JP5217783B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus.

2. Description of the Related Art Conventionally, a phenomenon is known in which a dark portion gradation of image data is darkened by photographing a subject having a large luminance difference. Therefore, in the invention of Patent Document 1, the tone is compressed by increasing the gain of the dark portion gradation, and the blackening of the dark portion gradation is improved.
Japanese Patent No. 2663189

  However, in the invention of Patent Document 1 described above, with the above-described gradation compression, there is a problem that the impression of brightness is different between an image that has been subjected to gradation compression and an image that has not been subjected to gradation, and the user feels uncomfortable, There is a problem in that the contrast decreases with gradation compression. Therefore, a technique to change the exposure conditions at the time of shooting according to gradation compression is considered, but for users with little knowledge and experience, it may be difficult to make appropriate settings, and gradation compression is effective. It may not be available.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an imaging apparatus that allows a user to appropriately perform settings related to correction of dark area gradation.

  An image pickup apparatus according to the present invention improves an image pickup unit that picks up an image of a subject and generates an image, a setting unit that sets a control value related to the brightness of the image, and brightness of a dark portion gradation of image data of the image A correction unit that performs correction, and a control unit that changes the control value and the correction condition by the correction unit in association with each other and generates a plurality of images including at least two images having different correction conditions.

  The setting unit includes at least one of an exposure amount at the time of image capturing by the image capturing unit, a tone conversion characteristic when performing a tone conversion process on the image generated by the image capturing unit, and sensitivity as the control value. One may be set.

  The plurality of images may include an image that has been corrected by the correction unit and an image that has not been corrected by the correction unit.

  The plurality of images may include a plurality of images having the same control value and different correction conditions.

  A control unit configured to receive a user designation related to at least one of the control value and the correction condition, wherein the control unit has a predetermined change width and the control value and the correction condition based on the content of the user designation; The plurality of images may be generated by changing them in association with each other.

  The control unit may determine the change width based on characteristics of the image generated by the imaging unit.

  Further, the control unit may determine the change width based on at least one of a type of a main subject of the image generated by the imaging unit, a characteristic related to a color tone, and a characteristic related to contrast.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which a user can perform appropriately the setting regarding correction | amendment of a dark part gradation can be provided.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the first embodiment, a single lens reflex type electronic camera will be described as an example of the camera of the present invention.

  FIG. 1 is a diagram illustrating a configuration of an electronic camera 1 according to the first embodiment. As shown in FIG. 1, an electronic camera 1 includes a photographing lens 2, an aperture 3, a quick return mirror 4, a sub mirror 5, a diffusion screen 6, a condenser lens 7, a pentaprism 8, a beam splitter 9, an eyepiece lens 10, and an imaging lens. 11, a photometric sensor 12, a shutter 13, an image sensor 14, and a focus detection unit 15.

  The imaging element 14 is a semiconductor device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). For example, the focus detection unit 15 detects a focus state of the photographic lens 2 by performing phase difference type focus detection. The electronic camera 1 detects the focus state of the photographic lens 2 by performing contrast-type focus detection based on the luminance detected by the photometric sensor 12.

  The electronic camera 1 further includes a monitor 16 such as a liquid crystal monitor that displays an image generated by imaging, and a control unit 17 that controls each unit. The control unit 17 includes a memory (not shown) therein, and records a program for controlling each unit in advance.

  When not photographing, that is, when photographing is not performed, the quick return mirror 4 is disposed at an angle of 45 ° as shown in FIG. The light beam that has passed through the photographing lens 2 and the diaphragm 3 is reflected by the quick return mirror 4 and guided to the eyepiece lens 10 through the diffusion screen 6, the condenser lens 7, the pentaprism 8, and the beam splitter 9. The user confirms the composition by viewing the subject image through the eyepiece 10. On the other hand, the light beam split upward by the beam splitter 9 is re-imaged on the imaging surface of the photometric sensor 12 via the imaging lens 11. Further, the light beam transmitted through the quick return mirror 4 is guided to the focus detection unit 15 via the sub mirror 5.

