JP2008092440A - Camera, and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To photograph an optimal image even in a case where an interchangeable lens corresponding to APS-C size is used for a camera including an imaging element larger than APS-C size. <P>SOLUTION: The camera comprises: an imaging element 107 which picks up a subject image and outputs an image signal; an information acquiring means 117 which acquires interchangeable lens information indicating characteristics of an interchangeable lens 200 mounted in the camera and converter lens information indicating characteristics of a converter lens mounted in the camera; and a correction data generating means 117 which generates correction data for correcting image deterioration, in a surrounding part of a photographed picture, caused by a photographing optical system including the interchangeable lens 200 and the converter lens 300. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera and an image processing program for optimizing an image when a converter lens is inserted and photographed.

An interchangeable lens for a camera having an APS-C size image sensor is known (for example, Patent Document 1).
JP-A-2005-99066

  However, when an interchangeable lens corresponding to the APS-C size is used for a camera having an image sensor larger than the APS-C size, there is a problem that an optimal image cannot be taken.

(1) A camera according to a first aspect of the present invention is an image sensor that captures a subject image and outputs an image signal, interchangeable lens information indicating the characteristics of the interchangeable lens mounted on the camera, and a converter lens mounted on the camera. Information acquisition means for acquiring converter lens information indicating the characteristics of the image sensor, and the surroundings in the shooting screen caused by the shooting optical system including the interchangeable lens and the converter lens based on the acquired interchangeable lens information and the converter lens information Correction data generation means for generating correction data for correcting image degradation of the image forming section.

(2) In the camera according to claim 2, in the camera according to claim 1, the interchangeable lens information is interchangeable lens model name information indicating a model name of the interchangeable lens, and the converter information is converter model name information indicating a converter model name. The correction data generation means includes correction data storage means for storing correction data corresponding to the interchangeable lens model name information and converter model name information, and the interchangeable lens model name information and converter model name information acquired by the information acquisition means. And a search means for searching for correction data from the correction data storage means.

(3) According to the invention of claim 3, in the camera according to claim 1, the interchangeable lens information is interchangeable lens type name information indicating a model name of the interchangeable lens, and the converter information is converter model name information indicating a converter model name. The correction data generation means includes characteristic data storage means for storing optical characteristic data corresponding to the interchangeable lens model name information and the converter model name information, and the interchangeable lens model name information and the converter model name acquired by the information acquisition means. It includes a search means for searching for optical characteristic data from the characteristic data storage means based on the information, and a correction data calculation means for calculating correction data based on the searched characteristic data.

(4) According to the invention of claim 4, in the camera of claim 1, the interchangeable lens information is interchangeable lens characteristic data indicating the optical characteristics of the interchangeable lens, and the converter information is converter lens characteristic data indicating the optical characteristics of the converter lens. The correction data generation means generates correction data based on the interchangeable lens characteristic data and the converter lens characteristic data.

(5) The invention of claim 5 is the camera according to any one of claims 1 to 4, wherein the correction data is used to correct image data generated from an image signal output from the image sensor. The image processing device further includes image correction means for correcting image deterioration.
(6) According to the invention of claim 6, in the camera according to any one of claims 1 to 4, an image file in which correction data is added to image data generated by an image signal output from an image sensor is generated. And a file generation means.

(7) According to the invention of claim 7, in the camera according to any one of claims 1 to 4, the correction data is data for correcting the MTF characteristic of the photographing optical system including the interchangeable lens and the converter lens. It is characterized by including.
(8) The invention according to claim 8 is the camera according to any one of claims 1 to 4, wherein the correction data is used to correct a peripheral light amount drop of the photographing optical system including the interchangeable lens and the converter lens. It is characterized by including data.

(9) An image processing program according to a ninth aspect of the invention includes an image pickup device that picks up a subject and outputs an image signal, interchangeable lens information indicating characteristics of the interchangeable lens attached to the camera, and a converter attached to the camera. Information acquisition means for acquiring converter lens information indicating the characteristics of the lens, and based on the acquired interchangeable lens information and the converter lens information, in the photographing screen generated due to the photographing optical system including the interchangeable lens and the converter lens Read processing for reading image data and correction data acquired by a camera including correction data generation means for generating correction data for correcting image deterioration in the peripheral area, and image deterioration of image data read using the correction data A correction process for correcting the image is executed by a computer.
(10) An image processing program according to a tenth aspect of the present invention is a first reading process for reading image data acquired by a camera, interchangeable lens information indicating characteristics of an interchangeable lens mounted on the camera, and mounted on the camera. Based on the second reading process for reading converter lens information indicating the characteristics of the converter lens, the read interchangeable lens information and the converter lens information, and in the photographing screen generated due to the photographing optical system including the interchangeable lens and the converter lens. A computer executes correction data generation processing for generating correction data for correcting image degradation in the peripheral portion and correction processing for correcting the image degradation of image data read using the correction data.

(11) The invention of claim 11 is the image processing program according to claim 10, wherein the interchangeable lens information is interchangeable lens model name information indicating the model name of the interchangeable lens, and the converter information is a converter model name indicating the model name of the converter. The correction data generation process is information stored in a storage unit that stores correction data corresponding to the interchangeable lens model name information and the converter model name information based on the read interchangeable lens model name information and the converter model name information. And a search process for searching for the corrected data.
(12) The invention of claim 12 is the image processing program according to claim 10, wherein the interchangeable lens information is interchangeable lens model name information indicating the model name of the interchangeable lens, and the converter information is a converter model name indicating the converter model name. In the correction data generation process, the interchangeable lens type read in the second reading process with reference to the characteristic data storage means for storing the optical characteristic data corresponding to the interchangeable lens type name information and the converter type name information It includes a search process for searching for optical characteristic data based on name information and converter type name information, and a correction data calculation process for calculating correction data based on the searched optical characteristic data.

(13) The invention of claim 13 is the image processing program according to claim 10, wherein the interchangeable lens information is interchangeable lens characteristic data indicating the optical characteristics of the interchangeable lens, and the converter information is converter lens characteristics indicating the optical characteristics of the converter lens. In the correction data generation process, correction data is generated based on the interchangeable lens characteristic data and the converter lens characteristic data.
(14) The invention according to claim 14 is the image processing program according to claim 10, wherein the second reading process is performed in a shooting screen generated due to a shooting optical system including an interchangeable lens and a converter lens generated by the camera. The image processing apparatus further includes a selection process of reading correction data for correcting image degradation in the peripheral portion and selecting any one of the read correction data and the correction data calculated in the correction data generation process.

(15) The invention of claim 15 is the image processing program according to claim 9 or 10, wherein the correction data includes data for correcting the MTF characteristic of the photographing optical system including the interchangeable lens and the converter lens. It is characterized by.
(16) The invention of claim 16 is the image processing program according to claim 9 or 10, wherein the correction data includes data for correcting a peripheral light amount drop of the photographing optical system including the interchangeable lens and the converter lens. It is characterized by that.

According to the camera of the present invention, an image generated due to the imaging optical system including the interchangeable lens and the teleconverter based on the interchangeable lens information indicating the characteristics of the interchangeable lens and the converter lens information indicating the characteristics of the converter lens. Correction data for correcting deterioration can be generated.
According to the image processing program of the present invention, based on the interchangeable lens information indicating the characteristics of the interchangeable lens and the converter lens information indicating the characteristics of the converter lens, the image processing program is generated due to the photographing optical system including the interchangeable lens and the teleconverter. The image deterioration can be corrected using correction data for correcting the image deterioration.

