JPH10233942A - Image display controller and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration of an image in the case of executing interpolation filter processing. SOLUTION: A video camera 1 is incorporated with a gamma correction circuit 2 and applies gamma correction processing to outputted image data. Image data outputted from the video camera 1 are given to an inverse gamma correction circuit 4, where the inverse gamma correction processing is made to obtain image data with a linear characteristic. Interpolation filter processing such as magnification, reduction and pixel number conversion processing is applied to the image data by an interpolation filter 5, and an LCD characteristic correction circuit 6 conducts correction processing reverse to the nonlinear characteristic in an LCD 7. Image data subject to correction processing by the LCD characteristic correction circuit 6 are outputted to the LCD 7, on which the data are displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display control apparatus and method, and more particularly, to an image display control apparatus and method capable of accurately displaying an interpolated image.

[0002]

2. Description of the Related Art FIG. 10 shows a configuration example of a conventional image display control device. The video camera 81 captures an image of a subject, and applies gamma correction circuit 8 to the image data of the subject.
After performing gamma correction in step 2, the A / D conversion circuit 83
The data is D-converted and output to the interpolation filter 84. The interpolation filter 84 executes an interpolation filter process such as a process of enlarging and reducing an image and a process of converting a sampling frequency (the number of pixels). The image data output from the interpolation filter 84 is input to a CRT 85 and its D / A conversion circuit 8
6, after D / A conversion, smoothed by LPF87, CR
Displayed at T85.

The CRT 85 has a non-linear characteristic with respect to the input.
2, the image data is corrected in advance so that the non-linear characteristic is canceled out, so that the image is linearly displayed on the CRT 85.

Next, the interpolation filter processing in the interpolation filter 84 will be described.

[0005] Enlargement or reduction of an image and conversion of the sampling frequency (the number of pixels) of the image (conversion to an image of a standard having a different resolution) both exist from each pixel of the original image to the original image. This is realized by performing an operation for obtaining data of a missing pixel. Therefore, both of the above two processes can be performed by using the interpolation filter.

FIG. 11 shows an example of a part of an original image. The circles in the figure represent the positions of the pixels. This portion includes eight pixels in the horizontal direction and six pixels in the vertical direction.

Next, processing for enlarging the original image by, for example, (10/7) will be described. Note that the magnification is expressed not by the area but by the length ratio. When the image of FIG. 11 is enlarged, the display image standard is not changed. That is, the arrangement of the pixels (pixel interval and the like) is kept the same as in FIG. When the enlargement process is performed in this manner, the resulting image is as shown in FIG. In this case, since the magnification is 1.429 (= 10/7), the vertical and horizontal lengths of the image are each multiplied by 1.429, and the number of pixels (display area) is about 1.42.
To increase to 9 ^twice.

For example, the number of pixels in the horizontal direction (horizontal scanning direction) is eight in the original image, but is one after enlargement.
The number is 1 or 12 (8 × 10/7 = an integer close to 11.429). Therefore, since the positional relationship of each pixel corresponding to the same part of the image in the similar image after enlargement is different from the positional relationship in the original image, the value of the data (expressing luminance and color) of each pixel after enlargement is Will be different from that of the original image.

FIG. 13 shows a positional relationship between horizontal pixels in an original image and an enlarged image when the image is enlarged at a magnification of (10/7).

In the figure, the upper Ri (i = 1, 2,...)
Represents the position of the pixel data of the original image, and the lower Q
i (i = 1, 2,...) represents the position of the interpolated pixel data after the enlargement. The pixels corresponding to Ri are arranged at an interval (10/7) times the interval between the pixels corresponding to Qi. Note that FIG. 13 shows only the state of enlargement in the horizontal direction, but the same applies to the vertical direction, and a description thereof will be omitted.

The value of the data of each pixel (interpolated pixel) after enlargement depends on the correspondence relationship with the position of each pixel of the original image as shown in FIG. It is calculated from the value by performing an interpolation filter operation, that is, a convolution operation of an interpolation function.

Next, a process for increasing the sampling frequency by, for example, (10/7) without changing the size (display area) of the image will be described. This sampling frequency conversion is equivalent to converting the resolution to a (10/7) times higher image standard. That is, the number of pixels in the horizontal direction is (10/7)
Changed to double. In this case, the original image of FIG.
As shown in, the one-dimensional to about 1.429 times the number of pixels of the image, the two-dimensionally image the number of pixels having an areal density of 1.429 ^doubled, are converted, respectively.

The correspondence between each pixel in FIG. 11 and each pixel in FIG. 12 and the correspondence between each pixel in FIG. 11 and each pixel in FIG. 14 are as shown in FIG. Therefore, the operation for converting to an image standard having a large number of pixels is performed in the same manner as the above-described operation for enlarging an image.

Next, the original image of FIG.
3) The process of reducing the size to twice will be described.