  On the other hand, at the time of photographing, the quick return mirror 4 is retracted to the position indicated by the broken line, the shutter 13 is opened, and the light flux from the photographing lens 2 is guided to the image sensor 14.

  FIG. 2 is a functional block diagram of the electronic camera 1 according to the first embodiment. 2, the electronic camera 1 includes a timing generator 20, a signal processing unit 21, an A / D conversion unit 22, a buffer memory 23, a bus 24, a card interface 25, and a compression / decompression unit in addition to the configuration of FIG. 26, each part of the image display unit 27 is provided. The timing generator 20 supplies output pulses to the image sensor 14. The image data generated by the image sensor 14 is temporarily stored in the buffer memory 23 via the signal processing unit 21 (including a gain adjustment unit corresponding to the imaging sensitivity) and the A / D conversion unit 22. The buffer memory 23 is connected to the bus 24. The bus 24 is connected to the card interface 25, the control unit 17, the compression / decompression unit 26, and the image display unit 27 described in FIG. The card interface 25 is connected to a removable memory card 28 and records image data on the memory card 28. The control unit 17 is connected to a switch group 29 (including a release button (not shown)) of the electronic camera 1, a timing generator 20, and a photometric sensor 12. Further, the image display unit 27 displays an image or the like on the monitor 16 provided on the back surface of the electronic camera 1.

  The electronic camera 1 also includes a gradation non-compression mode that does not correct dark part gradation of image data, and a gradation compression mode that performs dark part gradation correction. Which mode is used for shooting may be selected in advance by the user via the switch group 29 or may be automatically selected by the control unit 17. In the gradation compression mode, the gradation compression amount (brightness improvement amount) can be set in three levels (High / Normal / Low), and the electronic camera 1 automatically determines the gradation compression amount. Auto can also be set. These settings are also made in advance by the user via the switch group 29. Furthermore, the electronic camera 1 includes a bracketing function for generating a plurality of images having different gradation compression amounts in the gradation compression mode. Settings relating to the bracketing function are also performed by the user via the switch group 29. Details of the bracketing function will be described later.

  The operation at the time of photographing of the electronic camera 1 having the above-described configuration will be described using the flowchart shown in FIG.

  In step S <b> 1, the control unit 17 determines whether or not the user has instructed to start shooting via the switch group 29. If the control unit 17 determines that an instruction to start photographing is given, the process proceeds to step S2.

  In step S <b> 2, the control unit 17 controls each unit and captures a subject image with the image sensor 14 to generate image data. Image data generated by the imaging device 14 is temporarily stored in the buffer memory 23 via the signal processing unit 21 and the A / D conversion unit 22.

  In step S3, the control unit 17 reads the image data from the buffer memory 23 and performs normal image processing. Normal image processing includes white balance adjustment, interpolation processing, color tone correction processing, and the like. Since the specific method of each process is the same as that of a well-known technique, description is abbreviate | omitted.

  In step S4, the control unit 17 performs gradation conversion processing on the image data subjected to the image processing in step S3 according to the gradation curve G. The details of the gradation conversion process are the same as those of the known technique, and thus description thereof is omitted. Then, the control unit 17 proceeds to step S5. Note that the gradation curve G has, for example, the characteristics shown in FIG.

  In step S5, the control unit 17 determines whether or not the gradation compression mode is set. If the controller 17 determines that the gradation compression mode is set, the process proceeds to step S6. On the other hand, if it is determined that the gradation compression mode is not set (the gradation non-compression mode is set), the control unit 17 proceeds to step S10 described later.

  In step S6, the control unit 17 determines whether or not the Auto mode is set. If the control unit 17 determines that the Auto mode is set, the control unit 17 proceeds to Step S8 described later. On the other hand, if it is determined that the Auto mode is not set (any mode of High / Normal / Low is set), the control unit 17 proceeds to step S7.

  In step S7, the control unit 17 performs a gradation compression process on the image data that has been subjected to the gradation conversion process in step S4.

FIG. 5 is a diagram showing the gradation compression parameter fg. The parameter fg has a gain corresponding to the brightness Y of the image as shown in FIG. The parameter fg increases as the brightness Y decreases (as the neighborhood including the processing pixel becomes darker). On the contrary, the parameter fg approaches 1 as the brightness Y increases (the neighborhood range including the processing pixel is brighter). Note that F _{H in} FIG. 5 represents a parameter fg when the gradation compression amount is “High”, and F _N is a parameter when the gradation compression amount is “Normal”. indicates fg, F _L is a parameter of fg when the magnitude of the gradation compression amount is "Low".

  The gradation compression calculation in each pixel R [x, y], G [x, y], B [x, y] is performed by the following equations 1 to 4.

Y in Equation 1 indicates the luminance value of the target pixel. Further, kr, kg, and kb in Equation 1 are predetermined coefficients. Further, Lpw in Expressions 2 to 4 is a low-pass filter around the pixel of interest, and this low-pass filter has the characteristics shown in FIG. Further, fg in Expressions 2 to 4 corresponds to the parameter fg described above. That is, when the gradation compression amount specified by the user is “High”, fg = F _H , and when the gradation compression amount specified by the user is “Normal”. Fg = F _N , and when the gradation compression amount designated by the user is “Low”, fg = F _L. When the gradation compression process is completed, the control unit 17 proceeds to step S10 described later.

  If it is determined in step S6 that the Auto mode is set, in step S8, the control unit 17 determines the gradation compression amount. For example, the control unit 17 divides the image data generated in step S2 into a plurality of areas, obtains a luminance difference between the maximum luminance area and the minimum luminance area, and determines the gradation compression amount according to the luminance difference. To do. Note that the gradation compression amount may be determined according to the contrast of the bright part. Further, the configuration may be such that the gradation compression amount is determined according to the shooting mode (for example, “portrait mode”, “landscape mode”, etc.), or the gradation compression amount is determined according to the contrast strength. Alternatively, the gradation compression amount may be determined according to the image adjustment mode. Further, the gradation compression amount may be determined according to the image determination result by scene analysis or face recognition. Note that the control unit 17 may select one of the parameters fg from the three parameters fg (FIG. 5) described in step S7 when determining the gradation compression amount, and the parameters fg An appropriate parameter fg may be determined by a calculation based on the calculation.

  In step S9, the control unit 17 performs a gradation compression process on the image data subjected to the gradation conversion process in step S4 according to the gradation compression amount determined in step S8. Details of the gradation compression processing are the same as in step S7.

  In step S10, the control unit 17 sends the image data subjected to the gradation compression process in step S8 or step S9 or the image data subjected to the gradation conversion process in step S4 to the memory card 28 via the card interface 25. Record and finish a series of processing. Note that before the image data is recorded on the memory card 28, an image compression process (such as a JPEG compression process) may be performed as necessary via the compression / decompression unit 26.

  In the example of FIG. 3, in the Auto mode, the gradation compression amount is determined in step S8, and gradation compression processing is performed in step S7 according to the determined gradation compression amount. However, in the Auto mode, a configuration may be adopted in which tone compression processing is performed with a plurality of tone compression amounts, and a plurality of images after tone compression processing are analyzed to determine an optimum tone compression amount.

  Next, the bracketing function in the gradation compression mode will be described. The bracketing function is a function for generating a plurality of images with different gradation compression amounts in one shooting. By confirming the plurality of images, the user can appropriately perform settings related to the gradation compression processing such as the optimum gradation compression amount.

  The bracketing function is set by, for example, displaying a menu related to bracketing on the monitor 16 and operating the switch group 29 while the user looks at the menu. In addition to the bracketing in the gradation compression mode, the menu related to bracketing may include known AE (automatic exposure) bracketing, white balance bracketing, and the like as options.

  The operation at the time of shooting of the electronic camera 1 when the bracketing function in the gradation compression mode is set will be described with reference to the flowchart shown in FIG.

  In step S <b> 21, the control unit 17 accepts user designation regarding bracketing in the gradation compression mode. The control unit 17 controls the image display unit 27 to display, for example, a bracketing setting screen shown in FIG. In the example of FIG. 8, a setting screen for designating the number of bracketing and the gradation compression mode is illustrated. Note that the number of bracketing sheets may be a predetermined number without being settable. An upper limit may be set for the number of bracketing sheets that can be set. As for the gradation compression mode, any one mode may be selected, or a plurality of modes may be selected.

  In step S <b> 22, the control unit 17 determines whether or not the user has instructed to start shooting via the switch group 29. If the control unit 17 determines that an instruction to start shooting is given, the process proceeds to step S23.

  In step S23 to step S25, the control unit 17 performs the same processing as in step S2 to step S4 in the flowchart of FIG.

  In step S26, the control unit 17 determines a plurality of tone compression amounts based on the user designation received in step S21. The control unit 17 determines a plurality of gradation compression amounts according to at least one of the following A) to C).

A) Gradation compression amount for comparison = 0 (that is, gradation compression processing is not performed) is combined to determine a plurality of gradation compression amounts. The control unit 17 determines the gradation specified by the user in step S21. The gradation compression amount of the compression mode (each gradation compression amount when a plurality of gradation compression modes is designated) and the gradation compression amount = 0 are determined.

  The gradation compression amount is determined in the same manner as the processing described with reference to the flowchart of FIG.

B) A plurality of gradation compression amounts are determined with a predetermined width on the basis of the gradation compression mode designated by the user. For example, any one parameter fg from the three parameters fg (FIG. 5) described in step S7. May be selected. For example, if the Nomal mode is specified, in addition to F _H is fg parameter for Nomal, selects a low F _L gradation compression amount greater than F _H and Nomal gradation compression amount than Nomal . Further, an appropriate parameter fg may be determined by calculation based on the three parameters fg described in step S7. For example, when the Normal mode is designated, in addition to the Fg parameter for Normal, F _H , the parameter F ₊ whose tone compression amount is larger than the Normal by a predetermined width, and the tone compression amount is set to a predetermined value than the Normal. The parameter F ₋ having a smaller width may be obtained by calculation. Further, the bracketing direction may be changed in the vertical direction based on a certain parameter fg, or the change width may be distributed in one direction. Moreover, you may combine both.

C) The change width of the gradation compression amount based on the gradation compression mode designated by the user is automatically determined, and a plurality of gradation compression amounts are determined based on the determined change width. The type of main subject in the image to be processed, characteristics relating to color tone, characteristics relating to contrast, and the like are conceivable. These factors are factors related to the ease of gradation compression processing and the deterioration of image quality due to gradation compression processing.

  For example, when the main subject is a person, the gradation compression process is relatively effective, and noise is easily noticeable due to the gradation compression process. Therefore, when the main subject is a person, it is preferable to make the change width of the gradation compression amount relatively narrow so that the difference in the small change width can be confirmed. On the other hand, when the main subject is not a person, the gradation compression process is relatively ineffective, so the effect of the gradation compression process is difficult to understand, and noise is not noticeable due to the gradation compression process. Therefore, when the main subject is not a person, it is preferable to make the change range of the gradation compression amount relatively wide so that the difference in the large change range can be confirmed.

