JPS59197810A - How to separate the light detected by the optical sensor from the background light - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating detection light from a background light of an optical sensor, which is a non-contact type sensor.

When using an optical sensor, which is a non-contact sensor, there are advantages, but there are also many disadvantages. One of the drawbacks may be the following.

Generally, there is some background light such as indoor lighting, outdoor sunlight, etc.
If this background light is stronger than the detection light (well, it is difficult to separate the detection light from the background light and it is often impossible to use it).

Furthermore, in optical sensors, it is especially necessary to accurately separate the detected light from the background light, such as in the optical cutting method, which measures the shape of the measured object by irradiating the slit light onto the measured object. is,
Measurement accuracy greatly depends on this separation.

The present invention was developed in view of the above circumstances, and detects the object by intermittently shining the detection light onto the object to be measured and comparing the state of the object when the object is irradiated with the detection light and the state when the object is not irradiated. This is to separate the light from the background light.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the case where the present invention is implemented in an optical sensor related to optical cutting.

In the figure, 1 is a television camera, and the detected light detected by the television camera 1 is digitized by an A/D converter 3.
The data is input to the memory device 4.

Reference numeral 5 designates a light source for the detection light 2, and the light emitter 6 is a laser diode or the like capable of high-speed switching.The light emitter 6 is driven by a drive circuit 7.

The drive circuit 7 and the memory 4 are each connected to a computer 8.
The computer 8 operates the drive circuit 7 intermittently to irradiate the detection light 2 from the light source 5, and the operation of the drive circuit 7 φ) It is designed to import data and perform the necessary processing.

In addition, 10 in the figure is the lens unit 9 (of the television camera 1).
This is a built-in bandpass filter, and 11 is the light source 5.
This is an optical unit.

The image captured by the television camera 1 is a collection of brightness differences of a large number of scanning M lines, and the brightness difference of each scanning line is a digital signal.
The image data is input to the storage device 4 and the captured image for one screen at one point is stored in the storage device 4.

Further, since the light source 5 intermittently projects the detection light 2 (17), the television camera 1 visualizes the state in which the object to be measured is irradiated with the detection light 2 and the state in which it is not irradiated.

Next, suppose that Fig. 2 (a) is the image of 12 or detection light 2 on the 1st image plane, and the brightness of the scanning line n at an arbitrary position is not shown. d).

Figure 2 (b) shows a state where there is no background light, and the detected light 2
The brightness of only the part corresponding to " increases, but in reality, the detection light beam is superimposed on the background light as shown in the same figure (c). Also, in Fig. 2 (2), the detection light beam 2 is the brightness signal of the scanning line n when it is not projected, and if intermittent gating of the detection light is performed for each screen (scanning line - cycle screen), the background light shown in (c) and the brightness signal shown in (d) The brightness signal in (c) and the brightness signal in (d) are compared and the difference is found, and a signal of only the uniform detected light can be obtained as shown in (e). If this is performed for all scanning lines, an image of the detection light separated from the background light can be obtained.

That is, one screen's worth of signals is captured in the memory 4 in the state where the detection light 2 is irradiated, and then the signal for one screen is captured in the memory 4 when the detection light 2 is not irradiated (background light only).
A storage device 41 takes in signals for the screen, compares the signals of both screens, and extracts different parts.

Furthermore, if the wavelength of the detection light 2 is selected to be different from the wavelength of the background light, and the bandpass filter 10 is made to match the detection light 2, the wavelength of the detection light 2 can be detected more accurately. .

Furthermore, light jl! :j As shown in Figure 3, if you repeat step-non-projection for each scanning line and make 1 to 1 images, you will get 1 q of images as shown in Figure 4 (A) (1 in Figure 3). ) indicates a signal for one scanning line).

On both sides, adjacent scanning lines have very similar information except when the detection light is projected (FIG. 4(B)) or when it is not projected (FIG. 4(C)).

Therefore, by comparing the data of adjacent scanning lines,
If you extract the part that is ¥, you will have combined the slit light and the backlight light (Figure 4 (d)). According to this method, when acquiring data, only one screen needs to be imaged, so the measurement time is reduced. and 1ii) reduction of memory.

-1- In one embodiment, a television camera was used as an imaging device, but even if an imaging device using a semiconductor element is used, J
Yes. Furthermore, it goes without saying that the present invention can be implemented in optical sensors other than those using the light cutting method, and any 1iiB i state of the detected light, ty, four-way state, or non-irradiation state may be taken into the storage device first.

As described above, according to the present invention, it is not necessary to perform graphical analysis of imaging, and the detected light can be separated from the background light simply by a comparison operation, so the processing procedure is simple and can be speeded up, and the circuit device can be It can be done simply and the separation accuracy of the detection light can also be improved.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing an embodiment of the present invention, Figure 2 (A)
(b) (c) (d) (e) are explanatory diagrams explaining the separation procedure of the detection light in the same embodiment, Fig. 3 is a timing chart of another actual flow example, and Fig. 4 (a) ( B) (C) (2) is an explanatory diagram illustrating the separation procedure of detection light in the same embodiment. 1 is a television camera, 2 is detection light, 3 is an A/D converter, 4
5 is a storage device, 5 is a light source, 7 is a drive circuit, and 8 is a computer. Figure 2 12 Procedure correction, 8 (method) + 'li
f Falcon display 1982 Patent Application No. 73315 2. Name of the invention: Method for separating the detected light of an optical sensor from the background light; No. 17 Yahagi Daini Building, 3-5-3 Uchikanda, Chiyoda-ku, Tokyo July 6, 1981 (Shipping date 58.7.26) 6 Subject of amendment Mingyo II+'! In the drawing section of t, qi Q: jp Akira column, drawing 7 hook 11, the contents of page 6, line 8 to line 13 of the same page, ``Figure 1 is...'' is as follows. to correct. "Figure 1 is a schematic diagram showing an embodiment of the present invention, and Figure 2 (a), (b), (c), (d), and (e) show the /A separation procedure of the detection light in the same embodiment. Figure 2 is an explanatory diagram to explain (
A) shows the captured image 1nj, and Fig. 2 (B) and (C) show the brightness signals of the scanning lines at arbitrary positions, respectively.
Figure 2 (b) is a state assuming that there is no background light;
131) shows the state where there is background light, Fig. 2 (←) shows the state where no detection light is projected, and Fig. 2 (E) shows the state where there is no background light.
It shows the difference between the brightness signals shown in Figures (C) and (D). Furthermore, FIG. 3 is a timing chart of another embodiment of the present invention, and FIGS. 4 (a), (b), (c), and (d) are explanations explaining the decomposition procedure of the detected light in the same embodiment S. Figure 4 (@) is an image obtained by repeating projection and non-projection for each scanning line, Figure 4 (b) is when the detection light is projected, and Figure 4 (c) is the image taken when the detection light is projected.
is when the detection light is not projected, Figure 4 (D) is the Thrift light and back, 1
;: Separated state! 4 respectively. -1 (11) Correction of drawings Figure 2 (a) (o) H (ko) (po) should be corrected as shown in the attached drawing.

Claims (1)

[Claims] l) The detection light of an optical sensor is characterized in that the detection light is intermittently irradiated onto the object to be measured, and the detection light is extracted by comparing the flfl images during irradiation and non-irradiation. Separation method.