JP5487785B2 - Video recording / reproducing apparatus and image display apparatus - Google Patents

Description

  The present invention relates to a video recording / reproducing apparatus for recording / reproducing a video signal enhanced with respect to an input signal and an image display apparatus for displaying the video signal. The video recording / reproducing apparatus includes an enhancement processing circuit that performs high frequency component enhancement processing on the video signal in order to obtain an output signal with high resolution, and performs enhancement processing on the recording signal or the reproduction signal. Further, when both the video recording / reproducing apparatus and the image display apparatus are provided with a high frequency component enhancement processing circuit, only one of the enhancement processing circuits is controlled to operate.

  In a video recording / reproducing apparatus, an image display apparatus, or the like, signal enhancement processing may be performed for the purpose of obtaining an image with a high resolution.

  For example, in the image processing apparatus described in Patent Document 1, with respect to a detail image converted to multi-resolution, an enhancement coefficient for a detail image in a desired frequency band is lower than the desired frequency band. A desired frequency band is emphasized by setting based on a signal of a detailed image.

JP-A-9-44651 (paragraph 0031)

  However, in an image processing apparatus that appropriately sets an enhancement coefficient for a detail image in a desired frequency band with respect to a detail image converted to multi-resolution, the enhancement processing is inappropriate or insufficient depending on the input image. It was impossible to obtain an output image with high image quality.

  For example, when an image obtained by decompressing an image-compressed signal is input as an input image, a high-frequency component of the image is lost, and the image processing apparatus described in Patent Document 1 is a detailed image subjected to enhancement processing. In the region corresponding to the region of relatively low density in the lowest frequency band in FIG. 2, the enhancement degree is suppressed lower than that of the other areas, and the enhancement process is performed with the enhancement degree higher than that of the low density region for the other areas. High frequency components are emphasized, but the signal strength and the degree of enhancement are in a linear relationship, and it is not sufficient as an emphasis process that sharply raises the edge rise when the high frequency components of the input image are lost. there were.

  When an image subjected to noise processing is input as an input image, the frequency spectrum on the high frequency component side is lost due to noise processing. Therefore, even if an attempt is made to extract a high frequency component, it cannot be extracted, and image enhancement processing may not be performed sufficiently.

  Alternatively, when the enhancement processing circuit is provided in the video recording / reproducing apparatus and the image display apparatus, since the enhancement process is performed twice, excessive processing may appear as a defect in the output image.

  The present invention has been made in order to solve the above-described problems. When a video recording / playback apparatus equipped with an image resolution enhancement process and an image display apparatus are connected, excessive resolution enhancement is achieved. The purpose is to obtain an optimum image without becoming a problem.

A video recording / reproducing apparatus according to the present invention is a video recording / reproducing apparatus that transmits a video signal to an image display device and transmits / receives a control signal to / from the image display device,
First signal processing means for outputting a first video signal subjected to resolution enhancement processing using a reproduced video signal reproduced from data recorded on a recording medium as input, and controlling the first signal processing means A first control means for transmitting and receiving control signals to and from the image display device,
A first intermediate image generating unit configured to extract a component in the vicinity of a specific frequency band from the input reproduction video signal to generate a first intermediate image; and the first intermediate image A first intermediate image processing means for generating a second intermediate image having a high frequency component increased by applying a non-linear process, and a first addition means for adding the reproduced video signal and the second intermediate image. ,
When the first control means transmits and receives control information between the image display device and the first signal processing means, and recognizes that the connected image display device has a resolution enhancement processing function. It is characterized in that no resolution enhancement processing is performed.

An image display device according to the present invention is an image display device that receives a video signal from a video recording / playback device and transmits / receives a control signal to / from the video recording / playback device,
Second signal processing means for outputting a third video signal obtained by applying a resolution enhancement process to the second video signal input from the video recording / reproducing apparatus; and displaying the third video signal as an image. A monitor and a second control means for controlling the second signal processing means and transmitting and receiving control signals to and from the image display device;
Based on the control information of the first signal processing unit of the video recording / reproducing apparatus, the second control unit is configured to prevent the resolution enhancement process from being excessive. The emphasis processing is controlled.

  According to the present invention, the video recording / reproducing apparatus and the image display apparatus are connected by the video signal and the control signal, the degree of resolution enhancement processing in the video recording / reproducing apparatus is detected on the image display apparatus side, and the image display is performed. Since the resolution enhancement process of the apparatus is controlled, optimal image display can be performed without excessive resolution enhancement process.

1 is a configuration diagram of a video recording / reproducing apparatus and an image display apparatus according to Embodiment 1 of the present invention. 2 is a configuration diagram of a signal processing means 15. FIG. It is a block diagram of horizontal direction nonlinear processing means 152Ah. It is a block diagram of vertical nonlinear processing means 152Av. It is a block diagram of the weighted addition means 152C. It is another block diagram of the video recording / reproducing apparatus and image display apparatus by Embodiment 1 of this invention. FIG. 3 is a configuration diagram of an enlargement processing unit 14. FIG. 11 is an operation explanatory diagram of the enlargement processing unit 14. FIG. 11 is an operation explanatory diagram of the enlargement processing unit 14. FIG. 5 is an operation explanatory diagram of intermediate image generation means 151. FIG. 10 is an operation explanatory diagram of intermediate image processing means 152. It is explanatory drawing of the signal which sampled the step edge and step edge by sampling interval S1. It is explanatory drawing of the signal which sampled step edge and step edge by sampling interval S2. FIG. 6 is an operation explanatory diagram of intermediate image generation means 151 and intermediate image processing means 152. It is another block diagram of the video recording / reproducing apparatus and image display apparatus by Embodiment 1 of this invention. It is another block diagram of the video recording / reproducing apparatus and image display apparatus by Embodiment 1 of this invention. It is another block diagram of the video recording / reproducing apparatus and image display apparatus by Embodiment 1 of this invention.

Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of a video recording / reproducing apparatus and an image display apparatus according to Embodiment 1 of the present invention.

