KR100943902B1 - Ordinary image processing apparatus for digital TV monitor - Google Patents

Abstract

The present invention relates to a general-purpose image processing apparatus for a digital TV monitor that can be used in a display unit of a digital TV in connection with a digital TV tuner. In particular, the present invention relates to color coordinate conversion, which is various image processing blocks necessary for constructing a digital TV monitor. The video processing unit for the digital TV monitor can be effectively configured by optimally arranging the unit, the noise canceller, the format converter, the sequential scanning unit, the image enhancement unit, the PIP mux unit, the OSD unit, the lookup table, and the DAC. It can be used as a device to display existing TV images such as analog NTSC video, VGA ~ XGA, and digital TV video in various display modes such as main screen display, PIP display, POP, and dual screen display.

Image processing, digital TV monitor

Description

General purpose image processing apparatus for digital TV monitors {Ordinary image processing apparatus for digital TV monitor}

1 is an overall block diagram of a general-purpose image processing apparatus for a digital TV monitor according to the present invention.

FIG. 2 is a detailed block diagram illustrating an embodiment of the format converter of FIG. 1. FIG.

3 is a diagram illustrating an interpolation example using motion detection of the format converter of FIG. 1.

4 is a detailed block diagram illustrating an exemplary embodiment of a sequential scanning unit of the format conversion unit of FIG. 1.

5 is a diagram illustrating a histogram extraction example of the image quality improvement unit of FIG. 1;

6 is a detailed block diagram illustrating an exemplary embodiment of an outline sharpening unit of the image quality improving unit of FIG. 1.

Explanation of symbols for main parts of the drawings

101, 102: video input unit 101a, 102a: video input interface

101b and 102b: color coordinate conversion unit 101c and 102c: noise removing unit

101d, 102d: format conversion unit 103: post-processing unit

103a: switching unit 103b: image quality improving unit

103c: PIP mux 103d: OSD unit                 

103e: color coordinate conversion unit 103f: lookup table

103g: Sync waveform generator 103h: DAC section

104: host interface 105: synchronization generator

106: Buffer Bank 107: Graphics Engine

108: memory interface 109: memory arbiter

The present invention relates to a general purpose image processing apparatus for a digital TV monitor that can be used in a display unit of a digital TV in conjunction with a digital TV tuner.

In the United States, we have determined the broadcast specification for a fully digital high-definition television based on 8-VSB (Residual Side Band), MPEG (Moving Picture Experts Group) and Dolby AC (Audio Coding) -3. Since its implementation, all digital broadcast standards based on MPEG have been set worldwide. With the introduction of digital TVs, various types of TVs are currently being introduced.

For example, a built-in type digital TV including decoding and display of compressed digital images, as well as a digital TV tuner in the form of a STB (Set-Top Box) that performs only decoding functions, and digital TV. Various types of products are available, such as digital TV monitors that receive a tuner output or receive and display existing analog TV signals.                         

In particular, in the US, satellite broadcasts such as DirecTV have been commercialized through digital broadcasting, and the sales of digital TV tuners are on the rise. The demand for TV is increasing.

However, at the present time when the transition to digital TV is not completed, digital TV tuners and digital TV monitors, together with the demand of digital TV to directly receive and display digital broadcasts due to the mixed situation of analog and digital broadcasts, There is also a lot of demand to use together. In other words, digital TV tuners that use digital TV tuners that receive digital broadcasts and provide video and audio signals, and digital TV monitors that receive signals from digital TV tuners or display existing analog signals in high resolution There is also a lot of demand for watching analog TV at the same time.

In addition, while the United States and Korea's digital TV transmission standards have adopted the VSB scheme, the European region uses a transmission scheme based on Coded Orthogonal Frequency Division (COFDM). The disadvantage is that it is not compatible with digital TV. On the other hand, digital TV monitors have a merit that can be used irrespective of differences in transmission standards, and are currently widely used.

It is an object of the present invention to optimally combine various image processing functions required for such a digital TV monitor to efficiently display various types of input images in format conversion after receiving digital image signal input as well as existing analog TV signal. A general purpose image processing apparatus for a digital TV monitor is provided.

A feature of the general-purpose image processing apparatus for a digital TV monitor according to the present invention for achieving the above object is to optimally arrange various image processing functions required for a digital TV monitor, thereby outputting various types of output images for various types of input images. This is in the hardware structure of the image processing apparatus to make this happen.

The hardware structure of the general-purpose image processing apparatus for the digital TV monitor may include: a first image input unit configured to perform format conversion for easy display after performing color coordinate conversion and noise reduction on image data input in various forms; A second image input unit connected in parallel with the image input unit and performing format conversion for easy display after performing color coordinate conversion and noise reduction on image data input in various forms, and using a control signal according to a user's selection Selects and combines the image to be used as the main screen and the image to be used as the sub-screen from the image information provided by the first and second image input units, improves the image quality, inserts OSD data into the image screen, and then A post-processing unit for converting the color coordinates to the color coordinates of the display apparatus and outputting the first and second images; Memory interface for the interface between the synchronization signal generator for extracting the synchronization signal from the image signal input to the output unit to generate the necessary synchronization signal for each unit, and the external memory for storing intermediate images of the image or image processing input from outside Characterized in that it comprises a part.

Each of the first and second image input units may include an image input interface unit configured to detect various types of information about the input image such as the size of the input image, the frame rate of the input image, the scanning method of the input image, and the color coordinates of the input image. A color coordinate conversion unit for converting various color coordinates of the input image output from the image input interface unit into color coordinates of a predetermined shape, a noise removing unit for removing noise components included in the image input through the color coordinate conversion unit, and the noise component And a format converter for converting the resolution of the removed input image into the resolution of the display device.

The format converter may include a vertical format converter configured to enlarge or reduce an input image in a vertical direction, a horizontal format converter configured to enlarge or reduce an input image in a horizontal direction, and the front and rear sides of the vertical and horizontal format converters. A plurality of muxes positioned in front and rear, and a mode detector for controlling input / output data paths of the plurality of muxes according to the size of the input / output image, and the vertical format converter and the horizontal format converter according to the size of the input / output image, respectively. It is characterized by consisting of a clock providing unit for providing one of the clock and the clock for the display.

The format conversion unit may further include a sequential scanning unit for converting an interlaced scan image into a sequential scanning image.

The post processor may include a switching unit that separates an image to be displayed on a main screen and an image to be displayed on a sub-screen according to a control signal according to a user's selection among the image information output from the first and second image input units, and the switching unit. Image quality improvement unit for improving the image quality of the main screen image output through the PIP mux to synthesize the main screen image output from the image quality improvement unit and the sub-screen image output through the switching unit, and through the PIP mux An OSD unit for synthesizing OSD-type data on the output image screen, a color coordinate conversion unit for converting color coordinates of the image output from the OSD unit into color coordinates of a display device, and photoelectric transmission of the display device from the output of the color coordinate conversion unit A lookup table that compensates for characteristics and a high-quality sync signal are generated according to the standard And synchronizing the waveform generation unit which outputs a digital display device with, flower analog signals outputted from the synchronized waveform generating section is characterized by being composed of a digital / analog conversion for output to an analog display device.

The image quality improving unit may include an outline sharpening unit for sharpening the outline of the main screen image.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

1 is a block diagram illustrating a general image processing apparatus for a digital monitor according to an embodiment of the present invention. The first image input unit 101 converts image data input in various forms to be easily displayed by performing color coordinate conversion or format conversion. ), And arranged in parallel with the first image input unit 101 to receive an image, such as an image input to the first image input unit 101 or another image, to perform color coordinate conversion or format conversion for easy display. A picture in picture (PIP), picture out of picture (POP), and split-screen using the image data output from the second image input unit 102 to be converted and the first and second image input units 101 and 102. A post-processing unit 103, the first and second image input units 101 and 102, and a post-processing unit 103 to the external CPU to configure a screen such as The host interface unit 104 for controlling, the sync signal generator 105 for extracting a sync signal from an input video signal, and generating various display sync signals, and an intermediate process of an external image or image processing. It consists of a memory interface unit 108 for the interface with the memory for storing the.

The first image input unit 101 includes a video input interface 101a, a color space converter 101b, a noise reducer 101c, and a format converter. , 101d).

Similar to the first image input unit 101, the second image input unit 102 also functions as the image input interface unit 102a, the color coordinate conversion unit 102b, the noise removing unit 102c, and the format conversion unit 102d. The same block performs the same operation.

The post processing unit 103 includes a switch unit 103a, an image quality improving unit 103b, a PIP mux unit 103c, an OSD unit 103d, a color coordinate conversion unit 103e, a lookup table (LUT: Lookup Table, 103f). ), A tri-level generator 103g, and a digital-to-analog converter (DAC) 103h.

In the present invention configured as described above, the host interface 104 is a part responsible for interfacing with an external CPU, and supports a serial interface such as I ² C or a parallel interface such as an ARM or Motorola-based CPU. . In addition, the overall operation of the image processing apparatus 100 is determined and controlled. That is, the format conversion unit 101d and 102d of the first and second image input units 101 and 102 and the switching unit 103a of the post-processing unit 103 can be properly performed when two input images are output in an arbitrary display mode. ), The PIP mux unit 103c, the synchronization signal generator 105, and the like.

