JP2006511121A - Method and apparatus for generating fine lines in a video image - Google Patents

Abstract

A method and apparatus for thinning lines in a video is a line signal (15) having a pair of spatially separated transitions (16) that are tilted towards each other and merge into a first thickness edge (17); The first thickness includes providing the line signal (15) of the video, which is the thickness of an edge that produces a line of a given width in the video. At least one or more transitions (16) in the center of the edge (17) to generate a new line signal (18) with a second thickness edge (19) less than the first thickness. Moving toward and reducing the width of the given line in the video.

Description

  The invention relates to video signal processing and, more particularly, to a method and apparatus for making fine lines thinner in a video image to create very thin lines or to produce a sharper video image.

  The perceived refinement of the displayed video image is generally achieved by one of two basic types of sharpness enhancement techniques or methods: peaking and image quality improvement (LTI). Has been achieved by processing the original video signal. The peaking method is a linear technique that selectively activates high frequencies within the image background without adding new high frequencies. This method creates undershoots and overshoots when providing line signals. These moderate amounts of undershoot and overshoot are extremely helpful in improving the sharpness of the picture object. However, if the amount of undershoot and overshoot is not well controlled, the image quality will deteriorate. Further, this method does not make the fine line thinner, and in practice, makes the fine line wider or thicker.

  The LTI method employs a higher degree of non-linear techniques that attempt to sharpen edges in video pictures without introducing the undershoot and overshoot introduced by the peaking method. As such, a truly new high frequency has been introduced into the displayed video image.

  FIG. 1 illustrates the operation of the LTI method. A solid line 10 indicates an original line signal, and a broken line 11 indicates an LTI processing (new line signal) line signal. As shown, the slope of the adjacent edge 12 and each turn 13 is such that it slopes in the new line signal 11. Therefore, this method often produces a pleasant image that makes the clear impression more intense. However, the increase in luminance at the vertex of the new line signal 11 becomes a line thickness T2 that is thicker than the line thickness T1 of the original line signal 10.

  Therefore, in order to produce a sharper video image, there is a need for a sharpening enhancement method that creates very thin lines in the video image or makes existing thin lines thinner.

  The effects, essence, and main additional features of the present invention are more fully considered in the embodiments described and illustrated in detail with reference to the drawings, in which symbols and the like are used to identify the elements, etc. Indicated.

  It should be understood that the drawings are for purposes of illustrating the concepts of the invention and are not to scale.

  A method and apparatus for thinning a line in a video provides a video line signal, the signal lines tilting towards each other and having a pair of transitions spaced between the ends of the first thickness, The first thickness at the end produces a line with the width given in the video. At least one of the transitions moves to the center of the end to reduce the width of the given line in the video to generate a new line signal with a second thickness edge that is less than the first thickness .

  The present invention is a method and apparatus for creating a fine line in a video image and / or making it thinner (becomes a very thin line) in a video image to produce a sharper video image. A “thin line” is defined as a very limited width, eg, a line, line segment, or curve that is a few pixels or less, or is defined based on application and personal preferences. Scanning across the edge is in spatial proximity to each other (in the order of several samples or pixels), for example, a black line to white transition followed by a white to black transition, Alternatively, two transitions are generated at the pixel luminance value level, such as a transition from black to gray followed by a transition from gray to white. The width of the transition is very limited, often on the order of 1 to 4 pixels.

  FIG. 2 replicates the original (thin) line signal processed in accordance with the present invention. A solid line 15 indicates the original line signal. According to the present invention, the direction of the center C of the edge 17 (in FIG. 2, this is the direction in which the luminance is increased) by positioning the turns so as to approach each other and by making the slope of each turn 16 steep. In the original line signal by shifting each transition 16 of the original line signal. This process generates a new line signal 18 (indicated by a broken line) having a line (edge 19) thickness T2 that is thinner than the line thickness T1 of the original line signal 15. Thus, fine lines and / or narrower fine lines are created that give the video image more sharpness.

  FIG. 3 is a block diagram of a fine line generator according to a first exemplary embodiment of the present invention. The thin line detector 20 performs a scan on the original line signal so that each video image is scanned for a line that meets the criteria described above (ie, a line, line segment, or curve of very limited width). A fine line detection signal is generated by executing a conventional fine line detection process. In one exemplary process, a thin line detection signal is generated only if both transitions are found close together. Of course, there are mainly other thin line detection processes used to generate the thin line detection signal.

  The original line signal is also modified signal generator to calculate a modified signal that is adapted to the original line signal (after sub-pixel shifting) to produce a thinner line than the line in the original video image 30 is used. The change signal generator 30 includes, for example, using a non-linear image quality correction function (LTI) algorithm. The tilt detection discriminator 40 identifies the tilt detected in the thin line detection signal or the angle of the detected line, that is, the vertical, horizontal, or any other tilt angle in the spatial domain, and generates a tilt detection signal. In one exemplary embodiment, the slope detection discriminator 40 has an edge direction that has the largest absolute change in pixel or sample value across the edge and the smallest absolute change in pixel or sample value along the edge. Search with respect to the line edge, as defined by the edge, in the main direction, for example, n angles at 10 degree intervals.

