JPH09284648A - Method and apparatus for detecting superimpose area - Google Patents

Abstract

(57) Abstract: In image processing including a moving image, if the processing method is not perfect, the image quality deteriorates. According to the method of the present invention, basically, an area having a small change in brightness level in the time direction is extracted from an image brightness signal in units of an area made up of a fixed number of pixels (2), and a fixed number of pixels are also extracted. (3) detects a still area of the image in units of areas consisting of (3), and detects the maximum brightness level in the area corresponding to both the detected still area and the extracted area with little change in brightness level in the time direction (4). Then
A threshold value is generated from the detected maximum brightness level (5),
Among the extracted areas with a small change in brightness level in the time direction, an area in which the brightness level exceeds the generated threshold value is detected (6) in units of the area including the certain number of pixels, and the detected area is superposed. It consists of each step of judging as an impose area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing of television images and the like, and more particularly to a method and apparatus for detecting a region superimposed on a moving image in a stationary state.

[0002]

2. Description of the Related Art Conventionally, in a television broadcasting station, in order to avoid the superimposition of its own station from overlapping with the existing superimpose, it is detected whether or not the television signal has a superimposition of characters or the like. In other words, for determining the presence or absence of superimpose, for example, Japanese Patent Application Laid-Open No. 5-328220, “Superimposing method” and Japanese Patent Application Laid-Open No. 6-178205, “Super character detecting method, apparatus and own-station super automatic cutting apparatus” are disclosed. , Etc. are known.

The former (Japanese Patent Laid-Open No. 5-328220) binarizes a luminance signal in an input television signal, further designates a specific existing superimpose survey range, and binarizes it within the designated range. The presence / absence of superimpose is determined from the edge information of the converted luminance signal. In addition, the latter (JP-A-6-17820)
No. 5) binarizes a signal of a specific scanning line or a part thereof and examines the pattern of the obtained data string over several frames to determine the presence or absence of superimposing. However, these are all for detecting the presence or absence of superimpose in the television signal.

[0004]

As described above, the conventional means for detecting the presence / absence of superimpose determines the superimpose at its own station when it is detected in the incoming television signal. It was intended to be used to discontinue.

On the other hand, not only television signals,
With the recent widespread image processing of image signals including moving images, when there are important meanings in the image, especially superimposed characters, etc. It is necessary to perform image processing by distinguishing it from the remaining area which is not. For this purpose,
It is not useful to simply detect the presence / absence of superimposition as in the conventional case, and it is necessary to detect the superimpose area.

An object of the present invention is to deteriorate the image quality when the processing method is not perfect in the image processing including a moving image. Especially, the area in which a character or the like is superimposed is an important image information area. Since it is fatal when deterioration occurs, only the superimpose area is detected, and image processing of the detected area is performed differently from other areas to minimize image deterioration in the superimpose area. To stay.

[0007]

In order to achieve the above object, in the method and apparatus for detecting a superimposing area of the present invention, basically, for each pixel in the screen, that pixel is a superimposing area. It is determined whether or not it is a part, and the superimpose area is detected as the total of the determination results. The detection of the superimpose area is performed for each pixel, and therefore threshold processing of the luminance signal level is used. However, the threshold is variable according to the screen, and at the same time, as a reverse of the motion area detection to further improve the detection accuracy. Use static area detection together. Here, the determination is most preferably performed for each pixel, but it is needless to say that the determination region may be expanded and a set of a plurality of pixels may be set as one unit if the detection accuracy is not so required.

That is, the method of detecting a superimposed area according to the present invention extracts an area having a small change in the brightness level in the time direction from the brightness signal of an image in the unit of an area consisting of a fixed number of pixels, and also the fixed number. Detecting a still region of the image in units of a region consisting of
The maximum brightness level in the detected still area and the area corresponding to both of the extracted areas with little change in brightness level in the time direction is detected, a threshold value is generated from the detected maximum brightness level, and the extracted time is detected. Direction, the area where the brightness level changes little is detected as an area where the brightness level exceeds the generated threshold value in units of the area consisting of the fixed number of pixels, and the detected area is determined as a superimpose area. It is characterized by comprising each step of

Further, in the method of detecting the superimposed area of the present invention, the area having a small change in the brightness level in the time direction is extracted from the brightness signal of the image in the unit of an area made up of a fixed number of pixels, and the fixed number is also the same. Detecting a still region of the image in units of a region consisting of pixels, and detecting the maximum brightness level in the region corresponding to both the detected still region and the extracted region with little change in brightness level in the time direction. A threshold value is generated from the detected maximum brightness level, and an area in which the brightness level exceeds the generated threshold value in the extracted area in which the brightness level changes little in the time direction is defined as an area including the predetermined number of pixels. As a unit for the detected area, and the brightness level is within the threshold value within a certain adjacent area in units of the area including the certain number of pixels. Whether or not to exceed, a majority process is performed, and, as a result of the majority process, a region in which the brightness level exceeds the generated threshold is determined as a superimpose region. is there.

The superimposing area detecting method of the present invention is characterized in that the area consisting of the predetermined number of pixels is an area of one pixel unit.

Further, in the superimposing area detecting method of the present invention, the constant adjoining area for performing the majority decision processing is a constant number of adjoining areas of 9 or more and 49 or less centered on the processing target area. It is characterized by.

Also, the superimposing area detecting apparatus of the present invention is a time-direction LPF for extracting an area having a small change in brightness level in the time direction from the brightness signal of an image in units of an area consisting of a fixed number of pixels. A still area detection unit that detects a still area of an image in units of the area composed of the fixed number of pixels, the detected still area, and the extracted area within the area corresponding to the area with little change in luminance level in the time direction. A maximum value detection circuit that detects a maximum brightness level, a threshold value generation circuit that generates a threshold value from the detected maximum brightness level, and a threshold value that the brightness level has generated in the extracted area with little change in brightness level in the time direction. A threshold value processing circuit for detecting and outputting the exceeding area in units of the area composed of the fixed number of pixels. A.

Further, in the superimposing area detecting apparatus of the present invention, the brightness level is set in a certain adjacent area in units of the area made up of the certain number of pixels with respect to the area detected by the threshold processing circuit. The present invention is characterized in that a majority voting circuit that performs majority voting processing to output whether or not the generated threshold is exceeded is cascade-connected to the threshold processing circuit.

Further, the superimposing area detecting apparatus of the present invention is characterized in that the area composed of the predetermined number of pixels is an area of one pixel unit.

Further, in the apparatus for detecting a superimposed area of the present invention, the still area detecting section calculates an interframe and / or field difference calculation circuit for calculating an absolute value of an interframe and field difference of the image. An inter-frame or inter-field difference calculation circuit output, or a bit number reduction circuit that reduces the number of bits of the combined result of both calculation circuit outputs, and a recursive filter that uses the output signal of the bit number reduction circuit as an input signal. Compared with the filter output of 1 field or 1 frame before, if the filter output of 1 field or 1 frame before is larger, output the value obtained by subtracting a certain value from the filter output of 1 field or 1 frame before However, if the filter output of one field or one frame before is smaller or equal, A recursive filter that selects and outputs a filter input signal, a binarization circuit that inverts the sign of the recursive filter output based on a preset threshold value, and outputs the binarized circuit, and the binarization circuit output. A region in which a fixed number of pixels are used as a unit, addition is performed within a fixed adjacent region, and the addition output exceeds a preset threshold value and the LPF output exceeds a preset threshold value. It is characterized by including a majority decision / threshold processing circuit for outputting a detection signal.

Further, in the superimposing area detecting device of the present invention, the constant adjoining area for performing the majority decision processing is a constant number of adjoining areas of 9 or more and 49 or less centered on the processing target area. It is characterized by.

Further, in the superimposing area detecting apparatus of the present invention, the constant adjacent areas to which the binarization circuit outputs are added are adjacent to each other by a constant number of 9 or more and 49 or less centering on the processing target area. It is characterized by being a region.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a superimposing area detecting apparatus according to the present invention. Refer to Figure 1,
Reference numeral 1 is a matrix circuit, 2 is a time direction low pass filter (LPF), 3 is a stationary area detection unit, 4 is a maximum value detection circuit, 5 is a threshold value generation circuit, 6 is a threshold value processing circuit, 7 is a delay circuit, and 8 Is a majority circuit.

The stationary area detection unit 3 in FIG. 1 includes an interframe difference calculation circuit 9, an interfield difference calculation circuit 10, a synthesis circuit 11, a 16-value conversion circuit 12, a recursive filter 13, and a binary conversion circuit 14, respectively. , A majority / threshold processing circuit 15 and a delay circuit 16.

Next, the operation will be described. First, the matrix circuit 1 creates a luminance signal from the input RGB signal and supplies it to the LPF 2 and the stationary area detection unit 3 in the time direction. With the LPF 2 in the time direction, an image signal in which only the signal with a small change in the brightness level in the time direction is emphasized can be obtained. On the other hand, the stationary area detection unit 3 detects a stationary area in the target field. LPF 2 and stationary area detection unit 3 in the time direction
The maximum value detection circuit 4 to which the respective outputs are supplied detects the maximum brightness level among the signals in the static area and the area in which the brightness level changes little in the time direction. On the other hand, the threshold value generation circuit 5 generates a threshold value corresponding to the maximum luminance level, and the threshold value processing circuit 6 performs threshold value processing of a signal (LPF output in the time direction) with little change in the luminance level in the time direction. The delay circuit 7 is necessary for the phase matching between the threshold value in the threshold value processing circuit 6 and the signal having a small change in the brightness level to be thresholded.

Here, the threshold processing means, for example, a circuit operation such that an output is generated only when the input signal exceeds the threshold. Here, as a result of performing the threshold processing on the output signal of the delay circuit 7, detection is performed. The target field is divided into two areas, an area that exceeds the threshold and an area that does not exceed the threshold, and further, after passing through a majority circuit 8 for avoiding false detection like an isolated point, the threshold is finally set without including the isolated point. The exceeded area is determined to be the superimposed area in the field. Note that the majority circuit 8 is not necessary if erroneous detection like an isolated point is allowed.

In the following, each constituent block of the superimposing area detecting apparatus of the present invention shown in FIG. 1 will be described in detail. First, when the input signal is a luminance signal and a color difference signal, the matrix circuit 1 passes only the luminance signal as it is and the following circuits (LPF 2 in the time direction, inter-frame difference calculation circuit 9 and inter-field difference calculation circuit 1
0) input signal. When the input signal is R, G, B signals as shown in the figure, a luminance signal is created by a luminance signal equation Y = 0.701G + 0.087B + 0.212R (1) such as SMPTE240M in the SMPTE standard. To do.

Next, the LPF 2 in the time direction is a kind of a signal that makes a signal in a region that does not change much in the time direction have a large brightness level as compared with other regions (regions in which the change in the time direction is large). LPF. The LPF is realized by the circuits shown in FIGS. 2 and 3, respectively. FIG. 2 shows a case where the LPF is configured in a cyclic type.
In the figure, fb represents the feedback amount with a preset arbitrary coefficient of 0 to 1. Reference numeral 21 denotes a multiplier, which multiplies the luminance signal Y ₂ (t) by 1-fb. 24 is also a multiplier, which multiplies the signal fed back (the signal one field before) by fb. 22 is an adder, which is a multiplier 2
The output signals of 1 and 24 are added. The added signal is output as the output signal of the LPF and is also fed back to the input side by the field delay circuit 23 with a delay of one field. Compared to an area (such as a moving area) where the brightness level changes between fields by passing through such a filter, a still area with a high brightness level keeps the brightness level as it is and a higher brightness level than other areas. The probability of becoming becomes large. The output signal Y ₂ ′ (t) of this LPF is represented by Y ₂ ′ (t) = fb × Y ₂ ′ (t−1) + (1−fb) × Y ₂ (t) (2).

