JP2006215657A - Method, apparatus, program and program storage medium for detecting motion vector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect a motion vector of a subject with a minimized operation frequency by correcting an initial displacement vector based on overall motion characteristics of an extracted screen. <P>SOLUTION: Motion vectors of a plurality of blocks located in the vicinity of a detecting object block in a current field are read from a vector memory 4 as a first candidate vector group, and a logic motion vector arithmetic part 3 determines, based on a camera parameter including the direction of a camera in photographing, coordinate changes on the screen as second candidate vectors with respect to each detecting object block or with respect to a predetermined specified block. An initial displacement vector part 5 selects a motion vector with a value most suitable to the motion of the detecting object block of the current field as an initial displacement vector from the second candidate vectors and the first candidate vector group, and a motion vector arithmetic part 7 determines a motion vector of the detecting object block with the initial displacement vector as a start point through one or more operations. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motion vector detection method, a motion vector detection device, a motion vector detection program, and a program recording medium for moving image signals, and more particularly, for example, a television system conversion device that performs video signal conversion between different television systems. The present invention also relates to a motion vector detection method, a motion vector detection device, a motion vector detection program, and a program recording medium that can be suitably applied to a high-efficiency encoding device for image transmission.

  A technique for detecting a motion region in a moving image signal as a motion vector and performing motion correction using the motion vector, for example, when improving the inter-frame coding efficiency in high-efficiency coding at the time of image transmission, or It is particularly effective for reducing motion discontinuity due to field number conversion during television system conversion. For example, as a television system conversion device, Japanese Patent Application Laid-Open No. 01-309597 disclosed in Japanese Patent Application Laid-Open No. 01-309597 “Television Standard System Conversion Device” and Japanese Patent Application Laid-Open No. 03-280681 disclosed in Japanese Patent Application Laid-Open No. 03-280681 disclosed a motion using motion vectors. "Interpolation method", Journal of the Television Society shown in Non-Patent Document 1 (Vol. 45, No. 12, pages 1534 to 1543, published in 1991), or the National Convention of Television Society shown in Non-Patent Document 2 The technology described in the proceedings of the book (20-5, held in 1989) is proposed.

  Conventionally, as a motion vector detection method used in the television system conversion device described in each of the above-mentioned documents, for example, Japanese Patent Application Laid-Open No. 55-162683 shown in Patent Document 3 “Television Image Motion Detection Method” ”And Japanese Patent Laid-Open No. 55-162684 shown in“ Patent Document 4 ”,“ Detective Method for Asymptotic Detection of Image Motion Vectors ”, or Japanese Patent Laid-Open No. 60-158786 shown in Patent Document 5. Detection methods using the iterative gradient method described in “Image Motion Amount Detection Method” and Japanese Patent Application Laid-Open No. 62-206980 “Initial Deviation Method in Motion Estimation of Moving Image” shown in Patent Document 6 have been proposed. .

  In particular, the latter motion vector detection method based on the iterative gradient method is smaller and more accurate than the pattern matching method, and can detect a motion vector. That is, the motion vector detection method based on the iterative gradient method has a predetermined predetermined size of m × n pixels including, for example, m pixels in the horizontal direction and n lines in the vertical direction, for each field of the digitized television signal. By subdividing into blocks, each block is subjected to repetitive gradient calculation based on the signal gradient in the screen and the physical correspondence of the signal difference value between the corresponding screens The amount of motion was estimated.

  In this case, in Japanese Patent Application Laid-Open No. 62-206980 of Patent Document 6, detection is already made in a plurality of peripheral blocks including a block corresponding to the detected block as an initial value when estimating the motion amount. By selecting an optimal motion vector detection target motion vector detection vector from among motion vector candidates as an initial displacement vector, and starting calculation from a value close to the true motion vector of the detected block For example, a technique has been proposed in which the number of computations of the gradient method computation is reduced and, for example, a true motion vector is detected by two gradient computations.

  Japanese Patent Laid-Open No. 06-217266 “Motion Vector Detection Circuit” shown in Patent Document 7 discloses that at least between one block of image signals separated by at least one field or one frame in order to further improve the accuracy of motion vector detection. A method for detecting an initial displacement vector of motion has also been proposed.