-First embodiment-
A first embodiment of a camera according to the present invention will be described with reference to the drawings. FIG. 1 is a main part configuration diagram of an electronic camera 100 including an image sensor 101 and an interchangeable lens 200 and a teleconverter 300 that are attached to and detached from the electronic camera 100. FIG. 2 is a block diagram of a control system for the electronic camera 100, the interchangeable lens 200, and the teleconverter 300.

  The teleconverter 300 includes a lens 310 for enlarging subject light that has passed through the lens 210 of the interchangeable lens 200. This magnification is 1.5 times, for example.

  As shown in FIGS. 1 and 2, the interchangeable lens 200 includes a lens 210, a ROM-L 220, a CPU-L 221, an interface-L 222, and an encoder 223. The lens 210 is an optical system that forms an image of subject light on the light receiving surface of the image sensor 107. The imaging range of the lens 210 corresponds to an APS-C size imaging device, that is, 23.7 mm × 15.6 mm. The ROM-L 220 stores interchangeable lens information indicating features of the interchangeable lens 200 such as a model name of the interchangeable lens 200 and lens characteristic information. The lens characteristic information is data representing the MTF characteristic of the lens 210 and focal length data necessary for obtaining a peripheral light amount drop of a captured image generated by the lens 210. Hereinafter, the interchangeable lens 200 will be described as a single focus lens, but the present invention can also be applied to a variable focus lens.

  The MTF (Modulation Transfer Function) characteristic is an index for evaluating the imaging performance of the lens 210, and expresses how faithfully the contrast of the subject can be reproduced as a spatial frequency characteristic. In general, as shown in the MTF performance curve diagram of FIG. 3, the MTF characteristic of an interchangeable lens is such that the contrast value decreases as the image height increases, that is, the distance from the center of the photographing screen increases. As a result, the contrast deteriorates toward the periphery of the captured image. The MTF characteristics vary depending on the focal length, aperture value, and subject distance. Accordingly, MTF characteristic data associated with the focal length, the aperture value, and the subject distance is stored in the ROM-L 220 in a table format for each predetermined image height. In many cases, the user uses the teleconverter 300 to photograph a distant subject. Therefore, the subject distance can be omitted as a parameter of the ROM-L220.

  The decrease in the amount of peripheral light is a phenomenon in which the peripheral part in the shooting screen appears darker than the central part, and the four corners become dark when viewed in the captured image. The characteristics of the peripheral light amount drop vary depending on the angle of view (image height), the aperture value, and the microlens of the image sensor 107. Therefore, in order to obtain the angle of view of the optical system in which the teleconverter 300 and the interchangeable lens 200 are combined, focal length data is stored in the ROM-L 220 in a table format.

  The encoder 223 outputs a signal indicating the extension amount of the lens 210. The extension amount of the lens 210 corresponds to the subject distance. Therefore, the CPU-L 221 can determine the subject distance based on the output signal of the encoder 223.

  The CPU-L 221 controls each unit described above of the interchangeable lens 200. The CPU-L 221 communicates various information with the CPU-T 322 in the teleconverter 300 and the CPU-C 117 in the electronic camera 100 via the interface-L 222. For example, the CPU-L 221 transmits the interchangeable lens information and subject distance information read from the ROM-L 220 to the electronic camera 100.

  The teleconverter 300 includes a lens 310, an interface-TC 320, a ROM-T321, a CPU-T322, and an interface-TL323, as shown in FIGS. The ROM-T 321 stores tele-converter information such as the model name of the tele-converter 300 and the characteristic information of the lens 310. The characteristic information is data representing MTF characteristics of the lens 310 and data representing optical characteristics such as the magnification of the lens 310.

  Similar to the MTF characteristic data of the lens 210 in the interchangeable lens 200, the MTF characteristic data of the lens 310 is stored in the ROM-T 321 in a table format associated with each predetermined image height. The peripheral light amount drop characteristic data is the magnification of the lens 310, and these characteristic coefficients are stored in the ROM-T321.

  The CPU-T 322 communicates various information with the CPU-C 117 in the electronic camera 100 via the interface-TC 320. For example, the CPU-T 322 transmits the teleconverter information read from the ROM-T 321 to the electronic camera 100. Further, the CPU-T 322 transmits a command received from the electronic camera 100 via the interface-TC 320 to the interchangeable lens 200 via the interface-TL 323.

  As shown in FIGS. 1 and 2, the electronic camera 100 includes a quick return mirror 101, a focusing screen 102, a pentaprism 103, a photometric sensor 104, an eyepiece lens 105, a shutter 106, an image sensor 107, an image sensor 112, and focus detection. Sensor 108, interface-C110, AFE (Analog Front End) circuit 111, timing generator 113, image processing engine 114, compression circuit 115, RAM 116, CPU-C117, ROM-C118, LCD drive circuit 119, LCD120, operation unit 121, A card interface 122 and a memory card 123 are included.

  The shooting mode includes an optical viewfinder mode and a live view mode. The optical viewfinder is a mode in which a subject is confirmed with the optical viewfinder. The live view mode is a mode in which an image of a subject taken by the image sensor 112 is displayed on the LCD 120 as a moving image, and the subject is confirmed with an electronic viewfinder.

First, the case of the optical finder mode will be described.
Subject light that has entered the electronic camera 100 after passing through the interchangeable lens 200 and the teleconverter 300 is guided upward by the quick return mirror 101 positioned as shown by the solid line in FIG. Image. The subject light further enters the pentaprism 103. The pentaprism 103 guides the incident subject light to the eyepiece lens 105, while the subject light enters the photometric sensor 104 and forms a subject image on its imaging surface. The photometric sensor 104 is disposed at a position optically equivalent to the imaging element 107 with respect to the interchangeable lens 200. The photometric sensor 104 includes a CCD image sensor provided with a plurality of photoelectric conversion elements corresponding to pixels. The photometric sensor 104 images a subject image formed on the imaging surface, and outputs a photoelectric conversion signal corresponding to the brightness of the subject image to the CPU-C 117 as a photometric signal.

Next, the live view mode will be described.
The user can set the live view mode by operating the operation unit 121. When the live view mode is set, the CPU-C 117 switches the optical path by an optical system switching mechanism (not shown) so that the subject light is guided to the image sensor 112. Then, the image captured by the image sensor 112 is displayed on the LCD 120 as a moving image. Therefore, the user can determine the composition of shooting while looking at the image displayed on the LCD 120.
The following description is common to the optical finder mode and the live view mode unless otherwise specified.

  Part of the subject light passes through the semi-transmissive region of the quick return mirror 101, is reflected downward by the sub mirror 1101a, and enters the focus detection sensor 108. For example, the focus detection sensor 108 divides a focus detection light beam into a pair of focus detection light images and forms a focus detection optical system and a pair of split light images, and a focus detection signal corresponding thereto. A pair of CCD line sensors. The focus detection signal output from the CCD line sensor is input to the CPU-C 117.

