JP3425611B2 - Liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used for terminals of video and information equipment, and more particularly,
The present invention relates to a technique for clearly displaying the movement of a cursor or the like.

[0002]

2. Description of the Related Art Generally, in a liquid crystal display device, the response speed for transitioning to a lighting state or a non-lighting state of liquid crystal is relatively slow, and when a cursor or the like moves at a high speed, the movement is extremely noticeable. It gets harder.

Therefore, for example, Japanese Patent Laid-Open No. 4-19786.
In the conventional liquid crystal display device disclosed in the publication,
A frame memory that stores image data for one frame period is provided, and input image data is extracted and stored for every n frames. During n frames, the same data is stored at a speed that matches the response speed of the liquid crystal display device. By repeatedly outputting and displaying, it is possible to prevent the movement of the cursor from being difficult to see.

[0004]

However, if the display data is displayed every n frames as in the prior art, the moving image is displayed discontinuously, so that the moving image is smooth. There was a problem that it disappeared and the display became unnatural.

In view of the above problems, the present invention provides a liquid crystal display device in which a moving image is continuously displayed without being unnatural and the movement of the cursor is not difficult to see. Is.

[0006]

Therefore, in the present invention, in order to solve the above-mentioned problems ,
The motion is emphasized by performing the filtering process in the time axis direction. You
That is, the input image data is delayed by one frame period.
A frame memory that allows the input image of the current frame
Data and the image data of the previous frame from the frame memory
Check the correlation with the data, and if there is no correlation,
It is a feature that the emphasis is placed on that part because it is the part .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal display device according to claim 1 of the present invention uses n bits of input image data as one frame.
The frame memory that delays by the period and the frame memory
Inverts the upper m bits of the output from the memory
Same inverting circuit and the same quantization bit of m-bit data as above.
A first multiplication circuit for multiplying the bell by k times (k> 1), and the inverting circuit
From the output from the first multiplication circuit
Motion enhancement processing means including an addition circuit of 1 and an input image
The remaining lower (n−m) bits of data and the previous
In the output of the frame memory, the lower (n-m) -bit
A second adder circuit for adding the
A second multiplication round that reduces the quantization level of the output of the path by half.
A smoothing means having a path and the outputs of both means.
And a means for adding,
For the lower (n−m) bits with a large noise component,
Since smoothing is performed, there is a difference in data between frames
If a key is detected, that part is emphasized, so
It has the effect of improving the visibility of the cursor and the like.

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, the gray scale of the input image data is changed.
Accordingly, the upper m bits to be processed by the motion enhancing means are
And the lower order (nm) to be processed by the smoothing means.
It is also characterized by changing the ratio of division with bits
Therefore, in an image where the gradation of input data changes
Can also have a stable effect.

Specific embodiments of the present invention will be described below. ( First Reference Example ) FIG. 1 is a block diagram of a liquid crystal display device according to a first reference example .

In FIG. 1, 1 is an image processing circuit as a contrast enhancement processing means for performing contrast enhancement on input image data, 3 is a motion detection circuit as a motion detection means for detecting a motion of the input image data, and 2 is a motion detection circuit. A control circuit as control means for controlling the contrast enhancement processing of the image processing circuit 1 based on the detection result of the motion detection circuit 3, 4
Is a liquid crystal display device.

The above-mentioned motion detection circuit 3 is provided with, for example, a frame memory, a subtraction circuit, etc., calculates a difference in image data between frames in pixel units, and obtains a motion amount based on the result.

When the amount of movement between frames detected by the movement detection circuit 3 exceeds a preset threshold value, the control circuit 2 judges that there is movement and emphasizes the contrast. Output a control signal.

The image processing circuit 1 is composed of, for example, a multiplication circuit for increasing the quantization level,
Of the input image data, the image data corresponding to the pixel position with motion is multiplied based on the control signal from the motion detection circuit 3 to increase the quantization level and the contrast enhancement processing is performed.

According to this structure, when the cursor or the like moves, the motion detection circuit 3 calculates the difference from the previous frame to obtain the motion amount, and the control circuit 2 presets the detected motion amount. When the threshold value is exceeded, a control signal for contrast enhancement is output to the image processing circuit 1. Therefore, the contrast of the moving cursor portion of the input image data is enhanced by the image processing circuit 1. As a result, the cursor portion has a higher contrast than the surrounding image. Therefore, the visibility of the cursor can be improved.

In the reference example 1, the control circuit 2
Although the contrast control is performed based on a predetermined threshold value, this threshold value does not necessarily have to be constant, and may be variable according to the content of the image data. Further, although the image processing apparatus 1 is supposed to enhance the contrast, it is also possible to perform processing such as contour enhancement.

Further, the image processing circuit 1 can also perform contrast enhancement only on one of the R, G, and B image data of the input image data. By doing so, the color of the moving portion changes, so that the visibility of the cursor and the like can be further improved. ( Second Reference Example ) FIG. 2 is a block diagram showing a second reference example of the present invention , in particular, a main part including a motion enhancement processing means.

