JP3527299B2 - Motion vector detection method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a motion vector of an image, and more particularly to an image processing for applying image motion compensation to a television image signal of 2: 1 interlaced scanning. The present invention relates to a motion vector detection method and apparatus.

[0002]

2. Description of the Related Art As a principle method of detecting a motion vector, a block matching method, a gradient method, a phase correlation method and the like have been proposed so far, all of which are well-known methods. In addition, Japanese Patent Application Laid-Open No. Hei 6 (1994) -207, filed by the present applicant as a method of improving image quality by removing image quality interference (interlace interference) in a current 2: 1 interlaced scanning television image signal.
-133280 (conventional example 1) and JP-A-6-121
No. 288 (Conventional Example 2) has an invention described in a published patent publication. The invention 1 of the prior art "scan conversion apparatus for image signals" is a motion-compensated progressive scan conversion for converting an interlaced scanning television image signal into progressive scan. The invention "the motion vector detection method" of the prior art 2 is The present invention relates to a method for detecting a motion vector used for such scan conversion.

[0003]

[Problems that the Invention is to Solve In the motion compensated progressive scan conversion in the conventional example 1, only when the vertical component V _y is the number in the field per frame scanning line motion of the motion vector of the even can effective image quality improvement Therefore, the invention of Conventional Example 2 was made. In conventional example 2 invention limits the V _y to even an oblique edge and the longitudinal edges. However, as will be described later, only the diagonal edge has a positive meaning of limiting to an even number, and the vertical edge may be limited to an even number.

On the other hand, the interpolation selection judgment circuit which is a component of the conventional example 1 cannot be said to be perfect at present, and a judgment error occurs depending on an image, and the image quality is deteriorated. This error is smaller as the reliability of the detected motion vector is higher. Limiting V _y to an even number in motion vector detection leads to a reduction in reliability because not all possibilities have been verified. For this reason, in the detection method of Conventional Example 2, although image quality is improved at oblique edges, conversion artifacts (image quality disturbance peculiar to the conversion apparatus due to a determination error or the like) are slightly increased in other images. I was

Accordingly, the object of the present invention is to provide a second conventional example.
It is an object of the present invention to provide a motion vector detecting method which can improve the problem of the method for detecting the motion vector and provide a progressive scan conversion output with higher image quality.

[0006]

In order to achieve the above object, a motion vector detecting method according to the present invention is applied to an image processing for applying image motion compensation to a television image signal of 2: 1 interlaced scanning. In detecting a motion vector of an image from an interlaced scanning signal, a first motion vector detecting circuit for detecting a motion vector V ₁ from a 2: 1 interlaced scanning signal without limiting a motion vector candidate; Is limited to an even number in the unit of the number of scanning lines in a frame / field, and
1 interlace and a second motion vector detection circuit for detecting a motion vector V ₂ from the scanning signal, the first motion vector detection circuit and vector V ₁ respectively detected by the second motion vector detection circuit and V ₂ and a selection switch for selecting a vector which requires from in the selection switch, when the motion vector is no difference in the amount of the left and right diagonal components in the image portion to be detected selects vector V _1, left and right diagonal component If there is a difference in the amount of is characterized in that it has to select the vector V _2.

Further, the motion vector detecting method according to the present invention
For detecting image motion vectors from the interlaced scanning signal for image processing that applies image motion compensation to a 2: 1 interlaced scanning television image signal, there is no limitation on the motion vector candidates without any limitation. : 1 interlaced first motion vector detection circuit for detecting a motion vector V ₁ from the scanning signal, the limit to even the unit of the vertical component of the frame number of scanning lines / field motion vector 2: 1 interlace a second motion vector detection circuit for detecting a motion vector V ₂ from the race scanning signal,
A selection switch for selecting a required vector from the vectors V ₁ and V ₂ detected by the first motion vector detection circuit and the second motion vector detection circuit, respectively. There is no difference in the amount of the left and right diagonal components in the detected image portion, and the detection error E ₁ with respect to the motion vector V ₁ output from the first motion vector detection circuit and the detection error E ₁ output from the second motion vector detection circuit that motion only if there is a difference between the detection error E ₂ for the vector V ₂ selects the motion vector V ₁ output from the first motion vector detection circuit, the second motion vector detection in other cases it is characterized in that selecting a motion vector V ₂ output from the circuit.

In the motion vector detecting method according to the present invention, the first motion vector detecting circuit is constituted by a circuit for detecting a motion vector giving a minimum inter-field difference, and the second motion vector detecting / detecting circuit is controlled by a minimum. And a circuit for detecting a motion vector that gives a difference between frames.

