JP2624522B2 - Motion detection circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion detection circuit for detecting a degree of motion between image signals representing an image.

2. Description of the Related Art In general, movement of an image in a screen such as a TV screen is roughly classified into movement of an object in the image and uniform movement of the entire image due to parallel movement of a camera. For example, when transmitting such an image, band compression of the image is performed for the purpose of efficiently using the transmission path.

A local moving part of the object in the image is processed as a moving area, and in one direction of movement of the entire image, a motion vector is detected and processed as a still area. A method of transmitting data after compression is well known, and many motion detection circuits have been devised and used.

However, depending on the application of the imaging apparatus, there is a case where it is sufficient to reliably detect the magnitude of the motion amount without distinguishing such a local motion of the image from a one-way motion of the entire image. Such applications include security devices and
In addition to the adaptive Y / C separation device and the progressive scan conversion device shown in Japanese Patent No. 106288, as a still image output of an electronic endoscope device used in a medical device, a subject image in a state as stationary as possible is provided with high resolution. (That is, a frame freeze with little color shift and image blur is performed in the frame sequential imaging method, and a frame freeze with little field flicker is performed in the simultaneous imaging method).

Note that the above-described plane sequential imaging method is to sequentially image a subject illuminated with illumination light of different wavelength regions sequentially, and then synthesizes and forms a color image. The simultaneous method is a color filter under white illumination. In this case, color imaging (image) is performed in one imaging by an imaging unit using the image processing.

The above-described motion detecting circuit is disclosed in
As disclosed in Japanese Patent Publication No. 106288, a device has been devised which detects the degree of movement from an inter-frame difference signal of a luminance signal and a cumulative value of absolute values of neighboring pixel difference signals of the luminance signal.

[Problems to be Solved by the Invention] However, in the above-described conventional example, the cost is relatively high and the circuit scale is large when configuring the conventional example, and the magnitude of the movement cannot always be accurately determined.

The present invention has been made in view of such circumstances, and realizes a reduced circuit scale, low cost, and a high detection rate by a method that does not use an inter-frame difference signal as a motion detection method. It is another object of the present invention to provide a motion detection circuit which does not cause erroneous detection at an edge portion of an image which is likely to occur when an inter-frame difference signal is used, and has a high detection rate even in an image having low autocorrelation.

[Means for Solving the Problem and Action] The motion detection circuit according to the present invention is a motion detection circuit that detects the motion of a subject image based on an image signal that is continuously captured at a predetermined frame / field cycle by an imaging unit. For a first image signal in a predetermined period of the image signal continuously captured, a difference signal of adjacent pixels is obtained at intervals of a predetermined sampling period, and the difference signal is set to n as an integer of 2 or more. By converting into n-values, the first
A first difference n-value converting means for outputting a signal representing the characteristic of the image signal, and a second image picked up by the image pickup means having a predetermined frame / field cycle different from the first image signal.
For the image signal of the above, at intervals of the predetermined sample period,
A difference signal between adjacent pixels is obtained, and the difference signal is calculated as n = 2.
A second difference n-value conversion unit that outputs a signal representing the feature of the second image signal by converting the value into an n-value as the above integer, and output by the first and second difference n-value conversion units Comparing means for comparing the coincidence and non-coincidence of each signal and outputting a signal indicating a period of coincidence and non-coincidence between the respective signals; and quantifying the motion amount of the subject image based on the signal output by the comparing means. And quantification means.

It is to be noted that the gist of the present invention is to use an inter-frame difference signal without using an inter-frame difference signal, convert the n-valued signal level gradient by a difference signal of an adjacent pixel into an n-value at an interval of a predetermined sample period. The comparison is performed between images to be subjected to motion detection.

According to the comparison output of the comparison means, the match, mismatch,
Alternatively, the amount of motion can be quantified and detected based on the similarity. The image signals to be compared are R,
The present invention is applicable to a single or arbitrary combination of color signals such as G and B, a luminance signal, and a color difference signal.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to the drawings.

1 to 7 relate to a first embodiment of the present invention, FIG. 1 is a basic configuration diagram of the first embodiment, FIG. 2 is a configuration diagram of an encoding unit, and FIG. FIG. 4 is a block diagram of the comparing means, FIG. 5 is an operation explanatory diagram of the comparing means,
FIG. 6 is a configuration diagram of the quantification means, and FIG. 7 is an explanatory diagram showing detection characteristics of the first embodiment.

As shown in FIG. 1, the motion detection circuit 1 of the first embodiment
Input terminals 2a, to which the synchronized R, G, B signals are respectively applied
Encoding means 3a, 3b, 3c provided with 2b, 2c respectively convert the pixel difference signal of the input signal into an n-value, encode the n-value into an n-value, and output. Each of the n-valued output signals is conceptually considered to be a result of approximating the fine powder output of the input signal with n types of direction vectors. Therefore, if each input signal R, G, B has a correlation, the direction vectors of each signal are the same or similar,
Without correlation, they do not match or dissimilar. Then, each signal is compared with the coded output signal by the comparison means 4 and further quantified by the quantification means 5 so that the magnitude of the motion amount can be detected. Output as signal 7. Here, the input signals are R, G, and B for the sake of explanation, but the combination of the input signals is not limited to this, and the same applies to the following description.

FIG. 2 shows a specific block configuration of the encoding means 3a or 3b or 3c (hereinafter, represented by 3i, where i = a or b or c), and is used when detecting motion in the horizontal or vertical direction. Applied.

Image signals such as R, G, and B as input signals are input to a low-pass filter (abbreviated as LPF) 12 via an input terminal 11.
The LPF 12 performs a predetermined band limitation, and one of them is a delay unit 13.
Is input to the difference / n-value conversion means 14 via the other. The delay means 13 delays by one sample period. Two input signals of the delayed image signal A and the undelayed image signal B are input to the difference / n-value conversion means 14, and these two signals are compared. According to the result, the data is converted into an n value in a decoding format or an encoding format and output. The output signal is input to the comparison means 4 via the output terminal 15.

 FIG. 3 shows the configuration of the difference / n-value conversion means 14.

The two input signals A and B are compared by the comparator 16, and the signals of A> B, A = B and A <B are output from the three output terminals in a decode format.

 Next, a specific configuration of the comparing means 4 is shown in FIG.

In this case, the input signal is a differential / ternary signal in the decoding format shown in FIG. That is, A> B, A = B, A in FIG.
<B is ΔR> O (or ΔG> O or ΔB>, respectively)
O), ΔR = O (or ΔG = O or ΔB = O), ΔR <
O (or ΔG <O or ΔB <O), ΔR, ΔG, Δ
B represents each signal.

ΔR> O, ΔG> O are exclusive OR (EX-OR) circuits
21, ΔR = O, ΔG = O is an EX-OR circuit 22, ΔR <O, ΔG <
O is an EX-OR circuit 23, ΔG> O, ΔB> O is an EX-OR circuit 24,
ΔG = O, ΔB = O are EX-OR circuits 25, ΔG <O, ΔB <O are
Exclusive OR, respectively, through the EX-OR circuits 26,
That is, coincidence and non-coincidence are detected. These are ORed through three-input OR circuits (OR circuits) 27 and 28, respectively, and then ORed through a two-input OR circuit 29 to be ORed. The correlation between the signals is obtained and output from the output terminal 30 to the quantification means 5. Here, any one of the EX-OR circuits 21, 22, and 23 and any one of the EX-OR circuits 24, 25, and 26 are not necessarily required. (Note that in FIG. 4, the difference / n-value conversion circuits 14 formed using the comparator 16 in FIG. 3 are indicated by 14a, 14b, and 14c, respectively.) FIG. 5 shows a visual model.

As shown in FIG. 5, when the level of the image signals R, G, and B on the vertical axis changes with time with respect to the time on the horizontal axis, that is, when a motion occurs, the difference / ternary signal at a predetermined sample interval (Represented by ±, 0,-for convenience) are ΔR, ΔG, Δ
As shown on the right side of B. Therefore, the OR circuit of FIG.
The outputs of 27, 28 and 29 are FL1, FL2 and FLAG of FIG. 5, respectively.
It becomes as shown by. Here, as is clear from the comparison between FL1 and FL2, it is clear that the higher the amount of motion, the longer the high-level output period of the OR circuits 27 and 28.

FIG. 6 shows an example of the configuration of the quantification unit 5, and the counter 31 constitutes the quantification unit 5. The output of the comparing means 4 is a clock enable terminal (CK
EN), and by counting a predetermined clock CK from a clock generator (not shown), the output terminal 6 can obtain signal data quantified according to the amount of movement. still,
A pulse corresponding to the period of the image signal to be correlated is applied to the clear terminal CLR. For example, one field /
If a vertical synchronization pulse is applied for each frame, the amount of motion between one field / frame is quantified.