  After the release, the quick return mirror 101 is rotated to a position indicated by a broken line in FIG. 1, and subject light is guided to the image sensor 107 through the shutter 106, and a subject image is formed on the imaging surface. The image sensor 107 is a photoelectric conversion element such as a CCD or a CMOS that converts received light of an object into an image signal corresponding to its intensity. The size of the image sensor 107 is 36 mm × 24 mm. Pixels are arranged in a matrix on the image sensor 107. One of R (red), G (green), and B (blue) filters is attached to the light receiving surface of each pixel of the light receiving element of the image sensor 107 in a Bayer array. Microlenses are provided on the front surface (subject side) of each filter in order to increase the light receiving sensitivity.

  The AFE circuit 111 is a circuit that performs analog processing on the image signal output from the image sensor 107 and then converts it to digital image data. Analog processing includes amplifier gain control and correlated double sampling. The gain of the amplifier is determined based on the ISO sensitivity set by the CPU-C 117. The timing generator 113 is a circuit that outputs a timing signal to the image sensor 107 and the AFE circuit 111 in accordance with an instruction from the CPU-C 117 and controls the drive timing of the image sensor 107 and the AFE circuit 111.

  The CPU-C 117 is an arithmetic circuit that controls each component of the electronic camera 100 and executes various data processing. In addition to controlling the timing generator 113, the CPU-C 117 controls an image processing engine 114, a compression circuit 115, a card interface 122, and an LCD drive circuit 119, which will be described later. Further, the CPU-C 117 calculates the shutter speed and the aperture value of the interchangeable lens 200 based on the brightness of the subject and the imaging sensitivity (ISO sensitivity) calculated based on the photometric signal output from the photometric sensor 104 described above. . Further, the CPU-C 117 calculates a focus adjustment state such as a defocus amount based on the focus detection signal output from the focus detection sensor 108 described above.

  The image processing engine 114 is configured by an ASIC or the like. The image processing engine 114 performs image processing such as white balance processing, gamma correction processing, color interpolation processing, contour enhancement, and vignette correction on the image data. The compression circuit 115 is a circuit that executes JPEG compression processing on the main image data that has been subjected to image processing by the image processing engine 114. The CPU-C 117 generates an image file from the main image data subjected to JPEG compression processing.

  The memory card interface 122 is an interface to which the memory card 123 can be attached and detached. The memory card interface 122 is an interface circuit that writes an image file to the memory card 123 and reads an image file recorded on the memory card 123 based on the control of the CPU-C 117. The memory card 123 is a semiconductor memory card such as a compact flash (registered trademark) or an SD card.

  The LCD drive circuit 119 is a circuit that drives the LCD 120 based on a command from the CPU-C 117. The LCD 120 is a liquid crystal display panel having an aspect ratio of 3: 3 and 4: The LCD 120 is used as a liquid crystal viewfinder and displays display data created by the CPU-C 117 based on the image file recorded on the memory card 123. The LCD 120 displays various information related to the image file (shutter speed, aperture value, ISO sensitivity, file name, etc.). The LCD 120 displays various setting menu screens of the electronic camera 100 based on an operation of an operation unit 121 described later. The contents of the setting menu include setting of a shooting mode and setting of whether the shot image data is recorded after being compressed or recorded as RAW data.

  The RAM 116 is used to temporarily store data during or after image processing, image compression processing, and display data creation processing. It is also used to temporarily store image data of a plurality of frames taken continuously during continuous shooting and moving image shooting. The ROM-C 118 is a memory that stores program data executed by the CPU-C 117.

  The operation unit 121 is a switch that receives a user operation. The operation unit 121 includes a power switch, a release switch, a setting menu display changeover switch, a setting menu determination button, and the like.

  Next, the operation of the electronic camera 200 will be described. When the power is turned on by the user operating the operation unit 121, the CPU-C 117 outputs a request signal for requesting the interchangeable lens 200 to transmit interchangeable lens information via the interface-C110. When the request signal from the electronic camera 100 is input via the interface-TC 320, the CPU-T 322 of the teleconverter 300 outputs the input request signal to the interchangeable lens 200 via the interface-TL 323. CPU-L221 of interchangeable lens 200 will read the interchangeable lens information memorize | stored in ROM-L220, if a request signal is input from the teleconverter 300 via interface-L222. The CPU-L 221 transmits the read interchangeable lens information via the interface-L 222.

  When the CPU-T322 receives the interchangeable lens information transmitted from the interchangeable lens 200 via the interface-TL323, the CPU-T322 reads the teleconverter information stored in the ROM-T321. Then, the CPU-T 322 transmits the interchangeable lens information received from the interchangeable lens 200 and the teleconverter information read from the ROM-T 323 to the electronic camera 100 via the interface-TC 320.

  The CPU-C 117 of the electronic camera 100 determines that the tele-converter 300 is attached when the information received via the interface-C 110 includes tele-converter information. If it is determined that the teleconverter 300 is attached, the CPU-C 117 calculates a correction value for correcting image degradation of the captured image based on the received interchangeable lens information and teleconverter information. In this embodiment, the interchangeable lens information is MTF characteristic data and focal length data, and the teleconverter information is MTF characteristic data and magnification data. The correction values are a pair of correction values including correction data for correcting image degradation due to MTF and correction data for correcting a peripheral light amount drop.

  The MTF characteristic of the photographing optical system composed of the interchangeable lens 200 and the teleconverter 300 is determined by the CPU-C 117 by the CPU-C 117 by the interchangeable lens 200 indicated by the solid line in FIG. The characteristic can be obtained by convolution integration. For simplicity, the CPU-C 117 may obtain the MTF characteristic constituted by the interchangeable lens 200 and the teleconverter 300 by multiplying the MTF characteristic of the interchangeable lens 200 and the MTF characteristic of the teleconverter 300. An alternate long and short dash line in FIG. 4 represents the MTF characteristic of the photographing optical system including the interchangeable lens 200 and the teleconverter 300. As shown by the one-dot chain line in FIG. 4, the captured image having the degraded MTF characteristic can be corrected by applying an edge enhancement process by the image processing engine 114. Therefore, the CPU-C 117 calculates an MTF correction value such that the MTF characteristic of the image after the contour enhancement process approximates at least the MTF characteristic of the interchangeable lens 210 indicated by the solid line in FIG. Then, the CPU-C 117 sets an MTF correction value in the image processing engine 114.

  The cause of the peripheral light amount drop will be described with reference to FIG. FIG. 9 is a schematic diagram illustrating a state in which a light beam passing through the lens 210 reaches the image sensor 107. Here, the teleconverter lens 300 is not attached.

The first main factor that causes the peripheral light amount drop is the phenomenon of the peripheral light amount due to the maximum angle of view 2θ. The maximum angle of view 2θ represents the range of the object space that can be captured in a certain screen as an angle. The half angle of view θ is an angle formed by the principal ray (light ray passing through the center of the stop) that is emitted from the object and corresponds to the maximum image height y _max on the imaging surface. The maximum angle of view is twice θ, that is, 2θ. The maximum image height y _max is 21.6 mm when the image sensor 107 is a full-size element of 24 mm × 36 mm.

Generally, a light beam emitted from the center of the subject and directed toward the center of the imaging surface (a light beam having a field angle of 0) and emitted from the periphery of the subject and directed toward the periphery of the screen depends on the lens diameter and the structure of the lens barrel. Due to vignetting, the amount of light decreases (the light beam diameter decreases). As is clear from FIG. 9, the light beam B that is incident from the direction intersecting the optical axis and converges to the point of the maximum image height y _max rather than the light beam A that is incident in parallel to the optical axis and converges to the point where the image height is 0. The amount of light is less. Therefore, generally, the larger the value of the maximum angle of view 2θ, the larger the peripheral light amount drop.