On the other hand, if the moving image signal is a digital video or the like, the additional data can be transmitted simultaneously with the moving image data as a video stream. In the standards such as MPEG7 and MPEG21, the additional data In addition, it is configured such that camera parameters including information at the time of shooting related to camera operation such as camera orientation and zoom can be set. If the camera parameters are used, the motion vector of the screen resulting from the operation of the camera can be calculated theoretically. Japanese Patent Application Laid-Open No. 11-41500 “Motion vector detection apparatus and method and recording medium” disclosed in Patent Document 8 describes a method of calculating a motion vector of the entire screen from the camera parameters.
Japanese Laid-Open Patent Publication No. 01-309597 Japanese Patent Laid-Open No. 03-280681 Japanese Unexamined Patent Publication No. 55-162683 Japanese Patent Laid-Open No. 55-162684 JP 60-158786 A Japanese Patent Laid-Open No. 62-206980 Japanese Patent Laid-Open No. 06-217266 Japanese Patent Laid-Open No. 11-41500 The Journal of the Institute of Television Engineers of Japan (Vol. 45, No. 12, pages 1534 to 1543, published in 1991) Proceedings of the annual conference of the Institute of Television Engineers of Japan (20-5, 1989)

  However, in the conventional technique described above, when selecting an initial displacement vector from among a plurality of candidate vectors extracted from already detected motion vectors, each block is processed individually, and the initial displacement is performed with a small block. In order to select a vector, when the entire screen is moved by camera operation such as panning, tilting, zooming, etc. It is difficult to estimate, and as a result, the detection accuracy of the initial displacement vector may be lowered.

In the above-described region, a correct motion vector may not exist before one field, and a correct motion vector may not be detected over several fields.
In other words, in the above-described prior art, the initial displacement vector is calculated using only the luminance information of the screen without taking into consideration the change in the motion of the entire moving image due to the operation of the camera. There was a drawback of misdetecting.

  In addition, for a technique for obtaining a motion vector using a camera parameter as described in Japanese Patent Application Laid-Open No. 11-41500 “Motion vector detection apparatus and method and recording medium” disclosed in Patent Document 8, the camera indicated by the camera parameter This technique is limited to calculating motion vectors by operation. That is, a motion vector related to the entire shooting screen moving in conjunction with the camera operation is calculated, and processing for calculating a true motion vector related to a moving object independently of the camera operation is not taken into consideration. In addition, there is a possibility that the motion vector accuracy may be reduced when the camera parameter includes an error only by the motion vector calculation using the camera parameter.

  The present invention has been made to solve the above-described problems, and calculates initial displacement vector candidates of a moving object using camera parameters including information associated with camera operations such as camera orientation and zoom. Then, by further adding to the candidate vector group of initial displacement vectors using the motion vector of the moving object at least one field before, the selection width of the initial displacement vector is increased, and erroneous detection of the initial displacement vector is prevented, An object of the present invention is to provide a technique that can correctly detect a motion vector for each block including a moving object with a small number of calculations.

  The first technical means divides a field of a moving image signal into a plurality of blocks having a predetermined size, and each of the divided blocks has a motion between at least one field apart. In a motion vector detection method of a motion image signal for detecting a motion vector representing a magnitude and direction, the camera parameter is selected from the motion image signal to which camera parameters including information on the camera orientation and zoom at the time of shooting are added. A camera parameter acquisition step to acquire, a theoretical motion vector calculation step to calculate a coordinate change on the screen as a theoretical motion vector based on the camera parameter acquired by the camera parameter acquisition step, and a motion detected for each block A storage step for accumulating vectors for at least one field; The motion vectors of a plurality of blocks located in the vicinity of the detected block are read out from the motion vectors accumulated by the operation as a first candidate vector group for selecting an initial displacement vector of the detected block. Among the candidate vectors and the second candidate vector that is the theoretical motion vector calculated in the theoretical motion vector calculation step, the motion vector having the value most suitable for the motion of the detected block is determined as the initial displacement of the detected block. An initial displacement vector selection step for selecting as a vector, and performing one or more operations starting from the initial displacement vector selected in the initial displacement vector selection step to obtain and output a motion vector of the detected block; The calculated motion vector is used to calculate the motion vector of the moving image signal after the next field. Characterized in that it has a motion vector calculation step of storing by the storing step in order.