The memory interface unit 108 stores the plurality of input images in an external memory (for example, a synchronous DRAM or SDRAM) or reads images stored in the external memory so as to read the first and second image input units 101 and 102. Format conversion units 101d and 102d, and the OSD unit 103d of the post-processing unit 103. In this case, the format-converted image may be stored in the memory according to the input form and the display form, or the image before the format conversion may be stored in the memory.

In addition, between the memory interface unit 108 and the external memory, there is a memory arbiter 109 which is responsible for interfacing with an external memory, and the memory arbiter 109 is a memory such as a format converter, an OSD processor, a graphics engine, It provides memory usage right to the blocks it uses. In this case, the amount of memory used may vary depending on the display resolution and typically uses 8M / 4M bytes of SDRAM.

On the other hand, the first and second image input units 101 and 102 perform a proper image processing on the input image data so that the post processing unit 103 can easily configure the display screen. In this case, the first and second image input units 101 and 102 may be disposed in parallel to process images in the same manner with respect to two input images, and may easily synthesize screens such as PIP, POP, and dual screens. It is configured to be.

Here, as the image input to the first and second image input units 101 and 102, conventional analog image signals such as NTSC and PAL, PC signal output, and component images of various resolutions may be input. Shown in

   system    resolution    Aspect ratio   Scanning method     NTSC   720 * 480     4: 3   Interlaced injection     PAL   720 * 576     4: 3   Interlaced injection    PC output  1024 * 768     4: 3   Sequential injection   800 * 600     4: 3   Sequential injection   640 * 480     4: 3   Sequential injection Component output  1920 * 1080    16: 9   Interlaced injection  1280 * 720    16: 9   Sequential injection   852 * 480    16: 9 Sequential, interlaced injection   720 * 480   16: 9,4: 3 Sequential, interlaced injection   640 * 480     4: 3 Sequential, interlaced injection

In addition, the post processor 103 performs a function of synthesizing two images, image quality improvement, and image processing suitable for a final display. That is, the post processor 103 provides a signal necessary for a display device. Digital signals are output as they are for display devices with digital interfaces such as PDPs and LCDs.

The major output signal formats supported by the image processing apparatus 100 of the present invention are shown in Table 2 below.

   resolution    Aspect ratio   Scanning method Picture rate (Hz)  1920 * 1080    16: 9   Interlaced injection       60  1440 * 1080     4: 3   Interlaced injection       60  1366 * 768    16: 9   Sequential Scan       60  1024 * 768     4: 9   Sequential Scan       60  1280 * 720    16: 9   Sequential Scan       60   960 * 720     4: 9   Sequential Scan       60   852 * 480    16: 9   Sequential, interlaced       60   720 * 480  16: 9,4: 3   Sequential, interlaced       60   640 * 480     4: 3   Sequential, interlaced       60  1920 * 1080    16: 9   Interlaced injection       50   720 * 576  16: 9,4: 3   Sequential, interlaced       50

That is, the first and second image input units 101 and 102 separate the synchronization signal of the input image data accordingly, and easily convert the format by matching the color coordinates, and convert the input image format into the display resolution. Facilitates image processing in. In addition, the noise component of the input image is removed, and histogram information of the input image is extracted to be used in the post processor 103.

Here, since the internal operations of the first and second image input units 101 and 102 are the same, the first image input unit 101 will be described in detail by way of example.

The image input interface unit 101a of the first image input unit 101 detects and converts a variety of information about the input image, that is, the size of the input image, the frame rate of the input image, and the scanning method of the input image. For output to the color coordinate conversion unit 101b. In addition, since there are many cases in which abnormal image information is contained in the periphery of the image, such an image also plays a role of removing unnecessary images.

The color coordinate converter 101b converts an input image having various color coordinates into color coordinates suitable for format conversion and outputs the converted color coordinates to the noise removing unit 101c.

The color coordinates of a general image may have various color coordinates such as RGB, YCbCr, YUV, YIQ, and YDbDr. PC outputs such as VGA, SVGA, XGA, etc. generally have the form of RGB color coordinates. On the other hand, digital TV video based on MPEG generally has the form of YCbCr color coordinates. In addition, the conventional analog NTSC image has a color coordinate form such as YIQ or YUV. However, SECAM, which is widely used in Europe, has the same color coordinate format as YDbDr.

