JPS63117283A - Distance measuring apparatus - Google Patents

Abstract

PURPOSE:To simplify handling during the photographing, by a method wherein an ultrasonic wave receiving section is provided within a wireless microphone carried by a main object and receives a radio wave transmitted from the wireless microphone to measure a distance detecting the presence of an ultrasonic signal. CONSTITUTION:An ultrasonic wave S is transmitted from an ultrasonic wave transmitter 7 of a video camera and collected with an ultrasonic microphone 11 of a wireless microphone 8 carried by a main object to be converted into an ultrasonic signal. A voice near the main object is collected 10 to be converted into a voice signal. After mixed 12 together, these ultrasonic wave signal and voice signal are transmitted 13 as radio wave P. The radio wave P is received 14 and separated 15 into an ultrasonic wave signal Ss and a voice signal Sv. The signal Ss thus separated is checked for the presence thereof with a detector 16 and a detection signal is outputted to a microcomputer (MC)17. A distance measurement signal indicating a distance to the main object is obtained with the MC17 by a computation to move a photographing lens 19 with a lens driving mechanism 18 according to the distance measurement signal thereby adjusting the focus of a video camera on the main object.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a distance measuring device for an automatic focusing device used to focus a photographic lens of a video camera or the like on a subject. be.

[Conventional technology]

FIG. 4 is a diagram showing an example of a conventional distance measuring device.

In the figure, 1 is a video camera, 2 is an ultrasonic unit installed in the video camera 1 that transmits ultrasonic wave S and receives the reflected wave, 3 is the main subject located in front of the video camera l, and 4 5 is a wireless microphone that collects sounds near the main subject and transmits them to the video camera 1 using radio waves Pv; 5 is a bronze subject existing near the main subject 3; and 6 is the background.

Next, the operation will be explained. Ultrasonic waves S are emitted from the ultrasound unit 2 toward the main subject 3.

This ultrasonic wave S is reflected by the main subject 3 and is received by the ultrasonic unit 2 as a reflected wave. With this, the time from when the ultrasonic wave S is emitted from the ultrasonic unit 2 until it is received is calculated, and the path length of the ultrasonic wave is calculated by multiplying the measured time by the speed of sound. By doubling the distance, the distance from the digital camera 1 to the main subject 3 can be measured. Based on this distance measurement signal, the photographing lens of the video camera 1 is moved in the direction of its optical axis so that the video camera 1 is focused on the main subject 3.

At the same time, the sound near the main subject 3 is collected by the wireless microphone 4, and is transmitted as a radio wave Pv to the video camera 1 side and received.

[Problem that the invention seeks to solve]

Since the conventional distance measuring device is constructed as described above, if the ultrasonic wave S etc. is emitted toward the raw subject 3 and the reflected wave is not received from the main subject 3, the range up to the main subject 3 cannot be detected. The distance cannot be measured accurately, and the positional relationship between the optical axis direction of the video camera l and the main subject 3 deviates significantly, and the video camera 1 ends up positioning the copper subject 5 or the background 6 in the center of the screen. Since the reflected waves of the ultrasonic waves S from the broken object 5 or the background 6 are received and measured, the video camera 1 is in focus on the copper object 5 or the background 6, and the main object is There is a problem in that the subject 3 becomes out of focus when photographed with a video camera, and the subject 3 becomes blurred. It is necessary to change the direction and take pictures, and especially when the main subject 3 is moving, it is necessary to move the video camera 1 in accordance with the movement of the main subject 3, which is very difficult to handle. There was a problem.

This invention was made to solve the above-mentioned problems, and it is possible to always accurately measure the distance to the subject even if the subject is not positioned in the center of the video camera screen. The purpose is to obtain a distance measuring device.

[Means for solving problems]

The distance measuring device according to the present invention receives ultrasonic waves emitted from the distance measuring side by a wireless microphone means on the distance measuring side, transmits the ultrasonic reception signal as radio waves, and transmits the ultrasonic waves on the ranging side. The receiving means receives the signal and converts it into a received signal, measures the time from receiving the ultrasonic wave to obtaining the received signal, and calculates the PTR constant based on this 1-hour measurement to obtain the distance measurement signal. This is what I did.

[For production]

The distance measuring device in this invention has a distance measuring side and a distance measuring target 9111.
The time it takes for radio waves to be sent and received is almost negligible compared to the time it takes for ultrasonic waves to be sent and received, so if you multiply the measurement time by the speed of sound, that value is equal to the distance measurement. Get a signal.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram for explaining the outline of an apparatus according to an embodiment of the present invention. In this figure, parts with the same symbols as those in FIG. 4 are the same as those in the conventional system, and their explanation will be omitted. 7 is provided in the video camera 1;
5.8 is carried by subject 3, collects and mixes ultrasonic waves and sounds, and transmits radio waves P containing these components. A wireless microphone 9 is provided on the video camera 1 and transmits radio waves P.
The reception signal processing circuit receives and measures the distance, and also inputs the start signal for transmission from the ultrasonic transmitter 7.

FIG. 2 is a more detailed block diagram of the wireless microphone 8. In the figure, 10 is a normal voice wave v'f! :Audio microphone that collects sound and converts it into audio signal, 1] is ultrasonic S
12 is a mixer that inputs the audio signal from the audio microphone 10 and the ultrasound signal from the ultrasound microphone 11, mixes them, and outputs them; 13; is a transmitter that converts the mixed signal output from the mixer 12 into radio waves P and transmits them.

FIG. 3 is a roughly detailed block diagram of the received signal processing circuit 9 and the like. In the figure, 14 is a receiver/demodulator that receives the radio wave P from the wireless microphone 8 and demodulates it into a mixed signal, and 15 is a receiver/demodulator that converts the mixed signal into an ultrasonic signal Ss and an audio signal Sv.
16 is a detector for detecting the presence or absence of the ultrasonic signal Ss from the separator 15; 17 is a microcomputer which inputs a transmission start signal from the ultrasonic transmitter 7 when transmitting the ultrasonic wave S; , measure the time from this input point,
The measurement is stopped when the detection signal is input from the detector 16, and a predetermined calculation is performed based on this measurement time to output a distance measurement signal. 18 is a well-known lens drive mechanism that inputs the distance measurement signal; 19 is a video camera / lens;
By the lens drive mechanism 18! It is moved in the direction of the l1 element axis.

Next, the operation of this embodiment will be explained. An ultrasonic wave S is emitted from an ultrasonic transmitter 7 of a video camera l, collected by an ultrasonic microphone 11 of a wireless microphone 8 carried by a main subject 3, and converted into an ultrasonic signal. or,
At this time, the sounds around the main subject 3 are collected by the audio microphone IOK and converted into audio signals. These ultrasonic signals and audio signals are mixed by a mixer 12 and then converted into radio waves P by a transmitter 13 and transmitted to the video camera 1 side. This radio wave P is received by the receiver/demodulator 14 of the received signal processing circuit 9, mixed into a mixed signal, and separated by the separator 15 into a superfrequency signal Ss and a voice signal Sv. The presence or absence of the separated ultrasonic signal S8 is detected by the detector 16, and if detected, a detection signal is output from the detector 16 to the microcomputer 17.

10,000, microcomputer], 7 starts measuring time from the time when the transmission start signal is input from the ultrasonic transmitter 7 when transmitting the ultrasonic wave S, and starts measuring time from the time when the detection signal is input from the detector 16. stop. This allows ultrasonic S
The time from when it is transmitted until it is received as a radio wave P is measured, and since the speed of the radio wave P is incomparably much greater than the speed of the ultrasonic wave S, the measurement time is preset to correspond to the speed of sound. By multiplying the distance by the value, a distance measurement signal indicating the distance to the main subject 3 can be obtained by calculation by the microcomputer 17. The lens drive mechanism 18 moves the photographing lens 19 in response to this distance measurement signal, and the focus t of the video camera 1 is
-Adjust to main engine object 3.

Note that in the above embodiment, the audio microphone 1o and the ultrasonic microphone 1
1 is different, but even if the same microphone is used, the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, an ultrasonic reception section is provided in a wireless microphone carried by the main subject, receives radio waves transmitted from the wireless microphone, and detects the presence or absence of an ultrasonic signal. Since it is configured to measure the distance, the distance from the video camera to the main subject can be measured no matter how far the main subject is within the screen of the video camera.
Since the video camera is focused on the main subject, there is no need to consider the positional relationship between the main subject and the video camera, and the effect is that handling of the video camera during shooting can be simplified.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining one embodiment of the present invention,
@ Figure 2 is a block diagram showing an example of the wireless microphone in Figure 1, Figure 3 is a block diagram showing an example of the received signal processing circuit, etc. in Figure 1, and Figure 4 is an explanatory diagram for explaining the conventional example. It is. In the figure, 7 is an ultrasonic transmitting means, 8 is a wireless microphone means, 9 is a receiving signal processing circuit, 10 is an audio microphone, 1
1 is an ultrasonic microphone, 12 is a mixer, 13 is a transmitter, 14
15 is a receiver/demodulator, 15 is a separator, 16 is a detector, and 17 is a microcomputer. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) Ultrasonic transmitting means for transmitting ultrasonic waves from the ranging side;
wireless microphone means for receiving the ultrasonic waves on the distance measuring side, converting the ultrasonic reception signals into radio waves and transmitting them to the distance measuring side; and receiving the radio waves from the wireless microphone means on the distance measuring side. a receiving means for converting into a signal, and measuring the time from the time when the transmission start signal is input from the ultrasonic transmitting means to the time when the received signal is input from the receiving means when transmitting the ultrasonic wave, and the measured time a calculation means for performing a predetermined calculation based on the above to obtain a distance measurement signal indicating the distance from the distance measurement side to the distance measurement target side. (2) The wireless microphone means includes a microphone that converts surrounding sounds into audio signals and converts the ultrasonic waves into the ultrasonic reception signals, and a mixer that mixes the audio signals and the ultrasonic reception signals. , a transmitter that converts the mixed signal from the mixer into the radio wave and transmits it, and the receiving means includes a receiver/demodulator that receives and demodulates the radio wave, and a receiver/demodulator that receives the demodulated signal from the receiver/demodulator. It consists of a separator that separates the ultrasonic signal and the audio signal, and a detector that detects the ultrasonic signal from the separator, and the calculation means inputs the detection signal from the detector as the received signal. A distance measuring device according to claim 1, characterized in that: