JP2012044341A - Audio processing apparatus and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drive sounds resulting from lens drive from mixing with ambient sounds to be captured to degrade sound quality.SOLUTION: A zoom drive section (108) has a plurality of drive modes causing different drive sounds. A zoom data storage section (105) stores data 1, 2 indicating criteria of whether or not ambient sounds mask the drive sounds in the plurality of respective drive modes. A spectral transformation section (104) spectral-transforms an audio signal input by a microphone (101), and a storage section (110) stores output data from the spectral transformation section (104). A comparison section (106) compares the spectral data in the storage section (110) with the criteria in the zoom data storage section (105). A zoom drive control section (107) actuates the zoom drive section (108) in the drive mode depending on the result of comparison by the comparison section (106).

Description

  The present invention relates to an audio processing device and an imaging device, and more particularly to an audio processing device and an imaging device that reduce the entry of drive sound into ambient sounds to be captured.

JP 2003-233947 A JP 2005-176015 A

  Conventionally, digital cameras and video cameras are provided with a lens driving mechanism for autofocus or optical zoom. When the lens driving mechanism is operated during shooting or recording, a driving sound is generated, and this driving sound is recorded as noise in the conventional imaging apparatus.

  Patent Document 1 describes a configuration in which a filter that reduces driving sound generated by a driving mechanism is connected to an output of a microphone that captures external sound, and the filter is controlled in accordance with the operating state of the driving mechanism. Drive noise generated when the drive mechanism is driven is reduced by a filter, and S / N is improved when the environmental sound outside the device is signal S (Signl) and the drive sound of the drive mechanism is noise N (Noise).

  Patent Document 2 describes a configuration in which an imaging lens is driven at a normal speed when the surrounding sound pressure is high and is driven at a lower speed when the sound pressure is low in an imaging apparatus including a zoom mechanism. Are listed.

  In the prior art described in Patent Document 1, the filter is validated during the operation of the drive unit regardless of the level of the ambient sound. For example, even when the ambient sound is so loud as to mask the drive noise generated when the drive mechanism is operated, the filter is caused to function, thereby deteriorating the frequency characteristics of the recorded sound.

  In the prior art described in Patent Document 2, the sound pressure of ambient sound is detected, and a normal mode in which the imaging lens is driven at a normal speed and a silent mode in which the imaging lens is driven at a low speed are switched. However, when the frequency of the driving noise is far from the frequency band in which the ambient sound exists, even in the silent mode, the sound that makes the driving sound very conspicuous is recorded in terms of hearing.

  It is an object of the present invention to present a voice processing device and an imaging device that can eliminate such inconvenience.

  In order to achieve the above object, an audio processing apparatus according to the present invention stores driving means capable of operating in a plurality of driving modes that generate different driving sounds, and determination reference values for each of the plurality of driving modes. Storage means, voice acquisition means for acquiring ambient voice and outputting a voice signal, comparison means for comparing the voice signal from the voice acquisition means and the determination reference value stored in the storage means And control means for controlling the drive mode of the drive means according to the comparison result of the comparison means.

  An imaging device according to the present invention includes the above-described audio processing device.

  According to the present invention, a driving mode with a maximum driving sound or a high-speed driving mode is selected from among a plurality of driving modes within a range masked by the surrounding sound volume, so that the driving sound is prevented from entering the surrounding sound. However, high driving ability can be used.

It is a schematic block diagram of the characteristic part of one Example of this invention. It is a schematic block diagram of one Example of this invention. It is a flowchart figure of the basic operation | movement of a present Example. It is an example of the spectrum of the drive sound for every drive mode. It is an operation | movement flowchart of the drive mode control of a present Example. It is a comparative example of a spectrum. It is the example of a change of FIG. An example of a pass band of a band pass filter in the spectrum conversion unit is shown. It is an operation | movement flowchart of a structure shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 shows a schematic block diagram of an imaging apparatus incorporating an embodiment of a sound processing apparatus according to the present invention, and FIG. 1 shows a schematic block diagram of its characteristic part. FIG. 3 shows an operation flowchart of this embodiment.

