JP2009260567A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device which can correct distortion according to photographing conditions or use of images and makes images with less uncomfortable sense. <P>SOLUTION: A microcomputer 116 acquires photographing mode information at photographing (step S601), as well as a focal length of a lens 101 at photographing (step S602). Then, the microcomputer 116 acquires a target value of distortion quantity corresponding to the photographing mode and the focal length of the lens 101 at photographing (step S603). After acquisition of the target value of distortion quantity, it reads out a distortion correction parameter corresponding to the acquired target value of distortion quantity from a flash memory 118 (step S604). A distortion correction processing section 181 uses the distortion correction parameter to correct distortion according to the distortion correction parameter obtained in the step S604 (step S605). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus capable of performing distortion correction processing on image data acquired via an imaging element.

In recent years, digital cameras equipped with a distortion correction function have been developed. The distortion correction function is a function for correcting distortion in the peripheral portion of image data acquired in a distorted state due to distortion characteristics (hereinafter referred to as distortion) characteristics of the lens. As a proposal related to such distortion correction, Patent Document 1 has been proposed. In this Patent Document 1, the distortion is corrected according to the calibration parameter of the lens so that the distortion can be appropriately corrected even when a large distortion occurs in the peripheral portion of the image such as a wide-angle lens or a fisheye lens. I have to.
JP 2005-252754 A

  With the distortion correction function of the digital camera, it is possible to correct distortion of image data that is actually distorted according to the distortion characteristics of the lens. However, it may be better not to perform distortion correction depending on the shooting mode and the focal length of the lens. For example, some recent digital cameras have a function of creating a panoramic image by connecting a plurality of captured image data. In order to appropriately perform such panorama image creation processing, it is generally preferable that the images to be joined have no distortion. On the other hand, when shooting with a wide angle of view using a wide-angle lens, an image with the peripheral distortion left may appear more natural than an image without distortion. In such a case, it is better to perform correction that leaves distortion. In the method of Patent Document 1, since it is not possible to perform appropriate distortion correction according to shooting conditions and application of an image, an uncomfortable image may be recorded as a result of distortion correction.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus that can perform distortion correction according to shooting conditions and use of an image, and obtain an image with less sense of incongruity.

  In order to achieve the above object, an imaging apparatus according to a first aspect of the present invention determines an imaging unit that captures a subject and obtains image data, and a target value of a distortion amount when distortion correction is performed on the image data. A distortion amount target determination unit, a distortion correction parameter storage unit that stores distortion correction parameters used in the distortion correction in association with the distortion amount target value, and the distortion determined by the distortion amount target determination unit A distortion correction unit that reads out a distortion correction parameter corresponding to a target value of the amount from the distortion correction parameter storage unit and corrects the distortion of the image data using the read distortion correction parameter.

  According to the present invention, it is possible to perform distortion correction according to shooting conditions and use of an image, and to obtain an image with little uncomfortable feeling.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the present invention is not limited only to the components, types, combinations, shapes, relative arrangements, and the like described in the embodiments described below.

  FIG. 1 is a block diagram of a digital still camera as an example of an imaging apparatus according to an embodiment of the present invention. A digital still camera shown in FIG. 1 includes a lens 101, a lens driving mechanism 102, an image sensor 103, an analog processing unit 104, an analog / digital (A / D) conversion unit 105, a bus 106, an SDRAM 107, Image processing unit 108, AE processing unit 109, AF processing unit 110, JPEG processing unit 111, memory interface (I / F) 112, recording medium 113, LCD driver 114, LCD 115, and microcomputer 116 And an operation unit 117 and a flash memory 118.

  The lens 101 condenses the optical image of the subject on the image sensor 103. The lens 101 is a variable focus lens, and is moved in the optical axis direction by a lens driving mechanism 102 that is driven in accordance with an instruction from the microcomputer 116. Thereby, it is possible to change the focal length of the lens 101 and the focus state on the subject. In addition, a diaphragm mechanism and a mechanical shutter mechanism (not shown) are provided in the vicinity of the lens 101. By driving a diaphragm mechanism (not shown) in accordance with an instruction from the microcomputer 116, the amount of light of the subject can be adjusted. At the time of shooting, the exposure time of the image sensor 103 can be controlled by driving a mechanical shutter mechanism (not shown) in accordance with an instruction from the microcomputer 116.

