JP2014079508A - Dimming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimming device capable of appropriately adjusting illumination.SOLUTION: The dimming device includes: an imaging part 23 that has a plurality of pixels for receiving light and photoelectrically converting the light into an electrical signal; a light emission part 22 that emits illumination light illuminating an area including an imaging area of the imaging part 23; a correction part 21a that corrects an output value which is output from a saturation pixel and has reached a set upper limit, out of a plurality of output values to be output from the plurality of pixels on the basis of the electrical signal; a calculation part 21b that calculates a photometric value being an average of the corrected output value corrected by the correction part 21a and the output values to be output by the pixels other than the saturation pixel, on the basis of the corrected output value and the output values; and a dimming part 21c that controls an operation of the light emission part 22 on the basis of the photometric value calculated by the calculation part 21b.

Description

  The present invention relates to a light control device that is introduced into, for example, a subject and performs light control of illumination light when an image in the subject is captured.

  2. Description of the Related Art Conventionally, endoscopes are widely used as medical observation apparatuses that are introduced into the body of a subject such as a patient and observe the inside of the body. In recent years, swallowable endoscopes (capsule endoscopes) that include an imaging device and a communication device that wirelessly transmits image data captured by the imaging device inside a capsule-type housing have been developed. ing. Capsule endoscopes are used for peristaltic movement inside organs such as the esophagus, stomach, and small intestine after being swallowed from the subject's mouth for observation inside the body and before being spontaneously discharged from the subject. Therefore, it has a function of moving and sequentially imaging.

  While moving inside the body, image data imaged inside the body by the capsule endoscope is sequentially transmitted outside the body by wireless communication, and stored in a memory provided inside or outside the receiving apparatus outside the body. The doctor or nurse can take the image data stored in the memory into the information processing apparatus and make a diagnosis based on the image displayed on the display of the information processing apparatus.

  By the way, in the capsule endoscope, in addition to a solid-state imaging device such as a CCD sensor or a CMOS sensor as an imaging device for imaging an inside of a living body, an illumination unit such as an LED that illuminates an imaging region by the imaging device, An optical system such as an optical lens is provided. The solid-state imaging device receives light incident on each pixel from the imaging region and outputs a luminance value of the received light. In a conventional capsule endoscope, the light emission time and light emission intensity of an LED or the like are adjusted based on a photometric value that is an average value of luminance values of light received by each pixel of a solid-state imaging device.

  Here, as shown in FIG. 10, in the captured image P (imaging region), a halation region H that emits light (output luminance value) with brightness greater than the upper limit (upper limit value) of the set output luminance value of the pixel. May exist. When each pixel of the solid-state imaging device receives light brighter than the upper limit value, the upper limit value is output as a luminance value. That is, when light exceeding the upper limit value is continuously received in each pixel, the upper limit value that is smaller than the actually received value is output from the pixel as the luminance value. Hereinafter, a pixel that receives light having a brightness that is equal to or higher than the upper limit value is referred to as a saturated pixel.

FIG. 11A is a graph showing an example of the relationship between the amount of light obtained by a conventional solid-state imaging device and the photometric value, and FIG. 11B is a graph showing the relationship between the amount of light and the number of saturated pixels. . The light quantity Q ₁ is a light quantity in which all pixels are saturated pixels among the target pixels for calculating the photometric value, and the saturated pixel number Max is a case where all the target pixels for calculating the photometric value are saturated pixels. Is shown. As shown in FIGS. 11A and 11B, when the amount of light applied to the solid-state image sensor increases and a saturated pixel is generated (see FIG. 11B), the solid-state image sensor is calculated from the output. photometric value is different from the ideal (in the absence of the upper limit of the luminance value) the photometric value of the output light amount straight line L ₀ which is calculated from the amount of light is output as a low value (FIG. 11 (a)). Further, the number of saturated pixels is increased in accordance with the amount of light to be irradiated is increased, the photometric value output curve L ₁ obtained for the actual quantity, the greater the difference between the output light intensity linearly L _0. When all the pixels are saturated pixels, the photometric value is output as a constant value (total number of pixels × upper limit value) regardless of the brightness of light received between the pixels.

