JP2002077724A - Method for reducion of display image and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of image quality accompanied with reduction of a picture. SOLUTION: Input image data S1 are band-limited by a band limiting part 10 for preventing the return of high band components accompanied with picture reduction prior to the reduction processing of the image by an image reduction processing part 20 where the band limit is made correspond to the reduction rate i so that resolution can be prevented from being irrationally deteriorated. Then, an outline signal S4 is extracted from reduced image data S3 from the image reduction processing part 20 by an outline extracting part 30, and level limiting is operated according to the reduction rate i by an outline level control part 40. The saturation is adjusted according to the image reduction rate i by a saturation adjusting part 50. An outline correction signal S5 is added to reduced image data S6 from the saturation adjusting part 50 by an adder 70 so that high band compensation can be performed as for the still image area of the input image S1, and the reduced image data S6 are outputted as they are while the high band compensation is not performed as for the moving image area of the input image S1 by using the movement information detected by a movement detector 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display such as monitor display and print display of an image, and more particularly, to a display method and an apparatus for displaying an image at a reduced size.

[0002]

2. Description of the Related Art An image can be easily processed by digitizing image data and performing digital signal processing. The most basic signal processing for a digitized image is to display the original image in an enlarged or reduced manner. For example, in a television receiver, which is called a multi-screen, there is a television receiver in which images of all channels are reduced and images of all channels are displayed on one display screen. In addition, in image display called picture-in-picture, the first
The second image is reduced and overlaid on the second image so that the two images can be viewed simultaneously.

FIG. 11 is a diagram showing an example of a picture-in-picture image display, in which the vertical size and the horizontal size of the second image are reduced by half with respect to the first image, respectively. 1 shows a display when the second image is overlaid.

[0004] A display form such as picture-in-picture is used not only for a moving image such as a television image but also for a still image when two images taken by a digital still camera are combined or printed. It is valid. Displaying a multi-screen or picture-in-picture image as described above requires image size reduction processing.

FIG. 12 is a block diagram showing a conventional example of a signal processing system for reducing an image size.

In FIG. 1, the signal processing system includes an image data input port 1, an image size reduction rate input port 2, a reduction mode instruction terminal 4, a band limiting unit 10 for limiting a signal band of an image signal. , An image reduction processing unit 20 that performs image size reduction processing, and an image data output port 5 that outputs reduced image data.

[0007] The image data input from the image data input port 1 is supplied to the band limiting unit 10. The band limiting unit 10 includes a shift register unit 11 including a plurality of registers R _{1 to} R ₆ and a multiplication unit 1 including a plurality of multipliers A 1 to A 7.
2, a fixed coefficient section 16 for supplying predetermined multiplier coefficients to the multipliers A _{1 to} A ₇ , and an adder 14 for adding a plurality of signals output from the multiplier section 12.

Generally, when reducing the image size,
This is performed by thinning out the constituent data (pixel data) of the image from the original image data. However, if the image size is reduced by simply thinning out the pixel data, the high-frequency components of the image will be turned back and become noise, resulting in a decrease in image quality. become. To prevent this, it is necessary to perform band limitation (filtering) on the original image data before performing image reduction processing. That is, the band limiting unit 10 performs a filtering process for removing unnecessary bands in order to suppress such aliasing noise.

Therefore, in the band limiting section 10, the image data is first supplied to the shift register section 11, and the image data is shifted by a predetermined timing (period of a pixel) in each of the registers R _{1 to} R _6. , the register a ₁ at that time the shift register unit 11 pixel data multiplication section 12 to be input to, and the pixel data output from the register R ₁ to R ₆ of the shift register 11 of the multiplication unit 12 the multiplier a They are respectively supplied to the ₂ ~A _7.

On the other hand, when information for instructing the image reduction mode is input from the reduction mode instruction terminal 4 and supplied to the fixed coefficient section 16, the fixed coefficient section 16 is determined in advance to allow the band-limiting filter to function. the filter coefficient is supplied to the multiplication unit 12, by which the multiplication coefficient corresponding to the filter coefficients respectively are distributed to the appropriate multiplier a ₁ to a ₇ in the multiplier unit 12. Therefore, these in the multiplier A ₁ to A _7, respectively, the multiplication processing of the pixel data supplied from the shift register unit 11 and the multiplication coefficient is carried out, each multiplier A ₁
The output signal of the to A ₇ are the addition operation is supplied to the adder 14 is performed.

