JPH10112845A - Interlace/sequential scanning conversion method for image signal and its circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce deteriorated image quality by generating an interpolation scanning line signal through in-field interpolation when a detection motion vector is in motion of horizontal panning. SOLUTION: A motion vector detection section 1 receiving an interlace scanning image signal S1 provides an output of a motion vector signal S2 for one frame. An image pattern detection section 2 detects a longitudinal/lateral pattern area from a horizontal/vertical high frequency component of the signal S1 to provide an output of an image pattern signal S3. A parameter setting section 3 sets an inter-frame interpolation filter mixing ratio 1-K and an in-field interpolation filter mixture rate K based on the signals S2, S3 to provide a output of a signal S4. A frame interpolation filter 4 and an in-field interpolation filter 5 generate interpolation signals S5, S6 based on each pass frequency characteristic. Coefficient weight sections 6-1, 2 multiply the signals S5, S6 with ratios 1-K, K respectively, the products are added by an adder section 7, which provides an output of a signal S7. A delay section 8 is used to adjust a delay in the processing time for the processing as above to provide an output of a signal S8. A multiplexer section 9 applies half compression to the signals S7, S8 with respect to a time base and conducts time division multiplex to obtain an image signal S9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing of scan conversion for converting an image signal of interlaced scanning into an image signal of progressive scanning. The present invention relates to an interlaced scan conversion method and circuit suitable for performing low scan conversion.

[0002]

2. Description of the Related Art Many image signals use interlaced scanning as a scanning mode. However, when this image signal is displayed on an image display unit for interlaced scanning, an interface disturbance such as line flicker occurs and the image quality deteriorates.

The interface interference can be eliminated by converting the image signal into a progressively scanned image signal by interlaced to sequential scan conversion and displaying the image signal in the form of progressive scan. A television receiver having this function has also been commercialized.

[0004] In the interlaced to sequential scan conversion, signal processing is performed to generate a signal of a scanning line lost in the interlaced scan by an interpolation process. This interpolation processing includes motion adaptive type and motion compensation type signal processing.

[0005] The former performs an interpolating process for changing a mixing ratio between inter-frame interpolation suitable for a still image region and intra-field interpolation suitable for a moving image region in accordance with image motion information. However, since the motion information is detected based on the magnitude of the difference signal between one frame, the motion information does not always correspond to the accurate motion of the image. For this reason, in the still image area, the interface disturbance can be completely removed, and a remarkable effect of improving the image quality can be obtained. However, in the moving image area, there is a problem that the removal of the interface interference is incomplete and the effect of improving the image quality is small.

On the other hand, the latter type of motion compensation detects the motion of an image as motion vector information, performs signal processing for motion compensation on signals in the preceding and succeeding fields with this motion vector information, and performs interpolation scanning. To generate a signal. With this method, it is possible to perform an interpolation process that substantially matches the motion of the image.
However, in order to perform accurate motion compensation signal processing, highly accurate detection of a motion vector is indispensable. For this reason, there is a problem that an enormous amount of signal processing is required.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and reduces unsightly image quality degradation by conventional motion adaptive interpolation and achieves motion compensation with a small amount of computation signal processing. An object of the present invention is to provide an interlaced to sequential scan conversion method and circuit having high image quality equivalent to that of the compensation type.

[0008]

In order to achieve the above object, the present invention employs the following technical means.

For interlaced image signals, a motion vector between frames of the image is detected, an image pattern of horizontal stripes and vertical stripes is detected, and inter-frame interpolation and intra-field interpolation are performed. The technical means for performing the scanning line interpolation is adopted.

In a region where the image pattern has a horizontal stripe pattern, when the motion vector is a vertical panning motion and the speed of the motion is lower than a set value, inter-frame interpolation is performed. In the area where the image pattern is a vertical stripe pattern, a signal of an interpolation scanning line is generated by intra-field interpolation when the motion vector is a horizontal panning motion. In accordance with the magnitude of the vector, the mixing ratio of the inter-frame interpolation and the intra-field interpolation is adaptively changed to generate an interpolated scanning line signal.

The effect of suppressing the deterioration of image quality achieved by the technical means will be described with reference to FIGS.

FIG. 12 is a schematic diagram of a signal spectrum in a horizontal, vertical and time three-dimensional frequency domain in horizontal pan and vertical pan movements. FIG. 9A shows the case of horizontal panning. In the stationary state, the component of the time frequency f is zero, and the signal spectrum exists on the μ-ν plane of the horizontal frequency μ and the vertical frequency ν. The image of the vertical stripe pattern is μ ≠ 0,
Since ν = 0, it has a signal spectrum on the μ axis of this μ-ν plane. On the other hand, in the movement of the horizontal pan, a signal spectrum exists on a plane indicated by a dot inclined by an angle θ with respect to the μ axis. The image of the vertical stripe pattern has components of time frequencies fa and fb. The angle θ is proportional to the pan speed, and the higher the speed, the larger the angle θ.