  The configuration and basic operation of the embodiment shown in FIG. 2 will be described. A lens 201 forms an optical image in which an optical image of a subject is incident on the image sensor 203. An optical system mechanism unit 202 includes an optical zoom mechanism that enlarges and reduces a subject optical image incident on the image sensor 203, an aperture mechanism that controls the amount of light, and a shutter mechanism that blocks light during shooting. The image sensor 203 is an element that converts subject light imaged by the lens 201 into an electric signal, and includes a CCD type or a CMOS type.

  Reference numeral 204 denotes an imaging signal processing unit that performs imaging signal processing such as correlated double sampling processing for removing clocks and reducing noise from the output electrical signal of the imaging device 203 and clamping processing for clamping to a predetermined reference voltage. Reference numeral 205 denotes a / D conversion unit that converts an analog signal output from the imaging signal processing unit 204 into a digital signal. An image signal processing unit 206 converts the output digital data of the / D conversion unit 205 into a predetermined display format and recording format.

  An optical system control unit 207 drives the optical system mechanism unit 202. A system control unit 208 controls the entire digital camera and performs various calculations. The system control unit 208 includes, for example, a CPU and memory, or a microprocessor. Reference numeral 209 denotes a recording medium such as a semiconductor memory in which image data and audio data can be written and read.

  A power supply unit 210 supplies power to all blocks of the digital camera. An operation unit 211 instructs the system control unit to turn on / on the digital camera, select a mode, release, zoom, and the like.

  An audio input unit 212 performs processing so that ambient audio can be converted into electrical signals and recorded as digital data. An audio output unit 213 reproduces and outputs recorded audio.

  An image display processing unit 214 processes display data sent from the system control unit 208 so that the display data can be output to a video monitor such as an LCD (liquid crystal display device) or a TV receiver. A D / A conversion unit 215 converts a digital signal from the image display processing unit 214 into an analog signal. An image display unit 216 displays the image data output from the D / A conversion unit 215 as an image. An image display unit 216 LCD is provided.

  Although not shown, an image output terminal for outputting image data to an external TV receiver or the like is provided. When TV output is selected as the display mode, the system control unit 208 outputs image data from the image output terminal instead of the image display unit 216 or simultaneously with the image display unit 216.

  The basic operation of the present embodiment will be described with reference to FIG. When the main switch of the operation unit 211 is turned on (S301), the power source unit 210 starts operation and supplies main power and control system power. The system control unit 208 determines whether the mode is the shooting mode or the playback mode (S302), and enters the shooting sequence in the shooting mode, and enters the playback sequence in the playback mode.

  In the reproduction sequence, the system control unit 208 reads image data from the recording medium 209 (S318), and the image display processing unit 214 performs signal processing for image display. When LCD is designated as the display mode (S319), the system control unit 208 turns on the LCD display (for example, supplies power to the LCD) (S320), and in the case of TV output (S319), external The image data is output to (S321). The system control unit 208 maintains the image display state until the main switch of the operation unit 211 is turned off (S322). When the main switch is turned off (S322), the system control unit 208 stops displaying the image and turns off the power. .

  In the shooting sequence, the system control unit 208 drives the lens 201 (S303), turns on the power of imaging system circuits such as the imaging device 203 and the imaging signal processing unit 204, and drives in the live image mode (S304). The system control unit 208 controls the optical system control unit 207 to open the aperture / shutter of the optical system mechanism unit 202 (S305) and enter an AF (autofocus) sequence.

  The output image signal of the imaging element 203 is processed as described above by the imaging signal processing unit 204, the A / D conversion unit 205, and the image signal processing unit 206, and is input to the system control unit 208. The system control unit 208 calculates the AF control value by comparing the image data from the image signal processing unit 206 in time series (S306). Using this calculation result, the system control unit 208 controls the exposure amount, that is, the diaphragm and shutter of the optical system mechanism unit 202 (S307).

  The system control unit 208 checks the display mode (S308), and outputs it to the LCD if it is an LCD (S309), and outputs image data to the outside if it is a TV output (S310).

