JP2004266757A - Image processing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus and method capable of adjusting the contrast of each of multi-images in the case of displaying a plurality of the multi-images on one image screen. <P>SOLUTION: A S/T separation circuit 51 separates a luminance signal Y<SB>IN</SB>into a structure component S1 and a texture component T1. A structure correction circuit 53 corrects the structure component S1 to generate a structure component S2. A texture amplifier circuit 52 amplifies the texture component T1 to generate a texture component T2. A switch 54 selects the texture component T1 or the texture component T2 on the basis of a DE signal supplied from a multi-screen processing part 14 and supplies the selected texture component to an adder 55. The adder 55 acquires the texture component from the switch 54 and summates the texture component to the structure component S2. The image processing apparatus and method is applicable to television receivers. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing apparatus and method, and more particularly, to an image processing apparatus and method capable of adjusting contrast for each multi image when displaying a plurality of multi images on one screen.
[0002]
[Prior art]
The image processing apparatus has, for example, functions such as adjustment of brightness and contrast, contour correction, and the like as an image processing function of performing image quality correction on an input image and outputting the image.
[0003]
For example, Patent Document 1 proposes an image processing apparatus having an image processing function that automatically determines the degree of contrast enhancement from the spread amount of a luminance distribution and allows a user to easily enhance contrast by an appropriate amount. I have.
[0004]
Further, a contrast enhancement method has been proposed in which a histogram of an input image signal is obtained to enhance the contrast of an image.
[0005]
[Patent Document 1]
JP-A-10-208044
[0006]
[Problems to be solved by the invention]
By the way, in recent years, a television receiver having a multi-screen display function of simultaneously displaying a plurality of reduced images on one screen has been sold.
[0007]
When displaying a multi-screen on a television receiver, the image processing function described in Patent Document 1 has a problem that contrast cannot be enhanced for each reduced image.
[0008]
Further, in the above-described contrast enhancement method, in order to enhance the contrast for each reduced image, it is necessary to take a histogram for each reduced image.
[0009]
The present invention has been made in view of such a situation, and it is an object of the present invention to easily and quickly adjust the contrast for each reduced image when displaying a multi-screen.
[0010]
[Means for Solving the Problems]
The image processing apparatus of the present invention separates input image data including data of a plurality of multi-images displayed simultaneously on one screen into a structure component forming a contour of the multi-image and a texture component forming details of the multi-image. Data separating means, texture enhancing means for enhancing the texture components separated by the data separating means, structure correcting means for performing non-linear correction on the structure components separated by the data separating means, and texture enhancing means Selecting means for selecting any one of the texture component emphasized by the above and the non-emphasized texture component, the structure component corrected by the structure correcting means, and the texture emphasized by the texture enhancing means selected by the selecting means Synthesize texture components to generate processed data And means, on the basis of the machining data combined by the combining means, characterized in that it comprises a display control unit that controls to display a plurality of multi-image on a single screen.
[0011]
The image processing apparatus may further include a frame signal output unit that outputs a frame signal indicating that the frame is the multi-image frame.
[0012]
When the frame signal output unit outputs a frame signal indicating that the frame is a multi-image frame, the selection unit may select an unemphasized texture component and supply the texture component to the synthesis unit.
[0013]
The frame signal output means may output a frame signal indicating that the frame is a multi-image frame when the image display period is not the multi-image image display period.
[0014]
The frame signal output means may output a frame signal indicating that the frame is a multi-image frame during an image display period of the multi-image and within a predetermined range near an edge of the multi-image. Can be.
[0015]
According to the image processing method of the present invention, input image data including data of a plurality of multi-images simultaneously displayed on one screen is separated into a structure component constituting an outline of the multi-image and a texture component constituting details of the multi-image. A data separation step, a texture enhancement step for enhancing texture components separated by the data separation step, and a structure correction step of performing non-linear correction on the structure components separated by the data separation step. A selection step of selecting one of a texture component enhanced by the processing of the texture enhancement step and a texture component not enhanced, a structure component corrected by the processing of the structure correction step, and a processing of the selection step. The selected texture component A combining step of combining and generating processed data; and a display control step of controlling a plurality of multi-images to be displayed on a single screen based on the processed data combined by the processing of the combining step. And
[0016]
In the image processing apparatus and method according to the present invention, input image data is separated into a structure component and a texture component, the texture component is emphasized, and the structure component is subjected to nonlinear correction. Then, one of the emphasized texture component and the non-emphasized texture component is selected, and the corrected structure component and the selected texture component are combined to generate processed data, and the processed data is generated based on the processed data. Thus, a plurality of multi-images are controlled to be displayed on one screen.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a block diagram illustrating a configuration example of a television receiver 1 to which the present invention has been applied.
[0019]
The television receiver 1 includes an image processing unit 2 that receives broadcast radio waves and demodulates a signal of a predetermined channel, and a display 3 that displays an image based on the demodulated signal.
[0020]
The tuners 11A and 11B of the image processing unit 2 receive television signals of different channels (programs) in a time-division manner, demodulate them, and output a composite signal (CVBS: Composite Video Burst Signal). The Y / C separation circuits 12A and 12B obtain composite signals from the corresponding tuners 11A and 11B, and convert the composite signals into luminance signals Y and C, respectively. ₁ And color signal C ₁ (Y / C separation circuit 12A), luminance signal Y ₂ And color signal C ₂ (Y / C separation circuit 12B). The chroma decoder 13A outputs the luminance signal Y ₁ And color signal C ₁ To the signal Y as a YUV signal ₁ U ₁ V ₁ And the chroma decoder 13B outputs the luminance signal Y ₂ And color signal C ₂ To the signal Y as a YUV signal ₂ U ₂ V ₂ And output.
[0021]
The multi-screen processing unit 14 receives the YUV signals from the chroma decoders 13A and 13B (here, the signal Y as the YUV signal). ₁ U ₁ V ₁ , And signal Y ₂ U ₂ V ₂ ), And a signal Y as a YUV signal for simultaneously displaying a plurality of reduced images on one screen based on the obtained YUV signal. _IN , U _IN , V _IN Is generated and output. For example, when the tuner 11A sequentially receives television signals of channels 1 to 5 in a time-division manner, and the tuner 11B receives television signals of channels 6 to 9 in a time-division manner (that is, sequentially receives channels 6 to 9). , The multi-screen processing unit 14 obtains the YUV signals (signals Y) of the acquired nine channels (the nine channels received in ₁ U ₁ V ₁ , And signal Y ₂ U ₂ V ₂ ), A signal Y as a YUV signal for simultaneously displaying nine reduced images (hereinafter, referred to as a multi-image) on one screen. _IN , U _IN , V _IN (For each frame) (signal Y as a YUV signal) ₁ U ₁ V ₁ , And signal Y ₂ U ₂ V ₂ Is generated by synthesizing). That is, the signal Y _IN , U _IN , V _IN Contains signals corresponding to images of nine channels.
[0022]
Further, the multi-screen processing unit 14 outputs the signal Y as a YUV signal to be output. _IN , U _IN , V _IN Generates a DE (Display Enable) signal indicating whether or not it is during the image display period (whether or not the image is a multi-image), and outputs the signal to the switch 54 of the texture emphasizing unit 15.
[0023]
The image data mainly has a structure component constituting an outline of the image and a texture component mainly constituting details thereof. The texture emphasizing unit 15, the delay circuit 16, and the chroma amplifier 17 mainly perform a process related to texture emphasis for emphasizing the texture component (details will be described later). The texture emphasizing unit 15 receives the input luminance signal Y _IN Is subjected to a texture enhancement process, and the luminance signal Y _OUT1 And outputs the result to the chroma amplifier 17.
