JP6104067B2 - Lens driving abnormal noise inspection method and lens driving abnormal noise inspection device - Google Patents

Description

  The present invention relates to a lens driving abnormal sound inspection method and a lens driving abnormal sound inspection device for determining whether or not a lens driving sound is normal.

  In a lens barrel used in an imaging apparatus such as a digital camera, when an abnormal noise is generated due to driving of a lens group or an aperture, the abnormal noise is recorded during moving image shooting. Therefore, for example, an abnormal sound inspection is performed on the lens barrel in the manufacturing process.

2. Description of the Related Art An abnormal sound inspection apparatus that performs abnormal sound determination is known in which a sound collector such as a microphone is disposed at a position slightly away from a product to be inspected (see, for example, Patent Document 1).
In the abnormal sound inspection apparatus, the obtained sound data is subjected to frequency analysis to calculate a sound pressure level in a predetermined frequency region, and the calculated sound pressure level is compared with the corrected determination value. There is known an apparatus for determining the above (for example, see Patent Document 2).

JP 2004-333199 A JP 2010-96547 A

By the way, sounds that humans feel as abnormal sounds include sounds with a large sound pressure even in a very short time, and sounds that are generated periodically even when the sound pressure is small.
Conventionally, however, such various abnormal sounds cannot be determined with high accuracy. Moreover, since the driving sound of the lens is slightly different from normal, it can give the user a sense of incongruity, so it is desirable to perform an extremely high-accuracy inspection of abnormal noise.

  An object of the present invention is to provide a lens-driven abnormal sound inspection method and a lens-driven abnormal sound inspection apparatus that can determine with high accuracy whether a lens drive sound is normal.

  The lens-driven abnormal sound inspection method of the present invention includes a first sound pressure waveform that represents the relationship between time and sound pressure, and a second sound pressure that represents the relationship between frequency and sound pressure, based on the driving sound of the lens. A waveform is created, each area of a plurality of areas obtained by dividing the first sound pressure waveform for each sound pressure value is calculated, and the first sound pressure waveform is determined by a plurality of sound pressure values. The number of crossings crossing each boundary is calculated, the area of each of a plurality of areas obtained by dividing the second sound pressure waveform for each sound pressure value is calculated, and the second sound pressure waveform Calculating the number of crossings crossing each of the plurality of boundaries defined by the value, and the area of the plurality of regions of the first sound pressure waveform and the number of crossings of the plurality of boundaries of the first sound pressure waveform The area of the plurality of regions of the second sound pressure waveform, and the plurality of boundaries of the second sound pressure waveform. And serial transverse times, based on, determines whether the drive sound of the lens is normal.

  Further, in the lens driving abnormal sound inspection method, whether or not the driving sound of the lens is normal is determined by a first feature amount that is an area of the plurality of regions of the first sound pressure waveform. , A second feature value that is the number of times of traversing the first sound pressure waveform, a third feature value that is an area of the plurality of regions of the second sound pressure waveform, and the second sound pressure. You may make it determine by MT method using the 4th feature-value which is the said frequency | count of the said crossing.

  Further, in the lens drive abnormal sound inspection method, the drive sound may be acquired by the sound collection unit in a state where the lens is attached to an imaging apparatus having a sound collection unit.

  The lens-driven abnormal sound inspection apparatus of the present invention includes a determination unit that determines whether or not the lens drive sound is normal, and the determination unit represents a relationship between time and sound pressure based on the lens drive sound. A first sound pressure waveform and a second sound pressure waveform representing the relationship between frequency and sound pressure are created, and the first sound pressure waveform is divided into a plurality of first divided sound pressure waveforms for each sound pressure value. To calculate the area of each of the plurality of first divided sound pressure waveforms, and to calculate the number of times the first sound pressure waveform crosses each of the plurality of boundaries defined by the sound pressure value. The second sound pressure waveform is divided into a plurality of second divided sound pressure waveforms for each sound pressure value, and the respective areas of the plurality of second divided sound pressure waveforms are calculated, and the second sound pressure waveform is calculated. Calculating the number of times the sound pressure waveform crosses each of the plurality of boundaries determined by the value of the sound pressure, and the plurality of the first sound pressure waveforms The area of the region, the number of crossings of the plurality of boundaries of the first sound pressure waveform, the area of the plurality of regions of the second sound pressure waveform, and the area of the second sound pressure waveform Whether the driving sound of the lens is normal is determined based on the number of times of traversing a plurality of boundaries.