[0011] By such signal processing, a filter characteristic for limiting a band is obtained. That is, the output signal of the adder 14 is a signal whose image band is limited as compared with the image signal input from the image data input port 1.

FIG. 13 is a characteristic diagram showing an example of a band limiting characteristic obtained by the band limiting section 10. In this example, a band characteristic curve of input image data (reduction rate 100
%), The band of the band limiting characteristic is limited to ４. According to this, the image size is reduced by 25%.
Even if the size is reduced to the above, the aliasing noise of the high frequency component can be suppressed.

Returning to FIG. 12, the image data band-limited by the band-limiting unit 10 is supplied to the image reduction processing unit 20. The image reduction processing unit 20 includes a decimation unit 21, a reduced image data memory 22 for storing thinned image data, and a memory control unit 23 for generating a control signal for controlling the reduced image data memory 22. It is composed of

In the image reduction processing unit 20, first, the image data subjected to the band limitation is processed in the decimation unit 21. The decimation unit 21 thins out a part of the image data supplied in accordance with the information (image reduction ratio information) indicating the image reduction ratio input from the reduction ratio input port 2 at a predetermined timing, and outputs the next reduced image data. The data is supplied to the memory 22.

FIG. 14 is a timing chart showing an example of the decimation process when the image reduction ratio is 75%.

FIG. 14A shows a horizontal pixel space (P) of an original image (that is, band-limited image data from the band limiting unit 10). Pixels a, b, c, d, e, f, g,.
... is shown. The decimation unit 21 performs a process of thinning out one pixel for every predetermined number of pixels in the pixel array. Here, it is assumed that one pixel is thinned out every four pixels, and the pixels c, g is indicated by hatching.

FIG. 14B shows the time series (Q) of the pixel data of the original image. FIG. 14C shows the time series (Q) of the pixel data of the original image.
1 shows a time series (R) of the pixel data of the reduced image in which the pixel data is thinned out according to the thinning procedure in the pixel space (P) shown in FIG. In this time series (R), a hatched portion is a portion where pixel data is thinned out. The time-series (R) image data is stored in the reduced image data memory 22 in FIG. FIG. 14D shows the data (S) stored in the reduced image data memory 22.

The image data subjected to the decimation process in the decimation section 21 is stored in the reduced image data memory 22.
Writing to and reading image data from the reduced image data memory 22 is controlled by a control signal generated by the memory control unit 23. The memory control unit 23
75% image reduction ratio information is obtained from the reduction ratio input port 2,
The reduced image data memory 22 according to the image reduction rate information
A control signal for controlling the writing / reading of is generated. Thus, from the reduced image data memory 22, the image data of the image compressed to a 75% image size is thinned out by one pixel every four pixels in accordance with the display timing of the reduced image on the display screen (not shown). The data is read out and output from the image data output port 5.

By performing the above signal processing, the original image data is reduced from the original image size to the specified image size. Therefore, such a reduction processing method is applied to a picture-in-picture display as shown in FIG.

[0020]

In general, the frequency components of image data are not infinite, but have a finite frequency band due to restrictions on the number of pixels of a television camera or digital still camera that generates image data and transmission paths. ing. For this reason, high frequency components of the image data are compensated (for example,
The lack of resolution is visually compensated by sharpening the image by contour enhancement.

However, in the above-described conventional image reduction display method, naturally, the high frequency components of the image are removed by the band limiting filter, so that the processing effect of the edge enhancement is also eliminated. Therefore, by performing the above-described image reduction processing display, a visual reduction in resolution is more remarkably recognized than the specified image reduction ratio.

Further, as described above, since the filter coefficient of the filter characteristic for band limitation is fixed, the band of the image signal may be narrowed more than necessary depending on the reduction ratio of the image size, and the resolution may be reduced. It becomes more noticeable. In particular,
In order to display two images simultaneously on a display screen, in a case where the size of one image is reduced and the other image is overlaid, the resolution of the reduced image is significantly reduced.
There will be an imbalance in image quality between these two images displayed simultaneously.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, to prevent a decrease in image quality due to image reduction, and to maintain a high-quality image of a reduced image, and a method and apparatus for displaying a reduced image. Is to provide.

[0024]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a band limiting means for limiting the bandwidth of image data in accordance with a reduction rate of an image size, and an image data passing through the bandwidth limiting means. Image reduction processing means for thinning out data in accordance with the reduction rate, contour extraction means for extracting an outline component of an image from the image data obtained by the image reduction processing means, and a contour signal level in accordance with the reduction rate of the image size. Contour level control means for controlling, saturation adjustment means for adjusting the saturation of the image data obtained by the image reduction processing means according to the reduction ratio of the image size, and level adjustment for the reduced image after the saturation adjustment And an adder for adding the obtained contour signal, and the adder can be controlled by the motion information detected by the image motion detector.

