JP2014183516A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera capable of obtaining an image having a maximum effect of a polarizing filter after capturing a plurality of images at different filter positions by rotating the polarizing filter.SOLUTION: A camera includes: a polarizing filter capable of rotating around a rotation axis which includes an optical axis of an optical lens and is parallel to the optical axis; imaging means for capturing images through the optical lens and the polarizing filter; detection means for detecting a rotation angle of the polarizing filter with respect to a reference angle; photometric means for measuring a luminance value of light made incident through the optical lens and the polarizing filter; and control means. The control means obtains a first rotation angle, of the polarizing filter, at which the luminance value measured by the photometric means is maximized; creates a difference image by obtaining a difference between a first image captured by the imaging means at the first rotation angle, of the polarizing filter, at which the luminance value is maximized and a second image captured by the imaging means at a second rotation angle, of the polarizing filter, which is previously specified; and records the first image and the difference image in a storage medium by associating the first image with the difference image.

Description

  The present invention relates to a camera using a polarizing filter.

  A general camera uses a polarization filter for removing a light component in a specific direction during photographing. The polarizing filter can change the polarization direction of the light component to be removed by rotating the filter member. For example, when there is a glass window between the camera and the subject, the polarizing filter can effectively remove unnecessary reflected light from the glass window. In general, the polarizing filter is mounted on the front surface of the lens of the camera, and the user adjusts the angle so that a desired light component can be removed while manually rotating the filter member. Therefore, a technique for automatically searching for an effective angle has been studied (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 03-192231

  In the prior art, a rotatable polarizing filter inserted in the photographing optical path is rotated to photograph an image having a rotation angle at which the photometric value becomes the minimum value or the maximum value. However, the user expects the effect of a polarizing filter that can selectively and intentionally remove light from an undesired direction, but it does not necessarily have a correlation with the photometric value, and is automatically determined. In some cases, an image taken at a different rotation angle is contrary to the user's intention. In this case, the effect of the polarizing filter applied to the photographed image is fixed to the filter effect at a predetermined rotation angle, and there is a drawback that it cannot be redone.

  In view of the above problems, an object of the present invention is to provide a camera capable of adjusting the effect of a polarizing filter after photographing.

  The camera according to the present invention includes a polarizing filter that includes an optical axis of an optical lens and is rotatable on a rotation axis parallel to the optical axis, an imaging unit that captures an image through the optical lens and the polarizing filter, A detecting means for detecting a rotation angle with respect to a reference angle; a photometric means for measuring a luminance value of light incident through the optical lens and the polarizing filter; and a polarizing filter having a maximum luminance value measured by the photometric means. A rotation angle of 1 is obtained, and a first image photographed by the photographing means at the first rotation angle of the polarization filter having the maximum luminance value and a second rotation of the polarization filter designated in advance A difference image is obtained by obtaining a difference from the second image photographed by the photographing means at an angle, and the first image and the difference image are associated with each other and a storage medium And having a control means for recording.

  The camera according to the present invention can adjust the effect of the polarizing filter after photographing.

It is a figure which shows the structural example of the camera 100 which concerns on this embodiment. It is a figure which shows the structural example of the polarizing filter 101b. It is a flowchart which shows the process at the time of imaging | photography. It is a figure which shows an example of the image data preserve | saved at the memory card 106a. It is a figure which shows an example of the adjustment method of a filter effect. It is a figure which shows an example of calculation of a difference image, and calculation of a filter effect. It is a flowchart which shows an example of the adjustment process of a filter effect.

Hereinafter, a camera embodiment according to the present invention will be described in detail with reference to the drawings.
[Configuration Example of Camera 100]
FIG. 1 is a block diagram illustrating an example of the camera 100. In FIG. 1, a camera 100 includes a lens unit 101, an imaging unit 102, an image buffer 103, an image processing unit 104, a control unit 105, a memory card IF (interface) 106, a display unit 107, and an operation unit. 108, a nonvolatile memory 109, and an angle detection unit 110. Furthermore, the camera 100 may include a drive unit 111 and a photometry unit 112.

  The lens unit 101 includes at least one optical lens 101a and a polarizing filter 101b. The optical lens 101 a forms an image of light incident from the subject on the light receiving surface of the imaging unit 102. The polarizing filter 101b is an optical filter for removing light components from a specific direction at the time of photographing. The polarizing filter 101b has a mechanism that can rotate around the optical axis or an axis parallel to the optical axis, and can change the polarization direction for removing the light component.

  Here, the polarizing filter 101b may be rotated manually by the photographer, or may be rotated by a command from the control unit 105 by providing a dedicated driving unit 111.

  The imaging unit 102 includes an imaging element, an A / D converter, and the like. Then, the subject image formed on the light receiving surface of the image sensor by the lens unit 101 is converted into an electrical signal corresponding to the amount of light, and further converted into digital image data by the A / D converter and stored in the image buffer 103. It is captured. Note that the image sensor is composed of a plurality of pixels (for example, 36 million pixels) arranged in a matrix, and each pixel has a color filter of any one of RGB three colors arranged in a Bayer array or the like. Then, the control unit 105 reads out RAW data (raw image data that is not processed and output from the image sensor) of any of RGB color components from each pixel and captures it in the image buffer 103 for each shooting.

  The image buffer 103 uses, for example, a memory that can be read and written at high speed, and temporarily stores an image captured by the imaging unit 102. The image buffer 103 is also used as a buffer when the image processing unit 104 or the control unit 105 processes image data.

  The image processing unit 104 performs image processing on the RAW data image captured by the imaging unit 102 and the captured image.

  Here, the image processing unit 104 performs image processing such as color interpolation processing, white balance processing, gamma correction processing, and contour enhancement processing. The color interpolation process interpolates RAW data in which each pixel has information on only one color component of the RGB three colors, and converts it into luminance / color difference data such as RGB data and YCbCr data having information on the RGB three colors in each pixel. It is a process to convert. The image processing unit 104 also performs image compression processing according to the JPEG standard or the like in order to save the image subjected to image processing in the memory card 106a.

  The control unit 105 includes a CPU (Central Processing Unit), an interface circuit, and the like, and operates according to a program code stored in advance in a memory inside the CPU or the nonvolatile memory 109. For example, the control unit 105 controls the exposure conditions (aperture value, shutter speed, ISO sensitivity, exposure time, etc.) when the image capturing unit 102 captures an image. Here, the control unit 105 measures the luminance value of the subject incident through the lens unit 101 in order to determine the exposure condition. Note that the luminance value of the subject may be calculated from an image output from the imaging unit 102 or may be measured by providing a dedicated photometric unit 112.

  Further, the control unit 105 performs selection of a shooting mode, setting of shooting conditions, shooting processing, reproduction processing, and the like based on operation information input from the operation unit 108. For example, when the release button of the operation unit 108 is pressed, the control unit 105 captures an image with the imaging unit 102 and loads the image into the image buffer 103, performs image processing with the image processing unit 104, and stores the image in the memory card 106 a. Process. In addition, when the playback button for the captured image is selected by the operation unit 108, the control unit 105 performs processing for reading the captured image data stored in the memory card 106 a and displaying it on the display unit 107. Further, the control unit 105 displays not only the image on the display unit 107 but also displays an operation menu on the display unit 107 to perform processing for setting shooting conditions, a shooting mode, and the like. The control unit 105 acquires the rotation angle of the polarization filter 101b from the angle detection unit 110, and stores the rotation angle information (hereinafter referred to as rotation) when the image data of the image captured by the imaging unit 102 is stored in the memory card 106a. (Referred to as angle information) is stored in association with the image data. Note that the rotation angle information is associated with the image data, for example, when the file format conforms to the Exif standard, the rotation angle information is stored and saved in the header of the image data. Alternatively, the rotation angle information and the image data may be saved in separate files and associated with each other by file name, attribute, etc., or created by creating a table indicating the correspondence between the rotation angle information and the image data The stored table may be saved. In addition, the camera 100 according to the present embodiment has a “polarization filter effect adjustment function”, and the effect of the polarization filter 101b on an image captured in the “polarization filter imaging mode” and stored in the memory card 106a. Can be adjusted. In the present embodiment, the control unit 105 captures at least two images at different rotation angles of the polarizing filter 101b and stores them in the memory card 106a so that the effect of the polarizing filter 101b can be adjusted after capturing. Here, at least two images stored in the memory card 106a are one reference image, and the remaining images are difference images between an image having a rotation angle different from that of the reference image and the reference image. Alternatively, the remaining image may be an image having a rotation angle different from that of the reference image instead of the difference image. The reference image is an image taken at a rotation angle of the polarizing filter 101b having the maximum luminance value, for example. And the control part 105 performs the process which adjusts the effect of the polarizing filter 101b with respect to the image | photographed image.

  The memory card IF 106 is an interface circuit for connecting the memory card 106a. The control unit 105 accesses the memory card 106a via the memory card IF 106, and writes and reads image data.

  For example, a liquid crystal monitor is used as the display unit 107, and an image output from the control unit 105, an operation menu, and the like are displayed. In this embodiment, when the “polarization filter effect adjustment function” is activated by the operation unit 108, the control unit 105 displays an operation screen for adjusting the filter effect on the display unit 107. Then, a process for adjusting the effect of the polarization filter 101b is performed on the image after shooting by a user operation, and the adjusted image is displayed on the display unit 107.

  The operation unit 108 includes a power button for turning on / off the power, a release button for giving a shooting instruction, a selection dial for selecting a shooting mode, a cursor button and a determination button for operating a setting menu, a touch panel, and the like. The operation member is provided. The camera 100 according to the present embodiment has a “polarization filter imaging mode” and can capture a plurality of images with different rotation angles of the polarization filter 101b. In addition, the camera 100 according to the present embodiment has a “polarization filter effect adjustment function”, and the user can adjust the effect of the polarization filter 101b on an image after shooting, for example, by operating a touch panel.

  As the non-volatile memory 109, a non-volatile memory capable of holding stored contents even when the power is turned off is used. The nonvolatile memory 109 stores the program code of the control unit 105, parameters necessary for operation, contents set by an operation menu, and the like. For example, in the “polarization filter imaging mode”, parameters such as exposure conditions when rotating an image while rotating the polarizing filter 101b and intervals of rotation angles are stored. Note that the image data of the photographed image may be stored in the nonvolatile memory 109 as in the memory card 106a.

  The angle detection unit 110 detects the rotation angle of the polarizing filter 101b.

  The drive unit 111 is a drive mechanism that changes the rotation angle of the polarizing filter 101b according to a command from the control unit 105.

  The photometry unit 112 is a dedicated component for measuring the luminance value of light incident from the lens unit 101. Note that the brightness value may be obtained from an image captured in the image buffer 103 in real time by the imaging unit 102 instead of the photometric unit 112.

  Next, processing of the control unit 105 will be described. In FIG. 1, the control unit 105 includes a rotation processing unit 151, a photographing processing unit 152, a reproduction processing unit 153, and a polarization filter effect adjustment processing unit 154.

  The rotation processing unit 151 performs processing for detecting the rotation direction and rotation angle of the polarizing filter 101b based on the output information of the angle detection unit 110. In addition, when it has the drive part 111, the rotation process part 151 performs the process which rotates the polarizing filter 101b.

  The imaging processing unit 152 performs processing for capturing an image by controlling the imaging unit 102, processing for measuring a luminance value of a subject image by the imaging unit 102 or the photometry unit 112, and the like. Further, the photographing processing unit 152 performs processing for setting exposure conditions based on the photographing mode selected by the operation unit 108. Furthermore, the imaging processing unit 152 instructs the image processing unit 104 to perform image processing on the captured image, displays the captured image on the display unit 107, and stores the image data of the captured image on the memory card 106a. Process. The imaging processing unit 152 associates the image data of the captured image with information on the rotation angle of the polarization filter 101b when the image is captured, and stores the image data in the memory card 106a.

  The reproduction processing unit 153 reads the captured image data stored in the memory card 106 a and performs processing for displaying the image of the read image data on the display unit 107. Then, the reproduction processing unit 153 reads information on the rotation angle of the polarizing filter 101b stored in association with the captured image data stored in the memory card 106a.

  The polarization filter effect adjustment processing unit 154 cooperates with the rotation processing unit 151 and the imaging processing unit 152 when capturing an image in the “polarization filter imaging mode”, and determines the rotation angle of the polarization filter 101b that maximizes the luminance value and Each image is taken at the specified rotation angle. Then, the polarization filter effect adjustment processing unit 154 calculates a difference between the two captured images, creates a difference image, and associates the difference with the image captured at the rotation angle at which the luminance value of the polarization filter 101b is maximized. Save to the memory card 106a. There may be a plurality of preset rotation angles. Further, information on the rotation angle of the polarizing filter 101b at the time of shooting is added to the shot image and stored in the memory card 106a. Information on the rotation angle of the polarizing filter 101b when an image based on the difference image is taken may be added and stored in the memory card 106a. Furthermore, images of the same subject captured in the “polarization filter imaging mode” are stored in the memory card 106a in association with each other.

  FIG. 2 is a diagram illustrating an example of the polarizing filter 101b. In FIG. 2A, the polarizing filter 101b is polarized in a state where the movable polarizing glass 300, the motor 301 for switching whether or not to insert the polarizing glass 300 into the optical path, and the polarizing glass 300 inserted in the optical path. A motor 302 for rotating the filter 101b around the optical axis, an encoder 303a for detecting the rotation angle, and an encoder 303b for detecting the reference angle of the polarizing filter 101b are provided. The motor 301 and the motor 302 are included in the drive unit 111. The encoder 303a and the encoder 303b are included in the angle detection unit 110.

  The motor 302 drives a gear 305 in which a gear 304 attached to a shaft is carved around the polarizing filter 101b. The ratio between the number of teeth of the gear 304 and the number of teeth of the gear 305 around the polarizing filter 101b is determined in advance. For example, the polarizing filter 101b rotates in proportion to the rotation angle of the motor 302.

  The encoder 303a detects the rotation angle of the motor 302. For example, when the resolution of the encoder 303a is 10 degrees, one rotation of the motor 302 can be detected with an accuracy of 1/36. As an example, when the number of teeth of the shaft gear 304 is 36, and the number of teeth of the shaft 305 and the gear 305 around the polarizing filter 101b is 360, when the motor 302 rotates 1/36, the polarizing filter 101b rotates once. When the motor 302 rotates 10 times, the polarizing filter 101b rotates 360 degrees. The encoder 303 has, for example, a plurality of detection mechanisms whose phases are shifted, and can determine the rotation direction of the polarizing filter 101b. For example, a stepping motor is used as the motor 301 and the motor 302, and the control unit 105 can accurately control the rotation angle of each motor.

  Here, the rotation angle of the polarizing filter 101b is detected as a rotation angle with respect to a predetermined reference angle. As shown in FIG. 2A, the reference angle is an angle of the polarizing filter 101b when the reference angle detection plate 306 is detected by the encoder 303b. In this embodiment, the reference angle is set to 0 degree. To do. For example, the control unit 105 rotates the polarizing filter 101b clockwise from the reference angle (0 degree) illustrated in FIG. 2B to change the polarization direction of the polarizing glass 300 to 45 degrees, 90 degrees, 135 degrees, and 180 degrees. The degree of polarization can be changed. FIG. 2C shows the state of the rotation angle of the polarizing glass 300 when the polarizing filter 101b is rotated 90 degrees from the reference angle.

  When the photographer manually rotates the polarizing filter 101b, the control unit 105 acquires the reference angle and the rotation angle of the polarizing filter 101b with the encoder 303a and the encoder 303b so that the motor 302 rotates idly. Alternatively, when the camera 100 rotates the polarizing filter 101b only manually, the motor 302 may be removed while leaving the encoder 303a. Further, when manually switching the presence / absence of the polarizing filter 101b, the motor 301 is also unnecessary.

  In this way, the camera 100 according to the present embodiment can detect the rotation angle of the polarizing filter 101b as the rotation angle with respect to the reference angle.

  FIG. 3 is a flowchart showing processing at the time of photographing in the “polarization filter photographing mode”.

  (Step S <b> 101) The control unit 105 moves the polarizing filter 101 b to the reference angle by the driving unit 111.

  (Step S <b> 102) The control unit 105 causes the imaging unit 102 or the photometry unit 112 to measure the luminance value of the subject image. Note that the luminance value may be measured by obtaining an average value of the luminance values of each pixel for the entire angle of view captured by the imaging unit 102 or a part of an image captured by the imaging unit 102 (for example, the angle of view). The average value of the luminance values of the center portion of the image, the specific subject set in advance, the autofocus area, etc.) may be obtained. In this case, a part for measuring the luminance value is designated in advance by using a setting menu of the operation unit 108 or the like.

  (Step S <b> 103) The control unit 105 acquires angle information of the polarizing filter 101 b by the angle detection unit 110.

  (Step S104) The control unit 105 associates the luminance value measured in step S102 with the angle information acquired in step S103, and holds it in the nonvolatile memory 109 or an internal register.

  (Step S105) The control unit 105 determines whether or not the cumulative angle with respect to the reference angle of the polarizing filter 101b (the angle with respect to the reference angle when rotated by a predetermined angle in step S106) is 180 degrees or more. The control unit 105 proceeds to the process of step S107 when the cumulative angle is 180 degrees or more, and proceeds to the process of step S106 when the cumulative angle is less than 180 degrees.

  (Step S106) The control unit 105 causes the drive unit 111 to rotate the polarizing filter 101b by a predetermined angle (for example, 5 degrees). Then, returning to the process of step S102, the control unit 105 repeatedly executes the same process until the cumulative angle with respect to the reference angle of the polarizing filter 101b becomes, for example, 180 degrees or more. The cumulative angle does not have to be 180 degrees.

  (Step S107) The control unit 105 refers to the photometric result for each angle of the polarizing filter 101b acquired in step S104, and obtains the angle (first rotation angle) of the polarizing filter 101b having the maximum luminance value.

  (Step S108) The control unit 105 causes the driving unit 111 to move the polarizing filter 101b to the first rotation angle. Then, the control unit 105 captures an image with the imaging unit 102, and captures image data of the captured image (first image) into the image buffer 103.

  (Step S109) The control unit 105 causes the driving unit 111 to move the polarizing filter 101b to a preset designated angle (second rotation angle). Then, the control unit 105 captures an image with the imaging unit 102, and captures image data of the captured image (second image) into the image buffer 103.

  (Step S <b> 110) The control unit 105 creates a difference image between the first image and the second image, and stores the difference image in the image buffer 103. The difference image is created by, for example, obtaining a difference between pixel values at the same angle for each color component of RGB (or for each signal of YCrCb). If no difference image is created at the time of shooting, the process of step S110 need not be performed.

  (Step S <b> 111) The control unit 105 includes information about the rotation angle of the polarization filter 101 b when the first image is captured in the image data of the first image held in the image buffer 103 (first rotation angle). Is stored in the memory card 106a. In addition, the control unit 105 may add the rotation angle information (second rotation angle) of the polarizing filter 101b when the second image is captured to the image data of the difference image and store the difference image image data in the memory card 106a. Good. Or when not performing the process of step S110, the control part 105 preserve | saves not the image data of a difference image but the image data of a 2nd image in the memory card 106a. At this time, the control unit 105 stores the image data of the first image and the image data of the difference image in association with each other in the memory card 106a. For example, the file association may be such that the file name of each image data is stored in the header of each image data, or the file name and attribute are made common so that the correspondence can be known. Alternatively, the image data of the difference image may be compressed and stored in the header portion of the image data of the first image. In any case, the control unit 105 only needs to be able to identify the corresponding difference image when reading the first image stored in the memory card 106a.

  Here, in the above description, the exposure condition is not particularly mentioned, but the luminance value of the image changes due to the effect of the polarizing filter 101b. For example, in step S108 and step S109, when an image is shot with automatic exposure, the exposure condition varies for each shot. Therefore, it is preferable to set the exposure condition based on the photometric result in step S102, and take the first image and the second image in step S108 and step S109 with the set fixed exposure condition. Thereby, since the exposure conditions can be fixed, the exposure conditions of the images taken at different rotation angles of the polarizing filter 101b are the same, so that the effect of the polarizing filter 101b can be easily adjusted after shooting. Note that the camera 100 according to the present embodiment sets the exposure condition based on the rotation angle of the polarizing filter 101b having the maximum luminance value. As a result, it is possible to avoid the occurrence of problems such as overexposure in images taken at other rotation angles. Alternatively, when the dynamic range of the camera 100 is wide, the exposure condition may be set with an arbitrary luminance value.

  In this way, the camera 100 according to the present embodiment is a difference image between the first image captured at the rotation angle at which the luminance value is maximized and the second image captured at the rotation angle specified in advance. And the image data of the first image and the image data of the difference image are associated with each other and stored in the memory card 106a. Note that information about the rotation angle of the polarizing filter 101b at the time of shooting is added to each image data and stored in the memory card 106a in association with each other.

  FIG. 4 is a diagram illustrating an example of the operation at the time of photographing described in FIG. Here, the rotation angle of the polarizing filter 101b specified in advance is 120 degrees. The rotation angle is set using a setting menu of the camera 100 or the like.

  In the example of FIG. 4, the control unit 105 performs photometry while rotating the polarizing filter 101b from 0 degrees to 180 degrees. Then, the control unit 105 detects the rotation angle of the polarization filter 101b having the maximum luminance value (45 degrees in the example of FIG. 4). Then, the control unit 105 captures the image IMGa at a rotation angle (45 degrees) at which the luminance value is maximized with the polarizing filter 101b. Further, the control unit 105 captures the image IMGb with the polarization filter 101b at a specified rotation angle of 120 degrees. In addition, the control unit 105 obtains a difference between the image IMGa and the image IMGb and creates a difference image IMGs. Then, the control unit 105 stores the image IMGa and the difference image IMGs in the memory card 106a. At this time, the file name, the shooting date and time, the angle of the polarizing filter 101b at the time of shooting, the luminance information, the file name of the related difference image (for example, IMGs), and the like are added to the header of the image data of the image IMGa. 106a. On the other hand, in the header of the image data of the difference image IMGs, the file name, the shooting date and time, the angle (120 degrees) of the polarization filter 101b when the original image of the difference image was shot, and the angle (45 degrees-120) from which the difference was obtained. The file name of the related image (for example, the image IMGa of the maximum luminance value) and the like are added and stored in the memory card 106a. The information added to the image data may be a part of the information given in the above example, or other information may be added. For example, in this embodiment, the rotation angle information of the polarizing filter 101b is described as angle information. However, the number of rotations of the motor 302, the value of the encoder 303a, and the like may be added to the image data as rotation angle information.