In FIG. 2, reference numeral 30 is a motion enhancement processing means for performing a filtering process for detecting the presence or absence of motion in the time axis direction on the input image data to enhance the motion, and 35 is a liquid crystal display device.

The motion enhancement processing means 30 stores a frame of input image data for one frame and delays it for a period of one frame, and an inverting circuit 32 for inverting the output from the frame memory 31. A multiplication circuit 33 for multiplying the quantization level of the input image data by k (here, k = 2), and an addition circuit 34 for adding the output from the inverting circuit 32 and the output of the multiplication circuit 33 are provided.

The operation of the above configuration will be described with reference to the timing chart shown in FIG.

If the input image data in the current frame is, for example, as shown in FIG. 3 (a), in parallel with this, from the frame memory 31, for example,
Image data of one frame before as shown in FIG. 3B is read.

Here, when the cursor or the like is stationary for a period of one frame, there is no change in the image data before and after one frame as shown in the waveforms on the left side of FIGS. 3 (a) and 3 (b). However, if the cursor or the like moves during the period of one frame, as shown in the waveforms on the right side of FIGS. 3 (a) and 3 (b),
The image data before and after the frame has no correlation.

Since the inverting circuit 32 inverts the image data read from the frame memory 31, its output is as shown in FIG. 3 (c). Further, since the multiplication circuit 33 doubles the current input image data, the output at this time is as shown in FIG. 3 (d).

The adder circuit 34 outputs the output of the inverting circuit 32 and
Since the output of the multiplication circuit 33 is added, the output at this time is as shown in FIG. That is, when there is no movement before and after one frame, the quantization level of the image data does not change, but when there is movement before and after one frame,
The quantization level of the image data of that portion is doubled.

Then, the image data from the adding circuit 34 is output to the liquid crystal display device 35 and displayed.

As described above, in the second reference example , the motion enhancing processing means 30 performs the filtering process for detecting the presence or absence of the movement in the time axis direction on the input image data, and the moving portion has the signal amplitude of 2. Since the display is emphasized twice, the visibility of the cursor and the like is improved, and the liquid crystal display device 3
The slow response speed of 5 can be compensated.

Incidentally, thisReference exampleIn 2, the multiplication circuit 33
Doubles the quantization level of input image data (k = 2)
However, it is not limited to this.
Set the value of k appropriately considering the visibility of
And k> 1). (Form of implementationstate) aboveReference example2 constitutes the motion enhancement processing means 30.
The multiplication circuit 33 causes the input image data of the current frame
Since the quantization level of the data is simply doubled,
Therefore, noise components that have no correlation are emphasized as they are.
There is a risk of being lost. Form of this implementationThe state is, Such question
It is a solution to the problem.

[0027] Figure 4, the liquid crystal display device according to the shape condition of the present invention, in particular, is a block diagram showing a main part including a motion enhancement processing means and smoothing means.

In FIG. 4, reference numeral 50 is a motion enhancement process for enhancing the motion by performing a filtering process for detecting the presence or absence of motion in the time axis direction for the upper m bits (m <n) of the input image data consisting of n bits. Means, 58 is the rest of the lower order (n-m)
Smoothing means for smoothing bits, 56 is addition means for adding the outputs of both means 50 and 58, and 57 is a liquid crystal display device.

The motion enhancing processing means 50 has basically the same configuration as the motion enhancing processing means 30 in the case of the reference example 2 shown in FIG. 2, and the input image data consisting of n bits is equivalent to one frame period. A frame memory 51 for delaying only the above, an inverting circuit 53 for inverting the upper m-bit data of the output from the frame memory 51, and the same quantization level of the above-mentioned m-bit data k times (where k = 2) First to do
And a first adding circuit 56 for adding the output from the inverting circuit 53 and the output of the first multiplying circuit 55. The first adder circuit 56 is the same as the means 5 described above.
It is also used as an adding means for adding outputs of 0 and 58.

On the other hand, the smoothing means 58 stores the remaining lower (n−m) bits of the input image data and the lower (n−m) bits of the output of the frame memory 51. And a second multiplication circuit 54 for reducing the quantization level of the output of the second addition circuit 52 to ½.

Next, the operation of the above configuration will be described with reference to the timing chart shown in FIG. It should be noted that here, the input image data is data having a bit width of 8 bits (n = 8), and the image data to be processed by the motion enhancement processing means 50 has upper 4 bits (m = 4). ,
It is assumed that the image data to be processed by the smoothing means 58 is the remaining lower 4 bits (n−m = 4).

If the input image data in the current frame is, for example, as shown in FIG. 5 (a), the first multiplication circuit 55 extracts the upper 4 bits of this input image data and outputs the lower bits. The quantization level is doubled by supplementing "0" to 4 bits. Therefore, the output of the first multiplication circuit 55 becomes as shown in FIG. 5 (b). That is, in the output of 8 bits, the data of the lower 4 bits containing a lot of noise components is “0”, and the level of the upper 4 bits is emphasized.