Further, the motion vector detecting device according to the present invention comprises: a first motion vector detecting circuit for detecting a motion vector V ₁ from a 2: 1 interlaced scanning signal without any restriction on a motion vector candidate; the vertical component is limited to an even number in units of frames in the number of scanning lines / field, the 2: 1 and the second motion vector detection circuit for detecting a motion vector V ₂ from interlaced scan signal, the first motion A selection switch for selecting and taking out _{one of} the vectors V ₁ and V ₂ detected by the vector detection circuit and the second motion vector detection circuit as a motion vector of the 2: 1 interlaced scanning signal,
If it is determined that there is no difference between the left and right diagonal components in the image in the pixel block where the motion vector of the 2: 1 interlaced scanning signal is detected, the output V ₁ of the first motion vector detection circuit is used. When it is determined that there is a difference between the amounts of the left and right diagonal components, a control signal for controlling the selection switch is output so as to select and take out the output V2 of the _second motion vector detection circuit. An image direction detection circuit is provided.

Further, the present invention a motion vector detecting device, a motion 2 without providing a candidate restriction vectors: first detecting a detection error E ₁ of 1 interlaced motion from the scanning signal vector V ₁ and the motion vector V ₁ And the vertical component of the motion vector is limited to an even number in the unit of the number of scanning lines in a frame / field.
A second motion vector detection circuit for detecting the detection error E ₂ of the motion vector V ₂ and the motion vector V ₂ from 1 interlaced signal, the first motion vector detection circuit and the second motion vector detection circuit And a selection switch for selecting and extracting _{one of} the vectors V ₁ and V ₂ detected as the motion vector of the 2: 1 interlaced scanning signal, and the motion vector of the 2: 1 interlaced scanning signal. Image directionality that produces different logic outputs when it is determined that there is no difference in the amount of left and right diagonal components in the image in the detected pixel block, and when it is determined that there is a difference in the amount of left and right diagonal components a detection circuit, connected to said first and second motion vector detection circuit receives the detection error E ₂ for the detected error E ₁ and the motion vector V ₂ for the motion vector V ₁ And these detection errors E ₁ and E
And error comparison circuit that generates a different logical output and when there is no difference and if there is a difference ₂ receives the logic output from the logic output and error comparison circuit from the image direction detection circuit, based on these logic output And an AND gate for controlling the selection switch. The AND gate is provided with a logic corresponding to a case where it is determined by the image direction detection circuit that there is no difference in the amount of left and right oblique components in the image in the pixel block. The motion vector V ₁ output from the first motion vector detection circuit is selected only when an output is received and a logical output indicating that there is a difference between the detection errors E ₁ and E ₂ is received from the error comparison circuit. even in other cases and controls the selection switch to select the motion vector V ₂ output from the second motion vector detection circuit It is.

Further, in the motion vector detecting apparatus according to the present invention, the first motion vector detecting circuit is constituted by a circuit for detecting a motion vector which gives a minimum inter-field difference, and the second motion vector detecting circuit is a minimum motion vector detecting circuit. It is characterized by comprising a circuit for detecting a motion vector that gives an inter-frame difference.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows the configuration of an embodiment of the motion vector detecting device according to the present invention. Prior to this, the technical background of the present invention will be described in some detail once again with reference to FIGS.

FIG. 2 shows a prior art 1 (Japanese Patent Laid-Open No. 6-1).
No. 33280).
FIG. 2 shows a configuration block diagram. The image input signal p of this device has, for example, 525 scanning lines, a field frequency of 60 Hz,
This is a signal of 2: 1 interlace scanning, and the output signal at this time is a sequential scanning signal of 525 lines / 60 Hz / 1: 1.

In this apparatus, a signal q of an interpolation scanning line necessary for progressive scanning conversion is converted into an output signal qm of a motion compensation interpolation circuit 13.
and c, is obtained by mixing in accordance with the mixing ratio K _m in the mixer 15 the output signal qvf in intra-field interpolation circuit 14. p and q are time-axis converted by the time-axis conversion circuit 16 and then combined to form an output signal. The motion vector detector 11 detects a motion vector _Vc of the image from the input signal p for each block of the image. In circuit 13, V _C
Performs motion compensated interpolation of scan lines is used to determine the determined K _m whether interpolation selection judging circuit 12, V _c is precisely for each pixel. Thus the motion vector V _c affect the operation of each section, the contents of which greatly affects the conversion quality.

