JP2010141583A - Imaging device, image data correction method, program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device which improves the operability for long exposure photography while taking into consideration the noise effect due to temperature, an image data correction method, programs and a recording medium. <P>SOLUTION: The imaging device includes: an imaging means which uses an image sensor that converts an object image to electrical signals through photoelectric conversion; a first image data creating means for processing output signals from the imaging means to create image data; a storage means for recording the created image data; a temperature sensor arranged near the image sensor; reference black image data which are acquired, by comparatively long exposure in the state without incident light to the image sensor; a reference data storage means for storing imaging conditions included with the exposure time, temperature and gain at a current time; a correction black image data generation means for generating correction black image data from the reference black image data corresponding to imaging conditions at an actual imaging time; and a second image data creating means for compositing image data at an actual imaging time with the correction black image data that create final image data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device, an image data correction method, a program, and a recording medium, and in particular, an imaging device, an image data correction method, a program, and a recording medium that improve usability in long exposure shooting in consideration of the influence of noise due to temperature. About.

  When shooting very dark subjects such as night scenery and celestial bodies, the sensitivity of the image sensor is increased or the exposure time is increased. Under these conditions, CCD (charge coupled device) In the case of a type imaging device, the influence of noise due to dark current is increased, and the obtained image is also noisy.

  Therefore, in order to cope with this problem, conventionally, photographing is performed by the following method. That is, the image data (first image data) obtained by performing exposure for a predetermined time (several seconds to several tens of seconds) was obtained with substantially the same exposure time in a state where incident light to the image sensor was shielded. Final image data is created by subtracting image data (second image data) (see Patent Document 1). In addition, after normal exposure (main exposure), dummy shooting is appropriately performed with exposure time in a state where the image sensor is shielded from light (acquisition of dark image data), and the imaging data obtained in the main exposure is corrected with the dummy imaging data. An imaging device has also been proposed (see Patent Document 2).

  In recent years, such an imaging method has been incorporated into a general digital camera, and the above-described imaging method may be automatically performed by a single imaging operation (release operation). In addition, there is a model that can perform long exposure with an exposure time of 100 seconds or more, and it has become possible to shoot relatively easily even in scenes that could not be shot.

  However, in the above photographing method, not only the long exposure time is originally doubled, but also in recent cameras with a large number of pixels of the image sensor, the time for reading data from the image sensor becomes long, and the time is also doubled. Therefore, the time until the end of the photographing operation (to obtain the final image) is long, and the photographer sometimes feels inconvenient until the next photographing.

  With respect to such a problem, the second image data is obtained with an exposure time shorter than the exposure time in the first exposure operation, and correction data is created based on the second image data, so that the time is shortened. An apparatus has been proposed (see Patent Document 3). Specifically, when the first exposure time (main exposure) is longer than a predetermined time, the image data obtained by exposing the second exposure time shorter than the first exposure time with the shutter closed is originally If the first exposure time (main exposure) is shorter than the predetermined time, the correction data is generated based on the image data obtained by the first exposure time exposure with the shutter closed. Create

  However, even if the exposure time is shortened, there is no change in performing the exposure operation twice, and the second exposure operation is uncomfortable for the photographer in contrast to the operation that only requires one exposure operation. The photographer is not satisfied with the effect of shortening the time.

Therefore, the image data (second image data (image data obtained in a state where the image sensor is shielded)) obtained by photographing the dark multiple times with the exposure time (shutter speed) and the imaging sensitivity changed before the factory shipment of the camera is stored in the memory. An image pickup device that is stored in a storage device has been proposed (see Patent Document 4). In actual shooting, correction data corresponding to the shutter speed and imaging sensitivity in actual shooting is created from the second image data stored in the memory, and the first image data (image data obtained by main exposure) is created. The final image is obtained by subtracting the correction data from. For this reason, the exposure operation in actual photographing is only required once, and the time is greatly reduced.
Japanese Patent Laid-Open No. 8-51571 JP 2000-125204 A Japanese Patent No. 3998229 Japanese Patent Laid-Open No. 2004-229032

  However, in the imaging apparatus that stores the plurality of second image data in advance, the second image data stored in advance does not consider how noise components are generated due to temperature, but only exposure time and imaging sensitivity. Therefore, in order to create correction data with parameters based only on exposure time and sensitivity, more than twice that amount of data is required, and in this case, the amount of data to be stored increases. In addition, there is a disadvantage that the adjustment process of the camera performed before shipment from the factory becomes long.

