JP2016009039A - Image-capturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a noise reduction process appropriately.SOLUTION: An image-capturing device has a noise cancellation unit for comparing, for each frequency, the signal level of the frequency spectrum of an inputted sound signal and the level of a noise profile, and performs level suppression. When the inputted sound level is below a predetermined threshold, a drive unit compares a signal level between the frequency spectrum before drive and the frequency spectrum whose level is suppressed by the noise cancellation unit during drive, and corrects the level of the noise profile.

Description

  The present invention relates to an imaging apparatus.

  2. Description of the Related Art Conventionally, an imaging apparatus that records an image signal and an audio signal is known. Some of these imaging devices reduce sound (driving noise, driving noise) generated by a driving unit such as a motor for moving the lens when the lens provided in or attached to the device is moved. (Patent Document 1: for example, FIG. 11).

Japanese Patent Laid-Open No. 06-349208

  The lens barrel constituting the zoom lens or the like has a level difference in driving sound during driving due to individual variations and aging. Therefore, it is necessary to correct the parameters of the sound reduction processing when driving the lens barrel in accordance with the level difference.

  The voice processing technique described above is not configured to detect the level by extracting only the driving sound of the lens barrel. That is, it is impossible to distinguish between the sound excluding the driving sound of the lens barrel and the driving sound of the lens barrel.

  Therefore, the sound level difference due to individual variation of the lens barrel and the sound level difference due to secular change cannot be detected unless the ambient sound is as low as possible, for example, in a silent environment such as an anechoic room or an anechoic box.

  Therefore, the present invention is not limited to a limited environment such as a quiet environment, but also in an environment where a certain amount of sound exists, the level difference or secular change of the driving sound at the time of driving the lens barrel due to individual variation of the lens barrel It is possible to correct a change in the level of the driving sound at the time of driving the lens barrel caused by the above, and to provide a sound signal processing device capable of correcting a frequency deviation of the driving sound at the time of driving the lens barrel in a limited environment. Objective.

  The imaging apparatus of the present invention includes an imaging unit, a driving unit that moves an optical system of the imaging unit, an FFT unit that converts time-series audio data into a frequency spectrum, and a signal level of a frequency spectrum of an input audio signal. And a noise canceling unit for suppressing the level by comparing the level of the noise profile for each frequency, an iFFT unit for returning the frequency spectrum level-suppressed by the noise canceling unit to time-series audio data, and the signal of the frequency spectrum A level comparison unit that compares a level with the level of the noise profile, and calculates a frequency shift or level shift between the noise profile and a frequency spectrum of a target drive unit, and whether to perform correction according to the result Correction determining unit for determining, and correction for calculating and correcting the correction level of the noise profile And a control means for controlling the adjusting means according to whether or not the driving section is driven, and when the input sound level is lower than a predetermined threshold, the driving section drives the frequency spectrum before driving and the driving The signal level is compared with the frequency spectrum whose level is suppressed by the noise cancellation unit, and the level of the noise profile is corrected.

  According to the present invention, not only in a limited environment such as a quiet environment, but also in an environment where a certain amount of sound exists, the level difference or secular change of the driving sound at the time of driving the lens barrel due to individual variation of the lens barrel Therefore, it is possible to correct the change in the level of the driving sound when the lens barrel is driven, and to correct the frequency deviation of the driving sound when the lens barrel is driven in a limited environment.

It is a block diagram of an imaging device. It is a block diagram which shows the detailed structure of an imaging part and an audio | voice input part. It is a figure which shows the frequency spectrum of a noise profile. It is a figure showing a noise cancellation process. It is a figure showing the frequency spectrum of a digital audio | voice signal. It is a figure showing the frequency spectrum of an audio | voice signal. It is a figure showing the frequency spectrum of an audio | voice signal. It is the figure which showed the correction parameter. It is a figure showing the frequency spectrum of a digital audio | voice signal. It is a figure showing the frequency spectrum of an audio | voice signal. It is a block diagram which shows the structure of the imaging part and audio | voice input part of a prior art example.

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

  In this embodiment, an imaging apparatus will be described with reference to FIGS. FIG. 1 is a block diagram illustrating the configuration of the imaging apparatus 100 according to the first embodiment.

  In FIG. 1, an imaging unit 101 converts an optical image of a subject captured by a photographing lens into an image signal by an imaging element, performs analog-digital conversion, image adjustment processing, and the like, and generates image data. The taking lens may be a built-in lens or a detachable lens. Further, the imaging element may be a photoelectric conversion element typified by a CCD, a CMOS or the like.

  The sound input unit 102 collects sound around the imaging apparatus 100 with a built-in microphone or connected via a sound terminal, and performs analog-digital conversion, sound processing, and the like to generate sound data. The microphone may be directional or omnidirectional, but in this embodiment, an omnidirectional microphone is used. The memory 103 temporarily stores the image data obtained by the imaging unit 101 and the audio data obtained by the audio input unit 102. The display control unit 104 displays a video related to the image data obtained by the imaging unit 101, an operation screen of the imaging device 100, a menu screen, and the like on the display unit 105 or an external display via a video terminal (not shown). .

