JP2014131149A - Image pick-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pick-up device in which wind noise can be suppressed by detecting the indoor and outdoor environment, and changing the indoor and outdoor audio frequency characteristics depending on the difference of shooting conditions.SOLUTION: An indoor voice processing circuit 1101 subtracts a voice signal of an Rch microphone 1091 from a voice signal of a Lch microphone 1092 by supplying a voice signal, passed through a low-pass filter LPF 1106, in negative value, to an adder 1107. The indoor voice processing circuit 1101 also subtracts a voice signal of a Lch microphone 1092 from a voice signal of an Rch microphone 1091 by supplying a voice signal, passed through a low-pass filter LPF 1105, in negative value, to an adder 1108. A desired level is given to the voice signal thus obtained and frequency characteristic correction is performed in correction circuits 1109, 1110, and then the sounds of Lch and Rch being recorded are outputted from output terminals 1103, 1104 to a voice A/D converting section 111.

Description

  The present invention relates to an imaging apparatus.

  Conventionally, the sound of the imaging device has been amplified by a microphone amplifier from a microphone mounted on the housing of the imaging device, and then input to a recording circuit and recorded on a recording medium. However, in such a configuration, the characteristics are constant regardless of the shooting conditions, so the sound in the outdoor space and the sound in the indoor space cannot be compatible, and there is a problem that the sound becomes halfway. It was.

  In order to solve such problems, there has been proposed a camera-integrated magnetic recording / reproducing apparatus in which the characteristics of an audio signal to be recorded can be appropriately switched in accordance with the color temperature detection signal of the camera unit of the imaging apparatus. (See Patent Document 1).

JP-A-5-161101

  However, according to the proposal of Patent Document 1, the frequency of the audio signal is lower in the vicinity of 100 Hz and higher in the vicinity of 8 KHz in outdoor shooting than in indoor shooting, based on the experience of the inventor and a questionnaire survey to a plurality of people. It has been confirmed that it is better to lift each 3 to 6 dB. Therefore, it is desirable that the outdoor correction circuit 3 and the indoor correction circuit 4 be configured so that this characteristic is obtained. There was a problem that the characteristics of the wind noise in question were not taken into consideration.

    Further, when two microphones are arranged for Lch and Rch in the housing of the image pickup apparatus and stereo sound is recorded, the distance between the microphones becomes short. Therefore, there is almost no difference between both channels of the audio signal to be recorded, especially for low frequencies, and there is a difference in the original stereo component according to the position of the sound source and the two microphones as the frequency becomes higher. To do. On the other hand, wind noise mainly includes low-frequency components of 1 KHz or less, and there is a problem that wind noise is not considered to be generated without correlation between Lch and Rch microphones.

  The present invention has been made in view of the above problems, detects the environment between indoors and outdoors, emphasizes the stereo feeling indoors and outdoors according to the difference in shooting conditions, and enhances wind noise. An object of the present invention is to provide an image pickup apparatus that can be suppressed.

In order to solve the above problems, the present invention comprises the following means.
That is,
An imaging unit for performing imaging processing;
An optical sensor for detecting ambient light imaged by the imaging unit;
A discriminator for discriminating whether the environment to be imaged is indoor or outdoor from the output of the optical sensor;
A first microphone for acquiring sound and converting it to a first sound signal;
A second microphone for acquiring sound and converting it to a second sound signal;
An audio signal processing unit that includes an indoor audio signal circuit and an outdoor audio signal circuit, processes the first audio signal and the second audio signal, and converts them into first and second audio signals to be recorded, respectively; Have
According to the discrimination result of the discrimination unit, either the indoor audio signal circuit or the outdoor audio signal circuit is selected, and a process of converting into an audio signal to be recorded in the audio signal processing unit is performed. An imaging device.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to reduce a wind noise effectively, the imaging device which can minimize degradation of an audio | voice signal can be provided, enhancing a stereo feeling.

1 is an external view of an imaging apparatus 1 according to a first embodiment. 1 is a block diagram showing an internal configuration of an imaging apparatus 1 according to a first embodiment. 1 is a block diagram showing a configuration of an indoor audio signal processing circuit according to a first embodiment; 1 is a block diagram showing a configuration of an outdoor audio signal processing circuit according to a first exemplary embodiment; It is a figure which shows an example of a wind noise spectrum. It is a figure which shows an example of the audio | voice signal frequency characteristic in the case of the outdoors. It is a figure which shows an example of the audio | voice signal frequency characteristic in the case of indoor.

