W + S ₁ − [(n−1) W + S ₁ ] where W = 1−1 / w, [] is a Gaussian symbol for truncating the decimal part, and S ₁ is a first offset value.
, And the interpolation coefficient (M
e, Ne), and No = 1−Mo Me = Mo + S ₂ − [Mo + S ₂ ] Ne = 1−Me where S ₂ is the second offset value The interpolation coefficient according to the field of the interlaced video signal Is selected and the video signal of the input scanning line immediately before the input scanning line of interest is multiplied by Mo or Me while sequentially changing the input scanning line and the interpolation coefficient of interest for each field in accordance with the selected interpolation coefficient. The video signal of the input scanning line is multiplied by No or Ne, and they are added to generate a video signal of the n-th sequential scanning line, and Mo or Me is used for the (n-1) -th sequential scanning line. When it is smaller than Mo or Me, the video signal of the n-th sequential scanning line is converted to the video signal of the same input scanning line used for the (n-1) -th sequential scanning line. Image characterized by generating Image display device. 2. The image display device according to claim 1, wherein the first offset value S ₁ is 0, and the second offset value S ₂ is １ ／.