  In addition, when the characteristics relating to the color tone are vivid, such as the so-called Vivid mode, the gradation compression process is relatively effective, and noise is easily noticeable by the gradation compression process. Therefore, it is preferable to make the change width of the gradation compression amount relatively narrow so that the difference in the small change width can be confirmed as the characteristic relating to the color tone is brighter. On the other hand, when the characteristics relating to the color tone are not vivid, the gradation compression process is relatively ineffective, so the effect of the gradation compression process is difficult to understand, and noise is not noticeable due to the gradation compression process. Therefore, when the characteristics relating to the color tone are not vivid, it is preferable to make the change width of the gradation compression amount relatively wide so that the difference in the large change width can be confirmed.

  Further, as the contrast is larger, the gradation compression process is relatively effective, and noise is more noticeable due to the gradation compression process. Therefore, it is preferable that the change width of the gradation compression amount is narrowed and the difference in the small change width can be confirmed as the contrast is larger. On the other hand, the smaller the contrast is, the more difficult the gradation compression process is to be effective, so the effect of the gradation compression process is difficult to understand, and the noise is not noticeable due to the gradation compression process. Therefore, it is preferable that the smaller the contrast is, the wider the range of change in the gradation compression amount is, so that the difference in the large range of change can be confirmed.

  A plurality of gradation compression amounts may be determined by combining two or more methods among A) to C). Further, the method for determining a plurality of gradation compression amounts may be changed according to a predetermined number of bracketing sheets or a number of bracketing sheets designated by the user.

  In step S27, the control unit 17 performs a gradation compression process on the image data subjected to the gradation conversion process in step S25 according to the gradation compression amount determined in step S26. Details of the gradation compression processing are the same as in step S7. The control unit 17 performs a plurality of gradation compression processes according to the plurality of gradation compression amounts determined in step S26, generates a plurality of images, and ends the series of processes.

  As described above, according to the first embodiment, a plurality of images including at least two images having different dark part gradation correction conditions in the gradation compression process are generated. Therefore, the user can appropriately perform the setting related to the correction of the dark portion gradation by using these images for confirmation or the like.

  In particular, according to the first embodiment, by generating an image that has been subjected to the gradation compression process and an image that has not been subjected to the gradation compression process, the effect of dark part gradation correction is presented to the user in an easily understandable manner. can do.

  In the first embodiment, the case where the number of bracketing and the gradation compression mode can be designated as the user designation regarding the bracketing in the gradation compression mode has been described as an example. However, the present invention is not limited to this example. It is not limited. For example, the bracketing direction and the bracketing width may be specified by the user.

Second Embodiment
The second embodiment of the present invention will be described below with reference to the drawings. Since the second embodiment is a modification of the first embodiment, only portions different from the first embodiment will be described.

  The electronic camera of the second embodiment has the same configuration as the electronic camera 1 (see FIGS. 1 and 2) described in the first embodiment. Therefore, illustration and description of the configuration of the electronic camera of the second embodiment are omitted, and the following description will be made using the same reference numerals as those of the first embodiment.

  The electronic camera 1 of the second embodiment changes the exposure amount at the time of imaging in conjunction with the gradation compression amount.

  FIG. 9 will be described with reference to a flowchart showing an operation at the time of photographing of the electronic camera 1 of the second embodiment.

  In step S <b> 31, the control unit 17 determines whether or not the user has instructed to start shooting via the switch group 29. If the control unit 17 determines that an instruction to start photographing is given, the process proceeds to step S32.

  In step S32, the control unit 17 determines an exposure condition according to a gradation compression mode designated in advance. The exposure condition is determined in advance as an exposure correction amount for each gradation compression mode, for example, as shown in FIG. As shown in the example of FIG. 10, the exposure correction amount is determined in advance so as to suppress exposure as the gradation compression amount increases. An arithmetic expression for calculating the exposure correction amount may be prepared according to the gradation compression amount, and the exposure correction amount may be calculated each time according to the arithmetic expression. When the Auto mode is selected, for example, a tone compression amount is determined by using a through image, and an exposure condition is determined according to the tone compression amount.

  In step S <b> 33, the control unit 17 controls each unit, captures a subject image with the image sensor 14, and generates image data. At this time, the control unit 17 performs imaging according to the exposure condition determined in step S32. Image data generated by the imaging device 14 is temporarily stored in the buffer memory 23 via the signal processing unit 21 and the A / D conversion unit 22.

  In step S34 to step S41, the control unit 17 performs the same processing as in step S3 to step S10 in the flowchart of FIG.

  In the example of FIG. 9, in the Auto mode, the gradation compression amount is determined in step S39, and the gradation compression processing is performed in step S40 according to the determined gradation compression amount. However, in the Auto mode, a configuration may be adopted in which tone compression processing is performed with a plurality of tone compression amounts, and a plurality of images after tone compression processing are analyzed to determine an optimum tone compression amount.

  Next, the bracketing function in the gradation compression mode will be described. Since the contents and settings of the bracketing function are the same as those in the first embodiment, description thereof will be omitted.

  The operation at the time of shooting of the electronic camera 1 when the bracketing function in the gradation compression mode is set will be described with reference to the flowchart shown in FIG.

  In step S51, the control unit 17 accepts user designation regarding bracketing in the gradation compression mode, as in step S1 of the flowchart of FIG.

  In step S <b> 52, the control unit 17 determines whether the user has instructed to start shooting via the switch group 29. If the control unit 17 determines that an instruction to start photographing is given, the process proceeds to step S53.

  In step S53, the control unit 17 determines a plurality of gradation compression amounts and a plurality of exposure conditions. First, the control unit 17 determines a plurality of gradation compression amounts as in step S26 of the flowchart of FIG. Next, the control unit 17 determines an exposure condition for each of the determined plurality of gradation compression amounts in the same manner as Step S32 in the flowchart of FIG. As a result, a plurality of exposure conditions are determined.

  In step S <b> 54, the control unit 17 controls each unit and captures a subject image with the image sensor 14 to generate image data. At this time, the control unit 17 performs imaging according to any of the plurality of exposure conditions determined in step S53. Image data generated by the imaging device 14 is temporarily stored in the buffer memory 23 via the signal processing unit 21 and the A / D conversion unit 22.

  In step S55, the control unit 17 determines whether imaging has been completed under all the exposure conditions determined in step S53. If the control unit 17 determines that imaging has been completed, the process proceeds to step S57 to be described later. If it is determined that imaging has not been completed, the control unit 17 proceeds to step S56.

  In step S56, the control unit 17 changes the exposure condition by selecting an exposure condition that has not yet been imaged among all the exposure conditions determined in step S53, and returns to step S54.

  It should be noted that at the time when imaging is completed under all the exposure conditions determined in step S53 (YES in step S55), the same number of images as the number of exposure conditions determined in step S53 are generated.

  In Step S57 and Step S58, the control unit 17 performs the same processing as Step S34 and Step S35 in the flowchart of FIG.

  In step S59, similarly to step S27 in the flowchart of FIG. 7, the control unit 17 performs gradation compression on the image data subjected to the gradation conversion processing in step S58 according to the gradation compression amount determined in step S53. Process. Details of the gradation compression processing are the same as in step S7. The control unit 17 performs a plurality of gradation compression processes according to the plurality of gradation compression amounts determined in step S53, and generates a plurality of images.

  In step S60, the control unit 17 determines whether or not processing has been performed for all the images generated by the repeated imaging in step S54. When determining that the processing is not performed, the control unit 17 sets an image that has not been processed yet as a processing target, and returns to step S57. On the other hand, if it determines with having processed about all the produced | generated images, the control part 17 will complete | finish a series of processes.

  As described above, according to the second embodiment, the exposure condition, which is a control value related to the brightness of an image, and the gradation compression amount, which is a correction condition for performing correction to improve the brightness of the dark area gradation, are obtained. A plurality of images including at least two images having different correction conditions are generated in association with each other. Therefore, as in the first embodiment, the user can appropriately perform settings related to the correction of the dark portion gradation by using these images for confirmation and the like.