[0024]
The contour correction circuit 18 has a sharpness function, that is, a function of enhancing the sharpness of the edges and contours of a person or an object in an image (a function of correcting a frequency characteristic). The contour correction circuit 18 outputs the luminance signal Y _OUT1 By correcting the frequency characteristics (contour enhancement correction), the sharpness of the edges and contours of the person or object in the image is corrected. For example, the luminance signal Y _OUT1 If the sharpness of the image signal is abnormally high, the contour correction circuit 18 corrects the frequency characteristic so as to decrease it, and conversely, _OUT1 If the sharpness of is too weak, correction is made to increase the frequency characteristics. In addition, since the parameters of the contour correction circuit 18 can be set by the user, the user can set his or her desired sharpness. The contour correction circuit 18 outputs the luminance signal Y _OUT1 , The frequency characteristic is corrected (contour enhancement correction is performed), and the luminance signal Y _OUT2 Is generated and output to the matrix circuit 19.
[0025]
The delay circuit 16 controls the color difference signal U _IN , V _IN To the luminance signal Y generated in the texture emphasizing unit 15. _OUT1 And output in synchronization. The chroma amplifier 17 receives the color difference signal U _IN , V _IN "Y _IN / Y _OUT1 , And maintain the Y / C ratio (C; both color difference signals U and V) at a constant value before and after the texture enhancement processing. _OUT , V _OUT Generate The generated color difference signal U _OUT , V _OUT Is output to the matrix circuit 19.
[0026]
The YUV signal (digital data) is a set of pixel values corresponding to positions on an image. The luminance signal Y expresses a luminance level, and takes an amplitude value between a white level which is 100% white and a black level which is 100% black. Note that 100% of the white of the image signal is defined as 100 (IRE) in a unit indicating a relative ratio of the image signal called IRE (Institute of Radio Engineers). In the Japanese NTSC signal standard, the white level is 100 IRE and the black level is 0 IRE. Therefore, in the following description, the luminance signal Y takes the minimum value (0IRE) representing black or a value in the vicinity thereof on the “black side”, and the maximum value (100IRE) representing white or a value in the vicinity thereof. This is referred to as “white side”. The color difference signals U and V are respectively converted into a signal "BY" obtained by subtracting the luminance signal Y from blue (B; Blue) and a signal "RY" obtained by subtracting the luminance signal Y from red (R; Red). The colors (hue, saturation, and luminance) are expressed by combining the U signal and the V signal with the luminance signal Y.
[0027]
The matrix circuit 19 outputs a signal Y which is a YUV signal after the texture enhancement processing. _OUT2 , U _OUT , V _OUT Is converted to an RGB signal and output to the driver 20. The driver 20 generates and outputs a drive signal for the display 3 based on the RGB signals. The display 3 displays an image based on a drive signal supplied from the driver 20. The display 3 may be any type of display device, such as a CRT (Cathode Ray Tube) 21, an LCD (Liquid Crystal Display) 22, a PDP (Plasma Display Panel) (not shown), or the like.
[0028]
In the present example, the input image signal is a broadcast signal. However, the present invention is not limited to this, and may be an output signal such as a VCR (Video Cassette Recorder) or a DVD (Digital Versatile Disc).
[0029]
Next, the configuration and function of the texture emphasizing unit 15 of the television receiver 1 will be described in more detail. The texture emphasizing unit 15 includes an S / T (structure / texture) separating circuit 51, a texture amplifying circuit 52, a structure correcting circuit 53, a switch 54, and an adder 55.
[0030]
The texture emphasizing unit 15 performs a process as shown in FIG. That is, the input luminance signal Y _IN Are separated by a S / T separation circuit 51 into a structure component S1 that mainly forms an outline component of the image and a texture component T1 that mainly forms details of the image. The texture component T1 is amplified by the texture amplification circuit 52 to become the texture component T2.
[0031]
The amplitude of the structure component S1 is corrected by the structure correction circuit 53 so that the low-frequency side (black side) is emphasized and the high-frequency side (white side) is suppressed. The structure component S2 and the selected texture component (texture component T1 or T2) are added by the adder 55, and the luminance signal Y _OUT1 It becomes.
[0032]
The switch 54 selects one of the texture component T2 amplified by the texture amplification circuit 52 and the non-amplified texture component T1 based on the DE signal supplied from the multi-screen processing unit 14, and Output to 55. The DE signal is set to DE = 0 when it is in the image display period, and is set to DE = 1 when it is not in the image display period. The switch 54 selects the texture component T2 amplified by the texture amplification circuit 52 when DE = 0 (when the image display period is a multi-image display period) and when DE = 1 ( If it is not the image display period (it is the display period of the multi-image frame), the non-amplified texture component T1 is selected.
[0033]
That is, the DE signal can be understood as a signal indicating that it is a multi-image image signal display period (when DE = 0), and also as a signal indicating that it is a display period of a multi-image frame. (When DE = 1).
[0034]
In the image display period (the multi-image display period), the texture component T2 is superimposed on the corrected structure component S2, and the luminance signal Y _OUT1 Is suppressed. On the other hand, when it is not the image display period (when it is the display period of the frame of the multi-image), the texture component T1 (unamplified texture component) is superimposed on the corrected structure component S2, and the multi-image The amplification of the texture in the frame is suppressed.
[0035]
FIG. 3 is a block diagram showing a configuration of the S / T separation circuit 51. The S / T separation circuit 51 includes a level determination unit 81, a frequency determination unit 82, a filter characteristic determination unit 83, a nonlinear filter 84, and a subtractor 85. The level determining section 81 and the frequency determining section 82 respectively output the luminance signal Y _IN , And a fluctuation range of the frequency, and outputs a determination result to the filter characteristic determination unit 83. The filter characteristic determining unit 83 determines the amplitude level and the frequency threshold of the nonlinear filter 84 according to the determination result. The nonlinear filter 84 uses the filter characteristics determined by the filter characteristic determination unit 83 to generate the luminance signal Y. _IN To extract the structure component S1. The subtractor 85 calculates the original luminance signal Y _IN The texture component T1 is extracted by subtracting the structure component S1 from.
[0036]
The non-linear filter 84 is different from a commonly used linear low-pass filter in that the luminance signal Y _IN Is a non-linear filter that considers both the amplitude level and the frequency of the image, and the structure component S1 constituting the contour of the image is distinguished from the other components. More specifically, the luminance signal Y _IN Among them, the edge component having a sharp amplitude fluctuation is stored as it is, and the small amplitude component other than the edge component is smoothed. As the configuration, for example, the configuration disclosed in JP-A-2001-298621 can be adopted.
[0037]
The non-linear filter 84 is configured as a two-dimensional non-linear filter or a one-dimensional non-linear filter applied to the horizontal direction and the vertical direction of an image, respectively. The pixel values of the peripheral pixels falling within the predetermined threshold ε or less are applied as they are, but if the difference between the absolute values of the pixel values is larger than the threshold ε, it is determined to be an edge, and By using the pixel value of the central pixel, smoothing is performed after eliminating the influence of peripheral pixels.
[0038]
However, in an actual image, a portion where the amplitude variation is large is not always a contour on the image, and conversely, a portion where the amplitude variation is small may be a contour. Therefore, here, the accuracy of the extraction of the structure component S1 is increased by performing smoothing in accordance with not only the amplitude level but also information from the frequency.
[0039]
It is desirable that the non-linear filter 84 obtains a signal with as little change as possible in a portion other than the edge as the structure component S1, but for that purpose, it is necessary to use a filter that can cover a wide range in space. . For example, the luminance signal Y _IN Is a data equivalent to 720 horizontal effective pixels and 288 vertical scanning lines, a filter having a size of about 1/4 (180 pixels × 72 pixels) in both directions may be used.