  As a result, when the control unit 105 reads the image data of the image IMGa from the memory card 106a, the control unit 105 recognizes that the image is an image of the maximum brightness, which is an image captured at a rotation angle of 45 degrees of the polarizing filter 101b. . Further, it can be seen that the file name of the difference image related to IMGa is IMGs. Note that FIG. 4 is an example, and the image data of the difference image IMGs may be compressed and stored in the header of the image IMGa, or the two image data may be associated by other general methods. Further, the format of the image data corresponds to, for example, the Exif standard, and information on the rotation angle with respect to the reference angle of the polarization filter 101b is stored in the header portion of the image data together with the file name and the shooting date and time. Here, the rotation angle information may be angle information or a predetermined code corresponding to the angle. Alternatively, the rotation angle information may be the rotation number of the motor 302 or an output value of the encoder 303b. In either case, it is only necessary to know the angle of the polarization filter 101b of the captured image.

  Next, an example in which captured image data stored in the memory card 106a is read out and displayed on the display unit 107 to adjust the effect of the polarizing filter 101b will be described.

  The user reads the captured image data stored in the memory card 106a, and when the image displayed on the display unit 107 is an image captured in the “polarization filter imaging mode”, the effect of the polarization filter 101b is obtained. Can be adjusted.

  FIG. 5A shows a screen example of the display unit 107 when the user activates the “polarization filter effect adjustment function” by the operation unit 108 during reproduction of the image IMGa.

  In the example of FIG. 5A, the image IMGa and the image IMGc when the filter effect of the image IMGa is adjusted are displayed side by side. An adjustment bar 201 for adjusting the filter effect is displayed on the screen of the display unit 107. The adjustment bar 201 can be freely set between a rotation angle of 45 degrees and 120 degrees of the polarizing filter 101b by a user operation. Can be moved. When the user wants to set the filter effect to a rotation angle of 90 degrees, for example, the user may drag the adjustment bar 201 to a position of 90 degrees while touching the adjustment bar 201 on the touch panel. Here, the rotation angle of 45 degrees is the rotation angle of the polarization filter 101b of the image IMGa photographed at the maximum brightness, and the rotation angle of 120 degrees is a difference image (see FIG. 5) stored in the memory card 106a in association with the image IMGa. In the example of 4, the rotation angle of the polarizing filter 101b when the image IMGb when the IMGs) is created is taken. Then, the control unit 105 adjusts the filter effect of the image IMGa according to the position of the adjustment bar 201 and displays the adjusted image IMGc. If the user likes the adjustment result, the user can touch the save button 202 to save the image IMGc after adjusting the filter effect in the memory card 106a. When the user wants to further adjust the filter effect, the user repeats the same operation. When the “polarization filter effect adjustment function” is to be ended, the user touches the end button 203.

  In FIG. 5A, the filter effect can be adjusted between the maximum brightness rotation angle 45 degrees stored in the memory card 106a and the specified rotation angle 120 degrees. As shown in b), a rotation angle (such as 0 to 180 degrees) other than the angle at which the maximum luminance is specified and the designated angle may be selected. 5A and 5B, the filter effect is adjusted to the rotation angle of the polarization filter 101b according to the position of the adjustment bar 201. However, the rotation angle of the polarization filter 101b is directly set to a numerical value. May be displayed on the display unit 107 and specified as “angle: 80 degrees”, for example.

  Next, a method for adjusting the filter effect will be described with reference to FIG. FIG. 6A is a diagram showing a calculation process when creating the difference image IMGs described in FIG. In FIG. 6A, the difference image IMGs is obtained by subtracting an image IMGb photographed at a specified angle from an image IMGa photographed at a rotation angle with the maximum luminance.