When the image is reduced, the standard of the image is not changed, so that the arrangement of pixels in the reduced image, that is, the pixel interval, is the same as that of the original image shown in FIG.

FIG. 15 shows the original image of FIG.
3) shows an image reduced by a factor of two. In this case, the magnification is 0.769 (= 10/13).
The length of the sides is reduced to 0.769 times the number of pixels constituting the reduced image is reduced to approximately 0.769 ^2.

For example, in the original image, the number of pixels in the horizontal direction is 8, but in the reduced image, the number of pixels in the horizontal direction is an integer close to 6 or 7 (8 × 10/13 = 6.154). )become. Accordingly, since the positional relationship of each pixel corresponding to the same part of the image in the reduced similar image is different from the positional relationship of each pixel in the original image, the data value of each pixel after reduction (expressing luminance and color) Is different from that of the original image.

FIG. 16 shows the positional relationship between pixels in the horizontal direction between the original image and the reduced image when the image is reduced by a factor of (10/13).

In the figure, the upper Ri (i = 1, 2,...)
Represents the position of the pixel data of the original image, and the lower Q
i (i = 1, 2,...) represents the position of the data of the interpolated pixel after reduction. The pixels corresponding to Ri are arranged at an interval (10/13) times the interval between the pixels corresponding to Qi. FIG. 16 shows only the state of reduction in the horizontal direction, but the same applies to the vertical direction.
The description is omitted.

The data value of each pixel after reduction is calculated by interpolation filter calculation from the pixel data values of several surrounding original images in accordance with the correspondence relationship with each pixel of the original image as shown in FIG. That is, it is calculated by performing a convolution operation of the interpolation function.

Next, processing for increasing the sampling frequency by, for example, (10/13) without changing the size of the image will be considered. This sampling frequency conversion makes the resolution (10/13)
It is equivalent to converting to a double lower image standard. That is, the number of pixels is one-dimensionally changed to (10/13) times. In this case, as shown in FIG. 17, the original image of FIG.
The dimensionally on the image of the number of pixels having an areal density of 0.769 ^doubled, it is converted, respectively.

The correspondence between each pixel in FIG. 11 and each pixel in FIG. 15 and the correspondence between each pixel in FIG. 11 and each pixel in FIG. 17 are as shown in FIG. 16 and are the same. Therefore, the calculation operation for converting to a low-resolution image standard is performed in the same manner as the above-described calculation operation for image reduction.

As described above, the image is enlarged or reduced,
Alternatively, when converting the sampling frequency (the number of pixels), interpolation filter processing for calculating pixel data at a position that did not exist in the original image is required.

Next, the operation of the interpolation filter will be described.

As shown in FIG. 18, the sampling interval of the original image is represented by S, and the position separated by a distance (phase) P from the position of the pixel R of the original image is determined by the position of the pixel Qi generated by interpolation (interpolation point). ), The value of the pixel Qi is calculated by a convolution operation on the pixel value R of the surrounding original image.

According to the “sampling theorem”, when ideal “interpolation” is performed, the sinc function as shown in equation (1) and FIG. The convolution operation from the pixel of to the pixel in the future for infinite time is performed. f (x) = sinc (π × x) = sin (π × x) / (π × x) (1) Here, π represents a pi.

However, in practice, it is necessary to calculate an interpolated value within a finite time. Therefore, an interpolating function that approximates a sinc function within a finite range is used.

As the approximation method, a nearest neighbor approximation, a bilinear approximation, a Cubic approximation, and the like are known.

In the nearest neighbor approximation method, data of one pixel after interpolation is calculated from data of one pixel of the original image by using an interpolation function as shown in equation (2) and FIG. 19B. . Note that the variable x in Equation (2) and FIG.
It is assumed that the displacement in the horizontal direction from the pixel position of the original image represents an amount normalized by the sample interval of the original image. f (x) = 1−0.5 <x ≦ 0.5 f (x) = 0−0.5 ≧ x, x> 0.5 (2)

In the bilinear approximation method, data of one pixel after interpolation is calculated from data of two pixels of an original image by using an interpolation function as shown in equation (3) and FIG. 19C. . Note that the variable x in Equation (3) and FIG.
It is assumed that the displacement in the horizontal direction from the pixel position of the original image represents an amount normalized by the sample interval of the original image. The bilinear approximation method is well known as linear interpolation, and a weighted average is calculated. f (x) = 1− | x || x | ≦ 1 f (x) = 0 | x |> 1 (3)

In the Cubic approximation method, data of one pixel after interpolation is calculated from data of four pixels of an original image by using an interpolation function as shown in equation (4) and FIG. 19D. The variable x in equation (4) and FIG.
Represents the amount of displacement in the horizontal direction from the pixel position of the original image normalized by the sample interval of the original image. f (x) = | x | 3 -2 | x | 2 +1 | x | ≦ 1 f (x) = - | x | 3 +5 | x | 2 -8 | x | +4 1 <| x | ≦ 2 f (X) = 0 2 <| x | (4)

These convolution operations can be performed using a so-called FIR digital filter. In this case, the center of the interpolation function is set to the interpolation point, and a value obtained by sampling the interpolation function at the sampling points of the original image nearby by a predetermined number of pixels is used as an interpolation filter coefficient set.