  The encoding processing unit 106 reads out image data and audio data temporarily stored in the memory 103, performs predetermined encoding, and generates compressed image data, compressed audio data, and the like. Further, the audio data may not be compressed. The compressed image data is, for example, MPEG2 or H.264. It may be compressed by any compression method such as H.264 / MPEG4-AVC. The compressed audio data may also be compressed by a compression method such as AC3, AAC, ATRAC, ADPCM.

  The recording / reproducing unit 107 records the compressed image data, compressed audio data or audio data, and various data generated by the encoding processing unit 106 on the recording medium 108, and reads out from the recording medium 108. Here, the recording medium 108 includes all types of recording media such as a magnetic disk, an optical disk, and a semiconductor memory as long as image data, audio data, and the like can be recorded.

  The control unit 109 can control each block of the imaging apparatus 100 by transmitting a control signal to each block of the imaging apparatus 100, and includes a CPU, a memory, and the like for performing various controls. The memory used by the control unit 109 is a ROM for storing various control programs, a RAM for arithmetic processing, and the like, and includes a memory external to the control unit 109. The operation unit 110 includes buttons, a dial, and the like, and transmits an instruction signal to the control unit 109 according to a user operation.

  In the image pickup apparatus of the present embodiment, a shooting button for instructing start and end of moving image recording, a zoom lever for instructing optically and electronically enlarging and reducing an image, a cross key for performing various adjustments, and a determination It consists of keys. The audio output unit 111 outputs the audio data and compressed audio data reproduced by the recording / reproducing unit 107 or the audio data output by the control unit 109 to the speaker 112 and the audio terminal. The external output unit 113 outputs the compressed video data, compressed audio data, audio data, and the like reproduced by the recording / reproducing unit 107 to an external device. The data bus 114 supplies various data such as audio data and image data and various control signals to each block of the imaging apparatus 100.

  Here, the normal operation of the imaging apparatus 100 of the present embodiment will be described. The imaging apparatus 100 according to the present embodiment supplies power to each block of the imaging apparatus from a power supply unit (not illustrated) in response to an instruction to turn on the power by operating the operation unit 110 by the user. .

  When the power is supplied, the control unit 109 confirms which mode the mode change switch of the operation unit 110 is in, for example, a shooting mode, a reproduction mode, or the like by an instruction signal from the operation unit 110. In the moving image recording mode, the image data obtained by the imaging unit 101 and the audio data obtained by the audio input unit 102 are stored as one file. In the reproduction mode, the compressed image data recorded on the recording medium 108 is reproduced by the recording / reproducing unit 107 and displayed on the display unit 105.

  In the moving image recording mode, first, the control unit 109 transmits a control signal to each block of the imaging apparatus 100 so as to shift to the shooting standby state, and performs the following operation.

  The imaging unit 101 converts an optical image of a subject captured by a photographing lens into an image signal by an imaging element, performs analog-digital conversion, image adjustment processing, and the like, and generates image data. Then, the obtained image data is transmitted to the display processing unit 104 and displayed on the display unit 105. The user prepares for shooting while viewing the screen displayed in this way.

  The audio input unit 102 digitally converts analog audio signals obtained by a plurality of microphones and processes the obtained digital audio signals to generate multi-channel audio data. Then, the obtained audio data is transmitted to the audio output unit 111 and is output as audio from the connected speaker 112 or an unillustrated earphone. The user can also adjust the manual volume to determine the recording volume while listening to the sound output in this way.

  Next, when a shooting start instruction signal is transmitted to the control unit 109 by the user operating the recording button of the operation unit 110, the control unit 109 transmits a shooting start instruction signal to each block of the imaging apparatus 100. Then, the following operation is performed.

  The imaging unit 101 converts an optical image of a subject captured by a photographing lens into an image signal by an imaging element, performs analog-digital conversion, image adjustment processing, and the like, and generates image data. Then, the obtained image data is transmitted to the display processing unit 104 and displayed on the display unit 105. Further, the obtained image data is transmitted to the memory 103.

  The audio input unit 102 digitally converts analog audio signals obtained by a plurality of microphones and processes the obtained digital audio signals to generate multi-channel audio data. Then, the obtained audio data is transmitted to the memory 103. If there is only one microphone, the obtained analog audio signal is digitally converted to generate audio data, and the audio data is transmitted to the memory 103.

  The encoding processing unit 106 reads out image data and audio data temporarily stored in the memory 103, performs predetermined encoding, and generates compressed image data, compressed audio data, and the like.