  The present invention has been made in view of such a situation, and an object of the present invention is to improve usability in long exposure photography in consideration of the influence of noise due to temperature.

  An image pickup apparatus according to the present invention includes an image pickup unit using an image pickup element that converts a subject image into an electric signal by photoelectric conversion, and first image data generation that generates an image data by processing an output signal from the image pickup unit. Means obtained by a relatively long time exposure in the absence of incident light on the image sensor, a storage means for recording the created image data, a temperature sensor disposed in the vicinity of the image sensor Reference data storage means for storing dark image data and imaging conditions including exposure time, temperature, and gain at that time, and correction dark image data from the reference dark image data according to shooting conditions at the time of actual imaging A correcting dark image data generating means for generating, a second image data generating means for generating final image data by synthesizing the image data at the time of actual photographing and the correcting dark image data; Characterized in that it comprises.

  An image data correction method according to the present invention includes an imaging process using an imaging device that converts a subject image into an electrical signal by photoelectric conversion, and a first image that generates image data by processing an output signal from the imaging process. A data creation step, reference dark image data obtained by exposure for a relatively long time in the absence of incident light to the image sensor in advance, and imaging conditions including at least the exposure time, temperature, and gain at that time From the stored reference data storage unit, the correction dark image data generating step for generating the correction dark image data according to the photographing conditions at the time of image capturing, the image data at the time of image capturing, and the dark image data for correction And a second image data creation step for creating final image data.

  An image data correction program according to the present invention is a first image that creates image data by processing an imaging process using an imaging device that converts a subject image into an electrical signal by photoelectric conversion, and processing an output signal from the imaging process. Data creation processing, reference dark image data obtained by exposure for a relatively long time in the absence of incident light on the image sensor in advance, and imaging conditions including at least the exposure time, temperature, and gain at that time From the stored reference data storage unit, the correction dark image data generation processing for generating the correction dark image data according to the photographing conditions at the time of image capturing, the image data at the time of image capturing, and the dark image data for correction And a second image data creation process for creating final image data.

  The recording medium according to the present invention is a computer-readable recording medium for recording the processing of the image data correction program according to the present invention.

  According to the present invention, usability in long-time exposure photography can be improved in consideration of the influence of noise due to temperature.

  Embodiments of the present invention will be described below in detail with reference to the drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

  This embodiment includes reference dark image data obtained by exposure for a relatively long time in a state where there is no incident light on the image sensor, and the exposure time, temperature, and gain at that time, before the actual shooting. It has a dark image data generation unit for correction that stores image pickup conditions and generates dark image data for correction from reference dark image data in accordance with the shooting conditions at the time of actual shooting (during actual shooting). The image data obtained in actual shooting and the dark image data for correction are combined to obtain final imaging data.

  As a result, the dark image data for correction in the long exposure shooting is created from the data stored in advance, so that the exposure time and the data reading time from the image sensor are doubled compared to the conventional technology. This greatly reduces the waiting time until the next shooting. In addition, since the influence of noise due to temperature is taken into consideration, good correction can be performed without requiring a large amount of memory. In addition, it is conceivable that the correction data can be changed or newly created according to the user's preference, and the degree of freedom of drawing in long exposure photography is expanded.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the number of each figure has attached the same number as much as possible regarding the same member and the same process. Further, a digital still camera will be described as an example of the imaging apparatus according to the present embodiment.

(General configuration)
First, a basic operation of a digital camera which is an example of an imaging apparatus will be described with reference to FIGS. Note that these are examples of a general configuration of the digital camera according to the present embodiment, and the present invention is not limited to this.

