JP2693515B2 - Image motion detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention is used for a device for correcting unnecessary movement of an image on a television screen due to parallel movement or vibration of an image pickup camera. The present invention relates to an image motion detection device.

(Prior Art) The movement of an image on a television screen includes movement of an object in the image and movement of a camera in parallel. The former is a local movement of the image, while the latter appears as a parallel movement phenomenon in which the entire image moves while maintaining the mutual relationship. Such parallel movement of the entire image is further divided into fine movements due to camera panning and camera vibrations, and such fine movements make the screen difficult to see. As described above, in order to improve unnecessary motion, a correction device has been developed which detects a motion vector indicating the direction and size 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 is translated in the direction of the arrow as shown in (a) to (b) to (c) of the figure, the motion vector (arrow) becomes horizontal and vertical as shown in FIG. Is given by the deviation (a, b) of. Therefore, by detecting this motion vector and using the information to shift the image of the current frame in the reverse direction by the size of the motion vector, the motion due to the parallel movement of the camera can be compensated.

By the way, in order to perform the above-described compensation, it is necessary to detect image motion. Conventional image motion detection methods
A representative point is set in the video signal one frame before (two fields before), and a correlation operation 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 of the representative point P in the area A1 of the video signal two fields before this,
A calculation is performed with a plurality of pixels in the area A3 of the third field, 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 movement direction. And
By setting a plurality of such areas, the motion vector information obtained in each area is classified by the vector information indicating the same direction, and the direction and size indicated by the most collected vector information are displayed on the entire screen. The final motion vector information is obtained as the translation direction and amount of the.

(Problem to be Solved by the Invention) According to the above-described conventional motion vector detecting method, it is not possible to detect motion vector information between fields because of the correlation calculation between frames. That is, for example, when the camera moves in parallel when moving from the first field to the second field and the camera moves in parallel in the third field such that the camera moves back to the original position, the detection cannot be performed. This means that the accuracy of correcting the parallel movement of the image using the motion vector information is poor.

Therefore, it is an object of the present invention to provide an image motion detecting device which can detect even a motion between fields and is effective for improving the accuracy of image motion correction.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, first, a vertical interpolating means interpolates between lines of an interlaced video signal to generate a video signal interpolated in the vertical direction. As a result, pixels can be obtained at corresponding positions even between fields. Next, the representative point selection and output means divides the vertically interpolated video signal output from the vertical interpolation means into a plurality of predetermined areas for each field, and each divided area corresponds to a predetermined representative point. Only a plurality of pixel signals are extracted and delayed and output so as to be synchronized with the next field. Then, the representative point signal of each divided area outputted from the representative point selecting and outputting means and the vertically interpolated video signal of the next field from the vertical interpolating means are inputted to the correlation calculating means, and each representative point signal and this Correlation calculation is performed between the vertical direction interpolated video signal corresponding to and the signal in each divided area to obtain motion vector information for each divided area. Further, the motion vector information of each divided area obtained from the correlation calculating means is input to the motion vector information determining and outputting means, the most vector information indicating the common motion direction is determined, and the direction by this vector is finally determined. It is configured to be output as motion vector information.

(Operation) Even when 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 the fields by the above means, the pixels corresponding to the vertical direction exist between the fields. Motion vector information between fields can be accurately detected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The input terminal 10 is supplied with a digitized interlaced video signal captured by a camera. This video signal is supplied to the vertical interpolation circuit 11 and converted into a vertical interpolation video signal.
This vertically interpolated video signal is supplied to the latch circuit 12 and the correlator 17
Supplied to

The latch circuit 12 latches the image information of the representative point of each area previously divided in the field of the vertically interpolated video signal at the timing of the latch pulse T1. The image information of the representative point is transferred to the representative point storage field memory 13 by the transfer pulse T2 and stored in 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 includes a write address generated from the address controller 14 in the write mode, and an address in the read mode. A read address generated from the controller 14 is supplied via an 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 supplied to the correlator 17.

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
Is controlled by the latch pulse T3 so as to hold the image information of each representative point from the representative point storage field memory 13 in association with each representative point extraction area of the vertical interpolation video signal of the current field.

The correlator 17 performs a correlation operation between the image information of the representative point one field before held in the latch circuit 16 and each pixel in the area of the current field corresponding to the area of the representative point image information. The result of the correlation operation of each representative point input to the adder 18 is cumulatively added. The result of the accumulation is input to the motion vector generation circuit 19. Motion vector generation circuit 19
Is the largest motion vector among the motion vector addition results indicating the respective directions, that is, the final motion vector is determined, in which the direction of the motion vector is determined as the parallel movement direction of the entire screen. The information is output to the output unit 20.

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 supplied to the line memory DL1 and the coefficient unit K1 via the input terminal 10. The line memory DL1 has a delay amount of one line and supplies its output to a similar series circuit of the line memories DL2 and DL3.
The outputs of the line memories DL1, DL2, DL3 are also supplied to coefficient units K2, K3, K4, respectively. The coefficient values of the coefficient units K1 to K4 can be controlled by the coefficient generator 111. Coefficient units K1 and K
The output of 2 is input to the adder 112, and the outputs of the coefficient units K3 and K4 are input to the adder 113. Then, the outputs of the adders 112 and 113 are added by the adder 114 and are derived as a vertical interpolation video signal.

The vertical interpolation circuit 11 can obtain interpolated signals between lines by using the signals of four lines. Now, the interlaced video signal is shown in a non-interlaced form in which lines of odd fields and even fields are overlapped.
This is as shown in FIGS. In the figure, n1 to n10
Is a scanning line, and P1 to P10 indicate luminance (pixel) levels.

