KR0162335B1 - Method & apparatus for controlling sound focus for a camcorder - Google Patents

Abstract

The present invention relates to a voice focus control apparatus and method of a camcorder, which focuses on a specific sound when recording a micro audio signal so that only the voice of a person whose surrounding noise is removed is recorded, and the subject is zoomed. It is designed to automatically adjust the amplification intensity only for a specific voice signal, not all voice signals in conjunction with zoom in / out at in / out.

The present invention as described above comprises analog / digital conversion means for digitally processing a voice signal obtained from a voice transmission medium; A band conversion specific sound for selecting and amplifying a predetermined band through the first path according to the level of the digital signal obtained by the analog / digital converting means, and filtering the predetermined band through the second path to output the mixed signals of the two paths. Selection means; And switching means for selecting and outputting the output signal of the analog / digital conversion means and the band conversion specific sound selection means according to the mode from the key input means.

Description

Voice focus control device and method of camcorder

1 is a block diagram of an audio focusing apparatus of a conventional camcorder.

2 is a frequency analysis diagram in the normal mode and the wind mode of FIG.

3 is a block diagram of the audio focus control apparatus of the camcorder of the present invention.

4 is a block diagram showing in more detail the band conversion specific sound selection means of FIG.

5 is an output waveform diagram of each part of FIG.

(a) is an actual analog audio signal waveform diagram amplified by the first amplifier,

(b) is an output waveform diagram of a digitalized Fourier transform unit,

(c) is an output waveform diagram of the first variable band filter unit,

(d) is a waveform diagram obtained by amplifying the output signal of the first variable band filter unit by the second amplifier unit.

6 is a configuration diagram of another embodiment of the audio focus control apparatus of the camcorder according to FIG.

* Explanation of symbols for main parts of the drawings

200: microphone 201: first amplifier

202: analog / digital conversion unit 203: band conversion specific sound selection means

203a: Fourier transform unit 203b: Level detector

203c: Microprocessor 203d: First Variable Band Filter

203e: second amplifier 203f: second variable band filter

204: digital signal processor 205: digital / analog converter

The present invention relates to voice focus control of a camera integrated V-Cal (hereinafter, referred to as a camcorder), and more particularly, when recording a voice along with an image of a subject in a sea or other places where wind and ambient noise are high. Like the image focus, an audio signal relates to an audio focus control apparatus and method of a camcorder for focusing on a specific sound to be recorded.

Voice focusing apparatus of the conventional camcorder, as shown in Figure 1 attached to, a microphone 100 for converting the user's voice into an electrical signal; A buffer unit 101 for buffering and outputting an electric voice signal input from the microphone 100; A high pass filter 102 which blocks low frequencies from the electric voice signal of the microphone 100 and extracts only high levels of a predetermined level; Switching is switched according to the wind mode and the normal mode to select the audio signal buffered by the buffer unit 101 in the normal mode, and the high pass filtered by the high pass filter 102 in the wind mode. A voice selection switch 103 for selecting and outputting a voice signal of the component; The amplification unit 104 amplifies a voice signal selected and output by the voice selection switch 103 and outputs the same through an output terminal 105.

The voice focusing apparatus of the conventional camcorder configured as described above will be described with reference to FIG.

First, when a voice is input to the microphone 100 when the audio is to be recorded together with an image of a subject in a sea or other places where the wind and the surrounding noise are severe, the microphone 100 converts the input voice into an electrical voice signal. The conversion is input to the buffer unit 101 and the high pass filter unit 102.

The buffer unit 101 buffers the input voice signal and supplies it to the fixed terminal (a) of the voice selection switch 103. The high pass filter unit 102 has a low range among the voice signals input from the microphone 100. After removing, only the high range is extracted and supplied to the fixed terminal (b) of the voice selection switch (103).

That is, as shown in FIG. 2, the high pass filter 102 blocks the low range by setting the level to fall to -3 kHz from 200 kHz of the audible frequency.

At this time, when the user selects the normal mode, the movable terminal (c) of the voice selection switch 103 is switched to its fixed terminal (a) to receive the voice signal buffered by the buffer unit 101, that is, the second signal. As shown in the solid line of the figure, ambient noise including the pure audio signal existing within the range of 16 Hz to 20 Hz is input to the amplifier 104.

The amplifying unit 104 amplifies the voice signal including the noise input through the voice selection switch 103 in the normal mode and outputs the output signal to the output terminal 105 to be recorded on the tape.

In the above, if the user selects the wind mode, the movable terminal (c) of the voice selection switch 103 is switched to its fixed terminal (b) side as opposed to the normal mode, so that the high frequency filter unit 102 Only the high range of the low-frequency removed audio signal is amplified by the amplifying unit 104, and the tape is recorded on the tape through the output terminal 105.

However, since the conventional voice focusing apparatus of the camcorder removes the low range as an analog band pass filter at the time of the wind mode, when the important voice signal of the low pass signal is input, there is a problem that the voice noise and the ambient noise are simultaneously removed. In addition, the analog high-pass filter has a problem that the slope of the filter is not sharp to pass only a specific portion, so that other sounds are selected. Also, in the normal mode, the entire frequency band is amplified through the microphone amplifier. Noise and other noises can be introduced to create a sound that is quite annoying during playback, and when a certain number of people delivers speech in words, there is no function to detect and record only this sound. There was a problem that could not be detected.

Accordingly, an object of the present invention is to address the above-mentioned problems, and when the micro audio signal of a camcorder is recorded, the audio signal is also focused on a specific sound by using a digital filter, similar to the image focus, and the surrounding noise is removed. The present invention provides a voice focus control apparatus of a camcorder for reproducing only voice of a camera.

It is another object of the present invention to vary the selection band frequency according to the voice signal of the object currently being photographed so that the important voice signal of the low pass signal is also recorded.

Still another object of the present invention is to automatically adjust amplification intensity only for a specific audio signal, not all audio signals, in conjunction with zoom in / out when zooming in on a subject.

A voice focus control apparatus of a camcorder for achieving the object of the present invention comprises: analog / digital conversion means for sampling and digitally processing a voice signal obtained by amplifying from a voice transmission medium; When the wind mode is selected from the key input means, the frequency band is varied according to the level of the digital signal obtained by the analog / digital converting means, and the sound of the two paths is removed and passed through. Band conversion specific sound selection means for selectively outputting the digital sound of the time analog / digital conversion means; Digital signal processing means for digitally processing a voice signal obtained by the band conversion specific sound selection means and reproducing it through an audio head; And digital / analog converting means for converting the digitally processed voice signal into an analog signal and outputting the same to a speaker.

The band conversion specific sound selection means comprises: Fourier transform means for converting the time function of the digital signal of the analog / digital conversion means into a function of frequency; Level detecting means for detecting a level of a frequency generated by said Fourier changing means; A microprocessor for generating a frequency band variable control signal and a switching control signal in accordance with the level obtained by the level detecting means and the wind mode and the normal mode of the key input means; First variable band filter means for changing a frequency band according to a frequency band variable control signal obtained by the microprocessor to pass only a frequency of a predetermined band from a frequency obtained by a level detecting means; Second variable band filter means for changing a frequency band according to a frequency band variable control signal obtained by the microprocessor to remove only a predetermined band from the digital signal of the analog / digital conversion means; Mixing means for mixing the two bands obtained by the first and second variable band filter means by mixing frequencies; And an audio selection switching means for selecting the digital audio signal of the analog / digital conversion means or the audio signal of the mixing means and providing the digital signal processing means to the digital signal processing means by the switching control signal obtained by the microprocessor.

Hereinafter, described in detail with reference to the accompanying drawings of the present invention.

3 is a configuration diagram of a voice focus control apparatus of a camcorder of the present invention, and a microphone 200 which is a voice transmission medium for converting audio sound of an object into an electrical signal when photographing a subject as shown in the drawing; A first amplifier 201 for amplifying and outputting an electrical audio signal input from the microphone 200 to a predetermined level; An analog / digital converter (202) for sampling and digitally processing the audio signal amplified by the first amplifier (201); A key input unit 206 for selecting and setting the wind mode and the normal mode according to the photographing conditions; When the wind mode is selected from the key input unit 206, the frequency band is varied according to the level of the digital audio signal input from the analog / digital conversion unit 202, thereby removing and passing only the frequency sound of a predetermined band. Band conversion specific sound selection means (203) for outputting the mixed sound of the path and selecting and outputting the digital sound of the analog / digital conversion unit (202) when the normal mode is selected; A digital signal processing unit 204 for processing the audio signal selected by the band conversion specific sound selection means 203 into a digital signal and recording it on a tape through an output terminal 207 and an audio head (not shown); A digital / analog converter 205 converts the digital voice signal processed by the digital signal processor 204 into an analog signal and outputs the analog voice signal to a speaker (not shown) through the output terminal 208.

As shown in FIG. 4, the band conversion specific sound selection means 203 converts the time function of the digital signal converted and input from the analog / digital conversion unit 202 into a function of frequency and outputs a Fourier. A conversion unit 203a; A level detector (203b) for detecting and branching the level of the frequency with respect to the time function generated by the Fourier change unit (203a); A microprocessor (203c) for generating a frequency band variable control signal and a switching control signal according to the level of the frequency detected by the level detector (203b) when the wind mode is selected by the key input unit (206); In the wind mode, the frequency band is changed by a frequency band variable control signal generated and input by the microprocessor 203c to filter and output only a frequency of a predetermined band at a frequency level branched from the level detector 203b. One variable band filter 203d; A second variable band filter unit for changing a frequency band by a variable frequency band control signal obtained by the microprocessor to remove only a predetermined band from the digital signal input from the analog / digital converter 202 and to output another frequency band (203f); A second amplifier 203e for amplifying and outputting a frequency of a predetermined band input by being filtered by the first variable band filter 203d to a predetermined level; A mixing unit 203g for mixing and outputting a frequency of a predetermined band amplified by the second amplifying unit 203e and a frequency other than a predetermined band filtered by the second variable band filter unit 203f and outputting the mixed frequency; The digital audio signal of the analog / digital converting unit 202 or the audio signal of the mixing unit 203g is converted into the switching control signal of the microprocessor 203c according to the wind mode or the normal mode selection from the key input unit 206. An audio selection switching unit 203h, which is selected and provided to the digital signal processing unit 204, is constituted.

When described in detail with reference to Figure 3 to Figure 5 the effect of the present invention configured as described above.

First, when an audio signal is input through the microphone 200, which is a voice transmission medium, when the audio is to be recorded together with the image of the projectile at a beach or other places where the wind and the surrounding noise are severe, the first amplifier 201 may be used. The pure audio signal input through the microphone 200 is amplified to a predetermined level with respect to the time t as shown in FIG. 5 (a) and input to the analog / digital converter 202.

The analog / digital conversion unit 202 converts the audio signal input from the first amplifier 201 into a digital signal and fixes the fixed terminal of the audio selection switching unit 203h configured in the band conversion specific sound selection unit 203. a) and the Fourier transform unit 203a and the second variable band filter unit 203f.

The Fourier transform unit 203a of the band conversion specific sound selection unit 203 converts the digital audio signal for the time function inputted from the analog / digital converter 202 to the frequency as shown in FIG. The function is converted into a function and input to the level detector 203b.

As shown in (b) of FIG. 5, the level detection unit 203b extracts a frequency having the largest level from the signal of the frequency band input by Fourier transform and inputs it to the first variable band filter unit 203d and the microprocessor 203c. Done.

At this time, when the photographer (user) selects the wind mode through the key input unit 206, the microprocessor 203c changes the frequency band according to the level of the frequency input from the level detector 203b. The frequency band variable control signal is supplied to the first and second variable band filter units 203d and 203f, respectively, and a switching control signal is generated to move the movable terminal c of the audio selection switching unit 203h to its fixed terminal. Switch to (b) side.

The first variable band filter unit 203d selectively changes the frequency band according to a frequency band variable control signal input from the microprocessor 203c, and the frequency variable input from the level detection unit 203b is set as shown in FIG. As in c), only the frequency band of the largest level is passed through to the second amplifier 203e, and the other frequency bands are removed.

The second amplifier 203e amplifies the frequency band filtered from the first variable band filter unit 203d to a predetermined level, that is, 0 Hz or more as shown in FIG. ).

On the other hand, the second variable band filter unit 203f of the band conversion specific sound selection means 203 selectively varies the frequency band by the frequency band variable control signal input from the microprocessor 203c to perform the analog / digital digital signal. Of the digital audio signals input from the converter 202, the predetermined frequency band is cut off and only the other frequency band is passed to the mixer 203g.

That is, unlike the first variable band filter unit 203d, the second variable band filter unit 203f blocks the largest frequency band among the frequency bands input from the analog / digital converter 202 and only the other frequency bands. It passes through and enters into the mixing part 203g.

The mixing unit 203g is an audio signal of a frequency band other than that in which a predetermined band is blocked by the second variable band filter unit 203f, and the audio of the frequency band having the highest level amplified and input by the second amplifier 203e. The signals are mixed and input to the fixed terminal b of the audio selection switching unit 203h.

At this time, since the movable terminal c of the audio selection switching unit 203h is connected to its fixed terminal b by the switching control signal of the microprocessor 203c according to the wind mode, the mixing unit 203g The mixed audio signal is input to the digital signal processing unit 204 through the audio selection switching unit 203h.

The digital signal processing unit 204 processes the input digital audio signal and records the digital audio signal at the audio track end of the video tape without noise through the output terminal 207 and the audio head, and digitally / analog converting the digital signal. (205).

On the other hand, when the photographer selects the normal mode through the key input unit 206, the microprocessor 203c outputs a switching control signal to convert the movable terminal c of the audio selection switching unit 203h to its fixed terminal. The connection is switched to (a).

Accordingly, in the normal mode, the digital audio signal converted by the analog / digital converter 202 is input to the digital signal processor 204 through the audio selection switch 203h.

As described above, the digital signal processing unit 204 processes the input digital audio signal, records the digital audio signal at the audio track end of the videotape through the output terminal 207 and the audio head, and digitally processes the digital signal. It is input to the analog converter 205.

The digital / analog converter 205 converts the input digital audio signal into an analog audio signal and reproduces the output through the output terminal 208.

6 is a configuration diagram of another embodiment of the audio focus control apparatus of the camcorder according to FIGS. 3 and 4, wherein the zoom in / out is performed when zooming in and out. In conjunction with this, the gain of the specific signal is automatically adjusted through the second amplifying unit 203e of the band conversion specific sound selection means 203 so as to reproduce without noise.

That is, a zoom in / out key input unit 209 for selecting and inputting a zoom in / out; A zoom lens position detector 211 which detects a movement position of the zoom lens according to the key signal of the zoom in / out key input unit 209; A microprocessor (203c) for determining a zoom-in / out key signal and a zoom value of the zoom lens inputted from the zoom-in / out key input unit 209 and the zoom lens position detection unit 211 and outputting them with different voltage levels; It is composed of an electronic volume 210 that adjusts the gain of the second amplifier 203c by varying the voltage level output from the microprocessor 203c, and the same parts as those of FIGS. 3 and 4 are the same. The code is given and the detailed operation thereof is omitted.

First, when the zoom in / out key is selected and input from the zoom in / out key input unit 209 in FIG. 6 and the position of the current zoom lens from the zoom lens detection unit 211 is detected and input, the microprocessor ( 203c determines the zoom in or out and the position of the current zoom lens, and inputs the electronic volume 210 by varying the DC level according to the determined result.

The electronic volume 210 is input as a gain control signal of the second amplifier 203e of the band conversion specific sound selection means 203 by varying the DC voltage according to the DC level input from the microprocessor 203c.

The second amplifier 203e changes the gain step by step according to the gain control signal generated from the electron volume 210, that is, the variable DC voltage, respectively, from the first variable band filter unit 203d. An audio signal of a predetermined frequency band to be input is amplified by the changed gain and input to the mixing unit 203g.

The mixing unit 203g mixes an audio signal input by gain adjustment for a predetermined band from the second amplifier 203e and an audio signal other than a predetermined frequency band input from the second variable band filter unit 203f. The digital signal processing unit 204 is provided to the above-described digital signal processing unit 204 via the audio selection switching unit 203h to record and reproduce the audio track at the end of the videotape. On the other hand, in the present invention, the voice level is automatically reduced and increased when zooming in and out only for a specific voice signal.

As described in detail above, according to the present invention, when the micro audio signal of the camcorder is recorded, the audio signal is also focused on a specific sound by using a digital band filter, similar to the image focus. In addition to recording, by changing the selected band frequency according to the voice signal of the object being recorded, it is also possible to record the important voice signal of the low range signal and also to zoom in / out when zooming in and out when shooting a subject. The amplification intensity can be automatically adjusted only for a specific voice signal, not a voice signal.

Claims (7)

Analog / digital conversion means for digitally converting a voice signal obtained by amplification from a voice transmission medium; A band conversion specific sound for selecting and amplifying a predetermined band through the first path according to the level of the digital signal obtained by the analog / digital converting means, and filtering the predetermined band through the second path to output the mixed signals of the two paths. Selection means; And a switching means for selecting and outputting an output signal of the analog / digital conversion means and the band conversion specific sound selection means according to the mode from the key input means. 2. The apparatus according to claim 1, wherein the band conversion specific sound selection means comprises: level detection means for detecting a frequency level of the digital signal of the analog / digital conversion means; A microprocessor which generates a frequency band variable control signal and a switching control signal in accordance with the level obtained by the level detecting means and the mode of the key input means; First variable band filter means for filtering and outputting a frequency of a predetermined band detected by the level detecting means; Amplifying means for amplifying the output signal of the first variable band filter means; Second variable band filter means for filtering and outputting a digital signal of the analog / digital conversion means; And a mixing means for mixing and outputting the output signal of the amplifying means and the second variable band filter means. 3. The apparatus according to claim 2, wherein the first variable band filter means is configured to pass only a frequency band having the largest frequency level obtained by the level detection means. The apparatus of claim 2, wherein the second variable band filter means is configured to pass only the frequency band other than the largest frequency level by the variable frequency band control signal of the microprocessor. 3. The apparatus according to claim 2, wherein the frequency bands of the first and second variable band filter means are configured to vary according to the level of the input audio signal. 3. The apparatus of claim 2, further comprising: zoom in / out key input means for providing a zoom in / out key signal to the microprocessor; Zoom lens position detecting means for detecting a position of the zoom lens; The electronic device is configured to vary the voltage level according to the control signal of the microprocessor according to the zoom in / out key selection and the position value of the zoom lens position detection means, and to adjust the gain of the amplification means using the variable value to control the audio signal of the predetermined band. Voice focus control apparatus of the camcorder, characterized in that further comprises a volume. A first step of converting a voice signal obtained by amplification from a voice transmission medium into a digital signal, and processing the digital signal immediately in a normal mode and determining a band having a large frequency level of the digital signal in a wind mode, And a second step of amplifying by passing only a predetermined band in one path and removing the predetermined band in the other path to output the mixed signals of the two paths.