FIG. 3 is a diagram of the input image p as viewed on the time-vertical axis, and white circles indicate positions where scanning lines exist.
Focusing on the scanning line a now, it is necessary to create an interpolation scanning line q in the middle of the immediately above scanning line b. Motion vector V
_c vertical component of 2n (frame number of scanning lines / field, n represents an integer) can be interpolated if it shifts and a scan line c or d of the previous field as shown in Figure in accordance with the value of V _y in the case of However, otherwise, it is not possible to perform effective interpolation in terms of image quality (1 to be interpolated in FIG. 3).
No signal before field. For a more detailed description of FIGS. 2 and 3, see the publication of Conventional Example 1). Motion vector detection is generally performed for each small block of an image.
When the images are viewed locally, they can be roughly classified as shown in FIG.
(A), (b), and (c) of FIG. 4 are edge images, and (d) of FIG. 4 is an example of other images. The image other than the edge includes a lattice image as shown in FIG. 4D, a random image such as noise, a point image, and the like. Table 1 shows whether or not interlace interference can be removed by motion compensated progressive scan conversion. When the motion of the image is V _y = 2n, it can be removed (○) in any case, but when V _y ≠ 2n, it cannot be removed in some cases (×).

When the motion of the image is other than V _y = 2n, the oblique edge image cannot be removed if the vertical component V _yc of the vector V _c used for motion compensation is V _yc = V _y , but V _yc的_に is intentionally used. and _{V y, V yc = 2n o} (n o is an integer other than n)
Then, the image can be removed (the reason is the local simplicity of the edge image, and for details, see the above-mentioned prior art 2).
Vertical edges can always be removed, and horizontal edge images and other images (except for uniform images with little change) cannot always be removed.

[0017]

[Table 1]

[0018] From the above, the outside lateral edge conventional example 2 of the motion vector detecting method was always a way such that V _yc = 2n _o. However, the operation of the interpolation selection determination circuit 12 is not perfect at present, and a determination error may occur depending on the image. For this reason, artifacts (image quality disturbance peculiar to the conversion device) occur in the interpolation of the scanning lines, and the converted image quality is deteriorated. This judgment error is caused by the motion vector V _c
The higher the reliability, the less. Restricting V _c to V _yc = 2n _o leads to a decrease in reliability because an optimal one is not detected from among all motion vector candidates in motion vector detection. Therefore, in the motion vector detection method of the present invention, V
without a limit of _yc = 2n _o, it is intended to detect more reliable motion vector.

Next, an embodiment according to the method of the present invention will be described. The entire circuit shown in FIG. 1 can be used as the motion vector detecting unit 11 shown in FIG. The motion vector detection circuit 1 detects an optimum vector for each pixel block without any restriction from the input signal p. This is a state called full search in the block matching method, which is one of the motion vector detection methods, for example. At this time, the detection accuracy of the vector may be an integer in both horizontal and vertical directions, or may be finer than that. The output of the circuit 1 is defined as a vector V ₁ (horizontal component V _x1 , vertical component V _y1 ).

Meanwhile, the motion vector detection circuit 2 is the vertical component V _y2 of the vector detecting V _y2 = 2n _o (n _o is an integer) detects the optimal vector V ₂ for each block under the condition that it is I do. It is possible to impose such a condition in motion vector detection even in an actual circuit. For example, in the block matching method to search for the minimum motion vector matching errors, but may be limited to the search candidate vector of V _y2 = 2n _o. The vectors V ₁ and V ₂ are selected by the switch 3 according to a signal K _ob described later, and become output vectors V _c (V _xc , V _yc ).

The oblique right component extracting circuit 4 detects the amount S _{ob1 of the} oblique right component of the image in the pixel block. For example, FIG.
(B) is a right oblique edge image, in which _Sob1 has a large value. Conversely, the left oblique component extraction circuit 5 detects the amount S _ob2 of the left oblique component in the block. The direction determining circuit 6 compares S _ob1 and S _ob2, and determines that there is no direction and _{sets the} control signal K _ob to “1” if there is no significant difference between the two values. If there is a significant difference, _{Kob is set} to "0". By controlling the switch 3 with this K _ob , the vector V ₁ is selected when K _ob is “1”, that is, when the image does not have a remarkably oblique direction on either the left or right, and the vector V ₂ is selected if there is any. . These circuits 4, 5, and 6 constitute an image direction detection circuit 7 as a whole.