In parallel with the above operation, the frame memory 5
The image data of one frame before is read from 1, and this is added to the inversion circuit 53. The inverting circuit 53 takes out the upper 4 bits from the output from the frame memory 51,
The remaining lower 4 bits are complemented with "0" and inverted. As a result, the output of the inverting circuit 53 becomes as shown in FIG.

The second adder circuit 52 adds the lower 4 bits of the current input image data and the lower 4 bits of the image data of one frame before read from the frame memory 51. Then, the second multiplication circuit 54 at the next stage
Reduces the quantization level of the addition output to 1/2. As a result, the output of the second multiplication circuit 54 becomes as shown in FIG. 5 (d). That is, since the noise component has no correlation before and after one frame, it is averaged (smoothed) by adding the data before and after one frame and halving it.

The first adding circuit 56 is the first multiplying circuit 5
5, the output of the inverting circuit 53, and the second multiplication circuit 5
Since the outputs of 4 are added together, the output at this time is as shown in FIG.
It becomes as shown in (e). That is, when there is no movement around one frame (in the case of the waveform on the left half of FIG. 5), there is almost no difference between the input image data and the output image data from the first addition circuit 56 except for the noise component. However, when there is motion around one frame (in the case of the waveform in the right half of FIG. 5), the quantization level of the upper 4 bits of the image data is doubled and emphasized. To be done. Further, for the lower 4-bit image data containing a lot of noise components, the average of the previous frame and the current frame is taken, so that the noise components are effectively suppressed regardless of the presence or absence of image motion.

The image data from the first adding circuit 56 is output to the liquid crystal display device 57 and displayed.

[0037] Thus, in the form status of this embodiment, since the motion of some portion of the input image data by the motion enhancement processing means 50 is stressed, can only compensate for the slow response speed of the liquid crystal display device Instead, the smoothing means 58 averages the noise components.

It should be noted, Oite to form state of this embodiment. The image data is divided into the upper 4 bits (m = 4) and the lower 4 bits (n−m = 4), but the processing is not limited to this, and the processing is performed according to the gradation of the input image data. For example, the division ratio may be changed such as upper 6 bits (m = 6) and lower 2 bits (n−m = 2). Further, the upper and lower divisions may be changed according to the bit width of the image data.

Further, the shape condition of the present invention, the first multiplier circuit 55 is twice the quantization level of the input image data (k =
However, the present invention is not limited to this, and the value of k can be set appropriately (k> 1) in consideration of the visibility of the cursor and the like.

[0040]

According to the present invention, in a liquid crystal display device equipped with a liquid crystal display device having a slow response speed, a moving image is continuously displayed without being unnatural and the movement of the cursor becomes difficult to see. Therefore, the visibility can be improved more than ever before.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a liquid crystal display device according to a first reference example of the present invention.

FIG. 2 is a block diagram showing a main part of a liquid crystal display device according to a second reference example of the present invention.

FIG. 3 is a timing chart for explaining the operation of the liquid crystal display device according to the second reference example of the present invention.

Block diagram showing the main part of a liquid crystal display device definitive the form status of implementation of the invention; FIG

Figure 5 is a timing chart for explaining the operation of the liquid crystal display device definitive to form state of the present invention

[Explanation of symbols]

1 Image processing circuit 2 control circuit 3 Motion detection circuit 4,35,57 Liquid crystal display device 30 motion enhancement processing means 31,51 frame memory 32 multiplication circuit 33,53 Inversion circuit 34 Adder circuit 50 motion enhancement processing means 52 Second adder circuit 54 Second Multiplier Circuit 55 First Multiplier Circuit 56 First Adder Circuit 58 smoothing means

Continuation of the front page (56) Reference JP 5-11971 (JP, A) JP 3-189693 (JP, A) JP 3-51888 (JP, A) JP 2-153687 (JP , A) JP-A-6-324802 (JP, A) JP-A-6-46358 (JP, A) JP-A-2-153688 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G09G 3/00-3/38 G02F 1/133 505-580 H04N 5/66-5/74

Claims (2)

(57) [Claims] 1.One frame of input image data consisting of n bits
Frame memory that delays the frame period, and the frame
The upper m bits of the output from the memory
Inverting circuit that inverts the same quantum of m-bit data
A first multiplication circuit for multiplying the conversion level by k times (k> 1), and the inversion
Add the output from the circuit and the output of the first multiplication circuit
Motion enhancement processing means including a first addition circuit, The remaining (n−m) bits of data in the lower part of the input image data
And the lower (n-m) bit of the output of the frame memory.
And a second adder circuit for adding
Second to reduce the quantization level of the output of the adder circuit of
Smoothing means including a multiplication circuit of Adding means for adding the outputs of both means, A liquid crystal display device comprising: 2. The liquid crystal display device according to claim 1 , wherein the processing by the motion enhancing means is performed according to the gradation of the input image data.
Target high-order m bits and processing target by smoothing means
The ratio of division with the lower (nm) bits becomes
A liquid crystal display device characterized by: