JPS62167645A - Recorder - Google Patents

Abstract

PURPOSE:To attain the start and stop of a video recording in response to the sound level by providing a sound level detection means detecting the sound level and outputting a signal in response to the level and a recording means starting or stopping the video recording in response to the signal of the detection means. CONSTITUTION:A controller 5 includes, e.g., a subtractor 6 and a delay circuit 9, detects a difference between the sound level delayed by a prescribed time AT and the sound level not delayed, eliminate a stationary noise component and detects a signal corresponding to the fluctuation of the sound level. A signal corresponding to the fluctuation is compared with a prescribed value betaby a post-stage comparator 7 and when the fluctuation reaches the prescribed value or over, a counter 8 is reset. When the counter 8 is reset, an output inversion of Qn rises from and L level to an H level and the video recording is started. Then the counter 8 counts a CLOCK signal and when it reaches a prescribed value and the output inversion of Qn descends to the H level, the video recording is stopped. Since the sound and video recording are applied in response to the fluctuation of the sound level in this way, the device is used even at an environment with much noise stationarily.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a recording device, and particularly to a recording device that controls recording timing based on audio level.

<Prior Art> Conventionally, a recording device suitable for monitoring, for example, has been used in a configuration in which an imaging device and a recording device are combined.

<Problems to be Solved by the Invention> However, with conventional recording devices, there is a natural limit to the recording time due to the limited number of recording media for continuous recording for monitoring purposes, and it is difficult to determine the timing of recording. If recording is performed intermittently at fixed time intervals, recording will be missed and the recording device will not be sufficient.Also, even if continuous recording can be performed for a long time, recording will continue as the recording time increases. The amount of media has also increased, and there have been problems in that it takes time to search for a desired signal in order to reproduce it later from the recording medium.

It is an object of the present invention to provide a recording device that solves these conventional problems.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a sound level detection means for detecting the sound level and outputting a signal according to the level, and a signal of the detection means. The apparatus is characterized by comprising a recording means that starts or stops video recording in response.

<Operation> In the above configuration, video recording is started or stopped depending on the audio level.

Embodiment FIG. 1 is a block diagram of a first embodiment of the present invention. In FIG. 1, 1 is a light receiving circuit, and 2 is a detection circuit for detecting the level of an audio signal from a microphone 2'. 3 is an imaging device, even one for still images such as a camera,
It may also be a continuous image camera such as a VTR camera. Further, the imaging device may be one using a silver halide film or one using an image sensor. 4 is a recording device. The light receiving circuit 1 and the audio level detecting circuit 2 may be provided externally separately from the imaging device 3 and the recording/recording device 4, respectively. Further, as will be described later, instead of separately providing the light receiving circuit 1 and the audio level detecting circuit 2, the light receiving output and audio output of the imaging device 3 and the recording/recording device 4 may be used. Further, as the recording/recording device 4, a VTR, a still video, or the like may be used, but it is not necessarily necessary to have a recording function, but it is sufficient to have a recording function.

Reference numeral 5 denotes a control device that generates a control signal e1 for controlling the operations of the imaging device 3 and the recording/recording device 4 based on the outputs of the light receiving circuit 1 and the audio signal level detection circuit 2.

Note that the recording/recording device 4 is configured to perform recording when the control signal e1 is at H level.

Next, the operation of the control device 5 that controls the recording/recording device 4 in accordance with the output of the audio signal level detection circuit 2 will be explained using the flowchart shown in FIG.

FIG. 2 is a flowchart showing the operation of the control device 5.

#1: Input the signal level a obtained by the audio signal level detection circuit 2 to the control device 5. (Sample and hold at AT interval). Compare a with a preset comparison value and check whether the human power level is greater (a≧b).

Here, if a is not greater than the comparison value, repeat #1.

#2: If the input level a exceeds the set value S in #1, the flow moves to this step, waits for 12 hours, and detects whether the human power level a exceeds the set value S again.

#3: If it is detected in #2 that the human power level a exceeds the set value S, it is assumed that the condition (a≧b) is T2 or higher, and the control that connects to the recording/recording device 4 is performed. Set signal e to H level. (It is determined that an audio signal has been generated) #4: Next, it is detected again whether or not the human power level a exceeds the set value A, and as long as the exceeded state (a≧b) continues, the flow continues with #4. The control signal e is kept at the H level because of the repetition.

#5: When the human power level becomes less than the set value in #4, wait for the set time T3 and check again whether the human power level is less than the set value.

Here, if the human power level a exceeds the set value,
Since the flow returns to #4, the control signal e remains at H level,
The recording/recording device 4 continues recording intermittently.

#6: When the flow reaches this step, it is assumed that the input level a is below the set value and T3 or higher, and is connected to the recording/recording device.The control signal e is set to L level and recording is interrupted, and the flow continues. Return to #1 and continue the detection operation one more time.

In the above explanation, the AT time is T2/100 to T2.
/10sec, T2 is 0, 1~'I SeC,
T3 is selected to be about 1 to 10 seconds.

Therefore, it is possible to prevent the control signal e from the control device 5 from being switched at high speed and in a complicated manner.

That is, according to this embodiment, as described above, when the audio level exceeds a predetermined value and the audio level remains at the predetermined value or higher for a predetermined period, the recording/recording device The recording operation is started, and once the recording state is entered, the operation of the recording/recording device is stopped only when the audio level remains below a predetermined value for a predetermined period. Even if there are small fluctuations in the level around the value, recording is always performed for a certain period of time, so stable recording can be performed.

In the above-mentioned embodiment, the control device 5 operated according to the absolute value of the input level, but next, another embodiment of the control device 5 that operates based on the fluctuation value of the human power level will be explained using FIG. 3. do.

FIG. 3 is a block diagram of the control device 5 that detects the fluctuation value in such a case.

A subtracter 7 that subtracts the output of the circuit 9 compares the output of the subtracter 6 with a predetermined value β, and outputs an H level when the output of the subtracter 6 is larger than the predetermined value β. is a counter connected to .

Next, the operation of the embodiment configured as described above will be explained. By detecting the difference between the audio level delayed by a predetermined time AT and the undelayed audio level by the subtracter 6 and the delay circuit 9, stationary noise components are removed, and a signal corresponding to the variation in the audio level is detected. Ru. A comparator 7 in the latter stage compares a signal corresponding to the variation with a predetermined value β, and when the variation exceeds the predetermined value β, the comparator 7 changes the signal from the variable to the H level. will start and recording will start.

Next, the counter 8 counts the CLOCK signal, and when it reaches a predetermined value and the signal falls to the H level, recording stops.

Furthermore, when the audio level fluctuates sharply, the counter 8 is reset each time a high level signal is output from the comparator 7 according to the fluctuation, so that the output of the counter 8 becomes high level. Since the current status remains the same, recording is performed intermittently.

Therefore, according to this embodiment, since recording is performed according to the fluctuation of the audio level, it is possible to perform recording even in an environment where there is a lot of constant noise compared to the case where recording is performed based on the absolute value of the audio level. It can be used. Furthermore, in this embodiment, recording is intermittent for a certain period of time up to the embodiment shown in FIG.

In the above description of the embodiment, the start and stop of the operation of the recording/recording device 4 was controlled based on the level of the audio signal.
The start and stop of the operation of the recording/recording device may be controlled based on the output of the light receiving circuit 1 that detects the brightness within the imaging range of the imaging device 3 shown in FIG.

In that case, the flowchart shown in FIG. 2 and the circuit shown in FIG. 3 can be used in the same way.

In addition, in this embodiment, the audio and video were recorded in synchronization, but if the audio level exceeds a predetermined value or if the variation in the audio level exceeds a predetermined value, the audio recording and light receiving circuits If the output exceeds a predetermined value or the variation of the output exceeds a predetermined value, recording may be performed separately such as image recording.

In the embodiment described above, only one set of the audio level detection circuit 2 and the control device 5 is provided, but it is possible to provide a plurality of audio level detection circuits and set the range detected by the detection circuit to a plurality of different ranges. In this case, the imaging range of the imaging device 3 can be changed based on the detection result of the audio signal.

As mentioned above, by simply adding a control mechanism that detects the level of audio signals and changes in the amount of light received and determines the recording timing to conventional imaging devices and recording devices for monitoring and recording, it is possible to It is possible to automatically record the audio when the audio is input manually or the video and audio when a visual change occurs.

As a result, only the necessary and sufficient information is recorded for monitoring and recording purposes, and the information capacity of the recording medium used for long-term monitoring and recording is relatively small.
Later searches will also be easier.

In order to fully demonstrate the above effects, the recording device of this embodiment is specifically used for long-term monitoring in areas that are usually unmanned and where little audio signals are received, such as monitoring objects or people passing in a specific passage. checking for intruders in prohibited areas, checking for customers using unmanned service systems related to financial institutions, especially at night, observing birds and animals such as bird watching, checking for visitors when going out (for house-sitting), etc. Conceivable.

<Effects of the Invention> As explained above, according to the present invention, since video recording is performed based on a signal according to the audio level, the recording amount can be made as necessary and sufficient, and furthermore, when playing back, searching is possible. Easy to do.

[Brief explanation of drawings]

FIG. 3 is a block diagram of another embodiment. 1 is a light receiving circuit, 2 is an audio signal level detection circuit, 3 is an imaging device, 4 is an audio recording device, and 5 is a control device.

Claims (2)

[Claims] (1) It is characterized by comprising an audio level detection means for detecting an audio level and outputting a signal according to the level, and a recording means for starting or stopping video recording in response to the signal from the detection means. recording device. (2) The recording means is a means for converting the subject image into an electrical signal and recording based on the electrical signal, and the audio level detection means is a means for detecting the audio level of the subject image. A recording device according to claim 1.