FIG. 1B shows the case of vertical panning. Since the image of the horizontal stripe pattern has μ = 0, ν ≠ 0, it has a signal spectrum on the ν axis of the μ-ν plane in a stationary state. on the other hand,
In the movement of the vertical pan, the signal spectrum exists on a plane indicated by a dot inclined by an angle θ with respect to the ν axis. The image of the horizontal stripe pattern has components of time frequencies fa 'and fb'. The angle θ is proportional to the pan speed, and the higher the speed, the larger the angle θ.

FIG. 13 is a schematic diagram showing a signal spectrum and an interpolation filter characteristic of a signal of the interlaced scanning system at the time of panning.

Scanning corresponds to a kind of sampling in the time, vertical domain. For this reason, this sampling frequency f _IS occurs on the f-ν plane of the time frequency f and the vertical frequency ν.
For example, the NTSC system (525 scanning lines, 60 fields)
(2: 1 interlaced scanning), as shown in FIG.
(30 Hz, 525/2 cpl) at the sampling frequency f
_IS occurs. Therefore, in the vertical stripe pattern during the horizontal panning motion, as shown in FIG. 3A, the signal spectrum of the original component starts from the origin and the signal spectrum of the folded component of the original signal starts from the sampling frequency f _IS. Occur. Also, in the horizontal stripe pattern during the vertical panning motion, a signal spectrum of the original component and the folded component is generated as shown in FIG.

The interpolation filter used for interlaced to sequential scan conversion removes aliasing components associated with interlaced scanning and performs processing for extracting only original components. And the frame
The inter-frame interpolation filter has a characteristic that the pass frequency ranges from time frequency 0 to f _C, and the in-field interpolation filter has a characteristic that the pass frequency ranges from 0 to ν _C.

FIG. 14 is a diagram showing the relationship between the interpolation filter during panning and the image quality obtained. Vertical stripe pattern during horizontal panning
When the pan speed is lower than VT, both the inter-frame interpolation and the intra-field interpolation extract only the original signal component (see FIG. 13 (a)). Good image quality is obtained without deterioration. If the pan speed exceeds VT, the intra-field interpolation extracts only the original signal component and thus the image quality is good. However, the inter-frame interpolation extracts the aliasing component and causes deterioration of the image quality. But,
As described above, in the present invention, in a region where the image pattern has a vertical stripe pattern, a signal of an interpolated scanning line is generated by intra-field interpolation at the time of horizontal panning, so that deterioration in image quality can be avoided.

In the horizontal stripe pattern at the time of vertical panning, when the pan speed is smaller than VT, only the original signal component is extracted by the inter-frame interpolation, so that a good image quality is obtained. In the interpolation, since the aliasing component is extracted, the image quality deteriorates (see FIG. 13B). If the pan speed exceeds VT, the intra-field interpolation extracts only the original signal component and thus the image quality is good. However, the inter-frame interpolation extracts the aliasing component and causes deterioration of the image quality. However, in the present invention, in the region where the image pattern is a horizontal stripe pattern, the interpolation scanning line is interpolated by inter-frame interpolation when the vertical pan movement speed is equal to or less than the set value VT, and by intra-field interpolation when the speed is above the set value VT. Since the signal is generated, deterioration of the image quality can be avoided.

As described above, the technical means of the present invention makes it possible to greatly reduce unsightly image quality deterioration due to horizontal panning and vertical panning movements, which has been caused by conventional motion adaptive interpolation. As a result, high image quality equivalent to that of the motion compensation type can be achieved.

Further, it is only necessary to detect the movement of the horizontal pan and the vertical pan, and it is not necessary to detect a highly accurate motion vector which is indispensable in the motion compensation type. In the case of an image signal that has been MPEG-encoded, which is an international standard for video encoding, it is also possible to detect horizontal pan and vertical pan movements by utilizing transmitted motion vector information.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described.
This will be described with reference to the block diagram of FIG. In the figure, 1 is a motion vector detecting section, 2 is an image pattern detecting section, 3 is a parameter setting section, 4 is an inter-frame interpolation filter, 5 is an intra-field interpolation filter, 6 is a coefficient weighting section, 7 Denotes an addition unit, 8 denotes a delay unit, and 9 denotes a multiplex unit.

The motion vector detecting section 1 detects a signal S2 of a motion vector for one frame from the interlaced image signal S1 by, for example, a block matching method.

The image pattern detecting section 2 detects the vertical stripe pattern and the horizontal stripe pattern of the image from the horizontal high-frequency component and the vertical high-frequency component of the image signal S1, and outputs the result to the image pattern signal S3. .

The parameter setting unit 3 calculates the motion vector signal S
2 and the image pattern signal S3, the value of the mixture ratio 1-K of the inter-frame interpolation filter and the value of the mixture ratio K of the in-field interpolation filter are set, and this mixture ratio is used as the signal S4. Output.

As shown in FIG. 13, the inter-frame interpolation filter 4 generates an interpolation signal S5 with frequency characteristics having a pass band of time frequencies 0 to f _C.