  The system control unit 208 confirms whether the mode selection switch of the operation unit 211 is a still image mode or a moving image mode (S311). When the moving image mode is selected (S311), the system control unit 208 waits for the shooting switch of the operation unit 211 to be turned on (S312). When the shooting switch is turned on (S312), the system control unit 208 changes the imaging system circuit to the operation in the moving image shooting mode, and turns on the power of the audio input unit 212 (S313). The imaging system circuit includes an imaging element 203, an imaging signal processing unit 204, an A / D conversion unit 205, and an image signal processing unit 206. The system control unit 208 processes the image signal from the image signal processing unit 206 and the input audio signal from the audio input unit 212 for recording and records them in the recording medium 209 (S314).

  When the user turns on the photographing switch again (S315), the system control unit 208 ends recording on the recording medium 209, changes the imaging system circuit to the live image mode, and turns off the power of the audio input unit 212 ( S316). If the main switch is on (S317), the system control unit 208 returns to S302. When the main switch is off (S317), the system control unit 208 ends the shooting mode process. That is, the power supply of the imaging system circuit is turned off, the optical system mechanism unit 202 is returned to a predetermined position, and the main power supply is turned off.

  When the still image mode is selected (S311), the system control unit 208 waits for the photographing switch of the operation unit 211 to be turned on (S323). When the user turns on the shooting switch (S323), the system control unit 208 changes the imaging system circuit to the still image shooting mode (S324). The system control unit 208 executes still image shooting and records the shot image data on the recording medium 209 (S325). After completing the recording process of the photographed still image, the system control unit 208 changes the imaging system circuit to the live image mode (S326). If the main switch is on (S327), the system control unit 208 returns to S302. When the main switch is off (S327), the system control unit 208 ends the shooting mode process. That is, the power supply of the imaging system circuit is turned off, the optical system mechanism unit 202 is returned to a predetermined position, and the main power supply is turned off.

  FIG. 1 shows a schematic block diagram of a component that controls the drive sound of the optical system drive unit according to the sound pressure or volume of ambient sound, which is a characteristic part of the present embodiment. Here, the zoom drive unit 108 is illustrated as the optical system mechanism unit 202, and the zoom drive control unit 107 is illustrated as the optical system control unit 207.

  Reference numeral 101 denotes a microphone that captures sound as an electrical signal as sound acquisition means. Reference numeral 102 denotes a microphone amplifier for amplifying a minute electric signal output from the microphone 101. Reference numeral 103 denotes an A / D converter that converts the amplified analog audio signal output from the microphone amplifier 102 into a digital signal. Reference numeral 104 denotes a spectrum conversion unit that Fourier-transforms data output from the A / D conversion unit 103 and outputs spectrum data indicating a level for each frequency.

  A zoom drive control unit 107 controls the zoom drive unit 108. The zoom drive unit 108 drives the zooming lens of the lens 201 in the optical axis direction according to a control signal from the zoom drive control unit 107. The zoom drive control unit 107 has a plurality of drive modes for zoom drive. For example, when the zoom drive unit 108 is configured by a DC motor, the drive frequency can be selected. When the zoom driving unit 108 is configured by a stepping motor, one-phase excitation, two-phase excitation, 1 and 2-phase excitation, microstep driving, and the like can be selected.

  Reference numeral 105 denotes a zoom data storage unit that stores spectral data in which the sound level during operation of the zoom drive unit 108 is greater than a predetermined level in a quiet environment by a predetermined level or more. The data stored in the zoom data storage unit 105 is a determination reference value serving as a reference for determining whether or not the drive sound generated by the zoom drive unit 108 (optical system mechanism unit 202) can be masked by the surrounding sound volume. Indicates. In the following description, an environment where the recording level is equal to or lower than a predetermined level and the recording level fluctuation is equal to or lower than a predetermined value is referred to as a silent environment. Data stored in the zoom data storage unit 105 is prepared for each of a plurality of drive modes of the zoom drive control unit 107. Reference numeral 110 denotes a storage unit that holds audio spectrum data output from the spectrum conversion unit 104. A comparison unit 106 compares the spectrum data stored in the storage unit 110 with the spectrum data of each drive mode stored in the zoom data storage unit 105.

  An audio processing unit 109 performs audio processing such as frequency filter and audio level control on the audio data output from the A / D conversion unit 103.

  An example of spectral data stored in the zoom data storage unit 105 will be described with reference to the spectral waveform example shown in FIG.

  Assuming that the motor of the zoom drive unit 108 is a DC motor, a case where there are two types of drive frequencies of 100 Hz drive and 200 Hz drive as the zoom drive mode will be described. FIG. 4A shows an example of spectrum data when zoom driving is performed at 100 Hz in a quiet environment. FIG. 4B shows an example of spectrum data when zoom driving is performed at 200 Hz in a quiet environment. In the frequency region 401 of FIG. 4A, it is assumed that the sound level during operation of the zoom drive unit 108 is higher than a predetermined level by a level higher than that during non-operation. In the frequency region 402 of FIG. 4B, it is assumed that the sound level during the operation of the zoom drive unit 108 is greater than a predetermined level than that during non-operation.

  In the zoom data storage unit 105, spectrum data illustrated in FIGS. 4A and 4B is stored in advance. A driving mode in which the zoom driving unit 108 is operated at 100 Hz driving is referred to as speed 1, and a driving mode in which the zoom driving unit 108 is operated at 200 Hz driving is referred to as speed 2. The zoom data storage unit 105 stores data 1 that is spectral data of speed 1 and data 2 that is spectral data of speed 2. Further, the data output from the spectrum conversion unit 104 when the zoom drive unit 108 is operated in an environment where the output value of the spectrum conversion unit 104 is smaller than a predetermined level except in the recording mode is stored in the zoom data storage unit 105. May be.

  FIG. 5 shows a flowchart of the characteristic operation of this embodiment. The characteristic operation of the present embodiment will be described with reference to FIGS. Recording is started (S501). The system control unit 208 monitors the operation unit 211 and waits for a zoom drive instruction (S502). When a zoom operation instruction is detected (S502), the comparison unit 106 acquires environmental sound data that is spectrum data stored in the storage unit 110. (S503). Then, the comparison unit 106 first compares the environmental sound data with the data 2 in the zoom data storage unit 105 (S504). As a result of comparison, when the environmental sound data is at a level for masking data 2 (S504), the zoom drive control unit 107 controls the zoom drive unit 108 to operate at speed 2 according to the comparison result (S505). For example, when there are n or more places where the environmental sound level is higher than the data 2 by a predetermined level or more, the zoom driving noise is erased by the environmental sound and is at a level that cannot be recognized by human hearing, that is, a level that is masked. Is determined.

  For example, it is assumed that an environmental sound spectrum 601 as illustrated in FIG. 6A is measured, and spectrum data 602 illustrated in FIG. 6B is stored as data 2 in the zoom data storage unit 105. The comparison unit 106 compares the levels for each frequency, and when the comparison result indicates that there are two or more frequencies having a predetermined value α or more and a larger environmental sound spectrum, it is determined that the level is the masking level. FIG. 6C shows the result of subtracting the spectrum data 602 from the environmental sound spectrum 601. In the difference value data 603 shown in FIG. 6C, if there are two or more sample points greater than or equal to the predetermined value α, it is determined that the level is the masking level. That is, in the example of FIG. 6, the difference between the noise level of the drive unit at a plurality of predetermined frequencies and the sound level being acquired at the plurality of predetermined frequencies are compared. Then, if there are two or more frequencies where the voice level being acquired is greater than the predetermined value α, it is determined that the level is the masking level.

  When the environmental sound data is at a level at which the data 2 cannot be masked (S504), the comparison unit 106 compares the environmental sound data with the data 1 (S506). As a result of the comparison, when the environmental sound data is at a level for masking data 1 (S506), the zoom drive control unit 107 controls the zoom drive unit 108 to operate at speed 1 according to the comparison result (S507). .