<Embodiment 1>
Embodiments of the present invention will be described below with reference to the drawings. The imaging apparatus 1 according to the present embodiment can capture a moving image and a still image. An external perspective view of the imaging apparatus 1 is shown in FIG.

  FIG. 1 is an external view showing an overall configuration of an imaging apparatus 1 according to the present embodiment. In the following description, an xyz orthogonal coordinate system as shown in the figure is used for clarity of explanation.

  Here, the x-axis indicates the front-rear direction of the imaging apparatus 1, the y-axis indicates the up-down direction (vertical direction) of the imaging apparatus 1, and the z-axis indicates the left-right direction (lateral direction, width direction) of the imaging apparatus 1. ing. That is, the x direction is a direction parallel to the optical axis of the lens provided in the imaging apparatus 1, and the y direction and the z direction are directions perpendicular to the optical axis of the lens provided in the imaging apparatus 1. Further, the direction is specified based on the user holding the imaging device 1.

  That is, the + x side is the rear side (opposite side of the lens barrel opening side), the -x side is the front side (lens barrel opening side), the + y side is the upper side, the -y side is the lower side, the + z side is the left side,- The z side is the right side. Of course, the above-described directions are relative and change according to the orientation of the imaging device 1.

  Although FIG. 1 illustrates a handy-type imaging device 1 that can be held by a human hand, the imaging device 1 can be fixed to a wall surface of a building or a residence. An Lch microphone 1092 and an Rch microphone 1091 are provided at the lower part on the opening side of the lens barrel of the imaging device 1.

  Next, the internal configuration of the imaging apparatus 1 will be described. FIG. 2 is a block diagram showing an internal configuration of the imaging apparatus 1 according to the present embodiment. The imaging apparatus 1 includes an imaging unit 100 including a zoom lens 101, a focus lens 102, a diaphragm 103, and an imaging element 104. The zoom lens 101 is moved along the optical axis LA by a zoom actuator (not shown). Similarly, the focus lens 102 moves along the optical axis LA by a focus actuator (not shown). The diaphragm 103 operates by being driven by a diaphragm actuator (not shown). The imaging element 104 is configured by a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like.

  Imaging using the imaging apparatus 1 is performed according to the following procedure. The image sensor 104 photoelectrically converts light that has passed through the zoom lens 101, the focus lens 102, and the diaphragm 103 to generate an analog image signal of the subject. After the analog image signal processing unit 105 amplifies the analog image signal, the image A / D conversion unit 106 converts the amplified signal into digital image data. The image input controller 107 takes in digital image data output from the image A / D conversion unit 106 as imaging data and stores it in the main memory 205 via the bus 200.

  Based on a command from the central control unit 400 via the bus 200, the digital signal processing unit 108 captures imaging data stored in the main memory 205, and performs predetermined signal processing on the RGB signal to obtain a luminance signal. Data consisting of color difference signals is generated. The digital signal processing unit 108 also performs various digital corrections such as offset processing, white balance adjustment processing, gamma correction processing, RGB complementation processing, noise reduction processing, contour correction processing, distortion correction processing, color tone correction processing, and light source type determination processing. Do.

  The processing of the audio signal will be described. In order to simplify the description, it is assumed that the microphone includes the microphone 109. The microphone 109 picks up surrounding sounds at the time of imaging and generates an analog sound signal. After the analog audio signal processing unit 110 amplifies the analog audio signal, the audio A / D conversion unit 111 converts the amplified signal into digital audio data. The audio input controller 112 stores the digital audio data output from the audio A / D converter 111 in the main memory 205 together with the imaging data. Detailed operation of the analog audio signal processing unit 110 will be described later.

  The multiplexing unit 113 multiplexes the compressed image data and digital audio data stored in the main memory 205 to generate stream data. Further, the multiplexing unit 113 performs demultiplexing processing on the stream data stored in the card-type recording medium 302, and separately generates compressed video data and compressed audio data.