For example, in the case of performing the interpolation operation by the bilinear approximation method, when the phase P is 0.0, the two weights (filter coefficients) constituting the filter coefficient set are 1.0 and 0.0. , A coefficient set that directly outputs the pixel data value of the original image at the same position.

When the phase P is 0.5, the two filter coefficients are 0.5 and 0.5, and when P is 0.3, they are 0.7 and 0.3.

When the interpolation operation is performed by the Cubic approximation method, when the phase P is 0.0, the four weights (filter coefficients) constituting the filter coefficient set are 0.0, 1.
The coefficient set is 0, 0.0, and 0.0, and is a coefficient set that directly outputs the data value of the original image pixel at the same position.

When the phase P is 0.5, the four filter coefficients are -0.125, 0.625, 0.62
5, and -0.125, and when P is 0.3, -0.063, 0.847, 0.36
3, and -0.147.

At this time, since the phase P with the pixel of the original image is different for each interpolation point for calculating data,
A plurality of sets of filter coefficients corresponding to different phases are required.

By the way, in the image display control device shown in FIG. 10, it is assumed that the video camera 81 outputs a video signal (luminance signal) shown in FIG. This video signal is gamma-corrected by a gamma correction circuit 82.
As shown in FIG. 21, the gamma correction curve largely reflects the change in a relatively low luminance portion (a portion having a small amplitude), and in a relatively high luminance portion (a portion having a large amplitude). The video signal shown in FIG. 20A has the characteristic that the change is reflected to a small extent.
The video signal has a slightly distorted characteristic as shown in FIG.

The interpolation filter 84 performs an interpolation filter process on the gamma-corrected video signal. That is, FIG.
As shown in FIG. 20C, a video signal having the same characteristics as those shown in FIG. 20B is sampled, and new pixel data is generated by interpolation filter processing.

The pixel data is D / A-converted by a D / A conversion circuit 86 of the CRT 85, and then the LPF 87
And displayed on the CRT 85. This CRT85
Since the input / output characteristics are inverse to the gamma correction curve, the CRT 85 can eventually display a correct image.

On the other hand, as shown in FIG. 22, for example, the video signal output from the video camera
When the D / A conversion circuit 92 performs D / A conversion, smoothes the data with the LPF 93, and displays it on the LCD 91, the linear characteristics of the entire system are not maintained.
That is, since the gamma correction by the gamma correction circuit 82 corrects nonlinearity when the display is a CRT, the output of the video camera 81 is output to the LCD.
When displayed at 91, the linearity is no longer maintained.

However, even when the linearity is not maintained, as shown in FIG.
When the PF 93 is provided, a signal close to the original signal can be restored and displayed.

[0043]

However, for example, as shown in FIG. 23, the LCD is connected to the LPF shown in FIG.
In a case where the LCD 93A is omitted, and the staircase-shaped voltage output from the D / A conversion circuit 92 is supplied to each pixel as it is, the LCD 91A has a simple configuration. It becomes difficult to recover a close signal.

That is, as shown in FIG. 24, when the sampling points indicated by x in the figure correspond to the peaks of the original signal, the original signal (peak point) is restored even when the LPF 93 does not exist. For example, FIG.
As shown in FIG. 5, when the peak point of the original signal does not coincide with the sampling point, it is difficult to reproduce the peak point unless the LPF 93 is provided. Because the linearity is not secured at this time, even if the values of the sampling points before and after the peak of the original signal are added, the total luminance value does not correspond to the luminance value (peak value) of the original signal. It is because it becomes.

This will be described with reference to an impulse signal as shown in FIGS. 26 and 27. That is, FIG.
As shown in FIG. 6, when sampling is performed at the peak value of the impulse, the peak value can be reproduced by displaying the value of the sampling point even if the LPF 93 is not provided. But FIG.
As shown in FIG. 7, when the sampling point does not coincide with the peak value, the level of the sampling point is non-linear with the original signal, so that the sum of the luminance becomes a value that does not correspond to the peak value. Would. Therefore, the displayed image becomes an image degraded from the original image.

The present invention has been made in view of such a situation, and suppresses image deterioration.

[0047]

According to a first aspect of the present invention, there is provided an image display control device, comprising: a reverse gamma correction unit for performing reverse gamma correction on an output of a video camera; a processing unit for performing an interpolation filter process on an output of the video camera; And a display characteristic correcting means for correcting the non-linear characteristic.

