JPH0279584A - image motion detection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention is used in a device that corrects unnecessary movement of an image on a television screen due to parallel movement or vibration of an imaging camera. The present invention relates to an image motion detection device.

(Prior Art) Movement of an image on a television screen can be caused by movement of an object in the image or by parallel movement of a camera. The former is a local movement of the image, whereas the latter is a parallel movement phenomenon in which the entire image moves while maintaining its mutual relationship. Such parallel movement of the entire image further becomes a force surface. In order to correct such unnecessary motion, a correction device has been developed that detects a motion vector indicating the direction and magnitude of the motion and corrects the motion of the entire image.

FIG. 9 shows the principle of the correction device. If the image on the screen moves in parallel in the direction of the arrow as shown in (a) to (b) to (C) in the same figure, the motion vector (arrow) will move in the horizontal and vertical directions as shown in Figure 10. is given by the deviation (a, b) of Therefore, by detecting this motion vector and using that information to shift the image of the current frame in the opposite direction by the magnitude of the motion vector, it is possible to compensate for the motion caused by the parallel movement of the camera.

Incidentally, in order to perform the above compensation, image movement must be detected. The conventional image motion detection method is 1
A representative point is set in the video signal of the previous frame (two fields before), and a correlation calculation is performed with the current video signal to obtain motion vector information.

That is, as shown in FIG. 11, for example, if the third field is the video signal of the current field, the pixel at the representative point P in the area At of the video signal two fields before this and the area of the third field. A calculation is performed with a plurality of pixels of A3, a pixel having the same content as the pixel of the representative point P is detected, and the direction of the detected pixel is determined as the direction of movement. Then, by setting a plurality of such regions, classifying the motion vector information obtained in each region into vector information indicating the same direction, and determining the direction and magnitude indicated by the most collected vector information. The final motion vector information is obtained as the direction and amount of translation of the entire screen.

(Problems to be Solved by the Invention) According to the conventional motion vector detection method described above, since the correlation calculation is performed between frames, motion vector information between fields cannot be detected. That is, for example, in the case where there is a parallel movement of the camera when moving from the first field to the second field, and the camera is moved back in parallel in the third field, this cannot be detected. This means that the accuracy of correcting the translation of an image using motion vector information is poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image motion detection device that can detect even if there is a motion between fields and is effective in improving the accuracy of image motion correction.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, a vertical interpolation means first performs interpolation between lines of an interlaced video signal to obtain a vertically interpolated video signal. This makes it possible to obtain pixels at corresponding positions even between fields. Next, the representative point storage means divides one field of the vertically interpolated video signal from the vertical interpolation means into a plurality of regions, stores the signal corresponding to the representative point of each region, and stores the signal corresponding to the representative point of each region. Using each representative point signal and the vertical interpolation video signal from the vertical interpolation means, the correlation calculation means performs a correlation calculation between each representative point and the signal of each region of the vertical interpolation video signal corresponding thereto. Obtain multiple pieces of motion vector information in a region, use the motion vector information for each region obtained from this correlation calculation means to determine the most common vector information indicating a common motion direction, and finally determine the direction based on this vector. It is configured so that it can be obtained as motion vector information.

(Function) With the above means, even if the correlation calculation between the vertically interpolated video signal and the signal of the representative point of the representative point storage means is performed between fields, pixels corresponding to the vertical direction exist between fields. Motion vector information between fields can be detected accurately.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. An interlaced video signal captured by a camera and digitized is supplied to the input terminal 10 . This video signal is supplied to a vertical interpolation circuit 11 and converted into a vertically interpolated video signal. This vertically interpolated video signal is sent to a latch circuit 12 and a correlator 1.
7.

A latch circuit] 2 latches image information of a representative point of each region divided in advance within a field of a vertically interpolated video signal at the timing of a latch pulse T1. The image information of this representative point is transferred to the representative point storage field memory 13 by the transfer pulse T2, and is stored at a predetermined address for the representative point.