  The second factor that reduces the amount of peripheral light is due to a law called the cosine fourth law. When the angle of view of the lens increases, the brightness of the peripheral portion decreases according to this law even if there is no vignetting. That is, if the light beam emitted from the lens and imaged (incident) on the imaging surface is inclined by α with respect to the optical axis, the illuminance of the image surface decreases in proportion to the cosine fourth power of the inclination α.

  FIG. 10A is a schematic diagram showing the maximum field angle 2θ and half field angle θ of the lens 210 of the interchangeable lens 200. FIG. 10B is a schematic diagram showing the maximum field angle 2θ ′ and half field angle θ ′ of the imaging optical system in which the lens 210 of the interchangeable lens 200 and the lens 310 of the teleconverter 300 are combined. The focal length of the imaging optical system that is a combination of the interchangeable lens 200 and the teleconverter 300 is longer than that of the imaging optical system that includes only the interchangeable lens 200, so that the maximum field angle 2θ ′ is larger than the maximum field angle 2θ. Get smaller.

  As is clear from the above description, there is a certain degree of the problem of the decrease in the amount of peripheral light in the imaging optical system in which the interchangeable lens 200 and the teleconverter 300 are combined, compared to the imaging optical system of the APS-C size interchangeable lens 200 alone. Improved. However, the problem of the decrease in the amount of peripheral light is not completely solved. Therefore, in the apparatus of the present embodiment, the problem is solved by image processing.

As described above, the smaller the image height, the greater the amount of light. Therefore, if the correction coefficient corresponding to the image height of the imaging optical system of the combination of the interchangeable lens 200 and the teleconverter 300 is determined, the peripheral light amount drop can be corrected. The focal length of the lens 210 of the interchangeable lens 200 is f, the magnification of the tele converter 300 is M,: focal length f _T of the entire optical system at the time of wearing the teleconverter 300 is expressed by the following equation.
f _T = f × M

Therefore, the half angle of view θ ′ of the imaging optical system in which the interchangeable lens 200 and the teleconverter 300 are combined is expressed by the following equation.
θ ′ = tan ⁻¹ (y _max / f _T )

  The ROM-C 118 of the electronic camera 100 stores a peripheral light amount drop correction table indicating the relationship between the image height y and the peripheral light amount drop correction value for each value of the half field angle θ ′. Therefore, the CPU-C 117 of the electronic camera 100 selects the peripheral light amount drop correction table corresponding to the half field angle θ ′ after obtaining the half field angle θ ′ by the above-described formula. Then, the CPU-C 117 sets a peripheral light amount drop correction value in the image processing engine 114 based on the peripheral light amount drop correction table. Therefore, the peripheral light amount drop of the image data input by the image processing engine 114 can be corrected by performing vignette correction. Note that the peripheral light amount drop correction coefficient in the peripheral light amount drop correction table also takes into account the correction in the incident angle characteristics of the microlens of the image sensor 107.

  When the user switches to the live view mode of the shooting mode by operating the operation unit 121, the CPU 117 controls the timing generator 113, the image processing engine 114, and the LCD drive circuit 119, for example, a period of 1/30 seconds. Then, the image sensor 112 is driven to update the image displayed on the LCD 120. On the LCD 120 functioning as an electronic viewfinder, a moving image in which MTF characteristics and peripheral light amount drop are corrected is displayed. In the case of the optical finder mode, the above-described imaging device 112 and LCD 120 are not driven.

  When the user half-presses the release switch, the CPU-C 117 sets the shutter speed, aperture value, and ISO sensitivity based on the photometric value obtained from the photometric sensor 104. Then, the CPU-C 117 sets an aperture value (not shown) to a set aperture value. Further, the CPU-C 117 calculates the focus adjustment state using the focus detection signal obtained from the focus detection sensor 108. Based on the calculation result, the CPU-C 117 outputs a lens driving signal for driving the lens 210 to the interchangeable lens 210 via the interface-C110.

  When the user fully presses the release switch, the CPU-C 117 controls the timing generator 113 to drive the shutter 106 at the set shutter speed. Further, the CPU-C 117 determines the gain of the amplifier of the AFE circuit 111 based on the set ISO sensitivity, and sets the gain in the amplifier. At this time, the CPU-C 117 reads the control aperture value and focal length of the interchangeable lens 200 at the time when the release switch is fully pressed, and the subject distance information received from the interchangeable lens 200, and the MTF correction value and the peripheral light amount drop correction value are described above. And the correction values are set in the image processing engine 114.

  An image signal output from the image sensor 107 is sent to the image processing engine 114 via the AFE circuit 111 described above. The image processing engine 114 performs main image processing according to the shooting mode and performs image deterioration correction using the pair of correction values calculated by the CPU-C 117 to generate main image data. When the main image data is generated, the CPU-C 117 causes the compression circuit 115 to perform compression processing of the main image data when the user has set the image compression. If the setting for compressing the image is not made, the CPU-C 117 does not cause the compression circuit 115 to execute the compression process of the main image data. That is, the CPU-C 117 generates RAW data.

  When the main image data is compressed or RAW data is generated, the CPU-C 117 generates an image file. When generating a JPEG file, the CPU-C 117 captures information such as shutter speed, aperture value, ISO sensitivity, file name, photographing date and time, interchangeable lens information such as a model name and characteristic information of the interchangeable lens 200, subject distance information, The type name of the teleconverter 300, teleconverter information such as characteristic information, and a pair of correction values used for image degradation correction are written in the EXIF tag section as EXIF information of the image file. When the image file is generated, the CPU-C 117 writes the image file generated by driving the card interface 122 to the memory card 123. When the data size of the correction value is large, it is recorded in another file format without being recorded in the EXIF tag part.

  The EXIF information is recorded in accordance with the EXIF standard on various pieces of image information attached to an image file. The EXIF information includes the model of the camera that captured the image, an area for recording the serial number of the camera, an area for recording the shooting date and time, an area for recording various shooting conditions, and an arbitrary area that each vendor can use arbitrarily. In the present embodiment, the above-described interchangeable lens information, teleconverter information, and a pair of correction values are recorded in an arbitrary area. FIG. 8 is a diagram showing an example in which various data are stored in such an arbitrary area. Further, when generating image data of RAW data, the CPU-C 117 records the same information as the EXIF information in the header of the image file.

  Hereinafter, an image deterioration correction process executed by the CPU-C 117 in the live view mode will be described with reference to a flowchart shown in FIG. A program for performing each process of FIG. 5 is stored in a memory (not shown), and is activated when an ON signal is input from the power switch of the camera 100.

  In step S1, a request signal for requesting the interchangeable lens 200 to transmit interchangeable lens information is output, and the process proceeds to step S2. In step S2, it is determined whether or not interchangeable lens information has been received. When the interchangeable lens information is received, an affirmative determination is made in step S2 and the process proceeds to step S3. If the interchangeable lens information is not received, a negative determination is made in step S2, and step S2 is repeated until the interchangeable lens information is received.

