JPH02236787A - State change detector - Google Patents

Abstract

PURPOSE:To improve the reliability of state change detection by image-picking up a monitor object at prescribed time intervals, calculating a differential value between plural continuous image-picked up pictures for each picture element and executing the cumulative addition of this differential value for each picture element. CONSTITUTION:To an n-pieces of original pictures to be image-picked up and inputted at certain time intervals by an ITV camera 11, smoothing process is executed by a preprocessing circuit 13 for noise reduction. Next, in a differential circuit 16, difference is obtained between the continuous pictures out of the n-pieces of the pictures and the (n-1)-pieces of differential pictures are prepared. In a cumulative adder circuit 17, the total sum of the differential value for each picture is calculated to these (n-1)-pieces of the differential pictures. Then, a cumulative added picture is prepared and a state change area is extracted. Thus, even when liquid leaks from a pipe, etc., in a plant, etc., namely, even when a state change is limited in the small area, the state change can be detected with the satisfactory reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a state change detection device for detecting changes in a monitored object whose shape, position, and state change over time.

[Conventional technology] Conventionally, in this type of state change detection device, the difference between a reference image and an original image captured by an imaging means such as an ITV camera was taken, and the difference image was used to detect a change. . FIG. 4 shows a state change detection device disclosed in, for example, Japanese Unexamined Patent Publication No. 62-147888, in which (1) is an original image frame buffer, (2) is a reference image frame buffer, and (3) is a difference image {191 calculation circuit, <4> is a difference image frame buffer, 5) is a projection circuit, <6> is a comparison circuit, and (7> is a determination circuit.

The method for detecting changes is to use a difference image calculation circuit (1 in 3).
In an irregular difference image, a projection circuit (5
〉, the difference image is projected in the X-axis and y-axis directions, and a comparison circuit (6〉) sets an arbitrary threshold value for each projection data, and if there is data exceeding the threshold value, , the determination circuit (7) determined that there was a change.

[Problems to be Solved by the Invention] Since the conventional state change detection device is configured as described above, even when there is a state change as shown in FIG. If the difference in the brightness of the change location (9) is small, or if the brightness of the state change location (9) itself is small, the difference image with stiffness 1 and luster 1 between the background (8) and the state change location (9) will be Figure 5 (b) and (C)
As shown in the figure, the X-axis and y-axis projection data A.
B also becomes very small, and the set threshold 8B, B
[There is no data exceeding +, so it is determined that there is no change. Moreover, the threshold value Aa. If Bll is made small, it will be determined that there is an abnormality not only at the state change location <9> but also for noise, etc. Furthermore, since the monitored object moves at high speed,
When the state change is a small area, or when the monitored object is small and the state change area is a small area, spark-like noise, vibrations of the background object, and background object contours due to quantization errors during A/D conversion may occur. It was difficult to distinguish it from linear noise, etc.

This invention was made in order to solve the above-mentioned problems, and it is used in cases where the state change is in a small area, such as liquid leakage from a valve, etc., or when the object to be monitored is small. It is an object of the present invention to provide a state change detection device that can reliably detect a state change even when the state change area is a small area.

[Means for Solving the Problems] A state change detection device according to the present invention includes an imaging means for imaging an object to be monitored at predetermined time intervals, and a difference between a plurality of consecutive images taken by the second imaging means. The apparatus is equipped with a calculation means for calculating a value for each pixel, and a cumulative addition means for cumulatively adding the difference value for each pixel to the continuous images.

Further, a removing means removes the contour line constituting the background from the cumulative addition image obtained by the cumulative addition means, and the cumulative addition image after the contour line removal is determined according to the moving direction of the monitored object.
An extraction means may be provided that projects in a direction perpendicular to this movement direction and extracts state-change pixels using a predetermined threshold value for each direction.

[Operation] The state change detection device according to the present invention cumulatively adds the difference values of successive images even when the difference in brightness between the background brightness change and the state change location is small, or when the brightness of the state change location itself is small. By doing so, it is possible to enlarge and emphasize the change area, separate the state change location from the background, and obtain a difference image with contrast that can be distinguished from noise.

In addition, even when the state change is in a small area, it removes spark-like noise and linear noise at the contour of the background object that appears due to background object vibrations and quantization errors during A/D conversion. Automatically and reliably detect changing regions using characteristics of state changes.

[Embodiment] Hereinafter, a state change detection/device according to an embodiment of the present invention will be explained with reference to the drawings.

FIGS. 1 and 2 are block diagrams each showing a state change detection device according to an embodiment of the present invention.

In the figure, <l1) is an ITV camera, (l2) is an image input circuit, <l3> is a preprocessing circuit for noise removal, and <1
4〉〈15) is an image memo I that stores consecutive images in sequence.
J 1, image memory 2, (l6) is a differential circuit, (l7)
is the cumulative addition circuit, <1 button is the cumulative addition image memory,
Extract the state change region. Furthermore, <19> is a binarization circuit, <20> is a contour line detection circuit, <21) is a contour line vicinity area removal circuit, (22) is a state change direction projection circuit, and <23> is a region determination circuit. The presence or absence of a state change is automatically determined.

In the state change detection device configured as above,
First, a state change area is extracted using the configuration shown in FIG. That is, for n original images (Fig. 3 (Q)) input from the ITV camera (11) at certain time intervals,
A preprocessing circuit (13) performs smoothing processing to remove noise. In addition, in Fig. 3(n), <90> indicates water leakage, and <8
0) indicates piping. Next, in the differential circuit (l6), n
Differences are taken between consecutive images among the images, and n-1
Create two differential images (Figure 3(b)).The cumulative addition circuit (l7) calculates the sum of the differential values for each pixel that is not present in the n-1 differential images, and An added image is created and the state change area is extracted (Figure 3 (C)).

Next, the configuration shown in FIG. 2 automatically determines whether the state has changed. That is, the cumulative addition image created from n images is subjected to binarization processing using an appropriate threshold value by the binarization circuit (19), and only the components exhibiting temporal changes are extracted (the third Figure (d)). And the contour detection circuit (20)
Separately, the original image input from the image input circuit (12) is differentiated and then binarized to create a contour image (Fig. 3 (e)). Next, the contour line vicinity area removal circuit 〈2
1), the time-varying component image (FIG. 3(d)) is masked by the contour image (FIG. 3(e)). For pixels where there is a contour line (81) constituting the background, the value of the time-varying component image is set to zero, and vibrations in the background environment and A
Noise near the contour line due to quantization error during /D conversion is removed (Fig. 3 (f)). Next, the state change direction projection circuit (
In 22), an image is projected in the direction of the drop by utilizing the directionality of the liquid falling, and a region exceeding a predetermined threshold value is extracted, and a state change candidate region is extracted (Fig. 3, g). For this state change candidate region, a region discrimination circuit <2382 projects in a direction perpendicular to the falling direction (Fig. 3 (h )).

In the above embodiment, the state change determination was automated using the configuration shown in FIG. Changes in status may be visually observed using the .

[Effects of the Invention] As described above, according to the present invention, there is an imaging means for imaging an object to be monitored at predetermined time intervals, and a difference value between a plurality of consecutive images taken by the imaging means is calculated for each pixel. Since the state change detection device is configured with a calculation means that calculates the difference value and a cumulative addition means that cumulatively adds the difference value to each pixel of the continuous image, it is possible to detect leaks with a small rate of change such as water leaks. It can be detected separately from noise, and has the effect of humiliating highly reliable state change detection devices.

Further, the cumulative addition means removes the contour line forming the background from the recorded cumulative addition image, and the cumulative addition image after the contour line removal is divided into the moving direction of the monitored object and the direction perpendicular to this moving direction. By projecting the image and extracting state-changing pixels using a predetermined threshold value in each direction, water leakage, etc.
Changes in conditions that change at high speed can be detected automatically and reliably. Monitoring personnel do not need to constantly monitor the TV monitor as in the past, reducing the burden on the monitoring personnel and improving plant operation. This has the effect of improving monitoring performance, operability, and store reliability.

[Brief explanation of drawings]

FIGS. 1 and 2 are block diagrams showing a state change detection device according to an embodiment of the present invention, and FIGS.
(h) is an explanatory diagram illustrating the operation of a state change detection device according to an embodiment of the present invention, FIG. 4 is a block diagram showing a conventional state change detection device, and FIG. 5 (aXb)
(c) is an explanatory diagram illustrating the operation of each conventional state change detection device. In the figure, (l1) is an ITV camera, (l2> is an image input circuit, (14) and (15) are image memories, (l6) is a difference circuit, (17> is a cumulative addition circuit, and <18> is a cumulative addition image. Memo IJ, (20) is the contour line detection circuit, Ku2
1) is a contour line vicinity area removal circuit, (22) is a state change direction projection circuit, and (23> is an area determination circuit. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) An imaging means for taking images of the object to be monitored at predetermined time intervals, a calculation means for calculating the difference value for each pixel between a plurality of consecutive images taken by this imaging means, and , a state change detection device comprising cumulative addition means for cumulatively adding the difference value for each pixel. (2) a removal means for removing the contour line constituting the background from the cumulative addition image obtained by the cumulative addition means; and a removal means for removing the contour line forming the background from the cumulative addition image obtained by the cumulative addition means; 2. The state change detection device according to claim 1, further comprising an extraction means for projecting the pixel in each direction and extracting the state change pixel using a predetermined threshold value for each direction.