JPH10274962A - Video correction circuit for display device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent deterioration of corrected image quality due to noise or fluctuation of an image. SOLUTION: In a PDP displaying a multi-tone image by a subfield method, a motion vector detecting unit 10, a motion vector delay unit 18 for obtaining a motion vector of each pixel within a set range S including a target pixel, A counting unit 22 that counts the number of pixels having a motion vector, a comparison unit 24 that compares the count value K with a set value Q, and a setting when there is no motion vector of the pixel of interest by the detection unit 10 and there is an output from the comparison unit 24. A burying unit 28 that outputs a motion vector of a predetermined pixel (eg, a left neighboring pixel) in the range S as that of a target pixel, and outputs a signal in which a display position of each subfield of the target pixel is corrected by the motion vector to a PDP. Even if the motion vector of the pixel of interest e, which should be originally detected by the detection unit 10, is not detected due to noise or fluctuation of the video, a predetermined image within the set range S is provided. The moving image of the pixel of interest e can be corrected with the elementary motion vector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention time-divides one frame into a plurality of subfields (or subframes) and emits light in subfields corresponding to the luminance level of an input video signal to display a multi-tone image. The present invention relates to a moving image correction circuit of a display device.

[0002]

2. Description of the Related Art As a thin and lightweight display device,
PDPs (plasma displays) and LCDs (liquid crystal displays) have attracted attention. The driving method of this PDP is
This is completely different from the conventional CRT driving method, and is a direct driving method using a digitized input video signal. Therefore, the luminance gradation emitted from the panel surface is determined by the number of bits of the signal to be handled.

[0003] PDPs are AC type and D type having different basic characteristics.
It is divided into two types of C type. In the AC type PDP, sufficient characteristics have been obtained with respect to luminance and life, but there have been only reports on gradation display up to 64 gradation display at the prototype level. However, the address / display separated driving method (A
(DS subfield method) has been proposed in the future with 256 gradations. FIGS. 4A and 4B show a driving sequence and driving waveforms of the PDP used in this method.

In FIG. 4A, for example, 8 bits,
In the case of 256 gradations, one frame has a relative luminance ratio of 1,
Eight subfields SF1, SF2, SF3, SF4, SF5, S of 2, 4, 8, 16, 32, 64, 128
The display is composed of F6, SF7, and SF8, and displays 256 gradations by combining the luminances of eight screens.

In FIG. 4B, each subfield is composed of an address period in which data for one refreshed screen is written and a sustain period for determining a luminance level of the subfield. In the address period, first, wall charges are initially formed on each pixel at the same time for the entire screen, and then a sustain pulse is applied to the entire screen to perform display. The brightness of the subfield is proportional to the number of sustain pulses and is set to a predetermined brightness. In this way, 256 gradation display is realized.

[0006]

The moving image correction circuit of the display device of the address / display separation type driving system as described above has conventionally been configured as shown in FIG. That is, the motion vector detecting unit 10 detects a motion vector of a pixel (for example, a moving pixel) in one or more frames based on a video signal input to the input terminal 12, and the moving image correction unit 14 detects the motion vector. The video signal input to the input terminal 12 is corrected based on the value (motion vector), and the corrected video signal is output to the PD via the output terminal 16.
P (not shown), and corrects the display position of each subfield of the pixel of interest to perform moving image correction.

However, in the conventional example shown in FIG.
Since only the motion vector is detected for the target pixel to be processed and the motion of the target pixel is corrected based on the detected motion vector, the image quality is degraded due to noise or fluctuation of the video signal (video data). There was a problem that there was. That is, when there is actually a motion vector, but erroneously detects that there is no motion vector due to noise or fluctuation of the video signal,
Since different moving image corrections are performed for the pixel of interest detected when there is no motion vector and for peripheral pixels detected that there is a motion vector, there is a problem that the moving image correction may adversely degrade image quality.

For example, as shown in FIG. 6, in a moving image portion including nine pixels a to i (3 × 3), the motion vector detecting section 10 detects c, c, which are affected by noise or fluctuation of a video signal. For the three pixels e and i, no motion vector is detected (no motion vector is detected), and the remaining a, b, d, f, g, and h are not affected by noise or fluctuation of the video signal.
If the motion vectors are detected (displayed by hatching in the figure) for the six pixels, the detected motion vectors become worm-like. In such a case, the moving image correction for improving the image quality is performed for the six pixels a, b, d, f, g, and h for which the motion vectors have been detected. Since the moving image correction is not performed on the pixels, there is a problem that the image quality is deteriorated by the moving image correction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. One frame is time-divided into a plurality of subfields, and a subfield corresponding to the luminance level of an input video signal is emitted to emit a multi-tone image. When the motion vector detecting unit does not detect the motion vector of the pixel of interest due to noise or fluctuation of the video signal (in the case of detecting that there is no motion vector of the pixel of interest) in a display device displaying It is an object of the present invention to provide a moving image correction circuit that can prevent the image from being deteriorated.

[0010]

According to the first aspect of the present invention, a moving image correction circuit divides one frame into a plurality of subfields, emits a subfield corresponding to a luminance level of an input video signal, and performs multi-gradation. In a display device for displaying an image, a motion vector detecting unit for detecting a motion vector of a pixel in one or a plurality of frames based on an input video signal, and a motion vector for each pixel in a set range S including a target pixel and peripheral pixels. A motion vector delay unit for obtaining a motion vector by the detection unit, a motion vector number counting unit for counting the number of pixels detected as having a motion vector among all pixels in the set range S, and a motion vector number counting unit A count value comparison unit that compares whether or not the count value of the unit is equal to or greater than a set value, based on outputs of the motion vector delay unit and the count value comparison unit. A motion vector embedding unit that outputs a target vector, and a moving image correction unit that outputs a signal obtained by correcting the display position of each subfield of the pixel of interest based on the motion vector output from the motion vector embedding unit to a display device. Equipped, the motion vector reclaiming part has no motion vector of the pixel of interest obtained by the motion vector delaying part,
Also, when the count value comparing unit is outputting the comparison signal, the motion vector of the pixel having the motion vector within the set range S is output as the motion vector of the pixel of interest, and the motion vector delay unit calculates the motion vector at other times. The motion vector of the noted pixel is output as it is.

The movement direction (for example, the upward direction of the screen) and the movement amount (for example, 5 dots per frame) of a pixel (for example, a moving pixel) between one or a plurality of frames are detected by the motion vector detecting unit (that is, the motion vector). Is detected). The motion vector delay unit obtains a motion vector for each pixel within the set range S (for example, 9 pixels of 3 × 3), and the motion vector count unit detects that there is a motion vector among all the pixels within the set range S. The number of pixels subjected to the counting is counted, and the counted value is compared with a set value in a counted value comparing unit. When there is no motion vector of the pixel of interest obtained by the motion vector delay unit and the count value comparison unit outputs the comparison signal, the motion vector embedding unit sets the motion vector of the pixel having the motion vector within the set range S. Is output to the moving image correction unit as the motion vector of the pixel of interest. That is, even when there is no motion vector of the pixel of interest, if the number of pixels having the motion vector within the setting range S is equal to or larger than the set value, the motion vector of the pixel of interest is filled up with the motion vector of the pixel having the motion vector (replacement). Is).
For this reason, even when it is detected that there is no motion vector due to noise or fluctuation of a video signal even though there is actually a motion vector, it is possible to prevent image quality from being deteriorated by moving image correction by the moving image correction unit.

According to a second aspect of the present invention, in order to make it easy to specify a motion vector to be buried in the motion vector burying section, peripheral pixels within the set range S are prioritized and counted. When the comparing unit outputs a comparison signal and the motion vector detecting unit detects that there is no motion vector of the pixel of interest, the motion vector of the pixel with a high ranking among the pixels having the motion vector within the setting range S is focused on. Fill the motion vector of the pixel.