With this configuration, when displaying an image that has been subjected to reduction processing, high-frequency compensation and saturation compensation are performed on the reduced image in accordance with the reduction ratio of the designated image size. A high-frequency compensation is applied to the reduced image in order to compensate for a decrease in the visual resolution due to the reduction processing, and such high-frequency compensation is stopped at the outline portion in the moving region of the reduced image. As a result, it is possible to prevent the afterimage that occurs when the high-frequency compensation is performed, and to eliminate a sense of incongruity (afterimage effect) that occurs in the outline portion of the moving image area of the image.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of an image reduction display method and apparatus according to the present invention, wherein 1 is an image data input port, 2 is a reduction rate input port, 3 is an image data output port, Is a band limiting unit, 20 is an image reduction processing unit, 30 is an outline extraction unit, 40
Is an outline level control unit, 50 is a saturation adjustment unit, 60 is a motion detector, and 70 is an adder.

In FIG. 1, image data S ₁ is inputted from an image data input port 1 and a reduction ratio input port 2
From this image data S ₁ given an image of a predetermined size image reduction ratio for the (specified image size) i (where, 0% <i ≦ 100% ) is input. The input image data S ₁ from the image data input port 1 is supplied to the band restriction unit 10 and the motion detector 60. The band limiting unit 10, with the filter coefficient corresponding to the image reduction ratio i input from the reduction ratio input port 2, filtering band limitation is performed on the input image data S _1. Filtered image data S ₂ is supplied to the image reduction process unit 20, the reduction processing according to the image reduction ratio i is made, data of images reduced in size by the image reduction ratio i (reduced image data) S ₃ is formed.

[0028] Also, the motion detector 60, from the difference between the input image data S ₁ frame, the input image data S ₁ is when the data of a moving image, the motion information S ₇ is detected.

The reduced image data S ₃ output from the image reduction processing section 20 is supplied to a contour extracting section 30 and a contour signal S ₄ representing a contour portion of the reduced image based on the reduced image data S ₃ is extracted. The contour signal S ₄ is supplied to the contour level control unit 40, the level of which is adjusted according to the image reduction ratio i input from the reduction ratio input port 2, and supplied to the addition unit 70 as a contour correction signal S _5. Is done.

The reduced image data S ₃ output from the image reduction processing unit 20 is also supplied to a saturation adjustment unit 50, and the saturation level is adjusted according to the image reduction ratio i. The reduced image data S ₆ output from the saturation adjustment unit 50 is added to an adder 7.
0 is supplied. In the adder 70, further motion information S ₇ is supplied from the motion detector 60, the motion information S
_{According to 7} , the addition processing of the reduced image data S ₆ from the saturation adjustment unit 50 and the contour portion correction signal S ₅ from the contour level control unit 40 is performed. Reduced image data S ₈ output from the adder 70 is supplied to an image display such as a monitor display or print the display.

Next, each component in FIG. 1 will be described.

FIG. 2 is a block diagram showing a specific example of the band limiting section 10 and the image reduction processing section 20 in FIG. 1. Reference numeral 13 denotes a filter coefficient generation section, reference numeral 15 denotes a center of gravity correction processing section, and FIG. The same reference numerals are given to the portions corresponding to and the duplicate description will be omitted.

In FIG. 1, a band limiting unit 10 includes a shift register unit 11 including a plurality of registers R _{1 to} R _6, a multiplying unit 12 including a plurality of multipliers A _{1 to} A _7, and a specified predetermined signal. A filter coefficient generator 13 that generates a filter coefficient according to an image reduction ratio i for setting an image size, and an adder 14 that adds outputs of the multipliers A _{1 to} A ₇ of the multiplier 12.
And a center-of-gravity correction processing unit 15 for correcting a pixel center-of-gravity shift generated in the decimation process of the decimation unit 21 in the image reduction processing unit 20.

The input image data S ₁ from the image data input port 1, the band limiting section 10, by a shift register unit 11 and the multiplication unit 12 and the adder 14, the band-limited image as described in FIG. 12 Filter processing is performed. At this time, the multiplication coefficients (filter coefficients) of the multipliers A _{1 to} A ₇ of the multiplication unit 12 are in accordance with the image reduction ratio i input from the reduction ratio input port 2. , This image reduction ratio i
Is generated by the filter coefficient generation unit 13 to which is supplied.