[0040]
FIG. 4 is a block diagram mainly showing the structure of the structure correction circuit 53 following the S / T separation circuit 51. The texture amplification circuit 52 generates and outputs a texture component T2 by amplifying the texture component T1 input from the S / T separation circuit 51 in accordance with the externally input enhancement gain TE. It is appropriate that the actual value of the enhancement gain TE be a value between 1 and 2. In normal use, the value is, for example, about 1.3 to 1.4, but above this value, the effect of texture emphasis appears strongly. When the value of the enhancement gain TE is set to 2 or more, the texture component is excessively emphasized and gives an uncomfortable feeling.
[0041]
The switch 54 selects and selects one of the texture component T2 amplified by the texture amplification circuit 52 and the non-amplified texture component T1 based on the DE signal supplied from the multi-screen processing unit 14. The texture component is output to the adder 55. As described above, when the DE signal is in the image display period (multi-image image display period), DE = 0. When the DE signal is not in the image display period (multi-image frame display period), DE = 1. Therefore, the switch 54 selects the texture component T2 during the image display period, and selects the texture component T1 during the non-image display period.
[0042]
The structure correction circuit 53 includes a gamma curve generation circuit 101, a gain adjustment circuit 102, a delay circuit 103, and an adder 104. In the structure correction circuit 53, the correction amount of the structure component S1 input from the S / T separation circuit 51 has a positive maximum in an intermediate brightness region excluding the lowest and highest brightness levels of the structure component S1. Such non-linear correction and correction for reducing the maximum value of the luminance level are performed at the same time. In the present embodiment, the non-linear correction is referred to as gamma correction for convenience.
[0043]
As shown in FIG. 5, the gamma curve generation circuit 101 holds a gamma characteristic 101A serving as a reference in advance, and subtracts the structure S1 from the gamma characteristic 101A to obtain a gamma curve γ which is a correction amount of gamma correction. ₀ And outputs it to the gain adjustment circuit 102. The gamma value of the gamma characteristic 101A is, for example, 0.5 to 0.7 (when the input value is X and the output value is Y, the input / output characteristic is Y = X ^0.5 Or Y = X ^0.7 ). Here, the maximum output value of the gamma characteristic 101A is set to be lower than the maximum value of the input structure component S1 by an offset value ΔY so that an output with a reduced white range is obtained.
[0044]
Further, the gamma characteristic 101A has a peak (difference from the input signal, that is, an amplitude output that maximizes the correction amount) P within the range of the input signal level of 20 to 40 (IRE). The black of the outline or shadow of a human face corresponds to approximately 20 to 40 (IRE) in amplitude level. Therefore, by correcting the amplitude level within the range of 20 to 40 (IRE) so as to be raised (emphasized), the emphasis effect on the contours and shadows of the human face is alleviated, and the sense of discomfort for the face is reduced. Can be prevented from occurring. As described above, the feature that the offset value ΔY is relative to the highest value and the peak P is in the range of 20 to 40 (IRE) is that the generated gamma curve γ ₀ Is inherited.
[0045]
The gain adjustment circuit 102 calculates the gamma curve γ ₀ Is configured as an amplifier that adjusts the gain G by adjusting it. FIG. 6 shows the state of the adjustment. Gamma curve γ ₀ Increases the gain G (G> 1), the gamma curve γ ₁ (Gamma curve γ ₀ , The output level increases in the positive or negative direction (absolute value increases), and when the gain G is reduced (0 <G <1), the gamma curve γ ₂ (Gamma curve γ ₀ The output level becomes smaller in the positive or negative direction (absolute value becomes smaller) than in the case of (1). This gives the gamma curve γ ₀ , The degree of bending to the peak P side and the value of the offset value ΔY are simultaneously adjusted. The offset value ΔY is selected, for example, in the range of 2 to 25% of the maximum amplitude value on the input side.
[0046]
The gain adjustment circuit 102 increases or decreases the gain G according to the enhancement gain TE. As the enhancement gain TE increases, the amplitude of the texture component T2 increases. In order to prevent the structure component S2 from being saturated on the black side and the white side with respect to the dynamic range, the characteristics on the black side must be greatly bent in accordance with the enhancement gain TE, and the characteristics on the white side must be kept low. Therefore, in this case, the gain G is adjusted so as to increase, and γ ₁ A gamma curve of the type is obtained. Conversely, when the enhancement gain TE is small, the gain G does not need to be changed much because the amplitude increase of the texture component T2 does not need to be considered so much. Therefore, in this case, the gain G is adjusted to be small in accordance with the degree of amplification, and γ ₂ A gamma curve of the type is obtained.
[0047]
In the present embodiment, the gain adjustment circuit 102 further adjusts the gain G according to the drive gain D. As described above, the driver 20 generates a drive signal having a voltage value according to the luminance gradation. However, in a normal television receiver, the dynamic range of the drive signal is variable, and the brightness of the image is adjusted by offsetting the high-brightness side (white side) of the dynamic range to increase or decrease the effective drive voltage. Is to be adjusted. The gain for this dynamic range is the drive gain D. That is, here, the two factors of the enhancement gain TE and the drive gain D are considered simultaneously and the gamma curve γ ₀ Is determined.
[0048]
A large drive gain D means that the drive is performed at a high pressure. At this time, the white side has a particularly high luminance, so that gradation cannot be obtained due to the characteristics of human eyes. In such a state, no matter how much the texture component is enhanced, an effective image quality improvement cannot be expected. In such a case, if the amplitude of the structure component S2 is reduced to a level at which the gradation can be visually recognized, the emphasized texture component T2 can be sufficiently recognized. Therefore, when the drive gain D is large, the gain G is adjusted to be large. In this case, if the enhancement gain TE is large, the gain G needs to be further increased.
[0049]
Conversely, if the drive gain D becomes small, such a problem does not occur, so that it is not necessary to correct the structure component S2, and the gain G is selected to be small. However, if the enhancement gain TE is also small, the gain G may be kept small, but if the enhancement gain TE is large, the gain G needs to be increased according to the enhancement gain TE.
[0050]
Although the drive gain D is continuously variable, it is generally set to several levels in advance corresponding to the image quality mode, and one of them is selected from outside. As a specific example, a dynamic mode (D = 100%), a standard mode (D = 80 to 90%), a soft mode (D = 50%), and the like are set. In the dynamic mode or the standard mode, the display 3 including the CRT 21 or the LCD 22 is driven at a voltage of 100% to 80% of the full range. As described above, the brightness becomes higher as the drive is performed near the upper limit of the drive level. However, the brightness visually recognized on the display 3 becomes saturated on the white side, and the gray level on the white side cannot be obtained much. On the other hand, in the soft mode, since the full range is driven by the voltage of 50% of that in the dynamic mode, the luminance is slightly lowered, but a proper gradation expression is performed. Therefore, in an image quality mode in which the drive gain D is large, such as the dynamic mode and the standard mode, it is necessary to lower the white level of the finally obtained luminance signal in order to secure the characteristics on the high luminance side. Therefore, by increasing the gain G, the gamma curve γ ₀ Is set to be large.
[0051]
It is preferable that the gain G be selected so that the amplitude of the drive signal in the driver 20 finally fills the dynamic range. However, when the display 3 is the CRT 21, the high-frequency component of the luminance of the image displayed on the display screen tends to decrease significantly on the high luminance side, so that the amplitude level of the drive signal is limited to just the dynamic range. Instead, the gain G is adjusted so as to further lower it. As described above, the gain G is also adjusted according to the type of the display 3. For example, when the enhancement gain TE is 1.7, the gain G is around 95% when the display 3 is the LCD 22, and around 90% when the display 3 is the CRT 21. It is said.
[0052]
In the gain adjusting circuit 102, the gamma curve γ is obtained by the gain G obtained as described above. ₀ Is adjusted.