  FIG. 1 is an external front view of the digital camera according to the present embodiment. As shown in FIG. 1, a strobe light emitting unit 3, an optical finder 4, a distance measuring unit 5, a remote control light receiving unit 6, a lens barrel unit 7, and a self LED (light emitting diode) 11 are formed on the front of the camera, and further on the side. A release shutter (SW (switch) 1), a mode dial (SW2), and an SD card / battery cover 2 are shown. The SD card is shown as an example of a memory card (recording medium).

  FIG. 2 is an external top view of the digital camera according to the present embodiment. As shown in FIG. 2, a release shutter (SW1) and a mode dial (SW2) are formed on the upper surface of the camera.

  FIG. 3 is an external rear view of the digital camera according to the present embodiment. As shown in FIG. 3, an optical viewfinder 4, AF (Auto Focus) LED 8, strobe LED 9, LCD (Liquid Crystal Display) monitor 10, power source SW 13, and various types of SW 1 to 12 are configured on the back side of the camera.

  FIG. 4 is a functional block diagram of the digital camera according to the present embodiment. The lens barrel unit 7 includes a zoom lens 7-1a for capturing an optical image of a subject, a zoom optical system 7-1 including a zoom drive motor 7-1b, a focus optical system including a focus lens 7-2a, and a focus drive motor 7-2b. 7-2, an aperture unit 7-3 including an aperture 7-3a and an aperture motor 7-3b, a mechanical shutter unit 7-4 including a mechanical shutter 7-4a and a mechanical shutter motor 7-4b, and a motor driver 7 for driving each motor. -5.

  The motor driver 7-5 is driven by a drive command from a CPU (central processing unit) block 104-3 in the digital still camera processor 104 based on inputs from the remote control light receiving unit 6 and operation inputs from the operation unit key units SW1 to SW13. Drive controlled.

  A ROM (read only memory) 108 stores a control program and parameters for control described in a code readable by the CPU block 104-3. When the power of the digital camera is turned on, the program is loaded into a main memory (not shown), and the CPU block 104-3 controls the operation of each part of the apparatus according to the program, and the data necessary for the control, The data is temporarily stored in a random access memory (RAM) 107 and a local SRAM 104-4 in the digital still camera processor (104). By using a rewritable flash ROM for the ROM 108, it is possible to change the control program and parameters for control, and the function can be easily upgraded.

  The CCD 101 is a solid-state imaging device for photoelectrically converting an optical image, and a temperature sensor 131 for measuring the temperature of the CCD is disposed in the vicinity thereof. The F / E (front end) -IC 102 includes a CDS 102-1 that performs correlated double sampling for image noise removal, an AGC 102-2 that performs gain adjustment, an A / D 102-3 that performs digital signal conversion, and a CCD 1 signal processing block 104- 1 is supplied with a vertical synchronization signal (hereinafter referred to as VD), a horizontal synchronization signal (hereinafter referred to as HD), and is controlled by the CPU block 104-3, and drive timing of the F / E-IC 102. It has a TG 102-4 that generates a signal.

  The digital still camera processor 104 performs white balance setting and gamma setting on the output data of the F / E-IC 102 from the CCD 101, and as described above, the CCD1 signal processing block 104-1, which supplies the VD signal and HD signal, The CCD2 signal processing block 104-2 that converts to luminance data / color difference data by filtering processing, the CPU block 104-3 that controls the operation of each part of the device, the data necessary for the control, etc. are temporarily stored. Local SRAM 104-4 to save, USB (Universal Serial Bus) block 104-5 for USB communication with external devices such as personal computers, Serial block 104-6 for serial communication with external devices such as personal computers, JPEG compression / decompression Perform JPEG CODEC block 104-7, A RESIZE block 104-8 for enlarging / reducing the size of the image data by interpolation processing, a TV signal display block 104-9 for converting the image data into a video signal for display on an external display device such as a liquid crystal monitor or TV, and the like. A memory card controller block 104-10 for controlling a memory card for recording the image data.

