JP2006098095A - Moisture content-measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture content-measuring instrument capable of obtaining a visible image by one exposure without requiring the changeover of a filter and capable of measuring moisture content. <P>SOLUTION: The moisture content-measuring instrument is equipped with a CCD camera 1 having sensitivity up to a near infrared region, the near infrared light cutting filter provided to the valid pixel region of the CCD imaging element of the CCD camera 1 and a visible light cutting filter provided to the invalid pixel region of the CCD imaging element of the CCD camera 1. The image of the valid pixel region photographed by the CCD camera 1 is displayed on a display device 4 and moisture content is calculated on the basis of the output from the imaging element of the invalid region is calculated by a controller 3 and the calculation result is displayed on a display device 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a moisture content measuring apparatus for measuring the moisture content contained in skin or the like.

  In selecting cosmetics and pharmaceuticals, it is an important factor to grasp the moisture content contained in the skin. Therefore, in order to measure the moisture content of the skin, conventionally, a method for measuring high-frequency impedance, a method for measuring microwave conductivity, and the like are known.

  However, the above-described measurement method has a problem that it is necessary to perform measurement by bringing an electrode or the like into contact with the skin, and the measurement work is troublesome.

  Also, when measuring the moisture content of the skin, such as when selling cosmetics, if the moisture content of the skin along with the skin condition can be displayed, it is convenient for the user to check the condition.

  The applicants have already taken a CCD camera, a visible light transmission filter, and an infrared light transmission filter, and the CCD camera lens was photographed in the first state covered with the visible light transmission filter. Based on the image data of the visible light image and the image data of the infrared light image taken by the CCD camera in the second state where the lens of the CCD camera is covered with the infrared light transmission filter, the water content of the measurement area is determined. A water content measuring device for calculating the distribution has been proposed (see Patent Document 1).

And it can comprise so that a user may recognize distribution of the moisture content of a measurement area by connecting this apparatus to a CRT display using the said moisture content measuring device.
JP 2002-98633 A

  However, in the apparatus described in Patent Document 1 described above, a mechanism unit for switching between a visible light transmission filter and an infrared transmission filter is necessary, and a visible light image and a near infrared image are captured by switching the filter. In addition, at least two exposures are required, and it is difficult to display the state in real time.

  This invention makes it a subject to provide the moisture content measuring apparatus which can measure a moisture content while obtaining a visible image by one exposure, without requiring the switch of a filter.

  The present invention relates to a CCD camera having sensitivity up to the near-infrared region, and a pass-band in the wavelength region of near-infrared light provided in a non-effective pixel region of the CCD image pickup device of this CCD camera and the wavelength region of visible light And a processing unit that calculates a water content based on an output from the imaging device in the non-effective region.

  In the present invention, the effective pixel region of the CCD image pickup device of the CCD camera is provided with a second filter having a pass-stop band in the near-infrared light wavelength region and a pass-band in the visible light wavelength region, An image of the effective pixel area imaged by the CCD camera is displayed on the display device, and the moisture content is calculated based on the output from the imaging device in the non-effective area by the calculation means, and the result is displayed on the display device. Can be configured.

  According to the present invention described above, the pixel distribution of the pixel area of the CCD camera can be used effectively, and the image data can be used separately for the moisture content measurement and for the display. Detection can be performed, and real-time display and moisture content can be easily detected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a moisture content measuring apparatus according to an embodiment of the present invention.

  The water content measuring device according to the present invention includes a high sensitivity CCD camera 1 having sensitivity up to the near infrared region. As shown in the sensitivity characteristic diagram of FIG. 5, the CCD camera 1 has a sensitivity up to the near infrared region as compared with the conventional CCD camera, and has a sensitivity up to a water absorption wavelength peripheral band of 900 nm to 1200 nm. The water content can be detected by detecting the change in the amount of light in this band. FIG. 4 is a diagram showing the relationship between the reflectance (%) and the incident wavelength (nm). FIG. 4 shows that the absorption wavelengths of water are 1.45 μm and 1.95 μm, but the peripheral wavelength band also changes as the water content increases. Therefore, if the CCD camera 1 having sensitivity up to the near infrared region is used, the water content can be detected.

  As shown in FIG. 2, in the CCD camera 1, the CCD image pickup element forms a pixel region 10 by arranging a plurality of light receiving elements in an area. As described above, each pixel is composed of a high-sensitivity CCD having sensitivity up to the water absorption wavelength peripheral band of 900 nm to 1200 nm.

  Normally, the CCD camera 1 does not use all information captured by the CCD element as an image, and some peripheral pixel data is not used as image data used for a display device or the like. For this reason, the pixel region 10 of the CCD camera 1 is composed of an effective pixel region 12 and a surrounding non-effective pixel region 11, and each pixel in both pixel regions is composed of a sensor having the same sensitivity. The water content measuring apparatus of the present invention makes good use of the pixel distribution of the pixel area 10 of the CCD camera 1 and uses image data separately for water content measurement and display.

  For this reason, on the effective pixel region 12 used as display image data, a near-infrared cut filter having a pass-stop band in the near-infrared light wavelength region and a pass-band in the visible light wavelength region is provided. A visible light cut filter having a pass band in the near-infrared light wavelength region and a pass-inhibiting band in the visible light wavelength region is provided on the non-effective pixel region 11 used as data for water content measurement. Yes. When it is necessary to measure the image and water content in real time like the skin water content, as described above, an optical filter having different transmission characteristics on the front surface of the light receiving unit of the CCD of the high sensitivity CCD camera 1, that is, If a near-infrared cut filter is provided on the effective pixel region 12 and a visible light cut filter is provided on the non-effective pixel region 11, an image is picked up in the central effective pixel region 12, and the water content in the peripheral pixels Can be detected.

  Although the CCD camera 1 can capture an image using natural light such as sunlight, in this embodiment, the CCD camera 1 includes a light source in order to ensure the accuracy of moisture content measurement. This light source uses a light bulb having a broadband spectral characteristic from the visible light region to the near infrared region. FIG. 6 shows an example of an emission spectrum of a halogen bulb that can be used as a light source. FIG. 6 shows the spectral characteristics when the electric power of the bulb is constant.

  As shown in FIG. 3A, a part of the palm (area surrounded by a square in the figure) is photographed by the CCD camera 1 with one exposure. In this exposure, the lens of the CCD camera 1 is photographed as close to the palm as possible in order to reduce noise such as natural light. At this time, the palm is irradiated with light from a lamp provided in the CCD camera 1, and the reflected light is guided to the pixel region 10 in the CCD camera 1. Then, as shown in FIG. 5B, the pixel area 10 is given display image data by visible light that has passed through the near-infrared cut filter to the effective pixel area 12, and the non-effective pixel area 11 is visible. Image data for water content detection that has passed through the light cut filter is provided.

  All the image data of the non-effective pixel area 11 and the effective pixel area 12 imaged by the CCD camera 1 are given to the memory 2 and stored therein. The image data stored in the memory 2 is taken into the controller 3 under the control of the controller 3, and a predetermined process is performed. The controller 3 is constituted by a microprocessor or the like, and includes a memory in which a program for controlling operations is written, a work memory for capturing image data, and the like. These memories may be provided inside or outside the controller 3 and are appropriately selected as necessary.

  The controller 3 is an image of the non-effective pixel region 11 in which the wavelength of the visible light region is cut by the visible light cut filter among the image data captured by the CCD camera 1 for detecting the water content, and the near infrared region wavelength is received. The data is taken in, and the water content is calculated based on the image data as described later.

  Further, the controller 3 takes in the image data of visible light transmitted through the near-infrared cut filter received by the effective pixel region 12 in order to display the captured image on the display device 4 constituted by a CRT, a liquid crystal display device, or the like. To the display device 4. On the display device 4, an image of the effective pixel region 12 captured by the CCD camera 1 is displayed. Further, the display device 4 is configured to display the measured water content by superimposing or dividing the image area of the display device 4.

  Next, an example of a method for calculating the water content will be described. In the present invention, the controller 3 calculates the water content using a water content calculation formula corresponding to the measurement object. For this reason, the controller 3 stores calculation formula data as described later.

  As described above, since the water content calculation formula corresponding to the measurement target is used, the teaching data is measured for each measurement target, and the water content calculation formula is obtained from the measurement data by multiple regression. In general, quantitative analysis using near-infrared light in a multi-wavelength band can be expressed as follows using a multiple regression equation.