  As described above, the photometric value used for adjusting the illumination is smaller than the value that should be calculated from the actual light amount due to the occurrence of the saturated pixel. In some cases, the emission intensity did not correspond to the actual light amount. Thereby, for example, in the adjustment of the light emission intensity, the light emission intensity is reduced at a reduction rate smaller than the reduction rate that should be originally reduced, and the halation region H in the captured image P remains present in the subsequent imaging. End up.

In response to the above-described problem, the presence or absence of a saturated pixel is determined, and when the saturated pixel is present, a correction value is added to the photometric value, or the correction coefficient is multiplied, and the output light amount straight line L0 and the photometric _value are measured. technique for correcting the difference between the value output curve L ₁ is disclosed (e.g., see Patent documents 1 and 2).

JP 2002-085345 A JP 2006-060504 A

  However, since the techniques disclosed in Patent Documents 1 and 2 add a correction value to a photometric value or multiply a correction coefficient, a predetermined luminance value that does not reach the upper limit value is also determined. The correction value is added or the correction coefficient is multiplied. That is, luminance values that are output from pixels that are not saturated pixels before photometric value calculation and do not require correction are corrected. As a result, the photometric value obtained by appropriately correcting the luminance value output by the saturated pixel is not obtained, and as a result, there is a case where appropriate illumination adjustment cannot be performed.

  The present invention has been made in view of the above, and an object thereof is to provide a light control device capable of performing appropriate illumination adjustment.

  In order to solve the above-described problems and achieve the object, a light control device according to the present invention includes an imaging unit having a plurality of pixels that receive light and photoelectrically convert it into an electrical signal, and an imaging region of the imaging unit. An illuminating unit that emits illumination light that illuminates a region to be included, and a saturated pixel that outputs an output value that has reached a set upper limit value among a plurality of output values output from the plurality of pixels based on the electrical signal A correction unit that corrects the output value, a correction output value corrected by the correction unit, and an output value output by a pixel other than the saturated pixel, and an average value of the correction output value and the output value A calculation unit that calculates a photometric value, and a dimming unit that controls the operation of the illumination unit based on the photometric value calculated by the calculation unit.

  In the light control device according to the present invention as set forth in the invention described above, the correction unit performs correction processing according to the number of the saturated pixels.

  The light control device according to the present invention is characterized in that, in the above invention, the correction unit calculates the correction output value by adding a correction value to the output value.

  In the light control device according to the present invention as set forth in the invention described above, the correction unit calculates the correction output value by multiplying the output value by a correction coefficient.

  According to the present invention, the correction unit performs a correction process according to the luminance value based on the image signal imaged by the imaging unit, and the average value (photometric value) of each luminance value including the corrected luminance value calculated by the calculation unit. ), The light control unit controls the illumination unit, so that it is possible to perform appropriate illumination adjustment.

FIG. 1 is a schematic diagram illustrating a configuration example of an endoscope system according to the first embodiment of the present invention. FIG. 2 is a schematic diagram showing a configuration example of the capsule endoscope shown in FIG. FIG. 3 is a block diagram schematically showing a configuration example of the capsule endoscope shown in FIG. FIG. 4 is a schematic diagram showing a configuration of a main part of the capsule endoscope shown in FIG. FIG. 5 is a graph (a) showing the relationship between the light amount and the photometric value in the endoscope system according to the first embodiment of the present invention, and a graph (b) showing the relationship between the light amount and the number of saturated pixels. FIG. 6 is a block diagram schematically illustrating a configuration example of a capsule endoscope according to the second embodiment of the present invention. FIG. 7 is a graph showing the relationship between the number of saturated pixels and the correction value in the endoscope system according to the second embodiment of the present invention. FIG. 8 is a graph showing the relationship between the light amount and the photometric value in the endoscope system according to the second embodiment of the present invention. FIG. 9 is a graph showing the relationship between the number of saturated pixels and the correction coefficient in the endoscope system according to the modification of the second embodiment of the present invention. FIG. 10 is a diagram schematically illustrating an imaging region of the solid-state imaging device. FIG. 11 is a graph (a) showing the relationship between the amount of light obtained by the conventional solid-state imaging device and the photometric value, and a graph (b) showing the relationship between the amount of light and the number of saturated pixels.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment. The drawings referred to in the following description only schematically show the shape, size, and positional relationship so that the contents of the present invention can be understood. That is, the present invention is not limited only to the shape, size, and positional relationship illustrated in each drawing.