FIG. 3 is a characteristic diagram showing a specific example of the band limiting characteristic formed by the band limiting unit 10. As shown in the figure, the filter coefficient generating unit 13 operates as the image reduction ratio i decreases. The band limiting characteristic of the image is F ₀ (when the image reduction ratio i = 100% and is not reduced) → F ₁ (when the image reduction ratio i = 75%) → F ₂ (when the image reduction ratio i = 50%) → A filter coefficient such as F ₃ (when the image reduction ratio i is 25%) that narrows the bandwidth is generated.

Returning to FIG. 2, the image data from the adder 14 that has been subjected to the filtering process as described above is supplied to the centroid correction processing unit 1.
5 for performing a process for correcting a shift in the center of gravity of the image caused by the pixel data thinning performed by the decimation unit 21 in the image reduction processing unit 20.

FIG. 4 is a diagram showing the relationship between the center-of-gravity correction processing in the center-of-gravity correction processing unit 15 and the decimation processing in the decimation unit 21 when the image reduction ratio i is 75% as an example.

FIG. 4A shows the pixel space of the image based on the filtered image data from the adder 14 (FIG. 2), that is, the pixel space (A) of the original image before reduction. Pixels arranged in the horizontal direction are represented by a, a,
b, c, d, e, f, g, h,... In this case, since the image reduction ratio i is 75%, in the pixel space (A) of the original image, one pixel is thinned out every four pixels.

FIG. 4B shows the pixel space of the image based on the reduced image data obtained by the decimation process in the decimation unit 21, that is, the pixel space (B) of the reduced image. In (B), image reduction processing (decimation processing) is performed such that three pixels are generated by weighting from four pixels in the pixel space (A) of the original image. Now, the relationship between the four pixels a, b, c, and d in the pixel space (A) of the original image and the three pixels a ′, b ′, and d ′ in the pixel space (B) of the reduced image is as follows. '= (2a + b) / 3 b' = (b + 2c) / 3
A weighting operation is performed so that d ′ = d, and a reduction process is performed, and this process is performed for every four pixels in the pixel space (A) of the original image.

FIG. 4 (c) shows an array of pixel data in the image data before being reduced after being subjected to the filtering process from the adder 14 (FIG. 2). ), And the pixel data a, b, c,.
Are arranged in the order corresponding to the pixels a, b, c,... In the pixel space (A) of the original image shown in FIG.

Here, with reference to the specific example shown in FIG. 5, the processing operation of the center-of-gravity correction processing unit 15 when the image reduction ratio i is 75% will be described.

In the center-of-gravity correction processing unit 15, the image data of the time series (C) of the original image shown in FIG.
Thus, the image data of the delay time series (C ′) as shown in FIG. 4D is generated. The time series (C) image data of the original image is supplied to a multiplier 15b and multiplied by a coefficient α, and the delayed time series (C ′) image data is supplied to a multiplier 15c and multiplied by a coefficient β. You.

Here, when the image reduction ratio i is 75%, the multiplier 15b uses the four pixel data of the image data of the time series (C) and the delay time series (C ') of these original images as one processing unit. In this processing unit, the coefficient α is switched to 1/3, 2/3, 0, 0 every time pixel data of the image data of the time series (C) of the original image is supplied, and is synchronized with this. In the multiplier 15c, the coefficient α is switched to /, /, 0, 1 every time pixel data of the image data of the delay time series (C ′) is supplied in the same processing unit. . Then, the switching of the coefficients α and β is repeated for each processing unit. The image data output from the multipliers 15b and 15c are added by the adder 15d, and the band limiter 1
The output image data S ₂ of 0 is supplied to the decimation unit 21 of the image reduction processing unit 20.