According to a third aspect of the present invention, in the first aspect of the present invention, in order to easily specify a motion vector to be buried in the motion vector burying section, the count value comparing section outputs a comparison signal and the motion vector is detected. When the unit detects that there is no motion vector of the pixel of interest, the motion vector of the pixel of interest is filled up with the average value of the motion vectors of the pixels having the motion vector within the setting range S.

According to a fourth aspect of the present invention, in order to simplify the configuration of the motion vector delay unit, the pixels within the set range S are set from the target pixel and the surrounding eight pixels. 9 pixels (3 × 3 pixels).

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a moving image correction circuit of a display device according to the present invention.
In FIG. 1, the same parts as those in FIG. In FIG. 1, reference numeral 10 denotes a motion vector detection unit. The motion vector detection unit 10 detects a pixel (for example, a moving image) in one or a plurality of frames based on a video signal (for example, an n-bit digital signal) input to an input terminal 12. ) Is detected and output. For example, based on video signals of the current frame and the previous frame, a motion vector of a moving pixel of the current frame screen in the PDP is detected and output.

Reference numeral 18 denotes a motion vector delay unit which, based on the motion vector output from the motion vector detecting unit 10, sets a set range S (for example, 3 × 3 pixels) of a pixel of interest and peripheral pixels. It is configured to output a motion vector for each pixel within (9 pixels). For example, as shown in FIG. 2, six one-dot delay elements D to D and two one-line delay elements LM, LM are combined, and based on the motion vector input to the input terminal 20, (A), (b) and the pixel of interest e shown in FIG.
Then, a motion vector of each pixel within a set range S (9 pixels of 3 × 3) including the pixels a, b, c, d, f, g, h, and i is output. The one-dot delay element D is constituted by a D-FF (flip-flop), and the one-line delay element LM is constituted by a line memory.

Reference numeral 22 denotes a motion vector number counting unit. The motion vector number counting unit 22 includes the motion vector delay unit 18.
Is configured to count the number of pixels detected as having a motion vector among all the pixels a to i in the setting range S based on the motion vector output from the, and output a count value K thereof. I have. Numeral 24 denotes a count value comparison unit. The count value comparison unit 24 compares the count value K by the motion vector number counting unit 22 with a set value Q input to a set value input terminal 26, and compares when K ≧ Q. It is configured to output a signal (for example, an H level signal).

Reference numeral 28 denotes a motion vector embedding unit. In the motion vector embedding unit 28, the count value comparing unit 24 outputs a comparison signal (for example, an H level signal), and outputs from the motion vector delay unit 18. When there is no motion vector of the pixel of interest e (that is, when the motion vector detection unit 10 detects that there is no motion vector of the pixel of interest e), a pixel having a higher priority among pixels having a motion vector within the set range S Is output as the motion vector of the target pixel, and the motion vector of the target pixel e output from the motion vector delay unit 18 at other times is output. For example, the setting range S is as shown in FIG.
(B) and 9 pixels shown in FIG. 6, pixels having a motion vector are represented by hatched a, a in FIG. 3 (a) and FIG.
Assuming b, d, f, g, and h, the pixels a, b, c, d, f, g, h, and i other than the pixel of interest e are ranked in advance (for example, d, f, b, h, a , C, g, i)
Then, a motion vector of a pixel with a high ranking (for example, pixel d) among the pixels a, b, d, f, g, and h having a motion vector is output as a motion vector of the pixel of interest e.