The focal length that can be set has a range in the design of the lens 101, and an arbitrary focal length cannot be set within that range. In the case of the lens 101, when the shortest focal length is a and the longest focal length is b, for example, within the range from a to b
(Ba) / 10
It is assumed that the focal lengths of 11 states including a and b can be set at intervals of.

  The image sensor 103 is an image sensor in which a Bayer array color filter is arranged in front of a photodiode constituting a pixel. The Bayer array has a line in which R pixels and G (Gr) pixels are alternately arranged in a horizontal direction, and a line in which G (Gb) pixels and B pixels are alternately arranged, and the two lines are further divided. It is configured by alternately arranging in the vertical direction. The image sensor 103 receives the light collected by the lens 101 by a photodiode that constitutes a pixel and performs photoelectric conversion, thereby outputting the amount of light to the analog processing unit 104 as a charge amount. Note that the image sensor 103 may be a CMOS method or a CCD method.

  The analog processing unit 104 performs waveform shaping on the electrical signal (analog image signal) output from the image sensor 103 while reducing reset noise and the like, and further increases the gain so that the target brightness is obtained. The A / D conversion unit 105 converts the analog image signal output from the analog processing unit 104 into a digital image signal (hereinafter referred to as image data).

  A bus 106 is a transfer path for transferring various data generated in the digital camera to each unit in the digital camera. The bus 106 includes an A / D conversion unit 105, an SDRAM 107, an image processing unit 108, an AE processing unit 109, an AF processing unit 110, a JPEG processing unit 111, a memory I / F 112, an LCD driver 114, It is connected to the microcomputer 116.

  The image data obtained by the A / D conversion unit 105 is temporarily stored in the SDRAM 107 via the bus 106. The SDRAM 107 is a storage unit that temporarily stores various data such as image data obtained by the A / D conversion unit 105 and image data processed by the image processing unit 108 and the JPEG processing unit 111.

  The image processing unit 108 includes at least a distortion correction processing unit 181 and further includes a white balance correction unit, a color conversion processing unit, a color reproduction processing unit, a noise reduction processing unit, and the like (not shown). The image processing unit 108 performs image processing such as white balance correction processing, color conversion processing and color reproduction processing, noise reduction processing, and distortion correction processing on the image data read from the SDRAM 107. The distortion correction processing unit 181 performs distortion correction of the image data based on the distortion correction parameter stored in the flash memory 118.

  Here, the image data after the image processing is performed by the image processing unit 108 is synchronized from the image data based on the Bayer array to the image data composed of RGB information per pixel, and the synchronized image data is the SDRAM 107. Is remembered.

  The AE processing unit 109 calculates subject luminance using the image data. The data for calculating the subject brightness may be an output of a dedicated photometric sensor. The AF processing unit 110 extracts a high-frequency component signal from the image data, and acquires a focus evaluation value by AF (Auto Focus) integration processing.

  When recording image data, the JPEG processing unit 111 reads RGB image data from the SDRAM 107 and compresses the read image data according to the JPEG compression method. The compressed image data is temporarily stored in the SDRAM 107 and then recorded on the recording medium 113 via the memory I / F 112. Here, the recording medium 113 is, for example, a recording medium including a memory card that can be attached to and detached from the camera body, but is not limited thereto.

  The LCD driver 114 displays an image on the LCD 115. When JPEG compressed image data recorded on the recording medium 113 is reproduced, the JPEG processing unit 111 reads out the JPEG compressed image data recorded on the recording medium 113 and performs expansion processing, and then expands the image. Data is temporarily stored in the SDRAM 107. The LCD driver 114 reads the image data from the SDRAM 107, converts the read image data into a video signal, and then outputs the image data to the LCD 115 to display an image.

  The microcomputer 116 having functions as a distortion amount target determination unit and a focal length acquisition unit comprehensively controls various sequences of the digital camera body. An operation unit 117 and a flash memory 118 are connected to the microcomputer 116.

  The operation unit 117 is an operation member such as a power button, a release button, a zoom button, and various input keys. When one of the operation members of the operation unit 117 is operated by the user, the microcomputer 116 executes various sequences according to the user's operation. The power button is an operation member for instructing power on / off of the digital camera. When the power button is pressed, the microcomputer 116 turns the digital camera on or off. The release button has a two-stage switch including a 1st release switch and a 2nd release switch. When the release button is pressed halfway and the 1st release switch is turned on, the microcomputer 116 performs a shooting preparation sequence such as AE processing and AF processing. In addition, when the release button is fully pressed and the 2nd release switch is turned on, the microcomputer 116 executes the shooting sequence to perform shooting. The zoom button has a wide button and a tele button. When the wide button is pressed, the microcomputer 116 executes the lens driving sequence to drive the lens driving mechanism 102 and changes the focal length of the lens 101 to the short focal length side. When the tele button is pressed, the microcomputer 116 executes the lens driving sequence to drive the lens driving mechanism 102 and changes the focal length of the lens 101 to the long focal length side. Various input keys having a function as a shooting mode setting unit are used for various input operations such as setting of a shooting mode.

  A flash memory 118 having a function as a distortion correction parameter storage unit includes a distortion amount target value determination table for distortion correction, a distortion correction parameter corresponding to the distortion amount target value and focal length for distortion correction, and a digital value. Various parameters necessary for camera operation are stored. The flash memory 118 also stores a program executed by the microcomputer 116. The microcomputer 116 reads parameters necessary for various sequences from the flash memory 118 according to a program stored in the flash memory 118, and executes each process.

FIG. 2 is a flowchart showing processing at the time of shooting in the digital camera shown in FIG.
In FIG. 2, the microcomputer 116 determines whether or not the user has pressed the release button halfway to turn on the first release switch (step S201). In the determination in step S201, the microcomputer 116 repeatedly performs the determination in step S201 until the first release switch is turned on.

  On the other hand, if it is determined in step S201 that the first release switch is turned on, the microcomputer 116 executes AF processing (step S202). That is, the microcomputer 116 drives the lens driving mechanism 102 so that the image of the subject condensed on the image sensor 103 becomes the clearest from the AF evaluation value obtained by the AF processing unit 110 to focus the lens 101. adjust. Next, the microcomputer 116 causes the AE processing unit 109 to calculate subject brightness (step S203). After that, the microcomputer 116 calculates the aperture value and shutter speed at the time of shooting based on the subject brightness calculated in the AE processing unit 109, the aperture value stored in the flash memory 118 in advance, and the shutter speed determination table (step). S204).

  Next, the microcomputer 116 determines whether the release button is fully pressed by the user and the 2nd release switch is turned on (step S205). In step S205, the microcomputer 116 repeats the determination in step S205 until the 2nd release switch is turned on.

  On the other hand, when the 2nd release switch is turned on in the determination in step S205, the microcomputer 116 controls the aperture mechanism and the mechanical shutter mechanism (not shown) using the aperture value and the shutter speed calculated in step S204. Then, shooting is performed (step S206). Next, the microcomputer 116 causes the image processing unit 108 to perform image processing such as white balance correction processing, color correction processing, distortion correction processing, and synchronization processing on the image data obtained by photographing (step S207). . Next, the microcomputer 116 uses the JPEG processing unit 111 to JPEG-compress the image data after the image processing (step S208). Finally, the microcomputer 116 records the JPEG compressed image data obtained by JPEG compression on the recording medium 113 (step S209).

  As described above, in the process of FIG. 2, when the 1st release switch is turned on, calculation of conditions necessary for photographing such as calculation of exposure conditions is executed, and when the 2nd release switch is turned on, the subsequent processes are executed.

  Hereinafter, the distortion correction processing in the present embodiment will be described. In the present embodiment, a distortion amount target value at the time of distortion correction is determined according to the shooting mode and the focal length of the lens 101 at the time of shooting.

  When distortion correction processing is performed on the image data obtained when the focal length of the lens 101 is short and the shooting angle of view is wide so that distortion in the peripheral portion is eliminated, the image obtained after distortion correction is stretched from the center toward the outside. The image looks like this.

  FIG. 3A is a diagram illustrating an example of a case where distortion correction processing is performed so as to eliminate distortion with respect to image data having barrel distortion. When distortion correction processing is performed on image data having barrel distortion, as shown in FIG. 3A, the image obtained after correction is an image that is stretched from the center toward the four corners. It becomes. For this reason, when there is a circular image 201 like a face in the periphery of the image, the image 201 is stretched in an elliptical shape. Therefore, an image obtained as a result of distortion correction becomes an unnatural image. Although illustration is omitted, when image data having pincushion distortion (the peripheral portion of the image is distorted in a pincushion) is subjected to distortion correction processing that eliminates distortion, the image obtained after correction is The image is stretched in the vertical and horizontal directions from the center.

  In either case, when the focal length of the lens 101 is short, it is preferable to correct the distortion so that the peripheral distortion remains. Here, as a way of viewing a distorted image, a barrel-shaped distortion is more likely to be seen more naturally than a pincushion-type distortion. Therefore, when the focal length of the lens 101 is short, it is desirable to perform distortion correction so that barrel distortion remains as shown in FIG.

  On the other hand, when the focal length of the lens 101 is long and the shooting angle of view is narrow, the light from the subject is substantially parallel to the shooting direction. For this reason, even if distortion correction processing is performed so that distortion is eliminated, an unnatural image is less likely to occur than when the focal length of the lens 101 is short. In such a case, a more natural image can be obtained by performing distortion correction processing that eliminates distortion.

Even if the focal length of the lens 101 is short, it may be better to perform distortion correction processing that eliminates distortion depending on the shooting mode.
For example, in the case of a panorama synthesis mode in which a plurality of images are joined to generate a single panoramic image, if the joining process is performed with distortion left in each image, FIG. There is a high possibility that an unnatural image as shown in (a) where the joints between the images do not match is generated. Therefore, in the case of the panorama synthesis mode, it is desirable to perform the joining process after correcting so that distortion in each image is eliminated regardless of the focal length of the lens 101. It is possible to generate a natural panoramic image as shown in FIG. 4B by performing the stitching process after eliminating distortion in each image.

  Further, since the peripheral portion is reduced in barrel distortion, and the peripheral portion is enlarged in pincushion distortion, if distortion is left in the image in the document photographing mode for photographing a document, FIG. As shown in FIG. 4, the characters are not arranged in a straight line, which makes it difficult to read. Therefore, even in the document shooting mode, it is desirable to correct so that distortion is eliminated regardless of the focal length of the lens 101. By performing correction to eliminate distortion, it is possible to arrange characters in a straight line as shown in FIG. As described above, if the correction is made so that the distortion is eliminated, the image in which the peripheral part is stretched is obtained. However, in the case of a document, the peripheral part is often a margin or the like. There is no particular problem.

  In consideration of the above, in the present embodiment, distortion correction is performed by setting a distortion amount target value in the distortion correction processing according to the shooting mode and the focal length.

  FIG. 6 is a diagram illustrating an example of a table (distortion amount target value calculation table) for determining a distortion amount target value from the photographing mode and the focal length of the lens 101. This distortion amount target value calculation table is stored in the flash memory 118.

  Here, in the distortion amount target value calculation table shown in FIG. 6, the normal shooting mode, the panorama synthesis mode, the document shooting mode, and other modes are shown as shooting modes. In addition, the focal length is an example in which the shortest focal length is 28 mm, the longest focal length is 110 mm, the interval is 8 mm, and 11 states. Further, the distortion amount target value indicates a TV distortion value that is generally known as a technique for representing the distortion amount.

FIG. 7 is a diagram showing TV distortion. TV distortion indicates the amount of distortion of an image when displayed on a television (TV) monitor. This TV distortion shows the distortion in the long side direction of the image as a percentage, ie,
(Distortion amount Δh) / (width h in the long side direction of the image) × 100%
Given by. Note that the sign of the strain amount Δh is positive in the case of a pincushion-type strain (broken line in the figure) and negative in the case of a barrel-type strain (solid line in the figure). As can be seen from the relationship in FIG. 7, the TV distortion indicates that the smaller the absolute value of the numerical value, the smaller the distortion.

  The normal shooting mode shown in FIG. 6 is a shooting mode in which shooting is performed simply according to the processing shown in FIG. In this case, the distortion amount target value is determined according to the focal length. In FIG. 6, 28 mm to 52 mm is a short focal length range, 60 mm to 84 mm is a medium focal length range, and 92 mm to 110 mm is a long focal length range, and a distortion amount target value is assigned to each range. In the case of the short focal length range, the distortion amount target value is set to −1.0% in order to perform distortion correction so that barrel distortion remains. In the case of the long focal length range, the distortion amount target value is set to 0% in order to perform distortion correction so that no distortion remains. In the case of the intermediate focal length range, distortion correction is performed so that a barrel distortion that is intermediate between the case of the short focal length range and the case of the long focal length range remains. In the example of FIG. 6, the distortion amount target value is set to −0.3%.

  The panorama synthesis mode is a shooting mode in which a plurality of images obtained by changing the shooting direction are connected to generate one panoramic image. In the panorama composition mode, the distortion amount target value is set to 0% regardless of the focal length in order to perform distortion correction so that no distortion remains.

  The document shooting mode is a shooting mode suitable for shooting a document. In the document photographing mode, the distortion amount target value is set to 0% regardless of the focal length in order to perform distortion correction so that no distortion remains.

  The other modes are shooting modes that are not included in the above three shooting modes (for example, continuous shooting mode, bracket shooting mode, etc.). Also in this case, the distortion amount target value is determined according to the focal length as in the normal shooting mode. Note that the relationship between the focal length and the target distortion amount is the same as in the normal shooting mode.

  FIG. 8 shows distortion correction parameters for each focal length corresponding to the distortion amount target value. This distortion correction parameter is also stored in the flash memory 118. As shown in FIG. 8, a distortion correction parameter Pm_n is assigned to the distortion amount target value and the focal length. Note that m corresponds to a distortion amount target value. The distortion correction parameter corresponding to the distortion amount target value of 0% is m = 00. The distortion correction parameter corresponding to the distortion amount target value of −0.3% is m = 03. The distortion correction parameter corresponding to the distortion amount target value of −1.0% has m = 10. N corresponds to the focal length. The distortion correction parameter corresponding to the focal length of the lens 101 of 28 mm is n = 1. The distortion correction parameter corresponding to the focal length of the lens 101 of 36 mm is n = 2. Thereafter, similarly, every time the focal length increases by 8 mm (only the longest focal length is 10 mm), n increases by one. For example, when the distortion target value is −1.0% and the focal length is 28 mm, P10_1 is used as the distortion correction parameter.

  Here, the distortion correction parameters will be described with reference to FIG. The distortion correction parameter is a parameter for correcting the distortion determined for each focal length into a distortion corresponding to the distortion amount target value. As a method for obtaining the distortion correction parameter, for example, photographing is executed while changing the focal length of the lens 101 at the time of manufacturing a digital camera or the like, and an image distortion amount (TV distortion) is obtained for each focal length. A parameter for setting the obtained image distortion amount to a distortion amount corresponding to each distortion amount target value is the distortion correction parameter shown in FIG.