According to the first embodiment, it is possible to realize a motion detection circuit which is hardly affected by the contents (APL, color tone, frequency components, etc.) of an image. For example, the relationship between the amount of motion and the detected value for the image Ga whose edge is clearly visible and the image Gb that is entirely flat is as shown in FIG. 7, and both the images Ga and Gb are accompanied by an increase in the amount of motion. It can be confirmed that the detected value shows a tendency of uniformly increasing. According to the first embodiment, the magnitude of the motion amount of the image signal can be quantified with high accuracy, and the present invention can be applied to various signal processing devices using motion information.

FIG. 8 shows a motion detection circuit 41 according to a second embodiment of the present invention.

This embodiment shows a case where the present invention is applied to a simultaneous imaging method.

Image signals captured at different times are input to a frame (or field) memory 43 via an input terminal 42 and to an encoding means 44. The image signal delayed by one frame (or field) period by the frame (or field) memory 43 is input to the encoding means 45. These encoding means 44 and 45 convert each input signal into n-valued difference signals of sample values at predetermined sampling periods, encode and output the signals. The coded signal output is input to the comparing means 46, and after being compared, is input to the quantifying means 47, quantified, and the output terminal 48 outputs a quantified signal according to the amount of motion. .

The encoding means 44 and 45 can be configured as shown in FIG. Also, the comparison means 46 and 47 of the first embodiment can be applied.

Further, the encoding means 4, 44, 45 can be constituted by using the encoding means 50 in the third embodiment shown in FIG.

That is, the encoding means 4 shown in FIG. 2 detects a motion in either the horizontal direction or the vertical direction, whereas FIG. 9 shows a specific configuration for detecting motion in the horizontal direction and the vertical direction. Show.

The image signal is input to the LPF 52 via the input terminal 51. The LPF 52 performs a predetermined band limitation and inputs the result to a line memory 53, a delay unit 54, and a difference / n-value conversion unit 55. The signal delayed by a predetermined horizontal line period by the line memory 53 is delayed by a delay unit 56, subjected to delay correction with the output of the delay unit 54, and then input to a difference / m-value conversion unit 57.

The signal delayed by one sample period by the delay unit 54 is input to the difference / n-value conversion unit 55 and the difference / m-value conversion unit 57. The difference / n-value conversion means 55 compares the two signals adjacent in the horizontal direction at the interval of the one sample period, and based on the result, converts the two signals into n values in a decode format or an encode format to obtain n × m
Output to the encoding means 58. At the same time, the difference / m-value converting means 57 compares the two signals which are close to each other in the vertical direction at the predetermined horizontal line interval, and, based on the result, converts the two signals into m-values in a decoding format or an encoding format to obtain an n × m coding device Output to

The outputs of the difference / n-value conversion means 55 and the difference / m-value conversion means 57 conceptually approximate the partial differential outputs of the input signal in the horizontal and vertical directions with vectors in n and m directions, respectively. It is considered something.

Therefore, by combining these two outputs, it can be considered that the gradient at each sample point of the input signal is approximated by n × m kinds of direction vectors. This combination is performed by the n × m encoding means 58 and output to the comparing means 46 (or 4 in FIG. 1) via the output terminal 59.

FIG. 10 shows a motion detection circuit 61 according to a fourth embodiment of the present invention.

This motion detection circuit 61 can be applied to a frame sequential imaging method as in the first embodiment.

This motion detection circuit 61 is the same as that of the third embodiment shown in FIG.
This is an example of a case where the partial differential outputs in the horizontal direction and the vertical direction are independently compared and quantified without calculating the gradient by the xm encoding means 58, and the motion amount is detected by the added output.

The encoding means 60a, 60b, and 60c have the same configuration as the portion 60 shown by a dashed line in FIG.

The synchronized R, G, and B signals are applied to the input terminals 62a, 62b, and 26c, respectively, and the encoding means 60a, 60b, and 60c respectively provide a horizontal difference / n-valued output and a vertical difference.・
An m-valued output is obtained. The difference / n-valued output in the horizontal direction is compared by the comparing means 63, and the comparison output is quantified by the quantifying means 64 to which the output is inputted, and inputted to the adder 65. Also,
At the same time, the difference / m-valued output in the vertical direction is
Is input to the quantification means 67, and is input to the quantified adder 65. The adder 65 adds the two signals and outputs a signal quantified in accordance with the amount of movement from an output terminal 68.

By the way, the portion constituted by the quantification means 64 and 67 and the adder 65 may be subjected to weighting processing, that is, addition by weighting.

FIG. 11 and FIG. 12 show another configuration example of the difference / n (or m) value conversion means 14 of FIG. This means can be used as reference numerals 55 and 57 in FIG.

Fig. 11 shows a comparator that uses a ROM or PLD to make a difference and quinary.
71, and five values of A >> B, A> B, A = B, A <B, A << B are output in a decoding format.

In this configuration example, A >> B and A >> B, and A <<
The respective threshold values of B and A <B can be arbitrarily selected.

FIG. 12 shows a quinary output in an encoded format using a comparator 81. Encoded outputs Y1, Y2, and Y3 are output for inputs A and B, respectively. Table 1 shows the relationship between input and output in this case.

FIG. 13 shows the nxm encoding means 58 (shown in FIG. 9).
An example of the configuration will be described.

The nxm encoding means 58 controls the encoder 91 by using ROM or PLD.
And implements, for example, a 3 × 3 encoding unit. Table 2 shows the relationship between the input and output of the encoder 91. Here, the outputs 01 to 09 may be in a decoding format or an encoding format.

FIG. 14 shows an example of the configuration of the comparing means 4. In FIG. 4, the input is a differential / ternary signal in a decode format, whereas in this embodiment, the input is a differential / n-ary signal in an encode format. This is an example in the case of performing. The input signals A, B and C are constituted by two comparators 95 and 96 and an OR circuit 97.

FIG. 15 shows an electronic endoscope apparatus 101 to which the second embodiment is applied, for example.

The illustrated electronic endoscope apparatus 101 includes an electronic endoscope (hereinafter, referred to as an electronic scope) 102 and the electronic scope 1.
02, a light source device 103 that supplies illumination light, a video signal processing circuit 104 that performs signal processing on the electronic scope 102,
The video signal processing circuit 104 comprises a color monitor 105 for displaying a video signal of a predetermined format in color.

In the electronic scope 102, a light guide 107 serving as an illumination light transmitting means is inserted into an elongated insertion portion 106, and a light guide connector at a rear end (input end) of the light guide 107 can be connected to the light source device 103. It is.

In the light source device 103, the white light of the white lamp 108 is condensed by the condenser lens 109 and is irradiated on the incident end face of the light guide 107. The illumination light transmitted by the light guide 107 is emitted toward the subject 111 from the emission end face. The subject 111 illuminated with the irradiation light is imaged by the imaging lens 112 on the CCD 113 as a solid-state imaging device.

On the front of the CCD 113, a mosaic filter 11 for color separation
4 are provided, and color separation is performed for each pixel.

The CCD 113 is a driver 115 in the video signal processing circuit 104.
Is applied via a signal cable, a signal that is photoelectrically converted by the application of the drive signal, and is read as a charge is input to the pre-processing circuit 121. The pre-processing circuit 121 performs signal processing for separating a luminance signal Y and a line-sequential dye signal R-Y, B-Y (represented by C).
After being converted to digital signals by converters 122 and 123,
These are input to the frame memories 124 and 125, respectively.

The signals temporarily stored in the frame memories 124 and 125 are simultaneously read, converted into analog signals Y and C via D / A converters 126 and 127, respectively, and input to the post-processing circuit 128. This post-processing circuit 128 is provided with a color difference signal C.
And an NTSC encoder, outputs a composite video signal, and displays a subject image on the color monitor 105.

The above-mentioned frame memories 124 and 125 are normally written and read in a predetermined one frame period. That is, writing and reading are performed at a period of 1/30 [sec] of the NTSC system, and the color monitor 105 displays a moving image.

By the way, the motion detection circuit 41 of the second embodiment applied to the fee 101 is formed by also using the frame memory 124 for the signal obtained by A / D converting the luminance signal Y.

Thus, the quantification means forming this motion detection circuit 41
The output of 47 is input to the timing generator 131. This timing generator 131 is
When the freeze switch SW is turned on by the signal M corresponding to the amount of motion outputted from the controller 115, the period of the trigger signal T for performing the reading to the driver 115 is changed according to the magnitude of the signal. That is, in the case of the signal M when the amount of motion is large, the trigger signal T is shortened and output to the driver 115. In response, the driver 115 reads a signal from the CCD 113 in a short charge accumulation time, and the read signal is written to the frame memories 124 and 125. When the writing is completed, the timing generator 131 outputs a signal for inhibiting the writing for a certain period to the frame memories 124 and 125 and holds the freeze mode.

Therefore, the apparatus 101 can obtain a frozen image with little image blur during the freeze operation according to the movement of the subject 111 or the like.

When the charge accumulation time is changed, an interline transfer CCD can be used as the CCD 113. When a trigger signal T is input, the signal of the light receiving unit is transferred to the transfer unit, and then the readout from the transfer unit is performed. Just do it.

In the case of another method, smear may be prevented by performing high-speed reading, light may be blocked by a liquid crystal shutter, or illumination light on the light source side may be blocked.

Since the motion detection circuit of the present invention is based on the differential operation, it has been confirmed that the larger the blur, the larger the detected value tends to be for the focus blur. Is applicable.

Note that the principle of motion detection shown here can be applied and implemented regardless of the digital or analog signal form.

[Effects of the Invention] As described above, according to the present invention, for each image signal to be subjected to motion detection, a difference signal of a pixel adjacent to the image signal at a predetermined sampling period is obtained, and is converted into an n-value to perform motion detection. Since the comparison is made between the images and the compared output signal is quantified, the movement of the image signal can be quantified with high accuracy.

Further, as compared with the conventional method using the inter-frame difference signal, it is possible to reduce the circuit scale, achieve low cost, and achieve a high detection rate.

[Brief description of the drawings]

FIGS. 1 to 7 relate to a first embodiment of the present invention.
FIG. 2 is a basic configuration diagram of the first embodiment, FIG. 2 is a block diagram showing a configuration of an encoding unit, FIG. 3 is a configuration diagram of a difference / n-value conversion unit, and FIG. 4 is a specific configuration of a comparison unit. FIG. 5, FIG. 5 is a diagram for explaining the operation of the comparing means, FIG.
FIG. 9 is an explanatory diagram showing the detection characteristics of the first embodiment, FIG. 8 is a block diagram showing the configuration of the motion detection circuit of the second embodiment of the present invention, and FIG. FIG. 10 is a block diagram showing the configuration of the means, FIG. 10 is a basic configuration diagram of the fourth embodiment of the present invention, FIG. 11 and FIG. FIG. 14 is a diagram showing a configuration of an n × m encoding unit. FIG. 14 is a diagram showing another configuration example of a comparison unit.
FIG. 15 is a configuration diagram showing an electronic endoscope apparatus to which the present invention is applied. 1 ... Motion detection circuit 2a, 2b, 2c ... Input end 3a, 3b, 3c ... Encoding means 4 ... Comparison means 5, ... Quantification means 6 ... Output end, 12 ... LPF 13 ... Delay means 14 ... Difference / n-value conversion means 16 ... Comparator 21,22,23,24,25,26 ... EX-OR circuit 27,28,29 ... OR circuit

Continued on the front page (72) Inventor Katsuyuki Saito 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the O-Limpus Optical Industry Co., Ltd. In Optical Industry Co., Ltd. (72) Inventor Katsuyoshi Sasakawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (72) Inventor Jun Hasegawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (72) Inventor Yudai Nakagawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. Examiner Takashi Matsunaga (56) References JP-A-61-65682 (JP, A) JP-A-61-201585 (JP, A) JP-A-60-106288 (JP, A)

Claims (1)

(57) [Claims] 1. A motion detecting circuit for detecting a motion of a subject image based on an image signal continuously picked up at a predetermined frame / field cycle by an image pickup means, wherein a predetermined period of the continuously picked up image signal is provided. With respect to the first image signal at a predetermined sample period,
A difference signal between adjacent pixels is obtained, and the difference signal
A first difference n-value conversion unit that outputs a signal representing the feature of the first image signal by converting the value into an n-value as the integer, and a predetermined frame / field cycle different from the first image signal A second image signal captured by the image capturing means is obtained at a predetermined sampling cycle interval to obtain a differential signal of adjacent pixels, and the differential signal is set to n as an integer of 2 or more.
A second difference n-value conversion unit that outputs a signal representing the feature of the second image signal by converting the value into a value, and a match between the respective signals output by the first and second difference n-value conversion units; Compare the mismatch, match between the signals,
A motion detection circuit, comprising: comparison means for outputting a signal indicating a period of non-coincidence; and quantification means for quantifying the amount of motion of the subject image based on the signal output by the comparison means.