  Zooming in on an operation to shoot a large subject by zooming, and zooming out to shoot a small subject. The zoom-in and zoom-out speed at speed 1 is slower than that at speed 2. However, by using the electronic zoom processing in the image signal processing unit 206 in combination, the zoom-in / zoom-out speed experienced by the photographer can be controlled to be the same as in the case of speed 2. The electronic zoom process is a process of enlarging / reducing the image formed by the image sensor 203 by the image signal processing unit 206. In other words, assuming that speed 1 is doubled in 1 second and speed 2 is magnified 1.5 times in 1 second, the electronic zoom may be magnified 1.3 times in 1 second. .

  When the environmental sound data is at a level at which data 1 cannot be masked (S506), the comparison unit 106 notifies the system control unit 208 that masking is impossible (S508). When the system control unit 208 receives the notification that masking is impossible, the system control unit 208 controls the zoom drive control unit 107 to operate the zoom drive unit 108 at a speed 2 with a low drive noise level, and the audio signal processing unit 109 performs zoom noise reduction processing. Let it run. The zoom noise reduction process is a low-pass filter process that reduces the frequency component of noise generated in the zoom mechanism. For example, a filter process is applied to reduce the frequency components that are noticeable in noise generated at speed 2.

  Further, the system control unit 208 may prohibit the zoom driving and switch to the electronic zoom process in response to the masking impossibility notification, and display the zoom driving prohibition on the image display unit 216.

  In this embodiment, a high-speed drive mode is selected from a plurality of drive modes in a range masked by the surrounding sound volume, that is, a drive mode in which the drive sound is generally maximum. Then, the filter that removes the drive sound component from the microphone output is validated even in the slowest drive mode, that is, the drive mode that is generally the minimum drive sound, when it is not masked by the ambient sound volume. As described above, in a situation where the driving noise is masked by the ambient sound, the processing for reducing the driving noise is not performed, and thus the sound quality deterioration due to such processing can be prevented. In addition, if even the slowest drive mode (the drive mode with the lowest drive sound) is not masked by the ambient sound volume, the sound quality deterioration due to the frequency filter is enabled by enabling a frequency filter that removes the drive sound component from the captured ambient sound. The possibility of this can be reduced. If the drive sound does not depend on the zoom speed, the zoom speed masked by the acquired environmental sound data may be selected instead of the processing of FIG. 5 and S504 to S507 in this embodiment. In this case, any speed may be selected as long as it is a zoom speed at which noise is masked. Further, in this embodiment, an example in which there are two types of zoom speeds has been described, but other types of zoom speeds may be used. In the present embodiment, an example in which the spectrum conversion unit 104, the zoom data storage unit 105, the comparison unit 106, and the storage unit 110 are included in the audio input unit 212 has been described. However, all or some of these configurations may be included in the system control unit 208.

FIG. 7 shows a schematic block diagram of the main part of the second embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals.

  Assuming that the motor of the zoom drive unit 108 is a DC motor, the operation will be described by taking as an example a case where there are two types of drive frequencies of 100 Hz drive and 200 Hz drive as the zoom drive mode. It is assumed that the surrounding sound is recorded while zooming in the 100 Hz driving mode under the previously defined silent environment. It is assumed that the frequency characteristic obtained by plotting the maximum value of each frequency of the recorded data becomes the characteristic data shown in FIG. Assume that in the frequency region 401, the sound level during the operation of the zoom drive unit 108 is greater than a predetermined level than that during non-operation. Similarly, it is assumed that the frequency characteristics when operating in the 200 Hz drive mode in a silent environment are characteristic data shown in FIG. Assume that in the frequency region 402, the sound level during operation of the zoom driving unit 108 is greater than a predetermined level by a level higher than that during non-operation.

  The spectrum conversion unit 104 passes from the output data of the A / D conversion unit 103 through a bandpass filter (BPF) 701 that passes the frequency region 801 shown in FIG. 8A and the frequency region 802 shown in FIG. 8B. And a band pass filter (BPF) 702 that performs the same. The frequency domain 801 corresponds to the frequency domain 401 in FIG. 4A, and the frequency domain 802 corresponds to the frequency domain 402 in FIG. 4B. When zoom driving is performed with 100 Hz driving in a quiet environment, the maximum value of data that has passed through the BPF 701 during the driving period is stored in advance in the zoom data storage unit 105 as data 703. In addition, when zoom driving is performed at 200 Hz in a quiet environment, the maximum value of data that has passed through the BPF 702 during the driving period is stored in the zoom data storage unit 105 as data 704 in advance.