  A second technical means is the motion vector detection method according to the first technical means, wherein the theoretical motion vector calculation step calculates the theoretical motion vector for every detected block for all the blocks in the screen. Or the entire screen is divided into a plurality of predetermined areas, and the theoretical motion vector is calculated only for a predetermined specific block existing in each area. It is characterized in that it is used as a theoretical motion vector for each block in the area where each specific block exists.

  The third technical means divides a field of a moving image signal into a plurality of blocks having a predetermined size, and moves each moving block between moving image signals separated by at least one field. In a motion vector signal motion vector detecting apparatus for detecting a motion vector representing a magnitude and direction, the camera parameter is selected from among the motion image signals to which camera parameters including information on the camera orientation and zoom at the time of shooting are added. Camera parameter acquisition means for acquiring, theoretical motion vector calculation means for calculating a coordinate change on the screen as a theoretical motion vector based on the camera parameters acquired by the camera parameter acquisition means, and motion detected for each block Storage means for storing vectors for at least one field, and storage by the storage means The motion vectors of a plurality of blocks located in the vicinity of the detected block among the motion vectors are read out as a first candidate vector group for selecting an initial displacement vector of the detected block, and the first candidate vector group and the An initial displacement that selects a motion vector having a value most suitable for the motion of the detected block as an initial displacement vector of the detected block from the second candidate vectors that are the theoretical motion vectors calculated by the theoretical motion vector calculating means. A vector selection means, and the initial displacement vector selected by the initial displacement vector selection means is used as a starting point to perform one or more calculations to obtain and output a motion vector of the detected block. Accumulated by the storage means for calculating a motion vector of a moving image signal after the next field Characterized in that it comprises a vector computing means can, a.

  A fourth technical means is the motion vector detecting device according to the third technical means, wherein the theoretical motion vector calculating means calculates the theoretical motion vector for every detected block for all the blocks in the screen. Or the entire screen is divided into a plurality of predetermined areas, and the theoretical motion vector is calculated only for a predetermined specific block existing in each area. It is characterized in that it is used as a theoretical motion vector for each block in the area where each specific block exists.

  A fifth technical means is characterized in that the motion vector detection method described in the second or second technical means is a motion vector detection program realized as a program executable by a computer.

  A sixth technical means is a program recording medium in which the motion vector detection program described in the fifth technical means is recorded on a computer-readable recording medium.

According to the motion vector detection method, the motion vector detection device, the motion vector detection program, and the program recording medium according to the present invention composed of the technical means as described above, the following effects can be obtained.
When an initial displacement vector is selected from the detected motion vectors and a motion vector is detected using the initial displacement vector, in addition to the detected motion vector, the motion vector assumed by the camera parameter is also the initial displacement. Since it is added as a vector candidate, the opportunity to select the correct initial displacement vector can be expanded.

  As a result, even for moving images with very little shading on the screen, it is possible to select a more correct initial displacement vector without being affected by changes caused by camera operations such as panning, tilting, and zooming. In addition, erroneous detection of the initial displacement vector can be reduced, and the motion vector detection accuracy can be greatly improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for implementing a motion vector detection method, a motion vector detection device, a motion vector detection program, and a program recording medium according to the present invention will be described with reference to the drawings. In the following description, an example of an embodiment related to a motion vector detection device according to the present invention will be described, and description of an embodiment related to a motion vector detection method, a motion vector detection program, and a program recording medium according to the present invention will be omitted. From the following detailed description of the motion vector detection device, a motion vector detection method applicable to the motion vector detection device, a vector detection program for executing the motion vector detection method as a program by a computer, and the vector detection program It is also possible to easily understand a program recording medium for recording the program on a computer-readable recording medium.