(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a configuration example of an endoscope system using a capsule endoscope as a light control device according to a first embodiment of the present invention. As shown in FIG. 1, the endoscope system according to this embodiment includes a capsule endoscope 2 that captures an in-vivo image group of a subject 1 and an image signal wirelessly transmitted by the capsule endoscope 2. A receiving device 3 for receiving, a workstation 4 for displaying an in-vivo image group captured by the capsule endoscope 2, and a portable recording for transferring data between the receiving device 3 and the workstation 4 A medium 5.

  The capsule endoscope 2 includes an illumination, an imaging unit, and a wireless communication unit inside a capsule-type housing. The capsule endoscope 2 is introduced into the organ of the subject 1 by oral ingestion or the like, and then moves inside the organ of the subject 1 by a peristaltic motion or the like while moving at a predetermined interval (for example, every 0.5 seconds). Then, in-vivo images of the subject 1 are sequentially taken. The capsule endoscope 2 irradiates the subject with illumination light such as white light inside the organ, and captures an image of the subject illuminated by the illumination light, that is, an in-vivo image of the subject 1. The capsule endoscope 2 wirelessly transmits the image signal of the in-vivo image of the subject 1 imaged in this way to the external receiving device 3 in association with the imaging time. The capsule endoscope 2 sequentially repeats the in-vivo image capturing operation and the wireless transmission operation during a period from introduction into the organ of the subject 1 until ejection from the subject 1.

  The receiving device 3 includes, for example, a plurality of receiving antennas 3a to 3h distributed on the body surface of the subject 1, and a capsule inside the subject 1 via at least one of the plurality of receiving antennas 3a to 3h. A radio signal from the mold endoscope 2 is received. The receiving device 3 extracts an image signal from the received wireless signal, and acquires image data of the in-vivo image included in the extracted image signal. When receiving the in-vivo image for one frame from the capsule endoscope 2, the receiving device 3 sequentially stores the images in the recording medium 5 inserted in advance. In addition, the receiving device 3 associates the in-vivo image capturing time, exposure time data, and the like with each image. The receiving antennas 3a to 3h of the receiving device 3 may be arranged on the body surface of the subject 1 as shown in FIG. 1 or may be arranged on a jacket worn by the subject 1. Further, the number of receiving antennas of the receiving device 3 may be one or more, and is not particularly limited to eight.

  The workstation 4 captures various data such as the in-vivo image group of the subject 1 via the recording medium 5 and displays the various data such as the captured in-vivo image group. The workstation 4 receives various data such as image data of an in-vivo image of the subject 1 by inserting the recording medium 5 removed from the receiving device 3 and taking in the storage data of the recording medium 5. The workstation 4 displays the acquired in-vivo image on the display.

  The recording medium 5 is a portable recording medium for transferring data between the receiving apparatus 3 and the workstation 4 described above. The recording medium 5 is detachable from the receiving device 3 and the workstation 4 and has a structure capable of outputting and recording data when being inserted into both. When the recording medium 5 is inserted into the receiving device 3, the in-vivo image group image-processed by the receiving device 3 and time data of each image are recorded. On the other hand, when the recording medium 5 removed from the receiving device 3 is inserted into the workstation 4, the stored data (in-vivo image group or the like) of the recording medium 5 is taken into the workstation 4.

  Next, the structure of the capsule endoscope 2 shown in FIG. 1 will be described in detail. FIG. 2 is a schematic diagram showing a configuration example of the capsule endoscope 2 shown in FIG. FIG. 3 is a block diagram schematically showing a configuration example of the capsule endoscope 2 shown in FIG.

  As shown in FIG. 2, the capsule endoscope 2 encloses each component in a case 20 in a liquid-tight manner. The case 20 is an exterior case formed to have a size that can be introduced into an organ of a subject, and an open end of a casing (cylindrical casing) 20a in which a cylindrical end is sealed is a dome-shaped casing. This is realized by closing with 20b. The cylindrical housing 20a is a colored housing that is substantially opaque to visible light. The dome-shaped housing 20b is a dome-shaped optical member that is transparent to light in a predetermined wavelength band such as visible light.

  As shown in FIG. 3, the capsule endoscope 2 includes a control unit 21, a light emitting unit 22 (illumination unit), an imaging unit 23, an image signal processing unit 24, a wireless transmission unit 25, and the capsule endoscope 2. It has a power circuit 26 and a battery 27 for supplying driving power to the components.

  The control unit 21 controls driving of each component of the capsule endoscope 2 and performs input / output control of signals in each component. Based on the image signal (electrical signal) output from the image signal processing unit 24, the control unit 21 determines whether there is a saturated pixel in each pixel, and if there is a saturated pixel, the luminance of the corresponding saturated pixel Correction is performed based on the correction unit 21a that corrects the value (output value) and outputs the corrected photometric value, the corrected luminance value corrected by the correction unit 21a, and the luminance value output by pixels other than the saturated pixels. A calculation unit 21b that calculates a luminance value and a photometric value (average luminance value) that is an average value of the luminance values, and a light emission intensity and a light emission time that the light emitting unit 22 emits light based on the photometric value calculated by the calculation unit 21b And a memory 21d for storing data such as programs, parameters, and correction data used for controlling each unit.

  The light emitting unit 22 includes an LED 22a that emits illumination light that irradiates an area including the imaging region of the imaging unit 23, and an LED drive circuit 22b that controls the driving state of the LED 22a under the control of the light control unit 21c. The light emitting element of the light emitting unit 22 is not limited to the LED 22a, and various light emitting elements can be used. Moreover, as for LED22a, the edge part on the side which emits illumination light has faced the dome shape housing | casing 20b.

  The imaging unit 23 includes an optical system (not shown) such as a lens that forms an image of reflected light from the imaging region, a CCD array 23a in which, for example, R, G, and B pixels are arranged in a matrix, and a CCD array And a CCD drive circuit 23b for controlling the drive state of 23a, and images at least a part of the region irradiated by the LED 22a. Each pixel of the CCD array 23a receives the light flux in the imaging field and photoelectrically converts it to output an image signal at an output level corresponding to the received light value. In the CCD array 23a, the surface that receives the reflected light faces the dome-shaped housing 20b.

  The image signal processing unit 24 performs predetermined signal processing on the analog image signal output from the imaging unit 23 and outputs a digital image signal to the wireless transmission unit 25. The image signal processing unit 24 is a processing circuit (not shown) that performs analog signal processing such as color balance adjustment and gamma correction on the analog image signal output from the imaging unit 23, and the analog image signal is converted into a digital image signal. A / D conversion unit 24a for converting to digital data, an amplification unit 24b for amplifying the converted digital image signal, and modulating the digital signal output from the amplification unit 24b into digital data having a predetermined number of bits, and then converting the parallel data into serial data. A P / S conversion unit 24c that converts data into data, and a synchronization signal synthesis unit 24d that synthesizes a horizontal synchronization signal and a vertical synchronization signal with the image data converted into serial data. Further, the image signal processing unit 24 includes a measurement unit 24 e that measures the luminance value in the image signal output from the imaging unit 23 and outputs the measurement result to the control unit 21. The measurement unit 24e measures the luminance value of the pixel corresponding to the image signal for each pixel of the CCD array 23a based on the image signal output from the amplification unit 24b.

  The wireless transmission unit 25 transmits the image signal output from the image signal processing unit 24 as a wireless signal. The wireless transmission unit 25 generates and transmits a wireless signal including the image signal output from the image signal processing unit 24, and transmission that outputs the wireless signal output from the transmission circuit 25a to the outside as a radio wave. And an antenna 25b.

  The control unit 21, the LED drive circuit 22b, the CCD drive circuit 23b, the image processing unit 24, and the transmission circuit 25a are provided on one or a plurality of substrates (chips) as the function execution unit 200 shown in FIG.

  4 is a schematic view showing a configuration of a main part (battery 27) of the capsule endoscope 2 shown in FIG. 2, and FIG. 4 (a) is a front view schematically showing the contact member 27c. FIG. 4B is a side view schematically showing the first battery 27a, the second battery 27b, and the contact member 27c.