  The storage unit 110 stores moving average data 705 of data from the present passing through the BPF 701 to T seconds before the predetermined period and moving average data 706 of data from the present passing through the BPF 702 to T seconds before the predetermined period.

  FIG. 9 shows a flowchart of characteristic operations of the present embodiment. The operation of the configuration shown in FIG. 7 will be described with reference to FIG.

  Recording is started (S901). The system control unit 208 monitors the operation unit 211 and waits for a zoom drive instruction (S902). When a zoom operation instruction is detected (S902), the comparison unit 106a acquires moving average data 705 and 706 stored in the storage unit 110. (S903). First, the comparison unit 106a compares the moving average data 706 with the zoom data 704 in the zoom data storage unit 105 (S904). When the moving average data 706 is larger than the zoom data 704 by a predetermined level or more, it can be considered that the zoom driving noise is masked by the environmental sound. Therefore, as a result of comparison, when the moving average data 706 is at a level for masking the zoom data 704 (S904), the zoom drive control unit 107 controls the zoom drive unit 108 to operate at speed 2 (S905).

  When the moving average data 706 is at a level that cannot mask the zoom data 704 (S904), the comparison unit 106a compares the moving average data 705 with the zoom data 703 (S906). When the moving average data 705 is at a level for masking the zoom data 703 (S906), the zoom drive control unit 107 controls the zoom drive unit 108 to operate at speed 1 (S907).

  When the moving average data 705 is at a level at which the zoom data 703 cannot be masked (S906), the comparison unit 106a notifies the system control unit 208 that masking is not possible (9508). When the system control unit 208 receives the notification that masking is impossible, the system control unit 208 controls the zoom drive control unit 107 to operate the zoom drive unit 108 at a speed 2 with a low drive noise level, and the audio signal processing unit 109 performs zoom noise reduction processing. Let it run. The zoom noise reduction process is a low-pass filter process that reduces the frequency component of noise generated in the zoom mechanism.

  With such a configuration, in the present embodiment, in a situation where the drive noise is masked with ambient sound, the process for reducing the drive noise is not performed, so that deterioration in sound quality due to such a process can be prevented. In addition, if even the slowest drive mode (the drive mode with the lowest drive sound) is not masked by the ambient sound volume, the sound quality deterioration due to the frequency filter is enabled by enabling a frequency filter that removes the drive sound component from the captured ambient sound. The possibility of this can be reduced. In the present embodiment, an example in which the spectrum conversion unit 104, the zoom data storage unit 105, the comparison unit 106, and the storage unit 110 are included in the audio input unit 212 has been described. However, all or some of these configurations may be included in the system control unit 208.

Claims (5)

Driving means capable of operating in a plurality of driving modes each generating different driving sounds;
Storage means for storing determination reference values for each of the plurality of drive modes;
Sound acquisition means for acquiring surrounding sound and outputting sound signals;
Comparison means for comparing the audio signal from the audio acquisition means with the determination reference value stored in the storage means;
And a control means for controlling the drive mode of the drive means according to the comparison result of the comparison means.   The sound processing apparatus according to claim 1, wherein the driving unit is a unit that drives an optical system that forms an optical image incident on the image sensor. The comparison means comprises spectrum conversion means for spectrally converting the audio signal, and means for comparing the output of the spectrum conversion means with the determination reference value.
The sound processing apparatus according to claim 1, wherein the determination reference value indicates a spectrum of the driving sound.   The comparison means comprises a plurality of filter means that pass different frequency components of the audio signal, and a means for comparing outputs of the plurality of filter means with respective determination reference values of the plurality of drive modes. The speech processing apparatus according to claim 1 or 2, characterized in that:   An imaging apparatus comprising the audio processing apparatus according to claim 1.

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