  According to the present invention, it can be determined with high accuracy whether the driving sound of the lens is normal.

It is a schematic block diagram which shows the lens drive abnormal sound inspection apparatus and imaging device which concern on one embodiment of this invention. 1 is a block diagram illustrating a lens-driven abnormal sound inspection apparatus and an imaging apparatus according to an embodiment of the present invention. It is an operation | movement flowchart in one embodiment of this invention. 1 is a hardware configuration example of a computer that can operate as a lens-driven abnormal sound inspection apparatus according to an embodiment of the present invention. It is a flowchart for demonstrating the lens drive abnormal sound inspection method which concerns on one embodiment of this invention. It is a figure which shows the 1st sound pressure waveform showing the relationship between time and sound pressure in one embodiment of this invention. It is a figure which shows the 2nd sound pressure waveform showing the relationship between the frequency and sound pressure in one embodiment of this invention. It is an example of the waveform for demonstrating the area (1st and 3rd feature-value) of each area | region of the 1st and 2nd sound pressure waveform in one embodiment of this invention. It is a table | surface for demonstrating the area (1st and 3rd feature-value) of each area | region of the 1st and 2nd sound pressure waveform in one embodiment of this invention. It is an example of the waveform for demonstrating the frequency | count of crossing (2nd and 4th feature-value) of each boundary of the 1st and 2nd sound pressure waveform in one embodiment of this invention. It is a table | surface for demonstrating the frequency | count (2nd and 4th feature-value) of crossing of each boundary of the 1st and 2nd sound pressure waveform in one embodiment of this invention. It is a graph which shows the 1st and 2nd feature-value in one embodiment of this invention. It is a graph which shows the 3rd and 4th feature-value in one embodiment of this invention. It is a figure which shows the 1st sound pressure waveform (other example) showing the relationship between time and sound pressure in one embodiment of this invention. It is a figure which shows the 2nd sound pressure waveform (other example) showing the relationship between the frequency and sound pressure in one embodiment of this invention. It is a graph (other example) which shows the 1st and 2nd feature-value in one embodiment of this invention. It is a graph (other example) which shows the 3rd and 4th feature-value in one embodiment of this invention.

FIG. 1 is a schematic configuration diagram illustrating a lens driving abnormal sound inspection apparatus 1 and an imaging apparatus 10 according to an embodiment of the present invention.
A camera lens barrel 20 that is an example of a lens that is inspected for driving sound is connected to the imaging apparatus 10 by a camera mount (not shown).

The imaging device 10 includes a storage unit 11, a control unit 12, and a sound collection unit 13. The imaging device 10 is, for example, a digital camera having a recording or recording function, another recorder, or the like.
The storage unit 11 is, for example, a memory card, and stores driving conditions and sound collection data of the camera lens frame 20 to be examined.

The control unit 12 is a microprocessor, for example, and controls the driving of the camera lens barrel 20 to be examined.
The sound collection unit 13 is, for example, a built-in microphone, and collects drive sound of the camera lens barrel 20 to be examined. The sound collection data collected in this way is stored in the storage unit 11 as described above.

  The imaging device 10 is connected to the lens driving abnormal sound inspection device 1 by a wired connection or a wireless connection such as a USB (Universal Serial Bus) cable 30, and the sound collection data stored in the storage unit 11 is used as the lens driving abnormal sound inspection device 1. Forward to.

  The lens-driven abnormal sound inspection apparatus 1 includes a determination unit 2 that determines whether the lens drive sound is normal. As will be described in detail later, the determination unit 2 analyzes sound collection data using an installed program, and determines whether the drive sound of the camera lens barrel 20 is acceptable.

FIG. 2 is a block diagram showing the lens-driven abnormal sound inspection apparatus 1 and the imaging apparatus 10 according to an embodiment of the present invention.
FIG. 3 is an operation flowchart in the present embodiment.

First, in the imaging apparatus 10, driving conditions such as an AF (Autofocus) lens, an electric zoom, and an aperture that are stored in advance in the storage unit 11 are transferred to the control unit 12 (step S1).
The control unit 12 sends a control signal to the camera lens frame 20 to be tested based on the set drive condition (step S2).

The camera lens frame 20 to be tested performs AF lens driving, electric zoom driving, aperture driving, and the like based on the control signal (step S3).
The drive sound of the camera lens barrel 20 to be examined is transmitted to the imaging device 10 and collected by the sound collection unit 13 (step S4).

The collected sound collection data is stored in the storage unit 11 (step S5).
The drive sound memorize | stored in the memory | storage part 11 is transferred to the lens drive abnormal sound test | inspection apparatus 1 (step S6).

  Based on a program installed in the lens-driven abnormal sound inspection device 1, the determination unit 2 of the lens-driven abnormal sound inspection device 1 extracts a plurality of feature amounts of the drive sound (step S7), and the drive sound is normal. Is determined (step S8). The determination of the driving sound will be described later.

FIG. 4 is a hardware configuration example of a computer 100 that can operate as the lens driving abnormal sound inspection apparatus 1 according to the embodiment of the present invention.
A computer 100 illustrated in FIG. 4 includes a CPU (Central Processing Unit) 101, a storage unit 102, an input unit 103, a display unit 104, an interface unit 105, and a recording medium driving unit 106. These components are connected via a bus line 107 and exchange various data with each other.

  The CPU 101 is an arithmetic processing unit that controls the operation of the entire computer 100. The CPU 101 reads and executes a lens driving abnormal sound inspection program to perform lens driving abnormal sound inspection processing. The CPU 101 functions as the determination unit 2 of the lens driving abnormal sound inspection device 1.

The storage unit 102 includes a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, and the like.
The ROM is a read-only semiconductor memory in which a predetermined basic control program is recorded in advance. Note that as the ROM, a memory such as a flash memory in which stored data is nonvolatile when power supply is stopped may be used.

The RAM is a semiconductor memory that can be written and read at any time and used as a working storage area as necessary when the CPU 101 executes various control programs.
The hard disk stores various control programs executed by the CPU 101 and various data.

  The input unit 103 is, for example, a keyboard device or a mouse device. When operated by a user of the computer 100, the input unit 103 acquires various input information from the user associated with the operation content, and the acquired input information is stored in the CPU 101. Send to.

The display unit 104 is a display, for example, and displays various texts and images.
The interface unit 105 manages the exchange of various information with various devices such as the imaging device 10 connected to the computer 100.

  The recording medium driving unit 106 is a device that reads various control programs and data recorded on the portable recording medium 108. The CPU 101 can read out and execute a predetermined control program recorded on the portable recording medium 108 via the recording medium driving device 106 to perform a lens driving abnormal sound inspection process.

  Examples of the portable recording medium 108 include a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), and a flash memory provided with a USB standard connector.

  In order to operate such a computer 100 as the lens-driven abnormal sound inspection device 1, first, a control program for causing the CPU 101 to perform each processing step of lens-driven abnormal sound inspection as shown in FIG. The The created control program is stored in advance in the hard disk device of the storage unit 102 or the portable recording medium 107. Then, when a predetermined instruction is given to the CPU 101, the control program is read and executed. As a result, the computer 100 operates as the lens driving abnormal sound inspection apparatus 1.

FIG. 5 is a flowchart for explaining the lens driving abnormal sound inspection method according to the embodiment of the present invention.
FIG. 6 is a diagram showing a first sound pressure waveform representing the relationship between time and sound pressure in one embodiment of the present invention.

FIG. 7 is a diagram showing a second sound pressure waveform representing the relationship between frequency and sound pressure in the present embodiment.
The processing described below is performed by the determination unit 2 (CPU 101) of the lens-driven abnormal sound inspection device 1 unless otherwise specified.

First, based on the driving sound of the lens, the first sound pressure waveform shown in FIG. 6 and the second sound pressure waveform shown in FIG. 7 are created (step S11).
The first sound pressure waveform shown in FIG. 6 is created from sound collection data of the drive sound of the camera lens barrel 20 collected by the sound collection unit 13 shown in FIGS. 1 and 2.

The first sound pressure waveform is converted into a sound pressure waveform with the horizontal axis representing the drive time and the vertical axis representing the average sound pressure in the audible frequency band.
The sound pressure in the audible frequency band is converted to a sound pressure in which a weight is applied to the audible frequency band by applying a filter of A characteristic to the sound pressure waveform in the entire frequency band.

The second sound pressure waveform shown in FIG. 7 is a waveform obtained by, for example, Fourier transforming the first sound pressure waveform shown in FIG. 6 and converting the horizontal axis to frequency and the vertical axis to amplitude (sound pressure).
Next, the respective areas (first feature amounts) of the plurality of regions S1 to S6 obtained by dividing the first sound pressure waveform shown in FIG. 6 for each sound pressure value are calculated (step S12).

  Each area | region S1-S6 is each area | region when dividing | segmenting a vertical axis | shaft in the fixed narrow range. As an example different from FIG. 6, when the waveform is “sample1” shown in FIG. 8A, the area is 150 in the region S1, 120 in the region S2, and 120 in the region S3 in order from the bottom as shown in FIG. 8B. 50, the region S4 is 25, the region S5 is 8, and the region S6 is 1.

  8A and 8B are for explaining in common the calculation method of the first feature amount (areas of the regions S1 to S6) and a third feature amount (areas of the regions FS1 to FS6) described later. In this case, the areas of the first feature quantity and the third feature quantity do not match.

Next, the number of times of traversing (second feature amount) the first sound pressure waveform shown in FIG. 6 crosses each of a plurality of boundaries determined by the sound pressure value is calculated (step S13).
The number of crossings is the number of times that the waveform crosses the respective boundaries C1 to C6 when the vertical axis is divided in a certain narrow range. In the present embodiment, the boundaries between the regions S1 to S6 are the boundaries C1 to C5.

  When the waveform is “sample 1”, as shown in FIG. 9B, the number of crossings is as follows from the bottom: 0 for boundary C1, 9 for boundary C2, 12 for boundary C3, 10 for boundary C4, 10 for boundary C5, and boundary C6 Becomes 4.

  9A and 9B are for explaining in common the calculation method of the second feature quantity (the number of crossings of the boundaries C1 to C6) and a fourth feature quantity (the number of crossings of the boundaries FC1 to FC6) described later. However, the number of times of traversing the second feature value and the fourth feature value is not the same.

  Similar to the first sound pressure waveform, for the second sound pressure waveform shown in FIG. 7, the areas (third feature amounts) of the regions FS1 to FS6 are calculated (step S14), and each boundary FC1 is calculated. The number of crossings of FC6 (fourth feature amount) is calculated (step S15).

  As described above, the first to fourth feature amounts calculated for the first sound pressure waveform shown in FIG. 6 and the second sound pressure waveform shown in FIG. 7 are expressed as shown in FIGS. 10A and 10B. The Based on these first to fourth feature amounts, it is determined whether the driving sound of the lens is normal (step S16). Note that the lens 1 and the lens 2 are non-defective products, and the lens 3 is a defective product.

For example, the driving sound of the defective lens 3 generates an abnormal sound that is low in sound pressure but feels harsh to humans.
By using the MT (Mahalanobis Taguchi) method, the MD (Mahalanobis Distance) value shown in FIG. 10A can be calculated from the first and second feature quantities. Further, the MD value shown in FIG. 10B can be calculated from the third and fourth feature amounts.

  The MD value can be calculated by a known method (for example, “a well-understood MT system, a new technology for pattern recognition by quality engineering” (written by Tamura Kishiomi, Japan Standards Association, 2009, pages 42-45)). .