As described above, when various color coordinate images are input from the outside, the color coordinate converting unit 101b converts the color coordinates into a predetermined color coordinate form required by the format converting unit 101d. In addition, the color coordinate form is maintained in a constant shape until it is converted from the display processing unit to the color coordinate form of the display device, so that most image processing units need to consider only a constant color coordinate.

In addition, an image input to the image input unit 101 may be input in a 24-bit image form in which each of R, G, and B has 8 bits, as in an RGB image. Like YCbCr images, Y is 8 bits and 8 bits CbCr cross each other. It may be sampled and input in the form of an image of a total of 16 bits. In addition, in the case of NTSC, as described above, it may be input in 16-bit form, but may be input in 8-bit like D1 format. In this case, the color coordinate converting unit 101b also converts the input form into an appropriate form required by the format converting unit 101d as in the case described above, thereby effectively performing the format converting unit 101d and other image processing. can do.

In this case, the display device also needs an image of various color coordinates such as RGB and YPbPr. Therefore, separate color coordinate converting units 101b, 102c, and 103e are used for the first and second image input units 101 and 102 and the post processing unit 103, respectively.

For general color coordinate conversion, a conversion equation such as Equation 1 below may be used.

The operation of Equation 1 described above was implemented to enable multiplication at high speed of 80 MHz or more by implementing nine multipliers in a pipeline structure. The conversion equation when converting the YCbCr color coordinate image to the RGB color coordinate image by applying to Equation 1 is shown in Equation 2 below.

The conversion equation when converting an image of RGB color coordinates to an image of YCbCr color coordinates is shown in Equation 3 below.                     

The noise remover 101c removes a noise component that may exist in the input image and outputs the noise component to the format converter 101d.

In general, a digital TV signal receives a very clear image, but analog signals such as NTSC often contain noise components because of its weakness. In particular, the video output from an analog VCR contains a particularly severe noise component. Therefore, the noise removing unit 101c removes the noise component existing in the image before format conversion to prevent the noise component from being transferred to the post processor 103.

The video signal from which the noise is removed by the noise removing unit 101c is output to the format converter 101d.

Conventional analog TV has 525 lines of single format video signal for NTSC and 625 lines of single signal format for PAL or SECAM. On the other hand, digital TV can have a wide variety of image formats. In addition, due to the popularization of projectors and projection TVs, the display has been enlarged and the resolution of display devices has also become very diverse due to the emergence of new display devices such as PDPs and DLPs. For this reason, in the case of a digital TV monitor, the input resolution and the output resolution of the video signal are often different. For this purpose, it is necessary to use a format converter 101d for converting the resolution of the input video into the resolution of the output video.

2 is a block diagram showing an embodiment of the format conversion unit 101d, which has been filed by the present applicant (application number 2000-1420). In the format converter 101d of FIG. 2, a horizontal resolution and a vertical resolution of an input image may be independently controlled, and a clock used in the vertical format converter 201 and the horizontal format converter 202 may be used. By appropriately controlling the two format converters 201 and 202 effectively used.

That is, the format converter 101d includes a vertical format converter (VFC) 201 including a mux, a horizontal format converter (HFC) 202 including a mux, an input image and the vertical format converter 201. A mux 203 for selectively outputting any one of an output and an output of the horizontal format converter 202, a write control unit 204 for storing the output of the mux 203 in a memory through a memory interface 108, and the memory A read control unit 205 for reading the data stored in the memory interface 108 through the memory interface 108, an output of the vertical format converter 201, an output of the horizontal format converter 202, and an output of the read controller 205. The mux 206 for selectively outputting any one.

In this case, the mode is converted into a plurality of modes according to the size of the input image and the size of the output image, the mode detection unit 207 by controlling the data path of the input image through a plurality of mux located in the format conversion unit Is done.

The clock mux 208 provides the clock of the input image or the clock for display to the vertical format converter 201 and the horizontal format converter 202 according to the mode. That is, when the input image is enlarged or outputted as it is, a display clock is provided during format conversion, and when the input image is reduced, a clock of the input image is provided when format conversion is applied, which is equally applied to vertical and horizontal format conversion. .

First, when the horizontal resolution and the vertical resolution of the output image are equal to or larger than the horizontal / vertical resolution of the input image, the input image is first stored in a memory, and then the vertical format is converted while reading the image stored in the memory. The unit 201 and the horizontal format converter 202 sequentially increase the resolution of the image in the vertical direction and the horizontal direction, and output the image to the post processor 103.