  The battery 27 includes a first battery 27a and a second battery 27b. The first battery 27a and the second battery 27b have a shape in which the positive electrode surface S1 is curved, and a straight line connecting the two electrodes (centers of the positive electrode surface S1 and the negative electrode surface S2) of each battery is the capsule endoscope 2. Are arranged in the case 20 so as to be parallel to the central axis N in the longitudinal direction.

  A conductive contact member 27c is provided between the first battery 27a and the second battery 27b. The contact member 27c realizes electrical continuity between the first battery 27a and the second battery 27b.

  The contact member 27c is provided on a main body portion 271 having a substantially disc shape and one main surface of the main body portion 271, and a plurality of contact members 27c (three in the first embodiment, which are in contact with the positive electrode surface S1). ) First contact portion 272 and a second contact portion 273 provided on the other main surface of the main body portion 271 and in contact with the negative electrode surface S2 of the first battery 27b.

  The first contact portion 272 protrudes from the main surface of the main body portion 271 in a hemispherical shape or a conical shape, and makes point contact with the positive electrode surface S1 of the first battery 27a at the apex. The three first contact portions 272 are respectively provided on a circle C centered on the center (or center of gravity) D of the main body portion 271. Here, in order to stabilize the contact state with respect to the curved shape of the positive electrode surface S1 in the first battery 27a, the three first contact portions 272 are provided at positions that are rotationally symmetric with respect to the center D at equal intervals. It is preferable. The main body 271 is preferably provided at a position where the central axis N of the capsule endoscope 2 passes through the center D.

  The second contact portion 273 protrudes in a hemispherical shape or a conical shape from the main surface of the main body portion 271, and makes point contact with the negative electrode surface S2 of the second battery 27b at the apex. The second contact portion 273 is provided at the central portion of the main surface of the main body portion 271 and has a hemispherical shape or a conical shape with an axis passing through the center (or center of gravity) D of the main body portion 271 as the central axis.

  According to the contact member 27c described above, even when the positive electrode surface S1 of the first battery 27a and the second battery 27b is deformed due to the operation of the capsule endoscope 2, it is curved by the three first contact portions 272. By maintaining the point contact with the positive electrode surface S1 having a shape, it is possible to maintain a stable contact state between the first battery 27a and the contact member 27c.

  In addition, electrical continuity is ensured between the first battery 27 a and the function execution unit 200 when the negative electrode of the first battery 27 a contacts the pressing member 28 fixed to the function execution unit 200. The pressing member 28 is realized by a conductive leaf spring, for example.

  In the capsule endoscope 2, a pre-exposure process is performed before the main exposure process for image acquisition in a frame period set for acquiring one image, and some of the plurality of pixels By using the output result for the pre-exposure, and setting the brightness parameters (such as the light emission intensity and the light emission time of the LED 22a) of the image acquired during the frame period, it is possible to acquire an image with brightness suitable for observation. ing. Specifically, the pre-exposure process is performed by the light emitting unit 22 and the imaging unit 23 in the same frame period before the actual exposure process for actually acquiring one image. The dimmer 21c causes the measurement unit 24e to perform a pre-measurement process that measures the luminance value based on the image signal for the pre-exposure output from the imaging unit 23. In this case, the measurement unit 24e does not perform the luminance value measurement process on the image signals of all the pixels of the CCD array 23a, but performs the luminance value measurement process only on the image signals of some pixels. May be. Similarly, in the main exposure process, the brightness value in the acquired image signal is measured, and the brightness parameter of the next exposure process is reset.

  First, the correcting unit 21a determines whether or not each luminance value has reached a set upper limit value based on the luminance value of each pixel output from the measuring unit 24e. When there is a pixel (saturated pixel) that outputs a luminance value that has reached the set upper limit value, the correction unit 21a performs a correction process of adding a predetermined value to the luminance value of the saturated pixel. For example, when the upper limit value is 255, a pixel having a luminance value of 255 is set as a saturated pixel, and ten to several tens of values are added to the luminance value of the saturated pixel. Hereinafter, the luminance value obtained by the correction unit 21a is referred to as a corrected luminance value.

  The calculation unit 21b calculates the average of these luminance values based on the corrected luminance value corrected by the correction unit 21a and the luminance value that has not reached the upper limit value, and outputs the obtained average luminance value as a photometric value. To do. The obtained photometric value is output to the light control unit 21c.

  The light control unit 21c sets the light emission intensity and the light emission time of the LED 22a in the main exposure process in this frame so that an image with brightness suitable for observation can be acquired based on the photometric value output from the calculation unit 21b. Then, the setting data is output to the LED drive circuit 22b. As a result, the LED 22a emits light with the light emission intensity and the light emission time set by the light control unit 21b under the control of the LED drive circuit 22b.

  In the first embodiment, it is preferable that the luminance value measurement process, the correction process, the calculation process, and the light control process are performed on the image signal captured by the CCD array 23a after the main exposure process. The luminance value by the measurement unit 24e is stored in the memory 21d and may be updated for each dimming process, or may be updated for each frame period.

FIG. 5A is a graph showing an example of the relationship between the light amount and the photometric value in the endoscope system 1 according to the first embodiment, and FIG. 5B shows the relationship between the light amount and the number of saturated pixels. It is a graph which shows. The correction processing by the correction section 21a, 11 to a conventional photometric value output curve L ₁ as shown in (a), the photometric value close to the output light intensity linearly L ₀ when no upper limit is set to the luminance value it is possible to obtain an output curve L _2. Incidentally, the light quantity Q ₁ is, in the target pixel according to the photometric value calculated a quantity of all the pixels is saturated pixels.

Thus, it is possible to perform the dimming process using the photometric values corresponding to the photometric value output curve L ₂ close to the output light intensity linearly L _0. For this reason, even in the case where the halation region H as shown in FIG. 10 exists, in the subsequent imaging processing, the light intensity and / or the light emission time of the LED 22a are adjusted by the light control unit 21c. Thus, the imaging area can be illuminated.

Note that in the graph of FIG. 5 (a), all the pixels is saturated pixels when the light quantity becomes Q _1. For example, a limit value is 255, if the amount of light from LED22a became light amount _{Q 1,} the luminance values outputted from all pixels becomes 255. In this case, the average luminance value (photometric value) of 255, and the even light amount larger than Q _1, the following photometric values, the 255 is the upper limit.

  According to the first embodiment described above, the correction unit 21a individually performs correction processing according to the luminance value based on the image signal captured by the imaging unit 23, and includes the corrected luminance value calculated by the calculation unit 21b. Since the light control unit 21c controls the light emitting unit 22 based on the average value (photometric value) of each luminance value, appropriate illumination adjustment can be performed.

  In the first embodiment described above, the correction unit 21a has been described as adding a predetermined value to the target luminance value, but the luminance value may be multiplied by a predetermined correction coefficient. .

(Embodiment 2)
FIG. 6 is a block diagram schematically illustrating a configuration example of the capsule endoscope 2 according to the second embodiment of the present invention. FIG. 7 is a graph showing the relationship between the number of saturated pixels and the correction value in the endoscope system according to the second embodiment. FIG. 8 is a graph showing the relationship between the light amount and the photometric value in the endoscope system according to the second embodiment. Hereinafter, the same components as those in the endoscope system described above with reference to FIG. In the first embodiment described above, the luminance value correction by the correction unit 21a has been described as giving a constant value. However, the correction unit 21e includes a correction unit 21e that performs a correction process of adding in accordance with the number of saturated pixels. There may be.

  As shown in the graph of FIG. 7, the correction value added to the luminance value increases according to the number of saturated pixels. Note that the saturation pixel number Max in the graph indicates a case where all the pixels for which photometric values are calculated are saturated pixels in the pixels of the CCD array 23a.

  The graph shown in FIG. 7 is stored in the memory 21f, and the correction unit 21e performs luminance value correction processing with reference to this graph. The correcting unit 21e first determines whether or not each luminance value has reached a set upper limit value based on the luminance value of each pixel output from the measuring unit 24e. When there is a pixel (saturated pixel) that outputs a luminance value that has reached the set upper limit value, the correction unit 21a outputs a correction value from the memory 21f with reference to the graph and adds the correction value to the corresponding luminance value. . Thereafter, the photometric value is output by the calculation unit 21b, and the dimming unit 21c controls the operation of the light emitting unit 22 based on the photometric value.