  FIG. 9 shows distortions corresponding to the target distortion amounts of 0%, −0.3%, and −1.0%, and distortions corresponding to the focal lengths of 110 mm, 60 mm, and 28 mm. For example, the distortion correction parameter P00_1 shown in FIG. 8 is a parameter for correcting the distortion corresponding to 28 mm shown in FIG. 9 into the distortion corresponding to the target amount of distortion 0%. Similarly, the distortion correction parameter P03_5 illustrated in FIG. 8 is a parameter for correcting the distortion corresponding to 60 mm illustrated in FIG. 9 to the distortion corresponding to the target distortion amount value −0.3%.

  Here, different distortion correction parameters are used depending on the distortion correction method. Here, description of how to obtain the distortion correction parameter corresponding to each method is omitted, but the method of the present embodiment can be applied regardless of which method is used.

  FIG. 10 is a flowchart showing the distortion correction processing in the present embodiment. The process illustrated in FIG. 10 is a process performed by the distortion correction processing unit 181 during the image processing performed in step S207 of FIG.

  First, the microcomputer 116 acquires shooting mode information at the time of shooting (step S601). The shooting mode information can be changed by the user operating the input key of the operation unit 117. By temporarily storing the shooting mode information immediately before shooting changed by the operation of the input key immediately before shooting in the SDRAM 107, the microcomputer 116 can acquire shooting mode information at the time of shooting after shooting. .

  Next, the microcomputer 116 acquires the focal length of the lens 101 at the time of shooting (step S602). The focal length of the lens 101 can be changed by the user operating the zoom button of the operation unit 117. By temporarily storing the last focal length changed by the operation of the zoom button immediately before shooting in the SDRAM 107, the microcomputer 116 can acquire the focal length at the time of shooting after shooting.

  Next, the microcomputer 116 acquires a distortion amount target value corresponding to the shooting mode at the time of shooting and the focal length of the lens 101 (step S603). That is, the microcomputer 116 obtains the distortion amount target value corresponding to the shooting mode information acquired in step S601 and the focal length of the lens 101 acquired in step S602 from the distortion amount target value calculation table stored in the flash memory 118. obtain.

  After acquiring the distortion amount target value, the microcomputer 116 acquires a distortion correction parameter corresponding to the acquired distortion amount target value (step S604). That is, the microcomputer 116 reads out from the distortion correction parameter stored in the flash memory 118 the distortion correction target value acquired in step S603 and the distortion correction parameter corresponding to the focal length of the lens 101 acquired in step S602.

  After acquiring the distortion correction parameters, the microcomputer 116 transfers the acquired distortion correction parameters to the distortion correction processing unit 181 via the bus 106. In response, the distortion correction processing unit 181 performs distortion correction processing according to the distortion correction parameter acquired in step S604 (step S605).

  As described above, according to the present embodiment, the distortion amount target value for the distortion correction processing is determined according to the shooting mode at the time of shooting and the focal length of the lens 101, and the determined distortion amount target value is determined. By performing distortion correction processing according to the distortion correction parameters corresponding to the above, appropriate distortion correction processing according to the shooting mode and the focal length of the lens 101 can be performed.

  Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention.

  For example, in the above-described embodiment, the distortion amount target value is set for each of the three types of focal length ranges. However, the focal length range is not limited to three types. There may be at least two types of short focal length and long focal length, and there may be four or more types. When there are four or more types of focal length ranges, the target amount of distortion is set according to the focal length range.

  Further, in the above-described embodiment, only four types of shooting modes are illustrated, but this is not limited to four types. Furthermore, in the above-described embodiment, the distortion amount target value is represented as TV distortion, but may be represented using a distortion amount other than TV distortion.

  In the above-described embodiment, the distortion amount target value is determined using both the photographing mode and the focal length. However, the distortion amount target value may be determined from only one of them.

  Furthermore, the above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some configuration requirements are deleted from all the configuration requirements shown in the embodiment, the above-described problem can be solved, and this configuration requirement is deleted when the above-described effects can be obtained. The configuration can also be extracted as an invention.

