JP2009290734A - Image processor and image processing method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more accurately adjust a white balance, by finding the photographic conditions (especially, the affecting e degree of sunlight) in a photographic position, at the instant of photography. <P>SOLUTION: In an image processor, an antenna 13 receives a signal which is transmitted from a transmitter with a predetermined signal strength, and a signal strength measuring portion 31 measures a signal strength of the signal. A CPU 55 estimates an optical source, at photographing an image by an image pick-up section 12, based on the signal strength measured by the signal strength measuring portion 31. A factor determining portion 53 determines a white balance factor that adjusts the white balance of an image data, output from the image pick-up section 12 corresponding to the optical source thereof. A white balance adjusting portion 43 adjusts the white balance of the image data. For example, the white balance adjusting portion can be applied to a digital camera. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program, and more particularly, to an image processing apparatus, an image processing method, and a program that can adjust white balance more accurately.

  Conventionally, when a subject is imaged with a digital camera, the color temperature of the subject changes in accordance with a light source (illumination light) such as sunlight or a fluorescent lamp. Therefore, in order to reproduce the image color (white) correctly, The white balance is adjusted accordingly. The white balance is adjusted based on, for example, a light source estimated based on a detection result obtained by detecting image data output by the imaging device imaging and outputting a subject, and a white balance coefficient suitable for the light source.

  However, it is generally known that it is difficult to accurately estimate the light source only from the image data. Further, the work of adjusting the white balance is complicated, and skill is required to appropriately adjust the white balance according to the subject. For example, for subjects with very little white, such as a forest with a solid green color, a clear blue sky, and a bright red sunset, errors and errors are likely to occur in the detection results of image data, making it difficult to accurately estimate the light source. It is.

  As described above, since it is difficult to accurately estimate the light source from the image data, for example, the accuracy of estimating the light source is improved by referring to data other than the image data.

  For example, in Patent Document 1, position information on the earth is detected using electromagnetic waves from GPS (Global Positioning System) and the time difference between the altitude of the sun at that position and the daylight entry time at the imaging time. Based on the above, a technique for estimating a light source (for example, whether or not sunset is included) and adjusting white balance is disclosed.

  Patent Document 2 discloses a light source (color) estimated based on weather information based on temperature and pressure detected by a sensor or weather information acquired via a network in correction processing when printing an image. Technology using temperature is disclosed.

JP 2001-39739 A JP 2004-48577 A

  As described above, the light source is estimated using position information, time information, weather information, and the like, but there are still many erroneous estimations. In order to further improve the accuracy of estimating the light source, it is required to know the shooting condition (particularly the influence of sunlight) at the shooting position at the shooting moment and adjust the white balance more accurately.

  The present invention has been made in view of such a situation, and makes it possible to adjust the white balance more accurately.

  An image processing apparatus according to an aspect of the present invention includes a receiving unit that receives a signal transmitted from a transmitting device at a predetermined signal strength, and a signal strength measuring unit that measures the signal strength of the signal received by the receiving unit. Based on the signal intensity measured by the signal intensity measuring means, the estimating means for estimating the light source at the time of imaging by the imaging means for imaging an image, and the imaging means according to the light source estimated by the estimating means Adjusting means for adjusting the white balance of the output image data.

  An image processing method or program according to an aspect of the present invention receives a signal transmitted from a transmission device at a predetermined signal strength, measures the signal strength of the received signal, and based on the measured signal strength A step of estimating a light source at the time of imaging by an imaging unit that captures an image, and adjusting a white balance of image data output from the imaging unit according to the estimated light source.

  In one aspect of the present invention, a signal transmitted from a transmission device with a predetermined signal strength is received, and the signal strength of the signal is measured. Then, based on the signal intensity, the light source at the time of imaging by the imaging unit that captures an image is estimated, and the white balance of the image data output from the imaging unit is adjusted according to the light source.

  According to one aspect of the present invention, white balance can be adjusted more accurately.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration example of an embodiment of a digital camera to which the present invention is applied.

  1, the digital camera 11 includes an imaging unit 12, an antenna 13, a communication processing unit 14, a weather measurement unit 15, an image signal processing unit 16, a recording unit 17, a display unit 18, and a control unit 19.

  The imaging unit 12 includes an optical lens 21 and an imaging element 22. The optical lens 21 has a plurality of lens groups, and forms an image of light of a subject (not shown) on the light receiving surface of the image sensor 22. The image sensor 22 includes an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) sensor, and an electrical signal obtained by photoelectrically converting an image formed by the optical lens 21, that is, a pixel unit. Output image data.