  Then, the control unit 109 synthesizes these compressed image data and compressed audio data, forms a data stream, and outputs the data stream to the recording / reproducing unit 107. When the audio data is not compressed, the control unit 109 synthesizes the audio data stored in the memory 103 and the compressed image data, forms a data stream, and outputs the data stream to the recording / reproducing unit 107.

  The recording / playback unit 107 writes the data stream to the recording medium 108 as one moving image file under the management of a file system such as UDF or FAT.

  The above operation is continued during shooting. When the user operates the recording button of the operation unit 110 and a shooting end instruction signal is transmitted to the control unit 109, the control unit 109 transmits a shooting end instruction signal to each block of the imaging apparatus 100. The following operations are performed.

  The imaging unit 101 and the audio input unit 102 stop generating image data and audio data, respectively. The encoding processing unit 106 reads the remaining image data and audio data stored in the memory, performs predetermined encoding, and stops the operation when generation of compressed image data, compressed audio data, and the like is completed. When the audio data is not compressed, the operation is naturally stopped when the generation of the compressed image data is finished.

  Then, the control unit 109 synthesizes the last compressed image data and the compressed audio data or audio data, forms a data stream, and outputs the data stream to the recording / reproducing unit 107.

  The recording / playback unit 107 writes the data stream to the recording medium 108 as one moving image file under the management of a file system such as UDF or FAT. When the supply of the data stream is stopped, the moving image file is completed and the recording operation is stopped.

  When the recording operation stops, the control unit 109 transmits a control signal to each block of the imaging apparatus 100 so as to shift to the shooting standby state, and returns to the shooting standby state.

  Next, in the playback mode, the control unit 109 transmits a control signal to each block of the imaging apparatus 100 so as to shift to the playback state, and performs the following operation.

  The recording / playback unit 107 reads a moving image file composed of compressed image data and compressed audio data recorded on the recording medium 108, and sends the read compressed image data and compressed audio data to the encoding processing unit 106.

  The encoding processing unit 106 decodes the compressed image data and the compressed audio data and transmits them to the display control unit 104 and the audio output unit 111, respectively. The display control unit 104 causes the display unit 105 to display the decoded image data. The audio output unit 111 outputs the decoded audio data from an external speaker built in or attached. As described above, the imaging apparatus 100 according to the present embodiment can record and reproduce images and sounds.

  In the present embodiment, the audio input unit 102 performs processing such as level adjustment processing of the audio signal obtained by the microphone when obtaining the audio signal. This process may always be performed after the apparatus is activated, may be performed after the shooting mode is selected, or may be performed after a mode related to audio recording is selected. . Further, in a mode related to audio recording, the above processing may be performed in response to the start of audio recording. In this embodiment, it is assumed that the above processing is performed at the timing when moving image shooting is started.

  FIG. 2 is a block diagram illustrating detailed configurations of the imaging unit 101 and the audio input unit 102 of the imaging apparatus 100 according to the present exemplary embodiment.

  The imaging unit 101 includes an optical system such as a lens 201 that captures an optical image of a subject, and an imaging element 202 that converts the optical image of the subject captured by the lens 201 into an electrical signal (image signal). The image processing unit 203 further converts an analog image signal obtained by the image sensor 202 into a digital image signal, performs image quality adjustment processing, forms image data, and transmits the image data to a memory. Furthermore, it has a lens control unit 204 having a known drive mechanism such as a position sensor for moving the lens 201 and a motor. In this embodiment, it is described that the imaging unit 101 includes the lens 201 and the lens control unit 204, but these may be detachable interchangeable lenses.

  For example, when a user operates the operation unit 110 to input instructions such as zoom operation and focus adjustment, the control unit 109 transmits a control signal (drive signal) for moving the lens to the lens control unit 204. In response to this control signal, the lens control unit 204 confirms the position of the lens 201 with a position sensor, and moves the lens 201 with a driving unit such as a motor. In addition, when the control unit 109 confirms the image obtained by the image processing unit 203 and the distance to the subject and automatically adjusts the distance, a control signal for driving the lens is transmitted. Further, when a so-called image stabilization function for preventing image blurring is provided, the control unit 109 outputs a control signal for moving the lens 201 based on vibration detected by a vibration sensor (not shown). This is transmitted to the lens control unit 204.

  At this time, the imaging apparatus 100 according to the present embodiment generates driving noise due to movement of the lens 201 and driving noise of a motor for moving the lens 201. In the present embodiment, the lens control unit 204 drives the lens in response to a control signal for driving the lens from the control unit 109. That is, the control unit 109 can know (detect or determine) the timing at which drive noise occurs.

  In this embodiment, the lens 201 can optically perform enlargement and reduction, for example, 6 times at the maximum and 1 time at the minimum. This is called optical zoom in this embodiment. In the optical zoom, in response to an instruction from the control unit 109, the lens control unit 204 moves the lens 201 to enlarge the optical image of the subject. Further, the image processing unit 203 has an electronic zoom (enlargement) function for outputting an image signal obtained by enlarging a part of the image signal obtained by the image sensor 202. In addition, an electronic zoom (reduction) function is provided for outputting an image signal in which an image range obtained by the image sensor 202 is widened and the image processing unit 203 reduces the image size.