  In the video recording / reproducing apparatus 1, the input video signal is compressed in the compression processing unit 11 by a high-efficiency irreversible compression method such as MPEG-2, and then recorded by the access means 12. Or the like is written on the recording medium 2. The compressed data read from the recording medium 2 by the access unit 12 is restored to a video signal by a video signal reproduction process such as data decompression by the decompression processing unit 13, and then a high frequency component is added by the signal processing unit 15. Then, a video signal that has been subjected to signal processing that enhances the resolution of the image is output. Also, the video signal output from the video recording / reproducing apparatus 1 and input to the image display apparatus 3 is subjected to a resolution emphasis process such that a high frequency component is added by the signal processing means 32 to enhance the resolution of the image. After that, it is displayed on the monitor 33 as an image. The signal processing means 15 of the video recording / reproducing apparatus 1 is controlled by the control circuit 16, the signal processing means 32 of the image display apparatus 3 is controlled by the control circuit 34, and the control circuit 16 and the control circuit 34 mutually control data. Giving and receiving.

  FIG. 2 is a diagram showing the configuration of the signal processing means 15 in FIG. The configuration of the signal processing means 32 is the same. The signal processing unit 15 generates an intermediate image D151 that generates an intermediate image D151 obtained by extracting a component in the vicinity of a specific frequency band from the input signal DIN15, and an intermediate image process that generates an intermediate image D152 obtained by performing processing described later on the intermediate image D151. The adder 153 adds the means 152 and the input signal DIN15 and the intermediate image D152. The adder 153 adds the input signal DIN and the intermediate image D152 and outputs the result as the output signal DOUT15.

  The intermediate image generation unit 151 generates a high-frequency component image generation unit 151A that generates an image D151A in which only a high-frequency component is extracted from the input signal DIN15, and a low-frequency component image that generates an image D151B in which only a low-frequency component of the image D151A is extracted. It consists of generating means 151B. From the intermediate image generation means 151, an image D151B is output as an intermediate image D151.

  The intermediate image processing unit 152 outputs a non-linear processing unit 152A that outputs an image D152A obtained by performing non-linear processing described later on the intermediate image D151, and a high-frequency component image generating unit that outputs an image D152B obtained by extracting only the high-frequency component of the image D152A. 152B includes weight addition means 152C that outputs an image D152C obtained by adding the intermediate image D151 and the image D152B. From the intermediate image processing means 152, an image D152C is output as an intermediate image D152.

  Hereinafter, detailed operations of the video recording / reproducing apparatus 1 and the image display apparatus 3 according to the first embodiment of the present invention will be described.

  In the video recording / reproducing apparatus 1, the video input signal is compressed in the compression processing unit 11 by a high-efficiency irreversible compression method such as MPEG-2, and then recorded by the access means 12. It is written on the recording medium 2. The compressed data read from the recording medium 2 by the access unit 12 is restored to a video signal by a video signal reproduction process such as data decompression by the decompression processing unit 13, and then a high frequency component is added by the signal processing unit 15. Then, a video signal that has been subjected to signal processing that enhances the resolution of the image is output.

  In the image display device 3, the video signal from the video recording / playback device 1 is displayed on the monitor 33 after being subjected to signal processing by the high-frequency component added by the signal processing means 32 to enhance the resolution of the image. The operation of the signal processing means 32 is the same as that of the signal processing means 15 and will not be described.

  First, the operation of the signal processing means 15 will be described. In the signal processing means 15, the intermediate image generation means 151 generates an intermediate image D151 obtained by extracting a component in the vicinity of a specific frequency band from the input signal DIN15. Further, the intermediate image processing means 152 performs processing described later on the intermediate image D151. The performed intermediate image D152 is generated, the intermediate image D152 is added to the input signal DIN15, and a high frequency component is added to output the video signal DOUT15 in which the sense of resolution is enhanced.

  Hereinafter, a detailed operation of the intermediate image generating unit 151 will be described.

  First, the intermediate image generation unit 151 generates an image D151A in which only the high frequency component of the input image DIN is extracted in the high frequency component image generation unit 151A. That is, the horizontal high-frequency component image generation means 151Ah performs high-pass filtering in the horizontal direction on the input image DIN to generate an image D151Ah in which the high-frequency components are extracted only in the horizontal direction, and the vertical high-frequency component image generation means A high-pass filter process in the vertical direction is performed by 151Av to generate an image D151Av in which high frequency components are extracted only in the vertical direction. In this way, high-frequency components can be extracted by performing high-pass filter processing in each of the horizontal direction and vertical direction of an image.

  Next, the low frequency component image generation means 151B generates an image D151B obtained by extracting only the low frequency component of the image D151A. That is, an image D151Bh obtained by performing horizontal low-pass filter processing on the image D151Ah by the horizontal low-frequency component image generation unit 151Bh is generated, and a low-pass filter in the vertical direction with respect to the image D151Av by the vertical low-frequency component image generation unit 151Bv. The processed image D151Bv is generated. The intermediate image generating unit 151 outputs an image D151B composed of the image D151Bh and the image D151Bv as the intermediate image D151. The intermediate image D151 includes an image D151h corresponding to the image D151Bh and an image D151v corresponding to the image D151Bv.

  Next, a detailed operation of the intermediate image processing unit 152 will be described.

  First, the intermediate image processing unit 152 generates an image D152A obtained by performing a later-described nonlinear process on the intermediate image D151 in the nonlinear processing unit 152A. That is, non-linear processing described later is performed on the image D151Bh by the horizontal non-linear processing means 152Ah to generate an image D152Ah, and non-linear processing described below is performed on the image D151Bv by the vertical non-linear processing means 152Av to generate an image D152Av. To do. As described above, the nonlinear processing is performed in each of the horizontal direction and the vertical direction.

  The operation of the nonlinear processing means 152A will be described in more detail. The nonlinear processing means 152A includes a horizontal nonlinear processing means 152Ah and a vertical nonlinear processing means 152Av having the same configuration. Here, the horizontal nonlinear processing means 152Ah performs horizontal processing, and the vertical nonlinear processing means 152Av performs vertical processing.

  FIG. 3 is a diagram showing the configuration of the horizontal nonlinear processing means 152Ah. The horizontal non-linear processing means 152Ah includes a zero cross determining means 152Ah1 and a signal amplifying means 152Ah2. Note that the image D151h is input to the nonlinear processing means 152Ah as the input image DIN152Ah1.

  The zero cross determination means 152Ah1 confirms the change of the pixel value in the input image DIN152Ah1 along the horizontal direction. A point where the pixel value changes from a positive value to a negative value or from a negative value to a positive value is regarded as a zero cross point, and the positions of pixels before and after the zero cross point are transmitted to the signal amplifying unit 152Ah2 by the determination signal D152Ah1. To do. For example, pixels located on the left and right of the zero cross point are recognized as pixels located before and after the zero cross point.

  The signal amplifying unit 152Ah2 identifies pixels before and after the zero cross point based on the determination signal D152Ah1, and amplifies the pixel value only for the pixels before and after the zero cross point (increases the absolute value) D152Ah2 Is generated. That is, the amplification factor is set to a value larger than 1 for the pixel values of the pixels before and after the zero cross point, and the amplification factor is set to 1 for the pixel values of the other pixels.

  A non-linear processed image D152Ah2 is output as an image D152Ah from the horizontal non-linear processing means 152Ah.

  FIG. 4 is a diagram showing the configuration of the vertical nonlinear processing means 152Av. The vertical nonlinear processing means 152Av includes a zero cross determination means 152Av1 and a signal amplification means 152Av2. Note that the image D151v is input to the nonlinear processing means 152Av as the input image DIN152Av1.

  The zero cross determination means 152Av1 confirms the change in the pixel value in the input image DIN112Av1 along the vertical direction. A point where the pixel value changes from a positive value to a negative value or from a negative value to a positive value is regarded as a zero cross point, and the positions of the pixels before and after the zero cross point are transmitted to the signal amplifying unit 152Av2 by the determination signal D152Av1. To do. For example, pixels positioned above and below the zero cross point are recognized as pixels positioned before and after the zero cross point.

  The signal amplifying means 152Av2 specifies pixels before and after the zero-cross point based on the determination signal D152Av1, and amplifies the pixel value only for the pixels before and after the zero-cross point (increases the absolute value) D152Av2 Is generated. That is, the amplification factor is set to a value larger than 1 for the pixel values of the pixels before and after the zero cross point, and the amplification factor is set to 1 for the pixel values of the other pixels. A non-linear processed image D152Av2 is output as an image D152Av from the vertical non-linear processing means 152Av.

  The above is the operation of the nonlinear processing means 152A.

  Next, the high frequency component image generation unit 152B generates an image D152B obtained by extracting only the high frequency component of the image D152A. That is, an image D152Bh obtained by performing horizontal high-pass filter processing on the image D152Ah by the horizontal high-frequency component image generation unit 152Bh is generated, and a high-pass filter in the vertical direction for the image D152Av by the vertical high-frequency component image generation unit 152Bv. The processed image D152Bv is generated. In this way, high-frequency components are extracted in the horizontal and vertical directions of the image.

  Next, the weighted addition unit 152C performs weighted addition on the intermediate image D151 and the image D152B to generate an image D152C. Note that the intermediate image D151 includes an image D151h and an image D151v, and the image D152B includes an image D152Bh and an image D152Bv. It means adding all of D152Bv. The intermediate image processing unit 152 outputs the image D152C as the intermediate image D152.

  FIG. 5 is a diagram showing the configuration of the weighted addition means 152C. Respective input signals D151h, D151v, D152Bh, D152Bv are multiplied by multiplication means 1521Ch, 1521Cv, 1522Ch, 1522Cv, and further added by an adder circuit 1523 to be output as an image D152C to be an intermediate image D152. The coefficient of each multiplication means is controlled by the control signal D16S, and the ratio of high frequency components, that is, the degree of resolution is controlled. When the image display device is connected, the control signal D16S does not perform resolution enhancement processing so that all coefficients are set to 0, or when the image display device is connected, the coefficient is lowered by the control signal D16S. In this way, it is possible to make the resolution enhancement process weak.

  The operation of the adding means 153 will be described. The adding unit 153 generates an output image DOUT15 obtained by adding the input image DIN15 and the intermediate image D152. The output image DOUT15 is output as the final output image.

  The operation of the signal processing unit 15 has been described above. The case where the enlargement processing unit 14 is provided in the preceding stage of the signal processing unit 15 as shown in FIG. Thus, it is considered that this also serves as an explanation of a method of enhancement processing that compensates for high-frequency components lost when the decompression circuit 13 in the configuration of the present application decompresses and reproduces. The enlargement processing unit 14 generates, for example, an image obtained by enlarging the input image signal twice in both the horizontal direction and the vertical direction. The Nyquist frequency of the enlarged image signal is the same as that of the input image DIN14. It becomes half of the Nyquist frequency Fn.

  FIG. 7 is a diagram illustrating a configuration example of the enlargement processing unit 14. The enlargement processing unit 14 includes a horizontal direction zero insertion unit 141, a horizontal direction low frequency component passage unit 142, a vertical direction zero insertion unit 143, and a vertical direction low frequency component passage unit 144. The horizontal direction zero insertion means 141 generates an image D141 in which pixels having a pixel value 0 in the horizontal direction of the input signal DORG are appropriately inserted. The horizontal low frequency component passing means 142 generates an image D142 in which only the low frequency component of the image D141 is extracted by low pass filter processing. The vertical zero insertion unit 143 generates an image D143 in which pixels having a pixel value of 0 in the vertical direction of the image D142 are appropriately inserted. The vertical low frequency component passing means 144 generates an image D144 obtained by extracting only the low frequency component of the image D143. The image D144 is output from the enlargement processing unit 14 as an image obtained by doubling the original image DORG in both the horizontal and vertical directions.

  FIG. 8 is a diagram for explaining the operation of the enlargement processing means 14 in detail. FIG. 8A shows the original image DORG, FIG. 8B shows the image D141, FIG. 8C shows the image D142, and FIG. 8D represents the image D143, and FIG. 8E represents the image D144. 8A to 8E, a square represents a pixel, and a symbol or a numerical value written therein represents a pixel value of each pixel.

  The horizontal direction zero inserting means 141 inserts one pixel having a pixel value of 0 for each pixel in the horizontal direction into the original picture DORG shown in FIG. 8A, and creates an image D141 shown in FIG. 8B. Generate. The horizontal direction low frequency component passing means 142 performs low pass filter processing on the image D141 shown in FIG. 8B to generate an image D142 shown in FIG. The vertical zero insertion means 143 inserts one pixel having a pixel value of 0 for each pixel in the vertical direction into the image D142 shown in FIG. 8C, and creates an image D143 shown in FIG. 8D. Generate. The low frequency component passing means 144 in the vertical direction performs low-pass filter processing on the image D143 shown in FIG. 8D, and generates an image D144 shown in FIG. With the above processing, an image D144 obtained by enlarging the original image DORG twice in both the horizontal and vertical directions is generated.

  FIG. 9 shows the effect of processing by the enlargement processing means 14 on the frequency space. FIG. 9A shows the frequency spectrum of the original picture DORG, and FIG. 9B shows the frequency response of the horizontal frequency component passing means 142. Represents. In FIG. 9, the horizontal axis represents the frequency axis representing the spatial frequency in the horizontal direction, and the vertical axis represents the frequency spectrum or the intensity of the frequency response. Note that the number of pixels of the original image DORG is half that of the input image DIN. In other words, the sampling interval of the original image DORG is twice the sampling interval of the input image DIN. Therefore, the Nyquist frequency of the original image DORG is half of the Nyquist frequency of the input image DIN, that is, Fn / 2.

  In FIG. 9, only one frequency axis is used to simplify the notation. However, usually, image data consists of pixel values given on a pixel array arranged in a two-dimensional plane, and its frequency spectrum is also given on a plane stretched by a horizontal frequency axis and a vertical frequency axis. It is. Therefore, in order to accurately represent the frequency spectrum of the original picture DORG or the like, it is necessary to describe both the horizontal frequency axis and the vertical frequency axis. However, the shape of the frequency spectrum usually spreads isotropically around the origin on the frequency axis, and as long as the frequency spectrum in the space spanned by one frequency axis is shown, the frequency axis It is easy for those skilled in the art to expand and consider the space spanned by two. Therefore, unless otherwise specified in the following description, the description on the frequency space is performed using a space stretched by one frequency axis.

  First, the frequency spectrum of the original picture DORG will be described. Normally, a natural image is input as the original image DORG, but its spectral intensity is concentrated around the origin of the frequency space. Therefore, the frequency spectrum of the original picture DORG is a spectrum SPO represented as shown in FIG.

  The frequency spectrum of the image D142 will be described. An image D142 is obtained by performing low-pass filter processing having the frequency response shown in FIG. 9B on the image D141. Therefore, as shown in FIG. 9C, the frequency spectrum of the image D142 includes a spectrum SP1 in which the intensity of the spectrum SPO has dropped to some extent. In general, the frequency response of the low-pass filter decreases as the frequency increases. Therefore, when the intensity of the spectrum SP1 is compared with the spectrum SPO, the spectrum intensity on the high frequency component side, that is, the frequency near ± Fn / 2 is reduced by the horizontal low frequency component passing means 142.

  Of the processing by the image enlarging means 14, the description of the operation on the frequency space of the processing by the vertical zero insertion means 143 and the vertical low frequency component passing means 144 is omitted, but from the contents of the processing. It can be easily understood that there is an action similar to the content described with reference to FIG. 9 with respect to the axial direction representing the vertical spatial frequency. That is, the frequency spectrum of the image D144 is obtained by spreading the frequency spectrum shown in FIG. 9B in two dimensions.

Hereinafter, the operation and effect of the signal processing means 15 on the image that has been enlarged will be described.

  10A to 10E schematically illustrate the operation and effect when the intermediate image D1 is generated from the input image DIN15 when the image D144 obtained by enlarging the original image DORG is input as the input image DIN15. 10A shows the frequency spectrum of the input image DIN15, FIG. 10B shows the frequency response of the high-frequency component image generating means 151A, and FIG. 10C shows the low-frequency component image generation. FIG. 10D shows the frequency response of the means 151B, FIG. 10D shows the frequency response of the intermediate image generation means 151, and FIG. 10E shows the frequency spectrum of the intermediate image D151. In FIG. 10, only one frequency axis is used for the same reason as in FIG.

  Further, in FIG. 10, the intensity of the frequency spectrum or frequency response is shown only in the range where the spatial frequency is 0 or more. However, the frequency spectrum or frequency response in the following description is symmetrical about the origin on the frequency axis. Shape. Therefore, the figure used for description is sufficient to show only the range where the spatial frequency is 0 or more.

  First, the frequency spectrum of the input image DIN15 will be described. Since the image D144 is input as the input image DIN15, the frequency spectrum of the input image DIN15 has the same shape as that illustrated in FIG. 9C, as shown in FIG. 10A, and the spectrum of the original image DORG It consists of a spectrum SP1 in which the intensity of SPO drops to some extent.

  Next, the frequency response of the high frequency component image generating unit 151A will be described. Since the high frequency component image generating means 151A is constituted by a high pass filter, the frequency response becomes lower as the frequency becomes lower as shown in FIG.

  Next, the frequency response of the low frequency component image generation means 151B will be described. Since the low frequency component image generating means 151B is constituted by a low pass filter, the frequency response thereof becomes lower as the frequency becomes higher as shown in FIG.

  Next, the frequency response of the intermediate image generating unit 151 will be described. Among the frequency components of the input image DIN15, the frequency components in the low frequency component side region RL1 shown in FIG. 10D are weakened by the high frequency component image generating unit 151A in the intermediate image generating unit 151. On the other hand, the frequency component in the region RH1 on the high frequency component side shown in FIG. 10D is weakened by the low frequency component image generating unit 151B in the intermediate image generating unit 151. Therefore, as shown in FIG. 10D, the frequency response of the intermediate image generating unit 151 peaks in the intermediate region RM1 whose band is limited by the region RL1 on the low frequency component side and the region RH1 on the high frequency component side. It will have.