FIG. 3 shows a case where the LPF is constructed as a non-recursive type. Reference numerals 31, 32, 33 and 34 are field delay circuits, and in this case, F3 shown in the figure is a field to be processed. In this example, the luminance level of each signal of F1, F2, F4, and F5 is F by using two fields F1, F2, F4, and F5 around the processing target field F3.
The F3 signal is output as it is through the switch SW50 only when it is between 0.9 times and 1.1 times the brightness level of No. 3, and in other cases, the brightness level of the F3 signal is replaced with 0 and output. I am trying. Further, the circuits denoted by 35 and 36 are circuits for multiplying the brightness level of each pixel of the F3 signal by 0.9 times and 1.1 times, respectively. Of course, this may be another multiple. The circuit from 37 to 44 is F
A comparison circuit for comparing each signal of F1, F2, F4, and F5 with a F3 signal multiplied by a constant, and F1 is generated by the circuits 45 to 49 to which the outputs of these comparison circuits are supplied.
The switch SW50 outputs the F3 signal only when all the brightness levels of the F2, F4, and F5 signals satisfy the condition (that is, between 0.9 times and 1.1 times the brightness level of the F3 signal). I am trying to do it. L shown in FIG.
The operation of the PF is expressed by the following equation. (0.9 ・ F3 <F1 <1.1 ・ F3) AND (0.9 ・ F3 <F2 <1.1 ・ F3) AND (0.9 ・ F3 <F4 <1.1 ・ F3) AND (0.9 ・ F3 <F5 <1.1 ・ F3) → the output signal Y _'3 = F3 other when → output signal Y' ₃ = 0 ₍₃₎

In the following, the stationary area detecting section 3 shown by being surrounded by a broken line in FIG. 1 will be described in detail. First, the inter-frame difference calculation circuit 9 is a circuit that calculates the absolute value of the inter-frame difference for each pixel.
0 is a circuit for calculating the absolute value of the inter-field difference for each pixel. The synthesizing circuit 11 is a circuit that calculates the average value of the absolute values of the differences calculated by the circuits 9 and 10. Now, the LP shown in FIG. 3 as the LPF 2 in the time direction
The absolute value of the inter-frame difference when F is used is fr_d1 = | F1-F3 | fr_d2 = | F5-F3 | (4) The absolute value of the inter-field difference is fi_d1 = | F2-F3 | fi_d2 = | F4-F3 | (5) (In this case, unlike the circuit connection shown in Fig. 1,
The signals from F1 to F5 of the LPF2 in the time direction are supplied to the calculation circuits 9 and 10, and as a result, that is, the output of the synthesis circuit 11 is fd = (fr_d1 + fr_d2 + fi_d1 + fi_d2) / 4 (6).

On the other hand, when the cyclic LPF shown in FIG. 2 is used as the LPF in the time direction, the inter-frame difference and the inter-field difference are irrelevant to the LPF 2 in the time direction and are connected by the matrix circuit 1 shown in FIG. The inter-frame difference and the inter-field difference of the output signal of are calculated. Therefore, the interframe difference calculation circuit 9 includes a frame delay circuit, and the interfield difference calculation circuit 10 includes a field delay circuit. In the above, the inter-frame and inter-field difference calculation circuits 9 and 10 may be provided with only one of them.

Next, the hexadecimalization circuit 12 includes the synthesizing circuit 11
Output, that is, the combined value of the differences between the frames and between the fields is a certain fixed value, in this example, when the input signal Y ₄ is at level 15 or higher, it is replaced with 15 (see FIG. 4). Is a circuit that performs. FIG. 4 shows the input / output characteristics of this circuit in the case of changing 8 bits (level 255) to 4 bits (level 15) (reducing the number of bits). The value of 16 is not limited to 16 and may be any other value, but this value is not limited to the recursive filter 13.
The larger this value, the slower the magnitude of the motion detection signal in the recursive filter in the time direction.

The recursive filter 13 is a circuit for preventing the signal supplied from the hexadecimalization circuit 12 in the preceding stage from suddenly becoming small. Chicasive filter 1
FIG. 5 shows an example of the configuration of No. 3. 5, 53 is a field delay circuit, one field before the signal Y _'5 (t
−1) level and the level of the input signal Y ₅ (t) are compared by the comparator 52.
If the signal level one field before the input signal level is higher than the input signal level, the value of the output signal Y ′ ₅ (t) obtained via the switch SW51 is obtained from the signal level one field before by −1 shown in the figure. A value obtained by subtracting 1 is selected by the subtraction circuit 54, and conversely, when the value is equal or smaller, the value of the input signal level is selected. That is, in this circuit, when the combined value of the differences between the frames and between the fields (the output of the combining circuit 11) becomes abruptly small, the level decrease is suppressed by one, that is, it does not become abruptly small. Further, when the combined value of the differences suddenly increases, the control is performed so that the response will be returned as it is. As a result, the possibility that the moving area is mistaken for the stationary area (missing detection of the moving area) can be suppressed.

The binarization circuit 14 is used for the recursive filter 1
It is a circuit that receives three output signals (16 values) and binarizes them (0 or 1). In the present example, as shown in FIG. 6, when the level of the input signal Y ₆ (output of the recursive filter 13) is 5 or less and above, the levels of the output signal Y ′ ₆ are 0 and 1 respectively. The binarization is performed so that Here, the level 5 that is the reference for binarization is an arbitrary value set in advance,
The number is not limited to 5.

The majority / threshold processing circuit 15 that finally forms the output signal (stationary area signal) of the stationary area detection unit 3 is
For example, it is configured as shown in FIG. In this example, it is assumed that addition is performed for all values of 9 pixels (3 × 3 pixels) centered on the pixel of interest. This addition range is usually 3
It may be wider than × 3, but practically 7 × 7 is sufficient.

In FIG. 7, the 3 × 3 pixel addition circuit 71 adds the values of 9 × 3 × 3 pixels centering on the pixel of interest, and the value (add_y) is preset in the next comparison circuit 72. The threshold value (Th ₁ ) (5 in this example) is compared. On the other hand, for example, LPF2 in the time direction (see FIG. 1)
F3 signal when using the one shown in Fig. 3 (a signal that does not pass through the LPF in the time direction in other cases)
Level and any preset threshold (T
h ₂ ) (220 in this example) is compared by the comparison circuit 73. Then, the selection of the value of the output (Y) is performed by the OR circuit 74: add_y <5 OR F3 <220 → Y ′ ₇ = 16 (that is, moving image area) (7) If not → Y ′ ₇ = 200 (that is, still) Area) (8). The delay circuit 16 for supplying the F3 signal is input to the majority / threshold processing circuit 15 (in this example, the Y ₇ signal and the F3 signal are input).
It is a delay circuit for adjusting the time of signals). Through the above signal processing, a stationary area in units of an area of 9 pixels is detected from within the target field.

The signal representative of the detected still region (Y region to be _'7 (t)) and the maximum value is supplied to the detection circuit 4 of each field Y shown in FIG. 1' ₇ = 200 (still region) The maximum value of the output signal of the LPF 2 in the time direction is obtained by limiting only to the inside. Now, assuming that the maximum value is Max, the threshold value generation circuit 5 generates a threshold value proportional to Max. Here, for example, the threshold value is set to a constant multiple such as 0.8 times Max. Then, the threshold processing circuit 6 performs threshold processing on the LPF output signal in the time direction using the threshold, and the LPF output signal in the time direction> 0.8 × Max → threshold processing circuit output = 1 (9) LPF output signal in the time direction ≦ 0.8 × Max → threshold processing circuit output = 0 (10).

The majority circuit 8 to which the output (1,0 signal) of the threshold processing circuit is supplied is for removing an isolated point, and FIG. 8 shows an example of its configuration. In this example, the 3 × 3 pixel adder circuit 81 adds the values of all 9 pixels of 3 × 3 (generally, 7 × 7 at the maximum is sufficient) centering on the pixel of interest. The comparison circuit 82 compares a preset threshold value (Th: 3) (3 in this example) with the addition result. If the threshold value is exceeded, the output is set to 1 and otherwise the output is set to 0. That is, add_cont <3 → cont ′ = 0 (11) add_cont ≧ 3 → cont ′ = 1 (12). The area (cont '= 1) in which the output obtained from the majority decision circuit 8 is 1 as described above is determined to be the superimpose area.