Therefore, the multiplier 15 is used for a certain processing unit.
Assuming that pixel data in the time series (C) image data of the original image supplied to b is b, c, d, and e shown in FIG. 4C, the delay supplied to the multiplier 15b in this processing unit The pixel data in the image data of the time series (C ′) are a, b, c, and d shown in FIG. 4D, and the time series (C) of the original image, which is the first pixel data in this processing unit, The pixel data b of the delay time series (C ′) and the pixel data a of the
Is multiplied by the coefficient 1/3 by the multiplier 15c, and is multiplied by the coefficient 2/3 by the multiplier 15c, and is added by the adder 15d.
, Pixel data of (2/3) a + (1/3) b is obtained. Pixel data c in the time series (C) of the original image, which is the second pixel data in this processing unit
And the pixel data b in the delay time series (C ′)
5b, the coefficient 2/3 is multiplied by the multiplier 15c, and the coefficient 1/3 is multiplied by the adder 15d.
From (5d), pixel data of (1/3) b + (2/3) c is obtained. The pixel data d in the time series (C) of the original image, which is the third pixel data in this processing unit, and the pixel data c in the delay time series (C ′) are respectively
Since the coefficient 0 is multiplied by the multiplier 15b and the coefficient 0 is multiplied by the multiplier 15c and added by the adder 15d, pixel data of 0 · c + 0 · d is obtained from the adder 15d. The pixel data e in the time series (C) of the original image, which is the last pixel data in the processing unit, and the pixel data d in the delay time series (C ′) are each multiplied by a coefficient 0 in the adder 15b. Since the coefficient 1 is multiplied by the adder 15c and added by the adder 15d, pixel data of 1 · d + 0 · e is obtained from the adder 15d. Such processing is repeated for each processing unit.

As described above, from the adder 15d,
Image data S ₂ of the array of pixel data representing a time series (D) of the reduced image obtained in FIG. 4 (e), which although being supplied to the decimation section 21 in FIG. 2, this decimation section 21 The image data S ₂ is thinned out by one pixel data for each of the above processing units and written to the reduced image data memory 22.

Here, the pixel data thinned out for each of the processing units in the image data S ₂ is the above (0 · c + 0 · d) pixel data when the above processing is performed. This is shown by hatching in FIG. The center-of-gravity correction processing unit performs such thinning-out of pixel data in the decimation unit 21 so as to coincide with the timing when the coefficients α and β in the multipliers 15b and 15c shown in FIG. The thinning timing in the decimation unit 21 is set in synchronization with the operation of No. 15.

In the decimation unit 21, the number of horizontal scanning lines of an image reduced at the image reduction ratio i is reduced according to the image reduction ratio i. For this reason, the decimation unit 21 also performs thinning of the horizontal scanning lines. For example, when the image reduction ratio i is 75%, the decimation unit 2
At 1, one horizontal scanning line is thinned out every four horizontal scanning lines.

In FIG. 2, image data thinned out by the decimation unit 21 is stored in a reduced image data memory 22.
At this time, the writing of the reduced image data memory 22 is controlled by the memory control unit 23 so that the pixel data to be thinned out is not written. Therefore, image data is stored in the reduced image data memory 22 as shown in FIG. 4F as data (E) of the reduced image data memory.

From the reduced image data memory 22, according to the control signal from the memory control unit 23, the written pixel data is arranged in the same order as at the time of writing and at a constant regular interval in accordance with the timing of the reduced image display. (i.e., the normal of the pixel period of the video signal) becomes the pixel array, and read out as the period of each horizontal scanning line is equal to the period of the normal horizontal scanning lines, an output terminal as the reduced image data S ₃ 24
Are supplied to the contour extraction unit 30 and the saturation adjustment unit 50 shown in FIG.

As described above, by the band limiting unit 10 and the image reduction processing unit 20, the reduced image data S ₃ in which the aliasing noise of the high frequency component and the displacement of the center of gravity of the pixels due to the decimation process of the original image are suppressed is obtained. can get.

Here, since the description has been given of an example in which the image reduction ratio i is 75%, the multiplication coefficients in the center-of-gravity correction processing unit 15 are shown in FIG. The reduction ratio i can be arbitrarily set (0% <i ≦ 100%). Therefore, it goes without saying that the multiplication coefficient differs depending on the set image reduction ratio i (for example, When the image reduction ratio i is 50%, the multiplication coefficient in FIGS. 4 and 5 is fixed to 、 and the decimation unit 21 may thin out every other pixel data.)

FIG. 6 is a block diagram showing a specific example of the motion detector 60 in FIG.
Denotes a frame memory, 63 denotes a subtractor, 64 denotes an absolute value processing unit, and 65 denotes a clip processing unit.