First, an embodiment of a motion vector detection apparatus according to the present invention for detecting a motion vector of a moving image signal will be described in detail with reference to FIG. FIG. 1 is a functional block configuration diagram illustrating an example of a functional configuration of a motion vector detection device according to the present invention, to which an example of a motion vector detection method according to the present invention is applied.
1 includes a field delay unit 1, a camera parameter acquisition unit 2, a theoretical motion vector calculation unit 3, a vector memory 4, an initial displacement vector selection unit 5, and a motion vector calculation unit 6. It is comprised including.

  The motion vector detection apparatus 10 according to the present embodiment divides a moving image signal input for each field into a plurality of blocks having a predetermined size, for example, m pixels × n lines (m and n are integers). Thus, for each divided block, a motion for obtaining a motion vector representing the direction and magnitude of motion with the corresponding block in the moving image signal, for example, one field before delayed by the field delay unit 1 A first candidate vector group selected from the motion vectors already detected and stored in the vector memory 4, and a theoretical motion vector calculated by the theoretical motion vector calculation unit 3; That is, using the second candidate vector together, the motion vector selected by the initial displacement vector selection unit 6 is selected as the initial displacement vector of the detected block. , Starting from the initial displacement vector at less number of calculations for example, twice the gradient computing method, and a vector operation unit 7 for determining the true motion vector of 該被 detection block correctly.

  In particular, the present embodiment is characterized in how to obtain a candidate vector of an initial displacement vector, and a camera obtained by a camera parameter acquisition unit 2 from a moving image signal by using a camera vector such as panning, tilt, or zoom. A theoretical motion vector is calculated by the theoretical motion vector calculation unit 3 using the parameters, and the theoretical motion vector is used as a second candidate vector that is a candidate for the initial displacement vector. By adding to the first candidate vector group extracted from the above, the initial displacement vector selection unit 5 is configured to select a more accurate initial displacement vector.

  More specifically, the motion vector detection device 10 according to the present embodiment shown in FIG. 1 is, as described above, the camera parameter acquisition unit 2, the theoretical motion vector calculation unit 3, the vector memory 4, and the initial displacement vector selection. The unit 5 and the motion vector calculation unit 6 are included. The initial displacement vector selection unit 5 and the motion vector calculation unit 6 are respectively supplied with the current field signal and the previous field signal delayed by one field via the field delay unit 1, and the theoretical motion vector calculation unit 3 is supplied with camera parameters relating to the current field signal acquired by the camera parameter acquisition unit 2. In the initial displacement vector selection unit 5 and the motion vector calculation unit 6, the supplied field signal is divided into blocks of a predetermined size, for example, 8 pixels × 8 lines, and a motion vector for each block. Is detected.

  The vector memory 4 is a storage circuit including a RAM (Random Access Memory) that accumulates motion vectors for at least one field already detected for each block, and its input terminal serves as an output terminal of the motion vector calculation unit 6. The motion vector detected by the motion vector calculation unit 6 is sequentially updated and accumulated at an address corresponding to the position of each block divided into, for example, 8 pixels × 8 lines. Has been.

  When the camera parameter is added to the moving image signal as in the case of additional data added to the video stream when the moving image signal is in the digital format, the camera parameter acquisition unit 2 This is extracted from the image signal, and the camera parameters include shooting information at the time of shooting such as camera orientation and zoom.

  The theoretical motion vector calculation unit 3 theoretically calculates a motion vector by a camera operation in each block in the current field signal based on the camera parameter acquired from the camera parameter acquisition unit 2, and calculates the theory of the calculation result. The motion vector is output to the initial displacement vector selection unit 5 as the second candidate vector. Details of the calculation method in the theoretical motion vector calculation unit 3 for calculating the second candidate vector will be described later.