According to a third aspect of the present invention, there is provided an image display control method, comprising: an inverse gamma correction step for performing an inverse gamma correction on an output of a video camera; a processing step for performing an interpolation filter process on an output of the video camera; And a display characteristic correcting step.

According to a fourth aspect of the present invention, there is provided an image display control device, comprising: a processing unit for performing an interpolation filter process on an output of a computer;
Display characteristic correction means for correcting the non-linear characteristic of the display corresponding to the connected display.

An image display control method according to a seventh aspect includes a processing step of performing an interpolation filter process on an output of a computer, and a display characteristic correction step of correcting a non-linear characteristic of a display corresponding to a connected display. It is characterized by the following.

An image display control device according to claim 8 is a processing means for performing interpolation filter processing on the data of the mixed image, and determining whether the mixed image is an image from a video camera or an image from a computer. It is characterized by comprising a determining means for determining and a display characteristic correcting means for correcting the non-linear characteristic of the display in accordance with the result of the determination by the determining means.

The image display control method according to claim 11 is
A processing step of performing an interpolation filter process on the data of the mixed image, and whether the mixed image is an image from a video camera,
Alternatively, the image processing apparatus further includes a determining step of determining whether the image is an image from a computer, and a display characteristic correcting step of correcting a non-linear characteristic of the display in accordance with the determination result of the determining step.

In the image display control device according to the first aspect and the image display control method according to the third aspect, the output of the video camera is subjected to inverse gamma correction and the nonlinear characteristic of the display is corrected.

In the image display control device according to the fourth aspect and the image display control method according to the seventh aspect, the nonlinear characteristic of the display is corrected corresponding to the connected display.

In the image display control device according to the eighth aspect and the image display control method according to the eleventh aspect, it is determined whether the mixed image is an image from a video camera or an image from a computer. The nonlinear characteristic of the display is corrected according to the determination result.

[0056]

FIG. 1 is a block diagram showing a configuration example of an image display control device according to the present invention. Video camera 1
Is configured to take an image of a subject (not shown), subject the image signal to gamma correction by a gamma correction circuit 2, A / D conversion by an A / D conversion circuit 3, and output. The gamma correction by the gamma correction circuit 2 is for correcting a CRT as a display for displaying an image, which has a nonlinear input / output characteristic. The gamma correction circuit 2 is built in an ordinary video camera.

The inverse gamma correction circuit 4 performs an inverse gamma correction process on the image data output from the video camera 1. As in the case of the interpolation filter 84 in FIG. 10, the interpolation filter 5 performs image enlargement and reduction processing,
The conversion processing of the sampling frequency (the number of pixels) of the image is executed.
The LCD (Liquid Crystal Display) characteristic correction circuit 6
Processing for correcting the non-linear input / output characteristics of the CD 7 to linear input / output characteristics is performed. The LCD 7 has a built-in D / A conversion circuit 8 and an LPF (low-pass filter) 9. The D / A conversion circuit 8 D / A converts the image data supplied from the LCD characteristic correction circuit 6 and smoothes the image data with the LPF 9. To be displayed.

The inverse gamma correction circuit 4 includes a gamma correction circuit 2
The LCD characteristic correction circuit 6 is a circuit that performs a process of correcting the input / output characteristics of the LCD 7 and the inverse characteristics thereof, and is implemented by, for example, a memory mapping method. Can be.

Next, the operation will be described. The video camera 1 captures an image of a subject (not shown), and performs gamma correction on the image signal using a gamma correction circuit 2. Then, the gamma-corrected image signal is A / D converted by the A / D conversion circuit 3 and output as digital image data. The inverse gamma correction circuit 4 performs inverse gamma correction on the image data. As a result, the image data output by the inverse gamma correction circuit 4 has linear characteristics. Therefore, when this image data is subjected to the interpolation filter processing by the interpolation filter 5, the resulting interpolated image data becomes image data exactly corresponding to the original image, and its degradation can be suppressed.

The image data output from the interpolation filter 5 is input to an LCD characteristic correction circuit 6 where a process for correcting the non-linear characteristics of the LCD 7 is performed. And LC
The image data output from the D characteristic correction circuit 6 is
7 after D / A conversion by the D / A conversion circuit 8 of LP
The image is smoothed by F9 and displayed on the LCD 7. LCD7 is
Since the image data input from the LCD characteristic correction circuit 6 is displayed on the LCD 7 as a result, it has a linear characteristic because the LCD characteristic correction circuit 6 has a non-linear characteristic opposite to the correction characteristic. In this manner, the LCD 7 displays an image that accurately reproduces the image captured by the video camera 1.

In the embodiment shown in FIG. 1, the LCD 7 is provided with the LPF 9, but in this system, as described above, the linearity is ensured. LCD7 omitting LPF9
A can be used. That is, in the case of this embodiment, since the LCD 7A has a simple configuration,
The staircase voltage output from the / A conversion circuit 8 is L
The data is directly supplied to each pixel of the CD 7A. Even in this case, since the linearity of the entire system is ensured, an image that is not so different from the original image in practical use can be restored and displayed.

FIG. 3 shows another example of the configuration of the image display control device of the present invention. In this configuration example, a computer (including a word processor) 11 creates a text image (image for displaying characters) or a computer graphics image, and supplies the image data to the interpolation filter 5. The image data subjected to the interpolation filter processing by the interpolation filter 5 is supplied to the gamma correction circuit 12 and the LCD.
It is supplied to a characteristic correction circuit 6. Gamma correction circuit 12
Performs a gamma correction process on the image data supplied from the interpolation filter 5, similarly to the gamma correction circuit 2 in FIG.

When the display connected to the subsequent stage is the CRT 14 as shown in FIG. 3, the switch 13 is switched to the upper side in the figure, and as shown in FIG.
If it is D7, it is switched to the lower side in the figure. FIG.
In the embodiment, since the CRT 14 including the D / A conversion circuit 15 and the LPF 16 is connected to the switch 13, the switch 13 is switched to the upper side in the drawing, and the image data output from the gamma correction circuit 12 is switched. Is a CRT
14.

On the other hand, when the LCD 13 is connected to the switch 13 as a display as shown in FIG. 4, the switch 13 is switched to the lower side in the figure, If the image data to be output is L
It is supplied to CD7.

The LCD characteristic correction circuit 6 and the gamma correction circuit 12 are composed of the same circuit using a memory mapping method, and their correction characteristics are made variable in accordance with the type of display connected at the subsequent stage. It can also be configured.

The image data created by the computer 11 is input to the interpolation filter 5 and is subjected to interpolation filter processing. When the switch 13 is connected to the CRT 14 as shown in FIG. 3, after the interpolation image data output from the interpolation filter 5 is gamma-corrected by the gamma correction circuit 12, the switch 13 is turned off. Via CRT1
4 is input. This data is subjected to D / A conversion by the D / A conversion circuit 15 and then smoothed by the LPF 16 to obtain the CRT 1
4 is displayed.

Unlike the video camera 1 shown in FIG. 1, the computer 11 does not assume that the display for displaying the image data to be created is a CRT.
Image data is created and output on the assumption that an image is displayed on a display having no linear gamma correction circuit and linear input / output characteristics. Therefore, the interpolation pixel data obtained as a result of the interpolation filter processing by the interpolation filter 5 is
It has a linear characteristic. However,
Since the CRT 14 has nonlinear input / output characteristics, the image data output from the interpolation filter 5 is directly
When it is supplied to T14 and displayed, it is not possible to secure linear characteristics of the whole system. Therefore, the image data output from the interpolation filter 5 is gamma-corrected by the gamma correction circuit 12, and then output to the CRT 14, so that the linear characteristics of the entire system are ensured.

As shown in FIG.
When the LCD 7 is connected, the image data output from the interpolation filter 5 is output to the LCD 7 after the LCD characteristic correction circuit 6 performs a correction process of the reverse characteristic of the LCD 7.
As a result, also in this case, the linear characteristics of the entire system can be secured.

The text image and computer graphics image data created by the computer 11 are
Many have a steeply changing portion that does not satisfy the conditions of the sampling theorem. In addition, since the LCD supplies a predetermined voltage value to each pixel, the LCD has a simple configuration, and supplies the voltage on the staircase waveform output from the D / A conversion circuit 8 to each pixel as it is. It is conceivable to do so. That is, the LPF 9 may be omitted. If the LCD has a configuration in which the LPF 9 is omitted and the image data does not satisfy the sampling theorem, it is difficult to accurately reproduce the original image.

Therefore, as shown in FIG.
Is connected to the LCD 7A having no LPF 9, the image data output from the computer 11 is
After the high-frequency component is band-limited by the PF 31, the high-frequency component can be supplied to the interpolation filter 5. By doing so, the image data output from the computer 11 can be converted into data that satisfies the Nyquist theorem. As a result, it is possible to suppress the deterioration of the image displayed on the LCD 7A.

The LPF 31 may be configured to pass only low-frequency components with a digital filter, or may be configured to generate and add intermediate data to a steep image data portion. .

FIG. 6 shows still another configuration example.
In this configuration example, the image data output from the video camera 1 and the image data output from the computer 11 are
The mixing is performed in the mixing circuit 41.
Then, the mixed image data output from the mixing circuit 41 is output to the contact CRT of the switch 43 and the inverse gamma correction circuit 4.
2, and the contact C of the switch 44, respectively.

The inverse gamma correction circuit 42 is a circuit corresponding to the inverse gamma correction circuit 4 in FIG. 1 and performs inverse gamma processing on the input image data and outputs the image data to the contact LCD of the switch 43. It has been done. Switch 43
Selects the image data of either the contact CRT or the contact LCD and supplies it to the contact V of the switch 44. The switch 44 selects one of the image data of the contact V and the contact C and supplies the selected image data to the interpolation filter 45. The interpolation filter 45 performs the same processing as the interpolation filter 5 in FIG.

The output of the interpolation filter 45 is
, A LCD characteristic correction circuit 46, a gamma correction circuit 48, and an LCD characteristic correction circuit 49. The LCD characteristic correction circuit 46 is a circuit corresponding to the LCD characteristic correction circuit 6 in FIG. 1, and performs correction processing of the non-linear characteristic and the reverse characteristic of the LCD on the input image data, and the contact LCD of the switch 47. Output. The gamma correction circuit 48 is a circuit corresponding to the gamma correction circuit 12 in FIG. 3, performs gamma correction on input image data, and supplies the image data to the contact CRT of the switch 50. Similar to the LCD characteristic correction circuit 46, the LCD characteristic correction circuit 49 performs a process of correcting the non-linear characteristic of the input image data and the reverse characteristic of the input image data, and then supplies the image data to the contact LCD of the switch 50. .

The switch 47 is provided with a contact CRT or a contact L
One of the image data supplied to the CD is selected and supplied to the contact V of the switch 51. The switch 50 selects one of the image data supplied to the contact CRT and the contact LCD, and supplies the selected data to the contact C of the switch 51. The switch 51 selects one of the image data supplied to the contact point V and the contact point C and outputs it to the LCD 7 (FIG. 7) or the CRT 14 (FIG. 6) as a subsequent display.

The switch 43, the switch 47 and the switch 50 are connected to the switch 51 as shown in FIG.
14 is connected, the upper contact CRT in FIG.
, And when the LCD 7 is connected to the switch 51 as shown in FIG. 7, the switch is switched to the contact LCD side.

The determination circuit 52 determines whether the image data supplied from the mixing circuit 41 is image data (gamma corrected image data) output from the video camera 1 or image data output from the computer 11 (gamma corrected image data). Is determined, and a coefficient k corresponding to the determination result is output to the switch 44 and the switch 51. The switch 44 and the switch 51 determine the coefficient k
Performs a switching operation.

That is, the switch 44 and the switch 51
Is configured as shown in FIG. The multiplier 61
The image data supplied from the contact point V is multiplied by a coefficient k and output to the adder 65. In the register 64,
The value 1.0 is held, and the subtractor 63
4 is subtracted from the coefficient k supplied from the determination circuit 52 from the output (1.0) of
Output to The multiplier 62 multiplies the image data supplied from the contact point C by a coefficient (1−k) and outputs the result to the adder 65. The adder 65 adds the output of the multiplier 61 and the output of the multiplier 62 and outputs the result to a circuit at a subsequent stage.

The output of the LCD characteristic correction circuit 46 is
By supplying the data to the contact LCD of the switch 50, the LCD characteristic correction circuit 49 can be omitted.

Next, the operation will be described. The mixing circuit 41 mixes the image data output from the video camera 1 and the image data output from the computer 11, and outputs, for example, image data as shown in FIG. In FIG. 9, for convenience of description, digital image data output from the mixing circuit 41 is shown in analog form. In FIG. 9, the image data in the period T is the image data generated by the computer 11, and the image data in the other periods is the image data output from the video camera 1. Since the image data in the period T is image data generated by the computer 11, its level changes sharply. On the other hand, since the band of the image data output from the video camera 1 is limited in accordance with the standard, a steep change of data exceeding a certain level cannot occur.

The determination circuit 52 calculates the difference between successive pixel data, compares the difference value with a predetermined reference value, and accumulates in the memory the position where a data string having a difference value larger than the reference value exists. Then, image data during a period in which such pixel data is locally concentrated is determined as image data generated by the computer 11.

When the image data generated by the computer 11 is detected, the determination circuit 52 sets the coefficient k to 0, and when the image data of the computer 11 is not detected (when the image data output from the video camera 1 is detected), Coefficient k
Is set to 1. As a result, switch 44 and switch 5
In 1, when the coefficient k is set to 0 (when image data of the computer 11 is detected), the multiplier 62
Is the image data supplied from the contact C (computer 1
(The image data output by 1) is supplied to the adder 65 as it is. On the other hand, the multiplier 61 sets the image data supplied from the contact point V to substantially zero. As a result, the adder 65 outputs the image data input from the contact C.

On the other hand, when the coefficient k is set to 1, the multiplier 61 supplies the image data input from the contact point V (the image data output from the video camera 1) to the adder 65 as it is. . On the other hand, the multiplier 62
The image data supplied from the contact point C is substantially 0 (= 1−1).
k). Therefore, the adder 65 outputs the image data supplied from the contact point V.