  The voice processing of the voice input unit 102 includes a microphone 205 that converts voice vibration into an electrical signal and outputs the voice signal, and an AD converter 206 that converts an analog voice signal obtained by the microphone 205 into a digital voice signal. doing. Also, an FFT unit 207 that converts the time-domain digital audio signal subjected to AD conversion into a frequency-domain digital audio signal by performing fast Fourier transform at a certain sample timing of the frequency-domain digital audio signal converted by the FFT unit 207 A noise cancel unit 209 that compares the signal level of the frequency spectrum with the signal level of each frequency included in the frequency spectrum stored in the memory 208 and performs suppression processing for each frequency is provided. Further, the frequency domain digital signal after the suppression processing is inversely converted to the time axis to generate a digital audio signal, and the amplitude of the time domain digital audio signal generated by the iFFT unit 210 is set to a predetermined level. An audio level controller (hereinafter referred to as ALC) 211, and an audio processor 212 that performs predetermined processing on the audio signal to generate audio data and transmit it to the memory 103.

  The frequency spectrum recorded in the memory 208 in the present embodiment has, for example, a “frequency spectrum at the time of enlargement” corresponding to the movement of the lens 201 (hereinafter referred to as enlargement driving) in order to enlarge the optical image of the subject. ing. Further, it has a “frequency spectrum at the time of reduction” corresponding to when the lens 201 is moved (hereinafter referred to as reduction driving) in order to reduce the optical image of the subject. In this embodiment, the case where the lens 201 is moved has been described. However, the drive units other than this may have different frequency spectra, and the same processing may be performed.

  FIG. 3 is a diagram showing an example of the frequency spectrum recorded in the memory 208. In FIG. 3, (A1) shows a “frequency spectrum at the time of enlargement” corresponding to the case of enlargement driving. (B1) shows a “frequency spectrum at the time of reduction” corresponding to reduction driving. In the present embodiment, these are called noise profiles.

  In this embodiment, the digital audio signal is 48 KHz, 16-bit sampling. The frequency spectrum is calculated as a frequency spectrum by obtaining the signal level of the spectrum during the period in which the lens 201 is moved by the 512-point FFT unit 207. In this embodiment, “a frequency spectrum at the time of enlargement” (hereinafter referred to as noise profile A1) and “a frequency spectrum at the time of reduction” (hereinafter referred to as noise profile B1) are shown in FIG. 3 as examples. Of course, the drive units other than the lens 201 may have different frequency spectra, and the same processing may be performed.

  Next, noise cancellation processing when the lens 201 is moved by the driving unit of the lens control unit 204 will be described. A case will be described in which the lens 201 moves (enlargement drive) in order to enlarge the optical image of the subject by the operation of the operation unit 110 by the user. When the operation unit 110 is magnified by the user, the control unit 109 transmits a control signal to the lens control unit 204 so that the lens moves in the direction of enlarging the optical image of the subject. In response to this control signal, the lens control unit 204 drives a motor or the like so that the lens 201 moves in the direction of enlarging the optical image of the subject. At this time, while the lens 201 is moved by the drive of the drive unit, the control unit 109 transmits a control signal indicating that the lens 201 is enlarged and driven to the noise cancellation unit 209.

  The analog audio signal obtained by the microphone 205 is converted into a digital audio signal by the AD conversion unit 206, and the digital audio signal converted into the frequency domain by the FFT unit 207 is transmitted to the noise cancellation unit 209. Since the noise canceling unit 209 receives a control signal indicating that the lens 201 is driven to enlarge, from the control unit 109, the noise canceling unit 209 reads the noise profile A1 from the memory 208. FIG. 4 shows the noise canceling process of the noise canceling unit 209 using the noise profile A1. A frequency spectrum of the digital signal converted into the frequency domain by the FFT unit 207 is indicated as A2.

  In this embodiment, the digital audio signal is 48 KHz, 16-bit sampling. The frequency spectrum is calculated as the frequency spectrum A2 by obtaining the signal level of the spectrum by the 512-point FFT unit 207 in a certain short period while the lens 201 is moving. The levels at 512 points of the noise profile A1 and the frequency spectrum A2 are compared and classified into four stages to determine the suppression amount. As an example, as shown in FIG. 4, the degree of coincidence between the noise profile A1 and the frequency spectrum A2 is compared, and (1) 48 dB suppression, (2) 36 dB suppression, (3) 24 dB suppression, and (4) no suppression. Of course, the amount of suppression may be changed, and there are no four levels. The digital audio data that has been subjected to the suppression processing by the noise canceling unit 209 is inversely converted into a digital audio signal in the time domain by the iFFT unit 210, and then ALC processing by the ALC unit 211 and digital audio data by the audio processing unit 211. Predetermined processing is performed to form audio data and transmitted to the memory 103.