  The compression / decompression processing unit 201 performs predetermined compression processing on the imaging data and digital audio data stored in the main memory 205 in accordance with an instruction from the central control unit 400 via the bus 200 to generate compressed data. The compression / decompression processing unit 201 also performs decompression processing of a predetermined format on the compressed video data and the compressed audio data stored in the card type recording medium 302 and the like in accordance with a command from the central control unit 400, so that uncompressed data Is generated. Note that in the imaging apparatus 1 according to the present embodiment, a compression method conforming to the JPEG standard is used for still images, and MPEG2 standard or AVC / H. A compression method conforming to the H.264 standard is adopted.

  The sound / image processing unit 202 performs predetermined image processing on the digital data read from the main memory 205 in accordance with an instruction from the central control unit 400 via the bus 200. For example, image data for various processes such as a menu image and an OSD image is generated, and the image data is superimposed on the original image data read from the main memory 205 and output to the liquid crystal monitor 304. With this output, the image displayed on the liquid crystal monitor 304 is a combination of various image data. Instead of the liquid crystal monitor 304, other monitors such as an organic EL (Electro-Luminescence) monitor can be used.

  The ROM 203 is connected to the central control unit 400 via the bus 200, and stores a control program executed by the central control unit 400, various data necessary for control, and the like. The flash ROM 204 stores various setting information related to the operation of the imaging apparatus 1, such as user setting information. For example, the imaging apparatus 1 stores in advance in the flash ROM 204 several imaging modes and imaging condition settings according to each mode in accordance with various imaging situations. And before starting imaging, the user can perform imaging under optimal imaging conditions by selecting an optimal mode from each mode. For example, a “portrait mode” suitable for capturing a specific person, a “sport mode” suitable for capturing an athletic meet, or a “night view mode” suitable for capturing a dark place such as a night view.

  The main memory 205 is used as a temporary storage area for imaged data (moving images and still images). The main memory 205 stores the multiplexed stream data that is held in the card-type recording medium 302 in response to a command from the central control unit 400. The main memory 205 holds various data referred to by the central control unit 400.

  The media control unit 206 controls data writing to and data reading from the card-type recording medium 302 through the card I / F 301 in accordance with a command from the central control unit 400. The card-type recording medium 302 is an external memory such as an SD card or a compact flash (registered trademark), and is provided so as to be removable from the imaging apparatus 1.

  The gyro sensor 207 detects changes in triaxial acceleration and angular velocity, and detects the pan / tilt amount and the vertical and horizontal camera shake amounts of the imaging apparatus 1. The clock 208 generates information on the generation date and time of imaging data.

  The liquid crystal monitor 304, the speaker 305, the operation unit 306, and the input / output terminal 307 are connected to the input / output I / F 303. The liquid crystal monitor 304 displays an image generated from various image data such as imaging data temporarily recorded in the main memory 205 and various menu image data. The speaker 305 outputs sound temporarily recorded in the main memory 205, for example. As described above, the operation unit 306 includes an operation key including a release switch and a power switch, a cross key, a joystick, a touch panel superimposed on the liquid crystal monitor 304, and the like. Accept operation input. The input / output terminal 307 is connected to a pan head, a television monitor, a PC (Personal Computer), or the like capable of pan / tilt operation.

  The wireless module 309 transmits and receives signals to and from the operation terminal via the bus 200 and the wireless I / F 308. Specifically, the wireless module 309 performs communication processing conforming to a wireless LAN standard such as Wi-Fi. Thereby, communication with the operation terminal becomes possible.

  The central control unit 400 is configured by a semiconductor integrated circuit including a CPU, a ROM storing various programs, a RAM as a work area, and the like, and is an imaging device for imaging, displaying various images, and transmitting / receiving information related to cooperative photography. 1 Controls overall processing.

  The optical sensor 500 is provided in a location where the light in the imaging environment can be detected, such as in the vicinity of the opening of the lens barrel of the imaging device 1. The optical sensor may detect the entire natural light range, or may be a so-called infrared sensor that receives light in the infrared region, converts it into an electrical signal, extracts necessary information, and applies it. In this description, an example using an infrared sensor will be described.

  An infrared sensor that is the optical sensor 500 receives light in the infrared region, converts it into an electrical signal, and outputs it to the central controller 400. The central controller 400 detects flicker that is the level and cycle of the electric signal from the electric signal. Level and flicker thresholds are set, and with respect to the threshold values, a large level flicker is determined to be indoor, and other patterns such as level large flicker large, level small flicker large, and level small flicker small are determined to be indoor.