  Next, the frequency spectrum of the intermediate image D151 will be described. The input image DIN15 having the frequency spectrum shown in FIG. 10A passes through the intermediate image generating means 151 having the frequency response shown in FIG. 10D, so that the intermediate image D151 is obtained. Then, as shown in FIG. 10D, the frequency response of the intermediate image generating means 151 has a peak in the intermediate region RM1 that is band-limited by the region RL1 on the low frequency component side and the region RH1 on the high frequency component side. Therefore, the frequency spectrum of the intermediate image D151 is such that the intensity of the portion included in the low frequency component side region RL1 and the high frequency component side region RH1 of the frequency spectrum of the input image DIN15 is weak. Therefore, the intermediate image D151 is a high frequency component of the input image DIN15.

  FIGS. 11A to 11C are views showing the operation and effect of the intermediate image processing unit 152. FIG. 11A shows the frequency spectrum of the nonlinear processed image D152A, and FIG. 11B shows the high frequency component. FIG. 11C shows the frequency response of the image 152B, and FIG. 11C shows the frequency spectrum of the image D152B. In FIG. 11, for the same reason as in FIG. 13, the frequency spectrum or the intensity of the frequency response is shown only in the range where the spatial frequency is 0 or more.

  As will be described later, in the nonlinear processed image D152A, a high frequency component corresponding to the region RH2 on the high frequency component side is generated. FIG. 11A is a diagram schematically showing the state. The image D152B is generated when the nonlinear processed image D152A passes through the high frequency component image generation unit 152B. The high frequency component image generating means 152B is composed of a high-pass filter, and the frequency response becomes higher as the frequency becomes higher as shown in FIG. Therefore, the frequency spectrum of the image D152B is obtained by removing the component corresponding to the region RL2 on the low frequency component side from the frequency spectrum of the nonlinear processed image D152A as shown in FIG. In other words, the nonlinear processing unit 152A has an effect of generating a high frequency component corresponding to the region RH2 on the high frequency component side, and the high frequency component image generating unit 152B has only the high frequency component generated by the nonlinear processing unit 152A. There is an effect to take out.

  The above operation and effect will be described in detail using the case where the length of the sampling interval is twice as a case where the high frequency component is deteriorated as described above and the image is blurred.

  12 and 13 are diagrams showing signals obtained when sampling the step edge. 12A shows the step edge and the sampling interval S1, FIG. 12B shows a signal obtained when the step edge is sampled at the sampling interval S1, and FIG. 12C shows FIG. It represents the high frequency component of the signal represented in (B). On the other hand, FIG. 13A shows a sampling interval S2 which is wider than the step edge and the sampling interval S1, and FIG. 13B shows a signal obtained when the step edge is sampled at the sampling interval S2. FIG. 13C shows high frequency components of the signal shown in FIG. In the following description, it is assumed that the length of the sampling interval S2 is twice the length of the sampling interval S1.

  As shown in FIGS. 12C and 13C, the center of the step edge appears as a zero cross point Z in the signal representing the high frequency component. In addition, the slope of the signal representing the high frequency component near the zero cross point Z becomes steeper as the sampling interval is short, and the position of the point giving the local maximum and minimum values near the zero cross point Z is also The shorter the sampling interval, the closer to the zero cross point Z.

  That is, even if the sampling interval changes, the position of the zero crossing point of the signal representing the high frequency component does not change near the edge, but the slope of the high frequency component near the edge decreases as the sampling interval decreases (or the resolution increases). The position of the point that gives the local maximum and minimum values approaches the zero-cross point.

  FIG. 14 is a diagram showing the operation and effect when the signal obtained by sampling the step edge at the sampling interval S1 is doubled and then input to the image processing apparatus according to the present invention. In particular, the intermediate image generating means 151 and The operation and effect of the intermediate image processing means 152 are shown. As described above, since the processing inside the intermediate image generation unit 151 and the intermediate image processing unit 152 is performed in each of the horizontal direction and the vertical direction, the processing is performed one-dimensionally. Therefore, in FIG. 14, the contents of processing are expressed using a one-dimensional signal.

  FIG. 14A shows a signal obtained by sampling the step edge at the sampling interval S2 as in FIG. 13B. FIG. 14B is a signal obtained by enlarging the signal shown in FIG. 14A twice. That is, when the original image DORG includes an edge as shown in FIG. 14A, a signal as shown in FIG. 14B is input as the input image DIN14. Note that when the signal is doubled, the sampling interval is half that before the expansion, and therefore the sampling interval of the signal shown in FIG. 14B is the same as the sampling interval S1 in FIG. In FIG. 14A, the position represented by the coordinate P3 is the boundary portion on the low luminance side of the edge signal, and the position represented by the coordinate P4 is the boundary on the high luminance side of the edge signal.

  FIG. 14C shows a signal representing the high frequency component of the signal shown in FIG. 14B, that is, a signal corresponding to the image D151A output from the high frequency component image generating means 151A. Note that the image D151A is obtained by extracting the high frequency component of the input image DIN14.

  FIG. 14D shows a signal representing the low frequency component of the signal shown in FIG. 14C, that is, a signal corresponding to the image D151B output from the low frequency component image generating means 151B. Since the image D151B is output as the intermediate image D151 as described above, FIG. 14D corresponds to the intermediate image D151. As shown in FIG. 14D, the local minimum value in the vicinity of the zero cross point Z in the intermediate image D151 appears at the coordinate P3, and the local maximum value appears at the coordinate P4, which is shown in FIG. The step edge coincides with the high frequency component extracted from the signal sampled at the sampling interval S2.