C = K ₀ + K ₁ × log (1 / R ₁ )
+ K ₂ × log (1 / R ₂ )
+ K ₃ × log (1 / R ₃ )
+ ...
+ K _n × log (1 / R _n )
Here, C is the water content, K _n is a constant obtained by multiple regression, log (1 / R _n ) is the absorbance in the measurement wavelength band, and R _n is the reflectance in the measurement wavelength band.

  In the present invention, since the wavelength band to be used is only one band of about 900 nm to 1200 nm, the above formula is as follows.

C = K ₀ + K ₁ × log (1 / R ₁ )
Here, C is the water content, K ₀ and K ₁ are constants obtained by multiple regression, log (1 / R ₁ ) is the absorbance in the 900 nm to 1200 nm band, and R ₁ is the reflectance in the 900 nm to 1200 nm band.

  The absorbance is calculated from the reflectance at the time of measuring the finger data with the known moisture content, a constant is determined in a multiple regression manner from the relationship between the moisture content and the absorbance, and the formula for calculating the moisture content is obtained. Store in.

  In addition, the reflectance calculation method can derive | lead-out a reflectance with a simple formula from an actual measurement value by measuring the standard reflecting plate which has a known reflectance beforehand. For example, when the reflectance of the actual measurement value is obtained using a standard reflector having a reflectance of 95% and 5%, the following equation is obtained.

R = 0.05 + (0.95-0.05) × (Data-DB) / (DW-DB)
Here, R is the reflectance of the object, Data is the object measurement data, DB is the standard reflector measurement data with a reflectance of 5%, and DW is the measurement data of the standard reflector with a reflectance of 95%.

  The water content can be calculated from the reflectance thus calculated by applying the above multiple regression equation.

  In the present invention, since the water content calculation formula can be expressed by a simple primary formula, depending on the measurement object, a conversion table between the object measurement data and the water content is created and the table is stored in the memory. Thus, the water content can be easily measured.

  Next, a method for measuring the moisture content of the skin using the moisture content measuring device according to the present invention will be described with reference to FIGS. The example shown in FIGS. 7 and 8 shows a case in which the measured representative moisture content of the skin is displayed.

  As shown in FIGS. 7 and 8, a part of the palm (area surrounded by a square in the figure) is photographed by the CCD camera 1 with one exposure (see FIG. 7A). In this exposure, the lens of the CCD camera 1 is photographed as close to the palm as possible in order to reduce noise such as natural light. At this time, the palm is irradiated with light from a lamp provided in the CCD camera 1, and the reflected light is guided to the pixel region 10 in the CCD camera 1. Then, as shown in FIG. 7B, the pixel area 10 is given display image data by visible light that has passed through the near-infrared cut filter to the effective pixel area 12, and the non-effective pixel area 11 has visible light. Image data for water content detection that has passed through the light cut filter is given, and all image data including valid and invalid are stored in the memory 2 (step S1). Then, the controller 3 extracts near-infrared light receiving pixel data from the non-effective pixel region 11 that has passed through the visible light cut filter from the memory 2 (step S2). In addition, the controller 3 controls the display device 4 to display an image based on the image data, that is, an image of the palm portion in the effective pixel area 12.

  Subsequently, the controller 3 calculates the water content for each near-infrared light receiving pixel data based on the reflectance calculated and stored in advance and the above-described calculation formula (step S3). Then, the controller 3 calculates a statistical value such as an average value from the calculated water content data for each pixel (step S4). In this example, the average water content is obtained from the average value of all the pixel data, and the maximum value data with the largest water content and the minimum value data with the smallest water content are obtained. Then, as shown in FIG. 7C, whether each data of the visible image and the water content statistical value is displayed together on the display screen 40 of the display device 4 (step S5), and the water content measurement operation is terminated. If it is not determined (step S6) and the process does not end, the process returns to step S1 to repeat the above-described operation.

  Next, another method for measuring the moisture content of the skin using the moisture content measuring device according to the present invention will be described with reference to FIG. 9 and FIG. The example shown in FIGS. 9 and 10 shows a case where the distribution of the measured moisture content of the skin is calculated and displayed.

  As shown in FIGS. 9 and 10, a part of the palm (area surrounded by a square in the figure) is photographed by the CCD camera 1 with one exposure (see FIG. 9A). In this exposure, the lens of the CCD camera 1 is photographed as close to the palm as possible in order to reduce noise such as natural light. At this time, the palm is irradiated with light from a lamp provided in the CCD camera 1, and the reflected light is guided to the pixel region 10 in the CCD camera 1. Then, as shown in FIG. 9B, the pixel area 10 is given display image data by visible light that has passed through the near-infrared cut filter to the effective pixel area 12, and the non-effective pixel area 11 is visible. Image data for water content detection that has passed through the light cut filter is given, and all image data including valid and invalid are stored in the memory 2 (step S11). Then, the controller 3 extracts near-infrared light receiving pixel data from the non-effective pixel region 11 that has passed through the visible light cut filter from the memory 2 (step S12). In addition, the controller 3 controls the display device 4 to display an image based on the image data, that is, an image of the palm portion in the effective pixel area 12.

  Subsequently, the controller 3 calculates the water content for each near-infrared light receiving pixel data based on the reflectance calculated and stored in advance and the above-described calculation formula (step S13). Then, the controller 3 obtains the maximum value data with the largest water content and the minimum value data with the smallest water content and the pixel position from the calculated water content data for each pixel (step S14).

  In the case of skin or the like, since the photographing range is narrow, there is no problem even if the water content distribution inclination direction is regarded as one direction. As shown in FIG. 9C, in the case where the upper right pixel portion has the maximum water content and the pixel portion located diagonally to the lower left of the pixel portion has the minimum water content, as shown in FIG. It can be considered that the water content is changing. Therefore, the controller 3 determines the water content distribution inclination direction from the positions of the maximum water content pixel and the minimum water content pixel (step S15). Subsequently, using the water content data around the visible image, the water content corresponding to the visible image is calculated by linear interpolation in the water content distribution inclination direction (step S16).

  Thereafter, a water content distribution map is created from the water content corresponding to the calculated visible image pixel (step S17). Then, the generated moisture content distribution map and the visible image are displayed together (step S18), and it is determined whether or not to end the moisture content measurement operation (step S19). If not, the process returns to step S11. The above operation is repeated. In addition, you may comprise so that the moisture content of a representative position may be displayed with a moisture content distribution map.

  As described above, the moisture content measuring apparatus of the present invention provides a visible light cut filter in the non-effective pixel data portion that is normally excluded without switching the filter, and performs moisture measurement using the pixel data in this region. Therefore, a visible image and moisture measurement can be performed with one photographing, and real-time moisture measurement can be performed while monitoring with a display device.

  In the above-described embodiment, the case where the moisture content of the skin is measured has been described. However, the present invention is not limited to the moisture content of the skin, and any object that can be imaged with a CCD camera, such as the moisture content of the ground surface. The water content of the product can be measured.

It is a block diagram which shows the structure of the moisture content measuring apparatus concerning embodiment of this invention. It is a schematic diagram which shows the pixel area | region of the image pick-up element part of the CCD camera used for this invention. It is a model diagram which shows the relationship between imaging | photography of the moisture content measuring device concerning embodiment of this invention, and the pixel area of a CCD camera. It is a characteristic view which shows the relationship between a reflectance (%) and incident wavelength (nm). It is a figure which shows the sensitivity characteristic of a CCD camera. It is a characteristic view which shows the example of the emission spectrum of the halogen bulb which can be used as a light source. It is a schematic diagram which shows the case where the moisture content of skin is measured and the representative moisture content of skin is displayed. It is a flowchart which shows operation | movement in the case of measuring the moisture content of skin and displaying the representative moisture content of skin. It is a schematic diagram which shows the case where the moisture content of skin is measured and the distribution moisture content of skin is displayed. It is a flowchart which shows operation | movement in the case of measuring the moisture content of skin and displaying the distribution moisture content of skin.

Explanation of symbols

1 CCD camera 2 Memory 3 Controller 4 Display device

Claims (2)

CCD camera having sensitivity up to the near-infrared region, and a pass-band in the near-infrared light wavelength region provided in the non-effective pixel region of the CCD image sensor of this CCD camera, and a pass-inhibiting band in the visible light wavelength region A water content measuring device comprising: a filter having a calculation function; and a processing means for calculating a water content based on an output from the imaging device in the non-effective region. An effective pixel area of the CCD image pickup device of the CCD camera is provided with a second filter having a pass blocking band in the near-infrared light wavelength band and a pass band in the visible light wavelength band. 2. An image of a pixel region is displayed on a display device, the moisture content is calculated based on an output from an imaging device in an invalid effective region by the calculation means, and the result is displayed on the display device. The moisture content measuring device according to 1.

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