Hereinafter, more specific examples of the circuits 4, 5, and 6 will be described. FIG. 5 is a specific example of the circuits 4 and 5. The image input signal p is 1H delay (one line delay) H21, H
22. The input signals p and H21,
The output of H22 is connected to the horizontal delays 23-27 of the image in clock units. Here, for example, delay 2
The (LS) D of 4 represents the (LS) clock delay. The same applies to other cases. L is a fixed value, and S is a circuit parameter. The value of S is determined by cut and try in an actual circuit. These delays 23,
And output signals of delays 24-27 are respectively applied to signals a and e.
6 to FIG. 6, the arrangement on these screens is as shown in FIG.
However, this figure is for S = 2. The adder 28 adds the signals e and h, and the output thereof is divided by a 1/2 coefficient unit 29 into 1 /
Multiply by two. The subtractor 30 subtracts the output of the coefficient unit 29 from the signal a to obtain a signal obd1. That is, obd1 = a− (e + h) / 2 (1), and as shown in FIG. 6, the signal obd1 is the output of the high-pass filter in the diagonally left direction. Therefore, the signal obd1 has a value whose absolute value is large when the image is an oblique right edge or the like.

Adder 31, 1/2 coefficient unit 32, subtractor 3
3 similarly forms a high-pass filter in the oblique right direction, and the output obd2 = a− (g + f) / 2 (2) has a large absolute value in a left oblique edge image or the like. These signals obd1 and obd2 are calculated for each pixel. These are further converted to the square values of the values by the squarers 34 and 35, and integrated in the pixel blocks (B) by the integrators 36 and 37. The output signals of the integrators 36 and 37 are the amount S _{ob1 of the} oblique right component and the amount S _{ob2 of} the oblique left component in the _block.
It is.

FIG. 7 shows a specific example of the direction determining circuit 6.
The divider 41 _obtains (S _ob1 / S _ob2 ), and the divider 42 _{obtains the} reciprocal (S _ob2 / S _ob1 ). In the maximum value detection circuit (MAX) 43, the larger one of the two is selected. The output of the circuit 43 takes a value of 1 or more close to 1 when S _ob1 and S _ob2 take _{substantially the} same value, but takes a value sufficiently larger than 1 if there is a large difference between the two values. For example, in each image shown in FIGS. 4A, 4C, and 4D, S
_Ob1 and _Sob2 both take large values, and the output of the circuit 43 is close to 1. However, in the right oblique edge image of FIG. 3B, _Sob1 is large and _Sob2 is small, and the output of the circuit 43 is small. Has a large value. In this way, it is possible to determine whether the image is an oblique edge image based on the magnitude of the output of the circuit 43. The output of the comparator 44 in the circuit 43 is compared with the threshold value TH _ob, the K _ob output if smaller than the value TH _ob "1",
Otherwise, it is set to “0”. TH _ob is determined by cut-and-try in an actual circuit.

FIG. 8 shows an embodiment according to claim 2 of the present invention. The circuits 1, 2, 3, 7 are the same as in FIG. However, the error E _1, E ₂ are outputted simultaneously for the vector V _1, V ₂ each detected from the circuits 1 and 2. This error is one measure of the reliability of the vector, and a normal motion vector detection algorithm requires a numerical value similar to some error when detecting a vector. For example, it is a matching error in the block matching method. The ratio of the errors E ₂ and E ₁ (E ₂ / E
₁ ) is obtained, and the ratio is compared with the threshold value Ther in the comparator 52, and the output Ker of the comparator 52 is set to "1" only when the ratio is larger than THer. Otherwise K
er becomes “0”. That Ker only when E ₂ is sufficiently large as compared with E ₁ is "1". These 51,5
2 constitutes an error comparison circuit as a whole. The threshold value Ther is determined by cut and try. Ke
AND of the output of the circuit 7 and _Kob is the AND gate 5
4, the output of gate 54 controls switch 3.

The meaning of these circuits is as follows.
The characteristics of the vectors V ₁ and V ₂ are summarized as follows. (Interlace interference removal capacity) V _1: V ₂ less than V _2: large (especially diagonal edge image) (reliability vector) V _1: High V _2: less than V ₁ equal to or V ₁

[0027] Therefore, the circuit of Figure 1 is to the outside of a large diagonal edge image in comparison with the particular vector V ₁ interference removal ability of V ₂ tries to select a reliable vector V _1. However, the determination of whether the diagonal edge image always full and it can not be said that in the real complex image, there is a possibility that the selected vector V ₁ in the image should be selected vector V _2. On the other hand, regarding reliability, the vector V ₁
Is always more reliable or equal to V _2, but the vector V ₁
And reliability of V ₂ (the value of the error) in many cases not so different. In such a case, the vector V ₂ should be expected to have better interference rejection capability than to select the vector V ₁ . Therefore the circuit in FIG. 8 is intended to select vector V ₁ only when there is a difference in reliability of no directionality, and the vector V ₁ and V ₂ to the image.

Next, an embodiment according to claim 3 of the present invention will be described. The block matching method used in the motion vector detection method is currently the most widely used motion vector detection method because of its performance, simplicity of the algorithm, and the like. When detecting a motion vector from a 2: 1 interlaced scanning signal by the block matching method, two methods are conceivable. That is, there are a method of configuring a circuit to provide the minimum inter-frame difference as a vector, and a method of configuring a circuit to provide the minimum inter-field difference as a vector. However, each of these has other disadvantages.

The former is the vertical component V _{y of the} motion vector.
Can be easily detected in both the even and odd cases. However, since a vector is detected based on the difference between images two fields apart from each other in time, detection errors are likely to occur particularly in an image having a periodic structure such as a striped pattern. When applied, visually noticeable image quality disturbances occur.

In the latter case, since the vector is detected based on the difference between one field which is the minimum unit in time, there is no problem of such an error. However, as described in the above-mentioned conventional example 1, _Vy is an even-numbered vector while Vy is effective in terms of image quality in inter-field motion compensation.
The latter can not this V _y is easily detected even vector. If the image signal is spatially interpolated before the inter-field difference is obtained, it is possible to detect even-numbered vectors. However, the interpolated signal includes aliasing related to many spatial frequency spectra, and accurate even motion vector detection cannot be expected even though the circuit scale required for interpolation is large.

[0031] Anyway, in claim 3, in V _y is a frame in number of scanning lines / field unit, the aforementioned detection circuit that needs to detect the motion vector is limited to even number 2
Is composed of a block matching circuit that detects a vector that gives a minimum inter-frame difference, and it is not necessary to detect an even-numbered motion.
Aims to further reduce errors in vector detection according to the second aspect of the present invention and to accurately detect a motion vector by configuring a circuit by block matching for detecting a vector that gives a minimum inter-field difference. . Claim 2 does not take such considerations into account.

FIG. 9 shows a motion vector detecting circuit according to a third embodiment of the present invention. Blocks (circuits) having the same operation as the block explained in FIG. Numbered. The signal p input to the circuit is, for example, a television image signal of 525 scanning lines, a field frequency of 60 Hz, and 2: 1 interlaced scanning.

The broken line block 1 in FIG.
6 for each suitable block of the image (for example, horizontal 16 pixels ×
The motion vector detecting circuit 1 detects a motion vector every eight vertical lines. The circuit 1 is configured based on a block matching method. In the block matching method, when an object is moving in parallel at a speed of V _T (pixels / frame) during one frame period, if the image of one frame before is shifted by V _T pixels, the image matches the image of the current frame. , Utilizing the principle that the intra-block accumulated value of the inter-frame difference indicates the minimum value.

In the figure, the signal p is delayed in the delay 61 by (one field + V _T1 ). V
_T1 ( _{VxT1 , VyT1} ) is a candidate vector to be subjected to motion vector detection, and the candidate vector generation circuit 62 sequentially generates all candidate vectors within a range set in advance according to specifications. Here, V _{xT1 and} V _yT1 are a horizontal component and a vertical component of V _T1 , respectively. Element 6
The operations of 1,62 will be described in more detail later. In the subtractor 63, the difference between the signal p and the output of the delay 61 is calculated, whereby the motion compensation inter-field difference signal dfd1 (displace
d field difference) is required. The block area setting circuit 64 generates a block area signal B indicating whether the pixel is a pixel in a preset block. Element 65, the absolute value of the block in the accumulated value of dfdl, Σ _B | dfd1 | a seek. This value is the candidate vector V _T1
And this is represented by DFDl (V _T1 ). DFD
1 (V _T1 ) is the matching error of V _T1 for that block. The minimum value detection circuit 66 obtains the minimum value of DFD1, and outputs V _T1 that generates the minimum value as the motion vector V ₁ (V _x1, V _y1 ) of the block. Also, DF
The minimum value of D1 is output as an error E ₁ vector V _1.

The broken line block 2 is composed of components 71 to 76, and limits the vertical component of the motion vector to only an even number in the unit of (scanning line / field).
This is a motion vector detection circuit that detects a motion vector for each block same as the circuit 1. Like the circuit 1, the circuit 2 is also configured based on the block matching method.