  In step S3, it is determined whether the teleconverter information is received together with the interchangeable lens information received in step S2. When the teleconverter information is received, that is, when the teleconverter 300 is attached, an affirmative determination is made in step S3 and the process proceeds to step S4. In step S4, based on the received interchangeable lens information and teleconverter information, and the current aperture value and focal length of the interchangeable lens 200, the above-described pair of correction values for correcting image degradation is calculated and stepped. Proceed to S5. In step S5, the pair of correction values calculated in step S4 is set in the image processing engine 114, and the process proceeds to step S20. In step S20, the corrected moving image is displayed on the LCD 120 as an electronic viewfinder.

  When the teleconverter information is not received, that is, when the teleconverter 300 is not attached, a negative determination is made in step S3 and the process proceeds to step S6. In step S6, it is determined whether or not the imaging range of the interchangeable lens 200 corresponds to the APS-C size based on the interchangeable lens information received in step S2. When the imaging range corresponds to the APS-C size, an affirmative determination is made in step S6 and the process proceeds to step S7. In step S7, the imaging range of the image sensor 107 is set to a size corresponding to the imaging range of the interchangeable lens 200, that is, the APS-C size of 23.7 mm × 15.6 mm, and the process proceeds to step S20.

  If the imaging range of the interchangeable lens 200 corresponds to 36 mm × 24 mm, which is the size of the image sensor 107, a negative determination is made in step S6, the process of step S20 is skipped and the process proceeds to step S8. . In step S8, it is determined whether or not the power switch is turned off. If an off signal is input from the power switch, an affirmative determination is made in step S8, and the series of processing ends. If an off signal is not input from the power switch, a negative determination is made in step S8 and the process proceeds to step S9.

  In step S9, it is determined whether or not the release switch is half-pressed. If a half-press signal is input, an affirmative determination is made in step S9 and the process proceeds to step S10. In step S10, focus detection calculation and exposure calculation are performed, and the process proceeds to step S11. If the release switch is not pressed halfway, a negative determination is made in step S9, the process returns to step S20, and the above-described processing is repeated.

  In step S11, it is determined whether or not the release switch has been fully pressed. If the full press signal is input, an affirmative determination is made in step S11 and the process proceeds to step S12. In step S12, an imaging process is executed and the process proceeds to step S14. At this time, the control aperture, focal length, and subject distance information are read, a pair of correction values (MTF correction value and peripheral light amount drop correction value) are calculated as described above, and the pair of correction values are set in the image processing engine. . Therefore, while performing normal image processing, contour emphasis correction and vignetting correction are performed, and an image in which image degradation of the photographing optical system configured by the APS-C interchangeable lens 200 and the teleconverter 300 is corrected is created.

  If the release switch is not fully pressed, that is, if a full-press signal is not input, a negative determination is made in step S12 and the process proceeds to step S13. In step S13, it is determined whether or not the release switch is half-pressed. When the half-press is released, that is, when the half-press signal is not input from the release switch, an affirmative determination is made in step S13 and the process returns to step S9. If the half-press is not released, that is, if a half-press signal is input, the process returns to step S11.

  In step S14, it is determined whether or not the setting is to compress the main image data generated in step S12. If it is set to compress the main image data, an affirmative determination is made in step S14 and the process proceeds to step S15. In step S15, an instruction to JPEG compress the main image data generated in step S12 is output to the compression circuit 115, and the process proceeds to step S16. If it is not set to compress the main image data, a negative determination is made in step S14, and step S15 is skipped and the process proceeds to step S16.

  In step S16, an image file is generated and the process proceeds to step S17. In the case of a JPEG file, various data and information shown in FIG. 8 are recorded in the EXIF tag portion in the image file. In the case of a RAW data file, similar information is recorded in the header of the file. In step S17, the card interface 122 is driven to record the image file generated in step S16 on the memory card 123, and the process returns to step S8.

According to the electronic camera of the first embodiment described above, the following operational effects can be obtained.
(1) A camera body using a 36 mm × 24 mm full-size image sensor 107 is equipped with an imaging optical system composed of an APS-C format interchangeable lens 200 and a teleconverter 300 to enable photographing. That is, the imaging range of the interchangeable lens 200 is expanded by the teleconverter 300 so that the subject image is projected onto the imaging area of the imaging element 107.

(2) When photographing with the above-described photographing optical system, image degradation due to degradation of MTF characteristics and peripheral light loss occurs in the peripheral portion in the photographing screen. This image deterioration was corrected as follows. That is, the CPU-C 117 calculates the MTF correction value and the peripheral light amount drop correction value using the interchangeable lens information and the teleconverter information acquired from the attached photographing optical system. The image processing engine 114 corrects image degradation using these correction values.

  As a result, even when the interchangeable lens 200 that cannot project a subject image over the entire area of the image sensor 107 of the electronic camera 100 is used, a captured image without image deterioration can be acquired. Therefore, even when the image sensor of the electronic camera 100 is enlarged, the APS-C format interchangeable lens 200 that the user currently owns can be used. In addition, since it is possible to correct the image degradation of the captured image that occurs when the teleconverter 300 is mounted, it is possible to capture a high-quality image regardless of the difference in imaging range between the electronic camera 100 and the interchangeable lens 200. .

(3) The CPU-C 117 uses the exchange lens information of the interchangeable lens 200, the teleconverter information of the teleconverter 300, and the pair of correction values used in the image deterioration correction process as the EXIF tag part of the JPEG file or the header of the RAW data file. The image file was generated by writing in the copy. Therefore, image deterioration can be corrected by an external device such as an image processing apparatus having a higher processing capability than the CPU-C 117 using various information written in the EXIF tag part and the header part. Can do.

-Second Embodiment-
In the second embodiment, the electronic camera 100 that has acquired a captured image does not correct image degradation that occurs in the captured image, and uses an external device such as a personal computer (hereinafter referred to as a personal computer) as an image processing apparatus. Correct.

  FIG. 6 is a schematic control block diagram showing an example of a personal computer (hereinafter referred to as a personal computer) 400. The personal computer 400 includes a CPU-P 401, HDD 402, memory card interface 403, operation unit 404, monitor 405, and external interface 406. When the image deterioration is corrected by the personal computer 400, the image processing software is activated and executed by the user. This image processing software is stored in a memory (not shown) in the CPU-P 401 of the personal computer 400. When the user operates the operation unit 404 and is instructed to start the image processing software, the CPU-P 401 starts the image processing software. When the image processing software is activated, the CPU-P 401 reads the image file recorded on the HDD 402 or, if the memory card 123 is inserted, the image file recorded on the memory card 123 via the memory card interface 403. read out.

The CPU-P 401 executes one of the following three processes according to the contents recorded in the EXIF tag part or the header part of the image file. It should be noted that, if there is a description of the header part hereinafter, it includes both the EXIF tag part of the JPEG file and the header part of the RAW data file.
(1) The image deterioration correction process is executed using the MTF correction value and the peripheral light amount drop correction value recorded in the header part described in the camera of the first embodiment.
(2) Based on the lens characteristic information and the teleconverter characteristic information recorded in the header part, an MTF correction value and a peripheral light amount drop correction value are calculated, and an image deterioration correction process for the captured image is executed.
(3) A database in the personal computer 400 is searched based on the lens type name information and the teleconverter type name information recorded in the header part. Then, the lens characteristic information and the teleconverter characteristic information recorded in the database are read to calculate the MTF correction value and the peripheral light amount drop correction value, and the image deterioration correction process for the captured image is executed.