1 is a block diagram of a digital still camera as an example of an imaging apparatus according to an embodiment of the present invention. It is a flowchart which shows the process at the time of imaging | photography in the digital camera shown in FIG. FIG. 3A is a diagram showing an example of a case where distortion correction processing is performed so as to eliminate distortion for image data having barrel-shaped distortion in the case of a short focal length, and FIG. It is a figure which shows the example at the time of performing the distortion correction process in one Embodiment of this invention in the case of a focal distance. FIG. 4A is a diagram illustrating an example of a case where a distortion correction process for leaving distortion is performed in the panorama synthesis mode, and FIG. 4B is a diagram illustrating the distortion correction process according to the embodiment of the present invention in the panorama synthesis mode. FIG. FIG. 5A is a diagram illustrating an example of a case where distortion correction processing that leaves distortion is performed in the document shooting mode, and FIG. 5B is a diagram illustrating distortion correction processing according to an embodiment of the present invention performed in the document shooting mode. FIG. It is a figure which shows the example of a distortion amount target value calculation table. It is a figure for demonstrating TV distortion. It is a figure which shows the distortion correction parameter for every focal distance corresponding to a distortion amount target value. It is a figure for demonstrating a distortion correction parameter. It is a flowchart shown about the distortion correction process in one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Lens, 102 ... Lens drive mechanism, 103 ... Image sensor, 104 ... Analog processing part, 105 ... Analog / digital (A / D) conversion part, 106 ... Bus, 107 ... SDRAM, 108 ... Image processing part, 109 ... AE processing unit, 110 ... AF processing unit, 111 ... JPEG processing unit, 112 ... memory interface (I / F), 113 ... recording medium, 114 ... LCD driver, 115 ... LCD, 116 ... microcomputer, 117 ... operation unit, 118: Flash memory, 181: Distortion correction processing unit

Claims (7)

An imaging unit that captures image data by photographing a subject;
A distortion amount target determining unit for determining a target value of the distortion amount when correcting the distortion of the image data;
A distortion correction parameter storage unit that stores a distortion correction parameter used in the distortion correction in association with the target value of the distortion amount;
A distortion correction parameter is read out from the distortion correction parameter storage unit according to the distortion amount target value determined by the distortion amount target determination unit, and distortion correction of the image data is performed using the read distortion correction parameter. And
An imaging apparatus comprising: A shooting mode setting unit for setting shooting mode information indicating the shooting mode;
The imaging apparatus according to claim 1, wherein the distortion amount target determination unit determines a target value of the distortion amount based on shooting mode information set by the shooting mode setting unit. A lens for condensing the image of the subject on the imaging unit;
A focal length acquisition unit for acquiring focal length information of the lens at the time of shooting;
Further comprising
The distortion amount target determination unit further determines a target value of the distortion amount based on focal length information of the lens at the time of photographing acquired by the focal length acquisition unit. Imaging device.   When the distortion amount target determination unit indicates that the shooting mode information set by the shooting mode setting unit is a shooting mode for acquiring a plurality of image data on the assumption that they are connected to each other, the image The imaging apparatus according to claim 2 or 3, wherein a target value of the distortion amount is determined so that distortion in data is eliminated.   The imaging apparatus according to claim 4, wherein the shooting mode for acquiring a plurality of image data on the assumption that the images are connected to each other includes a panorama synthesis mode.   The distortion amount target determination unit, when the shooting mode information set by the shooting mode setting unit indicates a shooting mode for shooting a document, the distortion amount so as to eliminate distortion in the image data. The image pickup apparatus according to claim 2, wherein a target value is determined.   The distortion amount target determination unit, when the focal length information of the lens at the time of shooting acquired by the focal length acquisition unit indicates that it is longer than a predetermined distance, the distortion amount so as to eliminate distortion in the image data When the focal length information of the lens at the time of shooting acquired by the focal length acquisition unit indicates that the target value is shorter than the predetermined distance, a distortion of a mold corresponding to the image data remains. The imaging apparatus according to claim 3, wherein a target value of the distortion amount is determined.

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