  As for the noise cancellation processing when the lens 201 is moved to reduce the optical image of the subject (reduction driving) by the operation of the operation unit 110 by the user, the noise cancellation unit 209 performs the lens 201 similarly to the enlargement driving. Receives a control signal from the control unit 109, reads the noise profile B1 from the memory 208, and compares the signal level with the frequency spectrum of the digital signal converted into the frequency domain by the FFT unit 207 Then, the suppression amount is determined by classifying into four stages. Of course, different noise profiles are stored in the memory 208 for the driving units other than the lens 201, and the FFT unit 207 changes the profile to be read out by the control signal of the control unit 109 and performs the noise canceling operation.

  In this embodiment, the case where there is one microphone has been described with reference to FIG. 2, but a plurality of microphones may be used. In this case, noise cancellation processing may be performed with a noise profile shared by microphones. However, if a noise profile corresponding to each microphone is provided individually, the noise reduction effect can be further enhanced. This is because it is desirable to individually reduce noise because the level of drive noise input to each microphone differs depending on the location of the microphone.

  Next, the noise profile correction in this embodiment will be described with reference to FIG. In FIG. 2, the level comparison unit 213 compares the signal level of the frequency spectrum of the digital audio signal in the frequency domain converted by the FFT unit 207 with the level of the noise profile stored in the memory 208. The correction determination unit 214 receives the comparison result of the level comparison unit 213 and determines whether or not to correct the noise profile stored in the memory 208 when the correction determination condition is satisfied. (Description of the correction determination condition will be described later). The correction unit 216 receives the correction determination result from the correction determination unit 214 and corrects the noise profile stored in the memory 208.

  Here, conditions for the correction determination unit 214 to perform correction determination will be described. First, the first condition will be described. The correction determination unit 214 determines whether or not to correct the noise profile stored in the memory 208 based on the comparison result of the level comparison unit. The correction determination unit 214 changes the correction determination unit based on the comparison result of the level comparison unit. As a first correction determination unit, the noise profile stored in the memory 208 is compared with the frequency spectrum of the digital audio signal after noise cancellation output from the noise cancellation unit 208. (Detailed processing will be described later.) Also, as the second correction determination means, the digital audio after noise cancellation output from the noise canceling unit 208 when the lens 201 is moved by the driving unit of the lens control unit 204. By comparing the average value of only the predetermined frequency band of the signal and the digital audio signal not yet processed with noise cancellation stored in the buffer 1 immediately before the movement of the lens 201 and the correction parameter stored in the memory 208. . (The correction parameter will be described later.) As a first condition for the correction determination unit 214 to perform correction determination, the correction parameter is stored in the memory 208 by the comparison result of the first correction determination unit or the second correction determination unit. Whether or not the noise profile needs to be corrected.

  Next, the second condition for the correction determination unit 214 to perform correction determination will be described. When the user instructs correction processing through the operation unit 110, the control unit 109 transmits a control signal indicating a correction processing command to the correction determination unit 214 and the correction unit 216. A second condition for the correction determination unit 214 to perform correction determination is whether or not the user has performed an operation for correction processing.

  Next, the third condition for the correction determination unit 214 to perform correction determination will be described. The control unit 109 includes a counter and a memory. The control unit 109 counts and records the number of times the lens 201 is driven. When a predetermined number of times recorded in the memory is exceeded, the correction determination unit 214 and the correction unit A control signal indicating a correction processing command is transmitted to 216. The control unit 109 resets the counter when the counter exceeds a specified number. Of course, the counter and the memory may be configured separately outside. A third condition for the correction determination unit 214 to perform correction determination is whether or not the number of driving times of the driving unit such as the lens 201 has exceeded a specified number. The correction determination unit 214 determines whether or not to perform correction when it is determined that the noise profile needs to be corrected under the condition 1 and when a correction operation is performed by the user under the condition 2. The correction determination unit 214 executes correction when it is determined that the noise profile needs to be corrected under the condition 1, and when the number of driving times of the driving unit such as the lens 201 exceeds the specified number of times under the condition 3. Judgment.

  Next, the sound level correction process of the sound input unit 102 in this embodiment will be described. First, a case where the lens 201 moves (enlargement drive) in order to enlarge the optical image of the subject by the operation of the operation unit 110 by the user will be described. When the lens 201 is moved to enlarge the optical image of the subject (enlargement driving) by the operation of the operation unit 110 by the user, the control unit 109 drives the lens 201 with respect to the correction determination unit 214 and the correction unit 216. While moving by driving the part, a control signal indicating that the lens 201 is enlarged is transmitted. The analog audio signal obtained by the microphone 205 is converted into a digital audio signal by the AD conversion unit 206, and the frequency domain digital audio signal converted by the FFT unit 207 is transmitted to the level comparison unit 213. Here, the level comparison unit 213 compares the signal level of the frequency spectrum of the digital audio signal from the FFT unit 207 with the level of the noise profile A1 stored in the memory 208 during expansion driving.