The initial displacement vector selection unit 5 selects a motion vector having a value most suitable for the motion of the detected block from the detected motion vectors obtained by the motion vector calculation of the previous field as an initial displacement vector serving as a starting point of the gradient method calculation. The selection circuit selects an appropriate motion vector from the first candidate vector group and the second candidate vector described above. Here, in the present embodiment, as the first candidate vector group, the motion vectors of the surrounding 8 blocks surrounding the block of the previous field corresponding to the detected block are set as the candidate vector group for selecting the initial displacement vector of the detected block. I will do it. Note that the first candidate vector group is not limited to this example, and may be determined from the motion feature vectors of the entire screen.
Here, the motion vector having the value most suitable for the motion of the detected block is the motion vector having the value closest to the motion vector to be finally obtained. However, since the correct motion vector is not known at the time of initial displacement vector selection, it is evaluated by using some index whether it is the closest value. There are various methods for determining this index. In the present invention, an evaluation method using the block matching method is described. In the block matching method, the difference between the pixel brightness of the detection block of the previous frame and the current frame pixel translated by the estimated motion vector is obtained for each pixel, and the sum of the difference is the smallest value. The motion vector has the most appropriate value.

  Specifically, the initial displacement vector selection unit 5 of the present embodiment is configured as shown in FIG. 2, for example. The initial displacement vector selection unit 5 shown in FIG. 2 includes a coordinate conversion unit 5a, a subtraction unit 5b, an absolute value accumulation unit 5c, and a selection unit 5d.

  In the initial displacement vector selection unit 5, the coordinate conversion unit 5a, the subtraction unit 5b, and the absolute value accumulation unit 5c are configured for each candidate vector (all candidate vectors of the first candidate vector group and the second candidate vector, ie, motion vectors). As a result, the selection unit 5d receives calculation results for all candidate vectors output from the absolute value accumulation unit 5c. In the selection unit 5d, for example, the candidate vector having the smallest output value from the absolute value accumulation unit 5c is determined as the most preferable candidate vector, and the candidate vector is selected as an initial displacement vector of the detected block. Output.

Finally, the motion vector calculation unit 6 is a calculation circuit that obtains a true motion vector by gradient method calculation using the initial displacement vector selected by the initial displacement vector selection unit 5 as a starting point. Note that the motion vector calculation method by the gradient method calculation is detailed in each of the above-mentioned patent documents and non-patent documents, and is not particularly described here, but iteratively how the initial displacement vector is used in the present invention. The gradient method will be described as an example.
Here, the motion vector calculation method in the motion vector calculation unit 6 employs an iterative gradient method that uses one or more gradient method operations, but is not limited to this. The calculation method may be used.

  For example, in the gradient method calculation, the motion displacement V1 obtained by estimating the motion amount of the current field from the coordinate position obtained by displacing the previous field signal with the initial displacement vector V0 (α, β) is expressed by the following equation (1). ) And (2).

  In equations (1) and (2), Vx is the x-direction component of the difference between the motion vectors V0 and V1, and Vy is the y-direction component of the difference between the motion vectors V0 and V1. Here, Σ represents that a sum is obtained by calculating all coordinates in a block area of m pixels × n lines, for example, 8 pixels × 8 lines. ΔX is the gradient in the x direction of the image luminance at the coordinate of interest (difference value from the adjacent pixel in the x direction), and ΔY is the gradient in the y direction of the image luminance at the coordinate of interest (the difference value from the adjacent pixel in the y direction). ) And DFD (x, y) indicate inter-field difference values between the coordinates (x, y) of the previous field and the coordinates (x + α, y + β) of the current field. Further, sign (ΔX) and sign (ΔY) are codes indicating the direction of the gradient represented by any one of +1, −1, and 0, respectively.

For example, in the case of the two-time iterative gradient method, as shown in FIG. 3, the initial displacement vector is set as V0, the first displacement amount V1 and the second displacement amount V2 are obtained, and the motion vector V obtained by adding them to the vector is obtained. Is obtained by the following equation (3).
V = V0 + V1 + V2 (3)
FIG. 3 is a vector diagram for explaining a method of calculating the motion vector V by two iteration gradient methods.