  The antenna 13 receives an electromagnetic wave from a communication device located at a sufficiently high place such as an artificial satellite and supplies it to the communication processing unit 14. Here, as a communication device located in a sufficiently high place, there are a GPS satellite, a satellite that performs communication or broadcasting, a communication device installed on a higher floor of a building on the ground, and the like.

  As will be described later, the communication processing unit 14 supplies the control unit 19 with the signal strength of the communication signal received by the antenna 13 and the feature information obtained by demodulating the communication signal.

  The weather measurement unit 15 includes a temperature sensor, a humidity sensor, and an atmospheric pressure sensor. The weather measurement unit 15 measures temperature, humidity, and atmospheric pressure during imaging by the digital camera 11, and weather information (sunny, cloudy) based on these measurement values. , Information indicating rain, snow, etc.) is supplied to the control unit 19.

  Image data output from the imaging unit 12 is supplied to the image signal processing unit 16. As will be described later, the image signal processing unit 16 supplies the detection result obtained by detecting the image data to the control unit 19, and parameters for adjusting the white balance of the image data output from the imaging unit 12 from the control unit 19. A white balance coefficient is supplied. Then, the image signal processing unit 16 performs white balance adjustment processing based on the white balance coefficient and other various image processing on the image data.

  The recording unit 17 includes various recording media such as a DRAM (Dynamic Random Access Memory) and a flash memory, and is supplied with image data subjected to image processing in the image signal processing unit 16. Record the data.

  The display unit 18 includes a liquid crystal panel and the like, is supplied with image data that has been subjected to image processing in the image signal processing unit 16, and displays an image based on the image data.

  As will be described later, the control unit 19 uses signal strength information and feature information supplied from the communication processing unit 14, weather information supplied from the weather measurement unit 15, and detection results supplied from the image signal processing unit 16. Based on this, a white balance coefficient is determined and supplied to the image signal processing unit 16.

  Next, the communication processing unit 14, the image signal processing unit 16, and the control unit 19 will be described in detail.

  The communication processing unit 14 includes a reception processing unit 33 having a signal strength measurement unit 31 and a demodulation unit 32, and a transmission processing unit 35 having a modulation unit 34.

  The signal strength measurement unit 31 is supplied with the communication signal received by the antenna 13, and the signal strength measurement unit 31 measures the reception strength (level) of the communication signal and controls the signal strength information indicating the reception strength. 19 is supplied.

  A communication signal received by the antenna 13 is supplied to the demodulator 32. The demodulator 32 demodulates the communication signal, and the communication device that is the transmission source outputs the communication signal based on the content of the communication signal. The feature information indicating the features of the communication device including the output intensity and the position (direction or distance) of the communication device is acquired.

  When transmitting information from the digital camera 11 to an external device via the antenna 13, the modulation unit 34 modulates the information and supplies it to the antenna 13. If it is not necessary to transmit information to an external device, it is not necessary to provide the modulation unit 34.

  The image signal processing unit 16 includes a detection unit 41, a general image processing unit 42, a white balance adjustment unit 43, and a compression conversion processing unit 44.

  Image data output from the image sensor 22 is supplied to the detector 41. The detection unit 41 detects an achromatic region (a region determined to be white or light gray (18% gray)) from the image data based on the parameters determined by the control unit 19. Then, the detection unit 41 integrates the pixel value (luminance) of the achromatic color region for each color component, and supplies the integrated values of the R component, G component, and B component to the control unit 19 as detection results.

  Under the control of the control unit 19, the general image processing unit 42 performs general image processing other than the white balance correction processing on the image data output from the image sensor 22, and adjusts the white balance of the image data subjected to the image processing. Supplied to the unit 43. For example, the general image processing unit 42 performs various correction processes such as γ correction, noise reduction process, and the like.

  The white balance adjustment unit 43 is supplied with the white balance coefficient from the coefficient determination unit 53 of the control unit 19, and the white balance adjustment unit 43 receives the image data supplied from the general image processing unit 42 based on the white balance coefficient. Adjust the white balance. That is, the white balance adjustment unit 43 amplifies the R component, the G component, and the B component of the image data with the amplification factor based on the white balance coefficient so that the white color of the subject is reproduced with an accurate white color. to correct.

  The compression conversion processing unit 44 performs compression conversion processing on the image data processed in the general image processing unit 42 and the white balance adjustment unit 43 under the control of the control unit 19. For example, the compression conversion processing unit 44 performs a compression process for converting image data into a predetermined format (for example, JPEG (Joint Photographic Experts Group) or MPEG (Moving Picture Experts Group)) for recording in the recording unit 17. Then, a resolution conversion process for converting to a predetermined size is performed.

  The control unit 19 includes a database 51, a time storage unit 52, a coefficient determination unit 53, a memory 54, and a CPU (Central Processing Unit) 55.