In addition, when the horizontal resolution and the vertical resolution of the output image are both smaller than the horizontal / vertical resolution of the input image, the input image is passed through the horizontal format converter 202 and the vertical format converter 201 in order to provide a horizontal direction. And then reduce the resolution in the vertical direction and store it in the memory, and then immediately read the image reduced in the horizontal and vertical directions from the memory and output it to the processing unit 103.

When the resolution of the image increases in the horizontal direction and the resolution of the image decreases in the vertical direction, the input image is first passed through the vertical format converter 201 to reduce the resolution in the vertical direction, and then stored in the memory. . Thereafter, the image read out from the memory is input to the horizontal format converter 202 to increase the resolution of the image in the horizontal direction, and then output to the processor 103.

In addition, when the resolution of the image decreases in the horizontal direction and the resolution of the image increases in the vertical direction, the input image is first passed through the horizontal format converter 202 to reduce the resolution in the horizontal direction, and then stored in the memory. . Thereafter, the image read out from the memory is input to the vertical format converter 201 to increase the resolution of the image in the vertical direction, and then output to the processor 103.

The format converter 101d includes an interlaced / progressive converter (IPC), which sequentially interpolates interlaced scanning images such as standard-definition (SD) images of interlaced scanning or NTSC / PAL. It converts into high-definition (HD) image of the sequential scanning method.

The interlaced scan method is used in analog video such as NTSC or PAL as a method of increasing the resolution of an image by effectively using a given bandwidth by compressing a signal band of the video, and thus has been applied to digital TV. However, when the interlaced scanned image is simply converted into a format to convert the resolution of the image, serious image quality deterioration occurs. To avoid this, it is necessary to first convert the interlaced image into a sequential scan image.

3 illustrates an example of converting an interlaced scan image into a progressive scan image by an interpolation method using motion detection in the sequential scanning unit.

Progressive conversion unit in Fig. 3, the image of successive four fields namely, before the second field (T _i, T _j), that does not exist in T _k field by the current field (T _k), since the field (T _l) A 'z' pixel, which is a pixel, is continuously generated for every pixel.

4 is a detailed block diagram illustrating an exemplary embodiment of the sequential scanning unit, and determines whether there is a motion of an image by referring to image data around a 'z' pixel in time and space.

Referring to FIG. 4, the sequential scanning unit receives previous and subsequent field data based on current field data among field data for realizing an image, and detects a difference in brightness and a brightness contour pattern between field data to detect a motion degree of the video. A motion detector 401 for calculating a value, a maximum value detector 402 for measuring a motion degree value by mapping to a predetermined value when the brightness difference and the brightness contour pattern difference are greater than or equal to a predetermined threshold, and the noise included in the motion degree value. A median filter unit 403 for removing components and clustering the region having a movement degree value, a motion expansion unit 404 for extending the movement degree value to adjacent neighboring pixels, and a peripheral position among data of a current field Spatial interpolation unit 406 for generating interpolation data using pixel data, immediately before the current field The interpolation unit 407 generates interpolation data by using the pixel data present in the field immediately after the video signal, and the motion interpolation unit 404 indicates that there is motion of the image. If the output of the 406 is selected and it is indicated that there is none, it is composed of a switching unit 405 which is a selection unit for selecting the output of the time interpolation unit 407 and outputting interpolation data.

In this way 4 are configured, the motion detector 401 is the image that is, the current field (T _k) and current field (T _k) of the previous two-field basis (T _i, T _j), since the field of the four field sequential The degree of motion of the video is detected by detecting the difference between the pixel value and the brightness outline pattern of the specific lines existing between the field data using T _l . That is, the motion detector 401 calculates a brightness difference (Bd) between each field data and a brightness profile pattern difference (Pd: Brightness Profile Pattern Difference) between each field data, and outputs the same to the maximum value detector 402. When the brightness difference Bd and the brightness contour pattern difference Pd are equal to or greater than a predetermined threshold, the maximum value detector 402 measures a degree of movement by mapping to a predetermined value.

At this time, the image transmitted by the broadcast signal inevitably contains noise in the encoding step or the transmission step. Therefore, the median filter 403 removes such noise components from the output of the maximum value detector 402, and clusters the areas where the motion is detected in the image and outputs them to the motion extension unit 404. The motion extension unit 404 extends the motion degree value output from the median filter 403 to other adjacent pixels.

The reason why the motion extension unit 404 extends the motion degree value to adjacent pixels is as follows. In general, a motion of a video is not performed only in a specific pixel but in a pixel group of a predetermined region. Thus, if a motion degree value is detected for a particular pixel, it may be due to the noise component of the pixel, or the specific pixel and adjacent neighboring pixels may be in a motion state. However, since the motion degree value corresponding to the noise component has already been removed from the median filter 403, the surrounding pixels are likely to be in the motion state. Accordingly, the motion extension unit 404 diffuses the motion degree value output from the median filter 403 to the periphery of the pixel where the motion degree value is detected. The output of the motion expansion unit 404 is output to the switching unit 405.

The switching unit 405 outputs the interpolated data 'z' by selecting the output of the spatial interpolator 406 or the output of the temporal interpolator 407 according to the degree of motion output from the motion extension unit 404. .

), 새로운 화소 'z'를 생성하게 된다. The spatial interpolation unit 406 appropriately interpolates pixel data located around the data of the current field T _k (eg,

), A new pixel 'z' is generated.

), 새로운 화소 'z'를 생성하게 된다.The time interpolator 407 appropriately interpolates the 'c' pixels existing in the immediately preceding field T _j or the immediately following field T _l (eg,

), A new pixel 'z' is generated.

That is, when the output (a) of the motion extension unit 404 indicates that there is motion of the image, the switching unit 405 selects the pixel 'z' generated by the spatial interpolation unit 406 and indicates that there is no motion. In this case, the switching unit 405 selects and outputs the pixel 'z' generated by the time space unit 407.

In this case, when interpolation is performed using only the image positioned in the vertical direction when the pixel to be interpolated is positioned at the boundary of the image, there is a disadvantage in that a staircase-shaped image may be generated. Therefore, in this case, the exact inclination direction of the boundary portion is extracted and interpolation is performed in the inclination direction.

In conclusion, when converting interlaced scan image such as NTSC image into interlaced scan image of 1920x1080 resolution which is HD quality, first make sequential scan image by increasing vertical resolution by using sequential scanning unit and then use this format conversion unit. Therefore, if the image of 1920x540 resolution is implemented for each field, the image having the best image quality can be realized.

As described above, the format conversion unit 101d converts the resolution of the input image into the resolution of the display device and outputs the resolution to the post-processing unit 103.

The post processor 103 selects an image to be used as a main screen and an image to be used as a subscreen by using two image information output from the first and second image input units 101 and 102 and a control signal provided from a CPU, and combines the image appropriately. do. It also improves the quality of the main screen image and adds the user menu screen to the video screen to provide the final output.

That is, the switching unit 103a of the post processor 103 separates various input images into images to be displayed on the main screen and images to be displayed on the sub-screen, and then the main screen image is the image quality improving unit 103b. The sub screen image is output to the PIP mux 103c. Here, the image to be displayed on the main screen and the image to be displayed on the sub screen may vary depending on the display mode or input selection, and can be appropriately controlled by the user.

The image quality improving unit 103b applies necessary processing to the main screen image having the resolution of the display apparatus by format conversion, thereby providing an image quality suitable for the display apparatus. That is, the brightness, contrast, tint, sharpness, etc. of the image are adjusted to match the color characteristics of the display device. In addition, it performs image processing functions such as noise reduction and filtering as necessary.

5 shows a method of automatically adjusting the brightness of an image by calculating and storing a Cumulative Density Function (CDF) of an image input in FIG. 5 and applying this value when displaying the value. FIG. 5A is a histogram for a dark image, and FIG. 5B shows a CDF curve for the dark image of FIG. 5A. FIG. 5C is a histogram for a bright image, and FIG. 5D shows a CDF curve for the bright image of FIG. 5C. That is, it takes about 2 ~ 5 fields until the input image is stored in memory and displayed. Therefore, a large amount of data must be stored for this operation. In the present invention, in order to use the memory efficiently, only about 3 to 5 values are stored for the screen of each input image and interpolated later. Therefore, it is possible to greatly simplify the amount of storage required and obtain the desired image enhancement effect.

On the other hand, if the SD-level image is input and convert the format into a high-definition image, the sharpness of the image is reduced during the format conversion process. To this end, the image quality improvement unit 103b improves the sharpness of the image by using the contour sharpener as shown in FIG. 6. Due to the visual characteristics of humans, the sharpness of the image feels a great difference depending on the contrast level of the contour part. In other words, the greater the contrast of the contour, the sharper the feeling, which is possible by amplifying the high frequency components of the image. For example, amplifying high frequency components to signals with rapidly changing brightness increases contrast by causing overshoot and undershoot around the contour.                     

That is, the luminance signal Y is first low pass filtered in the first LPF LPF1, 601 and then output to the subtractor 602. The subtractor 602 outputs a difference signal between the input luminance signal Y and the low pass filtered signal in the first LPF 601 to the second LPF LPF2 603, and the second LPF 603 The difference signal is subjected to second order low pass filtering and output to the multiplier 605.