[0034]

EFFECTS OF THE INVENTION As general features of a stationary superimpose area such as a character, The brightness signal level is high. 2. The correlation in the time direction is large. 3. There are the following characteristic correlations in space. -In the edge part, the correlation of the luminance level is large in the edge direction and the tangential direction.・ Except for the edges, the correlation is large in all directions. 4. It often appears in a specific position on the screen. The present invention is not limited to these. And 2. Since it is a method and apparatus for detecting a superimposing area using the characteristics of (1), the central part thereof can be realized with a relatively simple configuration of stationary area detection and level threshold processing, and can be easily implemented as a device. As a detection error, there is a possibility that erroneous detection may occur in signals other than the superimpose region where the brightness level is high, but in many image processing, the region that is erroneously detected here is detected as the superimpose region. In many cases, the image quality is less likely to deteriorate even if processed.

Further, among the features of the superimpose area, the position at which the superimpose area appears can be easily realized by a method in which the operator designates it at a specific position on the screen, and the effect is great. Can be expected. Therefore, this method can be used in combination with the present invention. According to the present invention, it is possible to relatively easily detect a superimpose area without causing erroneous detection that greatly affects many image processes.

Generally, in the image processing including a moving image, if the processing method is not perfect, the image quality is deteriorated. Especially, the superimpose portion is important image information, and if the image quality is deteriorated in that portion, it is troublesome. Therefore, according to the present invention, by detecting only the superimpose area and subjecting the area to a separate process, the image quality deterioration of the superimpose area such as characters can be minimized.

For example, in a television system conversion or the like, a character or the like superimposed on an image panning the camera is corrected (pulled) by a background vector due to panning, resulting in a large deterioration in image quality. As a result of attempting improvement by using the present invention in a simulation experiment for reducing image quality deterioration in the superimpose region, good results were obtained.

In the superimposing area detecting apparatus of the present invention, the stationary area detecting section in the block diagram of FIG. 1 is the inside of the moving area detecting section. When the area detection unit is provided, it can be used also, and the device of the present invention can be realized more easily and economically.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a device for detecting a superimposed region of the present invention.

FIG. 2 shows a circuit diagram when the LPF in the time direction shown in FIG. 1 is configured in a cyclic type.

FIG. 3 is a circuit diagram when the LPF in the time direction shown in FIG. 1 is configured as a non-recursive type.

FIG. 4 shows input / output characteristics of the 16-valued circuit shown in FIG.

5 shows a configuration of an example of the recursive filter shown in FIG.

FIG. 6 shows an operation example of the binarization circuit shown in FIG.

FIG. 7 shows a configuration example of a majority / threshold processing circuit shown in FIG.

8 shows an example of the configuration of the majority decision circuit shown in FIG.

[Explanation of symbols]

1 matrix circuit 2 low-pass filter (LPF) in the time direction 3 stationary area detection unit 4 maximum value detection circuit 5 threshold value generation circuit 6 threshold value processing circuit 7, 16 delay circuit 8 majority circuit 9 frame difference calculation circuit 10 field difference Calculation circuit 11 Combining circuit 12 16-valued circuit 13 Recursive filter 14 Binarized circuit 15 Majority / threshold processing circuit 21, 24 Multiplier 22 Adder 23 Field delay circuit 31, 32, 33, 34 Field delay circuit 35 0.9 Doubler circuit 36 1.1 Doubler circuit 37, 38, 39, 40, 41, 42, 43, 44 Comparison circuit 45, 46, 47, 48, 49 OR circuit 50, 51 Switch SW 52 Comparison circuit 53 Field delay circuit 54- 1 subtraction circuit 71 3 × 3 pixel addition circuit 72, 73 comparison circuit 74 OR circuit 81 3 × Pixel addition circuit 82 comparison circuit

Claims (10)

[Claims] 1. An area in which a change in brightness level in the time direction is small is extracted from a brightness signal of an image by using an area including a certain number of pixels as a unit, and an area including the same number of pixels is also used as a unit of the image. A still area is detected, a maximum brightness level in an area corresponding to both the detected still area and the extracted area with little change in brightness level in the time direction is detected, and a threshold is generated from the detected maximum brightness level. Then, in the extracted area with little change in the brightness level in the time direction, an area in which the brightness level exceeds the generated threshold value,
A method for detecting a superimpose area, comprising steps of detecting the area composed of the predetermined number of pixels as a unit, and determining the detected area as a superimpose area. 2. An area in which a change in the brightness level in the time direction is small is extracted from an image brightness signal in units of an area made up of a fixed number of pixels, and an area made up of the fixed number of pixels is also set as a unit. A still area is detected, a maximum brightness level in an area corresponding to both the detected still area and the extracted area with little change in brightness level in the time direction is detected, and a threshold is generated from the detected maximum brightness level. Then, in the extracted area with little change in the brightness level in the time direction, an area in which the brightness level exceeds the generated threshold value,
Whether or not the luminance level exceeds the threshold value within a certain adjacent region, with respect to the detected region, by detecting the region including the certain number of pixels as a unit A majority decision process is performed, and the result of the majority decision process includes the steps of determining an area in which the brightness level exceeds the generated threshold value as a superimpose area. Detection method. 3. The method for detecting a superimpose area according to claim 1, wherein the area composed of the fixed number of pixels is an area in units of one pixel. . 4. The method for detecting a superimposing area according to claim 2, wherein the predetermined adjacent area for performing the majority process is a constant number of adjacent areas of 9 or more and 49 or less centered on the processing target area. A method for detecting a superimpose area, characterized by: 5. An LPF in the time direction, which extracts from the brightness signal of the image a region having a small change in the brightness level in the time direction in units of a region consisting of a fixed number of pixels, and a still region of the image from the fixed number of pixels. A unit for detecting a maximum brightness level in a region corresponding to any of the detected static region and the extracted region with a small change in brightness level in the time direction, A threshold value generation circuit that generates a threshold value from the detected maximum brightness level, and an area in which the brightness level exceeds the generated threshold value in the extracted area with little change in brightness level in the time direction is composed of the certain number of pixels. An apparatus for detecting a superimposed area, comprising a threshold processing circuit for detecting and outputting the area as a unit. 6. The superimposing area detection device according to claim 5, wherein, with respect to the area detected by the threshold value processing circuit, the area composed of the certain number of pixels is used as a unit within a certain adjacent area. A detection apparatus for a superimpose region, wherein a majority decision circuit that performs a majority decision process as to whether or not a brightness level exceeds the generated threshold value and outputs the result is cascade-connected to the threshold value processing circuit. 7. The superimposing area detecting device according to claim 5, wherein the area composed of the predetermined number of pixels is an area in units of one pixel. . 8. The superimposing area detecting apparatus according to claim 5, wherein the stationary area detecting unit calculates an absolute value of a difference between frames of the image and between fields and / or between fields. A difference calculation circuit, a bit number reduction circuit that reduces the number of bits of the inter-frame or inter-field difference calculation circuit output, or the combined result of both calculation circuit outputs, and a recursive filter that uses the bit number reduction circuit output as an input signal. , The filter input is compared with the filter output of one field or one frame before, and if the filter output of one field or one frame before is larger, a constant value is obtained from the filter output of one field or one frame before. Output the subtracted value and check whether the filter output of one field or one frame before is smaller. If not, a recursive filter that selects and outputs the filter input signal, a binarization circuit that inverts the sign of the recursive filter output based on a preset threshold, and outputs the binarized signal; and The binarization circuit output is added within a certain adjacent region in units of the region composed of the certain number of pixels, the addition output exceeds a preset threshold value, and the LPF output is a preset threshold value. A superimposing region detection apparatus comprising a majority / threshold processing circuit that outputs a still region detection signal for a region exceeding the above. 9. The superimposing area detection device according to claim 6, wherein the constant adjacent area for performing the majority decision processing is a constant number of adjacent areas of 9 or more and 49 or less centered on the processing target area. A device for detecting a superimpose area, characterized by: 10. The superimposing area detection device according to claim 8, wherein the constant adjacent area to which the binarization circuit outputs are added is a constant value of 9 or more and 49 or less centered on the processing target area. 1. A device for detecting a superimpose area, characterized by being areas adjacent to each other.