As shown in FIG. 13, the in-field interpolation filter 5 generates an interpolation signal S6 with a frequency characteristic having a pass band between vertical frequencies 0 to ν _C.

The coefficient weighting units 6-1 and 6-2 are respectively
Multiplication of interpolation signal S5 and mixing ratio 1-K, interpolation signal S6
Is multiplied by the mixing ratio K.

The adder 7 adds the two signals and outputs a signal S7 (S7 = S5５ (1-K) + S6 ・ K) of the interpolation scanning line.

The delay section 8 adjusts the time delay in the above signal processing, and outputs a signal S8 of the main scanning line.

The multiplexing unit 9 subjects the signal S8 of the main scanning line and the signal S7 of the interpolated scanning line to half-compression on the time axis and time-division multiplexing, and obtains a sequentially scanned image signal S9 at the output. .

The configuration and operation of each block will be described below.

FIG. 2 is a diagram showing an example of the configuration of the motion vector detecting section. The interlaced scanning image signal S1 and this signal
The signal S delayed by one frame period in the frame delay unit 10
10 is input to the block matching calculation unit 11. Then, signal processing according to the operation outline shown in FIG. 3 is performed. As shown in FIG. 3 (a), the signal S1 of the interlaced scanning is
Field 1 and field 2 constitute a frame. Therefore,
In the detection of the motion vector between one frame, the field 1
In the signal sequence of F1, F2, F3,... Separated by one frame period, and in field 2, F1 ′,
The signal sequence of F2 ', F3',... Is used. And FIG.
As shown in (b), in units of blocks (the block size is NN pixels × MM lines), the following is performed between the current block and search blocks 1,..., L in the search area one frame before. Is calculated. ES _J = Σ | S1 (X, Y) -S10 (X-Ndx, YM
dy) | where S1 (X, Y) is a pixel of the current block for which a motion vector is to be detected, and S10 (X-Ndx, Y-Mdy) is a position shifted Ndx in the horizontal direction and Mdy in the vertical direction from the current block. Indicates the pixel of the search block one frame before
| Indicates the sum of absolute values of the difference components at each pixel in the block.

FIG. 4 shows an example of a configuration for performing this calculation. The signal S10 one frame before the current signal S1 is input to the arithmetic units 14-1,. Each operation unit includes a subtraction unit 15, an absolute value conversion unit 16, and an accumulation unit 17, and performs the above-described operation on the pixels of the current block and the search block J (J = 1,..., L). ES _J to signal S1
Output as 1.

Returning to FIG. 2, the candidate vector detecting unit 12
The following operation is performed on the signal S11. MEB = MIN {ES _J , J = 1,..., L} Here, MIN {} indicates a search block in which the value of ES _J becomes minimum in the signal S11. Then, at the positions Ndx and Mdy of the search block, a candidate vector of the current block is generated as follows. V = V _MEB (V _X , V _Y ) where V _X = Ndx, V _Y = Mdy and outputs this as the candidate vector signal S13.

As shown in FIG. 3C, the motion vector setting unit 13 performs the following operation on the candidate vector V _I (I = 1,..., 9) of the current block and the neighboring reference blocks adjacent thereto. Do. VD = AVE {V _I , I = 1, ..., 9} or VD = MA
J {V _I , I = 1,..., 9} Here, AVE {} indicates an average, and MAJ {} indicates an operation of majority decision. The VD obtained by this operation is determined as the motion vector of the current block, and this is output as the signal S2.

In the detection of a motion vector, stationary, horizontal pan (V _X ≠ 0, V _Y = 0), vertical pan (V _X = 0, V _Y)
≠ 0) and other movements (V _X ≠ 0, V _Y ≠ 0) can be determined. Therefore, the number of search blocks and the detection accuracy can be reduced to about one-several number as compared with the motion vector detection of the motion compensation type, so that the circuit scale and the amount of calculation can be significantly reduced.

Next, FIG. 5 shows an example of the configuration of the image pattern detecting section. In FIG. 3A, the horizontal HPF 18 is a horizontal high-frequency component of the image signal S1, and the vertical HPF 19 is an image signal S1.
The vertical high frequency component of is extracted. In the smoothing unit 20, after the noise component is removed by the isolated point removal processing, the signal level is subjected to binary quantization of 0 if the signal level is within the set value ± TH and 1 if the signal level is equal to or more than the set value ± TH, and outputs binary signals S14 and S15. . As shown in FIG. 3B, the pattern judging section 21 outputs the binary signals S14 and S1.
From the form of 5, the flat part, the oblique stripe part, the vertical stripe part, and the horizontal stripe part
The type of image pattern is identified, and the pattern
Output to the signal S3.