The multiplier 604 multiplies the second low pass filtered signal by a constant α, and then amplifies and outputs the result to a saturator 605. The separator 605 sets a specific bit of the multiplier 604. To do this. For example, the separator 605 M-bit from N-bit data means that when the N-bit data exceeds the range of bit values that can be represented by (NM) bits, the N-bit data is mapped to the value of the limit range. (mapping).

The output of the separator 605 is output to the adder 606, and the adder 606 adds and outputs the input luminance signal Y and the output of the separator 605.

On the other hand, the PIP mux unit 103c properly combines one or two image data inputted to provide an image such as PIP, POP, dual screen, and multi-PIP. For example, in the PIP display mode, the sub screen is inserted into the main screen to be displayed on the OSD unit 103d, and in the case of a POP screen or a dual screen, the main screen and the sub screen are displayed on separate screens. Output to the OSD unit 103d.

The OSD unit 103d is used together with a graphic engine 107 to synthesize an image such as a user's menu or subtitles on the image information and display the synthesized image. In this case, the OSD unit 103d supports display of any resolution and provides two independent OSD screens in addition to the hardware cursor. The graphic engine 107 provides a function of drawing a figure such as a point, a line, a rectangle at high speed, and provides a function of performing block copy at high speed while performing 16 logical operations.

The output of the OSD unit 103d is output to the color coordinate conversion unit (CSC) 103e, and the color coordinate conversion unit 103e converts the color coordinates of the image output from the OSD unit 103d into color coordinates of the display device. Output to lookup table (LUT) 103f.

The lookup table 103f compensates for the photoelectric transmission characteristics of the display device and outputs the same to the sync waveform generator 103g. That is, the lookup table 103f can be individually programmed for three independent components of R, G, B, or Y, Cb, and Cr to compensate for the photoelectric transmission characteristics of the display device. .

The synchronizing waveform generating unit 103g generates an HD class synchronizing signal in accordance with a standard and outputs the synchronizing signal to the display device together with the image signal to the DAC unit 103h. The DAC unit 103h converts the digital image data output from the sync waveform generator 103g into analog image data and outputs the analog image data. That is, the digital waveform data is simultaneously output from the sync waveform generator 103g in parallel with the output of the DAC unit 103h, and may be used in an analog display device or a digital display device as necessary. That is, the digital image data output from the sync waveform generator 103g is output for display on a display device having a digital interface such as a PDP or LCD, which is recently increasing.                     

The sync generator 105 provides a sync signal required for each part of the system. That is, the synchronization signal input together with the two input image signals provides the synchronization signal necessary for the external interface unit 104 and the format conversion unit 101d to properly process the image, and is synchronized with the display. Is generated and provided to the format conversion unit 101d, the switching unit 103a, the PIP mux unit 103c, the DAC unit 103h, and the like.

As described above, according to the general-purpose image processing apparatus for a digital TV monitor according to the present invention, a color coordinate conversion unit, a noise removing unit, a format conversion unit, and sequential scanning which are various image processing blocks necessary for constructing a digital TV monitor It is possible to effectively configure an image processing unit for a digital TV monitor by arranging an image unit, an image enhancement unit, a PIP mux unit, an OSD unit, a lookup table, a DAC, and the like.

In addition, the present invention can be used as a device for displaying in a variety of display modes, such as the main screen display, PIP display, POP, dual screen display, such as the conventional analog NTSC video, PC video such as VGA ~ XGA, and digital TV video Can be. In addition, as a display resolution, not only can be used for the existing analog NTSC output, but also can be used as a PC output, a standard definition output, and a high definition output.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.                     

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (11)