The representative point storage field memory 13 is controlled by a write/read mode switching signal W/R, and its address input is connected to the address controller 1 in the write mode.
The write at1nos generated from the address controller 14 and the read address generated from the address controller 14 in the read mode are respectively supplied via the address switching circuit 15. The image information of the representative point in the representative point storage field memory 13 is latched by the latch circuit 16 and sent to the correlator 1.
7.

The correlator 17 performs a correlation calculation between the vertically interpolated video signal from the vertical interpolation circuit 11 and the image information of the representative point latched by the latch circuit 16.

Here, the latch circuit 16 uses a latch pulse T3 to hold the image information of each representative point from the representative point storage field memory 13 in correspondence with each representative point extraction area of the vertically interpolated video signal of the current field. controlled.

The correlator 17 performs a correlation calculation between the image information of the representative point of the previous field held in the latch circuit 16 and each pixel in the area of the current field corresponding to the area of this representative point image information, and calculates the cumulative The correlation calculation results of each representative point manually entered into the adder 18 are cumulatively added. This cumulative addition result is input to one motion vector generation circuit. One motion vector generation circuit determines the largest addition result, that is, the addition result with the largest number of motion vectors, among the addition results of motion vectors indicating each direction, and determines the direction of the motion vector as the parallel movement direction of the entire screen. The output unit 2 outputs the final motion vector information.
Output to 0.

This embodiment is constructed as described above. Next, a specific example of the vertical interpolation circuit 11 will be described with reference to FIG.

The interlaced video signal is fed 1 to 1 to the line memory DL1 and the coefficient multiplier via the input terminal 10. The line memory DLL has a delay amount for one line,
The output is supplied to a series circuit of similar line memories DL2 and DL3. Each line memory DL1, DL2, DL3
The outputs of are also supplied to coefficient multipliers 2, K3, and K4, respectively. Coefficient values from 1 to 4 are sent to the coefficient generator 1.
11. The outputs of coefficient multipliers Kl and 2 are input to an adder 112, and the outputs of coefficient multipliers 3 and 4 are input to an adder 113. and adders 112 and 11
The outputs of 3 are added by an adder 114 and are derived as a vertically interpolated video signal.

The vertical interpolation circuit 11 described above can obtain interpolation signals between lines using signals of four lines. Now, if we represent an interlaced video signal in the form of a non-interlaced signal in which lines of odd and even fields are overlapped, the third
The result is as shown in FIG. In the figure, nl to n
lO is a scanning line, and P1 to PIO indicate brightness (pixel) levels.

When obtaining a vertical interpolation signal, for example, an interpolation signal corresponding to a line position of an even field is created using a signal of an odd field. That is, the interpolated signal P shown in FIG.
2-1P4-1P6-1P8-... were created using the lines of the first field. Next, when an even field video signal is input, the coefficient unit will be set to 1 to 4.
The coefficients are switched, and each line signal is extracted through a filter as shown in FIG. In this way, for the odd field line signal, an interpolated signal is created at a position corresponding to the next even field line position, and for the even field line signal, it is passed through an interpolation filter and its characteristics are switched to create an almost original f3 signal. By deriving a signal close to the signal, motion vector information can be obtained by performing a correlation calculation between fields. Even if you try to perform a correlation calculation between the odd field line signal and the even field line signal of an interlaced video signal, the correlation calculation result will be incorrect because there is no line corresponding to the vertical position. Although the motion vector information is inaccurate, if an interpolation signal for each field is created and a correlation calculation is performed as in this embodiment, a motion vector for each field can be obtained.

Next, the principle of determining the final motion vector information for the entire screen using the motion vector information resulting from the correlation calculation will be further explained.