  For example, when the MD value is smaller than a predetermined threshold, it can be determined that the driving sound is normal, and when the MD value is larger than the threshold, it can be determined that the driving sound is abnormal. Note that the threshold value may be determined with reference to the MD value of a lens that has been inspected for abnormal noise with the human ear at the initial stage of lens production or production and determined to be defective.

  For example, as shown in FIG. 10A, the MD values calculated based on the first and second feature amounts are not greatly different in all the lenses 1 to 3. When the MD values of these lenses 1 to 3 are equal to or less than the threshold value, it is determined that the lens 3 is a non-defective product, and it cannot be determined that the lens 3 is a defective product.

  On the other hand, as shown in FIG. 10B, the MD value calculated by the third and fourth feature amounts is larger only than the lens 3 alone. For example, when the MD value of the lens 3 is larger than the threshold value, it can be determined that the lens 3 is defective.

  In the case of the second sound pressure waveform illustrated in FIG. 7, the difference A illustrated in FIG. 7 is generated for the lens 3, thereby generating a difference B in the third feature amount (area of the region FS <b> 1) illustrated in FIG. 10B. As a result, only the lens 3 has a larger value of 3.61 than the other, and can be determined to be abnormal.

Hereinafter, another example in which the defective lens 3 is replaced with another lens 4 will be described.
FIG. 11 is a diagram showing a first sound pressure waveform (another example) representing the relationship between time and sound pressure in one embodiment of the present invention.

FIG. 12 is a diagram illustrating a second sound pressure waveform (another example) representing the relationship between the frequency and the sound pressure in the present embodiment.
For example, in the driving sound of the defective lens 4, sudden abnormal noise is generated in a very short time.

In the second sound pressure waveform shown in FIG. 12, no significant difference appears in the third and fourth feature amounts and the MD value as shown in FIG. 13B, so it is determined that the driving sound of the lens 4 is normal. Can be done.
On the other hand, in the first sound pressure waveform shown in FIG. 11, the difference C occurs in the lens 4, thereby causing the difference D in the first feature amount (area of the region S <b> 6) shown in FIG. A difference E occurs in the feature amount (number of crossings of the boundary C). As a result, the MD value has a large value of 4.84 only for the lens 4 and can be determined to be abnormal.

  In the present embodiment described above, the area of each region (first feature value) obtained from the first sound pressure waveform, the number of times of crossing each boundary (second feature value), and the second sound pressure waveform. Based on the area (third feature value) of each region and the number of times of traversing each boundary (fourth feature value), whether or not the lens driving sound is normal is determined.

  Therefore, by using the area (first feature amount) of each region of the first sound pressure waveform and the number of times of crossing each boundary (second feature amount), for example, it is relatively large in a very short time during the drive time. It is possible to determine an abnormal sound in which sound pressure is generated with high accuracy. Further, by using the area (third feature amount) of each region of the second sound pressure waveform and the number of times of crossing each boundary (fourth feature amount), for example, an abnormal sound generated only at a specific frequency, that is, Even if the sound pressure is small, it is possible to determine with high accuracy a sound that feels harsh to the human ear.

  Therefore, according to the present embodiment, it can be determined with high accuracy whether the driving sound of the lens is normal.

  In the present embodiment, it is determined whether the drive sound is normal by the MT method using the first to fourth feature amounts. Therefore, it can be determined with higher accuracy whether the driving sound of the lens is normal.

  Further, in the present embodiment, the sound collection unit 13 acquires the drive sound in a state where the camera lens frame (an example of a lens) is attached to the imaging device 10 having the sound collection unit 13. Therefore, it is possible to detect the lens driving sound that is recorded during moving image shooting in a form close to the actual use state, and to determine whether the lens driving sound is normal or not with higher accuracy. Furthermore, the capital investment for the sound collection device can be reduced. Note that when sound is picked up inside the imaging apparatus 10, the sound that is picked up becomes the sound at the time of moving image shooting. However, when collecting sound outside the imaging apparatus 10, the sound is not necessarily the same as the sound collected inside the imaging apparatus 10 through the lens (the camera lens frame 20 to be tested).