  FIG. 14E shows an output signal when the signal shown in FIG. 14D is input to the nonlinear processing means 152A, that is, an image output from the nonlinear processing means 152A when the intermediate image D151 is input. D152A is shown. The nonlinear processing means 152A amplifies the signal values of the coordinates P1 and P2 before and after the zero cross point Z. Accordingly, as shown in FIG. 14E, in the image D152A, the magnitude of the signal value at the coordinates P1 and P2 is larger than the other values, and the position where the local minimum value appears near the zero cross point Z is the coordinate. The position where the local maximum value appears at the coordinate P1 closer to the zero cross point Z from P3 changes from the coordinate P4 to the coordinate P1 closer to the zero cross point Z. This means that the high frequency component is generated by the nonlinear processing in which the values of the pixels around the zero cross point Z are amplified in the nonlinear processing means 152A. In this way, it is possible to generate a high-frequency component by adaptively changing the amplification factor for each pixel or appropriately changing the content of processing according to the pixel. In other words, the nonlinear processing means 152A has an effect of generating a high frequency component not included in the intermediate image D151, that is, a high frequency component corresponding to the region RH2 on the high frequency component side shown in FIG.

  FIG. 14F shows a signal representing the high frequency component of the signal shown in FIG. 14E, that is, a signal corresponding to the image D152B output from the high frequency component image generating means 152B. As shown in FIG. 14 (F), the local minimum value near the zero cross point Z in the image D152B appears at the coordinate P1, and the maximum value appears at the coordinate P2, and this state shows the step edge shown in FIG. 12 (C). This coincides with the high frequency component extracted from the signal sampled at the sampling interval S1. This means that the high frequency component generated by the nonlinear processing means 152A is taken out by the high frequency component image generating means 152B and output as an image D152B. Further, it can be said that the extracted image D152B is a signal including a frequency component corresponding to the sampling interval S1. In other words, the high frequency component image generation unit 152B has an effect of extracting only the high frequency component generated by the nonlinear processing unit 152A.

  The weighted addition means 152C adds the weights for the intermediate image D151 and the image D152B and generates an image D152C. As described above, the intermediate image D151 is a high frequency component of the input image DIN15 and corresponds to a high frequency component near the Nyquist frequency of the original image DORG as shown in FIG. As described with reference to FIG. 9C, since the spectral intensity near the Nyquist frequency of the original image DORG is weakened by the enlargement process by the enlargement unit 14, the spectrum weakened by the enlargement process by adding the intermediate image D151. Strength can be supplemented.

On the other hand, the image D152B is a high frequency component corresponding to the sampling interval S1.
Therefore, the addition means 153 adds the image D152C (intermediate image D152) obtained by adding the intermediate image D151 and the image D152B to the input image DIN15, so that a high frequency component in a band equal to or higher than the Nyquist frequency of the original image DORG, that is, FIG. It is possible to add high frequency components obtained by sharply amplifying signals before and after the zero cross point Z shown in (F), and to enhance the resolution of the image.

  Furthermore, in the signal processing unit 15, the intermediate image generation unit 151 and the intermediate image processing unit 152 perform the processing related to the horizontal direction of the image and the processing related to the vertical direction in parallel, so only the horizontal direction of the image or only the vertical direction is performed. The above effects can be obtained with respect to an arbitrary direction.

  Further, the signal processing means 15 considers a component in the input image DIN in the vicinity of the Nyquist frequency ± Fn / 2 (or a specific frequency band) of the original image DORG out of the frequency band extending from the origin to Fn in terms of the frequency space. Originally, the image D152B corresponding to the high frequency component near the Nyquist frequency ± Fn is generated. Therefore, even if the frequency component near the Nyquist frequency ± Fn is lost in the input image DIN15 for some reason, the frequency component near the Nyquist frequency ± Fn can be given by the image D152B.

  The location used as the specific frequency band is not limited to the vicinity of ± Fn / 2. That is, the frequency band to be used can be changed by appropriately changing the frequency response of the high-frequency component image generation unit 151A and the low-frequency component image generation unit 151B.

  In the above description, as in the configuration of the present application, when irreversible compression is used as the image compression method for the purpose of reducing the data amount of the original signal for data transmission / storage, etc., the recording medium When the decompression circuit 13 decompresses and reproduces the data recorded in the image, the higher the compression ratio, the higher the frequency component is lost and the image becomes blurred. Therefore, the edge portion when the image is enlarged is blurred. This example is given as an example of a sluggish edge, and even if such deterioration occurs, this circuit can perform enhancement processing to compensate for lost components as described above. It is.

  The signal processing means 15 in the video recording / reproducing apparatus 1 and the signal processing means 32 in the image display apparatus 3 operate as described above, thereby enhancing the image resolution in the video recording / reproducing apparatus 1 and the image display apparatus 3, respectively. It is possible. As long as the emphasis processing is performed individually, the image quality improvement effect can be expected. However, if the above-described operation performs the emphasis processing in each of the video recording / playback apparatus 1 and the image display apparatus 3, it is an excessive emphasis process and is effective. Therefore, it is necessary to control so that double emphasis processing is not performed.

  Specifically, when the video recording / reproducing apparatus 1 and the image display apparatus 3 are connected by an HDMI (High-Definition Multimedia Interface) cable, for example, the control signal is based on CEC (Consumer Electronics Control) information of the 13th pin in the type A connector. Exchange. By referring to this control signal, it is possible to specify the device manufacturer, the device-specific information, and the like. Through the exchange of signals, it is possible to specify that the video recording / reproducing apparatus 1 and the image display apparatus 3 are apparatuses that perform the enhancement processing by the enlargement processing means 14 and 31 and the signal processing means 15 and 32, respectively. . The manufacturing ID can also be specified by referring to a signal defined as EDID (Extended Display Identification Data) for serial communication using the three lines of the 15th, 16th, and 17th pins in the type A connector of the HDMI cable. By doing so, the same control is possible.

  Next, the operation after the video recording / reproducing apparatus 1 and the image display apparatus 3 have been identified as the apparatuses that perform the enhancement process by the signal processing means will be described. The control circuit 16 and the control circuit 34 in FIG. 1 perform control so that either one of the video recording / reproducing apparatus 1 and the image display apparatus 3 is not emphasized. In either case, there is no problem, but here, control is performed so that the enhancement processing in the video recording / reproducing apparatus 1 is not performed. A control signal D16S is sent from the control circuit 16 to the signal processing unit 15. The control signal D16S is input to the weighted addition unit 152C of the intermediate image generation unit 152 in the signal processing unit 15 as shown in FIG. The weighted addition means 152C performs weighted addition on the images D151h, D151v, D152Bh, and D152Bv based on the control signal D16S.

  When the control signal D16S for not performing enhancement processing is input in the weighted addition means 152C of FIG. 5, the multiplication means 1521Ch, 1521Cv, 1522Ch, 1522Cv multiplies the input signals by 0. As a result, the values of the output signals D1521Ch, D1521Cv, D1522Ch, D1522Cv of the multiplication means are 0, and the value of the image signal D2 that is the addition result thereof is 0. In the addition circuit 153 in FIG. 2, the input signal DIN15 and the image signal D152 having a value of 0 are added, so that the input signal DIN15 is output as it is. With the above operation, the signal processing unit 15 in the video recording / reproducing apparatus 1 is controlled not to perform the enhancement process, and the signal processing unit 33 in the image display apparatus 3 performs the enhancement process. Thereby, the double emphasis process is not performed, and a suitable emphasis process is performed.

  In the above description, the signal processing unit 15 is configured not to perform the enhancement process by setting the intermediate image D152 added to the input signal by the adding unit 153 to 0. However, as shown in FIG. The delay circuit 17 and the switch circuit 18 are added to the device 1, and the delay circuit 36 and the switch circuit 37 are added to the image display device 3, so that the internal signal of the signal processing unit 32 can be controlled in the switch circuit 37. By selecting the delayed signal output, it is possible to adopt a configuration in which the enhancement processing is not performed.

  It is also possible to adopt a configuration as shown in FIG. 16 in which the delay circuit 17 of the video recording / playback apparatus 1 and the delay circuit 36 of the image display apparatus 3 in the configuration of FIG. In this configuration, the delay circuit can be reduced. On the other hand, when emphasis processing is not performed, that is, when a signal side that does not pass through the signal processing units 15 and 32 is selected in the switch circuits 18 and 37, the moment when the switch circuits 18 and 37 are switched. A pixel shift corresponding to the processing time in the signal processing units 15 and 32 occurs.

  In the above description, the video enhancement processing is performed on the output signal from the access means 12, but as shown in FIG. 17, the signal processing unit 19 corresponding to the signal processing unit 15 in FIG. After the emphasis process is performed, the signal may be input to the access unit 2 and recorded on the recording medium, and the signal processing unit 19 may be similarly controlled by the control circuit 16.

  In the above description, the video recording / playback apparatus that records and plays back video has been described. However, the video recording / playback apparatus may be a video playback apparatus that plays back video.

  In the above description, a circuit that performs video enhancement processing in both the video recording / playback apparatus and the image display device is provided, and the case where one of the enhancement processing is not performed or the degree of enhancement processing is weakened is described. However, if signal processing circuits such as color conversion and noise reduction are provided in both the video recording / reproducing apparatus and the image display apparatus, the degree of each is controlled so that signal processing is not excessively performed. It is not limited to emphasis processing.

  DESCRIPTION OF SYMBOLS 1 Video recording / reproducing apparatus, 2 Recording media, 3 Image display apparatus, 11 Compression processing means, 12 Access means, 13 Expansion processing means, 14 Expansion processing means, 15 Signal processing means, 16 Control circuit, 32 Signal processing means, 33 Monitor , 34 control circuit, 151 intermediate image generation means, 152 intermediate image processing means, 153 weighted addition means.

Claims (14)