According to the expression (3), as shown in FIG. 4, the image existing in the block of coordinates (m1, n1) in the previous field is moved to the block of the coordinate position of coordinates (m1 + α0, n1 + β0) in the current field. At this time, the amount of motion is obtained as a vector V. FIG. 4 is a schematic diagram for specifically explaining the motion vector V of the image moved between the previous field one field before and the current field.
In this way, the motion vector V obtained by the motion vector calculation unit 6 shown in FIG. 1 is accumulated in the vector memory 4 and is used for calculating the motion vector for the next field and subsequent candidate vectors for selecting an initial displacement vector. Used as

  Next, the motion vector detection method for moving image signals according to the present embodiment in the above configuration will be further described together with the operation of the motion vector detection device 10 described above. In the operation state of the motion vector detection device 10, the current field signal and the previous field signal one field before input via the field delay unit 1 are sequentially transmitted to the initial displacement vector selection unit 5 and the motion vector calculation unit 6. Supplied. At the same time, a moving image signal to which camera parameters at the time of current field shooting are added is input to the camera parameter acquisition unit 2. The camera parameter acquisition unit 2 acquires current camera parameters included in the input moving image signal and outputs the acquired camera parameters to the theoretical motion vector calculation unit 3.

The theoretical motion vector calculation unit 3 theoretically calculates the motion vector of the detected block using the camera parameters input from the camera parameter acquisition unit 2. More specifically, a motion vector (theoretical motion vector) can be calculated from the camera parameters by performing the following calculation.
For example, assume that camera parameters as shown in FIG. 5 are input. Here, FIG. 5 is a schematic diagram showing an example of information regarding the camera orientation among the information included in the camera parameters added to the current field signal. This shows a case where the camera is viewed from an angle orthogonal to the shooting direction. In FIG. 5, theta is panning angle, phi represents the tilt angle, 2 [Theta] _w is the angle of view of the panning direction, 2 [phi _w indicates the angle in the tilt direction.

FIG. 6 is a schematic diagram for explaining the relationship between the screen displaying the current field signal and the direction of the camera. As shown in FIG. 6, the relationship between the camera direction and the screen will be described using the parameters in FIG. 5. The horizontal movement angle of the screen is the panning angle θ, and the vertical movement of the screen. The angle is the tilt angle φ, the field angle in the horizontal direction of the screen is the field angle 2θ _W in the panning direction, and the field angle in the vertical direction of the screen is the field angle 2φ _W in the tilt direction.
Attention is now focused on the center (x ₁ , y ₁ ) of the detected block on the screen of FIG. However, in order to simplify the explanation, it is assumed that the center of the screen has the coordinates of the origin (0, 0). Here, when the (x, y) coordinate system is replaced with the (θ, φ) axis coordinate system, the following expression (4) is obtained.

In Expression (4), (2X _W , 2Y _W ) that is twice each of X _W and Y _W indicates the screen size in the horizontal and vertical directions of the screen.
Now, panning and tilting are performed as camera operations, and if the direction of the camera is moved by (θ _V , φ _V ) during one field, the coordinates (θ, φ) of the axis coordinate system at this time (θ ₂ , φ ₂ ) moves from the coordinates (θ ₁ , φ ₁ ) as shown in the following equation (5).

When the moved coordinates (θ ₂ , φ ₂ ) are replaced with the coordinates (x ₂ , y ₂ ) of the (x, y) coordinate system, the following equation (6) is obtained.

That is, when the camera moves by (θ _V , φ _V ) during one field, the motion vector at the center of the detected block is given by (x ₂ −x ₁ , y ₂ −y ₁ ).

  Here, the calculation method for obtaining the motion vector from the camera direction of the camera parameter is not limited to the method described above, and a different method may be used. For example, you may use the affine transformation which is a kind of projective transformation described in Unexamined-Japanese-Patent No. 11-41500 "Motion vector detection apparatus and method, and recording medium" shown in the said patent document 8. FIG. However, the calculation method described above can calculate the motion vector more easily.

The theoretical motion vector calculation unit 3 obtains a coordinate change on the screen as a theoretical motion vector (x ₂ −x ₁ , y ₂ −y ₁ ) by the above-described calculation based on the camera parameters, and obtains the calculated theoretical motion vector. (X ₂ −x ₁ , y ₂ −y ₁ ) is output to the initial displacement vector selection unit 5 as a second candidate vector.