In the figure, image data input port 1
The input image data S ₁ from FIG. 1 is also supplied from the input terminal 61 to the motion detector 60. In the motion detector 60, the input image data S ₁ is supplied to the subtractor 63, and is also delayed by one frame time in the frame memory 62 and supplied to the subtractor 63. Therefore, this subtractor 6
In 3, the current frame of the input image data S ₁ and its 1
Difference data from the immediately preceding frame is extracted. As the difference data obtained from subtractor 63, if the image data of the input image data S ₁ is still image, is zero, if the moving image data, a significant (motion) signal is obtained. The difference data from the subtractor 63 is used as the absolute value processing unit 6
4, the absolute value of the difference value is obtained for each pixel, and the obtained absolute value signal is further processed by the clip processing unit 6.
5 and is clipped at a predetermined level. Thus, the output terminal 66, the effective motion control signal is obtained as the motion information S _7. Motion information S ₇ obtained by the above process can be utilized to control which will be described later.

FIG. 7 is a block diagram showing a specific example of the contour extraction unit 30 in FIG.
32 and 33 are delay circuits, 34 is an adder, 35 is an attenuator,
36 is a subtractor and 37 is an output terminal.

In the figure, the contour extracting section 30 is composed of two delay circuits 32 and 33, an adder 34, an attenuator 35 and a subtractor 36.

Next, the operation of this specific example will be described with reference to FIG. 8 showing the timing relationship of the data of each section in FIG.

The reduced image data S ₃ is input to the input terminal 31 from the image reduction processing unit 20 (FIGS. 1 and 2) as data J.
Supplied. The reduced image data J is directly added to the adder 34.
, And is delayed by 2D by two delay circuits 32 and 33 each having a delay amount D for one pixel period.
The delayed image data L is supplied to the adder 34. These reduced image data J and 2 output from the adder 34
The level of the added image data with the D delayed image data L is attenuated to 減 衰 by the attenuator 35. Therefore, from the attenuator 35, the average reduced image data M including the pixels of the average level of the pixel level of the input reduced image data J and the level of the pixel two pixels before this is obtained.

The average reduced image data M is supplied to the subtractor 36. Then, the 1D delayed image data K output from the first-stage delay circuit 32 is also supplied to the subtractor 36,
Then, the average reduced image data M is subtracted, and the outline component N of the image based on the reduced image data J is extracted. This contour component N is used as a contour signal S ₄ as a contour level control unit 40.
(FIG. 1).

[0059] Here, since the delay amount D of the delay circuits 32 and 33 is 1 pixel period, the contour signal S ₄ is representative of the contour of the horizontal direction of the image.

FIG. 9 shows the contour level control unit 40 shown in FIG.
Is a block diagram showing a specific example, wherein 41 and 42 are input terminals, 43 is a normalization unit, 44 is a multiplier, and 45 is an output terminal.

In the figure, the contour level control unit 40
It comprises a normalizing unit 43 for normalizing the input image reduction ratio i and a multiplier 44.

The contour signal S ₄ extracted as described above by the contour extracting section 30 is input from the input terminal 41 and supplied to the multiplier 44, where the multiplication coefficient (relative reduction coefficient) corresponding to the image reduction rate i is provided. by γ is multiplied, is adjusted to the desired level is output from the output terminal 45, is level adjusted is supplied to the adder 70 as a contour correction signal S _5.

Here, the relative reduction coefficient γ is obtained by normalizing the image reduction ratio i input from the input terminal 42 by the normalization unit 43. For example, 100% ≧ i> 75%, relative reduction coefficient γ = 1.0 75% ≧ i> 50%, relative reduction coefficient γ = 1.25 50% ≧ i> 25%, relative reduction coefficient γ = 2 When 0.025% ≧ i> 0%, the relative reduction coefficient γ = 3.0.

[0064] Figure 10 is a graph showing the relationship between the relative reduction factor for varying the level of the image reduction ratio i specified contour correction signal S ₅ gamma, here, shows an example of the I have.

[0065] As shown in the figure, the relative reduction factor γ has a along the standardization of the designated image reduction ratio i characteristic, the level of the contour correction signal S ₅ in accordance with the image reduction ratio i becomes smaller Increases.

When the image reduction ratio i is normalized, the image reduction ratio i is finely divided so that the optimum value of the relative reduction coefficient γ is made to correspond to each division.
, It is possible to control the level of the contour signal with higher accuracy. However, when the image reduction ratio i smaller than the predetermined image size is designated, the level of the contour signal is saturated.

Returning to FIG. 1, the reduced image data S ₃ from the image reduction processing unit 20 is also supplied to the saturation adjustment unit 50, and saturation adjustment (saturation level) according to the designated image reduction ratio i is performed. Control). The level control of the color saturation, similarly to the level control of the contour signal S ₄ of the image, the image reduction ratio i
Is controlled so as to increase the saturation of the image as becomes smaller. As the image reduction ratio becomes smaller, the flat portion of the image becomes smaller and the color becomes less noticeable.However, by controlling the color according to the image reduction ratio in this way, the vividness of the color in the flat portion of the image is reduced. Is conspicuous, and the image quality of the reduced image is improved.

The reduced image data S ₆ whose saturation has been adjusted by the saturation adjusting section 50 is supplied to the adder 70. In the adding unit 70, the reduced image data S subjected to the saturation adjustment by the saturation adjustment unit 50
The high-frequency component of ₆ compensated for by the level adjustment contour portion correction signal S ₅ by the contour level controller 40, the high-frequency component by but in which visually compensate for the lack of resolution, such contour correction signal S ₅ compensation when the input image data S ₁ is an image data of a still image, and be image data of a moving image is performed for the still image area.

That is, the adder 70 is supplied with the motion information S ₇ detected by the motion detector 60. The motion information S ₇ determines whether the image of the input image data S ₁ is a still image area. Since the motion detector 60 determines whether the image is a moving image region or not, the motion detector 60 determines that the image is a still image without detecting the motion of the image. S ₅ is directly added to the reduced image data S ₆ which is the saturation adjustment. As a result, the still image area of the reduced image is compensated for in the high frequency range. Of course, if the image of the input image data S1 is a still image, because its entirety a still picture region, the contour portion correction signal S ₅ whose level is controlled in accordance with the image reduction ratio i is added to the entire High-frequency compensation. When the motion of the image is detected by the motion detector 60 and the image is determined to be a moving image area, the adder 7
0, in this video area, without adding a contour portion correction signal S ₅ to the reduced image data S ₆ that the saturation adjustment at saturation adjustment unit 50, and outputs it. Thus, the motion information S of the image
Depending on the _7, mixing of the contour portion correction signal S ₅ (i.e.,
High-frequency compensation of the reduced image) is controlled.

[0070] Thus, by adding the contour correction signal S _5, although a high-frequency is compensated are those attained visually Supplementary improved image quality the shortage of resolution, the motion picture region, such By stopping the high-frequency compensation, it is possible to prevent the emphasized contour from giving an unnatural feeling due to the afterimage effect.

In this embodiment, only the method of reducing and displaying the image size in the horizontal space of the image has been described. However, in the case of the vertical direction, the processing is performed in the same manner as in the horizontal direction, so that the image is displayed in the vertical direction. Can be reduced in size. That is, in the decimation unit 21 in FIG. 2, thinning is performed simultaneously in units of horizontal scanning periods according to the image reduction ratio i (for example, when the image reduction ratio i is 75%, one horizontal scanning period is performed every four horizontal scanning periods). The thinning process is performed each time), and the delay amount D of the delay circuits 32 and 33 has the same configuration as that of the contour extraction unit 30 shown in FIG.
The provided contour extraction unit for extracting a vertical contour component to one horizontal scanning period, extracts a vertical edge component of the reduced image data S ₃ from the image reduction processing section 20, the contour extraction unit 30 so is added to the edge signal S ₄ that is output from that is supplied to the contour level controller 40.

By performing the above-described image reduction display method, the image reduction ratio i for obtaining the designated image size is obtained.
In order to restrict the band of the original image according to, the aliasing noise of the high-frequency component due to the decimation is suppressed, the image band is not unnecessarily narrowed, and the reduction in the resolution due to the reduction in the image size is also minimized. be able to.

Even though the bandwidth of the image is reduced by the image size reduction process, high-frequency compensation according to the image reduction ratio i is performed, so that a visual decrease in resolution is alleviated.

Further, since the saturation of the reduced image is also adjusted according to the image reduction ratio i, the vividness of the color in the flat portion of the image is enhanced, and the image quality of the reduced image is improved.

In the above-described embodiment, the configuration is such that the motion information of the image is detected from the input image data S _1. However, the motion detector 60 is installed at the subsequent stage of the image that from the signal S ₃ may be configured to detect the motion information, of course.

[0076]

As described above, according to the present invention,
When performing monitor display or print display by reducing the image size, the amount of compensation for the high-frequency component (detail) of the reduced image is controlled in accordance with the specified image reduction ratio. Can be visually corrected.

According to the present invention, when performing monitor display or print display by reducing the image size, the saturation of the reduced image is adjusted according to the specified image reduction ratio. Is enhanced according to the reduction ratio of the image size.