  In the embodiment, the digital audio signal is 48 KHz, 16-bit sampling. The frequency spectrum is calculated as the frequency spectrum X by obtaining the spectrum by the 512-point FFT unit 207 in a certain short period immediately before the lens 201 is enlarged and driven. FIG. 5 shows the above-described noise profile A1 and the frequency spectrum X of the digital audio signal immediately before the lens 201 is magnified. The correction determination unit 214 determines the correction determination unit described above based on the result of the level comparison unit 213. When the frequency spectrum X is lower than the noise profile A1 in the entire frequency band, for example, when there is a relationship between the frequency spectrum X1 and the noise profile A1, the correction determination unit 214 selects the first correction determination unit described above. When the frequency spectrum X does not fall below the noise profile A1 in the entire frequency band, the correction determination unit 214 compares the average value of a specific frequency band determined in advance for each of the frequency spectrum X and the noise profile A1. In the average value of the predetermined specific frequency band, when the frequency spectrum X is lower than the noise profile A1, for example, in the predetermined specific frequency band F1 like the relationship between the frequency spectrum X2 and the noise profile A1, the frequency When the average value of the spectrum X is lower than the average value of the noise profile A1, the correction determination unit 214 selects the second correction determination unit described above. Even in the average value of a predetermined specific frequency band, when the frequency spectrum X exceeds the noise profile A1, for example, when there is a relationship between the frequency spectrum X3 and the noise profile A1, the correction determination unit 214 performs correction determination. do not do.

  Here, the first correction determination means will be described. The correction determination unit 214 stores the signal level of the frequency spectrum of the audio signal immediately before the lens 201 stored in the buffer before being magnified and the frequency spectrum during the magnification driving of the lens 201 on which the noise cancellation processing has been performed by the noise cancellation unit 209. Compare the 512 point levels. The buffer 215 obtains the spectrum signal level by the 512-point FFT unit 207 from time to time in a certain short period and stores it as a frequency spectrum. As a result of comparing the levels of 512 points of the above-described two types of frequency spectra (hereinafter, the level comparison process is described as profile check 1), the correction determination unit 214 finds a difference larger than a predetermined threshold value. If calculated, warn that point. For example, as shown in FIG. 6, the difference between the frequency spectrum X1a of the audio signal immediately before the expansion drive and the frequency spectrum X1b of the audio signal being expanded is greater than the threshold at the points in the frequency bands F3 and F4. If so, warn the point in that frequency band. Further, the correction determination unit 214 performs the above-described profile check 1 a predetermined number of times, and determines a point where the number of warnings is equal to or greater than the predetermined number as a correction execution point. For example, as shown in FIG. 6, when the level difference of the points in the frequency bands F3 and F4 of the frequency spectrum X1a and the frequency spectrum X1b exceeds a threshold value for a predetermined number of times or more and a warning is given, the points in the frequency bands of F3 and F4 are The correction means 1 is determined as the execution point.

  Next, the second correction determination unit will be described. The correction determination unit 214 is subjected to noise cancellation processing by the noise cancellation unit 209 and the average value of a predetermined specific frequency band of the frequency spectrum of the audio signal immediately before the lens 201 stored in the buffer is enlarged and driven. The average value of a predetermined specific frequency band of the frequency spectrum during expansion driving of the lens 201 is compared. For example, as shown in FIG. 7, in the predetermined specific frequency band F1, the average value of the frequency spectrum X2a of the sound signal immediately before the expansion driving and the frequency spectrum X2b during the expansion driving subjected to the noise cancellation processing are respectively calculated. The difference α is calculated. Here, the correction determination unit 209 calculates the correction level from the correction parameter stored in the memory 208 and the difference α between the average values of the frequency spectra in each of the specific frequency bands F1 calculated above.

  Here, the correction parameters will be described. FIG. 8 is a diagram showing correction parameters. The horizontal axis indicates the average level of a predetermined specific frequency band F1 of the frequency spectrum of the audio signal for a certain period during which the lens 201 is not expanded and the vertical axis indicates the audio for a certain period during the period during which the lens 201 is expanded. A level obtained by subtracting an average level of a predetermined specific frequency band F1 of a frequency spectrum of an audio signal during a certain period of time that is not expanded from the average level of a predetermined specific frequency band F1 of the frequency spectrum of the signal. . When obtaining the above relationship, the sound pressure level [dB] is calculated as sound pressure [μPa] because it is a relative scale. The level of the audio signal input during a certain period when the driving unit is not driven, that is, the sound pressure level of the environmental sound is represented as S [dB], and the sound pressure is represented as s [μPa], and the driving unit is driven. An audio signal input for a certain period when the drive unit is not driven, that is, a sound pressure level of the drive unit drive sound is N [dB] and a sound pressure is n from a level of the audio signal input for a certain period. It is expressed as [μPa], and the level of the audio signal input for a certain period during which the driving unit is driven, that is, the sound pressure level obtained by adding the driving unit driving sound and the environmental sound is S + N [dB], and the sound pressure is s + n. Let it be expressed as [μPa]. At this time, the calculation formula described later holds.