Next, an outline of the operation of the parameter setting unit will be described with reference to FIG. The value of the mixture ratio K of the signal S4 is set according to the form of the motion vector signal S2 and the image pattern signal S3. That is, the signal S2 is V _X = 0, V _Y
= 0 (stationary), K = 0 (corresponds to inter-frame interpolation)
Set to. Signal S2 is _{V X ≠ 0, V Y =} 0 ( horizontal panning), when the signal S3 is 10 for (vertical stripes) is, K = 1 (Fi -
(Corresponds to interpolation within the field). When the signal S2 is V _X
= 0, V _Y ≦ VT (low-speed vertical pan), signal S3 is 01
In the case of (horizontal stripes), K = 0 is set. On the other hand, the signal S2 is V _X = 0, V _Y > VT (high-speed vertical pan), and the signal S3 is 0
At the time of 1 (horizontal stripe), K = 1 is set. Also, the signal S2
When V _X ≠ 0 and V _Y ≠ 0, a value from 0 to 1 is set as shown in the figure according to the magnitude of | V _X | + | V _Y |. As a result, K is set near 0 for low-speed motion, K is set near 0.5 for medium-speed motion, and K is set near 1 for high-speed motion. To realize a matched interpolation characteristic.

Next, the structure of the interpolation filter will be described with reference to FIG.
Will be described. In the figure, ○ indicates a signal of a scanning line transmitted by interlaced scanning, and ・ indicates a signal of an interpolated scanning line for conversion into sequential scanning. The inter-frame interpolation filter applies X = (A + B) / to the signals of the scanning lines A and B in the preceding and following fields.
2 is performed to generate an interpolated scanning line X having a frequency characteristic having a pass band of the time frequencies 0 to f _C shown in FIG. On the other hand, the intra-field interpolation filter responds to signals L-2, L-1, L1, L2,.
X = (L−1 + L1) / 2 or X = A1 · (L−
1 + L1) + A2 · (L−2 + L2) +... (However, ΔA
J = 0.5, J = 1, 2,...) To generate an interpolation scanning line X having a frequency characteristic having a pass band of the vertical frequency 0 to ν _C shown in FIG.

As described above, according to this embodiment, jump-to-sequential scan conversion with almost no unsightly image quality deterioration can be performed, and a remarkable improvement in image quality can be obtained.

Next, a second embodiment of the present invention will be described with reference to the block diagram of FIG. In this embodiment, one frame
This is suitable for simultaneously using a difference signal component between programs as motion information. In the figure, 1 is a motion vector detecting section, 2 is an image pattern detecting section, 23 is a parameter setting section, 4 is an inter-frame interpolation filter, 5 is an intra-field interpolation filter, 6 is a coefficient weighting section, 7 Is an adder, 8 is a delay, 9 is a multiplexor, 2
Reference numeral 2 denotes a motion information detection unit.

The motion vector detecting section 1 detects a signal S2 of a motion vector for one frame from the interlaced image signal S1 by, for example, a block matching method.

The image pattern detecting section 2 detects the vertical stripe pattern and the horizontal stripe pattern of the image from the horizontal high frequency component and the vertical high frequency component of the image signal S1, and outputs the result to the image pattern signal S3. .

The motion information detector 22 detects a motion information signal S20 from a difference signal component between one frame.

The parameter setting unit 23 calculates the mixing ratio 1-K of the inter-frame interpolation filter and the intra-field interpolation filter based on the motion vector signal S2, the image pattern signal S3 and the motion information signal S20. Is set, and this mixture ratio is output as a signal S4.

As shown in FIG. 13, the inter-frame interpolation filter 4 generates the interpolation signal S5 with a frequency characteristic having a pass band of time frequencies 0 to f _C.

As shown in FIG. 13, the intra-field interpolation filter 5 generates the interpolation signal S6 with a frequency characteristic having a pass band between the vertical frequencies 0 to ν _C.

The coefficient weighting units 6-1 and 6-2 respectively
Multiplication of interpolation signal S5 and mixing ratio 1-K, interpolation signal S6
Is multiplied by the mixing ratio K.

The adder 7 adds the two signals and outputs a signal S7 (S7 = S5５ (1-K) + S6 ・ K) of the interpolation scanning line.

The delay section 8 adjusts the time delay in the above signal processing, and outputs a signal S8 of the main scanning line.

The multiplexing unit 9 subjects the signal S8 of the main scanning line and the signal S7 of the interpolated scanning line to 1/2 compression on the time axis and time division multiplexing, and obtains the sequentially scanned image signal S9 at the output. .

Hereinafter, the configuration and operation of the motion information detecting section and the parameter setting section will be described. The other blocks have the same configuration as that of the first embodiment, and a description thereof will not be repeated.

FIG. 9 shows an example of the configuration of the motion information detecting section. An interlaced scan image signal S1 and a signal S10 obtained by delaying this signal by one frame delay by one frame delay unit 10.
Is input to the subtraction unit 24 to perform a subtraction operation on the two signals to extract a difference signal component between one frame. The quantization unit 25 quantizes the difference signal component in absolute value. This quantized signal is subjected to integration processing in the horizontal and vertical directions by the spatial integration unit 26 in order to reduce detection omission of motion information. Then, in the motion information setting unit 27, for example, 00 (signal value is zero), 01 (signal value is small), 10 (medium signal value), and 11 (signal value is large) in accordance with the value of the signal subjected to the integration processing. It outputs four types of motion information signals S20.

FIG. 10 is a schematic diagram of the operation of the parameter setting unit. The value of the mixing ratio K of the signal S4 is set according to the form of the motion vector signal S2, the image pattern signal S3, and the motion information signal S20. That is, when the signal S2 is V _X = 0,
When V _Y = 0 (stationary), K = 0 (corresponding to inter-frame interpolation). Signal S2 is _{V X ≠ 0, V Y =} 0 ( horizontal panning), when the signal S3 is 10 for (vertical stripes) is, K = 1 (Fi -
(Corresponds to interpolation within the field). When the signal S2 is V _X
= 0, V _Y ≤ VT (low-speed vertical pan), signal S3 is 01
In the case of (horizontal stripes), K = 0 is set. On the other hand, the signal S2 is _{V X = 0, V Y>} VT ( fast vertical panning), the signal S3 is 0
At the time of 1 (horizontal stripe), K = 1 is set. Also, the signal S2
When V _X ≠ 0 and V _Y ≠ 0, | V _X | + | V _Y | and the signal S
According to 20, the value from 0 to 1 is set as shown in FIG. That is, the signal S20 is changed to 10, 11 and 1 frame.
When the difference signal component between frames is large, the characteristic of the steep slope is set. When the signal S20 is 00, 01 and the difference signal component between one frame is small, the value of the mixing ratio K is set with the characteristic of a gentle slope. I do. Then, an interpolation characteristic matched to the motion of the image is realized.

As described above, according to the present embodiment, it is possible to perform jump-to-sequential scan conversion with almost no unsightly image quality deterioration, and a remarkable improvement in image quality can be obtained. In this embodiment, since the motion information is also used, the detection accuracy of the motion vector may be considerably low. For this reason, it is possible to realize the motion vector detection unit with a simpler configuration than in the first embodiment.

Next, a third embodiment of the present invention will be described with reference to FIG.
1 will be described with reference to a block diagram of FIG. This embodiment is suitable for performing scan conversion suitable for both a general image and a telecine image obtained by converting a film image into a video signal by pull-down processing. In the figure, 1 is a motion vector detecting unit, 2 is an image pattern detecting unit, 23 is a parameter setting unit, and 4 is a frame.
Inter-frame interpolation filter, 5 is an intra-field interpolation filter, 6
Is a coefficient weighting unit, 7 is an addition unit, 8 is a delay unit, 9 is a multiplexing unit,
37 is a film mode detecting section.

The motion vector detecting section 1 detects a signal S2 of a motion vector for one frame from the interlaced image signal S1 by, for example, a block matching method.

The image pattern detecting section 2 detects the vertical stripe pattern and the horizontal stripe pattern of the image from the horizontal high-frequency component and the vertical high-frequency component of the image signal S1, and outputs the result to the image pattern signal S3. .

The film mode detector 37 detects the period of the field where the difference signal component between one frame is zero. Then, when this cycle is not detected, it is determined as a general image, and when it is detected, it is determined as a telecine image. The reason is that, in a telecine image pulled down by 2: 3, a film image is composed of a signal of two field periods and a signal of three field periods, and in the three field period, one frame difference signal is used. There are fields where the component is zero. Moreover, this is because five fields are generated in a cycle. In the case of a telecine image, the frame sequence of the film image is detected based on the signal of the five field cycle. And
The result of the discrimination between the general image and the telecine image and the frame sequence of the film image are output as a signal FM. If the transmitting side also transmits the identification information of the film mode of the telecine image, the identification information is used to transmit the signal F.
It is also possible to generate M.

When the signal FM indicates a general image, the parameter setting unit 23 mixes the inter-frame interpolation filter based on the motion vector signal S2 and the image pattern signal S3 as in the above-described embodiment. The value of the ratio 1-K and the value of the mixture ratio K of the interpolation filter in the field are set, and this mixture ratio is represented by the signal S.
4 is output. On the other hand, when the signal FM indicates a telecine image, the value of the mixture ratio K is set to 0 so that the interpolation processing is performed using the same film image signal.

When the signal FM indicates a general image, the inter-frame interpolation filter 4 has an interpolated signal S5 having a frequency characteristic having a time band of 0 to f _C as a passband, as in the above-described embodiment.
Generate On the other hand, when the signal FM indicates a telecine image, an interpolation signal is generated according to the frame sequence of the film image. That is, in FIG. 7, when the current field and the previous field have the same frame sequence, the signal of the interpolation scanning line X is generated by the signal of the scanning line A. If the current field and the subsequent field have the same frame sequence, the signal of the interpolation scanning line X is generated by the signal of the scanning line B.

The in-field interpolation filter 5, as shown in FIG. 13, generates an interpolation signal S6 with a frequency characteristic having a pass band between vertical frequencies 0 to ν _C.

The coefficient weighting units 6-1 and 6-2 respectively
Multiplication of interpolation signal S5 and mixing ratio 1-K, interpolation signal S6
Is multiplied by the mixing ratio K.

The adder 7 adds the two signals and outputs a signal S7 (S7 = S5 (1-K) + S6.K) of the interpolation scanning line.

The delay section 8 adjusts the time delay in the above signal processing, and outputs a signal S8 of the main scanning line.

The multiplexing unit 9 subjects the signal S8 of the main scanning line and the signal S7 of the interpolation scanning line to 時間 compression on the time axis and time division multiplexing, and obtains a sequentially scanned image signal S9 at the output. .

Each block of the present embodiment can be realized by the same configuration as that of the first embodiment, and thus the description is omitted.

As described above, according to the present embodiment, there is almost no unsightly image quality degradation for general images, and it is possible to perform jump-to-sequential scan conversion with ideal characteristics for telecine images. As a result, a remarkable improvement effect can be obtained in improving the image quality. Note that the present embodiment can also be realized in a form in which motion information is used together as in the second embodiment.

Next, an embodiment in which the interlaced progressive scan conversion method and circuit of the present invention are applied to a television receiver will be described with reference to the block diagram of FIG.

[0070] base - video signal VS (interlaced scanning) of the baseband is the AD converter 28, the color subcarrier f _SC example 4
Sampling is performed at twice the sampling frequency and converted into a digital signal.

The three-dimensional YC separation unit 29 is a motion-adaptive 3D
The signal processing of dimensional luminance / color signal separation is performed, and the luminance signal Y
And a carrier chrominance signal C.

The color demodulation unit 30 synchronously detects the carrier chrominance signal C with the color sub-carrier f _SC and demodulates the color difference signals I and Q.

The luminance IP conversion section 31 performs signal processing of scan conversion from interlaced scanning to sequential scanning on the luminance signal Y, and generates a luminance signal YP for sequential scanning. This configuration is the same as in the first to third embodiments.

The color difference IP conversion section 32 performs signal processing for scan conversion from interlaced scanning to sequential scanning on the color difference signals I and Q, and generates a color difference signal CP for sequential scanning. Since the visual characteristics of the chrominance signal are inferior to those of the luminance signal, the signal of the interpolation scanning line is generated by the in-field interpolation filter.

The post-processing section 33 performs signal processing for various image quality improvements such as contour enhancement, black level correction, white level correction, and skin color correction, and signal processing for color space conversion.
The primary color RGB signal PV is output. Then, the display unit 34
Next, the signal PV is displayed in the form of sequential scanning.

The functions of each block excluding the luminance IP conversion unit and the function of converting a broadcast wave into a baseband video signal can be realized with the same configuration as that of a conventional television receiver, and therefore, the description is omitted. I do.

As described above, according to this embodiment, a television receiver that displays high-quality television images can be realized, and a remarkable effect on image quality improvement can be obtained.

Next, an embodiment in which the interlaced scanning conversion method and circuit of the present invention are applied to a digital broadcast receiver will be described with reference to the block diagram of FIG.

The digital broadcast wave VD is transmitted to the digital demodulation unit 3
5, a predetermined demodulation process (for example, PSK, QAM, CO
FDM, etc.) and a code error correction process to decode the bit stream signal DS.

The image decoding unit 36 performs a predetermined decoding process on the image data that has been MPEG-encoded, and outputs the decoded luminance signal Y and color difference signal C. In the MPEG encoding, DCT + MC predictive encoding is performed, so that image data also includes motion vector information necessary for decoding. Therefore, a decoded motion vector signal V is output.

The luminance IP conversion unit 31 has the same configuration as that of the first to third embodiments, and uses the motion vector signal V as a candidate vector, and performs signal processing for scan conversion from interlaced scanning to sequential scanning. To generate a luminance signal YP for sequential scanning.

The color difference IP conversion section 32 performs signal processing for scan conversion from interlaced scanning to sequential scanning on the color difference signals I and Q, and generates a color difference signal CP for sequential scanning. Since the visual characteristics of the chrominance signal are inferior to those of the luminance signal, the signal of the interpolation scanning line is generated by the in-field interpolation filter.

The post-processing section 33 performs signal processing for various image quality improvements such as contour enhancement, black level correction, white level correction, and skin color correction, and signal processing for color space conversion.
The primary color RGB signal PV is output. Then, the display unit 34
Next, the signal PV is displayed in the form of sequential scanning.

As described above, according to the present embodiment, a digital broadcast receiver for displaying a high-quality television image can be realized, and a remarkable effect on image quality improvement can be obtained. Further, since the motion vector information transmitted by digital broadcasting is used as a motion vector signal required for interlaced to sequential scan conversion, the circuit scale can be reduced.

[0085]

According to the present invention, image quality deterioration which is difficult to avoid with the prior art is almost eliminated, and jump-to-sequential scan conversion can be realized with almost ideal characteristics. For this reason, a remarkable effect of improving the image quality of the television image can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a motion vector detection unit.

FIG. 3 is an operation schematic diagram of motion vector detection.

FIG. 4 is a diagram illustrating a configuration example of a block matching calculation unit.

FIG. 5 is a diagram illustrating a configuration example of an image pattern detection unit.

FIG. 6 is an operation schematic diagram of a parameter setting unit.

FIG. 7 is a schematic diagram of an interpolation filter.

FIG. 8 is a block diagram of a second embodiment of the present invention.

FIG. 9 is a diagram illustrating a configuration example of a motion information detection unit.

FIG. 10 is an operation schematic diagram of a parameter setting unit.

FIG. 11 is a block diagram of a third embodiment of the present invention.

FIG. 12 is a schematic diagram of a signal spectrum during horizontal pan and vertical pan movements.

FIG. 13 is a schematic diagram of a signal spectrum of an interlaced scanning system during a panning motion and an interpolation filter characteristic.

FIG. 14 is a diagram illustrating the relationship between an interpolation filter and image quality during a panning motion.

FIG. 15 is a diagram showing an embodiment applied to a TV receiver.

FIG. 16 is a diagram showing an embodiment applied to a digital broadcast receiver.

[Explanation of symbols]

1: a motion vector detecting section, 2: an image pattern detecting section,
3, 23: parameter setting unit, 4: inter-frame interpolation filter, 5: inter-field interpolation filter, 6: coefficient weighting unit,
7 ... addition unit, 8 ... delay unit, 9 ... multiplex unit, 10 ... 1 frame
Delay unit, 11: block matching calculation unit, 12: candidate vector detection unit, 13: motion vector setting unit, 14 ...
Arithmetic units, 15, 24 subtraction unit, 16 absolute value conversion unit, 17 integration unit, 18 horizontal HPF, 19 vertical HP
F, 20: smoothing section, 21: pattern determining section, 22: motion information detecting section, 25: quantizing section, 26: spatial integrating section, 2
7: motion information setting unit, 28: AD conversion unit, 29: three-dimensional YC separation unit, 30: color demodulation unit, 31: luminance IP conversion unit,
32: color difference IP conversion unit, 33: post-processing unit, 34: display unit, 35: digital demodulation unit, 36: image decoding unit, 37 ...
Film mode detector.

Continued on the front page (72) Inventor Masato Sugiyama 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the multimedia system development headquarters of Hitachi, Ltd. (72) Inventor Nobufumi Nakagaki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Visual Information Media Division

Claims (12)