As shown in FIG. 7, one field of video signal is divided into M horizontally and N vertically in the memory space.
Divide into XN) areas. Then, a pixel (marked with an "X") serving as a reference point is selected for each area, and this is used as a representative point. By detecting how much the pixel at this representative point has moved in the degree direction for each field by comparing signal levels, a motion vector can be obtained for each region. Next, among the motion vectors detected for each region, the motion vector with the largest number is determined as the motion vector for the entire television screen. This determination is performed by the motion vector generation circuit 19 shown in FIG.

Next, the principle of detecting a motion vector in one area will be explained.

As shown in FIG. 8, it is assumed that one region has (mXn) pixels. Here, the luminance signal level (lO) of the pixel (p) at the representative point in a certain field is determined by the memory 13.
Suppose that it is stored in Then, the luminance signal level of all pixels in the next field is 11 as shown in FIG. 8(b).
．． 12., 13, . . .lllIn. In this case, the following calculation is performed using the luminance signal level lO of the previous field and the luminance signal level of each pixel in the current field.

10-1nIIl As a result, the pixels where both signal levels are equal and the calculation result is zero are, for example, the three pixels (at.

a2, a3). Then, in this area,
Vectors connecting the representative point (p) and each pixel (at, a2, a3) are determined as motion vectors bt, b2, b3, respectively.

In this way, a plurality of motion vectors are detected in one region, and the motion vector related to the translation of the entire image cannot be uniquely determined. Therefore, in this embodiment, the number of motion vectors in the same direction and the same size is added through each area, and the direction and size of the motion vector that has the largest sum of the addition results is calculated for the entire screen. This is determined as the direction of movement and amount of movement. In other words, the vector detected most frequently in each region is determined as the final motion vector.

In the above explanation, when first detecting a motion vector,
Although the description has been made assuming that detection is performed from all areas, the area to be adopted for motion detection among the areas shown in FIG. 7 may be arbitrarily selected from the outside depending on the image content or the like. In this case, the calculation timing signal given to the correlator 17 may be adjusted by the address controller 14. In this way, in order to detect movement (for example, in an area where a pure white wall is imaged or an area where a clear sky is imaged, unnecessary calculations such as those explained in Fig. 8) can be performed. It can be eliminated.

[Effects of the Invention] As explained above, according to the present invention, an image motion detection device is obtained that can detect even if there is a motion between fields and is effective in improving the accuracy of image motion correction. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing a specific example of the vertical interpolation circuit shown in FIG. 1, and FIGS. 3 and 4 explain the structure of an interlaced video signal. 5 and 6 are explanatory diagrams shown to explain the structure of a vertically interpolated video signal obtained by vertical interpolation, and FIGS. 7 and 8 are diagrams showing correlation calculations. FIG. 9 is an explanatory diagram for explaining the process of determining regions and motion vectors. FIG. 9 is a μ explanatory diagram for explaining parallel movement of the entire image captured by a camera. FIG. 10 is a flat diagram of the entire image. FIG. 11, a vector explanatory diagram of line movement, is an explanatory diagram shown to explain a conventional motion detection method using correlation calculation. 11...Vertical interpolation circuit, 12.16...Latch circuit, 13...Representative point storage memory, 14...Address controller!・Roller, 15... Address switching circuit, 17.
...Correlator, 18...Accumulative adder, 1...Motion vector generation circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] Vertical interpolation means to which an interlaced video signal is supplied, generates an interpolation signal between lines of the video signal and outputs a vertically interpolated video signal, and a vertically interpolated video signal from the vertical interpolation means. representative point storage means for dividing one field into a plurality of regions and storing signals corresponding to the representative points of each region; each representative point signal from the representative point storage means; and vertical direction input from the vertical interpolation means. Correlation calculation means to which an interpolated video signal is supplied, performs a correlation calculation between signals of each region of the vertically interpolated video signal corresponding to each representative point, and obtains a plurality of pieces of motion vector information in each region; Motion vector generation means is provided with motion vector information for each area obtained from the calculation means, determines the most common vector information indicating a common motion direction, and obtains the direction based on this vector as final motion vector information. An image motion detection device characterized by: