JPH09284729A - Image edge detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an edge in a moving area at a low sensitivity in addition to edge detecting over a wide band in a still image area. SOLUTION: Two or over of a prescribed number of frames consisting of picture elements of sampling patterns different from each frame obtained by applying offset-sampling to an image between frames are used for one unit. An image signal subject to band compression with the repeated units is used and an inter-frame interpolation circuit 11 is used to interpolate the image signal to generate an interpolated image signal. An edge detection means 12 detects the edge signal of the generated image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image edge detecting device for detecting edges of an image band-compressed by subsampling.

[0002]

2. Description of the Related Art In general motion area detection (also referred to as motion detection), a portion having a large absolute value of a calculated frame difference is determined as a motion area. If motion detection is simply performed using the frame difference, (1) noise may cause malfunction, or (2) the frame difference may become too large (the sensitivity becomes too high at the image edge portion). Non-linear processing is used to prevent (1) above, and (2) above
The overall sensitivity is adjusted by dividing the absolute value of the frame difference signal at the separately extracted image edge portion. The edge detection device used in this type of motion detection uses the edge only in the current field.

In the high-definition broadcasting system MUSE, the sampling pattern is constructed so as to make a cycle of four fields as shown in FIG. 17, but points indicated by X in FIG. 17 are not transmitted. That is, since the transmitted data is thinned out every other point by sub-sampling, the data is missing and the edge of the high frequency band cannot be obtained originally.
In an inter-frame interpolated image that is interpolated using two field images composed of pixels spatially displaced by inter-frame offset sub-sampling, adjacent pixels are pixels that are temporally displaced. Therefore, conventionally, the inter-frame interpolated image is considered to be affected by the motion and is not used for the edge detection, and the edge detection is performed for the sample in the same field where there is no room for the influence of the motion. .

However, when only the data of the current field is used, as can be seen from FIG. 17, the edges can be detected only every other point, and the data array of the current field is a five-point grid. Therefore, for edge detection, a method of two-dimensionally expanding and performing spatial interpolation is generally used. The edge obtained from such a spatially interpolated image does not have a sufficient band in the stationary portion, and the detection sensitivity of the edge of the moved portion is the same as the sensitivity of the stationary portion.
Further, in the image edge detection device for motion detection, it is impossible in principle to distinguish a still part and a moving part and perform separate processing, and therefore, the edge detection sensitivity has always been fixed.

[0005]

As described above, as a measure for preventing the sensitivity of the image edge portion from becoming too high and the fluctuation of the edge component being detected as a frame difference and being falsely detected as an unnecessary motion, As shown in 16,
It is known that the image edge signal extracted separately is used to divide the absolute value of the frame difference signal to adjust the overall detection sensitivity. However, if the edge detection sensitivity is adjusted as a whole in this way, the edge detection band is narrow in the static or near static area. Will be detected as enlarged. Further, even if the edge slightly moves in the still portion, the motion detection is performed, the still image processing is switched to the moving image processing, and the edge becomes unstable due to blurring or crisping. On the other hand, in the moving part, when the edge part is subjected to the still image processing, the multiple lines are folded back.

For this reason, the edge detection sensitivity is adjusted to be high in the still portion so that the motion detection sensitivity of the still portion is lowered.

It is an object of the present invention to provide an edge detecting device capable of detecting an edge in a wide band in a stationary area and detecting an edge in a moving area with low sensitivity.

[0008]

[Means for Solving the Problems]

1) An image edge detecting apparatus according to the present invention is a field obtained by offset sub-sampling an image between fields or frames, or a predetermined number of two or more fields composed of pixels having different sampling patterns for each frame. Alternatively, an interpolation image generation in which a frame is set as one unit and interpolation is performed using a plurality of consecutive odd or even fields of a band-compressed input image signal or a plurality of consecutive frames to generate an interpolated image signal Means and an edge detecting means for detecting an edge signal of the image generated by the interpolated image generating means.