Reference numeral 14 denotes a moving image correction unit.
Outputs a signal obtained by correcting the display positions of the n subfields SFn to SF1 of each frame of the pixel of interest based on the motion vector output from the motion vector embedding unit 28 to the PDP via the output terminal 16. It is configured to be. For example, in the case shown in FIG. 3A and FIG. 6, based on the motion vector (for example, the motion vector of the pixel d) output from the motion vector embedding unit 28, n of each frame of the target pixel e Subfields S
A signal obtained by correcting the display positions of Fn to SF1 is output to the output terminal 16
And output to the PDP.

Next, the operation of FIG. 1 will be described with reference to FIGS. 2 and 3. For convenience of description, as shown in FIGS. 3A and 3B, the setting range S is made up of a target pixel e to be processed and its surrounding pixels a, b, c, d, f, g, h, and i. 3x
3, 9 pixels, and d, f, b,
A case will be described in which priorities are determined in the order of h, a, c, g, and i, and the set value Q of the count value comparison unit 24 is set to 5.

(1) The motion vector detecting section 10 detects a motion vector (moving direction and moving amount) of a moving pixel in one or a plurality of frames based on an n-bit video signal input to the input terminal 12, and The vector delay unit 18 outputs the motion vectors Ma to Mi for the pixels a to i within the setting range S based on the motion vectors output from the motion vector detection unit 10. Motion vector number counting unit 22
Calculates the number of pixels detected as having a motion vector among all the pixels a to i in the set range S based on the motion vector output from the motion vector delay unit 18, and calculates the count value K. Output.

For example, as shown in FIG. 3A, pixels having a motion vector (a, b, d, f, g, h) is 6
In this case, the count value K output from the motion vector number counting unit 22 is 6 (K = 6), and pixels having motion vectors (c, hatched,
When d, f, h) is 4, the count value K output from the motion vector number counting unit 22 is 4 (K = 4).

(2) No motion vector of the pixel of interest e (Me
= 0) and K = 6 ((a) in FIG. 3), K ≧ Q
Since (Q = 5), the count value comparing section 24 outputs a comparison signal (for example, outputs an H level signal). For this reason, the motion vector embedding unit 28 determines the motion vector Md of the pixel d having the highest priority among the pixels a, b, d, f, g, and h having the motion vector in the set range S as the pixel of interest e. Output as motion vector. That is, the motion vector Me (= 0) of the pixel of interest e is filled up with the motion vector Md of the pixel d.

(3) Based on the motion vector Md buried by the motion vector burying unit 28, the moving image correcting unit 14 performs the n subfields SFn to SF1 of the pixel of interest e.
The signal corrected for the display position of
Output to DP. For this reason, even when the motion vector of the pixel of interest e that should be originally detected by the motion vector detection unit 10 is not detected due to noise or fluctuation of the video signal (Me = 0), the motion vector embedding unit 28 does not. Based on the filled-in motion vector Md, the display positions of the n sub-fields SFn to SF1 of the target pixel e are corrected.

(4) No motion vector (Me
= 0) and K = 4 ((b) in FIG. 3), K <Q
Since (Q = 5), the count value comparison unit 24 does not output a comparison signal (for example, outputs an L level signal). For this reason, the motion vector reclaiming unit 28
(= 0) is output as the motion vector of the pixel of interest e as it is. That is, the motion vector Me (=
0) cannot be filled up with the motion vectors of the peripheral pixels. Therefore, the display positions of the subfields SFn to SF1 of the target pixel e are not corrected by the moving image correction unit 14.

(5) The motion vector of the pixel of interest e is present (Me
In the case of (≠ 0), the motion vector embedding unit 28 outputs this motion vector Me as the motion vector of the pixel of interest e, regardless of the value of K. That is, when Me ≠ 0, the motion vector of the target pixel e is filled with the motion vectors of the peripheral pixels regardless of whether the count value comparison unit 24 outputs the comparison signal (regardless of the H and L level signals). I can't. For this reason, the moving image correction unit 14
A signal in which the display positions of the n subfields SFn to SF1 of the pixel of interest e are corrected based on e (≠ 0) is output to the PDP via the output terminal 16, and the signals of the subfields SFn to SF1 of the pixel of interest e are corrected. The display position is corrected.

