JP2002300537A - Video frequency converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent smoothness of a moving image from being lost when converting the frame frequency of a TV signal or a video. SOLUTION: For an image signal written in an image memory 2, the two field images continuously made adjacent on a time axis are read simultaneously, and the same field signals are rear twice repeatedly, and a skip scanning/ successive scanning converting part 4 composes the adjacent two skip scanning field signals for generating one successive scanning image, and interpolates the successive scanning image with the interpolation timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video frequency converter for converting a TV (television) signal or a frame frequency of a movie.

[0002]

2. Description of the Related Art FIG.
The figure shows a case where a TV signal of / 50 (second) and one frame is 1/25 (second) is converted into 1/30 (second). In this example, it is necessary to interpolate one for every five pre-conversion frames, so in the example shown in FIG. 4, the first field (odd line) 3a and the second field (even number) of the three frames Line 3b is interpolated.

[0003]

However, in the method of simply inserting the same image, there is a problem that the movement of the image is not smooth because the time that the same image continues is long. The converted image in the example shown in FIG. 4 has the same image continuing for (1/30) × 2 seconds. In addition, when the field frequency is simply converted without inserting or thinning out an image, a temporal change for overtaking or overtaking appears in the converted image, and in the case of the TV system conversion,
Since the difference in the field frequency is small, there is a drawback that the difference appears in the converted image for a long time.

In recent years, in order to solve this problem, there has been proposed a method of detecting a scene change of an image and thinning / inserting a scene so that the motion of the image becomes smooth. Is not always suitable for thinning / inserting a scene, and the memory overflows or underflows. Further, if thinning / insertion is performed at the maximum cycle resulting from the limitation of the memory capacity irrespective of the scene change, the smoothness of the moving image is lost.

The present invention has been made in view of the above-mentioned problems of the prior art, and
It is an object of the present invention to provide a video frequency conversion device capable of preventing loss of smoothness of a moving image when converting a signal or a frame frequency of a movie.

[0006]

According to the present invention, in order to achieve the above object, one field signal is used twice to convert a continuous two field signals into a frame signal of progressive scanning. Are interpolated.

That is, according to the present invention, means for writing two consecutive inter-scan field signals before conversion into a memory at the frequency of the field signal, and two continuous field signals at the frequency of the converted field signal from the memory. The means for simultaneously reading out the signals and the two field signals read out from the memory are compared, the still picture section outputs two continuous field signals as they are, and the moving picture section compares and computes the two continuous field signals. A video frequency conversion device comprising: means for generating correction data and converting it to a frame signal for progressive scanning; and means for interpolating a frame signal for progressive scanning at an interpolation timing according to a field frequency before conversion and a field frequency after conversion. Is done.

That is, according to the present invention, means for writing a frame signal of a progressive scan before conversion into a memory at the frequency of the frame signal, and converting the frame signal of the progressive scan from the memory into an odd number at a frequency of the converted frame signal. Means for dividing the line into even lines and simultaneously reading the same odd lines or even lines twice, and combining the odd lines and the even lines read from the memory to convert them into frame signals for sequential scanning In addition, there is provided a video frequency conversion apparatus having means for interpolating a frame signal of progressive scanning at an interpolation timing according to a field frequency before conversion and a field frequency after conversion.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a video frequency conversion device according to the present invention, FIG. 2 is an explanatory diagram showing processing when the video frequency conversion device of FIG. 1 converts a field frequency of a TV signal, and FIG. FIG. 2 is an explanatory diagram showing a process of converting the frame frequency of a movie by the video frequency conversion device in FIG.

With respect to the video frequency converter shown in FIG.
The case where the field frequency of the TV signal is converted will be described as an example. In FIG. 1, a write address generation circuit 1
Generates a write address based on the input synchronization signal S2 of the input image signal S1, and writes two consecutive fields adjacent to each other on the time axis of the interlaced scan input image signal (hereinafter also referred to as I image). The data is sequentially written to the image memory 2 according to the address. Further, the read address generation circuit 3 generates a read address based on the output synchronization signal S4 of the output image S3, and the image signal written in the image memory 2 is continuously read on the time axis by this read address. Two field images (read output 1 and read output 2) are read simultaneously.

These read outputs 1 and 2 are interlaced scans.
Applied to a progressive scan conversion unit (hereinafter, I → P conversion unit) 4,
The I → P converter 4 combines two adjacent field signals and converts them into a progressively scanned image (hereinafter also referred to as a P image). At this time, when the odd lines and the even lines of the first frame are combined, the P image is converted by combining the even lines of the same first frame and the odd lines of the next second frame.

The I-to-P converter 4 compares two adjacent field signals to detect whether it is a stationary area or a moving area. In the case of a stationary area, outputs the adjacent field signal as it is. In the case of, the most appropriate signal is calculated, generated and output from the continuous field signals depending on the nature of the moving image. Here, since the present invention relates to frequency conversion, I
→ There is no particular limitation on the method of interpolating the moving image part of the P conversion unit 4.

The output of the I → P conversion unit 4 is supplied to a scanning line conversion unit 5, where the I → P conversion unit 5 obtains a vertical scanning line required in accordance with the output image S3. The scanning line output from the conversion unit 4 is subjected to interpolation or thinning-out operation. The output of the scanning line converter 5 is supplied to the pixel converter 6, and the pixel converter 6 interpolates or thins out the pixels so as to obtain the required horizontal pixels according to the output image S3.

FIG. 2 shows, as an example, a field frequency = 5.
0 Hz, the number of scanning lines = 625, the interlaced scanning signal (625
/ 50I signal) is converted into an interlaced scanning signal (1125 / 60I signal) having a field frequency of 60 Hz and the number of scanning lines = 1125. In the present invention,
Two consecutive 625/5 of one 625 / 50I signal
The frame signal is interpolated from the 0I signal, and the
/ 60P signal, and the interpolated 625 / 60P signal is converted to a 1125 / 60I signal by scanning line conversion and horizontal pixel conversion.

Referring to FIG. 2 in detail, 625 / 50I
The input image signals of two fields adjacent to the signal are sequentially stored in the image memory 2 at 1/50 second per field in the order of odd field a → even field b → odd field a →.
Is written to. The image signal written in the image memory 2 includes an odd field 1a of the first frame, an even field 1b of the first frame, an even field 1b of the first frame, an odd field 2a of the second frame, and an odd field 2a of the second frame. And the even field 2b of the second frame, the even field 2b of the second frame, the odd field 3a of the third frame, and so on. Is read.

The I → P converter 4 adds these two continuous fields to generate a 1/60 second 625 / 60P image. At this time, if it is not the interpolation timing, the order is as follows: 1a + 1b → 1b + 2a → 2a + 2b → 2b + 3a. Then, when the interpolation timing comes, an interpolation frame of the same image as the previous frame = 2b + 3a is output.

Here, comparing the interpolated frames of the conventional example shown in FIGS. 2 and 4, the same image = 3a + 3b in the conventional example.
2 lasts for (1/30) × 2 seconds, whereas FIG.
The number of images = 2b + 3a (or the same image and the corrected image) lasts only half (1/60) × 2 seconds. Further, when viewed as a frame signal, the frame a and the frame b are combined with field signals at different times to become frame signals visually different in time, and become a converted image in which continuity of a moving image is maintained. This 625 /
Scan line conversion and horizontal pixel conversion of the 60P image
Convert to 60I signal.

FIG. 3 shows, as another operation example, a process of converting a frame frequency of a movie into a frame / field frequency of a TV signal. A signal of 24 frames / sec progressive scanning (24P signal) is written to the image memory 2 at this frequency, and at the time of reading, the odd lines and the even lines are divided at 60 frames / sec and simultaneously, the odd lines or the even lines. The line is repeatedly read twice. The processing of the I → P converter 4 is the same. Also in this case, the same two images = 1a + 1b, 3a + 3b (or the same image and the corrected image) last only (1/60) × 2 seconds.

[0019]

As described above, according to the present invention, 1
One field signal is used twice to detect and correct a moving image from two consecutive field signals, convert the signal into a progressive scanning frame signal, and further convert the progressive scanning frame signal into a vertical / vertical frame signal.
Since horizontal interpolation is performed, loss of smoothness of a moving image can be prevented when converting a TV signal, a frame frequency of a movie, or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a video frequency conversion device according to the present invention.

FIG. 2 is an explanatory diagram showing processing when the video frequency conversion device of FIG. 1 converts a field frequency of a TV signal.

FIG. 3 is an explanatory diagram illustrating a process in which the video frequency conversion device in FIG. 1 converts a frame frequency of a movie.

FIG. 4 is an explanatory diagram showing processing when a conventional video frequency conversion device converts a field frequency of a TV signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Write address generation circuit 2 Image memory 3 Read address generation circuit 4 Interlaced scanning → sequential scan conversion part 5 Scan line conversion part 6 Pixel conversion part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C063 BA01 BA04 BA08 BA09 BA10 CA01 CA05 CA07 5C082 AA02 BA27 BA41 BB15 BB25 BC03 BC19 CA55 CA81 CA84 CB01 DA54 DA55 MM10

Claims (3)

[Claims] 1. A means for writing two consecutive field signals before conversion of interlaced scanning into a memory at the frequency of the field signal, and means for simultaneously reading two continuous field signals from the memory at the frequency of the converted field signal. And the two field signals read from the memory are compared, the still image part outputs two continuous field signals as they are, and the moving image part compares two consecutive field signals and generates correction data. A video frequency conversion device comprising: means for converting into a frame signal for progressive scanning; and means for interpolating a frame signal for progressive scanning at an interpolation timing according to a pre-conversion field frequency and a post-conversion field frequency. 2. A means for writing a frame signal of a sequential scan before conversion into a memory at a frequency of the frame signal; and a step of converting the frame signal of the progressive scan from the memory into an odd line and an even line at a frequency of the converted frame signal. Means for dividing and simultaneously reading the same odd-numbered line or even-numbered line twice, and combining the odd-numbered line and the even-numbered line read from the memory to convert them into frame signals for sequential scanning;
Means for interpolating frame signals of progressive scanning at interpolation timings according to the pre-conversion field frequency and the post-conversion field frequency. 3. The video frequency converter according to claim 1, further comprising means for converting each frame signal of said progressive scanning into a field signal of interlaced scanning.