  FIG. 6B is a diagram showing calculation processing when creating the image IMGc after adjusting the filter effect described in FIG. In FIG. 6B, the image IMGc after the filter effect adjustment is created using the maximum brightness image IMGa stored in the memory card 106a and the difference image IMGs stored in association with the image IMGa. . For example, in FIG. 6B, the image IMGc after the filter effect adjustment is obtained by subtracting an image obtained by multiplying the difference image IMGs by the coefficient α from the image IMGa having the maximum luminance. Here, the coefficient α varies depending on the rotation angle of the polarizing filter 101b for which the filter effect is to be adjusted. For example, in the example of FIG. 5A, the coefficient α is 0 when the angle is 45 degrees at which the maximum luminance is achieved, and is 1 when the specified angle is 120 degrees. In this case, in FIG. 6B, when the coefficient α is 0, the adjusted image IMGc = maximum luminance image IMGa, and when the coefficient α is 1, the adjusted image IMGc = specified angle image IMGb. The coefficient α may be linearly changed in proportion to the movement of the adjustment bar 201 between the maximum luminance angle of 45 degrees and the specified angle of 120 degrees, or may be changed in a curved line. In the example of FIG. 5B, the coefficient α varies from 0 degrees to 180 degrees, but 45 degrees is the angle at which the maximum luminance is reached, so the coefficient α of 0 degrees is set to the same value as the coefficient α of 90 degrees. Thus, the change in the coefficient α from 45 degrees to 90 degrees may be reversed to obtain the change in the coefficient α from 0 degrees to 45 degrees. Note that the change from 120 degrees to 180 degrees may be interpolated on the assumption that 0 degrees and 180 degrees have the same coefficient α. Or you may interpolate so that it may return | fold at the intermediate angle 135 degree | times different only 90 degree | times from the angle used as the maximum brightness | luminance. Alternatively, the difference image IMGs may be created by obtaining an angle at which the minimum luminance is obtained at the time of shooting and setting the specified angle to the minimum luminance angle. In this case, the coefficient α changes between the maximum luminance angle and the minimum luminance angle.

  The coefficient α is multiplied for each pixel of the entire screen constituting the difference image, but pixels in a preset area (for example, a central portion of the angle of view, a preset specific subject, an autofocus area, etc.) You may make it multiply only. Alternatively, the coefficient α for multiplying a preset area and the coefficient α for multiplying other areas may be set to different values. Furthermore, the value of the coefficient α may be gradually changed radially from a specific position (center, etc.) on the screen.

  FIG. 7 is a flowchart showing the flow of processing in the “polarization filter effect adjustment function”. Note that the flowchart of FIG. 7 shows processing when the user selects a captured image and activates the “polarization filter effect adjustment function”. FIG. 5A shows an example of a screen when the “polarization filter effect adjustment function” is activated. Hereinafter, the flowchart of FIG. 7 will be described in order with reference to FIG.

  (Step S201) The control unit 105 reads the image data of the image selected by the user from the memory card 106a. At this time, the image data of the difference image stored in association with the image data is also read. Each image data read from the memory card 106 a is held in the image buffer 103.

  (Step S202) The control unit 105 displays an image read from the memory card 106a on the display unit 107. In the example of FIG. 5A, the maximum brightness image IMGa is read from the memory card 106 a and displayed on the display unit 107.

  (Step S203) The control unit 105 determines whether or not the angle of the polarizing filter 101b has been adjusted by a user operation. For example, in the case of FIG. 5A, the control unit 105 determines whether or not the position of the adjustment bar 201 has been moved by a user operation. The control unit 105 proceeds to the process of step S204 when the angle adjustment is performed, and proceeds to the process of step S207 when the angle adjustment is not performed. In FIG. 5A, the initial position of the adjustment bar 201 is set to the specified angle (120 degrees), and the image IMGb having the specified angle shown in FIG. 6A is displayed on the filter effect adjustment image IMGc. Good.

  (Step S204) The control unit 105 calculates the coefficient α according to the position of the adjustment bar 201 moved by the user operation. The calculation of the coefficient α is as described above.

  (Step S205) The control unit 105 uses the coefficient α calculated in step S204 to create an image IMGc with the filter effect adjusted, as will be described with reference to FIG.

  (Step S <b> 206) The control unit 105 displays the image after the filter effect adjustment on the display unit 107. For example, in the case of FIG. 5A, the filter effect adjustment image IMGc is displayed on the display unit 107. And the control part 105 returns to the process of step S203.

  (Step S207) The control unit 105 determines whether or not the save button 202 shown in FIG. If the save button 202 is pressed, the process proceeds to step S208. If the save button 202 is not pressed, the process proceeds to step S209.