[Claims] An interlaced progressive scan conversion method for converting an interlaced scan image signal into a progressive scan image signal by signal processing of scanning line interpolation. A motion vector is detected, and an image pattern of horizontal stripes and vertical stripes is detected. In an area where the detected image pattern is a horizontal stripe pattern, the detected motion vector is a vertical panning motion and a motion speed is predetermined. When the detected motion vector is a vertical pan motion and the speed of the motion is equal to or higher than the threshold value, an interpolated scanning line is generated by inter-frame interpolation. Of the detected image pattern
In an area having vertical stripes, when the detected motion vector is a horizontal panning motion, an interpolated scanning line signal is generated by intra-field interpolation. 2. If the detected motion vector is neither a vertical pan nor a horizontal pan motion, the mixture ratio of inter-frame interpolation and intra-field interpolation is determined according to the magnitude of the detected motion vector. 2. The method according to claim 1, wherein the signal of the interpolated scanning line is generated by adaptively changing. 3. An interlaced progressive scan conversion method for converting an interlaced scan image signal into a progressive scan image signal by signal processing of scanning line interpolation. A motion vector is detected, an image pattern of horizontal stripes and vertical stripes is detected, and motion information of an image is detected based on the presence or absence of an inter-frame difference signal component. In the region where the detected image pattern has a horizontal stripe pattern, When the detected motion vector is a vertical pan motion and the speed of the motion is equal to or less than a predetermined threshold, an interpolated scanning line signal is generated by inter-frame interpolation, and the detected motion vector is a vertical pan motion and When the motion speed is equal to or higher than the threshold value, an interpolated scanning line signal is generated by intra-field interpolation. In the region where the detected image pattern is a vertical stripe pattern, the detected motion vector is horizontally panned. In the case of motion, a signal of an interpolated scanning line is generated by intra-field interpolation. If the detected motion vector is not a vertical pan or horizontal pan motion, inter-frame interpolation and intra-field interpolation are performed. An interlaced progressive scan conversion method of an image signal, wherein a signal of an interpolated scan line is generated by adaptively changing a mixing ratio according to the magnitude of the detected motion vector and the magnitude of the detected motion information of the image. . 4. A block matching method in which a block of N pixels × M lines is used as a unit when detecting the motion vector, or a block in which motion vector information in a macro block unit in motion compensation prediction coding is used as a candidate vector. 4. The method according to claim 1, wherein a matching method is used. 5. In the case where the image signal is a telecine image signal obtained by converting a film image into a video signal by pulling down a film image, in the same film frame period, one film within the film frame period is used. 5. The method according to claim 1, wherein an interpolated scanning line signal is generated by an interlaced scanning signal before or after one field. 6. An image display section having a function of displaying an image in the form of a progressive scan, wherein the interlaced progressive scan conversion method according to claim 1 converts an interlaced scan image signal into a progressively scanned image signal. A television receiver, which performs scan conversion. 7. An interlaced progressive scan conversion circuit for converting an interlaced scan image signal into a progressive scan image signal by signal processing of scanning line interpolation, wherein the inter-frame motion of the image is based on the interlaced scan image signal. A motion vector detecting means for detecting a vector, an image pattern detecting means for detecting an image pattern of horizontal stripes and vertical stripes based on the image signal of the interlaced scanning, and a signal of an interpolation scanning line from the image signal of the interlaced scanning. Interpolated scanning line generating means for generating, and multiplexing means for time-division multiplexing the interpolated scanning line signal from the interpolated scanning line generating means and the interlaced scanning image signal to output a sequentially scanned image signal, The detection result by the image pattern detection means indicates a horizontal stripe, and the detection result by the motion vector detection means is a vertical pan movement and the movement speed is a predetermined movement. If the value is less than or equal to the value, the interpolated scanning line generating means generates a signal of the interpolated scanning line by inter-frame interpolation, the detection result by the image pattern detecting means shows horizontal stripes, and the motion vector detecting means In the case where the detection result in the above is a vertical pan movement and the movement speed is equal to or higher than the threshold value, the interpolation scanning line generation means generates an interpolation scanning line signal by intra-field interpolation, and the image pattern detection means In the case where the detection result in (1) indicates vertical stripes and the detection result in the motion vector detection means indicates a horizontal panning motion, the interpolation scanning line generation means generates an interpolation scanning line signal by intra-field interpolation. An interlaced progressive scan conversion circuit for an image signal. 8. If the detection result of said motion vector detecting means does not indicate any of vertical panning and horizontal panning, said interpolated scanning line generating means performs inter-frame interpolation and intra-field interpolation. 8. The interlaced progressive scan conversion circuit according to claim 7, wherein the interpolated scanning line signal is generated by adaptively changing the mixing ratio of the motion vector according to the magnitude of the motion vector. 9. An interlaced progressive scan conversion circuit for converting an interlaced scan image signal into a progressive scan image signal by signal processing of scanning line interpolation, wherein the inter-frame motion of the image is performed based on the interlaced scan image signal. Motion vector detecting means for detecting a vector, image pattern detecting means for detecting an image pattern of horizontal stripes and vertical stripes based on the image signal of the interlaced scanning, and inter-frame detection based on the image signal of the interlaced scanning. Motion information detecting means for detecting motion information of an image based on the presence or absence of a difference signal component; interpolated scanning line generating means for generating an interpolated scanning line signal from the interlaced scanning image signal; and interpolation from the interpolated scanning line generating means. A multiplexing unit that time-division multiplexes the signal of the scanning line and the image signal of the interlaced scanning and outputs an image signal of the sequential scanning; Kicking detection result indicates horizontal stripes, and,
If the result of the detection by the motion vector detecting means is a vertical pan movement and the speed of the movement is below a predetermined threshold, the interpolated scanning line generating means generates an interpolated scanning line signal by inter-frame interpolation. When the detection result of the image pattern detection means indicates a horizontal stripe, and the detection result of the motion vector detection means indicates a vertical pan movement and the speed of the movement is equal to or higher than the threshold, the interpolation scanning line generation means Generates a signal of an interpolated scanning line by intra-field interpolation, and the detection result of the image pattern detecting means indicates a vertical stripe, and the detection result of the motion vector detecting means indicates a horizontal pan movement. The interpolated scanning line generating means generates an interpolated scanning line signal by intra-field interpolation. Or if not even show any movement of the horizontal pan, said interpolated scan line generating means, frame -
It is characterized in that a signal of an interpolated scanning line is generated by adaptively changing a mixture ratio of inter-frame interpolation and intra-field interpolation according to the magnitude of the motion vector and the magnitude of the motion information of the image. An interlaced progressive scan conversion circuit for image signals. 10. The motion vector detecting means comprises N pixels ×
The motion vector is detected using a block matching method using a block of M lines as a unit or a block matching method using a motion vector information in a macroblock unit as a candidate vector in the motion compensation prediction coding. 10. The interlaced progressive scan conversion circuit for image signals according to 7 to 9. 11. When the image signal is a telecine image obtained by converting a film image into a video signal by performing a pull-down process, the interpolation scanning line generating means may use the same film frame.
7. A signal for an interpolated scanning line is generated by an interlaced scanning signal one field before or one field in the film frame period during the frame period.
2. The interlaced progressive scan conversion circuit for image signals described in 0. 12. The image display section has a function of displaying an image in the form of progressive scanning, and the interlaced progressive scan conversion circuit according to claim 7 converts the interlaced scanning image signal to the progressively scanned image signal. A television receiver, which performs scan conversion.