Here, the coefficient k is set to 1 to 0 or 0 to 1
If the image is switched instantaneously, a discontinuous portion occurs in the image. To prevent this, the value of the coefficient k is gradually increased to 0.
From 1 to 1 or from 1 to 0 over a period of time. This prevents a discontinuous portion from being generated in the image data switching unit.

The determination process in the determination circuit 52 is as follows.
Since the image is not formed one-dimensionally but two-dimensionally, it is preferable to detect it two-dimensionally.

As shown in FIG. 6, the switch 51
14 is connected, switch 43 and switch 4
7 is switched to the contact CRT side. Therefore, when the image data output from the video camera 1 is output from the mixing circuit 41, the image data is supplied to the interpolation filter 45 via the contact CRT of the switch 43 and the contact V of the switch 44. The data subjected to the interpolation filter processing by the interpolation filter 45 is supplied to the CRT 14 via the contact CRT of the switch 47 and the contact V of the switch 51. This image data is converted by the D / A converter 15 into D
/ A conversion, smoothed by LPF16, CRT
14 is displayed.

On the other hand, when the mixing circuit 41 is outputting image data generated by the computer 11, this image data is input to the interpolation filter 45 via the contact C of the switch 44 and is subjected to interpolation filter processing. . Then, the image data that has been subjected to the interpolation filter processing is output to the gamma correction circuit 48.
Is output to the CRT 14 via the contact CRT of the switch 50 and the contact C of the switch 51.
Is displayed.

Further, as shown in FIG. 7, when the LCD 7 is connected to the switch 51, the switches 43, 47 and 50 are switched to the contact LCD side. In this case, when image data output from the video camera 1 is output from the mixing circuit 41, the image data is subjected to inverse gamma correction by the inverse gamma correction circuit 42, and then the contact LCD of the switch 43 and the contact of the switch 44. V, input to the interpolation filter 45,
Interpolation filter processing is performed. The image data output from the interpolation filter 45 is output to the LCD 7 via the contact LCD of the switch 47 and the contact V of the switch 51 after being subjected to correction processing in the LCD characteristic correction circuit 46. In the LCD 7, this image data is converted by the D / A conversion circuit 8 into a D / A
After the conversion, the data is smoothed by the LPF 9 and displayed on the LCD 7.

When the image data generated by the computer 11 is output from the mixing circuit 41, the image data is supplied to the interpolation filter 45 via the contact C of the switch 44.
And subjected to interpolation filtering. Interpolation filter 4
The image data output from the LCD 5 is corrected by the LCD characteristic correction circuit 49, and then output to the LCD 7 via the contact LCD of the switch 50 and the contact C of the switch 51 for display.

In the above embodiment, the type is determined from the image data in the determination circuit 52. However, the mixing information generated when the mixing circuit 41 executes the mixing process is described in FIG. As shown by the broken line in FIG. 7, the coefficient k may be supplied to the determination circuit 52, and the coefficient k may be generated by the determination circuit 52 in accordance with the mixed information.

The mixed information is supplied to the determination circuit 52 via a signal line different from the image data, or is subjected to time division multiplexing in the image data, for example, during a retrace interval, to divide the image data. The signal may be transmitted by a signal line to be transmitted.

In the above embodiment, the CRT and the LCD are used as the display.
A plasma display can be used as a fixed image display device instead of a CD.

[0093]

As described above, according to the image display control device according to the first aspect and the image display control method according to the third aspect, the output of the video camera is inversely gamma-corrected and the nonlinear characteristic of the display is reduced. Since the correction is performed, it is possible to suppress image deterioration when the output of the video camera is subjected to the interpolation filter processing.

According to the image display control device of the fourth aspect and the image display control method of the seventh aspect, the non-linear characteristic of the display is corrected corresponding to the connected display. It is possible to suppress the deterioration of the image when the output is subjected to the interpolation filter processing.

According to the image display control device and the image display control method of the present invention, it is determined whether the image is from a video camera or an image from a computer. Since the non-linear characteristic of the display is corrected in accordance with the result, it is possible to suppress the deterioration of the image due to the interpolation filter processing of the image data.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an image display control device according to the present invention.

FIG. 2 is a block diagram showing another configuration example of the image display control device of the present invention.

FIG. 3 is a block diagram showing another configuration example of the image display control device of the present invention.

FIG. 4 is a block diagram showing a configuration example when an LCD is connected as a display in the embodiment of FIG. 3;

FIG. 5 is a block diagram showing another configuration example of the image display control device of the present invention.

FIG. 6 is a block diagram showing still another configuration example of the image display control device of the present invention.

FIG. 7 is a block diagram showing a configuration example when an LCD is connected as a display in the embodiment of FIG. 6;

8 is a block diagram illustrating a configuration example of a switch 44 and a switch 51 in FIG.

9 is a waveform diagram illustrating the operation of the mixing circuit 41 of FIG.

FIG. 10 is a block diagram illustrating a configuration example of a conventional image display control device.