When obtaining a vertical direction interpolation signal, an interpolation signal corresponding to a line position of an even field is created using a signal of an odd field, for example. That is, the interpolation signal shown in FIG.
P2 ', P4', P6 ', P8' ... Are created using the lines of the first field. Next, when the video signal of the even field is input, the coefficients of the coefficient units K1 to K4 are switched and each line signal is taken out in the form of a filter as shown in FIG. In this way, for the line signal of the odd field, the interpolation signal of the position corresponding to the line position of the next even field is created, and for the line signal of the even field, the characteristics are switched by passing through the interpolation filter and almost the original signal is obtained. By deriving the signal as a signal close to, motion vector information can be obtained by performing correlation calculation between fields. Even if the correlation operation is simply performed between the line signal of the odd field and the line signal of the even field of the interlaced video signal, the correlation calculation result is incorrect because there is no line corresponding to the vertical position. Although motion vector information is shown, a motion vector for each field can be obtained by generating an interpolation signal for each field and performing a correlation operation as in this embodiment.

Next, the principle of determining the final motion vector information of the entire screen using the motion vector information obtained by performing the correlation operation will be further described.

As shown in FIG. 7, the video signal of one field is divided into M in the horizontal direction and N in the vertical direction in the memory space.
It is divided into (M × N) areas. Then, a pixel serving as a reference point (x mark) is selected for each region, and this is set as a representative point.
By detecting how much the pixel of the representative point has moved in the direction of each field by comparing the signal levels, a motion vector can be obtained for each area. Next, among the motion vectors detected for each area, the motion vector with the largest number is determined as the motion vector of 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 region will be described.

As shown in FIG. 8, one area has (m × n) pixels. The luminance signal level (10) of the pixel (p) at the representative point in a certain field is stored in the memory 13
It was stored in. Then, as shown in FIG. 8 (b), the luminance signal levels of all pixels in the next field are 11,
Suppose it was 12, 13 ... 1 mn. In this case, the following operation is performed on the luminance signal level 10 of the previous field and the luminance signal level of each pixel of the current field.

10-11 10-12 10-13 10-1nm As a result, it is assumed that the pixels whose signal levels are equal and the calculation result is zero are, for example, the pixels (a1, a2, a3) at three places in the figure. Then, in this area, each vector connecting the representative point (p) and each pixel (a1, a2, a3) is determined as the motion vector b1, b2, b3, respectively.

As described above, in one area, a plurality of motion vectors are detected, and a motion vector relating 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 region, and the direction and the size of the motion vector in which the sum of the addition results is the largest value is determined for the entire screen. The moving direction and the moving amount are determined. In other words, the most detected vector is determined as the final motion vector through each region.

In the above description, when the motion vector is first detected, it is assumed that the motion vector is detected from all the areas. However, the area used for the motion detection in the area shown in FIG. It may be possible to select from the outside. In this case, the operation timing signal given to the correlator 17 may be adjusted by the address controller 14. By doing so, in a region where it is difficult to detect a motion, for example, a region where a white wall is imaged or a region where a clear sky is imaged, the useless calculation as described in FIG. 8 can be eliminated. You can

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain an image motion detection device which is capable of detecting a motion between fields and which is effective in improving the accuracy of image motion correction. You can

[Brief description of the drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing a concrete example of the vertical interpolation circuit of FIG. 1, and FIGS. 3 and 4 are diagrams for explaining the structure of an interlaced video signal. 5 and 6 are explanatory diagrams for explaining the structure of the vertically interpolated video signal obtained by vertical interpolation, and FIGS. 7 and 8 are correlation diagrams. FIG. 9 is an explanatory view for explaining the region and the process of determining the motion vector, FIG. 9 is an explanatory view for explaining the parallel movement of the entire image by camera imaging, and FIG. 10 is a vector explanatory view of the parallel movement of the entire image, FIG. 11 is an explanatory diagram shown for explaining a conventional motion detection method by correlation calculation. 11 ... Vertical interpolation circuit, 12, 16 ... Latch circuit, 13 ... Representative point storage memory, 14 ... Address controller, 15 ...
Address switching circuit, 17 ... Correlator, 18 ... Cumulative adder, 19 ... Motion vector generation circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsuneharu Yasuda 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Center (72) Inventor Masayuki Fukuda 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Inside the Broadcasting Corporation Broadcasting Center (72) Inventor Yoshihide Kawamura 1 Kosuka Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Komukai Factory (72) Inventor Minoru Abe 1 Kosuka-Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Address: Komukai Plant, Toshiba Corporation (72) Inventor: Hideyuki Shimada 1 Tokoba, Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture (56) Reference: JP-A-63-166370 (JP, A)

Claims (1)

(57) [Claims] 1. A vertical interpolating means for supplying an interlaced video signal, interpolating between lines of the video signal to generate and outputting a video signal interpolated in a vertical direction, and output from the vertical interpolating means. Representative point selection and output means for extracting only a plurality of pixel signals corresponding to respective representative points of a plurality of predetermined divided areas for each field from the vertically interpolated video signal and delaying and outputting the pixel signals in synchronization with the next field. The representative point signal of each divided area outputted from the representative point selecting and outputting means and the vertically interpolated video signal of the next field from the vertical interpolating means are supplied, and each representative point signal and its corresponding vertical direction Correlation calculation means for obtaining motion vector information for each divided area by performing correlation calculation with the signals in each divided area of the interpolated video signal, and for obtaining from this correlation calculation means Motion vector information of each of the divided regions is supplied, and a motion vector information determining and outputting unit that determines the most vector information indicating a common motion direction and outputs the direction based on this vector as final motion vector information is provided. An image motion detection device characterized by the above.