[0053]
The delay circuit 103 delays the input structure component S1 and generates a gamma curve γ by the gamma curve generation circuit 101 and the gain adjustment circuit 102. ₀ Is output in synchronization with the correction component based on. The adder 104 receives the input structure component S1 and the gamma curve γ ₀ , And a structure component S2 is generated and output.
[0054]
The structure component S2 is further added to the texture component (texture component T1 or texture component T2) by the adder 55. As a result, the texture component is emphasized during the image display period, and the luminance signal Y in which the structure component is corrected is provided. _OUT1 Is generated and the image is not in the image display period, the texture component is not emphasized, and only the structure component is corrected. _OUT1 Is generated.
[0055]
Next, an image display process in the television receiver 1 will be described with reference to flowcharts in FIGS. This process is started when an image signal is input to the Y / C separation circuits 12A and 12B of the television receiver 1 in FIG.
[0056]
In step S1, the Y / C separation circuits 12A and 12B each obtain an image signal and convert the corresponding image signal into a luminance signal Y. ₁ And color signal C ₁ , And the luminance signal Y ₂ And color signal C ₂ , Respectively. Specifically, since the television signal received and demodulated by the tuner 11A is input to the Y / C separation circuit 12A as a composite signal, the Y / C separation circuit 12A outputs the composite signal ( Image signal) to the luminance signal Y ₁ And color signal C ₁ And outputs it to the chroma decoder 13A. Also, the television signal received and demodulated by the tuner 11B is input to the Y / C separation circuit 12B as a composite signal, so that the Y / C separation circuit 12B receives the input composite signal (image signal). With the luminance signal Y ₂ And color signal C ₂ And outputs it to the chroma decoder 13B.
[0057]
For example, the tuner 11A receives television signals of five programs on channels 1 to 5 in a time division manner, and the tuner 11B receives television signals of four programs on channels 6 to 9 in a time division manner. Therefore, the luminance signal Y ₁ , Color signal C ₁ Contains sequentially television signals corresponding to five programs, and a luminance signal Y ₂ , Color signal C ₂ Contains television signals corresponding to four programs in sequence.
[0058]
In step S2, the chroma decoders 13A and 13B output the corresponding luminance signal and color signal (the chroma decoder 13A outputs the luminance signal Y). ₁ And color signal C ₁ , The chroma decoder 13B outputs the luminance signal Y ₂ And color signal C ₂ ) Is decoded, and the YUV signal (the chroma decoder 13A outputs the signal Y ₁ U ₁ V ₁ , The chroma decoder 13B outputs the signal Y ₂ U ₂ V ₂ ). The chroma decoders 13A and 13B output the generated YUV signal (the chroma decoder 13A outputs the signal Y). ₁ U ₁ V ₁ , The chroma decoder 13B outputs the signal Y ₂ U ₂ V ₂ ) Are supplied to the multi-screen processing unit 14.
[0059]
The multi-screen processing unit 14 receives a signal Y as a YUV signal from the chroma decoder 13A. ₁ U ₁ V ₁ Is supplied from the chroma decoder 13B to the signal Y as a YUV signal. ₂ U ₂ V ₂ Is supplied. In the case of the present example, the chroma decoder 13A supplies YUV signals corresponding to five programs, and the chroma decoder 13B supplies YUV signals corresponding to four programs. YUV signals corresponding to nine programs are acquired.
[0060]
Therefore, in step S3, the multi-screen processing unit 14 outputs the signal Y as the supplied YUV signal. ₁ U ₁ V ₁ And signal Y ₂ U ₂ V ₂ In the case of the present example, the signal Y is used as a YUV signal for performing multi-screen display based on YUV signals corresponding to nine programs. _IN U _IN V _IN Generate Specifically, an image (multi-image) in which the size of the image of each channel is reduced to about 1/3 in the vertical direction and the horizontal direction is generated, and is arranged on a 3 × 3 matrix in one frame. Signal Y _IN U _IN V _IN Generate Generated signal Y _IN U _IN V _IN Of the luminance signal Y _IN Is output to the texture emphasizing unit 15 and the chroma amplifier 17 and the color difference signal U _IN , V _IN Is input to the delay circuit 16.
[0061]
In step S4, the texture emphasizing unit 15 performs a texture emphasizing process. Specifically, the luminance signal Y _IN Is separated into a structure component S1 and a texture component T1, the texture component T1 is amplified to generate a texture component T2, and the structure component S1 is corrected to generate a structure component S2. The switch 54 selects one of the amplified texture component T2 and the non-amplified texture component T1, and outputs the selected texture component to the adder 55. The adder 55 adds the texture component supplied from the switch 54 and the corrected structure component S2, and generates a luminance signal Y _OUT1 Is generated (see FIG. 2). Details of the processing will be described later with reference to FIGS. The texture emphasizing unit 15 generates the luminance signal Y _OUT1 Is supplied to the contour correction circuit 18 and to the chroma amplifier 17.
[0062]
In step S5, the contour correction circuit 18 outputs the luminance signal Y _OUT1 Is corrected (the luminance signal Y _OUT1 Is corrected), and the luminance signal Y _OUT2 Generate
[0063]
In step S6, the delay circuit 16 outputs the color difference signal U supplied by the multi-screen _IN , V _IN Delay. Specifically, the delay circuit 16 controls the luminance signal Y generated in the texture emphasizing unit 15. _OUT1 And the color difference signal U _IN , V _IN Delay. The delay circuit 16 outputs the delayed color difference signal U _IN , V _IN Is supplied to the chroma amplifier 17.
[0064]
In step S7, the chroma amplifier 17 outputs the luminance signal Y supplied from the multi-screen processing unit 14 by the processing in step S3. _IN (The luminance signal before the texture enhancement processing) and the luminance signal Y supplied by the processing in step S4. _OUT1 (Luminance signal after texture emphasis processing) ratio “(Y _IN / Y _OUT1 )] And obtain the color difference signal U _IN , V _IN To the color difference signal U _IN , V _IN Is the luminance signal Y _OUT Amplify by the amount of amplification. Thereby, the color difference signal U is maintained such that the Y / C ratio is kept constant before and after the texture enhancement processing. _OUT , V _OUT Is generated. The chroma amplifier 17 generates the color difference signal U _OUT , V _OUT Is supplied to the matrix circuit 19.
[0065]
In step S8, the matrix circuit 19 outputs the luminance signal Y from the contour correction circuit 18. _OUT2 (The luminance signal Y generated by the process of step S5 _OUT2 ) Is obtained, and the color difference signal U is _OUT , V _OUT (The color difference signal U generated by the process of step S7 _OUT , V _OUT ), And the signal Y as this YUV signal is obtained. _OUT2 U _OUT V _OUT Is converted to an RGB signal. That is, an RGB signal is generated from the YUV signal after the texture enhancement processing. The matrix circuit 19 outputs the converted RGB signals to the driver 20.
[0066]
In step S9, the driver 20 generates a drive signal based on the RGB signals and outputs the drive signal to the display 3. Specifically, the driver 20 amplifies the input RGB signal (the RGB signal converted by the matrix circuit 19 by the process of step S8), generates a drive signal having a voltage value corresponding to the luminance gradation, and generates a display signal. Output to 3.
[0067]
In step S10, the display 3 displays an image based on the input drive signal. For example, when the CRT 21 is selected as the display 3, the CRT 21 displays an image based on the drive signal.
[0068]
Next, the texture enhancement processing in the texture enhancement unit 15 will be described with reference to the flowchart in FIG. This flowchart explains the processing of step S4 in FIG. 7 in detail. This processing is performed by the multi-screen processing unit 14 using the luminance signal Y. _IN Is supplied to the S / T separation circuit 51.
[0069]
In step S51, the S / T separation circuit 51 performs an S / T separation process. Specifically, the luminance signal Y _IN , The characteristic of the filter is determined based on the fluctuation range of the amplitude level and the fluctuation range of the frequency. _IN Is smoothed, so that the structure component S1 is obtained and the texture component T1 is obtained (FIG. 2). Details of the processing will be described later with reference to FIG. The S / T separation circuit 51 supplies the generated texture component T1 to the texture amplification circuit 52, and supplies the structure component S2 to the structure correction circuit 53.
[0070]
In step S52, the texture amplification circuit 52 performs a texture amplification process. Specifically, the texture component T1 is amplified based on the enhancement gain TE to generate the texture component T2 (FIG. 2). The texture amplification circuit 52 outputs the generated (amplified) texture component T2 to the switch 54. The switch 54 selects one of the amplified texture component T2 and the non-amplified texture component T1, and outputs the selected texture component to the adder 55. The details of this processing will be described later with reference to FIG.
[0071]
In step S53, the structure correction circuit 53 performs a structure correction process. Specifically, while delaying the structure component S1, the gamma curve γ ₀ Gamma curve γ ₀ And the gamma curve γ ₀ Are added to generate a structure component S2 (FIG. 2). Details of the processing will be described later with reference to FIG. The structure correction circuit 53 outputs the generated structure component S2 to the adder 55.
[0072]
In step S54, the adder 55 adds the structure component S2 corrected by the processing in step S53 and the texture component (texture component T1 or texture component T2) selected by the switch 54 in the processing in step S52, and outputs a luminance signal. Y _OUT1 Is generated (FIG. 2). Generated luminance signal Y _OUT1 Is supplied to the matrix circuit 19 and also to the chroma amplifier 17. By this processing, the texture component is emphasized.
[0073]
The luminance signal Y subjected to the texture enhancement processing by the processing of FIG. _OUT1 As described above, the processing of steps S5 to S10 in FIG. 7 is further executed based on
[0074]
FIG. 9 is a flowchart illustrating the S / T separation processing in the S / T separation circuit 51 in step S51 in FIG. This processing is performed by the S / T separation circuit 51 (the level determination unit 81, the frequency determination unit 82, and the nonlinear filter 84 of the texture amplification circuit 52) shown in FIG. _IN Is started when is supplied.
[0075]
In step S101, the level determination unit 81 determines whether the luminance signal Y _IN Is determined, and the result of the determination is output to the filter characteristic determining unit 83.
[0076]
In step S102, the frequency determination unit 82 sets the luminance signal Y _IN Is determined, and the result of the determination is output to the filter characteristic determining unit 83.
[0077]
In step S103, the filter characteristic determination unit 83 determines the amplitude level of the nonlinear filter 84 based on the determination result by the level determination unit 81 (processing in step S101) and the determination result by the frequency determination unit 82 (processing in step S102). And a frequency threshold. The determined amplitude level and frequency threshold are output to the nonlinear filter 84.
[0078]
In step S104, the non-linear filter 84 obtains the amplitude level and the frequency threshold from the filter characteristic determination unit 83, and based on the threshold, _IN , And extracts a structure component S1 (FIG. 2). The extracted structure component S1 is image data in which an edge portion is stored as it is and only the other portion is smoothed. That is, it is data representing a rough configuration such as a contour line in an image. For example, as shown in FIG. 12 (a diagram for explaining the structure component and the texture component in principle), the signal Y as the input YUV signal is used. _IN U _IN V _IN Is an image 121, an image generated by the extracted structure component S1 (mainly, a component constituting a contour component of the image) is an image 122.
[0079]
In step S105, the subtractor 85 outputs the luminance signal Y _IN Is subtracted from the structure component S1. Thus, the texture component S1 is extracted (FIG. 2). The extracted texture component T1 is a small-amplitude component obtained by removing the structure component S1 from the original signal, and is data corresponding to details in an image, for example, fine undulations such as clothing patterns. In the case of the example of FIG. 12, an image generated by the extracted texture component S1 (mainly, a component constituting details of the image) is an image 123. As described above, the image signal is separated into the structure component S1 (the component corresponding to the image 122) and the texture component T1 (the component corresponding to the image 123).
[0080]
By the processing of FIG. 9, the structure component S1 and the texture component T1 are generated and output from the S / T separation circuit 51. As described above, the processing of step S52 of FIG. 8 is executed based on the texture component T1 separated by the processing of FIG. 9, and the processing of step S53 of FIG. 8 is executed based on the structure component S1.
[0081]
FIG. 10 is a flowchart illustrating the texture amplification processing in the texture amplification circuit 52 and the switch 54 (the texture amplification circuit 52 and the switch 54 in FIG. 4) in step S52 in FIG. This processing is started when the texture component T1 is supplied from the S / T separation circuit 51.
[0082]
In step S151, the texture amplification circuit 52 acquires the texture component T1 from the subtractor 85 of the S / T separation circuit 51 (see FIG. 2).
[0083]
In step S152, the texture amplification circuit 52 amplifies the acquired texture component T1 based on the externally input enhancement gain TE to generate the texture component T2 (see FIG. 2).
[0084]
In step S153, the texture amplification circuit 52 outputs the generated texture component T2 to the adder 55.
[0085]
In step S154, the switch 54 acquires a DE signal from the multi-screen processing unit 14. The multi-screen processing unit 14 outputs DE = 0 when the currently supplied YUV signal is in the image display period. In the case of the display period), DE = 1 is output.
[0086]
Specifically, as shown in FIG. 13, when displaying an entire image 200 including a plurality of reduced images (multi-images) 201 to 209 on one screen, in a range inside the multi-images 201 to 209, DE = 0, and in a range other than the multi images 201 to 209, DE = 1. In the case of the present example, the television signals of the programs corresponding to the multi-images 201 to 205 are received by the tuner 11A, and the television signals of the programs corresponding to the multi-images 206 to 209 are received by the tuner 11B. Things. That is, the multi images 201 to 205 correspond to channels 1 to 5 of the program received by the tuner 11A, and the multi images 206 to 209 correspond to channels 6 to 9 of the program received by the tuner 11B.
[0087]
In step S155, the switch 54 determines whether or not the DE signal supplied from the multi-screen processing unit 14 is DE = 0 (during an image display period). If it is determined that DE = 0, the process proceeds to step S156, and the switch 54 acquires the texture component T2 (the texture component T2 generated in the process of step S153) from the texture amplification circuit 52.
[0088]
If it is determined in step S155 that DE = 0 is not satisfied, that is, if it is determined that DE = 1 (it is a multi-image frame), the process proceeds to step S157, where the switch 54 sets the S / T separation circuit 51 to ON. , The texture component T1 is obtained.
[0089]
After the processing in step S156 or after the processing in step S157, in step S158, the switch 54 outputs the acquired texture component to the adder 55. That is, when the switch 54 selects the texture component T2 in step S156, the texture component T2 is output to the adder 55, and when the switch 54 selects the texture component T1 in step S157, the texture component T1 is added to the adder 55. Output to
[0090]
When the entire image 200 as shown in FIG. 13 is displayed by the processing of FIG. 10, portions other than the multi images 201 to 209 which are the reduced images and which are the entire image 200 (that is, the multi image ) Can be reliably identified, so that the contrast enhancement (unnecessary enhancement) of the frame region of the multi-image can be prevented.
[0091]
Specifically, even when the width of the frame between each multi-image is narrow (for example, when the interval between the multi-image 201 and the multi-image 204 is narrow), the switch 54 is in the image display period (DE = 0). Since the texture component is selected by distinguishing between the case and the case (DE = 1), unnecessary enhancement of the contrast of the frame region can be suppressed as a result. Thereby, for example, the image around the frame (for example, near the edge of the multi-image 20i (i = 1, 2, 3,..., 9)) and the multi-image 20i (i = 1, 2, 3,. When the luminance difference from the frame of (9) is large, it is possible to determine that the frame of the multi-image is a texture component and prevent the luminance difference from being emphasized.
[0092]
Further, since each of the multi images 201 to 209 is regarded as one image and can be arbitrarily separated into a structure component and a texture component to enhance the texture component, the contrast of each original multi image can be easily determined. Adjustments can be made.
[0093]
Based on the texture component (texture component T1 or texture component T2) generated by the process of FIG. 10, as described above, the process of step S54 of FIG. 8 is further performed.
[0094]
FIG. 11 is a flowchart for explaining the structure correction processing in the structure correction circuit 53 in step S53 of FIG. This process is started when the structure component S1 is supplied from the S / T separation circuit 51 to the structure correction circuit 53 of FIG. 4 (the gamma curve generation circuit 101 of the structure correction circuit 53 and the delay circuit 103).
[0095]
In step S201, the delay circuit 103 acquires the structure component S1 and delays it. Specifically, the gamma curve γ generated in the gain adjustment circuit 102 ₀ And outputs the delayed structure component S1 to the adder 104.
[0096]
In step S202, the gamma curve generation circuit 101 subtracts the structure component S1 from the gamma characteristic 101A to obtain a gamma curve γ that is a correction amount of the gamma correction. ₀ And outputs it to the gain adjustment circuit 102 (FIG. 5). In the case of the present example, the gamma curve γ ₀ Has the following three features. First, a curve is formed such that the black side rises when a gamma value is selected. Second, the input signal has a curve peak P in the range of 20 to 40 (IRE). Third, the highest output value is set lower than the highest input value by an offset value ΔY. The gamma curve generation circuit 101 generates the gamma curve γ ₀ Is output to the gain adjustment circuit 102.
[0097]
In step S203, the gain adjustment circuit 102 sets the input gamma curve γ ₀ The gain (gain G) is adjusted (FIGS. 4 and 6). Specifically, the enhancement gain TE and the drive gain D are input to the gain adjustment circuit 102, and the gain G is adjusted depending on the balance between the two. As a result, the gain G is a value that takes into account the degree of amplification of the texture component T1, the signal control on the driver 20 side, and conditions relating to image quality such as the characteristics of the display 3 itself. With this gain G, the gamma curve γ ₀ Is a characteristic of the luminance signal Y after synthesis. _OUT1 Is set to fall within the dynamic range. Here, the luminance signal Y _OUT1 The gain G is adjusted so that the amplitude range of the dynamic range falls within the dynamic range, and the gamma curve γ ₀ Shall be adjusted. Gamma curve γ with this gain G adjusted ₀ Is output to the adder 104.
[0098]
In step S204, the adder 104 sets the gamma curve γ ₀ (The gamma curve with the gain G adjusted by the processing in step S203) and the gamma curve γ by the delay circuit 103. ₀ Is obtained, and a gamma curve γ is added to the structure component S1. ₀ Is added. This is equivalent to performing gamma correction. In this gamma correction, not only the contrast is corrected by amplifying the amplitude level on the black side to rise, but also the amplitude level on the white side is reduced by the offset ΔY. Further, a correction is made such that a luminance region within a range of 20 to 40 (IRE) has a peak and the amplitude is raised. As described above, the gamma curve γ described above is added to the structure component S1. ₀ And the structure component S2 is generated (FIG. 2).
[0099]
In step S205, the adder 104 outputs the generated structure component S2 to the adder 55.
[0100]
As described above, the structure component S2 generated by the processing of FIG. 11 is further subjected to the processing of step S54 of FIG.
[0101]
The processing of FIGS. 7 to 11 is summarized as follows. In step S155 of FIG. 10, the switch 54 distinguishes between the case where the image display period is set (DE = 0) and the case where the image display period is not set (DE = 1), and the amplified texture component T2 and the amplified texture component T2. One of the non-existing texture components T1 is selected, and in step S54 of FIG. 8, the adder 55 adds the structure component S2 and the selected texture component to generate a luminance signal Y. _OUT1 Generate
[0102]
In the image display period (DE = 0), since the structure component S2 has its black side raised by gamma correction with reference to the enhancement gain TE and the drive gain D (the process of FIG. 11), the texture component T2 is added. The later minimum amplitude level fills the dynamic range. Further, since the white-side amplitude level is reduced with reference to the enhancement gain TE and the drive gain D (the processing in FIG. 11), the maximum amplitude level after adding the texture component T2 becomes full of the dynamic range. Therefore, the luminance signal Y _OUT1 Are designed to fall within the dynamic range of the drive signal of the driver 20 at the same time that the texture emphasis processing is performed.
[0103]
That is, the luminance signal Y which is the original signal _OUT1 As a result, the drive signal falls within the dynamic range on both the white side and the black side. Therefore, the phenomenon of black jam or white jam is prevented. Moreover, here, the drive signal is driven to the full dynamic range, thereby preventing the image from becoming darker than necessary. Note that, as described above, the luminance signal Y _OUT1 In, the structure component correction is performed in consideration of the signal control on the driver 20 side and the conditions related to the image quality such as the characteristics of the display 3 itself, so that the driving signal based on this is displayed with an appropriate contrast distribution. It has become.
[0104]
Also, the luminance signal Y _OUT1 Has been corrected so as to increase the amplitude of the low-luminance region so as to have a peak within the range of 20 to 40 (IRE). Therefore, even in a drive signal based on this, the amplitude of the luminance region is raised. It becomes. Therefore, the black color corresponding to the outline or shadow of the person's face is corrected to be bright, and the effect of the texture component amplification in this range is reduced.
[0105]
Therefore, in the image displayed on the display 3, the phenomenon of blackening or whitening is prevented, and the effect of the texture emphasis processing, that is, the effect of giving a natural impression despite sharpness due to the improvement of the contrast of details is regretted. It is demonstrated without. Further, since the overall contrast balance is adjusted by the correction of the structure component, the contrast enhancement of the details can be clearly recognized even in a bright portion, and the texture enhancement becomes more effective. Further, the contour and shadow of the person's face are alleviated from being emphasized black by the texture emphasizing process, so that the image quality can be prevented from being degraded. Further, the image quality can be further adjusted to the image quality after the contour correction.
[0106]
When the image display period is not reached (DE = 1), unnecessary emphasis of the texture component can be prevented.
[0107]
By the above processing, the range of the multi images 201 to 209 and the range that is not the multi image can be reliably identified, so that unnecessary enhancement of the contrast of the frame region of the multi image can be prevented.
[0108]
Specifically, even when the width of the frame between the images is narrow (for example, when the interval between the multi-image 201 and the multi-image 204 is narrow), when the switch 54 is in the image display period (DE = 0), Since the texture component is selected by discriminating the case where there is no (DE = 1), as a result, unnecessary enhancement of the contrast of the frame region can be suppressed. Thereby, for example, the image around the frame (for example, near the edge of the multi-image 20i (i = 1, 2, 3,..., 9)) and the multi-image 20i (i = 1, 2, 3,. When the luminance difference from the frame of (9) is large, it is possible to determine that the frame of the multi-image is a texture component and prevent the luminance difference from being emphasized.
[0109]
In addition, since each of the multi images 201 to 209 is regarded as one image and can be arbitrarily separated into a structure component and a texture component and the texture component can be emphasized, the contrast of each multi image can be easily adjusted. Can do it.
[0110]
Further, when displaying the entire image 200 including the plurality of multi images 201 to 209, the contrast can be easily and quickly adjusted for each multi image.