  The theoretical motion vector calculation unit 3 may calculate a theoretical motion vector for each detected block for all blocks in the screen, or the entire screen may be reduced in order to reduce the number of calculations. Dividing into a plurality of predetermined areas, calculating a theoretical motion vector only for a predetermined specific block existing in each area, and calculating the theoretical motion vector in the area where each specific block exists. You may make it use as a theoretical motion vector about each block.

  In the initial displacement vector selection unit 5, motion vectors of the eight blocks around the block corresponding to the detected block sequentially read from the vector memory 4, that is, the first candidate vector group, and the theoretical motion vector calculation unit 3 output The second candidate vector is input, and the first candidate vector group and each motion vector of the second candidate vector are supplied to the respective coordinate conversion units 5a and the previous field supplied from the field delay unit 1 The target block of the signal is displaced by the motion vector, coordinate conversion to the current field is performed, and the coordinate conversion result is supplied to each subtraction unit 5b.

  Each subtraction unit 5b performs subtraction between the previous field signal coordinate-converted by the coordinate conversion unit 5a and the input current field signal to calculate a difference for each pixel, and each difference result Is supplied to the absolute value accumulating unit 5c. Each absolute value accumulating unit 5c calculates the absolute value of the difference of each pixel, accumulates the absolute value difference for the number of pixels of the block, and selects the accumulated result as a candidate vector of each block Each is output to the unit 5d.

  Next, the selection unit 5d that has received the accumulated results for each block compares the accumulated results of the respective blocks, detects the block having the smallest accumulated result, and determines the motion vector of the block as the initial displacement vector. And supplied to the motion vector calculation unit 6.

  The motion vector calculation unit 6 calculates a true motion vector of the current field signal from the previous field signal, starting from the supplied initial displacement vector. As described above, by applying the initial displacement vector obtained from the already detected motion vector and the theoretical motion vector calculated based on the camera parameter, erroneous detection of the initial displacement vector is prevented, for example, less than twice. The true motion vector for each block of the current field signal can be correctly calculated by the number of operations by the iterative gradient method. Here, since the theoretical motion vector calculated based on the parameter parameter is added as the second candidate vector to be selected, even when there is a screen motion associated with camera operations such as panning, tilting, and zooming, It is possible to select a more correct initial displacement vector even for moving images with very little shading on the screen without being affected by changes caused by camera operation, and to calculate true motion vectors correctly. it can.

  Thus, in the motion vector detection method according to the present invention, camera parameters indicating camera operations such as panning, tilting, and zooming of the camera are acquired by the camera parameter acquisition unit 2, and at least the theoretical motion vector calculation unit 3 By calculating the motion feature vector of the entire screen based on the camera parameters and combining the obtained motion feature vector of the entire screen with the motion vector of the moving object other than the background in the screen, a more accurate initial A displacement vector can be calculated.

  In the above description, the amount of delay output after being delayed by the field delay unit 1 is one field, and a motion vector representing the magnitude and direction of motion is calculated between the previous signal and the vector. Although the case where the data is stored in the memory 4 has been described, the present invention is not limited to such a case. The present invention may be configured to obtain a motion vector between two or more fields apart from each other or a plurality of fields. good. In this case, the field delay unit 1 delays several desired plural fields and outputs respective delayed field signals. For example, when it is desired to detect a motion vector using 1 field delay and 2 field delay, the field delay unit 1 outputs a 1 field delay signal and a 2 field delay signal. These are input to the initial vector selection unit 5 and the motion vector calculation unit 6 and used for motion vector detection by a plurality of fields.

It is a functional block block diagram which shows an example of a function structure of the motion vector detection apparatus which concerns on this invention. It is a block block diagram which shows an example of the specific circuit structure of the initial displacement vector selection part of the motion vector detection apparatus which concerns on this invention. It is a vector diagram for demonstrating the calculation method of the motion vector V by the iterative gradient method twice. It is a schematic diagram for demonstrating specifically the motion vector of the image moved between the front field of 1 field before, and the present field. It is a schematic diagram which shows an example of the information regarding the direction of a camera among the information contained in the camera parameter added to the present field signal. It is a schematic diagram for demonstrating the relationship between the screen which displayed the present field signal, and the direction of a camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Field delay part, 2 ... Camera parameter acquisition part, 3 ... Theoretical motion vector calculation part, 4 ... Vector memory, 5 ... Initial displacement vector selection part, 6 ... Motion vector calculation part, 10 ... Motion vector detection apparatus.