  The central control unit 400 includes a determination unit that determines whether it is indoor or outdoor. However, the determination unit may perform detection using another circuit block. In addition, since the optical sensor 500 is configured by an infrared sensor and the determination unit is configured to determine whether it is indoor or outdoor from the output of the optical sensor 500, indoor or outdoor more accurately than using a white balance sensor. Can be detected.

  Next, the detailed operation of the analog audio signal processing unit 110 will be described with reference to FIGS. FIG. 3 shows a block configuration of the indoor audio processing circuit 1101 and FIG. 4 shows a block configuration of the outdoor audio processing circuit 1102. When the analog sound signal processing unit 110 selects the indoor sound processing circuit 1101 and determines that it is outdoors when the determining unit provided in the central control unit 400 determines whether it is indoor or outdoor. The analog audio signal processing unit 110 selects the outdoor audio processing circuit 1102.

  As shown in FIG. 3, the indoor audio processing circuit 1101 negatively outputs to the adder 1107 an audio signal obtained by passing the low-pass filter LPF 1106 from the audio signal of the Lch microphone 1092 to the audio signal of the Rch microphone 1091. Supply and subtract. The audio signal obtained in this manner is subjected to desired level and frequency characteristic correction by the correction circuit 1109, and the output of the Lch sound to be recorded is output from the output terminal 1103 to the audio A / D converter 111.

  Similarly, the audio signal obtained by passing the LPF 1105 which is a low-pass filter from the audio signal of the Rch microphone 1091 to the audio signal of the Lch microphone 1092 is supplied to the adder 1108 with a negative value and subtracted. The audio signal obtained in this manner is subjected to desired level and frequency characteristic correction by the correction circuit 1110, and the output of the Rch sound to be recorded is output from the output terminal 1104 to the audio A / D converter 111. Correction of desired levels and frequency characteristics in the correction circuits 1109 and 1110, but the level is adjusted so as to adapt to the dynamic range of the entire audio processing circuit, and the frequency characteristics are corrected according to the conditions for recording the audio signal. Circuit. The following correction circuit performs the same operation.

  As described above, in the case where two microphones are arranged for Lch and Rch in the housing of the imaging apparatus and stereo sound is recorded, the distance between the microphones becomes short. Therefore, there is almost no difference between both channels of the audio signal to be recorded, especially for low frequencies, and there is a difference in the original stereo component according to the position of the sound source and the two microphones as the frequency becomes higher. To do. On the other hand, wind noise mainly includes low frequency components of 1 KHz or less, and wind noise is generated without correlation between the Lch and Rch microphones.

  Therefore, when it is determined that the imaging environment is indoor, the indoor audio processing circuit 1101 subtracts the audio signal obtained by passing the other input audio signal through the LPF from the main audio signal, so that it is used for Lch and Rch. The sound corresponding to the separation distance between the two microphones is subtracted to output a stereo component.

  As shown in FIG. 4, the outdoor audio processing circuit 1102 supplies an audio signal obtained by passing the audio signal of the Rch microphone 1091 to the audio signal of the Lch microphone 1092 through the high-pass filter HPF 1112 to the adder 1113. to add. The audio signal obtained in this manner is subjected to desired level and frequency characteristic correction by the correction circuit 1115, and the output of the Lch sound to be recorded is output from the output terminal 1103 to the audio A / D converter 111.

  Similarly, the outdoor audio processing circuit 1102 supplies the audio signal obtained by passing the audio signal of the Lch microphone 1092 to the audio signal of the Rch microphone 1091 through the HPF 1111 which is a high-pass filter to the adder 1114 for addition. The audio signal obtained in this way is subjected to desired level and frequency characteristic correction by the correction circuit 1116, and the output of the Lch sound to be recorded is output from the output terminal 1104 to the audio A / D converter 111.

  Therefore, when the imaging environment is determined to be outdoor, the outdoor audio processing circuit 1102 mainly adds an audio signal obtained by passing the other input audio signal to the HPF to the main audio signal, thereby reducing the frequency to 1 KHz or less. Wind noise generated without correlation between the Lch and Rch microphones in the frequency component is effectively reduced.