[0111]
Note that a television receiver having a multi-screen display function of simultaneously displaying a plurality of multi-images (reduced images) on one screen can also be configured as follows.
[0112]
FIG. 14 is a block diagram illustrating a configuration example of another television receiver 400 to which the present invention has been applied. In the figure, the parts corresponding to those in FIG.
[0113]
In the case of the example of FIG. 14, the television receiver 400 is provided with a DE area conversion unit 411, and the DE area conversion unit 411 receives the DE signal supplied from the multi-screen processing unit 14 (see FIG. Similarly, the output YUV signal (signal Y _IN U _IN V _IN ) Generates a frame signal DE ′ so that an area of a non-image display period (a DE signal indicating that the frame is a multi-image frame) is further expanded two-dimensionally (in the horizontal and vertical directions). Specifically, as shown in FIG. 15, the DE signal is changed to the DE ′ signal so that the area of the frame of the multi-image is expanded (so that a part of the multi-image becomes a frame).
[0114]
In FIG. 15, the multi-image 20i (i = 1, 2, 3,..., 9) is narrowed in the horizontal direction by x pixels from the left or right end (the frame is expanded), and Inward from the upper or lower end, the pixel is narrowed (the frame is expanded) by y pixels (lines) in the vertical direction. That is, in a predetermined range near the edge of the multi-image, the display area of the multi-image is set as a frame of the multi-image by the DE area conversion unit 411. As a result, in the region of the image 50i (i = 1, 2,..., 9), the DE region conversion unit 411 outputs a signal DE ′ = 0 indicating the image display period, and outputs the image 50i (i = 1, 2). In areas other than (2, 3,..., 9), a signal indicating that it is not an image display period (that is, a frame signal indicating that it is a multi-image frame area) DE ′ = 1 is output.
[0115]
The switch 412 acquires the DE ′ signal from the DE area conversion unit 411, and based on the DE ′ signal, the texture component T2 (the component obtained by amplifying the texture component T1) generated by the texture amplification circuit 52 and the amplified signal. One of the non-existing texture components T1 (texture component T1 output from the S / T separation circuit 51) is selected.
[0116]
Specifically, when the currently output YUV signal is in the image display period (in the range of the multi-image 20i), the multi-screen processing unit 14 supplies DE = 0 to the DE area conversion unit 411, and outputs the YUV signal. Is not in the image display period (in the case of a frame area outside the area of the multi-image 20i), DE = 1 is supplied to the DE area conversion unit 411. Even in the image display period (when DE = 0), the DE area conversion unit 411 sets a horizontal direction from the left and right edges of the multi image 20i (i = 1, 2, 3,..., 9). The signal is set to DE ′ = 1 so that the region inside only x pixels and the region inside only y pixels (lines) in the vertical direction from the upper and lower edges also become the frame region, and the signal is set in other ranges (for example, The DE signal inside the image 501 or outside the multi-image 201 is set as it is as DE ′ (that is, DE ′ = DE).
[0117]
The switch 412 acquires the texture component T2 from the texture amplification circuit 52 when the DE ′ signal from the DE area conversion unit 411 is set to DE ′ = 0, and performs S / T separation when the DE ′ signal is set to DE ′ = 1. The texture component T1 (that is, the non-amplified texture component T1) is obtained from the circuit 51.
[0118]
Next, the texture enhancement processing in the texture enhancement unit 410 of the television receiver 400 in FIG. 14 will be described with reference to the flowchart in FIG. The flowchart of FIG. 16 corresponds to the processing of the flowchart of FIG. 10 among the above-described FIGS. 7 to 11, and the other processing (the processing of FIGS. 7, 8, 9, and 11) is the same as that of FIG. 7, FIG. 8, FIG. 9, and FIG. 11, and the description thereof is omitted. That is, the flowchart in FIG. 16 is a detailed description of the process in step S52 in FIG. 8, and corresponds to the flowchart in FIG. Steps S301 to S303 in FIG. 16 correspond to steps S151 to S153 in FIG. 10, respectively, and steps S310 to S313 in FIG. 16 correspond to steps S155 to S158 in FIG. 10, respectively. .
[0119]
In step S301, the texture amplification circuit 52 acquires the texture component T1 from the subtractor 85 of the S / T separation circuit 51 (processing corresponding to step S151 in FIG. 10).
[0120]
In step S302, the texture amplification circuit 52 amplifies the acquired texture component T1 based on the enhancement gain TE input from the outside, and generates a texture component T2 (processing corresponding to step S152 in FIG. 10).
[0121]
In step S303, the texture amplification circuit 52 outputs the generated texture component T2 to the switch 412 (processing corresponding to step S153 in FIG. 10).
[0122]
In step S304, the DE area conversion unit 411 acquires a DE signal from the multi-screen processing unit 14. As described above, the DE signal is set to DE = 0 when the currently supplied YUV signal is in the image display period, and is set to DE = 1 in the non-image display period (when the frame is a multi-image frame). ing.
[0123]
In step S305, the DE area conversion unit 411 determines whether DE = 1 (whether the frame is a multi-image frame). If it is determined that DE = 1 is not satisfied (that is, DE = 0), in step S306, the DE area conversion unit 411 determines whether the area corresponding to the YUV signal currently being processed is to be a frame area. Is determined.
[0124]
More specifically, the DE area conversion unit 411 determines whether the location corresponding to the YUV signal currently being processed is inside any of the images 501 to 509 in FIG. If it is determined to be inside any one of the above, it is determined in the processing of step S306 that it is not a frame area. Conversely, when the DE area conversion unit 411 determines that the image is inside the multi-images 201 to 209 and outside the images 501 to 509, it is determined in step S306 that the image is a frame area. Note that this processing is processing after it is determined in step S305 that DE = 1 is not satisfied (that is, DE = 0), and therefore, of course, the multi-image 20i (i = 1, 2, 3,...)・, 9) It is not outside.
[0125]
If it is determined in step S306 that the image is not a frame area (that is, it is inside any of the images 501 to 509), in step S307, the DE area conversion unit 411 outputs DE ′ = 0.
[0126]
If it is determined in step S305 that DE = 1, or if it is determined in step S306 that it is a frame area, the process proceeds to step S308, in which the DE area conversion unit 411 determines that DE ′ = 1 (multi-image (A signal indicating that the frame is in the display period).
[0127]
In step S309, the switch 412 acquires DE ′ from the DE area conversion unit 411 (a process corresponding to step S154 in FIG. 10). This DE 'has a value of 0 or 1.
[0128]
In step S310, the switch 412 determines whether or not the DE ′ signal is DE ′ = 0 (not in the frame area, that is, inside any of the images 501 to 509) (step S155 in FIG. 10). Processing corresponding to). If it is determined that DE ′ = 0, the process proceeds to step S311, and the switch 412 acquires the texture component T2 (the texture component T2 generated in the process of step S303) from the texture amplification circuit 52 (FIG. 10). Corresponding to step S156).
[0129]
If it is determined in step S310 that DE ′ = 0 is not satisfied, that is, if it is determined that DE ′ = 1 (not during the image display period), the process proceeds to step S312, where the switch 412 sets the S / T separation circuit 51. , A texture component T1 (texture component T1 that has not been amplified) is obtained from (step S157 in FIG. 10).
[0130]
After step S311 or after step S312, in step S313, the switch 412 outputs the obtained texture component (texture component T1 or texture component T2) to the adder 55. For example, when the switch 412 acquires the texture component T2 in step S311, the switch 412 outputs the texture component T2 to the adder 55. When the switch 412 acquires the texture component T1 in step S312, it outputs this to the adder 55.
[0131]
When displaying the entire image 200 including a plurality of multi-images 201 to 209 as shown in FIG. 15 by the processing in FIG. 16, the frame area of each multi-image is further enlarged (a predetermined area near the edge of the multi-image is determined). , The frame of the multi image is further widened), and contrast enhancement (adjustment) in the frame area and a predetermined range near the edges of the multi images 201 to 209 is prevented. The frame (edge) can be prevented from being abnormally emphasized.
[0132]
As a result, when displaying multiple screens, contrast enhancement can be realized without any adverse effect.
[0133]
When the luminance difference between the image and the frame in a predetermined range near the edge of the multi-image 20i (i = 1, 2, 3,..., 9) is large, the predetermined range near the frame and the edge is large. Since the texture component T1 of the image is not amplified, enhancement of the luminance difference between the image and the frame can be prevented.
[0134]
Further, when displaying an entire image including a plurality of multi-images, the contrast can be easily and quickly adjusted for each multi-image.
[0135]
As described above, the television receiver separates the image signal into the texture component and the structure component and emphasizes the texture component. Therefore, when displaying a plurality of multi-images on one screen (when performing multi-screen display). Also, the contrast can be easily enhanced (adjusted) for each multi image.
[0136]
In addition, since the texture enhancement is adjusted based on the signal indicating the frame area range (the signal indicating the image display period), when a plurality of multi-images are simultaneously displayed on one screen, Even when the interval (frame of the multi-image) is narrow, it is possible to prevent the frame between the multi-images from being determined as a texture component, thereby preventing the luminance difference between the frame and the multi-image from being emphasized. Can be.
[0137]
Further, when displaying a plurality of multi-images on one screen, the contrast of each multi-image is adjusted, and the luminance difference between the frame and each multi-image is prevented from being emphasized. it can.
[0138]
Further, since the frame signal indicating the frame of the multi-image is generated based on the signal indicating the image display period, it can be easily realized.
[0139]
Furthermore, since the frame area is set (DE ') even in an area wider than the frame area of the multi image (a predetermined range near the edge of the multi image), the edge of each multi image is abnormally emphasized. Can be prevented.
[0140]
The present invention is not limited to a television receiver having a multi-screen display function, but may be applied to a television receiver that performs a multi-channel index display such that the content of each broadcast program channel is displayed as a still image. Can be.
[0141]
Further, the multi-image does not necessarily need to be an image whose size is reduced. Originally, the image may be smaller in size than the standard size image.
[0142]
Further, in the above example, the gamma curve γ ₀ Is adjusted by combining the two conditions of the enhancement gain TE and the drive gain D, but may be adjusted with reference to only the enhancement gain TE.
[0143]
In the above example, the television receiver has been described. However, the present invention is not limited to a television receiver having an image display function, and may be a television camera, a digital camera, a VTR (Video Tape Recorder), a printer, a personal computer, or the like. The present invention can be applied to all apparatuses that perform image processing.
[0144]
Further, in the above-described embodiment, each operation of S / T classification, texture enhancement, and structure correction according to the image processing method of the present invention is performed by a circuit, but these operations may be realized by software. Good.
[0145]
Note that, in this specification, the steps describing each flowchart include, in addition to the processing performed in chronological order according to the described order, not only the processing performed in chronological order but also the processing performed in parallel or individually. Is also included.
[0146]
【The invention's effect】
As described above, according to the present invention, the contrast of an image can be adjusted. In particular, according to the present invention, when displaying a plurality of multi images on one screen, the contrast can be adjusted for each multi image. Further, the contrast can be easily and quickly adjusted for each multi image.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of a television receiver to which the present invention has been applied.
FIG. 2 is a diagram illustrating an operation of a texture emphasizing unit in FIG. 1;
FIG. 3 is a block diagram illustrating a configuration example of an S / T separation circuit in FIG. 1;
FIG. 4 is a block diagram illustrating a configuration example of a structure correction circuit and a texture amplification circuit of FIG. 1;
FIG. 5 is a diagram illustrating the operation of the gamma curve generation circuit of FIG.
FIG. 6 is a diagram illustrating the operation of the gain adjustment circuit of FIG. 4;
FIG. 7 is a flowchart illustrating image display processing in the television receiver in FIG. 1;
FIG. 8 is a flowchart illustrating a texture emphasizing process in step S4 of FIG. 7;
FIG. 9 is a flowchart illustrating an S / T separation process in step S51 of FIG. 8;
FIG. 10 is a flowchart illustrating a texture emphasizing process in step S52 of FIG. 8;
FIG. 11 is a flowchart illustrating a structure correction process in step S53 of FIG. 8;
FIG. 12 is a diagram illustrating a structure component and a texture component.
FIG. 13 is a diagram illustrating an example of an entire image including a plurality of multi-images.
FIG. 14 is a block diagram illustrating another configuration example of a television receiver to which the present invention has been applied.
FIG. 15 is a diagram illustrating an example of an entire image including a plurality of multi-images.
FIG. 16 is a flowchart illustrating a texture amplification process in the texture amplification circuit of FIG. 14;
[Explanation of symbols]
2 image processing section, 3 display, 14 multi-screen processing section, 15 texture enhancement section, 16 delay circuit, 17 chroma amplifier, 18 contour correction circuit, 51 contour correction circuit, 52 texture amplification circuit, 53 structure correction circuit, 54 switch, 55 adder, 81 level determination unit, 82 frequency determination unit, 83 filter characteristic determination unit, 84 nonlinear filter, 85 subtractor, 101 gamma curve generation circuit, 102 gain adjustment circuit, 103 delay circuit, 104 adder, 200 whole image , 410 texture enhancement unit, 411 DE area conversion unit, 412 switch

Claims (6)

In an image processing apparatus for processing an image,
Data separation means for separating input image data including data of a plurality of multi-images simultaneously displayed on one screen into a structure component constituting a contour of the multi-image and a texture component constituting details of the multi-image;
Texture enhancement means for enhancing the texture component separated by the data separation means,
Structure correction means for performing non-linear correction on the structure components separated by the data separation means,
The texture component emphasized by the texture emphasizing means, and a selecting means for selecting any one of the texture components not emphasized,
Synthesizing means for synthesizing the structure component corrected by the structure correcting means and the texture component emphasized by the texture emphasizing means selected by the selecting means to generate processed data;
An image processing apparatus, comprising: display control means for controlling a plurality of multi-images to be displayed on one screen based on the processed data synthesized by the synthesis means. The image processing apparatus according to claim 1, further comprising a frame signal output unit that outputs a frame signal indicating that the frame is a frame of the multi image. When the frame signal indicating the frame of the multi-image is output from the frame signal output unit, the selection unit selects the non-emphasized texture component and supplies the texture component to the synthesis unit. The image processing apparatus according to claim 2, wherein: The image processing apparatus according to claim 2, wherein the frame signal output unit outputs a frame signal indicating that the frame is a frame of the multi image when the image is not in the image display period of the multi image. The frame signal output unit may further output a frame signal indicating that the frame is a frame of the multi-image during an image display period of the multi-image and within a predetermined range near an edge of the multi-image. The image processing apparatus according to claim 4, wherein: In an image processing method of an image processing apparatus that processes an image,
A data separation step of separating input image data including data of a plurality of multi-images displayed simultaneously on one screen into a structure component forming a contour of the multi-image and a texture component forming details of the multi-image;
A texture emphasizing step of emphasizing the texture component separated by the processing of the data separating step;
A structure correction step of performing non-linear correction on the structure component separated by the processing of the data separation step;
A selection step of selecting one of the texture component emphasized by the processing of the texture emphasis step and the texture component that is not emphasized;
A combining step of combining the structure component corrected by the processing of the structure correction step and the texture component selected by the processing of the selection step to generate processed data;
A display control step of controlling the plurality of multi-images to be displayed on one screen based on the processed data synthesized by the processing of the synthesizing step.

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