  The SDRAM 103 temporarily stores image data when the digital still camera processor 104 performs various processes on the image data. The stored image data is, for example, “RAW-RGB image data in a state in which white balance setting and gamma setting are performed in the CCD 1 signal processing block 104-1 from the CCD 101 via the F / E-IC 102. "YUV image data" in which luminance data / color difference data conversion has been performed in the CCD2 signal processing block 104-2, "JPEG image data" that has been JPEG-compressed in the JPEG CODEC block 104-7, and the like.

  The memory card throttle 121 is a throttle for mounting a removable memory card.

  The built-in memory 120 is a memory for storing captured image data even when no memory card is attached to the memory card throttle 121 described above.

  The LCD driver 117 is a drive circuit that drives the LCD monitor 10, and also has a function of converting the video signal output from the TV signal display block 104-9 into a signal for display on the LCD monitor 10.

  The LCD monitor 10 is a monitor for monitoring the state of a subject before photographing, confirming a photographed image, displaying image data recorded in a memory card or the built-in memory 120 described above, and the like.

  The video AMP 118 is an amplifier for converting the impedance of the video signal output from the TV signal display block 104-9 to 75Ω, and the video jack 119 is a jack for connecting to an external display device such as a TV.

  The USB connector 122 is a connector for performing USB connection with an external device such as a personal computer.

  The serial driver circuit 123-1 is a circuit for converting the output signal of the serial block 104-6 described above to perform serial communication with an external device such as a personal computer. The RS-232C connector 123-2 This is a connector for serial connection with an external device such as a personal computer.

  The SUB-CPU 109 is a CPU in which ROM and RAM are built in a single chip, and the output signal from the operation key unit (SW1-13) and the remote control light receiving unit 6 is used as user operation information in the CPU block 104-3 described above. The state of the camera that is output or output from the CPU block 104-3 is converted into control signals for the self LED 11, AF LED 8, strobe LED 9, and buzzer 113, and output.

  The self LED 11 is an LED that indicates that the self timer is operating when the self timer function is executed.

  The AF LED 8 is an LED for displaying an in-focus state at the time of photographing, and the strobe LED 9 is an LED for representing a strobe charging state. The AF LED 8 and the strobe LED 9 may be used for another display application such as when a memory card is being accessed.

  The operation key units (SW1 to SW13) are key circuits operated by the user, and the remote control light receiving unit 6 is a signal reception unit of the remote control transmitter operated by the user. When the camera receives a remote control signal, the above-described self LED 11 is turned on or blinking to indicate that remote control shooting is in operation.

  The strobe circuit 114 is roughly divided into a charging circuit unit and a light emission control unit. The charging circuit unit boosts the battery voltage and charges a capacitor having a capacity of about 100 to 200 μF to about 300V. The light emission control unit controls the amount of light emission by supplying and stopping the energy of the charged condenser to the xenon lamp constituting the strobe light emitting unit 3.

  The voice recording unit 115 includes a microphone 115-3 for inputting a voice signal by a user, a microphone AMP 115-2 for amplifying the input voice signal, and a voice recording circuit 115-3 for recording the amplified voice signal.

  The audio reproduction unit 116 converts an audio reproduction circuit 116-1 that converts a recorded audio signal into a signal that can be output from a speaker, an audio AMP 116-2 that amplifies the converted audio signal, and drives the speaker, and an audio signal. The output speaker 116-3.

(Operation processing)
An operation process when performing long exposure shooting according to the embodiment of the present invention with the digital camera having the above configuration (also simply referred to as a camera) will be described below.

<Creating dark image data for correction>
For example, exposure of a relatively long time is performed in a state where there is no incident light on the image sensor before the camera is shipped from the factory, and the image data (reference dark image data, hereinafter also referred to as reference data) is stored in a built-in memory. The relatively long time is generally several seconds to several tens of seconds, but should be appropriately determined in consideration of the dark current characteristics of the image sensor used in the camera, the exposure time that can be used in the camera, etc. become. The exposure time: t0, ISO sensitivity: K0, and temperature data: T0 are also stored in the built-in memory.