  In the present embodiment, it is possible to determine the MD value using the first to fourth feature values with very high accuracy. For example, the first to fourth feature values are determined. It is also possible to determine abnormal noise with high accuracy by calculating the sum of differences from those predetermined reference values. Therefore, you may determine abnormal noise using the 1st-4th feature-value by methods other than calculation of MD value.

  In this embodiment, since the sound collection unit 13 is arranged inside the imaging device 10, it is possible to determine abnormal noise with very high accuracy and reduce capital investment. However, the sound collection device is a lens. Even if it is arranged separately, it is possible to determine abnormal noise with high accuracy.

DESCRIPTION OF SYMBOLS 1 Lens drive abnormal sound inspection apparatus 2 Judgment part 10 Imaging apparatus 11 Memory | storage part 12 Control part 13 Sound collection part 20 Camera lens frame 30 USB cable 100 Computer 101 CPU
DESCRIPTION OF SYMBOLS 102 Storage part 103 Input part 104 Display part 105 Interface part 106 Recording medium drive part 107 Bus line 108 Portable recording medium

Claims (4)

Thereby creating a first sound pressure waveform representing the relation between the time between the sound pressure based on the drive sound of the lens, obtained by Fourier transforming the first sound pressure waveform, the relationship between the frequency and sound pressure Create a second sound pressure waveform that represents
Calculating an area of each of a plurality of regions obtained by dividing the first sound pressure waveform for each sound pressure value of the first sound pressure waveform ;
Calculating the number of times that the first sound pressure waveform crosses each of a plurality of boundaries determined by the sound pressure value of the first sound pressure waveform ;
Calculating the area of each of a plurality of regions obtained by dividing the second sound pressure waveform for each sound pressure value of the second sound pressure waveform ;
Calculating the number of times that the second sound pressure waveform crosses each of a plurality of boundaries determined by the sound pressure value of the second sound pressure waveform ;
The area of the plurality of regions of the first sound pressure waveform, the number of crossings of the plurality of boundaries of the first sound pressure waveform, and the area of the plurality of regions of the second sound pressure waveform And a lens driving abnormal sound inspection method for determining whether the driving sound of the lens is normal based on the number of crossings of the plurality of boundaries of the second sound pressure waveform. It is determined whether the driving sound of the lens is normal.
A first feature amount that is an area of the plurality of regions of the first sound pressure waveform;
A second feature amount that is the number of crossings of the first sound pressure waveform;
A third feature amount that is an area of the plurality of regions of the second sound pressure waveform;
The lens-driven abnormal sound inspection method according to claim 1, wherein the determination is made by an MT method using the fourth feature amount that is the number of times of traversing the second sound pressure waveform.   The lens drive abnormal sound inspection method according to claim 1, wherein the drive sound is acquired by the sound collection unit in a state where the lens is attached to an imaging apparatus having a sound collection unit. A determination unit for determining whether the driving sound of the lens is normal;
The determination unit
Thereby creating a first sound pressure waveform representing the relation between the time between the sound pressure based on the drive sound of the lens, obtained by Fourier transforming the first sound pressure waveform, the relationship between the frequency and sound pressure Create a second sound pressure waveform that represents
The area of each of said first sound pressure waveform first divided into a plurality of first split sound pressure waveforms of the plurality for each value of the first sound pressure waveform of the sound pressure of the split sound pressure waveform Calculate
Calculating the number of times that the first sound pressure waveform crosses each of a plurality of boundaries determined by the sound pressure value of the first sound pressure waveform ;
The area of each of said second sound pressure waveform a second is divided into a plurality of second divided sound pressure waveform for each value of the second sound pressure waveform of the sound pressure of the plurality of divided sound pressure waveform Calculate
Calculating the number of times that the second sound pressure waveform crosses each of a plurality of boundaries determined by the sound pressure value of the second sound pressure waveform ;
The area of the plurality of regions of the first sound pressure waveform, the number of crossings of the plurality of boundaries of the first sound pressure waveform, and the area of the plurality of regions of the second sound pressure waveform And a lens-driven abnormal sound inspection device that determines whether the driving sound of the lens is normal based on the number of crossings of the plurality of boundaries of the second sound pressure waveform.

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