In the figure, the signal p is delayed by (1 frame + 2V _T2 ) in the delay 71. V
_T2 (V _xT2 , V _yT2 ) is a candidate vector for which a motion vector is to be detected, and a preset candidate vector is sequentially generated from the candidate vector generation circuit 72. Here, V _XT2, V _Yt2 the horizontal direction component of each V _T2, a vertical component. The operation of elements 71 and 72 will be described in more detail later. By subtracting the difference between the signal p and the output of the delay 71 in the subtractor 73, a motion compensated inter-frame difference signal dfd2 (displaced frame difference) is obtained. The operation of elements 74-76 is exactly the same as circuits 64-66. Element 76 includes a motion vector V ₂ (V _x2,
V _y2 ) and its error E ₂ . Circuits 7, 5
According to 3, 54 and 3, a more accurate vector suitable for the inter-field motion compensation of the image p is selected from V ₁ and V ₂ and output as an output vector V _c (V _xc, V _yc ). These circuits are the same as those shown in FIG.

Next, the elements 61, 62, 7 will be described with reference to FIG.
The operations of 1, 72 will be described. The figure shows the scanning of the image viewed in a time-vertical plane. The horizontal axis of the figure is time t,
The vertical axis represents the vertical direction y of the screen. A, B, C,
---, a, b, c, ---, etc. are symbols attached to each scanning line. Hereinafter, consider the vertical component V _y of candidate vectors (hereinafter T1, T2 suffixes omitted except where specifically required for simplification of description). here,
The unit of V _y is (in frame) scan lines / field. Regarding the horizontal component, there are no special circumstances regarding evenness as follows.

Firstly, with regard to the inter-frame difference, relationship between the position values and the scanning lines of the V _y is as shown in FIG. 10 (a).
In the circuit 2 based on the difference between frames, the delay 71
Is 525H (H is one line (scanning line within one field)), and when the signal p scans the scanning line R, the output of the delay 71 is just one frame before, that is, the scanning line E. . Therefore, the difference between E and R is V
_This is an inter-frame difference corresponding to _y = 0. When the delay amount is reduced by one line to 524H, the output of the delay 71 is the scanning line F, and (FR) is the inter-frame difference corresponding to V _y = 1. Since one line is equivalent to two scanning lines in a frame, the delay amount of the delay 71 can be expressed as (1 frame + 2V _T2 ) as described above. Less than,
Similarly, the difference between frames as shown in FIG. 10A corresponds to V _y = ---, -4, -3, ---, 3, 4,.
If the minimum value of these differences is detected, motion vectors of all integer values for V _y can be detected. However, since circuit 2 limits V _yT2 to only even numbers, element 72
_yT2 is sequentially outputs only the V _T2 is an even number.

As for the difference between the fields, the relationship between V _y and the scanning line is as shown in FIG. In the circuit 1 based on the difference between fields, when the delay amount of the delay 61 is 262H and the signal p scans the scanning line R, the output of the delay 61 is the scanning line e. At this time, (e−R) is an inter-field difference corresponding to V _y = 1. When the delay amount is reduced by one line to 261H, the output of the delay 61 is the scanning line f, and (f−
R) is the inter-field difference corresponding to V _y = 3. Therefore, the delay amount of the delay 61 can be expressed as (1 field + V _T1 ), similarly to the delay 71. Hereinafter, similarly,
The inter-field difference as shown in FIG. 10B corresponds to V _y = ---, -5, -3, ---, 3, 5,. When a motion vector is detected by detecting the minimum value of these differences, only odd-numbered vectors can be detected for V _y without imposing any circuit limitation on motion vector candidates. The element 62 sequentially outputs all candidate vectors that can be detected by such an inter-field difference.

As described above, the circuit 1 can detect only an odd vector of V _y, but the operation is necessary and sufficient for the embodiment of FIG. In the circuit of FIG. 8 and the invention of claim 2, when the obliqueness of the image is not remarkable, the errors E ₁ and E
Selection of V _1, V ₂ is made by _two large and small. Therefore, even not be detected only V _y is odd motion as V _1, if the diagonal direction is not significant, the vertical component of the true motion of an image is a good match with regard V ₁ if an even number Since E ₁ > E ₂ and V ₂ is selected, a correct vector can be detected as the whole circuit of FIG.

As described above, in addition to the correct operation of the circuit shown in FIG. 9, the circuit 1 is a detection circuit based on the difference between fields, so that the detection error of the motion vector causing image quality disturbance is obtained as follows. Can be reduced.

FIG. 11 shows an example of motion vector detection and motion compensation for a certain image. The image is two horizontal line images in which the black and white are inverted every two scanning lines in the field, and the vertical component of the true movement is V _y = 1. The notation in the figure is the same as that in FIG. 10 except that black and white are added to the scanning lines.

[0043] In FIG. 11, if the detected vector by the interframe difference, corresponding to the motion of the _{V y = 1 (J-R} ), (K-R 1), corresponding to the motion of the V _y = 5 (L −R), (M−R ¹ ) and the like are all zero, so that any of V _y = 1 and 5 is a strong candidate for the vector. Which one is selected is determined by a reason not related to the original image content, such as noise included in the image or a preset priority of a circuit. But,
When these vectors are used for inter-field motion compensation as described in Conventional Example 1, a large difference occurs in the result of motion compensation. In other words, when interpolating the scanning line by the motion compensation in the middle of the R _m points of R and R ^1, scanning lines if V _y = 1 is detected j, white scan line as the average value of k is correctly interpolated . However, when V _y = 5 is detected, l, m
The black scan line is interpolated as the average of. This is apparently a false signal, and often causes a noticeable image disturbance even in an actual image. As described above, in the motion vector detection based on the inter-frame difference, a motion vector candidate that causes image quality disturbance cannot be excluded.

On the other hand, when a vector is detected based on an inter-field difference, since the difference (1-R) and (m-R ¹ ) have large values, a motion vector of V _y = 5 must be detected. There is no. Since the differences (s−R) and (t−R ¹ ) are also zero, the motion of V _y = 9 may be detected,
In this case, a white scanning line is correctly interpolated as an average value of s and t, and there is no problem with respect to inter-field motion compensation. Thus, the circuit of FIG. 9 can always detect a correct motion vector for motion compensation for a motion having an odd V _y .

Although the present invention has been described in detail with reference to the examples, the present invention is not limited to these examples.
It is obvious that various modifications and changes are possible within the gist of the invention. For example, in the embodiment of the present invention, a block matching method is assumed as a basic motion vector detection method. However, the present invention can be realized by using another detection method (for example, a gradient method).

[0046]

As described above, according to the present invention, the motion vectors used for the image processing for applying the motion compensation of the image to the interlaced-scanned television image signal are appropriately obtained in accordance with the type of the image. And a progressive scan conversion output with higher image quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a motion vector detection device according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a motion-compensated progressive scan conversion device.

FIG. 3 is a diagram for explaining the operation of the apparatus shown in FIG. 2;

FIG. 4 is a diagram showing types of images.

FIG. 5 is a diagram showing a specific circuit example of circuits 4 and 5 of the apparatus shown in FIG. 1;

FIG. 6 is a diagram for explaining the operation of the circuit shown in FIG. 5;

7 is a diagram showing a specific circuit example of the circuit 6 of the apparatus shown in FIG. 1;

FIG. 8 is a diagram showing a configuration of an embodiment according to claim 2 of the present invention.

FIG. 9 is a diagram showing a configuration of an embodiment according to claim 3 of the present invention.

FIG. 10 is a diagram illustrating an inter-frame difference and an inter-field difference.

FIG. 11 is a diagram illustrating an operation example of motion vector detection and motion compensation.

[Explanation of symbols]

1 Motion vector detection circuit 1 2 Motion vector detection circuit 2 3 Selection switch 4 Right diagonal component extraction circuit 5 Left diagonal component extraction circuit 6 Directivity judgment circuit 7. Image direction detection circuit 11 Motion vector detector 12 Interpolation selection judgment circuit 13 Motion compensation interpolation circuit 14 In-field interpolation circuit 15 mixer 16 Time axis conversion circuit 21,22 1 line delay 23-27 Horizontal Delay 28, 31 adder 29, 32 1/2 multiplier 30, 33, 63, 73 Subtractor 34,35 squarer 36, 37 Integrator 41, 42, 51 divider 43 Maximum value detection circuit 44, 52 comparator 53 Error comparison circuit 54 AND gate 61, 71 delay circuit 62,72 Candidate vector generation circuit 64, 74 block area setting circuit 65, 75 In-block accumulation circuit of absolute value 66, 76 Minimum value detection circuit

Claims (6)