By using the correction value corresponding to the saturated pixel as shown in FIG. 7, as shown in the graph of FIG. 8, the output light amount straight line L ₀ is compared with the photometric value output curve L _{2 according} to the first embodiment described above. it is possible to perform the light control processing by using the photometric values corresponding to more nearly photometric value output curve L ₃ in. For this reason, even in the case where the halation region H as shown in FIG. 10 exists, in the subsequent imaging processing, the light intensity and / or the light emission time of the LED 22a are adjusted by the light control unit 21c. Thus, the imaging area can be illuminated.

  According to the second embodiment described above, as in the first embodiment, the correction unit 21e individually performs correction processing according to the luminance value based on the image signal captured by the imaging unit 23, and is calculated by the calculation unit 21b. Since the light control unit 21c controls the light emitting unit 22 based on the average value (photometric value) of each luminance value including the corrected luminance value, an appropriate illumination adjustment can be performed.

Here, according to the second embodiment, according to the number of saturated pixels. Thus changing the correction value to be added, as compared with the first embodiment described above, further close to the output light intensity linearly L ₀ it is possible to control the light emitting unit 22 by using the light measurement value in accordance with the photometric value output curve L _3.

  FIG. 9 is a graph showing the relationship between the number of saturated pixels and the correction coefficient in the endoscope system according to the modification of the second embodiment of the present invention. In Embodiment 2 described above, the correction unit 21e has been described as adding the correction value to the luminance value, but the luminance value may be multiplied by a correction coefficient.

  As shown in the graph of FIG. 9, when the saturated pixel is 0, the correction coefficient is 1, and as the number of saturated pixels is increased and the number thereof is increased, the correction coefficient is increased (correction coefficient> 1). Thereby, the same effect as in the second embodiment described above can be obtained.

  In the first and second embodiments described above, the memories 21d and 21f store tables and functions, and the dimming unit 21c obtains correction values or correction coefficients by referring to the tables and functions, and controls the light emitting unit 22. May be performed.

  Moreover, in the control part 21, after the calculating part 21b calculates a measured value (average luminance value), you may add a correction value or multiply a correction coefficient. In this case, the correction value and the correction coefficient are preferably set in consideration that the correction target is an average value.

  In the first and second embodiments described above, the dimmer is described as being a capsule endoscope of an endoscope system. However, the light emission intensity and the light emission time of the illumination target each time are applied to the irradiation target. It can be applied as long as the setting is changed.

  As described above, the light control device according to the present invention is useful for performing appropriate illumination adjustment.

1 Subject 2 Capsule endoscope (light control device)
3a to 3h Receiving antenna 3 Receiving device 4 Workstation 5 Recording medium 20 Case 20a Housing (tubular housing)
20b Dome-shaped casing 21 Control unit 21a, 21e Correction unit 21b Calculation unit 21c Light control unit 21d, 21f Memory 22 Light emitting unit (illumination unit)
22a LED
22b LED drive circuit 23 Imaging unit 23a CCD array 23b CCD drive circuit 24 Image signal processing unit 24a A / D conversion unit 24b Amplification unit 24c P / S conversion unit 24d Synchronization signal synthesis unit 24e Measurement unit 25 Wireless transmission unit 25a Transmission circuit 25b Transmitting antenna 26 Power supply circuit 27 Battery 27a First battery 27b Second battery 27c Contact member 28 Pressing member 200 Function execution section 271 Main body section 272 First contact section 273 Second contact section

Claims (4)

An imaging unit having a plurality of pixels that receive light and photoelectrically convert it into an electrical signal;
An illumination unit that emits illumination light that illuminates an area including an imaging region of the imaging unit;
A correction unit that corrects an output value of a saturated pixel that outputs an output value that has reached a set upper limit value among a plurality of output values output from the plurality of pixels based on the electrical signal;
Based on the corrected output value corrected by the correcting unit and the output value output by the pixels other than the saturated pixels, the calculating unit calculates a photometric value that is an average value of the corrected output value and the output value;
Based on the photometric value calculated by the arithmetic unit, a light control unit for controlling the operation of the illumination unit,
A light control device comprising:   The light control apparatus according to claim 1, wherein the correction unit performs correction processing according to the number of the saturated pixels.   The light control device according to claim 1, wherein the correction unit calculates the correction output value by adding a correction value to the output value.   The light control device according to claim 1, wherein the correction unit calculates the correction output value by multiplying the output value by a correction coefficient.

Images