S = 20 log 10 (s ² / p 0 ² )
N = 20 log 10 (n ² / p0 ² )
S + N = 20 log 10 (10 ^ (S / 10) + 10 ^ (N / 10))
* P0 is the reference value (p0 = 20μPa)
From the above equation, in FIG. 8, the horizontal axis indicates the average level of a predetermined specific frequency band F1 of the frequency spectrum of the audio signal for a certain period of time that is not expanded and the vertical axis indicates the constant that is expanded and driven. The average level of the predetermined specific frequency band F1 of the frequency spectrum of the audio signal for a certain period not driven to be expanded from the average level of the predetermined specific frequency band F1 of the frequency spectrum of the audio signal for a certain period of time It leads the level relationship minus.

  The correction determination unit 214 has the difference α between the average value of the frequency spectrum in each specific frequency band F1 calculated as described above and the level on the horizontal axis being the same level and the default level β on the correction parameter. (Hereinafter, this calculation process is described as profile check 2). If a difference larger than a predetermined threshold is calculated as a result of the profile check 2, the correction determination unit 214 warns. Further, the correction determination unit 214 performs the above-described profile check 2 a predetermined number of times, and determines that the correction unit 2 is executed when the number of warnings exceeds a predetermined number.

  Subsequently, the correction determination unit 214 determines the execution of correction when the above-described correction determination conditions 1 and 2 are satisfied, or when the conditions 1 and 3 are satisfied. In this case, the correction determination unit 214 also assigns the execution point of the correction unit 1 to the determination in the case of the determination in the correction determination unit 1 or the determination in the correction determination unit 2 in the condition 1. To do.

  Next, the correction unit 216 receives the determination result of the correction determination unit 214 and executes correction processing. Here, the correction process 1 when the correction determination unit 214 determines the correction execution by the correction determination unit 1 will be described.

  When the lens 201 is moved to enlarge the optical image of the subject (enlarged drive) by the operation of the operation unit 110 by the user, the control unit 109 drives the lens 201 with respect to the correction determination unit 214 and the correction unit 216. While moving by driving the part, a control signal indicating that the lens 201 is enlarged is transmitted. The analog audio signal obtained by the microphone 205 is converted into a digital audio signal by the AD conversion unit 206, and the frequency domain digital audio signal converted by the FFT unit 207 is transmitted to the level comparison unit 213. Here, the level comparison unit 213 compares the signal level of the frequency spectrum of the digital audio signal from the FFT unit 207 with the level of the noise profile A1 stored in the memory 208 during expansion driving.

  In the embodiment, the digital audio signal is 48 KHz, 16-bit sampling. The frequency spectrum is calculated as the frequency spectrum Y by obtaining the signal level of the spectrum by the 512-point FFT unit 207 in a certain short period immediately before the lens 201 is enlarged and driven. FIG. 9 shows the noise profile A1 and the frequency spectrum Y1 of the digital audio signal immediately before the lens 201 is driven to be enlarged.

  The correction unit 216 receives the result from the level comparison unit 213 and advances the execution of the correction process when the frequency spectrum Y1 is lower than the noise profile A1 in the frequency band of the correction unit 1 execution point as shown in FIG. Conversely, when the frequency spectrum Y1 exceeds the noise profile A1, the execution of the correction process is stopped. Subsequently, the correction unit 216 is in the process of enlarging and driving the signal level of the frequency spectrum of the audio signal immediately before enlarging the lens 201 stored in the buffer 217 and the noise 201 subjected to the noise canceling process by the noise canceling unit 209. The levels of the execution points of the correction means 1 of the frequency spectra are compared. The buffer 215 obtains the spectrum signal level by the 512-point FFT unit 207 from time to time in a certain short period and stores it as a frequency spectrum. The correction unit 216 compares the levels of the above-described two types of frequency spectrums for the correction means 1 execution point (hereinafter, the level comparison process is described as profile correction 1), and as a result, is larger than a predetermined threshold value. When the difference is calculated, the level of the noise profile A1 stored in the memory 208 is corrected. For example, as shown in FIG. 10, the difference between the frequency spectrum Y1a of the audio signal immediately before the enlargement driving and the frequency spectrum Y1b of the audio signal being enlarged is greater than the threshold at the points in the frequency bands F3 and F4. In this case, correction for the calculation result is performed on the level of the point in the frequency band of the noise profile A1 stored in the memory 208. The process of profile correction 1 described above is performed in the same way even when the lens 201 is driven to reduce. The object to be compared is only a noise profile at the time of reduction driving.