A video recording / reproducing device that sends a video signal to an image display device and transmits / receives a control signal to / from the image display device,
First signal processing means for outputting a first video signal that has been subjected to a resolution enhancement process using a reproduced video signal obtained by reproducing data recorded on a recording medium;
A first control means for controlling the first signal processing means and for transmitting and receiving control signals to and from the image display device;
A first intermediate image generating unit configured to extract a component in the vicinity of a specific frequency band from the input reproduction video signal to generate a first intermediate image; and the first intermediate image A first intermediate image processing means for generating a second intermediate image having a high frequency component increased by applying a non-linear process, and a first addition means for adding the reproduced video signal and the second intermediate image. ,
When the first control means transmits and receives control information of the image display device and the first signal processing means, and recognizes that the connected image display device has a resolution enhancement processing function, A video recording / reproducing apparatus characterized by not performing resolution enhancement processing.   The degree of resolution enhancement processing is controlled by controlling the second intermediate image output from the first intermediate image processing means based on a control signal of the first control means. The video recording / reproducing apparatus according to claim 1.   The first intermediate image generation means includes first high frequency component image generation means for generating a first high frequency component image obtained by extracting only a high frequency component from the input reproduction video signal, and the first high frequency component image generation means. 3. The video recording / reproducing apparatus according to claim 2, further comprising first low-frequency component image generation means for extracting only the low-frequency component of the high-frequency component image. The first intermediate image processing means includes first nonlinear processing means for generating a nonlinear processed image obtained by amplifying each pixel value of the first intermediate image with an amplification factor changed according to the pixel, and the nonlinear processing. A second high-frequency component image generating means for generating a second high-frequency component image obtained by extracting only the high-frequency component of the image, and a first for adding the first intermediate image and the second high-frequency component image 4. The video recording / reproducing apparatus according to claim 3 , further comprising weighted addition means. The first high-frequency component image generation means generates a first horizontal high-frequency component image obtained by extracting a high-frequency component using pixels existing in the horizontal direction of each pixel of the input reproduction video signal. First horizontal high-frequency component image generating means and a first vertical high-frequency component image obtained by extracting a high-frequency component using pixels existing in the vertical direction of each pixel of the input reproduced video signal The first vertical high-frequency component image generating means for generating the first low-frequency component image generating means extracts the first low-frequency component of the first horizontal high-frequency component image. First horizontal low-frequency component image generating means for generating a horizontal intermediate image of the first and a first vertical intermediate image obtained by extracting only the low-frequency component of the first vertical high-frequency component image Video recording and reproducing apparatus according to claim 4, characterized in that it has a vertical low-frequency component image generating means. The first non-linear processing means generates first horizontal non-linear processing image obtained by amplifying each pixel value of the first horizontal intermediate image with an amplification factor changed according to the pixel. And a first vertical nonlinear processing means for generating a vertical nonlinear processed image obtained by amplifying each pixel value of the first vertical intermediate image with an amplification factor changed according to the pixel,
The second high-frequency component image generation means is a second horizontal high-frequency component image generation means for generating a second horizontal high-frequency component image obtained by extracting only the high-frequency component of the horizontal non-linear processing image. 6. The apparatus according to claim 5, further comprising second vertical high frequency component image generation means for generating a second vertical high frequency component image obtained by extracting only the high frequency component of the vertical nonlinear processing image. Video recording / playback device. The first horizontal non-linear processing unit is a first horizontal zero-cross point determining unit that determines, as a zero-cross point, a location where the pixel value of the first horizontal intermediate image changes from positive to negative or from negative to positive. And a first horizontal signal amplification means for determining an amplification factor for each pixel of the first horizontal intermediate image according to a determination result of the first horizontal zero-cross point determination means,
The first vertical direction non-linear processing means is a first vertical direction zero cross point determining means for determining a point where a pixel value of the first vertical intermediate image changes from positive to negative or from negative to positive as a zero cross point. And a first vertical signal amplifying means for determining an amplification factor for each pixel of the first vertical intermediate image according to the determination result of the first vertical zero-cross point determining means. The video recording / reproducing apparatus according to claim 6. An image display device that receives a video signal as a second video signal from the video recording / playback device and transmits / receives a control signal to / from the video recording / playback device,
Second signal processing means for outputting a third video signal obtained by performing resolution enhancement processing on the second video signal input from the video recording / reproducing device;
A monitor for displaying an image of the third video signal;
Second control means for controlling the second signal processing means and transmitting and receiving control signals to and from the image display device;
With
The first signal processing means of the video recording / reproducing apparatus performs a resolution enhancement process using a reproduced video signal obtained by reproducing data recorded on a recording medium as an input,
It said second control means, before SL on the basis of the control information of the first signal processing means, the control of the perceived resolution enhancement processing of the second signal processing means as sharpness enhancement processing is not excessive An image display device characterized in that it performs. A second intermediate image generating unit configured to extract a component in the vicinity of a specific frequency band from the input second video signal and generate a third intermediate image; and Second intermediate image processing means for generating a fourth intermediate image in which high-frequency components are increased by performing non-linear processing on the intermediate image; and second addition means for adding the reproduced video signal and the fourth intermediate image. Have
The degree of resolution enhancement processing is controlled by controlling the fourth intermediate image output from the second intermediate image processing means based on the control signal of the second control means. The image display device according to claim 8.   The second intermediate image generation means generates third high frequency component image generation means for generating a third high frequency component image obtained by extracting only the high frequency component from the input second video signal, and the third high frequency component image generation means. The image display apparatus according to claim 9, further comprising a second low-frequency component image generation unit that extracts only a low-frequency component of the high-frequency component image. The second intermediate image processing means generates second nonlinear processing means for generating a nonlinear processed image obtained by amplifying each pixel value of the third intermediate image according to a pixel, and the nonlinear processing A fourth high-frequency component image generating means for generating a fourth high-frequency component image obtained by extracting only the high-frequency component of the image, and a second for adding the third intermediate image and the fourth high-frequency component image The image display apparatus according to claim 10 , further comprising a weighted addition unit. The third high-frequency component image generation means obtains a third horizontal high-frequency component image obtained by extracting a high-frequency component using pixels existing in the vicinity of the horizontal direction of each pixel of the input second video signal. Third vertical high-frequency component image generation means that generates a third vertical high-frequency component image using a pixel existing in the vertical direction of each pixel of the input second video signal A third vertical high-frequency component image generating unit configured to generate a frequency component image, wherein the second low-frequency component image generating unit extracts only the low-frequency component of the third horizontal high-frequency component image; Second horizontal low-frequency component image generation means for generating a third horizontal intermediate image, and a third vertical intermediate image obtained by extracting only the low-frequency component of the third vertical high-frequency component image Generate The image display apparatus according to claim 11, characterized in that it comprises a second vertical low-frequency component image generating means. The second non-linear processing means generates a second non-linear processing image generated by amplifying a horizontal non-linear processing image with an amplification factor obtained by changing each pixel value of the third horizontal intermediate image according to the pixel. And second vertical nonlinear processing means for generating a vertical nonlinear processed image obtained by amplifying each pixel value of the third vertical intermediate image with an amplification factor changed according to the pixel,
A fourth horizontal high-frequency component image generating unit configured to generate a fourth horizontal high-frequency component image obtained by extracting only the high-frequency component of the horizontal nonlinear processed image; And a fourth vertical high-frequency component image generating means for generating a fourth vertical high-frequency component image obtained by extracting only the high-frequency component of the second vertical nonlinear processing image. 12. The image display device according to 12 . The second horizontal non-linear processing unit is a second horizontal zero cross point determining unit that determines, as a zero cross point, a portion where the pixel value of the third horizontal intermediate image changes from positive to negative or from negative to positive. And second horizontal signal amplification means for determining an amplification factor for each pixel of the third horizontal intermediate image according to a determination result of the second horizontal zero-cross point determination means,
The second vertical direction non-linear processing means is a second vertical direction zero cross point determining means for determining, as a zero cross point, a place where the pixel value of the third vertical intermediate image changes from positive to negative or from negative to positive. And a second vertical signal amplifying unit for determining an amplification factor for each pixel of the third vertical intermediate image in accordance with a determination result of the second vertical zero-cross point determining unit. The image display device according to claim 13.

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