  The sub-pixel shifter 50 receives the change and slope detection signals and, for example, a selected amount of steepness that will be determined by a combination of user preferences and edge characteristics (direction and intensity) found in the slope direction signal. To shift the change signal onto the subpixel grid. The adder 60 combines the shifted change signal and the original line signal to produce the new line signal 17 of FIG. 2 with fine lines and / or narrower fine lines.

  FIG. 4 is a block diagram of a fine line generator according to a second exemplary embodiment of the present invention. In this embodiment, the original line signal is adapted to the peaking signal generator 300. The peaking signal generator 300 calculates a peaking signal from the original line signal. The peaking signal generator 300 may be implemented with a conventional high pass or band pass filter device, or a combination thereof. The thin line detector 200, which may be the same as the thin line detector described in the first embodiment of FIG. 3, uses a conventional thin line detection process on the original line signal to detect a thin line detection signal (detected). Line or thin line). The thin line type identifier 400 identifies the line tilt direction or angle detected in the thin line detection signal, ie, vertical, horizontal, or any other tilt angle in the spatial domain. This edge information is used by the gain factor determiner 500 to determine the gain factor. The amplifier 600 provides a fine line gain signal with a relatively low amplitude that is added or subtracted (depending on the sign of the gain factor) to the sum of the peaking signal and the original line signal at summer 700. The original line signal is amplified by the gain factor. The fine line gain signal offsets the peaking signal, either negatively or positively, each being either a finer bright line or a thinner darker line.

  This process is sometimes new because it "overcorrects" the original line signal, i.e., produces the desired sharp and steep transition with the desired intensity of "undershoot" and "overshoot". Alternatively, the “modified” line signal is further processed by a conventional media type filter 800 that clips a new line signal between two predefined clipping level limits 1 and 2. The predefined clipping level may be a sample value at the start of a transition and a sample value at the end of a transition. Media type filter 800 transmits a new line signal if its value is between limits 1 and 2. If the new line signal is not between limits 1 and 2, then either the limit 1 or limit 2 clipping level is selected (just three intermediate values).

  The second embodiment is simpler and cheaper to implement than the first embodiment because it eliminates the sub-pixel shift of the first embodiment. In addition, the second embodiment can also easily generate either a thin dark line or a thin bright line by simply adding or subtracting the peaking signal from the original line signal. The first embodiment also makes it easy to produce either a thin dark line or a thin bright line by shifting the modified signal outward.

  The method and apparatus of the present invention is a video / image storage device such as a television, set-top box, desktop, laptop or palmtop computer, personal digital assistant (PDA), video cassette recorder (VCR), digital It may be implemented in a system such as a video recorder (DVR), a TiVO device, etc., or a part or combination of these and other devices. Such a system may include one or more video / image resources, one or more input / output devices, a processor, and memory. Alternatively, the video / image resource means, for example, a television receiver, a VCR or other video / image storage device. The resources can be from a server or, for example, the Internet, a wide area network, a metropolitan area network, a local area network, a terrestrial broadcast system, a cable network, a satellite network, a wireless network, or a telephone network, and these and other types of networks Or one or more network connections for receiving video from multiple servers via a portion or combination.

  The input / output device, the processor, and the memory communicate via a communication medium. A communication medium may mean, for example, one or more internal connections of a bus, communication network, circuit, circuit card, or other device, as well as portions and combinations of these and other communication media. Input video data from the resource is processed according to one or more software programs and executed by the processor to generate an output video / image that is provided to the display device.

  In the preferred embodiment, the principles of the invention may be implemented by computer readable code executed by a system. The code may be stored in a memory as described above, or may be read / downloaded from a memory medium such as a CD-ROM or floppy disk. In other embodiments, the hardware circuitry may be used as a substitute for or in combination with software instructions for implementing the present invention. For example, the elements shown in FIGS. 3 and 4 may also be implemented as separate hardware elements.

  Although the invention has been described with reference to the above embodiments, major improvements and modifications can be made without departing from the spirit of the invention. Accordingly, such modifications and changes are considered within the scope of the appended claims.

It is a figure which shows the line signal processed by the conventional brightness | luminance transit improvement method with a graph. FIG. 3 is a graphical illustration of a line signal processed according to the principles of the present invention. 1 is a block diagram of a fine line generator / enhancement device according to a first exemplary embodiment of the present invention. FIG. FIG. 4 is a block diagram of a fine line generator / enhancement device according to a second exemplary embodiment of the present invention.