  Next, the correction process 2 when the correction determination unit 214 determines the correction execution by the correction determination unit 2 will be described. The processing up to the comparison result of the level comparison unit 213 is the same as the correction processing 1 described above. As described above, FIG. 5 shows the noise profile A1 and the frequency spectrum X of the digital audio signal immediately before the lens 201 is magnified. In response to the comparison result of the level comparison unit 213, the correction unit 216 has an average value of the frequency spectrum X2 of the noise profile A1 in a specific frequency band F1 that is predetermined as in the relationship between the frequency spectrum X2 and the noise profile A1. When the average value is below, the correction unit 216 advances the execution of the correction process. Even in the predetermined average value of a specific frequency band, when the frequency spectrum X exceeds the noise profile A1, the execution of the correction process is stopped.

  Subsequently, the correction unit 216 performs noise cancellation processing by the noise cancellation unit 209 using the average value of a predetermined specific frequency band of the frequency spectrum of the audio signal immediately before the lens 201 stored in the buffer 217 is enlarged and driven. The average value of a predetermined specific frequency band of the frequency spectrum during enlargement driving of the applied lens 201 is compared. As processing contents, processing similar to that of the correction determination means 2 is performed. For example, as shown in FIG. 7 described above, the average of the frequency spectrum X2a of the audio signal immediately before the expansion driving and the frequency spectrum X2b during the expansion driving subjected to the noise canceling process in the predetermined specific frequency band F1 respectively. The value difference α is calculated. Here, the correction unit 216 calculates a correction level from the correction parameter stored in the memory 208 and the difference α between the average values of the frequency spectra in each of the specific frequency bands F1 calculated above. The correction parameters in FIG. 8 are as described above. The correction unit 216 calculates the difference between the average value difference α of the frequency spectrum in each of the calculated specific frequency bands F1 described above and the level on the horizontal axis and the default level β on the correction parameter. (Hereinafter, this calculation process is described as profile correction 2).

  When a difference larger than a predetermined threshold is calculated as a result of the above-described profile correction 2, the correction unit 216 calculates the level of the point in the frequency band of the noise profile A1 stored in the memory 208. Correct the result. The process of profile correction 1 described above is performed in the same way even when the lens 201 is driven to reduce. The object to be compared is only a noise profile at the time of reduction driving.

  In the present embodiment, the case where one system of audio is input has been described, but the present invention can be applied even when the number of channels is more than that.

  In the present embodiment, the imaging apparatus has been described. However, the audio processing performed by the audio input unit 102 according to the present embodiment is any apparatus that records or inputs external audio. Even can be applied. For example, you may apply to an IC recorder, a mobile telephone, etc.

100 imaging device, 101 imaging unit, 102 voice input unit, 103 memory,
104 display control unit, 105 display unit, 106 encoding processing unit

Claims (4)

Imaging means;
Driving means for moving the optical system of the imaging means;
An FFT unit for converting time-series audio data into a frequency spectrum;
A noise cancellation unit that performs level suppression by comparing the signal level of the frequency spectrum of the input audio signal and the level of the noise profile for each frequency;
An iFFT unit that returns the frequency spectrum level-suppressed by the noise cancellation unit to time-series audio data;
A level comparison unit that compares the signal level of the frequency spectrum and the level of the noise profile;
A correction determination unit that calculates a frequency shift or a level shift between the noise profile and a frequency spectrum of a target drive unit, and determines whether to execute correction according to the result;
A correction unit that calculates and corrects the correction level of the noise profile;
Control means for controlling the adjusting means according to whether or not the drive unit is driven,
When the input audio level falls below a predetermined threshold, the drive unit compares the signal level between the frequency spectrum before driving and the frequency spectrum whose level is suppressed by the noise canceling unit during driving, and corrects the level of the noise profile. An imaging apparatus characterized by:   If the signal level of the frequency spectrum is equal to or less than a predetermined first threshold value, the correction determination unit is configured by the signal level of the frequency spectrum before the driving unit is driven and the noise canceling unit that is driving the driving unit. 2. The imaging apparatus according to claim 1, wherein the signal levels of the frequency spectra whose levels are suppressed are compared, and it is determined whether or not to execute correction according to the comparison result.   If the signal level of the frequency spectrum is equal to or less than a predetermined second threshold value, the correction determination unit is configured to output a frequency spectrum whose level is suppressed by a noise canceling unit that is driving the driving unit in a predetermined frequency band. The signal level and the drive unit compare an average value of a signal level of a frequency spectrum before driving with a correction parameter, and determine whether or not to execute correction according to the comparison result. Imaging device.   A condition when correction is instructed from the operation means or when the number of times the drive unit has been driven exceeds a predetermined number of times and a condition when a correction execution determination result is issued by the correction determination unit The imaging apparatus according to claim 1, wherein the correction determination unit determines whether to execute a correction process based on a sum condition.