FIG. 11 is a diagram illustrating an example of an original image.

FIG. 12 is a diagram illustrating an example of an image obtained by enlarging an original image.

FIG. 13 is a diagram illustrating an example of a positional relationship between pixels of an original image and pixels of an enlarged image.

FIG. 14 is a diagram illustrating an example of an image obtained by increasing the resolution of an original image.

FIG. 15 is a diagram illustrating an example of an image obtained by reducing an original image.

FIG. 16 is a diagram illustrating an example of a positional relationship between pixels of an original image and pixels of a reduced image.

FIG. 17 is a diagram illustrating an example of an image in which the resolution of an original image is reduced.

FIG. 18 is a diagram illustrating an example of a positional relationship between pixels of an original image and pixels generated by interpolation.

FIG. 19 is a diagram illustrating an approximate interpolation function.

FIG. 20 is a diagram illustrating interpolation filter processing.

FIG. 21 is a diagram illustrating characteristics of gamma correction.

FIG. 22 is a block diagram illustrating another configuration example of a conventional image display control device.

FIG. 23 is a block diagram showing still another configuration example of the conventional image display control device.

FIG. 24 is a waveform diagram illustrating signal waveforms and sampling points.

FIG. 25 is a waveform diagram illustrating signal waveforms and sampling points.

FIG. 26 is a waveform diagram illustrating signal waveforms and sampling points.

FIG. 27 is a waveform diagram illustrating signal waveforms and sampling points.

[Explanation of symbols]

1 video camera, 2 gamma correction circuit, 3 A /
D conversion circuit, 4 inverse gamma correction circuit, 5 interpolation filter, 6 LCD characteristic correction circuit, 7 LCD, 8
D / A conversion circuit, 9 low-pass filter, 11
Computer, 12 gamma correction circuit, 14 CR
T, 15 D / A conversion circuit, 16, 31, low pass filter, 41 mixing circuit, 42 inverse gamma correction circuit, 45 interpolation filter, 46 LCD characteristic correction circuit, 48 gamma correction circuit, 49 LCD characteristic correction circuit, 52 judgment circuit

Claims (11)

[Claims] 1. An image display control device for displaying on a display an image of a subject which has been gamma-corrected and output from a video camera, comprising: an inverse gamma correction means for performing an inverse gamma correction on an output of the video camera; An image display control device comprising: a processing unit that performs interpolation filter processing on the display; and a display characteristic correction unit that corrects a nonlinear characteristic of the display. 2. The image display control device according to claim 1, wherein the display is an LCD or a plasma display. 3. An image display control method for displaying on a display an image of a subject which has been gamma-corrected and output from a video camera, comprising: an inverse gamma correction step of performing an inverse gamma correction on an output of the video camera; and an output of the video camera. An image display control method, comprising: a processing step of performing interpolation filter processing on the display; and a display characteristic correction step of correcting a nonlinear characteristic of the display. 4. An image display control device for displaying an image output from a computer on a display, comprising: a processing unit for performing an interpolation filter process on an output of the computer; and a non-linear characteristic of the display corresponding to the connected display. An image display control device comprising: a display characteristic correction unit that corrects an image. 5. The image display control device according to claim 4, wherein said display characteristic correction means selectively corrects nonlinear characteristics of at least two displays. 6. The image display control device according to claim 4, further comprising a limiting unit that limits an output band of the computer. 7. An image display control method for displaying an image output from a computer on a display, a processing step of performing an interpolation filter process on an output of the computer, and a nonlinear characteristic of the display corresponding to the connected display. And a display characteristic correcting step of correcting image characteristics. 8. An image display control device for displaying, on a display, an image in which an image of a subject output by gamma correction from a video camera and an image output from a computer are mixed, an interpolation filter process for the data of the mixed image. Processing means, and a determination means for determining whether the mixed image is an image from the video camera or an image from the computer, and in response to the determination result of the determination means, An image display control device, comprising: display characteristic correction means for correcting non-linear characteristics. 9. The display characteristic correction means, when the data of the mixed image is image data from the video camera, performs inverse gamma correction on the image data, and the data of the mixed image is image data from the computer. 9. The image display control device according to claim 8, wherein the image data is not subjected to inverse gamma correction. 10. When the data of the mixed image is image data from the computer, the display characteristic correction unit performs gamma correction on the image data, and the data of the mixed image is image data from the video camera. 9. The image display control device according to claim 8, wherein in some cases, the image data is not gamma-corrected. 11. An image display control method for displaying, on a display, an image in which an image of a subject output by gamma correction from a video camera and an image output from a computer are mixed, wherein an interpolation filter process is performed on the data of the mixed image. Processing step, a determination step of determining whether the mixed image is an image from the video camera or an image from the computer, and in response to the determination result of the determination step, A display characteristic correcting step of correcting a non-linear characteristic.