Claims (6)

  A motion image signal field is divided into a plurality of predetermined blocks of a predetermined size, and a motion representing the magnitude and direction of motion between the motion image signals separated by at least one field for each of the divided blocks. In a motion vector detection method of a moving image signal for detecting a vector, a camera parameter acquisition step for acquiring the camera parameter from a moving image signal to which camera parameters including information on a camera direction and zoom at the time of shooting are added; A theoretical motion vector calculating step for calculating a coordinate change on the screen as a theoretical motion vector based on the camera parameter acquired by the camera parameter acquiring step, and storing a motion vector detected for each block for at least one field. Storage step and the storage step The motion vectors of a plurality of blocks located in the vicinity of the detected block among the detected motion vectors are read out as a first candidate vector group for selecting an initial displacement vector of the detected block, and the first candidate vector group An initial stage of selecting a motion vector having a value most suitable for the motion of the detected block as an initial displacement vector of the detected block from the second candidate vectors that are the theoretical motion vectors calculated by the theoretical motion vector calculating step. A displacement vector selecting step, and performing one or more operations starting from the initial displacement vector selected in the initial displacement vector selecting step to obtain and output a motion vector of the detected block, and the obtained motion vector The storage step is used to calculate the motion vector of the moving image signal after the next field. Motion vector detecting method, characterized in that a, a motion vector calculation step of storing the flop.   The motion vector detection method according to claim 1, wherein the theoretical motion vector calculation step calculates the theoretical motion vector for every detected block for all the blocks in the screen, Dividing into a plurality of predetermined areas, calculating the theoretical motion vector only for a predetermined specific block existing in each area, and calculating the theoretical motion vector in the area where each specific block exists. A motion vector detection method characterized in that it is used as a theoretical motion vector for each block.   A motion image signal field is divided into a plurality of predetermined blocks of a predetermined size, and a motion representing the magnitude and direction of motion between the motion image signals separated by at least one field for each of the divided blocks. In a motion vector detection device for a moving image signal for detecting a vector, camera parameter acquisition means for acquiring the camera parameter from a moving image signal to which camera parameters including information on the camera orientation and zoom at the time of shooting are added , Theoretical motion vector computing means for computing coordinate changes on the screen as theoretical motion vectors based on the camera parameters obtained by the camera parameter obtaining means, and storing at least one field of motion vectors detected for each block Storage means for storing the motion vector stored in the storage means. The motion vectors of a plurality of blocks located in the vicinity of the detected block are read out as a first candidate vector group for selecting an initial displacement vector of the detected block, and the first candidate vector group and the theoretical motion vector calculation are read out. Initial displacement vector selection means for selecting a motion vector having a value most suitable for the motion of the detected block from among the second candidate vectors that are the theoretical motion vectors calculated by the means, as an initial displacement vector of the detected block; The initial displacement vector selected by the initial displacement vector selection means is used as a starting point to perform one or more operations to obtain and output the motion vector of the detected block, and the obtained motion vector is A motion vector calculation unit stored by the storage means for calculating a motion vector of a moving image signal When motion vector detection apparatus, characterized in that a.   4. The motion vector detection device according to claim 3, wherein the theoretical motion vector calculation means calculates the theoretical motion vector for every detected block for all blocks in the screen, or the entire screen is preliminarily processed. Dividing into a plurality of predetermined areas, calculating the theoretical motion vector only for a predetermined specific block existing in each area, and calculating the theoretical motion vector in the area where each specific block exists. A motion vector detection apparatus characterized by being used as a theoretical motion vector for each block.   A motion vector detection program characterized by realizing the motion vector detection method according to claim 1 or 2 as a program executable by a computer.   6. A program recording medium, wherein the motion vector detection program according to claim 5 is recorded on a computer-readable recording medium.

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