A first image input unit configured to perform color coordinate conversion and noise reduction on image data input in various forms, and then convert the resolution of the noise-removed image into a resolution of a display device and output the resolution; A second image which is connected in parallel with the first image input unit and performs color coordinate conversion and noise removal on image data input in various forms, and then converts the resolution of the noise-removed image to the resolution of the display device and outputs the second image; An input unit; Select and combine the image to be used as the main screen and the image to be used as the sub-screen from the image output from the first and second image input units by using the control signal according to the user's selection, insert the OSD data into the image screen, and then A post processor which converts the color coordinates of the color coordinates into color coordinates of the display apparatus and outputs the converted color coordinates; A synchronization signal generator for extracting a synchronization signal from the image data input to the first and second image input units and generating a synchronization signal for each unit; And A memory interface unit for interfacing with an external memory that stores an intermediate image of an image or an image processing input from the outside; Each of the first and second image input units includes a noise removing unit for removing noise of the color coordinate-converted image signal. And the post processing unit comprises a contour sharpening unit for sharpening the contour of the main screen image by using the luminance signal of the main screen image. The display apparatus of claim 1, wherein each of the first and second image input units comprises: An image input interface unit for detecting a variety of information about the input image such as the size of the input image, the frame rate of the input image, the scanning method of the input image, and the color coordinates of the input image; A color coordinate conversion unit for converting various color coordinates of the input image into color coordinates of a predetermined form by referring to the information of the input image output from the image input interface unit; A noise removing unit for removing noise components included in an image output through the color coordinate conversion unit; And a format conversion unit for converting the resolution of the input image from which the noise component is removed to the resolution of the display device. The method of claim 2, wherein the color coordinate conversion unit A general purpose image processing device for a digital TV monitor, characterized in that to perform color coordinate conversion by applying the following equation.

The method of claim 3, wherein the color coordinate conversion unit A general purpose image processing apparatus for a digital TV monitor, characterized by converting a YCbCr color coordinate image to an RGB color coordinate image by applying the following equation.

The method of claim 3, wherein the color coordinate conversion unit A general purpose image processing device for a digital TV monitor, characterized in that for converting an RGB color coordinate image to a YCbCr color coordinate image by applying the following equation.

The method of claim 2, wherein the format conversion unit A vertical format converter which enlarges or reduces an input image in a vertical direction; A horizontal format converter which enlarges or reduces an input image in a horizontal direction; A plurality of muxes positioned before and after the vertical and horizontal format converters, and before and after the external memory; A mode detector for controlling input / output data paths of the plurality of muxes according to sizes of input / output images; And a clock providing unit configured to provide one of a clock of an input image and a clock for display, respectively, to the vertical format converter and the horizontal format converter according to the size of the input / output image. The method of claim 6, wherein the vertical format conversion unit And a sequential scanning unit for converting interlaced scanning images into sequential scanning images. The method of claim 7, wherein the sequential scanning unit A motion detector which receives field data before and after the current field data among the field data implementing the image and detects a difference in brightness and a pattern of brightness contour between the field data and calculates a motion degree value of the video; A maximum value detector which measures a movement degree value by mapping to a predetermined value when the brightness difference and the brightness contour pattern difference are more than a predetermined threshold value; A median filter unit which removes a noise component included in the movement degree value and clusters a region having the movement degree value; A movement extension unit for extending the movement degree value to adjacent neighboring pixels; A spatial interpolation unit generating interpolation data by using pixel data positioned around the data of the current field; A time interpolation unit for generating interpolation data using pixel data existing in the immediately preceding field and the immediately following field based on the current field; And a selection unit for outputting interpolation data by selecting an output of the spatial interpolation unit when the movement degree value of the motion extension unit indicates that there is motion of an image, and indicating that there is no motion. Universal image processing unit for digital TV monitors. The method of claim 1, wherein the post-processing unit A switching unit for separating the image to be displayed on the main screen and the image to be displayed on the sub-screen according to a control signal according to a user's selection among the images output from the first and second image input units; An image quality improving unit for sharpening the outline of the main screen image output through the switching unit; A PIP mux for synthesizing and outputting the main screen image output from the image quality improving unit and the sub screen image output through the switching unit; An OSD unit for synthesizing OSD type data on an image screen output through the PIP mux; A color coordinate conversion unit for converting color coordinates of an image output from the OSD unit into color coordinates of a display device; A look-up table that compensates for the photoelectric transmission characteristics of the display device from the output of the color coordinate conversion unit; A synchronization waveform generator which generates a high-quality synchronization signal in accordance with a standard and outputs it to a digital display device together with an image signal; And a digital / analog converter configured to analogize the signal output from the sync waveform generator and output the analog signal to an analog display device. The method of claim 9, wherein the image quality improving unit Contour sharpening unit for sharpening the contour of the main screen image, The contour sharpening unit A first low pass filter for first-order low pass filtering the luminance signal of the input main picture image; A subtractor for outputting a difference signal between the input luminance signal and the first low pass filtered signal; A second low pass filter for performing second order low pass filtering on the difference signal output from the subtractor; A multiplier for multiplying the second low pass filtered signal by a constant α, And an adder configured to add an output of the multiplier and the input luminance signal to output the multiplier. The method of claim 9, wherein the color coordinate conversion unit A general purpose image processing apparatus for a digital TV monitor, characterized in that to perform color coordinate conversion using the following equation.

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