In the above-described embodiment, the peripheral pixels in the set range S are ranked in advance, and there is no motion vector (Me = 0) of the target pixel e and the motion vector is buried by the motion vector burying unit. Then, as the motion vector to be reclaimed, a motion vector (for example, Md) of a pixel with a high ranking among pixels having a motion vector within the setting range S is adopted, but the present invention is not limited to this. For example, the absence of a motion vector (Me = 0) of the pixel of interest e may be filled up by the average value of the motion vectors of the pixels having the motion vector within the setting range S.

For example, in the case of FIG. 3A, the motion vectors Ma, Mb, Md, Mf, Mg, Mh of the pixels a, b, d, f, g, and h having the motion vectors within the set range S. May be obtained by the following equation (1), and the absence of a motion vector (Me = 0) of the pixel of interest e may be filled with the average value Mm. Mm = 1/6 (Ma + Mb + Md + Mf + Mg + Mh) (1)

In the above embodiment, the case where the set value Q of the count value comparing section is 5 has been described, but the present invention is not limited to this.

In the above-described embodiment, the case where the setting range S is 9 pixels (3 × 3 pixels) including the target pixel and its surrounding 8 pixels has been described. However, the present invention is not limited to this. It can be used for the case where S is N × M pixels. For example, the present invention can also be applied to a case where the setting range S is 25 pixels (5 × 5 pixels) including a target pixel and 24 peripheral pixels.

In the above embodiment, the case where the display device is a PDP has been described. However, the present invention is not limited to this, and the digital display device (for example, LC
It can be used for the case D).

[0032]

The moving image correction circuit according to the first aspect of the present invention
A motion vector detecting unit, a motion vector delaying unit, a motion vector number counting unit, a count value comparing unit, a motion vector embedding unit, and a moving image correcting unit are provided, and a motion vector for each pixel within the set range S is obtained. The number of pixels detected as being present is counted, and whether the count value K is equal to or greater than the set value Q is compared, this comparison signal is output (for example, an H level signal is output), and the target pixel is output. Is the motion vector of the pixel having the motion vector within the setting range S when the motion vector is absent (Me = 0), the display position of the n subfields SFn to SF1 of the pixel of interest is corrected using the motion vector of the pixel of interest as the motion vector of the pixel of interest. It was configured to be. For this reason, even when the motion vector that should be originally detected by the motion vector detection unit is not detected due to noise or fluctuation of the video signal (Me = 0), the motion vector (for example, Md), the display positions of the n sub-fields SFn to SF1 of the target pixel e can be corrected, the variation between the target pixel and its surrounding pixels can be eliminated, and more advanced moving image correction can be performed without deteriorating the image quality. It can be performed.

According to a second aspect of the present invention, in the first aspect of the invention, the peripheral pixels within the set range S are prioritized in advance, the count value comparing section outputs a comparison signal, and the motion vector detecting section outputs the comparison signal of the target pixel. When it is detected that there is no motion vector, the motion vector embedding unit embeds the motion vector of the pixel of interest with the motion vector of the pixel with a high ranking among the pixels having the motion vector in the setting range S. It is possible to easily specify a motion vector to be buried in the motion vector burying unit.

According to a third aspect of the present invention, in the first aspect of the present invention, when the count value comparing section outputs a comparison signal and the motion vector detecting section detects that there is no motion vector of the pixel of interest, a motion vector filling section is provided. Since the motion vector of the target pixel is filled with the average value of the motion vectors of the pixels having the motion vector within the setting range S by the unit, it is possible to easily specify the motion vector to be filled by the motion vector embedding unit. .

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, the pixels within the set range S are 9 pixels (3 × 3 pixels) of the target pixel and its surrounding eight pixels. The configuration of the motion vector delay unit can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a moving image correction circuit of a display device according to the present invention.