  In particular, according to the second embodiment, by generating a plurality of images with the same exposure conditions and different gradation compression amounts, it is possible to easily show the effect of dark portion gradation correction with exposure correction to the user. it can.

  In the second embodiment, as in the first embodiment, the bracketing direction, the bracketing width, and the like may be designated by the user as user designation regarding bracketing in the gradation compression mode. Furthermore, it is good also as a structure which receives the user specification regarding exposure conditions.

  For example, the direction in which the exposure condition is changed may be specified by the user. In the second embodiment, the example in which the exposure correction amount is determined in advance so as to suppress the exposure as the gradation compression amount increases is shown. However, the exposure correction amount is set as the gradation compression amount increases according to the user designation. You may make it predetermine so that it may enlarge.

  In the second embodiment, an example is shown in which the exposure correction amount for each gradation compression mode is determined in advance. However, this relationship may be designated by user designation. For example, when the main subject is a person, the effect of exposure correction is easily produced, and noise is easily noticeable by exposure correction. Therefore, when the main subject is a person, it is preferable to make the change range of exposure correction relatively narrow so that the difference can be confirmed with a small change range. On the other hand, when the main subject is not a person, the effect of exposure correction is relatively difficult, and noise is not noticeable due to exposure correction. Therefore, when the main subject is not a person, it is preferable to make the change range of the exposure correction relatively wide so that the difference in the large change range can be confirmed. Similarly, regarding the characteristics and contrast relating to the color tone, since the exposure correction has the same tendency as the gradation compression processing, it is preferable to change the change width of the gradation compression amount in accordance with these characteristics.

  Moreover, it is good also as a structure which the control part 17 determines automatically the direction and change amount which change an exposure correction amount each time.

  In the second embodiment, the example in which the exposure amount at the time of imaging is changed in conjunction with the gradation compression amount has been shown. However, instead of changing the exposure amount, the gradation conversion processing characteristics and sensitivity are changed. It is also good. If the tone conversion processing characteristics and sensitivity are changed without changing the exposure amount, there is an advantage that only one imaging operation is required during bracketing. In addition to the exposure amount, the gradation conversion processing characteristics and sensitivity may be changed.

  An electronic camera provided with both the gradation compression processing that is not linked with the gradation compression amount described in the first embodiment and the gradation compression processing that is linked with the gradation compression amount described in the second embodiment, This is effective as a specific embodiment of the present invention. In such an electronic camera, which gradation compression processing is to be performed can be designated by the user or automatically, and the selected gradation compression processing includes the bracketing function described in the above embodiments. good.

  In the above embodiments, the use of a plurality of images generated by bracketing has not been described in detail, but these images may be used in any manner. For example, the image may be displayed in parallel on the monitor 16 and the user may select any image. In this case, it is preferable to make it possible to reset the gradation compression processing as appropriate. Moreover, it is good also as a structure which links | relates and records all the produced | generated several images.

  Further, for example, a matrix display as shown in FIG. 12 may be performed. By performing such display, the user can easily recognize the difference in the gradation compression mode (gradation compression amount) and the exposure correction amount. When performing such a matrix display, it is preferable that the image can be appropriately enlarged in order to compare and confirm detailed details. For example, the main subject portion may be automatically enlarged and displayed, or a plurality of images may be enlarged and displayed in accordance with the user's enlargement designation.

  In each of the above-described embodiments, the example in which the magnitude of the gradation compression amount (brightness improvement amount) can be set in three levels (High / Normal / Low) has been described, but the present invention is not limited to this example. The number of stages other than three may be set, or a continuous gradation compression amount may be set using a slider bar or the like.

In each of the above embodiments, the gradation curve G of the gradation conversion process shown in FIG. 4 and the parameters fg (F _H , F _N , F _L ) of the gradation compression process shown in FIG. For example, it may be configured to change according to “portrait mode”, “landscape mode”, etc., may be configured to change according to the contrast level of the image, and may be changed according to the image adjustment mode. It is good also as a structure. Further, the gradation curve G and the parameter fg may be changed according to the image determination result by scene analysis or face recognition. As described above, by appropriately changing the gradation curve G and the parameter fg, it is possible to perform gradation conversion processing and dark portion gradation correction optimized for the image.

  In the above-described embodiment, the example in which the technique of the present invention is realized in the electronic camera 1 has been described. However, the present invention is not limited to this. For example, the present invention can be similarly applied to a compact type electronic camera, a movie camera for taking a moving image, and the like.

  Further, the same processing as the bracketing function by the electronic camera described in the above embodiments may be realized by software by a computer and an image processing program. In this case, what is necessary is just to make it the structure which implement | achieves part or all of the process after step S24 demonstrated with the flowchart of FIG. Or what is necessary is just to set it as the structure which implement | achieves a part or all of the process after step S57 demonstrated with the flowchart of FIG. 11 with a computer. In order to realize it with a computer, it is only necessary to change the gradation conversion processing characteristics and sensitivity instead of changing the exposure amount. In addition to the image data, the contents of the gradation compression process may be supplied to the computer. Such information can be supplied using the EXIF information of the image data. By adopting such a configuration, it is possible to perform the same processing as in the above embodiments.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. For this reason, the above-described embodiments are merely examples in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the scope of claims, and is not restricted by 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.

It is a figure which shows the structure of the electronic camera 1 of 1st Embodiment. It is a functional block diagram of electronic camera 1 of a 1st embodiment. It is a flowchart which shows the operation | movement at the time of imaging | photography of the electronic camera 1 of 1st Embodiment. It is a figure explaining a gradation curve. It is a figure explaining the parameter fg of gradation compression. It is a figure explaining a low pass filter. 4 is a flowchart illustrating an operation at the time of photographing of the electronic camera 1 when a bracketing function is set in the electronic camera 1 of the first embodiment. It is a figure which shows an example of a bracketing setting screen. It is another flowchart which shows the operation | movement at the time of imaging | photography of the electronic camera 1 of 2nd Embodiment. It is a figure which shows an example of the exposure conditions according to a gradation compression mode. It is a flowchart which shows the operation | movement at the time of imaging | photography of the electronic camera 1 when the bracketing function is set in the electronic camera 1 of 2nd Embodiment. It is a figure which shows an example of utilization of the several image produced | generated by bracketing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic camera, 2 ... Shooting lens, 14 ... Image sensor, 17 ... Control part

Claims (6)

An imaging unit that captures a subject image and generates an image;
A setting unit for setting a control value related to the brightness of the image;
A correction unit that performs correction to improve the brightness of the dark gradation of the image data of the image;
A control unit that associates and changes the control value and the correction condition by the correction unit, and generates a plurality of images including at least two images having different correction conditions ;
A reception unit that receives user designation regarding at least one of the control value and the correction condition;
The control unit generates the plurality of images by associating and changing the control value and the correction condition with a predetermined change width based on the content specified by the user.
Imaging device comprising a call. The imaging device according to claim 1 ,
The said control part determines the said change width based on the characteristic of the said image produced | generated by the said imaging part. The imaging device characterized by the above-mentioned. The imaging device according to claim 2 ,
The control unit determines the change width based on at least one of a type of a main subject of the image generated by the imaging unit, a characteristic related to a color tone, and a characteristic related to contrast. . The imaging device according to claim 1,
The setting unit includes, as the control value, at least one of an exposure amount at the time of imaging by the imaging unit, a gradation conversion characteristic when performing gradation conversion processing on the image generated by the imaging unit, and sensitivity. An image pickup apparatus characterized by setting. The imaging device according to claim 1,
The plurality of images include an image that has been corrected by the correction unit and an image that has not been corrected by the correction unit. The imaging device according to claim 1,
The plurality of images include a plurality of images having the same control value and different correction conditions.

Images