  The database 51 stores a table in which imaging conditions (for example, indoors or outdoors, weather, etc.) at the time of imaging an image are associated with an attenuation rate of received signal strength. The table stored in the database 51 will be described later with reference to FIGS.

  The time storage unit 52 includes a timer that measures time and a memory that stores the output of the timer, and time information indicating the time (year and date) when the image was captured by the digital camera 11 under the control of the CPU 55. Remember.

  Information indicating the light source estimated by the CPU 55 is supplied to the coefficient determination unit 53. The coefficient determination unit 53 determines a white balance coefficient corresponding to the light source. For example, the coefficient determination unit 53 includes a white balance coefficient (R component, G component, and B component that equalizes the R component, G component, and B component of an achromatic region in a predetermined light source and an image captured by the light source. The coefficient determination unit 53 supplies the white balance coefficient associated with the light source estimated by the CPU 55 to the white balance adjustment unit 43.

  The memory 54 is a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory (for example, an EEPROM (Electronically Erasable and Programmable Read Only Memory)), and the like (an algorithm for calculating parameters) executed by the CPU 55. ) And data necessary for the processing of the CPU 55 are stored.

  The CPU 55 executes a program stored in the memory 54 and controls each block of the digital camera 11. For example, the CPU 55 performs control to cause the recording unit 17 to record an image captured by the imaging unit 12 or to display the image on the display unit 18.

  The CPU 55 is supplied with the detection result of the image data from the detection unit 41 of the image signal processing unit 16, and is supplied with the signal strength information from the signal strength measurement unit 31 of the communication processing unit 14, and the demodulation unit of the communication processing unit 14. The feature information of the communication device is supplied from 32, and the weather information is supplied from the weather measurement unit 15. Then, the CPU 55 uses these pieces of information and refers to the database 51 to estimate the light source when the imaging unit 12 takes an image, and supplies information indicating the light source to the coefficient determination unit 53.

  For example, the CPU 55 estimates the light source based on the image data from the detection result of the image data, as in the conventional method. The CPU 55 calculates the attenuation rate of the communication signal based on the output strength of the communication signal included in the feature information of the communication device and the signal strength information from the signal strength measuring unit 31, and refers to the database 51. Then, the imaging condition at the attenuation rate is obtained. Then, if the CPU 55 determines that the reliability of the estimated light source is high from the imaging condition, the CPU 55 uses the light source for white balance adjustment. If the CPU 55 determines that the reliability is low, the CPU 55 estimates a light source with higher reliability using the attenuation rate, weather information, or the like.

  Further, for example, based on the ratio of the achromatic region of the image data, the CPU 55 determines that the reliability of the estimated light source is low if the ratio is low, and determines the light source estimated using other information as white. Use it to adjust the balance.

  Next, a table stored in the database 51 will be described with reference to FIGS.

  FIG. 2 is an example of a table showing the relationship between the attenuation rate of the communication signal and the location and weather as imaging conditions.

  As shown in FIG. 2, the attenuation rate used as a threshold value between sunny and cloudy is 20% outdoors, and the attenuation rate used as a threshold value between cloudy and rain or snow is 40%. The attenuation rate used as a threshold for extremely bad weather is 60%. Also, indoors, the signal strength is attenuated by the building. Therefore, the attenuation rate used as the threshold value for clear weather and cloudy is 40%, and the attenuation rate used as the threshold value for sunny and cloudy. Is 60%, and the attenuation rate used as a threshold value between cloudy and rainy or snow is 80%.

  As described above, in the table of FIG. 2, six threshold values of the attenuation rate for obtaining the imaging condition are registered. Note that the boundary of each parameter may change due to a difference in output intensity of the transmission source communication device, and the threshold value of the attenuation factor may be changed according to the difference. That is, the threshold value is not fixed to the value shown in the example of FIG. Further, for convenience, one type of indoor example is used, but the database 51 is obtained by measuring the threshold value in more detail according to parameters such as the material of the building (wooden, concrete, glass, etc.) and the thickness of the building. The contents of can be detailed.

  The table in FIG. 2 will be described with reference to FIG.

  For example, when the imaging location is outdoors, factors that contribute to the attenuation of communication signals include dust in the universe, near-surface conditions according to the atmosphere and weather (for example, clouds, rain, snow, fog). is there. Therefore, if the attenuation rate is 0 to 20%, it is considered that there is almost no obstruction, and the attenuation is a clear state. If the attenuation rate is 20 to 40%, the attenuation is caused by clouds. If the attenuation rate is 40 to 60%, the attenuation is caused by normal rain or snow. If the attenuation rate is 60 to 100%, the weather is bad. (Deep rain or storm) and attenuation when sunlight does not reach.

  In addition, when the imaging location is indoors, the communication signal is attenuated by the building in addition to attenuation due to weather. Here, it is assumed that there is at least 40% attenuation depending on the building, and the attenuation rate is not 0 to 40%. If it is 40 to 60%, the attenuation is caused by the building and clear weather, and the attenuation rate is 60 to 60%. If it is 80%, it is considered as attenuation due to the building and cloudiness. If the attenuation rate is 80 to 100%, it is a state where the building is attenuated by normal rain or snow, or a state where the building is deep, such as underground, and is hardly affected by sunlight regardless of the weather. Is done.

  Next, FIG. 4 is a flowchart for explaining white balance adjustment processing in the digital camera 11 of FIG.

  For example, when the power is turned on to the digital camera 11 and the imaging unit 12 starts imaging, the process is started. In step S11, the imaging element 22 of the imaging unit 12 starts outputting image data obtained as a result of imaging the subject. To do. The detection unit 41 and the general image processing unit 42 of the image signal processing unit 16 acquire the image data output from the image sensor 22, and the process proceeds to step S12.

  In step S <b> 12, the signal strength measuring unit 31 supplies signal strength information indicating the signal strength of the communication signal received by the antenna 13 to the CPU 55, and the demodulating unit 32 of the communication device obtained from the communication signal received by the antenna 13. The feature information is supplied to the CPU 55. Further, the weather measurement unit 15 supplies the CPU 55 with weather information based on the measured values of temperature, humidity, and atmospheric pressure. The CPU 55 acquires such information, and the process proceeds to step S13.

  In step S13, the CPU 55 calculates the attenuation rate of the received signal based on the signal strength information supplied from the signal strength measuring unit 31 and the feature information supplied from the demodulating unit 32 in step S12. That is, as described above, the feature information includes the output intensity at which the communication device outputs the communication signal, and the CPU 55 calculates, for example, the ratio of the signal intensity of the received signal to the output intensity as the attenuation rate. To do.

  After the process of step S13, the process proceeds to step S14, and the CPU 55 performs estimation based on the attenuation rate calculated in step S13. For example, the CPU 55 refers to the database 51 and estimates the imaging condition corresponding to the attenuation rate calculated in step S13 as a condition when an image is captured by the imaging unit 12.

  After the process of step S14, the process proceeds to step S15, and the CPU 55 performs an estimation process (process of the flowchart in FIG. 5) for estimating the light source based on the image captured by the image sensor 22, and the process proceeds to step S16. . This estimation process is the same as the process performed in the conventional digital camera.

  In step S16, the CPU 55 determines whether or not the imaging condition estimated based on the attenuation rate in step S14 matches the light source estimated in the estimation process in step S15.

  For example, as an example in which it is determined that the imaging condition estimated based on the attenuation rate in step S14 matches the light source estimated in the estimation process in step S15, the imaging condition is outdoor and sunny or cloudy. Is sunlight, the imaging conditions are outdoors and extremely bad weather, and the light source is artificial lighting (fluorescent / incandescent bulb), the imaging conditions are indoors and cloudy, rainy or snowy, and the light source is artificial There are cases where it is illumination (fluorescent light / incandescent light bulb).

  Further, as an example in which it is determined that the imaging condition estimated based on the attenuation rate in step S14 and the light source estimated in the estimation process in step S15 do not match, the imaging condition is outdoor and sunny or cloudy When the light source is artificial lighting (fluorescent lamp / incandescent light bulb), the imaging condition is outdoor and extremely bad weather, and the light source is sunlight, the imaging condition is indoor and cloudy, rainy or snowy. May be sunlight. Here, when the attenuation rate calculated in step S13 is 40 to 80%, there is a possibility that both sunlight and artificial lighting have an influence, and the imaging condition may be determined in step S14. Since it is not possible (it is a gray loss), it is determined that the imaging condition and the light source do not match, and processing is performed after adding time information and weather information.

  If the CPU 55 determines in step S16 that the imaging condition does not match the light source, the process proceeds to step S17.

  In step S17, the CPU 55 performs an estimation process (the process in the flowchart of FIG. 6) for estimating the light source based on the plurality of information acquired in step S12.

  After the estimation process in step S16, or when the CPU 55 determines in step S15 that the imaging condition matches the light source, the process proceeds to step S18.

  In step S18, the coefficient determination unit 53 determines a white balance coefficient. For example, if it is determined in step S16 that the imaging condition matches the light source, information indicating the light source estimated in the estimation process in step S15 is supplied from the CPU 55 to the coefficient determining unit 53, and the coefficient determining unit 53 determines a white balance coefficient based on the light source. On the other hand, when it is determined in step S16 that the imaging condition and the light source do not match, information indicating the light source is supplied to the coefficient determination unit 53 in the estimation process performed in step S17, and the coefficient determination unit 53 53 determines a white balance coefficient based on the light source. The coefficient determination unit 53 supplies the white balance coefficient to the white balance adjustment unit 43, and the process proceeds to step S19.

  In step S19, the white balance adjustment unit 43 adjusts the white balance of the image data output from the image sensor 22 based on the white balance coefficient supplied from the coefficient determination unit 53 in step S18, and the process ends.

  Next, FIG. 5 is a flowchart illustrating the estimation process in step S15 of FIG.

  In step S21, the detection unit 41 estimates a pixel that is an achromatic region according to a preset parameter indicating the color balance, and the process proceeds to step S22.

  In step S22, the detection unit 41 determines whether or not the pixel estimated to be an achromatic region in step S21 matches a selection condition that is a predetermined condition to be used for light source estimation. .

  If it is determined in step S22 that the selection condition is not met, the process returns to step S21, and a process for estimating a pixel that is an achromatic region is performed by changing the parameters, and it is determined that the selection condition is met. Repeated until

  If it is determined in step S22 that the detection unit 41 matches the selection condition, the process proceeds to step S23, and the detection unit 41 sets the pixel value (luminance) of the pixel that matches the selection condition for each color component. Integrate.

  After the process of step S23, the process proceeds to step S24, and the detection unit 41 supplies an integrated value obtained by integrating the pixel value of the pixel for each color component to the CPU 55 as a detection result. Based on the detection result, the CPU 55 estimates a light source based on, for example, a balance (ratio) of pixel values for each color component, and the estimation process ends.

  Next, FIG. 6 is a flowchart illustrating the estimation process in step S17 of FIG.

  In step S31, the CPU 55 obtains the total number of pixels of the image data acquired in step S11. Whether the ratio of the number of pixels estimated as the achromatic region in step S21 in FIG. 5 is 40% or more. Determine whether or not.

  In step S31, when the CPU 55 determines that the ratio of the number of pixels estimated to be the achromatic region to be the total number of pixels of the image data is 40% or more, the process proceeds to step S32.

  In step S32, the CPU 55 selects the light source estimated in the estimation process based on the image in step S15 of FIG. 4 as the light source used for determining the white balance coefficient. Then, the CPU 55 supplies information indicating the light source to the coefficient determination unit 53, and the process ends. That is, in this case, since the ratio of the achromatic region included in the image data is high and the light source is estimated using the pixel values of many pixels, the reliability of the estimation result in the estimation process based on the image is high, Therefore, the estimation result is selected.

  On the other hand, when the CPU 55 determines in step S31 that the ratio of the number of pixels estimated to be the achromatic region to be the total number of pixels of the image data is not 40% or more, the process proceeds to step S33.

  In step S <b> 33, the CPU 55 determines whether or not the ratio of the number of pixels estimated to be an achromatic region that is used as the total number of pixels of the image data is less than 5%. That is, when the ratio of the number of pixels of the pixels estimated to be the achromatic region to be reduced to the total number of pixels of the image data is less than 5%, the ratio of the achromatic region included in the image data is extremely low. Since the number of pixels used for the estimation is too small, the reliability of the estimation result in the image-based estimation process is extremely low, and therefore the light source is estimated based on the signal attenuation rate.

  In step S33, when the CPU 55 determines that the ratio of the number of pixels estimated to be the achromatic region to be the total number of pixels of the image data is less than 5%, the process proceeds to step S34, and the CPU 55 Then, it is determined whether or not the attenuation rate of the received signal calculated in step S13 in FIG. 4 is 80% or more.

  In step S34, when the CPU 55 determines that the attenuation rate of the received signal is 80% or more, the process proceeds to step S35, and the CPU 55 selects an artificial light source as a light source used to determine the white balance coefficient. That is, in this case, since the attenuation rate of the received signal is high, it is considered that it is hardly affected by sunlight. The CPU 55 supplies information indicating the artificial light source to the coefficient determination unit 53, and the process ends.

  On the other hand, when the CPU 55 determines in step S34 that the attenuation rate of the received signal is not 80% or more, the process proceeds to step S36, and the CPU 55 determines whether or not the attenuation rate of the received signal is less than 40%. .

  In step S36, when the CPU 55 determines that the attenuation rate of the received signal is less than 40%, the process proceeds to step S37, and the CPU 55 selects sunlight as a light source used to determine the white balance coefficient. That is, in this case, since the attenuation rate of the received signal is low, the possibility of being outdoors is considered high. CPU55 supplies the information which shows sunlight to the coefficient determination part 53, and a process is complete | finished.

  Next, when the CPU 55 determines in step S33 that the ratio of the number of pixels estimated to be the achromatic region to be the total number of pixels of the image data is not less than 5%, or in step S36, the CPU 55 If it is determined that the attenuation rate of the received signal is not less than 40%, the process proceeds to step S38. That is, in this case, there is a certain proportion of the achromatic region and the attenuation rate of the received signal is intermediate, and it is difficult to accurately determine whether the attenuation rate of the received signal is due to location or weather. Therefore, other information is used.

  In step S38, the CPU 55 refers to the time information stored in the time storage unit 52, and determines whether or not the time when the image is captured by the imaging unit 12 is nighttime.

  Here, for example, in order for the CPU 55 to accurately determine whether the time is nighttime, for example, the sunrise / sunset information is stored in the database 51 and the communication processing unit 14 is used. The position information may be acquired based on a signal output from a GPS satellite or the like by communication. Then, the CPU 55 can more accurately determine whether or not the time is nighttime by referring to the database of the sunrise and sunset information based on the position information and the time information. The time storage unit 52 acquires time information using a built-in timer, and based on information output from a GPS satellite, information obtained from a time server, and the like by communication via the communication processing unit 14. Time information may be acquired.

  In step S38, when the CPU 55 determines that the time is nighttime, the process proceeds to step S39, and the CPU 55 selects an artificial light source as a light source used to determine the white balance coefficient. That is, in this case, it is considered that there is no possibility that sunlight is a light source. The CPU 55 supplies information indicating the artificial light source to the coefficient determination unit 53, and the process ends.

  On the other hand, when the CPU 55 determines in step S38 that the time is not nighttime, the process proceeds to step S40, and the CPU 55 determines that the weather information supplied from the weather measurement unit 15 is sunny with a relatively large influence of sunlight. Alternatively, it is determined whether or not clouding is indicated.

  In step S40, when the CPU 55 determines that the weather information indicates clear or cloudy, the process proceeds to step S41, and the CPU 55 determines whether or not the attenuation rate of the received signal is less than 40%.

  In step S41, when the CPU 55 determines that the attenuation rate of the received signal is less than 40%, the process proceeds to step S42, and the CPU 55 selects sunlight as a light source used to determine the white balance coefficient. CPU55 supplies the information which shows sunlight to the coefficient determination part 53, and a process is complete | finished.

  On the other hand, if the CPU 55 determines in step S41 that the attenuation rate of the received signal is not less than 40%, the process proceeds to step S43, and the CPU 55 selects an artificial light source as a light source used to determine the white balance coefficient. . The CPU 55 supplies information indicating the artificial light source to the coefficient determination unit 53, and the process ends.

  On the other hand, if the CPU 55 determines in step S40 that the weather information does not indicate clear or cloudy, for example, if the weather information indicates rain or snow, the process proceeds to step S44, and the CPU 55 It is determined whether or not the signal attenuation rate is less than 60%.

  In step S44, when the CPU 55 determines that the attenuation rate of the received signal is less than 60%, the process proceeds to step S45, and the CPU 55 selects sunlight as a light source used to determine the white balance coefficient. CPU55 supplies the information which shows sunlight to the coefficient determination part 53, and a process is complete | finished.

  On the other hand, when the CPU 55 determines in step S44 that the attenuation rate of the received signal is not less than 60%, the process proceeds to step S46, and the CPU 55 selects an artificial light source as a light source used to determine the white balance coefficient. . The CPU 55 supplies information indicating the artificial light source to the coefficient determination unit 53, and the process ends.

  Here, in step S35, step S39, step S43, or step S46, an artificial light source is selected as the light source. However, there are a plurality of types of artificial light sources such as fluorescent lights and light bulbs, and the artificial light source is selected. In addition, in the estimation process based on the image (the process of the flowchart of FIG. 5), when the light source is estimated to be sunlight, it is again assumed that a condition other than sunlight is selected as a condition for selecting the light source. After selecting the most likely light source, the most likely light source may eventually be determined.

  As described above, since the digital camera 11 uses not only the image data but also the attenuation rate of the communication signal for the estimation of the light source, the accuracy of estimating the light source can be improved as compared with the case of using only the image data. Further, by further using weather information and time information for light source estimation, the accuracy of light source estimation can be further increased. As described above, by estimating the light source more finely than in the past, the white balance can be adjusted more accurately than in the past.

  That is, for example, when estimating a light source using only image data, an error may occur in the process of estimating the achromatic region or the process of determining the selection condition for use in estimating the light source. In some cases, errors may accumulate in the integrated value, and the reliability of the light source estimated from the detection result of the image data may be low. In particular, when the achromatic region included in the image is small, the reliability of the estimated light source is low.

  On the other hand, in the digital camera 11, the reliability of the light source estimated from the detection result of the image data can be confirmed from the attenuation rate of the received signal, and when the reliability is low, based on a plurality of information. Since the light source is estimated, the reliability of the light source estimation can be improved. In addition, when the achromatic region included in the image is small, the reliability is improved by estimating the light source based on the attenuation rate of the received signal without using the light source with low reliability estimated from the image data. And the white balance can be adjusted accurately.

  Alternatively, the estimated light source may be displayed on the display unit 18 and presented to the user to prompt the user to adjust the light source.

  In this embodiment, an estimation process for estimating a light source based on image data is performed. However, for example, a function for performing this estimation process cannot be incorporated in the control unit 19 due to restrictions such as a gate size. There is a case. However, even in such a case, the digital camera 11 can estimate the light source to some extent by performing the estimation based on the attenuation rate of the received signal.

  In addition, when there are a plurality of communication devices that transmit communication signals, for example, when the communication processing unit 14 receives communication signals from a plurality of satellites, the imaging conditions can be obtained from the attenuation rates of the plurality of communication signals. More accurate imaging conditions can be obtained, and thereby white balance can be adjusted more accurately.

  For example, when the communication processing unit 14 receives communication signals from four satellites, if the attenuation rate of the communication signals from the four satellites is low, it can be estimated that imaging is performed outdoors with a good view. . Moreover, if the attenuation rate of one communication signal out of the four satellites is high, the shadow of the building even outdoors (shadow on the satellite that transmitted the communication signal having a high attenuation rate) It can be estimated that the image is being taken. Furthermore, if you know the direction of the satellite from the feature information, you can tell which direction the building is located. For example, if you know that there is a building on the south side, it is estimated that there is a high probability of being shaded, A suitable white balance coefficient can be selected. Thus, by obtaining imaging conditions from communication signals from a plurality of satellites, reliability can be improved as compared to the case of communication signals from one satellite.

  Further, when the reception position information indicating the reception position where the communication processing unit 14 has received the communication signal is acquired, for example, the propagation distance of the communication signal is checked by checking with the transmission position information included in the feature information of the communication device. It is also possible to calculate the exact direction of the communication device. For example, by creating a table in which the propagation distance of the communication signal, the direction of the communication device, and the like are associated with the imaging conditions in advance, by referring to the table, more accurate imaging conditions can be obtained. As a result, the white balance can be adjusted more accurately. The reception position information may be input by the user to the digital camera 11 or acquired by communication with a GPS satellite.

  Further, for example, by registering a light source corresponding to a time zone such as morning, noon, and night in the database 51, the light source is estimated with reference to the database 51 based on the time information obtained from the time storage unit 52. be able to. For example, when the time is night, it can be estimated that the possibility that sunlight is a light source is low.

  Furthermore, for example, time information and information indicating the angle of the sun are associated with each other and registered in the database 51, or satellite position information or the like is registered in the database 51. The light source can be estimated accurately, and as a result, the white balance can be adjusted more accurately.

  Further, as described with reference to FIG. 2, the attenuation rate and the weather are associated with each other in the database 51. For example, the digital camera 11 does not include the weather measurement unit 15, or the communication processing unit 14. Even when the weather information cannot be acquired via the network via the network, the light source can be estimated based on the weather information by referring to the database 51. That is, the digital camera 11 does not necessarily include the weather measurement unit 15, and can estimate the light source based on the weather information without incurring the cost of providing the weather measurement unit 15.

  For example, in the digital camera 11, the weather information acquired via the network via the communication processing unit 14 may be used. However, the weather information indicates the weather in the time zone of the area. This is because the time and place where the image was taken by the digital camera 11 deviated. Moreover, it may be difficult to determine the weather only with measured values such as temperature, humidity, and atmospheric pressure acquired by the weather measurement unit 15. Therefore, by using not only the weather information acquired via the communication processing unit 14 and the weather information based on the measurement result of the weather measurement unit 15 but also the weather information obtained by referring to the database 51, the weather at the time of imaging can be determined. It can be obtained more accurately.

  The digital camera 11 has a built-in database 51, but an external database may be referred to via the communication processing unit 14, for example. In this case, there is no limit on the capacity of information registered in the database, and a more detailed database can be created. Then, by referring to a detailed database, it is possible to estimate light sources classified in detail, and thereby it is possible to adjust white balance in more detail.

  In addition, the CPU 55 built in the digital camera 11 does not perform calculations based on various types of information, but transmits the information to an external database server via the communication processing unit 14, and a CPU with higher processing capability. It is also possible to perform the calculation at and to refer to a larger database. As a result, there are no restrictions associated with the processing capacity of the CPU 55, more complex calculations can be performed, and white balance can be adjusted in more detail.

  Note that the timing at which the signal strength measuring unit 31 acquires the signal strength of the communication signal is not limited to when the image capturing unit 12 captures an image. For example, the signal strength measuring unit 31 can periodically acquire the signal strength, use a value obtained by averaging a plurality of signal strengths, or use a weighted value as necessary. The reliability of the signal strength can be improved.

  Further, for example, when a communication signal that can be received by the communication processing unit 14 is determined in advance, and the position and output intensity of the communication device that outputs the communication signal are fixed, the information is stored. By storing in advance, it is not necessary for the demodulator 32 to acquire the feature information of the communication device.

  The digital camera 11 can record the image data output from the image pickup unit 12 in the recording unit 17 without performing image processing. As information accompanying the image data, the signal strength of the communication signal, the communication device Feature information, weather information, time information, and the like can be recorded in the recording unit 17. Thereby, for example, when a user performs image processing using a personal computer, it is possible to perform more optimal image processing by referring to the information.

  In addition, the processes described with reference to the flowcharts described above do not necessarily have to be processed in time series in the order described in the flowcharts, but are performed in parallel or individually (for example, parallel processes or objects). Processing). The program may be processed by one CPU, or may be processed in a distributed manner by a plurality of CPUs. In addition, the program can be downloaded via the communication processing unit 14 and installed in the memory 54 as necessary.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is a block diagram which shows the structural example of one Embodiment of the digital camera to which this invention is applied. It is an example of the table which showed the relationship between the attenuation factor of a communication signal, the place as an imaging condition, and the weather. It is a figure explaining the table of FIG. 3 is a flowchart for explaining white balance adjustment processing in the digital camera 11; It is a flowchart explaining the estimation process based on an image. It is a flowchart explaining the estimation process based on several information.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Digital camera, 12 Imaging part, 13 Antenna, 14 Communication processing part, 15 Weather measurement part, 16 Image signal processing part, 17 Recording part, 18 Display part, 19 Control part, 21 Optical lens, 22 Imaging element, 31 Signal intensity Measurement unit, 32 demodulation unit, 33 reception processing unit, 34 modulation unit, 35 transmission processing unit, 41 detection unit, 42 general image processing unit, 43 white balance adjustment unit, 44 compression conversion processing unit, 51 database, 52 time storage unit , 53 Coefficient determination unit, 54 memory, 55 CPU

Claims (8)

Receiving means for receiving a signal transmitted from the transmitting device at a predetermined signal strength;
Signal strength measuring means for measuring the signal strength of the signal received by the receiving means;
Based on the signal intensity measured by the signal intensity measuring means, an estimating means for estimating a light source at the time of imaging by an imaging means for imaging an image;
An image processing apparatus comprising: an adjustment unit that adjusts a white balance of image data output from the imaging unit according to the light source estimated by the estimation unit. Calculating means for calculating an attenuation rate of the signal intensity measured by the signal intensity measuring means with respect to a predetermined signal intensity at which the communication device transmits a signal;
The image processing apparatus according to claim 1, further comprising: a database in which imaging conditions during imaging by the imaging unit and the attenuation rate are associated and registered. A detector for detecting image data output from the imaging unit;
The image processing apparatus according to claim 1, wherein the estimation unit estimates the light source by further using a detection result obtained by the detection unit. The image processing apparatus according to claim 3, wherein the estimation unit determines whether or not to use a detection result by the detection unit according to a ratio of an achromatic region when the detection unit detects image data. Weather information acquisition means for acquiring weather information at the time of imaging by the imaging means,
The image processing apparatus according to claim 1, wherein the estimation unit estimates the light source by further using weather information acquired by the weather information acquisition unit. Further comprising time information acquisition means for acquiring time information at the time of imaging by the imaging means,
The image processing apparatus according to claim 1, wherein the estimation unit estimates the light source by further using time information acquired by the time information acquisition unit. Receive a signal transmitted from the transmitter with a predetermined signal strength,
Measuring the signal strength of the received signal;
Based on the measured signal intensity, estimate the light source at the time of imaging by the imaging means for imaging an image,
An image processing method including a step of adjusting a white balance of image data output from the imaging unit according to the estimated light source. Receive a signal transmitted from the transmitter with a predetermined signal strength,
Measuring the signal strength of the received signal;
Based on the measured signal intensity, estimate the light source at the time of imaging by the imaging means for imaging an image,
A program that causes a computer to execute image processing including a step of adjusting white balance of image data output from the imaging unit in accordance with the estimated light source.

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