JPH0542524Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device that captures an image of a moving object and detects the position of the object, and in particular controls image subtraction processing according to the moving speed of the object. Regarding technology.

[Conventional technology]

As such a position detecting device for a moving object, there is a conventional device shown in FIG. 3, for example. (Unexamined Japanese Patent Publication 1986-
(See Publication No. 153774).

In this method, a moving object is imaged by an imaging device 1, the image data is sequentially stored in an image memory 2, and a subtraction processing unit 3 inputs a first image at a certain point in time and a second image N frames later, and then both The frame difference between the images is determined, a difference image of only the moving object is generated with the background image removed, and the position calculation unit 4 calculates the position of the object based on this difference image, and the data output unit 5 calculates the position of the object.
It outputs position data from.

[Problem that the invention attempts to solve]

By the way, in such a conventional position detection device, when inputting a second image N frames after the first image, the value of N that determines the second image is fixed to a predetermined value. In addition, if the amount of movement of the object per unit time is extremely small, that is, if the moving speed of the object is extremely slow, the moving object will also be removed as a stationary background image, and an image of the moving object will not be generated. I can't do it,
Therefore, there was a problem that the position of the object could not be detected.

Therefore, the purpose of the present invention is to make the value of N for determining the second image variable, to generate the movement trajectory of the object as an image even when the movement speed of the object is slow, and to reliably perform the position detection process. The goal is to make it possible.

[Means for solving problems]

In order to achieve the above object and solve the problems of the prior art, a moving object position detecting device according to the present invention includes a moving amount detecting means for detecting the moving amount of the object based on a difference image, When the amount of movement is less than a predetermined threshold, reprocessing command means increases the N value and commands the subtraction processing means to perform reprocessing.

[Effect]

According to the present invention, when the amount of object movement per unit time is large, the N value can be set to a small value to obtain a difference image based on two images that are closer in time. On the other hand, when the amount of object movement becomes smaller, N
The value is changed to a large value and a difference image based on two temporally separated images is obtained. Therefore, even if the moving speed of the object is slow, it is possible to input two temporally separated images and perform subtraction processing (frame difference processing) to leave the moving object on the image data.

〔Example〕

Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 shows an example of a moving object position detection device according to the present invention.

In the figure, 11 is a supercooled floating furnace that heats and cools objects in outer space, 12 is an object that is heated and cooled in this supercooled floating reactor 11, 13 is a heating lamp, and 14 is an auxiliary light for imaging the object. , 15 is an imaging device, and 16 is an image processing section. This image processing section 16 includes an image memory 17 that stores image data.
, the first image captured at a certain time t, and N
A subtraction processing unit 18 that calculates a frame difference with the second image after the frame, a position calculation unit 19 that detects the position of the object based on the difference image obtained by this subtraction processing unit 18, and outputs the calculated position data. a movement amount detection section 21 that detects the amount of movement of the object based on the difference image obtained by the subtraction processing section 18;
When the detected movement amount is less than a predetermined threshold value, a reprocessing command section 22 is provided that changes the value of N to a larger value and commands the subtraction processing means to perform reprocessing.
Note that 23 is a control section that controls each section of the image processing section 16.

Next, the operation of this apparatus will be explained according to the processing flow shown in FIG.

First, the control unit 23 selects either area detection processing or frame difference processing by processing selection (S
-1).

The area detection process is a process performed to image the object 12 in a situation that does not include the background and to determine the accurate position of the object. In this process, in order to avoid imaging the background, the heating lamp 13 inside the furnace
lights up the auxiliary lamp 14 when it is off,
An image of only the object 12 is captured and the coordinates of the object are detected by processing such as template matching [(S-2), (S-3), (S-4)].

On the other hand, frame difference processing is processing for obtaining movement position data for an object. In this process, it does not matter if the background is imaged, so the heating lamp 13
Processing can be performed regardless of whether it is ON or OFF. In this process, the subtraction processing unit 18 inputs the first image and the second image after N frames from the image memory 17 as two images [(S-5), (S-6)],
Frame difference processing is performed to generate a difference image (S-7). At this time, the second image is input, for example, one frame time (33 ms) after the first image is input (therefore, N=1). Next, the movement amount detection section 2
1 binarizes the differential image using a certain threshold value, and determines whether the area of the movement trajectory is sufficient by comparing the threshold values. If it is not sufficient (when the amount of movement is small), a command signal from the reprocessing command unit 22 is used. Based on the subtraction processing unit 18
increases the value of N, inputs the second image again, and performs processing to obtain a frame difference (S-8).
At this time, the simplest way to change the value of N by the reprocessing command unit 22 is to uniformly change N=N+1, N=N+2, N=
Although the method is to set N+3, if more detailed numerical settings are to be made, the value of N may be changed in accordance with the amount of movement so as to have a tendency that is inversely proportional to the amount of movement.

Next, if the area of the movement trajectory is sufficient (if the amount of movement is large), the position calculation unit 19
The movement vector of the object is determined by calculating the center of gravity in step 2 (S-9). Then, using the position data of the object 12 obtained by the area detection described above,
The new coordinates of the object 12 after the movement are calculated. After this, the second image is replaced with the next first image and the second image input is repeated [(S-10), (S
−11)]. If the position of the object is detected accurately, the object can be heated and cooled accurately.

[Effect] As explained above, when the moving amount of the object is less than a predetermined threshold, the moving object position detecting device according to the present invention increases the value of N that determines the second image, and then repeats the first image. Since subtraction processing is performed between images, it is possible to reliably leave a movement trajectory on the difference image even if the object is moving at an extremely slow speed.
It becomes possible to detect the position of an object.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a configuration example of a position detection device according to the present invention, FIG. 2 is a flow chart showing an operation example of the position detection device according to the present invention, and FIG. 3 is a configuration example of a conventional position detection device. FIG. 12...Object, 15...Imaging device, 17...Image memory, 18...Subtraction processing unit, 19...Position calculation unit, 21...Movement amount calculation unit, 22...Reprocessing command unit.

Claims (1)

[Scope of utility model registration request] comprising: an imaging device; and a subtraction processing means for inputting a first image captured by the imaging device at a certain point in time and a second image N frames after the first image to obtain a frame difference between the two images. , a moving object position detection device that detects the position of a moving object based on a difference image obtained by the subtraction processing means, comprising a movement amount detection means that detects a movement amount of the object based on the difference image; 1. A position detection device for a moving object, comprising: reprocessing command means for increasing the value of N and commanding a subtraction processing means to perform reprocessing when the amount of movement is less than a predetermined threshold.