JPH0522194B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a weather sensor device that detects rainfall and snowfall at a desired spatial position and measures the amount of rain and snowfall, and in particular, relates to a meteorological sensor device that detects rainfall and snowfall at a desired spatial location and measures the amount of rain and snowfall, and in particular, detects rainfall and snowfall at a desired spatial location. This invention relates to a snowfall measurement device.

[Prior Art] FIG. 1 is a block diagram showing an embodiment of the present invention. If the synchronization signal 15 is omitted in FIG. ), and since the present invention has this separately filed invention as a prior art, the separately filed invention will be explained as a conventional device using FIG.

In FIG. 1, 1 is an electric circuit for a projector, 2 is a light source, 3 is a lens for a projector, 4 is a polarizer, 5 is a projected light beam, 6 is a reflective object, 7 is reflected light, and 8
9 is a light receiving lens, 9 is a polarization separator, 10 is a vertical light receiving element, 11 is a horizontal light receiving element, 12 is a vertical receiver, 13 is a horizontal receiver, 14 is a signal processing section, and 8 to 13 are the light receiving device. It is configured.

A polarized light beam 5 is projected, reflected light 7 from a reflecting object 6 is received by a light receiver, and is separated into a vertically polarized light component and a horizontally polarized light component by a polarization separator 9, and the vertically polarized light component is sent to a vertical light receiving element. The horizontally polarized light component is converted into an electrical signal by a horizontal light receiving element 11.

The outputs of the vertical light receiving element 10 and the horizontal light receiving element 11 are amplified by a vertical receiver 12 and a horizontal receiver 13, respectively, and input to a signal processing section 14.
The signal processing section 14 processes the output of the vertical receiver 12 and the output of the horizontal receiver 13 to determine the nature of the reflecting object.

For example, the output of the horizontal receiver 13 is the output of the vertical receiver 12.
If the output of the reflective object 6 is sufficiently small compared to the output of
This means that no scattering of the plane of polarization occurs, and therefore it can be determined that the reflecting object 6 is not snow.

[Problems to be Solved by the Invention] Since the conventional rainfall and snowfall measuring device as described above is configured as described above, noise is not mixed into the output of the vertical receiver 12 and the output of the horizontal receiver 13. However, there is a problem in that the measurement accuracy is reduced.

That is, external light other than the reflected light 7 with respect to the projected beam 6 may be input to the light receiving elements 10, 11, or may be input to the light receiving elements 10, 11, the receivers 12, 1.
Noise generated in step 3 is mixed in and reduces measurement accuracy.

In order to remove such noise, conventional bandpass technology modulates the intensity of the light beam 5 projected by the light source 2 at a specific frequency and extracts only the output of the modulated frequency component from the outputs of the receivers 12 and 13. Although a filter is used, there are problems in that the device is complicated and noise removal is not sufficient.

The present invention was made in order to solve the above-mentioned problems in conventional devices, and aims to provide a rainfall and snowfall measurement device that has a simple configuration, can sufficiently remove noise, and can perform accurate measurements.

[Means for Solving the Problems] The rainfall and snowfall measuring device according to the present invention pulse-modulates a light beam projected from a projector, and from the receiver output at the time when the reflected light for the pulse-modulated light beam is input, We decided to remove noise by subtracting the receiver output at the time when no reflected light was input to the pulse modulated light beam.

[Operation] The receiver output at the time when the reflected light for the pulse modulated light beam is not input is noise, and the receiver output at the time when the reflected light for the pulse modulated light beam is input is the detection signal with noise superimposed on it. By subtracting from , it becomes possible to extract only the alarm signal.

[Examples] Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, in which reference numeral 15 denotes an electric circuit 1 for a projector and receivers 12, 1.
This is a synchronization signal for synchronizing with 3. The circuits other than those related to the synchronization signal 15 are as already described.

FIG. 2 is a block diagram showing the operation of the synchronization signal 15 in FIG. 1. In FIG. 2, the same reference numerals as in FIG. Horizontal amplifier circuit in the receiver 13, 15a is a light source modulation pulse, 15b is a signal gate pulse of the synchronization signal 15, 15c is a noise gate pulse of the synchronization signal 15, 16 is a synchronization circuit, 17 is a modulation circuit, 18 ,19,23,
24 is an AND gate, 20 is a first vertical hold circuit, 21 is a second vertical hold circuit,
22 is a vertical subtracter, 25 is a first horizontal hold circuit, 26 is a second horizontal hold circuit, and 27 is a horizontal subtracter.

In the correspondence between Figure 1 and Figure 2, 16,1
7 constitutes the floodlight electric circuit 1, 12a, 18
~22 constitute the vertical receiver 12, 13a, 23
27 constitute the horizontal receiver 13.

Each AND gate, together with the hold circuit following it, forms a so-called sample-and-hold circuit, and holds the peak value of the output of the amplifier circuits 12a, 13a at the sample time.

FIG. 3 is a waveform diagram showing the voltage waveforms of each part in FIG. 2, and the operation of the horizontal receiver 13 is
Since the operation is similar to that of 2, only the part related to the vertical receiver 12 is shown in FIG.

In Fig. 3, 15a, 15b, 15c are the second
Represents the signal waveforms of the signals with the same symbols in the figure, 12s,
18s, 19s, 20s, 21s are 12 each
The output waveforms of a, 18, 19, 20, and 21 are shown.

The light source modulation pulse 15a has a pulse repetition period T
generates a pulse with pulse width τ. When the light source 2 emits light by being modulated by this pulse, the output 12s of the vertical amplifier circuit 12a becomes as shown in FIG. The bottom part of 12s is noise, and the reflected wave appears as a pulse wave superimposed on the noise every time light is projected.

The time difference t1 between the rising points of the light source modulation pulse 15a and the reflected wave pulse is mainly caused by the vertical amplifier circuit 1.
Therefore, the signal gate pulse 15b is designed to be generated with a phase delayed by t1 from the light source modulation pulse 15a. Furthermore, since the reflected wave pulse continues for a considerable time even after the light source 2 stops emitting light, sampling for noise must be performed after the reflected wave pulse has sufficiently attenuated.

In the example shown in FIG. 3, the noise gate pulse 15c is delayed by t2 from the light source modulation pulse 15a. The outputs of AND gates 18 and 19 are each 1
As shown in 8s and 19s, hold circuit 2
The outputs of 0 and 21 are as shown in 20s and 21s, respectively, and the subtracter 22 subtracts 21s from 20s to remove the noise, and the peak value of the signal can be input to the signal processing unit 14.

[Effects of the Invention] As explained above, the present invention pulse-modulates the light beam projected from the projector, and from the receiver output at the time when the reflected light for the pulse-modulated light beam is input, the light beam for the pulse-modulated light beam is Since we decided to remove noise by subtracting the receiver output at the time when reflected light is not input, we can use a simple configuration to prevent the intensity of reflected light from raindrops, snowflakes, etc. from being affected by noise. In addition to being able to obtain accurate data, it is also possible to determine not only rain or snowfall, but also to distinguish between day and night by comparing noise levels, and to determine weather conditions such as whether it is sunny or cloudy. This has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing the operation of the synchronizing signal shown in FIG. 1, and FIG. 3 is a waveform diagram showing the voltage waveforms shown in FIG. 2. 1... Electric circuit for floodlight, 2... Light source, 3...
Emitter lens, 4...Polarizer, 5...Light beam, 6...Reflecting object, 7...Reflected light, 8...Lens for light receiver, 9...Polarization separator, 10...Vertical light receiving element, 11 ... Horizontal light receiving element, 12 ... Vertical receiver, 13 ... Horizontal receiver, 12a ... Vertical amplifier circuit, 13a ... Horizontal amplifier circuit, 14 ... Signal processing section, 15a ... Light source modulation pulse, 15b ... ...Signal gate pulse, 15c...Noise gate pulse, 20...First vertical hold circuit, 21...
Second vertical hold circuit, 22... Vertical subtracter, 25... First horizontal hold circuit, 26...
Second horizontal hold circuit, 27...Horizontal subtractor. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Projecting a light beam polarized to a predetermined polarization wavefront into the air, and receiving reflected light that is reflected by a reflective object such as raindrops or snowflakes present within the light beam. The received reflected light is separated into a vertically polarized component and a horizontally polarized component whose polarization direction differs by 90 degrees from the vertically polarized light.The vertically polarized component is detected by a vertical photodetector, and the horizontally polarized component is detected by a horizontal photodetector. Detected with
In a rainfall and snowfall measurement device that inputs the outputs of the vertical light-receiving element and the horizontal light-receiving element and performs signal processing to determine the properties of the reflective object, means for generating a light source modulation pulse of a predetermined pulse width at a predetermined pulse repetition period. , means for modulating the emitted light beam with the light source modulation pulse; means for generating a signal gate pulse delayed from the light source modulation pulse by a time corresponding to a delay time by predetermined electric circuits on the light emitting side and the light receiving side; Means for generating a noise gate pulse within a phase that is not affected by light projection within the pulse repetition period, and sampling the output of a vertical amplification circuit for amplifying the output of the vertical light receiving element using the signal gate pulse to its peak value. a first vertical hold circuit that holds the output of the vertical amplifier circuit; a second vertical hold circuit that samples the output of the vertical amplifier circuit using the noise gate pulse and holds the peak value; a vertical subtracter that subtracts the output of the second vertical hold circuit, and a first horizontal hold circuit that samples the output of the horizontal amplifier circuit that amplifies the output of the horizontal light receiving element using the signal gate pulse and holds its peak value. , a second horizontal hold circuit that samples the output of the horizontal amplifier circuit using the noise gate pulse and holds its peak value; and subtracts the output of the second horizontal hold circuit from the output of the first horizontal hold circuit. A rainfall/snow measurement device comprising: a horizontal subtractor; and a signal processing section that inputs the output of the horizontal subtracter and the output of the vertical subtracter and performs signal processing.