  (Step S208) The control unit 105 stores the image data of the image with the adjusted filter effect in the memory card 106a. For example, in the case of FIG. 5A, the image data of the filter effect adjustment image IMGc is stored in the memory card 106a. Note that, when storing the image data of the adjusted image IMGc, as described with reference to FIG. 4, information for associating the image IMGa may be added to the header of the image data. Further, the rotation angle information of the polarizing filter 101b at the time of adjustment may be added to the header of the image data, or the coefficient α may be added.

  (Step S209) The control unit 105 determines whether or not the end button 203 shown in FIG. If the end button 203 has not been pressed, the process returns to step S203. If the end button 203 has been pressed, the filter effect adjustment process ends.

  In this way, the camera 100 according to the present embodiment can adjust the effect of the polarizing filter after shooting.

  In the above-described embodiment, the difference image from the image captured at the specified angle is created based on the image captured at the rotation angle of the polarization filter 101b having the maximum luminance value. Two or more images having different rotation angles may be taken, and the difference images may be stored in association with each other. Alternatively, instead of the difference image, two or more images having different rotation angles of the polarizing filter 101b may be stored as they are associated with each other, and the difference image may be created when the filter effect is adjusted later. Alternatively, the specified angle may be set at two or more locations, an image may be taken, and a difference image from the image with the maximum luminance angle may be created for each of the images with a plurality of specified angles. The filter effect can be adjusted with higher accuracy as the number of difference images having different rotation angles of the polarizing filter 101b increases.

  As described above, the camera according to the present invention has been described by way of example in the embodiment, but can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The present invention is defined by the claims, and the present invention is not limited to the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Camera; 101 ... Lens part; 101a ... Optical lens; 101b ... Polarizing filter; 102 ... Imaging part; 103 ... Image buffer; 104 ... Image processing part; ... Control unit; 106 ... Memory card IF; 106a ... Memory card; 107 ... Display unit; 108 ... Operation unit; 109 ... Non-volatile memory; 111 ... Drive unit; 112 ... Photometry unit; 151 ... Rotation processing unit; 152 ... Shooting processing unit; 153 ... Reproduction processing unit; 154 ... Polarization filter effect adjustment processing unit; 201 ... Adjustment bar; 300 ... Polarized glass; 301, 302 ... Motor; 303a, 303b ... Encoder; 304, 305 ... Gear

Claims (8)

A polarizing filter that includes an optical axis of an optical lens and is rotatable on a rotation axis parallel to the optical axis;
Photographing means for photographing an image through the optical lens and the polarizing filter;
Detecting means for detecting a rotation angle with respect to a reference angle of the polarizing filter;
Photometric means for measuring a luminance value of light incident through the optical lens and the polarizing filter;
A first rotation angle of the polarizing filter that maximizes the luminance value measured by the photometric means is obtained, and a first image taken by the imaging means at the first rotation angle of the polarizing filter that maximizes the luminance value. A difference image is obtained by obtaining a difference between the first image and a second image photographed by the photographing means at a second rotation angle of the polarization filter specified in advance, and the first image and the difference And a control unit that records the image on a storage medium in association with the image. The camera of claim 1,
The control means reads the first image and the difference image recorded in the storage medium, and creates an image obtained by subtracting the difference image obtained by multiplying a preset coefficient from the first image. Camera characterized by. The camera according to claim 1 or 2,
The second rotation angle of the polarizing filter designated in advance is an angle rotated by 180 degrees with respect to the first rotation angle of the polarizing filter having the maximum luminance value. . The camera according to any one of claims 1 to 3,
Further provided is a driving means for rotating the polarizing filter,
The camera is characterized in that the control means rotates the polarizing filter by the driving means and takes the first image and the second image by the photographing means. The camera according to any one of claims 1 to 4,
The camera is characterized in that the first image and the second image are shot under a preset fixed exposure condition. The camera according to claim 5, wherein
The camera is characterized in that the control means sets an exposure condition at the first rotation angle of the polarizing filter that maximizes the luminance value measured by the photometry means as the fixed exposure condition. The camera according to claim 6, wherein
The photometric means further includes a designation means for designating an area for photometry,
The control means measures the brightness value of the designated area by the photometry means, and sets an exposure condition at the first rotation angle of the polarizing filter that maximizes the brightness value of the designated area. A camera that is set as a fixed exposure condition. The camera according to claim 6 or 7,
The camera, wherein the photometric means measures the luminance value using an image photographed in real time by the photographing means.

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