2) The image edge detecting apparatus according to the present invention is
A band in which two or more predetermined numbers of fields or frames configured by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames are set as one unit, and the units are repeated. Interpolated image generating means for generating an interpolated image signal by interpolating using a plurality of consecutive odd or even fields of the compressed input image signal or a plurality of consecutive frames, and the interpolated image generating means. And a non-recursive temporal filter that adds two temporally consecutive interpolated images at a predetermined ratio and outputs the result, and an edge detection unit that detects an edge signal of the image from the non-recursive temporal filter. It is characterized by

3) The image edge detecting device according to the present invention is
A band in which two or more predetermined numbers of fields or frames configured by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames are set as one unit, and the units are repeated. Interpolated image generating means for generating an interpolated image signal using a plurality of consecutive odd or even fields of the compressed input image signal or a plurality of consecutive frames, and an input from the interpolated image generating means A recursive temporal filter that adds a signal and a recursive input at a predetermined ratio and outputs the delayed signal, and delays the output by the time corresponding to the interpolated image to be the recursive input; and the recursive temporal filter. Edge detection means for detecting an edge signal of the image.

4) The image edge detecting device according to the present invention is
A band in which two or more predetermined numbers of fields or frames configured by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames are set as one unit, and the units are repeated. Edge detection means for detecting an edge signal of the compressed input image signal and edge signals corresponding to two temporally consecutive image signals detected by the edge detection means are added at a predetermined ratio and output. And a non-recursive temporal filter.

5) The image edge detecting device according to the present invention is
A band in which two or more predetermined numbers of fields or frames configured by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames are set as one unit, and the units are repeated. An edge detecting means for detecting an edge signal of the compressed input image signal, an edge signal detected by the edge detecting means and a recursive input are added at a predetermined ratio and output, and the output is output to the image signal. A cyclic temporal filter that delays by a corresponding time and is used as the recursive input is provided.

6) The image edge detecting device according to the present invention is
A band in which two or more predetermined numbers of fields or frames configured by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames are set as one unit, and the units are repeated. Interpolated image generating means for generating an interpolated image signal by interpolating using a plurality of consecutive odd or even fields of the compressed input image signal or a plurality of consecutive frames, and the interpolated image generating means. A two-dimensional or one-dimensional calculation in which the value of the central pixel is calculated by multiplying each of the pixels included in a two-dimensional or one-dimensional fixed range centered on the processing target pixel by a predetermined coefficient -Dimensional low-pass filter and edge detection means for detecting an edge signal of an image from the low-pass filter Characterized by comprising a.

7) The image edge detecting apparatus according to the present invention is
A band in which two or more predetermined numbers of fields or frames configured by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames are set as one unit, and the units are repeated. Edge detection means for detecting an edge signal of a compressed input image, the edge detection means varying output gain, and the motion detection means for detecting a motion of the input image based on the input image signal, On the basis of the detection result, there is provided motion detection means for reducing the output gain of the edge detection means in the moving area and increasing the output gain of the edge detection means in the stationary area.

8) The image edge detecting apparatus according to the present invention is
In the image edge detecting device described in the above 7), the motion detecting means is configured so that the absolute value of a difference signal between two consecutive odd or even fields of the input image signal whose sampling patterns match or between two consecutive frames. And a space for spatially interpolating the absolute value of the difference signal calculated by the calculating means to generate a difference signal at a non-sampling point and outputting the difference signal together with the absolute value of the difference signal. The interpolation filter and the difference signal subjected to the interpolation from the spatial interpolation filter are compared with a predetermined threshold for each detection region having a predetermined size, and the interpolation is performed. When the difference signal is smaller than the threshold value, a control signal for increasing the output gain of the edge detecting means is output, and in other cases, the output gain of the edge detecting means is lowered. Characterized in that it comprises a threshold processing circuit for outputting a control signal to.

9) In the image edge detecting apparatus according to any one of 1) to 3) or 6), the interpolated image generating means is provided with a delay time corresponding to the field or frame signal forming the unit. One delay circuit for delaying the input image signal of the edge detecting means,
The input image signal and the image signal from the delay circuit are alternately switched at the timing of the offset sub-sampling between the fields or frames, and a plurality of consecutive fields or frames of the input image signal are used for internal switching. And a switching circuit for generating the inserted interpolated image signal and outputting the generated interpolated image signal to the edge detecting means.

10) In the image edge detecting device according to any one of 1) to 3) or 6), the interpolated image generating means is provided with a delay time corresponding to the field or frame signal constituting the unit. The input image signal is obtained by alternately switching one delay circuit that delays the input image signal, the input image signal, and the image signal from the delay circuit at the timing of the offset subsampling between the fields or frames. A switching circuit for generating an interpolated image signal interpolated using a plurality of consecutive fields or frames of a signal, wherein one switching circuit outputs a switching output of the switching circuit to the delay circuit and edge detection means. It is characterized by including and.

11) In the image edge detecting device as described in any one of 1) to 3) or 6), the interpolated image generating means is provided with a delay time corresponding to the field or frame signal constituting the unit. First to n-th (n ≧ 1) delay circuits for delaying the input image signal, a delay circuit group in which the first to n-th delay circuits are connected in series, and a first circuit for interpolating the input image signal An interpolated image generating means, which has the delay circuit and the switching circuit described in 9) and outputs to the edge detecting means, and the image signals from the first to n-th delay circuits. (N + 1) th interpolated image generating means for interpolating the (n + 1) th interpolated image, and including (n + 1) th interpolated image generating means for outputting to the edge detecting means, the delay circuit having the delay circuit and the switching circuit described in 9) above. Characterized by .

12) In the image edge detecting apparatus according to any one of 1) to 3) or 6), the interpolated image generating means is provided with a delay time corresponding to the field or frame signal constituting the unit. First to m-th (m ≧ 1) delay circuits for delaying the input image signal, wherein a delay circuit group in which the first to m-th delay circuits are connected in series, and a first circuit for interpolating the input image signal An interpolated image generating means, which has the delay circuit and the switching circuit according to the above 10) and outputs to the edge detecting means, and the image signals from the first to mth delay circuits. (M + 1) th interpolated image generating means for interpolating
The delay circuit according to the above 10) and a (m + 1) th interpolated image generating means for outputting to the edge detecting means having a switching circuit are included.

[0020]

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

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
An embodiment will be described. In FIG. 1, reference numeral 11 denotes an interframe interpolating circuit, which has a switch 100 that is switched at sub-sampling timing, and a 1-frame delay circuit 101 that delays the MUSE signal obtained through the switch 100 by 1 frame. , The current field data,
The data is interpolated (interpolation between frames) with the data of the field one frame before, which is delayed by one frame by the one-frame delay circuit 101. The sampling points are arranged as shown in FIG. 2. The black circles shown in FIG. 2 are the sampling points of the current field, and the white circles are the sampling points of the field one frame before. These fields correspond to, for example, the 4nth field and the 4n + 2nd field in FIG.
Reference numeral 12 denotes an edge detection means, which is an interframe interpolation circuit 11
Is used to detect edges from the data interpolated between frames, and a method similar to the conventional method is used for edge detection.

As described above, in an inter-frame interpolated image interpolated using two field images composed of pixels spatially displaced by inter-frame offset sub-sampling, adjacent pixels are temporally displaced. Conventionally, it has been considered that interframe interpolated images cannot be used for edge detection, and edges were used only in the same field. However, the number of samples in the same field is 1.
It can be detected only by the difference between the points (see Fig. 2).
Therefore, the band of the edge was narrower and half as compared with the case where it was detected by the signal before sub-sampling.

On the other hand, when the inter-frame interpolation circuit 11 interpolates between frames, the edge detection means 12 uses the sample points indicated by black circles and open circles for edge detection, as shown in FIG. The number of sample points is doubled as compared with the conventional example (see FIG. 2) using sample points in the same field, and therefore the detection band is doubled.

Therefore, in a stationary or near stationary portion, a wide band edge can be detected, and motion detection due to a slight movement of the edge can be suppressed. When there is motion, the correlation between frames disappears, and the edge signal obtained by interpolating between frames becomes a signal close to the signal obtained by adding the edge signals for two frames, and the edge signal was affected by the motion. It will be unnatural. However, since the edge signal is not continuous between the adjacent samples due to the movement, it becomes difficult to detect the edge, and as a result, the edge detection sensitivity decreases. Therefore, even when the wide-band edge detection is performed, the motion detection sensitivity does not unnecessarily decrease in the moving area. In this way, even if there is an influence of the motion, if the influence is not a problem, the sample points of the adjacent frames can be added to the edge detection target.

<Second Embodiment> FIG. 4 shows a second embodiment of the present invention.
An embodiment will be described. This embodiment is different from the first embodiment in the configuration of the interframe interpolation circuit. That is, the inter-frame interpolation circuit 11 according to the first embodiment has the switch 100 that is switched at the sub-sampling timing and the M obtained through the switch 100.
A 1-frame delay circuit 101 for delaying the USE signal by 1 frame is provided, and the current field data and the 1-frame-preceding field data delayed by 1 frame by the 1-frame delay circuit 101 are sequentially edged. It was designed to send it to the detection means 12. On the other hand, the inter-frame interpolation circuit 41 according to the present embodiment delays the input MUSE signal by one switch and the switch 400 that is switched at the sub-sampling timing.
The frame delay circuit 401 is provided, and the data of the current field and the data of the field one frame before which is delayed by one frame by the one frame delay circuit 401 are switched by the switch 400 at the sub-sampling timing and are obtained ( The data (interpolated between frames) is sequentially sent to the edge detecting means 12.

The inter-frame interpolation operation in this embodiment is
Since it is essentially the same as the interframe interpolation operation in the first embodiment, the description thereof is omitted.

<Third Embodiment> FIG. 5 shows a third embodiment of the present invention.
An embodiment will be described. This is, for example, 4 shown in FIG.
This is an example in which interpolation is performed using two field signals to widen the band of edge detection. In FIG. 5, reference numeral 51 denotes an interframe interpolating circuit, which is composed of a switch 510 and a one-frame delay circuit 511, and has the same function as the interframe interpolating circuit 11 shown in FIG. 1, for example, an odd field of the MUSE signal. Is interpolated between frames. Reference numeral 52 is a one-field delay circuit, which delays the input MUSE signal by one field. Reference numeral 53 denotes an inter-frame interpolation circuit, which is composed of a switch 530 interlocking with the switch 510 and a 1-frame delay circuit 531 and has the same function as the inter-frame interpolation circuit 51. A field delayed by an amount, that is, an even field is interpolated between frames. Reference numeral 54 is an edge detecting means, which detects an edge based on the interpolated data supplied in parallel from the inter-frame interpolating circuits 51 and 53.

In the present embodiment, the four fields of FIG. 17 are used to generate the interpolated data of the odd field and the even field, and the interpolated data are sent to the edge detecting means 54 in parallel. Since the edge detection operation is essentially the same as that of the above embodiment, the description thereof will be omitted.

<Fourth Embodiment> FIG. 6 shows a fourth embodiment of the present invention.
An embodiment will be described. Compared to the third embodiment, this embodiment is different in the configuration of the interframe interpolation circuit for interpolating the even and odd fields of the MUSE signal. That is, the interframe interpolation circuits 51 and 53 according to the third embodiment have essentially the same functions as the interframe interpolation circuit 11 according to the first embodiment. On the other hand, the interframe interpolation circuits 61 and 63 according to this embodiment have essentially the same functions as the interframe interpolation circuit 41 according to the second embodiment.

Therefore, the operation of the interframe interpolating circuits 61 and 63 according to the present embodiment is essentially the same as the operation of the interframe interpolating circuits 51 and 53 according to the third embodiment. Is omitted.

<Fifth Embodiment> FIG. 7 shows a fifth embodiment of the present invention.
An embodiment will be described. 7, 11 and 12 are shown in FIG.
The same parts are shown. 71 is a temporal filter,
The wideband edge signal from the edge detection means 12 is subjected to temporal filter processing. The temporal filter 71 is preferably the recursive filter shown in FIG. 8 or the non-recursive filter shown in FIG. 9. The delay circuit shown in FIGS. 8 and 9 may be a one-frame delay circuit or a one-field delay circuit. good. Further, 41 interframe interpolating circuits may be used instead of 11.

In the present embodiment, since the edge signal from the edge detecting means 12 is subjected to the temporal filter processing, the still edge is left as it is, the edge level is lowered when the edge is moved, and the edge level is changed according to the movement. Can be changed.

Such an effect can also be obtained by performing a temporal filter process on the edge signal from the edge detecting means 54 of the image edge detecting apparatus shown in FIGS. 5 and 6 by the temporal filter 71 shown in FIG.

<Sixth Embodiment> FIG. 10 shows a sixth embodiment of the present invention. The present embodiment is different from the fifth embodiment in the configuration. That is,
In the fifth embodiment, the interframe interpolation circuit 11 interpolates between frames, and based on the interpolated data, the edge detection means 12 predicts an edge signal to detect an edge, and the edge detection means. The edge signal from 12 is temporally filtered by the temporal filter 71. On the other hand, in the present embodiment,
The inter-frame interpolation circuit 11 interpolates between frames, the inter-frame interpolated data is subjected to temporal filter processing by the temporal filter 81, and the edge signal is detected by the edge detection means 82 based on the obtained signal. . As the temporal filter 81, the recursive filter shown in FIG. 8 and the non-recursive filter shown in FIG. 9 are preferable. Instead of 11, 41 inter-frame interpolation circuits may be used.

Therefore, the present embodiment can exhibit the same effects as the effects of the fifth embodiment.

Such an effect is shown in FIG. 10 after the interpolation data from the inter-frame interpolation circuits 51 and 53 of the image edge detecting device shown in FIG. 5 is temporally filtered by the temporal filter 81 shown in FIG. It can also be achieved by detecting the edge signal by the edge detecting means 82 shown. The same effect is obtained by subjecting the interpolated data from the inter-frame interpolating circuits 61 and 63 of the image edge detecting device shown in FIG. 6 to temporal filter processing by the temporal filter 81 shown in FIG. Even if the edge signal is detected by 82, it can be performed.

<Seventh Embodiment> FIG. 11 shows a seventh embodiment of the present invention. Compared with the sixth embodiment, the present embodiment is different in configuration. That is, the sixth
In the embodiment, the edge signal is the interframe interpolation circuit 1
1 has been used to widen the band, but in the present embodiment, the edge detection means 1101 detects the edge signal from the image signal band-compressed by the sub-sampling (not wide band).
Then, the detected edge signal is subjected to temporal filter processing by the temporal filter 1102. Therefore, the effects of this embodiment are essentially the same as the effects of the sixth embodiment.

<Eighth Embodiment> FIG. 12 shows an eighth embodiment of the present invention. In FIG. 12, 11 shows the same part as FIG. 121 is a two-dimensional LPF (low pass filter)
er), which performs filtering between frames. Reference numeral 122 denotes an edge detecting means, which is a two-dimensional LPF 12
The edge is detected from the signal from 1.

After the inter-frame interpolation by the inter-frame interpolation circuit 11, the two-dimensional filter 121 performs the inter-frame filter processing, so that the bandwidth of the edge detection is widened and the detection edge sensitivity due to the motion is controlled. be able to. Here, the temporal effect is obtained by adding inter-frame filter processing such as a two-dimensional filter instead of simple inter-frame nesting before inter-frame interpolation before obtaining edge signals. When an edge is taken from such inter-frame temporally interpolated signals, the edge can be obtained from twice the sample points in the stationary portion.
Broadband edge detection similar to that of the embodiment can be realized. On the other hand, when moving, an edge reduced by the interpolation coefficient is obtained, and the same effect as that of the fifth and sixth embodiments can be obtained.

FIG. 13 shows 3 × 3 as a two-dimensional LPF 121.
The relation between the calculation region and the coefficient of the 3 × 3 two-dimensional LPF in the case of using the two-dimensional LPF is shown. For the filter coefficients shown in FIG. 13, α ₀ = (1/4), α ₁ = (1/8), α ₂ =
If it is set to (1/16), the value of the central pixel is the result of weighted addition with the coefficient corresponding to each pixel, so the gain of the moved edge is reduced to 1/4, and the gain of the edge of the stationary portion is 1. Become.

<Ninth Embodiment> FIG. 14 shows a ninth embodiment of the present invention. This is an example in which the edge detection sensitivity is controlled by a separately provided simple motion detection circuit.
In FIG. 14, reference numeral 140 denotes an edge detecting means, which is composed of an edge detecting circuit 1401 and a gain controller 1402. The edge detecting circuit 1401 detects an edge based on the input MUSE signal, and the gain controller 1402. Is edge detection means 14
It controls the gain of 0. The edge detection used here may be the method according to the eighth embodiment, the method according to the first, fifth, and sixth embodiments, or a combination of the methods.

Reference numeral 141 denotes a simple motion detection circuit, which is a 2-frame delay circuit 1410, a subtraction circuit 1411 and an ABS.
A circuit 1412, a switch 1413, a spatial interpolation filter 1414, and a threshold processing circuit 1415 are included. The 2-frame delay circuit 1410 outputs the input MUSE signal to 2
The frame is delayed. The subtraction circuit 1411 outputs the MUSE signal and the 2-frame delay circuit 1410
The difference is two frames from the MUSE signal delayed by the number of frames. The ABS circuit 1412 is a subtraction circuit 141.
It takes the absolute value of the difference of 2 frames from 1. The switch 1413 switches at sub-sample timing. The spatial interpolation filter 1414 spatially interpolates the non-sample points. Threshold processing circuit 14
Reference numeral 15 denotes a threshold value process for each detection area having a predetermined size.

The operation will be described. MUSE signal and M delayed by 2 frames by the 2 frame delay circuit 1410
The USE signal is subtracted by the subtraction circuit 1411 to obtain AB
The S circuit 1412 takes the absolute value of the difference between the two frames. The absolute value is passed through the switch 1413 that is switched at the sub-sample timing, and the spatial interpolation filter 14
The non-sample points are spatially interpolated by the spatial interpolation filter 1414. Next, the threshold value processing circuit 1415 compares the absolute value of the two-frame difference with a threshold value (the absolute value of the two-frame difference that is to be determined to be a motion) for each detection region having a predetermined size, and the absolute value is larger than the threshold value. If it is small, it is determined to be moving, and if it is small, it is determined to be stationary. If it is determined to be stationary, the gain controller 1402 increases the edge sensitivity, and if it is determined to be moving, the gain controller 1402 is used.
The edge detection sensitivity is lowered. Therefore, the edge is strong in the stationary part and weak in the moving part.

In the present embodiment, since the accurate motion detection is not performed, the difference between two frames is used only for determining whether the motion is still or a motion close to the still motion.
Motion detection accuracy is not very important. Although the example of the two-frame difference has been described by taking the MUSE signal as an example, the same effect can be obtained with the one-frame difference when the sampling points match.

<Tenth Embodiment> FIG. 15 shows a tenth embodiment of the present invention. In FIG. 15, 11
Shows the same parts as in FIG. 1412 to 1415 indicate the same parts as in FIG. The one-frame delay circuit 101 of the interframe interpolation circuit 11, the ABS circuit 1412, the switch 1413, the spatial interpolation filter 1414, the threshold value processing circuit 1415, and the subtraction circuit 1511 constitute a simple motion detection circuit 151. ing. Subtraction circuit 1511
Is the MUSE signal and the MUSE signal delayed by 2 frames by the 1-frame delay circuit 101 of the interframe interpolation circuit 11.
The signal is subtracted from. Reference numeral 150 denotes a two-dimensional LPF, which performs inter-frame filter processing on the signal from the inter-frame interpolation circuit 11. Reference numeral 160 denotes an edge detecting means, which is the edge detecting means 14 shown in FIG. 14 except that the signal from the two-dimensional LPF 150 is processed.
It has the same function as 0.

Interframe interpolation circuit 11 performs interframe interpolation, and two-dimensional LPF 150 performs temporal processing. On the other hand, by utilizing the fact that the 1-frame delay circuit 101 of the inter-frame interpolating circuit 11 sequentially outputs the 1-frame delay output and the 2-frame delay output,
If the simple motion detection circuit 151 performs simple motion detection using the difference between frames, and if it is determined to be still, the gain controller 1602 increases the edge sensitivity, and if it is determined to be motion, the gain controller is used. 1602 reduces the edge detection sensitivity.

Therefore, in the eighth embodiment, the ratio of the edge detection sensitivities when the object is moving and when it is stationary is two-dimensional LP.
While the coefficient of F is fixed, in the present embodiment, the edge detection sensitivity can be controlled, so that finer control can be performed.

[0048]

As described above, according to the present invention,
Since it is configured as described above, it is possible to eliminate erroneous detection of motion due to insufficient bandwidth of the still edge and omission of motion detection due to high sensitivity of the motion edge, and it is possible to improve the accuracy of motion detection. The image quality can be further improved.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram for explaining conventional edge detection.

FIG. 3 is an explanatory diagram for explaining a principle of widening an edge band by interframe interpolation.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a block diagram showing a third embodiment of the present invention.

FIG. 6 is a block diagram showing a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a fifth embodiment of the present invention.

FIG. 8 is a block diagram showing an example of a recursive filter.

FIG. 9 is a block diagram showing an example of a non-recursive filter.

FIG. 10 is a block diagram showing a sixth embodiment of the present invention.

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

FIG. 12 is a block diagram showing an eighth embodiment of the present invention.

FIG. 13 is an explanatory diagram for explaining an example of the relationship between the calculation region and the coefficient of the two-dimensional LPF shown in FIG.

FIG. 14 is a block diagram showing a ninth embodiment of the present invention.

FIG. 15 is a block diagram showing a tenth embodiment of the present invention.

FIG. 16 is a block diagram for explaining the principle of moving area detection.

FIG. 17 is a diagram showing a sampling pattern of the MUSE method.

[Explanation of symbols]

11, 41, 51, 53, 61, 63 Interframe interpolating circuit 12, 54, 82, 122, 140, 160 Edge detecting means 52 1 field delay circuit 71, 81, 1102 Temporal filter 100, 400, 510, 530, 610,630,1
413 switches 101, 401, 511, 531, 611, 631 1
Frame delay circuit 1402, 1602 Gain controller

Front page continuation (72) Inventor Jun Fukuda 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Habunobu Mizutani 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Engineering Institute, Broadcasting Technology Research Institute (72) Inventor Yuichi Ninomiya 1-10-11 Kinuta, Setagaya-ku, Tokyo

Claims (12)

[Claims] 1. A unit of a predetermined number of two or more fields or frames formed by pixels of a sampling pattern different for each field or frame obtained by offset subsampling an image between fields or frames. An interpolated image generating means for interpolating using a plurality of consecutive odd or even fields of the band-compressed input image signal or a plurality of consecutive frames to repeat the unit, and the interpolated image. An image edge detection device comprising: an edge detection unit that detects an edge signal of an image generated by the generation unit. 2. A unit of a predetermined number of two or more fields or frames formed by pixels of a sampling pattern which is different for each field or frame obtained by offset subsampling an image between fields or frames. An interpolated image generating means for interpolating using a plurality of consecutive odd or even fields of the band-compressed input image signal or a plurality of consecutive frames to repeat the unit, and the interpolated image. A non-recursive temporal filter that adds two temporally consecutive interpolated images generated by the generation means at a predetermined ratio and outputs the result, and an edge detection that detects an edge signal of the image from the non-recursive temporal filter. An image edge detecting apparatus comprising: 3. A unit of a predetermined number of two or more fields or frames formed by pixels having a sampling pattern different for each field or frame obtained by offset subsampling an image between fields or frames, An interpolated image generating means for interpolating using a plurality of consecutive odd or even fields of the band-compressed input image signal or a plurality of consecutive frames to repeat the unit, and the interpolated image. A recursive temporal filter that adds the input signal from the generation means and the recursive input at a predetermined ratio and outputs the delayed signal, and delays the output by the time corresponding to the interpolated image to be the recursive input; Edge detection means for detecting an edge signal of an image from a cyclic temporal filter is provided. Image edge detecting apparatus according to claim. 4. A unit of a predetermined number of two or more fields or frames formed by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames, An edge detecting unit that detects the edge signal of the band-compressed input image signal that repeats the unit, and 2 that are temporally continuous detected by the edge detecting unit.
An image edge detecting apparatus comprising: a non-recursive temporal filter that adds edge signals corresponding to two image signals at a predetermined ratio and outputs the result. 5. A unit of a predetermined number of two or more fields or frames formed by pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames, An edge detecting unit that detects an edge signal of a band-compressed input image signal that repeats the unit, an edge signal detected by the edge detecting unit, and a recursive input are added at a predetermined ratio and output, and the output And a recursive input which is delayed by a time corresponding to the image signal and is used as the recursive input. 6. A unit of which is a predetermined number of two or more fields or frames, which are composed of pixels having different sampling patterns for each field or frame obtained by offset subsampling an image between fields or frames, An interpolated image generating means for interpolating using a plurality of consecutive odd or even fields of the band-compressed input image signal or a plurality of consecutive frames to repeat the unit, and the interpolated image. For the interpolated image generated by the generation means,
A two-dimensional or one-dimensional low-pass filter for calculating the value of the central pixel by multiplying each pixel included in a two-dimensional or one-dimensional fixed range centering on the pixel to be processed by a predetermined coefficient and adding An image edge detecting apparatus comprising: an edge detecting unit that detects an edge signal of an image from the low-pass filter. 7. A unit of a predetermined number of two or more fields or frames formed by pixels of a sampling pattern different for each field or frame obtained by offset subsampling an image between fields or frames. An edge detecting unit that detects an edge signal of a band-compressed input image that repeats the unit, an edge detecting unit that varies an output gain, and a motion detecting unit that detects a motion of the input image based on the input image signal. In addition, based on the result of motion detection, the motion detection means is configured to reduce the output gain of the edge detection means in a moving area and increase the output gain of the edge detection means in a stationary area. Image edge detector. 8. The image edge detecting apparatus according to claim 7, wherein the motion detecting means is arranged between two consecutive odd or even fields of the input image signal whose sampling patterns match or between two consecutive frames. Calculating means for calculating the absolute value of the difference signal, and spatially interpolating the absolute value of the difference signal calculated by the calculating means to generate a difference signal at a non-sampling point to obtain the absolute value of the difference signal. The spatial interpolation filter that outputs together with a value, and the difference signal that has been subjected to the interpolation from the spatial interpolation filter is compared with a predetermined threshold for each detection region having a predetermined size, When the inserted difference signal is smaller than the threshold value, a control signal for increasing the output gain of the edge detection means is output, and in other cases, the edge detection means of the edge detection means is output. An image edge detection device, comprising: a threshold processing circuit that outputs a control signal that reduces an output gain. 9. Claims 1 to 3 or claim 6.
In the image edge detecting device according to any one of items 1 to 3, the interpolated image generating means delays the input image signal of the edge detecting means by a delay time corresponding to the field or frame signal constituting the unit. A circuit, the input image signal, and the image signal from the delay circuit are alternately switched at the timing of the offset subsampling between the fields or the frames so that a plurality of consecutive fields or frames of the input image signal are generated. An image edge detecting apparatus comprising: a switching circuit that generates an interpolated image signal by using the interpolation circuit and outputs the generated interpolated image signal to the edge detecting means. 10. The image edge detecting device according to claim 1, wherein the interpolation image generating means is a delay corresponding to the field or frame signal forming the unit. One delay circuit for delaying the input image signal by time, the input image signal, and the image signal from the delay circuit are alternately switched at the timing of the offset sub-sampling between the fields or frames, A switching circuit for generating an interpolated image signal interpolated using a plurality of continuous fields or frames of an input image signal, wherein one switching output of the switching circuit is output to the delay circuit and the edge detection means. An image edge detection device including a switching circuit. 11. The image edge detecting device according to claim 1, wherein the interpolation image generating means is a delay corresponding to the field or frame signal forming the unit. First to n-th (n ≧ 1) delay circuits for delaying the input image signal by time,
To a delay circuit group in which n-th delay circuits are connected in series, and a first interpolated image generating means for interpolating the input image signal, the edge detecting means having the delay circuit and the switching circuit according to claim 9. 10. The first interpolated image generating means for outputting to, and the (n + 1) th interpolated image generating means for interpolating the image signals from the first to n-th delay circuits, the delay circuit according to claim 9. An image edge detecting apparatus comprising: a (n + 1) th interpolated image generating means having a switching circuit and outputting to the edge detecting means. 12. The image edge detecting device according to claim 1, wherein the interpolation image generating means is a delay corresponding to the field or frame signal forming the unit. First to m-th (m ≧ 1) delay circuits for delaying the input image signal by time
To a delay circuit group in which m-th delay circuits are connected in series, and a first interpolated image generating means for interpolating the input image signal, the edge detecting means having the delay circuit and the switching circuit according to claim 10. First interpolated image generating means for outputting to
The (m + 1) th interpolated image generating means for interpolating the image signal from the first to mth delay circuits, the delay circuit having the delay circuit and the switching circuit according to claim 10, and outputting to the edge detecting means. An image edge detection device comprising: (m + 1) interpolated image generation means.