Further, according to the present invention, control is performed so as to stop the detail compensation of the moving area portion of the image by using the motion information of the image. ) Can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an image reduction display method and apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a specific example of a band limiting unit and an image reduction processing unit in FIG. 1;

FIG. 3 is a diagram illustrating an example of band limiting characteristics formed by a band limiting unit in FIG. 2;

FIG. 4 is a diagram illustrating processing when the image reduction ratio of the center-of-gravity correction processing unit and the decimation unit in FIG. 2 is 75%.

FIG. 5 is a block diagram illustrating a specific example of a center-of-gravity correction processing unit in FIG. 2;

FIG. 6 is a block diagram showing a specific example of a motion detector in FIG. 1;

FIG. 7 is a block diagram illustrating a specific example of a contour extraction unit in FIG. 1;

FIG. 8 is a timing chart showing an operation of the contour extraction unit shown in FIG. 7;

FIG. 9 is a block diagram showing a specific example of an outline level control unit in FIG. 1;

10 is a control characteristic diagram showing a level change of an outline signal according to an image reduction ratio in the outline level control unit shown in FIG. 9;

FIG. 11 is a diagram illustrating a picture-in-picture image display example.

FIG. 12 is a block diagram illustrating an example of a conventional image reduction display method and a band limiting unit and an image reduction processing unit in the apparatus.

FIG. 13 is a diagram illustrating band limiting characteristics of a band limiting unit in FIG. 12;

FIG. 14 is a diagram illustrating the decimation process when the image reduction ratio in the decimation unit in FIG. 12 is 75%.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image data input port 2 Reduction rate input port 3 Image data output port 10 Band limiting unit 11 Shift register unit 12 Multiplication unit 13 Filter coefficient generation unit 14 Adder 15 Center of gravity correction processing unit 20 Image reduction processing unit 21 Decimation unit 22 Reduced image Data memory 23 Memory control unit 30 Contour extraction unit 32, 33 Delay circuit 34 Adder 35 Attenuator 36 Subtractor 40 Contour level control unit 43 Normalization unit 44 Multiplier 50 Saturation adjustment unit 60 Motion detector 62 Frame memory 63 Subtraction Unit 64 absolute value processing unit 65 clip processing unit 70 adder

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Claims (8)

[Claims] 1. A display method for reducing an image size and performing monitor display or print display, wherein, in a still region of the image, an enhancement amount or reduction of a detail component included in the reduced image according to a reduction ratio of a specified image size. A method for reducing the size of an image, comprising controlling the saturation of the image. 2. The method according to claim 1, wherein as the reduction rate of the designated image size is reduced, control is performed to increase the amount of enhancement of detail components included in the reduced image or to increase the saturation of the reduced image. How to reduce the size of the image. 3. A display method for reducing a size of an image and performing monitor display or print display, wherein in a moving area of the image, an enhancement amount of a detail component included in the reduced image is included in accordance with a reduction ratio of a designated image size. A reduced display method for an image, wherein only the saturation of the reduced image is controlled without performing control. 4. The reduced image display method according to claim 3, wherein the saturation is increased as the reduction ratio of the designated image size is reduced. 5. An image display apparatus for reducing an image size and performing monitor display or print display, comprising: a band limiter for applying a band limit to input image data in accordance with an image size reduction ratio; An image reduction processing unit that performs a thinning process according to the reduction ratio of the image size on the image data thus generated to generate reduced image data; a contour extraction unit that extracts a contour signal of an image from the reduced image data; An outline level control unit that controls the level of the outline signal according to the image size reduction ratio; and a color adjustment unit that adjusts the saturation of the reduced image data obtained by the image reduction processing unit according to the image size reduction ratio. A degree adjusting unit; an adder for adding the contour signal whose level has been adjusted by the contour level control unit to the reduced image data having undergone the saturation adjustment; and a motion detector for detecting motion information of an image from the input image data. It includes a vessel, and said adder, reduced display of an image, characterized in that it is controlled by the motion information detected by the motion detector. 6. The reduced image display device according to claim 5, wherein the outline level control unit performs control to increase the level of the outline signal as the reduction ratio of the image size decreases. 7. The image processing apparatus according to claim 5, wherein the saturation adjustment unit performs control to increase the saturation of the reduced image data obtained by the image reduction processing unit as the reduction ratio of the image size decreases. A featured image reduction display device. 8. The contour level control unit according to claim 5, wherein the adder controls a level of the reduced image data from the saturation adjustment unit when the motion information from the motion detector indicates a moving area. An image reduction display device, wherein the addition of the adjusted contour signal is stopped and the reduced image data is output from the saturation adjustment unit.