Claims (28)

A method of thinning lines in a video,
A line signal having a pair of spatially separated transitions that incline toward each other and merge into an edge of a first thickness, the first thickness being an edge that produces a line of a given width in the video Providing the line signal of the video, which is a thickness of
Moving at least one or more transitions toward the center of the edge to generate a new line signal having an edge of a second thickness less than the first thickness, and provided in the video To reduce the width of a given line. The moving procedure includes a procedure for calculating an adjustment signal from a line signal, and
The method of claim 1, further comprising combining the adjustment signal and the line signal to generate the new line signal. The moving procedure is:
Calculating a change signal from the line signal;
The method of claim 1, comprising combining the change signal and the line signal to generate the new line signal. The moving procedure is:
Calculating a change signal from the line signal;
Shifting the change signal according to a selected amount of steepness to generate a shifted change signal;
The method of claim 1, comprising combining the shifted change signal and the line signal to generate the new line signal. The moving procedure is:
Calculating a change signal from the line signal;
Detecting the line in the line signal;
A procedure for identifying an inclination angle of the detected line;
Shifting the change signal according to a selected amount of steepness determined by at least the identified tilt angle to generate a shifted change signal;
The method of claim 1, comprising combining the shifted change signal and the line signal to generate the new line signal. The moving procedure is:
Calculating a peaking signal from the line signal;
The method of claim 1, comprising combining the peaking signal and the line signal to generate the new line signal. The steps to move are
Calculating a peaking signal from the line signal;
A procedure for generating a fine wire gain signal;
The method of claim 1, further comprising combining the fine line gain signal, the peaking signal, and the original line signal to generate the new line signal. The generating procedure is as follows:
Detecting the line in the line signal;
A procedure for identifying an inclination angle of the detected line;
A procedure for determining a gain factor using the tilt angle;
The method of claim 7, further comprising: multiplying the line signal by the gain factor.   9. The method of claim 8, further comprising the step of clipping the new line signal between two predefined clipping levels.   8. The method of claim 7, further comprising the step of clipping the new line signal between two predefined clipping levels. A device for thinning lines in a video,
A line signal having a pair of spatially separated transitions that incline toward each other and merge into an edge of a first thickness, the first thickness being an edge that produces a line of a given width in the video Means for calculating an adjustment signal from the line signal having a thickness of
The adjustment signal and the line signal to move at least one or more transitions toward the center of the edge to generate a new line signal having an edge of a second thickness less than the first thickness; Means for reducing the width of a given line in the video.   The apparatus of claim 11, wherein the calculating means calculates a change signal having the adjustment signal.   13. The apparatus of claim 12, further comprising means for shifting the change signal before combining with the line signal. Means for detecting the line in the line signal;
Means for identifying an inclination angle of the detected line,
14. The apparatus of claim 13, wherein the means for shifting shifts the change signal according to a selected amount of steepness determined by at least the identified tilt angle.   The apparatus of claim 11, wherein the calculating means calculates a peaking signal having the adjustment signal. Means for generating a fine wire gain signal;
16. The apparatus of claim 15, further comprising means for combining the fine line gain signal, the peaking signal, and the line signal to generate the new line signal. The fine line gain signal generating means includes:
Means for detecting the line in the line signal;
Means for identifying an inclination angle of the detected line;
Means for determining a gain factor using the tilt angle;
17. The apparatus of claim 16, comprising means for multiplying the line signal and the gain factor to generate the fine line gain signal.   The apparatus of claim 17, further comprising means for clipping the new line signal between two predefined clipping levels.   17. The apparatus of claim 16, further comprising means for clipping the new line signal between two predefined clipping levels. A memory medium for thinning lines in a video,
A line signal having a pair of spatially separated transitions that incline toward each other and merge into an edge of a first thickness, the first thickness being an edge that produces a line of a given width in the video A code for calculating an adjustment signal from the line signal having a thickness of
The adjustment signal and the line signal to move at least one or more transitions toward the center of the edge to generate a new line signal having an edge of a second thickness less than the first thickness; A memory medium for reducing the width of a given line in the video.   21. The memory medium of claim 20, wherein the code for calculating the adjustment signal calculates a change signal having the adjustment signal.   The memory medium of claim 21, further comprising a code for shifting the change signal before combining with the line signal. A code for detecting a line in the line signal;
A code for identifying the detected line inclination angle;
23. The memory medium of claim 22, wherein the code for shifting the change signal shifts the change signal according to at least a selected amount of steepness determined by the identified tilt angle.   21. The memory medium of claim 20, wherein the code for calculating the adjustment signal calculates a peak signal having the adjustment signal. Code for generating a fine wire gain signal;
25. The memory medium of claim 24, further comprising code for combining the fine line gain signal, the peaking signal, and the line signal to generate the new line signal. The fine line gain signal is:
A code for detecting a line in the line signal;
A code for identifying an inclination angle of the detected line;
A code for determining a gain factor using the tilt angle;
26. The memory medium of claim 25, further comprising code for multiplying the line signal and the gain factor to generate the fine line gain signal.   27. The memory medium of claim 26, further comprising code for clipping the new line signal between two predefined clipping levels.   The memory medium of claim 25, further comprising code for clipping the new line signal between two predefined clipping levels.

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