(1) When using the MTF correction value and the peripheral light amount drop correction value recorded in the header portion The CPU-P 401 reads the MTF correction value and the peripheral light amount drop correction value recorded in the header portion of the image file. The pair of correction values are values calculated by the electronic camera 100 as described in the first embodiment. The CPU-P 401 performs contour enhancement processing and vignette correction processing on the image data using the read pair of correction values. As a result, it is possible to correct the MTF degradation caused by the photographing optical system including the interchangeable lens 200 and the teleconverter 300 and the degradation of the photographed image due to the decrease in the amount of peripheral light. The captured image subjected to the image deterioration correction process is displayed on the monitor 405 by the CPU-P401.

(2) When calculating MTF correction value and peripheral light amount drop correction value from lens characteristic information and teleconverter characteristic information CPU-P401 reads the lens characteristic information and teleconverter characteristic information recorded in the header part of the image file. The CPU-P 401 reads the read MTF characteristic data and focal length data of the interchangeable lens 200 (when the interchangeable lens 200 is a zoom lens, focal length data at the time of photographing), MTF characteristic data and magnification data of the teleconverter 300, and at the time of photographing. The MTF correction value and the peripheral light amount drop correction value are calculated using the aperture value data and the subject distance data. These pair of correction values are calculated in the same manner as the CPU-C 117 of the electronic camera 100 in the first embodiment. The CPU-P 401 performs contour enhancement processing and vignette correction processing on the image data using the calculated pair of correction values. As a result, as in the case (1), the captured image is corrected and the captured image subjected to the image degradation correction process is displayed on the monitor 405.

(3) When calculating the MTF correction value and the peripheral light amount drop correction value from the lens type name information and the teleconverter type name information The CPU-P 401 records the lens type name information and the teleconverter type name recorded in the header portion of the image file. Read information. The CPU-P 401 refers to a database stored in a predetermined area of the CPU-P 401 based on the read lens type name information and teleconverter type name information. The database stores the model name of the interchangeable lens 200 and lens characteristic data, and the model name of the teleconverter 300 and teleconverter characteristic data in association with each other.

  The CPU-P 401 uses the MTF based on the lens characteristic data read from the database, the teleconverter characteristic data, the focal length data at the time of shooting, the aperture value data, and the subject distance data read from the header portion of the image file. A correction value and a peripheral light amount drop correction value are calculated. These correction values are calculated in the same manner as the CPU-C 117 of the electronic camera 100 in the first embodiment. The CPU-P 401 performs contour enhancement processing and vignette correction processing on the image data using the calculated pair of correction values. As a result, similarly to the above (1) and (2), the captured image is corrected and the captured image subjected to the image degradation correction process is displayed on the monitor 405.

  The image deterioration correction process is executed using the MTF correction value and the peripheral light amount drop correction value calculated by the electronic camera 100, or the image deterioration is performed using the MTF correction value and the peripheral light amount drop correction value calculated by the personal computer 400. It is possible to select whether to execute the correction process. This selection is performed on the menu screen displayed on the monitor 405 by operating the operation unit 404 by the user. That is, when the correction using the pair of correction values calculated by the electronic camera 100 is selected, the CPU-P 401 executes the above-described process (1). When the correction using the pair of correction values calculated by the personal computer 400 is selected, the CPU-P 401 executes one of the processes (2) and (3) described above.

Hereinafter, the image deterioration correction process executed by the CPU-P 401 will be described with reference to the flowchart shown in FIG. A program for performing each process of FIG. 7 is stored in a memory (not shown), and is read when the image processing software is activated by a user operation.
In step S101, the image file is read and the process proceeds to step S102. In step S102, it is determined whether the MTF correction value and the peripheral light amount drop correction value are recorded in the header portion of the image file read in step S101. If these correction values are recorded, an affirmative determination is made in step S102 and the process proceeds to step S103. In step S103, the flag i = 1 is set and the process proceeds to step S110. If a pair of correction values is not recorded, a negative determination is made in step S102 and the process proceeds to step S104.

  In step S104, it is determined whether or not the lens characteristic data of the interchangeable lens 200 and the teleconverter characteristic data of the teleconverter 300 are recorded in the header portion of the image file. If lens characteristic data and teleconverter characteristic data are recorded, an affirmative decision is made in step S104 and the process proceeds to step S105. In step S105, the MTF correction value and the peripheral light amount drop correction value are calculated based on the recorded lens characteristic data and teleconverter characteristic data, and the process proceeds to step S109.

  If the lens characteristic data and the teleconverter characteristic data are not recorded in the header portion of the image file, a negative determination is made in step S104 and the process proceeds to step S106. In step S106, it is determined whether lens type name information and teleconverter type name information are recorded in the header portion of the image file. If the lens type name information and the teleconverter type name information are recorded, an affirmative determination is made in step S106 and the process proceeds to step S107. If the lens type name information and the teleconverter type name information are not recorded, a negative determination is made in step S106 and the process proceeds to step S111.

  In step S107, it is determined whether lens characteristic data and teleconverter characteristic data corresponding to the interchangeable lens 200 and the teleconverter 300 are recorded in a database stored in a predetermined area of the CPU-P401. If the lens characteristic data and the teleconverter characteristic data are recorded in the database, an affirmative determination is made in step S107, the lens characteristic data and the teleconverter characteristic data are read, and the process proceeds to step S108. In step S108, the MTF correction value and the peripheral light amount drop correction value are calculated based on the lens characteristic data and teleconverter characteristic data read in step S107, and the process proceeds to step S109. If the lens characteristic data and the teleconverter characteristic data are not recorded in the database, a negative determination is made in step S107 and the process proceeds to step S111.

  In step S109, flag i = 0 is set and the process proceeds to step S110. In step S110, image data is used by using one of the pair of correction values recorded in the header portion of the image file, the pair of correction values calculated in step S105, and the pair of correction values calculated in step S108. The image deterioration correction process is performed on the image, and the process proceeds to step S111. In step S111, the image subjected to the image deterioration correction process in step S110 is displayed on the monitor 405, and the process proceeds to step S112.

  In step S112, it is determined whether or not the operation unit 404 has been operated. When an operation signal is input from the operation unit 404, an affirmative determination is made in step S112 and the process proceeds to step S113. If the operation signal is not input from the operation unit 404, the determination in step S112 is negative, and step S112 is repeated until the operation signal is input from the operation unit 404.

  In step S113, it is determined whether or not the operation signal input in step S112 is a signal for instructing execution of the image deterioration correction process. In the case of a signal instructing execution of the image deterioration correction process, an affirmative determination is made in step S113 and the process proceeds to step S114. If it is not a signal for instructing execution of the image deterioration correction process, a negative determination is made in step S113, and the process proceeds to step S128.

  In step S114, an instruction from the user uses the MTF correction value calculated by the electronic camera 100 and the peripheral light amount decrease correction value, and the MTF correction value and peripheral light amount decrease correction value calculated by the CPU-P401. It is determined whether it is a process that has been changed. If it is determined that the instruction is to use a pair of correction values calculated by the electronic camera 100, the process proceeds to step S115. If it is determined that the instruction is to use a pair of correction values calculated by the CPU-P 401, the process proceeds to step S120.

  In step S115, it is determined whether or not the flag i is 1. If the flag i = 1, that is, if the image deterioration correction process has already been executed with the correction value calculated by the electronic camera 100, an affirmative determination is made in step S115 and the process returns to step S112. If the flag i = 0, that is, if the image deterioration correction process has already been executed with the correction value calculated by the personal computer 400, a negative determination is made in step S115 and the process proceeds to step S116. In step S116, it is determined whether the MTF correction value and the peripheral light amount drop correction value are recorded in the header portion of the image file. If these correction values are recorded, an affirmative determination is made in step S116 and the process proceeds to step S117. In step S117, flag i is set to i = 1, and the flow proceeds to step S118. If a pair of correction values is not recorded, a negative determination is made in step S116 and the process proceeds to step S130.

  In step S118, the MTF correction value and the peripheral light amount drop correction value recorded in the header portion of the image file are read, and the process proceeds to step S119. In step S119, image deterioration correction processing is performed on the image data using the pair of correction values read in step S118, and the process returns to step S111.

  Step S120 is a process that proceeds when it is determined in step S114 that the instruction is to execute an image deterioration correction process using a pair of correction values calculated by the CPU-P401. In step S120, it is determined whether or not the flag i is i = 0. If the flag i = 0, the determination in step S120 is affirmative and the process returns to step S112. If the flag i = 1, the determination in step S120 is negative and the process proceeds to step S121.

  Each process from step S121 to step S126 is the same as each process from step S104 (determining whether lens characteristic data and teleconverter characteristic data are present) to step S109 (setting flag i = 0). In step S127, image degradation correction processing is performed on the image data using the MTF correction value and the peripheral light amount drop correction value calculated in step S122 or step S125, and the process returns to step S111.

  In step S128, in which the negative determination is made in step S113, it is determined whether or not the operation signal input in step S112 is a signal for instructing the end of the image processing software. In the case of an operation signal for instructing the end of the image processing software, an affirmative determination is made in step S128, and the series of processing ends. If the operation signal is not an instruction to end the image processing software, a negative determination is made in step S128 and the process proceeds to step S129. In step S129, predetermined processing based on the input operation signal is executed, and the process returns to step S111. In step S130, which has proceeded with negative determinations in step S116, step S123, and step S124, an error message such as “cannot execute the specified image degradation correction process” is displayed on the monitor 404 for a predetermined time. The process returns to step S112.

According to the second embodiment described above, the following operational effects can be obtained.
(1) The CPU-P 401 of the personal computer 400 reads the MTF correction value and the peripheral light amount drop correction value recorded in the header portion of the image file acquired by the electronic camera 100. These correction values are calculated by the CPU-C 117 of the electronic camera 100. Then, the CPU-P 401 uses the read pair of correction values to cause the MTF characteristic deterioration and the peripheral light amount drop due to the photographing optical system including the interchangeable lens 200 and the teleconverter 300 with respect to the read image data. Corrected image degradation. The CPU-C 117 of the electronic camera 100 has a limited bit precision in the calculation due to the reduction of the calculation scale, the speeding up, etc., but the CPU-P 401 of the personal computer 400 can perform the calculation in double. Therefore, since the image deterioration correction process is performed by the personal computer 400 having a higher processing capability than the electronic camera 100, a high-quality image can be obtained. Further, the degree of correction can be finely adjusted according to the user's preference.

(2) The CPU-P 401 of the personal computer 400 reads the interchangeable lens information and teleconverter information of the interchangeable lens 200 and the teleconverter 300 recorded in the header portion of the image file acquired by the electronic camera 100. The CPU-P 401 calculates an MTF correction value for correcting image degradation and a peripheral light amount drop correction value based on the read interchangeable lens information and teleconverter information. Then, the CPU-P 401 performs an image deterioration correction process on the image data using the calculated pair of correction values. Therefore, as described above, since the pair of correction values is calculated using the CPU-P 401 of the personal computer 400 having higher processing capability than the CPU-C 117 of the electronic camera 100, the correction accuracy can be improved.

(3) Which of the MTF correction value and the peripheral light amount decrease correction value calculated by the electronic camera 100 and the MTF correction value and the peripheral light amount decrease correction value calculated by the personal computer 400 is used to determine whether the CPU-P 401 executes the correction process. , Selectable by the user. The electronic camera 100 can generate an image file as a RAW data file or a JPEG file, but the JPEG file image data is subjected to correction processing by the electronic camera 100. When performing correction with higher accuracy, the correction value calculated by the personal computer 400 may be applied to the image data of the RAW data file. When the image deterioration correction process is executed on the personal computer 400, the degree of correction can be finely adjusted. Therefore, it is possible to perform an image deterioration correction process that suits the user's preference.

The embodiment described above can be modified as follows.
(1) In the first embodiment, the interchangeable lens information is MTF characteristic data and focal length data, and the teleconverter information is MTF characteristic data and magnification data. However, the interchangeable lens information may be the model name information of the interchangeable lens 200, the teleconverter information may be the model name information of the teleconverter 300, and the correction value may be calculated from these information. In this case, the electronic camera 100 is provided with a table in the ROM-C 118 in which the model name information of the interchangeable lens 200 is associated with the MTF characteristic data and the focal length data. A table in which the model name information of the teleconverter 300 is associated with the MTF characteristic data and the magnification data is provided in the ROM-C 118. When receiving the model name information of the interchangeable lens 200 and the model name information of the teleconverter 300, the CPU-C 117 reads out corresponding data from the ROM-C 118. Then, the CPU-C 117 calculates the MTF correction value and the peripheral light amount drop correction value based on the read data and sets them in the image processing engine 114 in the same manner as in the first embodiment. Note that the model name information of the interchangeable lens 200 and the model name information of the teleconverter 300 may be input from the menu screen by operating the operation unit 121 by the user.

(2) A pre-stored correction value may be read from the model name information of the interchangeable lens 200 and the model name information of the teleconverter 300. In the case of the electronic camera 100, a table in which the combination of the model name of the interchangeable lens 200 and the model name of the teleconverter 300 and the correction value is associated is provided in the ROM-C 118. The CPU-C 117 reads a correction value corresponding to the combination of the interchangeable lens 200 and the teleconverter 300 from the ROM-C 118 based on the received model name information of the interchangeable lens 200 and the model name information of the teleconverter 300. Then, the CPU-C 117 sets the read correction value in the image processing engine 114. In the case of the personal computer 400, a table in which the combination of the model name of the interchangeable lens 200 and the model name of the teleconverter 300 and the correction value is stored in a database in a predetermined area of the CPU-P401. The CPU-P 401 reads a correction value corresponding to the combination of the interchangeable lens 200 and the teleconverter 300 from the database based on the read model name information of the interchangeable lens 200 and the model name information of the teleconverter 300. Then, the CPU-P 401 uses the read correction value to perform image deterioration correction processing on the read image data. Note that one type of the interchangeable lens 200 does not have one correction value, but for each predetermined classification of the interchangeable lens 200 (for example, wide-angle lens, standard lens, telephoto lens, super telephoto lens, wide-angle zoom) In addition, a correction value as a representative value may be stored in (standard zoom, telephoto zoom classification).

(3) Support for existing users can be implemented via the Internet or a portable recording medium when the camera control program is upgraded. The program of FIG. 7 can also be applied to such version upgrade software. For example, such an image processing program executes a reading process for reading image data and correction data acquired by the electronic camera 100 and a correction process for correcting image deterioration of the read image data using the correction data. To do.

  In addition, the present invention is not limited to the above-described embodiment as long as the characteristics of the present invention are not impaired, and other forms conceivable within the scope of the technical idea of the present invention are also within the scope of the present invention. included.

FIG. 2 is a diagram for explaining a main configuration of an electronic camera 100, an interchangeable lens 200 and a teleconverter 300 that are attached to and detached from the electronic camera 100. 2 is a block diagram of a control system for an electronic camera 100, an interchangeable lens 200, and a teleconverter 300. FIG. It is a performance curve figure explaining a MTF characteristic. It is a conceptual diagram explaining deterioration of the MTF characteristics of the interchangeable lens and the teleconverter in the embodiment. It is a flowchart explaining each process of the image degradation correction | amendment of the electronic camera in 1st Embodiment. It is a block diagram explaining the principal part structure of the image processing apparatus in 2nd Embodiment. It is a flowchart explaining each process of the image degradation correction | amendment of the image processing apparatus in 2nd Embodiment. It is a figure explaining an example of the information recorded on an EXIF tag part. It is a schematic diagram explaining the generation | occurrence | production factor of a peripheral light amount fall. It is a schematic diagram explaining the maximum field angle and half field angle of a lens.

Explanation of symbols

100 Electronic Camera 107 Image Sensor 110 Interface-C
114 Image processing engine 117 CPU-C 200 Interchangeable lens 220 ROM-L 221 CPU-L 222 Interface-L
300 Teleconverter 320 Interface-TC 321 ROM-T
322 CPU-T 323 Interface-TL 400 Personal computer 401 CPU-P

Claims (16)

An image sensor that captures a subject image and outputs an image signal;
Information acquisition means for acquiring interchangeable lens information indicating characteristics of an interchangeable lens mounted on a camera, and converter lens information indicating characteristics of a converter lens mounted on the camera;
Based on the acquired interchangeable lens information and converter lens information, correction data for correcting image degradation of a peripheral portion in a photographing screen caused by a photographing optical system including the interchangeable lens and the converter lens is obtained. A camera comprising correction data generation means for generating. The camera of claim 1,
The interchangeable lens information is interchangeable lens model name information indicating a model name of the interchangeable lens, and the converter information is converter model name information indicating a model name of the converter,
The correction data generation means includes
Correction data storage means for storing the correction data corresponding to the interchangeable lens model name information and the converter model name information;
And a search unit that searches the correction data storage unit for the correction data based on the interchangeable lens model name information and the converter model name information acquired by the information acquisition unit. The camera of claim 1,
The interchangeable lens information is interchangeable lens model name information indicating a model name of the interchangeable lens, and the converter information is converter model name information indicating a model name of the converter,
The correction data generation means includes
Characteristic data storage means for storing optical characteristic data corresponding to the interchangeable lens model name information and the converter model name information;
Search means for searching the optical characteristic data from the characteristic data storage means based on the interchangeable lens model name information and the converter model name information acquired by the information acquisition means;
And a correction data calculating means for calculating the correction data based on the retrieved characteristic data. The camera of claim 1,
The interchangeable lens information is interchangeable lens characteristic data indicating optical characteristics of the interchangeable lens, and the converter information is converter lens characteristic data indicating optical characteristics of the converter lens,
The correction data generation means includes
The correction data is generated based on the interchangeable lens characteristic data and the converter lens characteristic data. The camera according to any one of claims 1 to 4,
A camera, further comprising: an image correcting unit that corrects the image deterioration by correcting the image data generated by the image signal output from the image sensor using the correction data. The camera according to any one of claims 1 to 4,
A camera, further comprising: a file generation unit configured to generate an image file in which the correction data is added to the image data generated from the image signal output from the image sensor. The camera according to any one of claims 1 to 4,
The camera according to claim 1, wherein the correction data includes data for correcting an MTF characteristic of the photographing optical system including the interchangeable lens and the converter lens. The camera according to any one of claims 1 to 4,
The camera according to claim 1, wherein the correction data includes data for correcting a peripheral light amount drop of the photographing optical system including the interchangeable lens and the converter lens. An image sensor that captures a subject image and outputs an image signal, interchangeable lens information indicating the characteristics of an interchangeable lens mounted on the camera, and information acquisition for acquiring converter lens information indicating the characteristics of a converter lens mounted on the camera Means for correcting image degradation of a peripheral portion in a photographing screen caused by a photographing optical system including the interchangeable lens and the converter lens based on the acquired interchangeable lens information and converter lens information. Correction data generating means for generating correction data, image data acquired by the camera, and reading processing for reading the correction data;
An image processing program for executing, on a computer, correction processing for correcting the image deterioration of the read image data using the correction data. A first reading process for reading image data acquired by a camera;
A second reading process for reading interchangeable lens information indicating characteristics of the interchangeable lens mounted on the camera and converter lens information indicating characteristics of the converter lens mounted on the camera;
Based on the read interchangeable lens information and the converter lens information, correction data for correcting image degradation in the peripheral portion in the photographing screen caused by the photographing optical system including the interchangeable lens and the converter lens is obtained. Correction data generation processing to be generated,
An image processing program for executing, on a computer, correction processing for correcting the image deterioration of the read image data using the correction data. The image processing program according to claim 10,
The interchangeable lens information is interchangeable lens model name information indicating a model name of the interchangeable lens, and the converter information is converter model name information indicating a model name of the converter,
The correction data generation process includes:
Based on the read interchangeable lens model name information and converter model name information, the correction data stored in the storage means for storing the correction data corresponding to the interchangeable lens model name information and the converter model name information are searched. An image processing program characterized by including a search process. The image processing program according to claim 10,
The interchangeable lens information is interchangeable lens model name information indicating a model name of the interchangeable lens, and the converter information is converter model name information indicating a model name of the converter,
The correction data generation process includes:
With reference to characteristic data storage means for storing optical characteristic data corresponding to the interchangeable lens model name information and the converter model name information, the interchangeable lens model name information and the converter model name information read in the second reading process A search process for searching for the optical characteristic data based on;
An image processing program comprising: a correction data calculation process for calculating the correction data based on the searched optical characteristic data. The image processing program according to claim 10,
The interchangeable lens information is interchangeable lens characteristic data indicating optical characteristics of the interchangeable lens, and the converter information is converter lens characteristic data indicating optical characteristics of the converter lens,
The correction data generation process includes:
An image processing program that generates the correction data based on the interchangeable lens characteristic data and the converter lens characteristic data. The image processing program according to claim 10,
The second reading process also reads correction data for correcting image degradation of a peripheral portion in a shooting screen caused by a shooting optical system including the interchangeable lens and the converter lens generated by the camera,
An image processing program, further comprising: a selection process for selecting any one of the read correction data and the correction data calculated in the correction data generation process. The image processing program according to claim 9 or 10,
The image processing program, wherein the correction data includes data for correcting an MTF characteristic of the photographing optical system including the interchangeable lens and the converter lens. The image processing program according to claim 9 or 10,
The image processing program characterized in that the correction data includes data for correcting a peripheral light amount drop of the photographing optical system including the interchangeable lens and the converter lens.

Images