  FIG. 5 shows an example of a wind noise spectrum. Since the stereo emphasis circuit mounted on the image pickup apparatus 1 performs LPF mixing, wind noise mainly composed of low-band frequencies tends to be emphasized. Wind noise enhancement can be suppressed by changing the stereo enhancement circuit indoors and outdoors.

  6 and 7 show examples of frequency characteristics when the sound source is on the right side. FIG. 6 shows an example of a frequency characteristic diagram when the sound source is outdoors on the right side. FIG. 7 shows an example of a frequency characteristic diagram when the sound source is indoors in the right side.

  Wind noise is a signal mainly composed of low-frequency frequencies, and has a band of approximately 1 KHz or less. When outdoors, wind noise is prevented from being affected by reducing stereo emphasis in the band below 1 kHz.

  As described above, the audio signal processing unit 110 selects the indoor audio processing circuit 1101 and the outdoor audio processing circuit 1102 according to the determination of indoor or outdoor. The frequency characteristics / sensitivity including low frequencies can be optimized indoors in a small number of indoors, and the voice recording performance can be improved indoors.

  In the above-described example, the indoor audio processing circuit and the outdoor audio processing circuit of the analog audio signal processing unit are selected according to whether indoor or outdoor, but the subsequent stage of the audio A / D conversion unit. An indoor audio processing circuit and an outdoor audio processing circuit may be selected in a block such as an audio input controller.

DESCRIPTION OF SYMBOLS 100 Image pick-up part 101 Zoom lens 102 Focus lens 103 Diaphragm 104 Image pick-up element 105 Analog image signal processing part 106 Image A / D conversion part 107 Image input controller 108 Digital signal processing part 109 Microphone 1091 Rch microphone 1092 Lch microphone 110 Analog audio signal Processing unit 1101 Indoor audio processing circuit 1102 Outdoor audio processing circuit 1105, 1106 LPF
1107, 1108, 1113, 1114 Adders 1109, 1110, 1115, 1116 Correction circuits 1111 and 1112 HPF
111 Audio A / D Conversion Unit 112 Audio Input Controller 113 Multiplexing Unit 201 Compression / Expansion Processing Unit 202 Audio / Image Processing Unit 203 ROM
204 Flash ROM
205 Main memory 206 Media control unit 207 Gyro sensor 210 Image holding unit 211 User table 301 Card I / F
302 Card type recording medium 303 Input / output I / F
304 LCD monitor 305 Speaker 306 Operation unit 307 Input / output terminal 308 Wireless I / F
309 Wireless module 400 Central control unit 500 Optical sensor

Claims (3)

An imaging unit for performing imaging processing;
An optical sensor for detecting ambient light imaged by the imaging unit;
A discriminator for discriminating whether the environment to be imaged is indoor or outdoor from the output of the optical sensor;
A first microphone for acquiring sound and converting it to a first sound signal;
A second microphone for acquiring sound and converting it to a second sound signal;
An audio signal processing unit that includes an indoor audio signal circuit and an outdoor audio signal circuit, processes the first audio signal and the second audio signal, and converts them into first and second audio signals to be recorded, respectively; Have
According to the discrimination result of the discrimination unit, either the indoor audio signal circuit or the outdoor audio signal circuit is selected, and a process of converting into an audio signal to be recorded in the audio signal processing unit is performed. An imaging device.   The imaging apparatus according to claim 1, wherein the determination unit determines whether the environment for imaging is indoor or outdoor from a light level output of the optical sensor and flicker of the light level. The indoor audio signal circuit includes a first audio signal, a second audio signal, and a second audio signal obtained by subtracting an audio signal obtained by passing a low-pass filter from the second audio signal. A signal obtained by subtracting an audio signal that has been passed through a low-pass filter from the first audio signal to the first audio signal as the second audio signal to be recorded;
The outdoor audio signal circuit in the previous period includes the first audio signal, the second audio signal, a signal obtained by adding an audio signal obtained by passing a high-pass filter to the second audio signal, and the second audio signal. 3. The imaging according to claim 1, wherein a signal obtained by adding a sound signal obtained by passing a high-pass filter from a signal to the first sound signal is used as the second sound signal to be recorded. apparatus.

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