  Since the dark current doubles every time it rises by about 8 ° C, if the temperature change during the t0 time is large and the change in the noise level due to the temperature change during the exposure time cannot be ignored, the above exposure time It is also possible to store data (TS and TE) at the first and last time points, and time data sampled at an appropriate interval. Thereby, corrected dark image data (hereinafter also referred to as correction data) described later can be created with high accuracy.

Next, when actual photographing is performed, correction data is created from reference data stored in advance using the exposure time: t, ISO sensitivity: K, and temperature data: T at that time.
If the reference data is Y0 (t0, K0, T0), the correction data Y (t, K, T) is
Y (t, K, T) = A1 ・ (t / t0) × A2 ・ (K / K0) × A3 ・ 2 ^ (ΔT / 8) × Y0
ΔT = T-T0
It is expressed as Note that the coefficients A1, A2, and A3 of each term are prepared so that correction data optimum for the image sensor can be created, and are determined experimentally.

(First embodiment)
Next, the flow when actually performing long exposure photography will be described with reference to FIGS. FIG. 5 is a flowchart showing operation processing according to the embodiment of the present invention. FIG. 6 is a block diagram showing a characteristic configuration of the digital camera according to the present embodiment.

<Configuration>
As shown in FIG. 6, the digital camera according to this embodiment includes an imaging unit 20 that uses an imaging device that converts a subject image into an electrical signal by photoelectric conversion, and processes output signals from the imaging unit 20 to generate image data. The first image data creation unit 21 for creating the image data, the storage unit 22 for recording the created image data, the temperature sensor 23 disposed in the vicinity of the image sensor, and the comparison in the state where there is no incident light on the image sensor In accordance with the reference data storage unit 24 that stores the reference dark image data obtained by exposure for a long time and the imaging conditions including the exposure time, temperature, and gain at that time, and the imaging conditions at the time of actual imaging, The correction dark image data generation unit 25 that generates correction dark image data from the reference dark image data, and the actual dark image data and the correction dark image data are combined to create final image data. A second image data creating unit 26, characterized in that it comprises a.

<Operation process during actual shooting>
When the release shutter button is pressed, exposure is started (step S1). Exposure time: t, ISO sensitivity: K, and lens aperture, which are the shooting conditions at that time, may be set automatically by the camera's automatic exposure function, but can also be set by the photographer. In the case of long exposure photography, the latter is often the case.

  When the exposure starts, the CPU acquires the temperature data T (step S2), and after the predetermined exposure time t has elapsed (step S3 / Yes), the exposure ends (step S4), and the first image data is created and temporarily stored. (Step S5).

  Next, using the exposure time: t, the ISO sensitivity used: K, and the obtained temperature data: T, correction data is created from the reference data stored in advance by the above equation 1 (step) S6).

  Next, the correction data is subtracted from the first image data to create and record composite image data (final image data) (steps S7 and S8). A process for storing the first image data may be performed (step S9).

(Second Embodiment)
FIG. 7 is a flowchart showing an operation process according to the embodiment of the present invention. In the present embodiment, a case where composite image data is created when the exposure time t is longer than a predetermined time will be described. This is an example, and image data obtained by actual photographing is corrected only when at least one of exposure time, temperature, and gain is larger than a predetermined value among photographing conditions during actual photographing.

  Up to the first image data creation (steps S10 to S14) is the same as steps S1 to S5 in FIG. 5 described above. Next, it is determined whether the exposure time t is longer or shorter than a predetermined time set in advance (step S15). If it is longer (step S15 / Yes), the correction is performed in the same manner as steps S6 to S8 in FIG. Data is created to create a composite image (steps S16 to S18). If it is smaller (step S15 / No), the first image data is recorded as final image data as it is without correcting the noise component (step S19).

  5 and 7, not only the corrected composite image data but also the first image data that has not been corrected is recorded (steps S9 and S19). This allows the user to know the degree of image noise due to dark current and the effect of correction.

(Third embodiment)
FIG. 8 is a flowchart showing the operation processing according to the embodiment of the present invention. Up to the generation of the corrected image data (steps S20 to S25) is the same as steps S1 to S6 in FIG. In this embodiment, it is determined whether the value of the correction data is larger or smaller than a predetermined value. In FIG. 8, it is determined whether or not the luminance level is larger than a predetermined value (step S26). If the luminance level is larger (step S26 / Yes), correction data is created and synthesized as in steps S6 to S8 of FIG. An image is created (steps S27 to S28). If it is smaller (step S26 / No), the first image data is recorded as the final image data without correcting the noise component (step S29).

(Other embodiments)
The user may be able to change the correction data. For example, the amount of correction may be set in the shooting mode menu. Specifically, the correction data (formula 1) obtained by the shooting operation is multiplied by a coefficient α.
Y '= α × Y (t, K, T)
The user only has to input data corresponding to α.

  In addition, a function for newly registering a dark image (an image captured in a state where the lens is shielded from light) obtained by long-time exposure as reference data for correction may be prepared in the shooting mode menu.

  It is also conceivable to provide a temperature sensor for detecting a temperature change of the image sensor on the same chip as the image sensor or in the same package. Thereby, it is possible to accurately detect a dark current that changes with temperature, that is, a noise component of an image.

  As described above, according to each of the above embodiments, since dark image data for correction in long-time exposure shooting is created from data stored in advance, the exposure time and the data reading time from the image sensor are doubled. Compared to the conventional technology, the waiting time until the next shooting can be greatly reduced. In addition, since the influence of noise due to temperature is taken into consideration, a good correction can be performed. Furthermore, by making it possible to change or newly create correction data according to the user's preference, the degree of freedom of drawing in long exposure photography is expanded.

  Note that the program for the CPU to execute the processing shown in the flowcharts of the drawings constitutes a program according to the present invention. As a recording medium for recording the program, a semiconductor storage unit, an optical and / or magnetic storage unit, or the like can be used. By using such a program and recording medium in a system having a configuration different from that of each of the above-described embodiments and causing the CPU to execute the program, substantially the same effects as those of the present invention can be obtained.

  Although the present invention has been specifically described based on the preferred embodiments, it is needless to say that the present invention is not limited to the above-described ones and can be variously modified without departing from the gist thereof.

1 is an external front view of a digital camera according to an embodiment of the present invention. 1 is an external top view of a digital camera according to an embodiment of the present invention. 1 is a rear view of the appearance of a digital camera according to an embodiment of the present invention. 1 is a functional block diagram of a digital camera according to an embodiment of the present invention. It is a flowchart which shows the operation | movement process which concerns on the 1st Embodiment of this invention. 1 is a functional block diagram of a digital camera according to a first embodiment of the present invention. It is a flowchart which shows the operation | movement process which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement process which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

SW1 to SW13 Operation unit Key unit 2 SD card / battery cover 3 Strobe light emitting unit 4 Optical finder 5 Distance measuring unit 6 Remote control light receiving unit 7 Lens barrel unit 7-1 Zoom optical system 7-1a Zoom lens 7-1b Zoom drive motor 7 -2 focus optical system 7-2a focus lens 7-2b focus drive motor 7-3 aperture unit 7-3a aperture 7-3b aperture motor 7-4 mechanical shutter unit 7-4a mechanical shutter 7-4b mechanical shutter motor 7-5 motor Driver 8 AF LED
9 Strobe LED
10 LCD monitor 11 Self LED
DESCRIPTION OF SYMBOLS 20 Imaging part 21 1st image data creation part 22 Storage part 23 Temperature sensor 24 Reference data storage part 25 Dark image data generation part 26 for correction | amendment 26 2nd image data creation part 101 CCD
102 F / E (front end) -IC
102-1 CDS
102-2 AGC
102-3 A / D
102-4 TG
103 SDRAM
104 Digital Still Camera Processor 104-1 CCD1 Signal Processing Block 104-2 CCD2 Signal Processing Block 104-3 CPU Block 104-4 Local SRAM
104-5 USB block 104-6 Serial block 104-7 JPEG CODEC block 104-8 RESIZE block 104-9 TV signal display block 104-10 Memory card controller block 107 RAM
108 ROM
109 SUB-CPU109
113 Buzzer 114 Strobe Circuit 115 Audio Recording Unit 115-1 Audio Recording Circuit 115-2 Microphone AMP
115-3 Microphone 116 Audio reproduction unit 116-1 Audio reproduction circuit 116-2 Audio AMP
116-3 Speaker 117 LCD Driver 118 Video AMP
119 Video jack 120 Internal memory 121 Memory card throttle 122 USB connector 123-1 Serial driver circuit 123-2 RS-232C connector 131 Temperature sensor

Claims (10)

An imaging means using an imaging device that converts an object image into an electrical signal by photoelectric conversion;
First image data creation means for creating image data by processing an output signal from the imaging means;
Storage means for recording the created image data;
A temperature sensor disposed in the vicinity of the image sensor;
Reference data storage means for storing reference dark image data obtained by exposure for a relatively long time in the absence of incident light on the image sensor, and imaging conditions including the exposure time, temperature, and gain at that time;
A correction dark image data generating means for generating correction dark image data from the reference dark image data in accordance with shooting conditions at the time of actual imaging,
An image pickup apparatus comprising: second image data creation means for creating final image data by synthesizing image data at the time of actual photographing and the dark image data for correction. A shooting condition determining means for determining whether at least one of the exposure time, temperature, and gain among the shooting conditions at the time of actual shooting is larger than a predetermined value,
The second image data creation means creates final image data by combining the image data obtained at the time of actual shooting and the dark image data for correction when the judgment means determines that the value is larger than a predetermined value. The imaging apparatus according to claim 1, wherein: A luminance level determining means for determining whether the luminance level of the correction dark image data is greater than a predetermined value;
The second image data creation means creates final image data by combining the image data obtained at the time of actual shooting and the dark image data for correction when the judgment means determines that the value is larger than a predetermined value. The imaging apparatus according to claim 1, wherein:   4. The storage device according to claim 1, wherein the storage unit stores image data obtained at the time of actual photographing and final image data created by the second image data creation unit. The imaging device according to item.   5. The imaging apparatus according to claim 1, wherein the data stored in the reference data storage unit can be changed in accordance with a user operation. 6.   The imaging apparatus according to claim 1, wherein the reference data storage unit stores new reference dark image data and an imaging condition at that time in accordance with a user operation.   The imaging apparatus according to claim 1, wherein the temperature sensor is disposed on the same chip as the imaging element or in the same package. An imaging process using an imaging device that converts an object image into an electrical signal by photoelectric conversion;
A first image data creation step of creating image data by processing an output signal from the imaging step;
Reference data storage in which reference dark image data obtained by exposure for a relatively long time in the absence of incident light on the image sensor and imaging conditions including at least the exposure time, temperature, and gain at that time are stored in advance. A correction dark image data generation step for generating correction dark image data according to the shooting conditions at the time of imaging,
An image data correction method comprising: a second image data creation step of creating final image data by combining the image data at the time of imaging and the dark image data for correction. Imaging processing using an imaging device that converts an object image into an electrical signal by photoelectric conversion;
A first image data creation process for creating image data by processing an output signal from the imaging process;
Reference data storage in which reference dark image data obtained by exposure for a relatively long time in the absence of incident light on the image sensor and imaging conditions including at least the exposure time, temperature, and gain at that time are stored in advance. A correction dark image data generation process for generating correction dark image data in accordance with the shooting conditions at the time of shooting,
An image data correction program that causes a computer to execute a second image data creation process for creating final image data by combining the image data at the time of imaging and the dark image data for correction.   A computer-readable recording medium for recording the processing of the image data correction program according to claim 9.

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