FIG. 2 is a block diagram illustrating a specific example of a motion vector delay unit in FIG. 1;

FIG. 3 shows pixels having a motion vector and pixels without a motion vector within a setting range S (3 × 3 pixels).
(B) shows a case where the number K of pixels having a motion vector is equal to or more than the set value Q (= 5) (when landfilling is performed), and FIG.

FIG. 4 is a diagram for explaining a subfield lighting method;
(A) is an explanatory diagram of a drive sequence in a 256-tone method, and (b) is a drive waveform diagram.

FIG. 5 is a block diagram showing a motion compensation circuit of a conventional display device.

FIG. 6 shows a pixel of interest e and peripheral pixels a, b, c, d, f,
FIG. 8 is an explanatory diagram showing a case where a motion vector to be detected for a target pixel e in a moving image portion including g, h, and i is not detected due to noise or fluctuation of a video signal (Me = 0).

[Explanation of symbols]

10, a motion vector detection unit, 12, 20, an input terminal,
14: moving image correction unit, 16: output terminal, 18: motion vector delay unit, 22: motion vector number counting unit, 24
... Count value comparison unit 26 ... Set value input terminal 28 ... Motion vector embedding unit a-d, f-i ... Peripheral pixels
e: target pixel, D: one-dot delay element, K: count value, LM: one-line delay element, Ma to Mi: motion vector, Mm: average value of motion vectors of pixels having a motion vector within the setting range S, PDP: Plasma display (an example of a display device), S: Target pixel e
And a set range including peripheral pixels a to d and f to i, SF1
ＳＦSFn: Subfield, Q: Setting value.

Claims (4)

[Claims] 1. A display apparatus which divides one frame into a plurality of subfields and emits a subfield corresponding to a luminance level of an input video signal to display a multi-tone image, based on the input video signal. A motion vector detection unit that detects a motion vector of a pixel in one or a plurality of frames, and a setting range S including a pixel of interest and peripheral pixels
A motion vector delay unit for obtaining a motion vector by the motion vector detection unit for each pixel in the set, and a motion vector number count for counting the number of pixels detected as having a motion vector among all the pixels in the set range S Unit, a count value comparison unit that compares whether the count value of the motion vector number counting unit is equal to or greater than a set value, and outputs a motion vector based on the outputs of the motion vector delay unit and the count value comparison unit. A motion vector embedding unit, and a moving image correcting unit that outputs a signal obtained by correcting the display position of each subfield of the pixel of interest based on the motion vector output from the motion vector embedding unit to the display device, In the motion vector embedding unit, there is no motion vector of the pixel of interest obtained by the motion vector delay unit, and the count value comparison unit outputs a comparison signal. In this case, the motion vector of the pixel having the motion vector within the set range S is output as the motion vector of the pixel of interest, and at other times, the motion vector of the pixel of interest obtained by the motion vector delay unit is output as it is. A moving image correction circuit for a display device, comprising: 2. The surrounding pixels within the set range S are prioritized, and the motion vector embedding unit outputs a comparison signal by the count value comparing unit, and the motion vector detecting unit detects that there is no motion vector of the target pixel. 2. The moving image correction circuit according to claim 1, wherein, when performing the above, a motion vector of a pixel with a high ranking among pixels having a motion vector within the set range S is output as a motion vector of the pixel of interest. 3. The motion vector embedding section, when the count value comparing section outputs a comparison signal and the motion vector detecting section detects that there is no motion vector of the pixel of interest, a motion vector having a motion vector within the set range S is provided. 2. The moving picture correction circuit according to claim 1, wherein an average value of a motion vector of the pixel is output as a motion vector of the pixel of interest. 4. The moving picture correction circuit for a display device according to claim 1, wherein the pixels within the set range S are 9 pixels (3 × 3 pixels) consisting of a target pixel and eight peripheral pixels.