(57) [Claims] 1. An image processing for applying image motion compensation to a 2: 1 interlaced scanning television image signal. In detecting an image motion vector from the interlaced scanning signal, the motion vector is limited to motion vector candidates. 2 is not provided: 1: a first motion vector detection circuit for detecting a motion vector V ₁ from interlaced scan signal, by limiting the even in the unit of the vertical component of the frame number of scanning lines / field motion vector the 2: 1 interlaced from the scanning signal a second to detect the motion vector V ₂ motion vector detection circuit and said first motion vector detection circuit and the second motion vectors respectively detected by the detection circuit vector V ₁ and a selection switch for selecting a vector which requires the V ₂ and, in the selection switch, a motion vector is detected Motion vector select vector V ₁ was when there is no difference in the amount of the left and right oblique components to the image portion, when there is a difference in the amount of the left and right oblique components, characterized in that to choose a vector V ₂ Detection method. 2. An image processing for applying image motion compensation to a 2: 1 interlaced scanning television image signal. In detecting an image motion vector from the interlaced scanning signal, the motion vector is limited to motion vector candidates. 2 is not provided: 1: a first motion vector detection circuit for detecting a motion vector V ₁ from interlaced scan signal, by limiting the even in the unit of the vertical component of the frame number of scanning lines / field motion vector the 2: 1 interlaced from the scanning signal a second to detect the motion vector V ₂ motion vector detection circuit and said first motion vector detection circuit and the second motion vectors respectively detected by the detection circuit vector V ₁ and a selection switch for selecting a vector which requires the V ₂ and, in the selection switch, a motion vector is detected
There is no difference in the amount of the left and right oblique components in the image portion, and
1 motion vector output from the motion vector detection circuit
The second motion vector detection and detection error E ₁ for the V ₁
Detection error for the motion vector V ₂ output from the output circuit
Wherein only when there is a difference in the difference E ₂ a first motion vector detection
Select the motion vector V ₁ output from the output circuit ,
Otherwise, the second motion vector detection circuit outputs
The motion vector detection method and selects the motion vector V ₂ to be force. 3. The method according to claim 2, wherein said first motion vector detection circuit comprises a circuit for detecting a motion vector giving a minimum inter-field difference, and said second motion vector detection and detection circuit comprises a minimum motion vector detection and detection circuit. A motion vector detecting circuit that detects a motion vector that gives a difference between frames. 4. A method without limiting the motion vector candidates,
A first motion vector detection circuit for detecting a motion vector V ₁ from 1 interlaced signal, by limiting the even in the unit of the vertical component of the frame number of scanning lines / field motion vector, the 2: 1 interlace a second motion vector detection circuit for detecting a motion vector V ₂ from the race scanning signal, the first motion vector detection circuit and the second motion vector detection vector V ₁ respectively detected by the circuit and V ₂
Among the either 2: 1 selection switch retrieving selected as a motion vector of an interlaced scan signal, the 2: 1 image left or right oblique interlaced signal pixel block motion vector is detected in the If it is determined that there is no difference in the amount of the component, the output V ₁ of the first motion vector detection circuit is used. motion vector detecting apparatus characterized by comprising an image direction detection circuit for outputting a control signal for controlling the selection switch to the output V ₂ of the detection circuit is taken out by selecting respectively. 5. The method without limiting the motion vector candidates:
1 a first motion vector detection circuit for detecting the detection error E ₁ of the motion vector V ₁ and the motion vector V ₁ from interlaced scan signal, in units of frames in the number of scanning lines / field vertical component of the motion vector is limited to an even number, the 2: 1 interlaced from the scanning signal and the second motion vector detection circuit for detecting the detection error E ₂ of the motion vector V ₂ and the motion vector V _2, the first motion vector detection circuit And the vectors V ₁ and V ₂ detected by the second motion vector detection circuit, respectively.
A selection switch for selecting and extracting any one of the two as the motion vector of the 2: 1 interlaced scanning signal; An image directionality detection circuit that generates a different logical output when it is determined that there is no difference in the amounts of the components and when it is determined that there is a difference in the amounts of the left and right diagonal components ; Connected to the motion vector detection circuit,
Detection error E ₁ and motion vector for motion vector V ₁
Receiving a detection error E ₂ for Le V _2, these false detection
An error comparison circuit that generates a different logical output depending on whether there is a difference between the differences E ₁ and E ₂ and a case where there is no difference , and receives a logic output from the image direction detection circuit and a logic output from the error comparison circuit, Based on these logic outputs
And an AND gate for controlling the selection switch , wherein the AND gate is connected to the image direction detection circuit by the image direction detection circuit.
There is no difference in the amount of left and right diagonal components in the image in the pixel block
Receives the corresponding logical output when it is determined that
Sagaa from the error comparison circuit to the detection error E ₁ and E ₂
The first operation is performed only when a logical output indicating that
The motion vector V ₁ output from the can vector detection circuit
Selection, otherwise the second motion vector detection
Select the motion vector V ₂ output from the output circuit
A motion vector detection device , wherein the selection switch is controlled. 6. The apparatus according to claim 5, wherein said first motion vector detection circuit is constituted by a circuit for detecting a motion vector that gives a minimum inter-field difference, and said second motion vector detection circuit is a minimum motion vector detection circuit. A motion vector detecting device comprising a circuit for detecting a motion vector that gives an inter-frame difference.