Image shake correction device and method, imaging system, program, and storage medium

Abstract

To more efficiently execute image shake correction by performing positioning composition.SOLUTION: An image shake correction device has: control means that controls image shake correction of reducing an image shake by photographing a plurality of images using imaging means and positioning and combining the plurality of images; acquisition means that acquires information on the resolution and exposure time of an imaging system including the imaging means; and determination means that determines whether to perform the image shake correction based on the information.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image stabilization device and method, an imaging system, a program, and a storage medium, and more particularly to an image stabilization control technique for preventing image degradation by correcting shake caused by vibrations such as camera shake. [Background technology]

[0002] In recent years, many imaging devices and photographing lenses have been equipped with image stabilization mechanisms that can reduce the effects of camera shake on captured images when photographing with a handheld imaging device.

[0003] Several types of image stabilization methods for use in imaging devices have been proposed in the past, including an optical image stabilization method that drives a part of the lens of the imaging optical system or an imaging element in the imaging device so as to offset shake. Patent Document 1 also discloses a method for aligning and synthesizing multiple images captured at a high frame rate. Image stabilization is also performed by combining these methods. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-39223 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, images are captured and aligned and combined without taking into account the shooting magnification and resolution, which means that depending on the shooting magnification and resolution, unnecessary alignment and combination can result in a decrease in image quality or a high processing load.

[0006] The present invention has been made in consideration of the above problems, and has an object to more efficiently carry out image blur correction by alignment and synthesis. [Means for solving the problem]

[0007] In order to achieve the above object, the image stabilization device of the present invention includes a control means for controlling image stabilization to reduce image shake by capturing a plurality of images with an imaging means and aligning and combining the plurality of images, an acquisition means for acquiring information relating to the resolution, focal length, imaging magnification, and exposure time of an imaging system including the imaging means, and a determination means for determining whether or not the resolution will be reduced due to the occurrence of a shake of a predetermined magnitude when imaging is performed under conditions defined by the information, and the control means performs the image stabilization when it is determined by the determination means that the resolution will be reduced, and controls so as not to perform the image stabilization when it is determined that the resolution will not be reduced. Effect of the Invention

[0008] According to the present invention, image blur correction by alignment synthesis can be performed more efficiently. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an imaging system according to an embodiment of the present invention, and a block diagram showing a schematic functional configuration thereof; [Diagram 2] 5 is a schematic diagram illustrating the effect of vibration on system resolution as a function of focal length and exposure time in an embodiment. [Diagram 3] 3 is a schematic diagram illustrating the effect of vibration on system resolution as a function of focal length and exposure time when the system resolution is lower than the example of FIG. 2 in an embodiment. [Figure 4] 3A and 3B are schematic diagrams showing the effect of vibration on the system resolution according to the focal length and exposure time when the imaging magnification is higher than that in the example of FIG. 2 in an embodiment. [Diagram 5]5A to 5C are schematic diagrams showing the effect of shake on the system resolution according to the focal length and exposure time when optical image stabilization is performed in an embodiment. [Figure 6] 4 is a flowchart showing a process of the imaging system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] Hereinafter, an embodiment of the present invention will be described.

[0012] <Image capture system configuration> FIG. 1A is a central cross-sectional view showing an outline of the configuration of an imaging system including an image shake correction device according to this embodiment, and FIG. 1B is a block diagram showing the functional configuration of the imaging system 100. As shown in FIG.

[0013] In this embodiment, a so-called interchangeable lens camera in which the lens unit 2 is detachable from the camera body 1 will be described, but the present invention is not limited to this and can also be applied to an imaging device in which the lens unit 2 is fixed to the camera body 1. Furthermore, the imaging system 100 may be any electronic device equipped with a camera function, and may be, for example, a camera such as a digital camera or digital video camera, a camera-equipped mobile phone, a camera-equipped computer, a game console, or the like.

[0014] The imaging system 100 is composed of a lens unit 2 and a camera body 1, which are detachably connected via electrical contacts 11. An optical axis 4 represents the optical axis of a photographing optical system 3 configured within the lens unit 2. The photographing optical system 3 includes a focus lens, an aperture, a correction lens 9, etc., and is driven by a lens driving unit 13 based on a control signal from a lens system control unit 12.

[0015] The shutter mechanism 17 is driven and controlled by a shutter driving unit 18 so that the image sensor 6 is exposed at a shutter time (exposure time) set by the photographer or determined by the camera system control unit 5.

[0016] The image sensor 6 photoelectrically converts the light image of the subject incident on the imaging surface through the lens unit 2, accumulates electric charges, and outputs an electric signal corresponding to the accumulated electric charges. Then, based on the electric signal output from the image sensor 6, an evaluation amount for focus adjustment and an appropriate amount of exposure are obtained, and the photographing optical system 3 is adjusted, so that an image of the subject with an appropriate amount of light can be formed on the imaging surface of the image sensor 6. Furthermore, the imaging element 6 has an electronic shutter function, and by controlling the timing of resetting and reading out the charges stored in the imaging element 6, it is possible to control the exposure time (charge storage time).

[0017] The image processing unit 19 has an internal analog / digital (A / D) converter, a white balance adjustment circuit, a gamma correction circuit, an interpolation calculation circuit, etc., and acquires the electrical signal output from the imaging element 6, performs image processing, generates image data for recording, and stores it in the storage unit 20. The image processing unit 19 also compresses data such as images, videos, and audio using a predetermined compression method.

[0018] Furthermore, the image processing unit 19 includes a motion vector detection unit 19a that calculates a motion vector, which is an amount of motion based on the captured image, and obtains the amount of image motion by comparing multiple frame images captured by the imaging element 6 and detecting a motion vector. Then, the image processing unit 19 can perform image blur correction by synthesizing images cut out from multiple frame images at different positions based on the motion vector.

[0019] The camera system control unit 5 calculates the amount of shake compensation to reduce the effects of shake based on the signals output from the acceleration detection unit 16 and the angular velocity detection unit 15, and outputs the amount of shake compensation to the shake compensation unit 14 and the lens system control unit 12.

[0020] The lens system control unit 12 outputs a drive command for the correction lens 9 to the lens driving unit 13 based on the shake correction amount from the camera system control unit 5. The lens driving unit 13 performs shake correction that takes into account both angular shake and translational shake by driving the correction lens 9 so as to offset shake in the x direction and y direction shown in FIG.

[0021] Meanwhile, the shake correction unit 14 drives the image sensor 6 to offset the shake based on the shake correction amount received from the camera system control unit 5. The shake correction unit 14 drives the image sensor 6 in the x and y directions shown in Fig. 1(a) to perform shake correction that takes into account both angular shake and translational shake. Furthermore, the shake correction unit 14 drives the image sensor 6 to rotate around the z axis to perform shake correction that takes into account both angular shake and translational shake caused by rotational motion around the z axis.

[0022] In the coordinate axes shown in Fig. 1(a), the z-axis is parallel to the optical axis 4, and the x-axis and y-axis are perpendicular to the z-axis and parallel to each side of the image sensor 6. In order to make the figure easier to see, the origin of the coordinate axes is written outside the image capturing system 100 in Fig. 1(a), but in reality the origin is located at the center of the image sensor 6. Furthermore, the correction method based on the shake correction amount calculated by the camera system control unit 5 is not limited to this method, and other forms may be used.

[0023] The release detection unit 7 detects an open / close signal of a release (not shown) and sends the detected open / close signal to the camera system control unit 5. There are two types of open / close signals detected by the release detection unit 7, and the release detection unit 7 can detect the ON / OFF of switch 1, which is turned ON when the release detection unit 7 is pressed halfway, and switch 2, which is turned ON when the release detection unit 7 is pressed all the way. The operation detection unit 8 detects operations by the photographer on an operation unit (not shown), such as the setting of the shutter time, F-number, mode, and the like.

[0024] The imaging system 100 also has a rear display device 10a provided on the rear surface of the camera body 1, and an EVF (electronic viewfinder) 10b provided within the viewfinder of the camera body 1.

[0025] <Effect of vibration on system resolution> The resolution of the system is determined by the resolution of the lens unit 2 and the number of pixels of the image to be recorded (the resolution of the electrical signal output from the image sensor 6). Even with the same camera, the number of pixels of the image to be recorded varies depending on the size and resolution settings of the image to be recorded, whether crop shooting is ON or OFF, the electronic zoom magnification, etc. In this application, these settings are referred to as shooting conditions related to the number of pixels. Furthermore, the resolution of the lens unit 2 varies depending on the focal length, even with the same lens unit. The resolution of the system is determined by the lower one, so comparing the two, the lower is regarded as the system resolution.

[0026] When the camera body 1 obtains the system resolution, the camera body 1 obtains information indicating the resolution of the lens unit 2 according to the current settings from the lens unit by communication via the mount. Alternatively, information indicating the resolution for each focal length may be obtained from the lens unit 2, and the resolution of the lens unit according to the current settings may be obtained by appropriately obtaining information on the current focal length. Also, information indicating the model number of the lens unit 2 (such as a lens ID) may be obtained from the lens unit 2, and based on this, the camera body 1 may refer to information indicating the resolution for each focal length of the lens unit from a storage means on the camera body 1 side. Note that MTF can be used as information indicating the resolution.

[0027] The same is true when the lens unit 2 acquires the system resolution; information indicating the number of pixels may be acquired directly through communication, or the number of pixels determined by the hardware configuration of the image sensor 6 may be acquired in advance, and the current number of pixels may be acquired by acquiring shooting conditions related to the number of pixels. The current number of pixels may also be acquired from the model number of the camera body 1 and shooting conditions related to the number of pixels. The same is true when an external device other than the camera body 1 or the lens unit 2 (such as a cloud connected to the camera body 1) acquires the system resolution; information indicating the number of pixels is acquired directly or indirectly from the camera body 1, and information indicating the resolution of the shooting optical system is acquired from the lens unit 2, and the system resolution is acquired based on these.

[0028] The magnitude of the effect of shake is determined by the focal length and exposure time, and the longer the focal length and the longer the exposure time, the greater the effect of shake tends to be. Figure 2 is a table showing an example of the relationship between focal length, exposure time, and system resolution when a certain amount of shake (shake amount V1) is applied to imaging system 100 with resolution R1.

[0029] In FIG. 2, the shaded portion indicates a combination where the resolution of the system does not decrease when the shake of the shake amount V1 is applied (that is, a combination with a resolution of R1), and the hatched portion indicates a combination where the resolution of the system decreases due to the shake. Also, the white portion indicates a combination where the resolution of the system significantly decreases due to the shake.

[0030] FIG. 3 shows an example where the resolution R2 of the system is lower than that in FIG. 2 (R2 < R1). When the shake of the shake amount V1 is applied, the number of combinations where the resolution of the system does not decrease increases compared to FIG. 2. This is because the sensitivity to shake is lower due to the originally lower resolution of the system.

[0031] Thus, even when the same magnitude of shake is applied, depending on the original resolution of the system, the combination of the focal length and the exposure time where the resolution of the system does not decrease changes. Utilizing this property, it is determined whether to perform alignment synthesis according to the original resolution of the system, and when performing alignment synthesis, the exposure time (charge accumulation time) per image of the plurality of images used for the synthesis is determined. Thereby, the processing load can be reduced, and the deterioration of the image quality of the image obtained by alignment synthesis can be mitigated.

[0032] Next, the influence of the shooting magnification will be described. When the shooting magnification is low, there is almost no influence of parallel shake. However, when parallel shake occurs, the shake amount becomes large, so the area where the resolution of the system does not decrease becomes narrow. Therefore, it is necessary to consider the shooting magnification and determine whether to perform alignment synthesis and, when performing alignment synthesis, the exposure time per image of the plurality of images.

[0033] FIG. 4 shows an example where the shooting magnification M2 is larger than the shooting magnification M1 shown in FIG. 2 (M2 > M1). When the shake of the shake amount V1 is applied, the number of combinations where the resolution of the system does not decrease is less than that in FIG. 2. Thus, the combination where the resolution of the system does not decrease changes according to the shooting magnification, and the higher the shooting magnification, the fewer the combinations where the resolution of the system does not decrease.

[0034] Next, a case where optical image stabilization is performed using the imaging element 6 and / or the correction lens 9 will be described. When optical image stabilization is performed, the number of combinations for which the system's resolution does not decrease increases compared to when optical image stabilization is not performed. Figure 5 shows an example. In Figure 5, even though other conditions are the same as in Figure 2, there are significantly more combinations for which the system's resolution does not decrease compared to Figure 2. As such, the number of combinations for which the system's resolution does not decrease increases, so it is desirable to use optical image stabilization in combination.

[0035] Therefore, the camera system control unit 5 determines the combination of focal length and exposure time that does not reduce the system's resolution based on the system's resolution, shooting magnification, and optical image stabilization performance, and determines whether to perform alignment and composition, and the exposure time for each of the multiple images if alignment and composition is performed. This reduces the processing load and reduces the deterioration of the image quality of the images obtained by alignment and composition.

[0036] The influence of the shake on the combination of the system resolution, the imaging magnification, and the focal length and the exposure time according to the presence or absence of the optical image stabilization may be stored in the form of a table as described above, or may be stored as a formula. The table and formula are created based on the amount of shake measured in advance. At this time, if the amount of shake is 0, the resolution of the system does not decrease no matter how long the focal length and the time are. Therefore, assuming that a predetermined amount of shake occurs in the imaging system, the amount of decrease in the resolution of the system when the focal length and the exposure time are changed is acquired. The tables acquired in this way are shown in the above-mentioned FIGS. 2 to 5. Also, the amount of shake may be measured by the angular velocity detection unit 15 or the acceleration detection unit 16 during use of the imaging system 100, and the table and formula may be updated appropriately based on the amount of shake to acquire the resolution of the system based on the measured amount of shake.

[0037] 2 to 5 are tables showing how much the system resolution will drop from the original system resolution (which coincides with the resolution when the amount of shake is 0), but it is also possible to use a table or formula showing the system resolution according to the combination of focal length and exposure time when a predetermined amount of shake occurs in the imaging system, regardless of the original system resolution. In this case, a table in which numerical values ​​of the resolution are entered in the color-coded cells of FIGS. 2 to 5 or a formula corresponding to the table is stored. By comparing this table with the original system resolution, information on how much the system resolution will drop can be obtained.

[0038] 2 to 5 are tables in which the degree of resolution degradation is divided into three stages, but the number of stages is not particularly important, and the difference between the original system resolution and the resolution when a predetermined amount of vibration occurs in the imaging system may be held as a numerical value without dividing into stages. Also, the information may be information indicating the resolution as a percentage when the original system resolution is set to 100%. All of these pieces of information are collectively referred to as information indicating the resolution of the imaging system when a predetermined amount of vibration occurs.

[0039] Next, the processing of the imaging system 100 in this embodiment will be described with reference to the flowchart in FIG.

[0040] First, in S101, the camera system control unit 5 detects the system resolution. The system resolution is detected by the camera system control unit 5 receiving MTF information from the lens unit 2, comparing it with the currently set number of recording pixels, and determining the lower resolution as the system resolution. If the imaging system 100 is not of the lens-interchangeable type, the MTF of the imaging optical system is stored in advance in a memory (not shown) in the camera body 1.

[0041] Next, in S102, the camera system control unit 5 detects the focal length and the shooting magnification. The focal length is determined by the characteristics of the shooting optical system, particularly, if a zoom lens is included, by the position of the zoom lens, so position information of the zoom lens is obtained from the lens unit 2. The shooting magnification is determined by the focal length and the distance to the subject, and the distance to the subject can be found using information on the focusing position (for example, position information of the focus lens included in the lens unit 2).

[0042] In S103, the camera system control unit 5 detects the exposure time. In the auto mode, it is a value determined by AE or the like, and in the manual mode, it is a value set by the user through an operation unit (not shown). Furthermore, in S104, information as to whether or not to perform optical image stabilization is obtained.

[0043] Then, in S105, the camera system control unit 5 determines whether to perform alignment and composition. Here, data corresponding to the diagrams shown in Figs. 2 to 5, which have been created in advance, is compared with the conditions acquired in S101 to S104 to determine the effect of shake on the system's resolution. Specifically, if the acquired conditions correspond to the shaded areas, the system's resolution will not decrease even if image blur occurs, so it is determined not to perform alignment and composition. On the other hand, if the conditions do not correspond to the shaded areas, the system's resolution will decrease if image blur occurs, so it is determined to perform alignment and composition.

[0044] If it is determined that alignment and synthesis is to be performed, the process proceeds to S106, and if it is determined that alignment and synthesis is not to be performed, the process proceeds to S107.

[0045] In S106, the camera system control unit 5 determines the exposure time and the number of shots for each of the multiple images used for alignment and composition so that the total exposure time is the exposure time detected in S103. At this time, it is preferable to select a combination of the exposure time and the number of shots within a range in which the resolution of the system does not decrease, in reference to the conditions obtained in S101 to S104. The exposure time when each image is shot is controlled by using the electronic shutter function of the image sensor 6. Here, if the combination is set so that the exposure time is as long as possible within a range in which the resolution of the system does not decrease, the number of shots can be reduced, and therefore the number of images to be composed during alignment and composition, which will be described later, can be reduced. In addition, a combination may be selected such that the total exposure time, which is determined by the combination of the exposure time and the number of shots for each image that can be controlled by the electronic shutter function, is closest to the exposure time detected in S103. After the exposure time and the number of shots are determined, the process proceeds to S107.

[0046] In S107, the camera system control unit 5 determines whether or not shooting has been instructed by the release detection unit 7, and if shooting has not been instructed, the process returns to S101. On the other hand, if shooting has been instructed, the process proceeds to S108.

[0047] In S108, the camera system control unit 5 controls each unit including the image sensor 6 to capture images. At this time, if alignment and composition are not performed, one image is captured with the exposure time determined in S103, and if alignment and composition are performed, the determined number of images are captured with the exposure time determined in S106.

[0048] Then, in S109, the camera system control unit 5 determines whether or not to perform alignment and composition. If not, the process ends, and if so, the process proceeds to S110.

[0049] In S110, the image processing unit 19 detects motion vectors between the multiple images captured in S108 using the motion vector detection unit 19a, and performs alignment and synthesis based on the detected motion vectors to generate an image with reduced camera shake.

[0050] As described above, according to this embodiment, a decrease in the system resolution is judged based on the system resolution, shooting magnification, the presence or absence of optical image stabilization, focal length, and exposure time, and alignment and synthesis is performed if it is judged to be decreased. As a result, if the system resolution does not decrease due to vibration, alignment and synthesis is not performed to reduce the processing load, and if the system resolution decreases due to vibration, alignment and synthesis can be performed to reduce the decrease in image quality.

[0051] Furthermore, when performing alignment and synthesis, degradation in image quality obtained by alignment and synthesis can be reduced by selecting a combination of exposure time and number of shots that does not reduce the resolution of the system.

[0052] <Other embodiments> The above-described embodiment is an example of the present invention, and the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0053] For example, in the above embodiment, when determining whether to perform alignment synthesis in S105, the determination is made based on whether the resolution of the imaging system decreases, in other words, whether the decrease in resolution is 0 or not, but the determination may be made based on whether the amount of decrease is equal to or less than a threshold value or exceeds a threshold value. This threshold value may be set as a percentage (e.g., 5%) of the resolution of the system, or may be set as an amount (e.g., 1 million pixels). If the threshold value is set to 0, the determination is made based on whether a decrease in resolution occurs. If the decrease in resolution is slight but not 0, depending on the accuracy of alignment, etc., not performing synthesis may result in less decrease in image quality, or the decrease in resolution that occurs may be imperceptible or difficult to perceive with the naked eye.

[0054] In the above embodiment, when it is determined in S105 that alignment synthesis is to be performed, the exposure time per one shot is determined in S106 within a range in which the resolution of the imaging system does not decrease. However, S106 may also be configured to set an allowable amount of resolution decrease, and select the exposure time per one shot based on the number of shots taken and the exposure time after synthesis determined in S103 if the amount of decrease falls within this range. For example, if the resolution is 50 megapixels, the exposure time determined in S103 is T, the threshold is 5%, and if the exposure time is 1 / 2T, the resolution is 48 megapixels, and if the exposure time is 1 / 4T, the resolution is 50 megapixels, 1 / 2T may be selected as the exposure time per one shot.

[0055] Also, when it is determined in S105 that alignment and composition is to be performed, a predetermined number of images may be taken and then composited. For example, if the number of images is set to 5, and the resolution is not reduced if the number of images is set to 2, or the resolution is reduced if the number of images is set to 6, five images may be taken and five images may be aligned and composited. In this case, the number of images may be increased compared to when the exposure time per image is determined in consideration of the resolution in S106. However, compared to the conventional form in which alignment and composition are always performed without performing S105, problems such as a decrease in image quality due to unnecessary alignment and composition and a processing load can be reduced.

[0056] On the other hand, although the resolution may be reduced when the number of times of shooting is determined in advance, the degree of the reduction in resolution can be reduced compared to when alignment synthesis is not performed. In this way, when it is determined that alignment synthesis is to be performed, the control of the imaging system can be simplified by performing a configuration in which images are shot a predetermined number of times. Note that the number of times of shooting that is determined in advance does not have to be one, and may be changed according to the shooting conditions. For example, it may be two times for each focal length, five times for a longer focal length, and eight times for an even longer focal length.

[0057] In the above embodiment, only the case where the focal length is changeable has been described, but the present invention can also be applied to an imaging system where the focal length cannot be changed, such as a case where the lens unit and the camera body are integrated and the lens unit does not have a zoom lens. The imaging system where the lens unit and the camera body are integrated can be any type, such as a so-called compact digital camera, a camera equipped in a mobile device such as a smartphone, a surveillance camera, a network camera, etc. In the case of an imaging system where the focal length cannot be changed, the tables shown in Figs. 2 to 5 become one-dimensional, and whether or not to perform alignment synthesis is determined using information indicating the resolution of the imaging system when a shake of a predetermined magnitude occurs according to the exposure time.

[0058] The present invention can also be realized by supplying a program for implementing one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0059] <Summary> The disclosure of this embodiment includes the following configuration.

[0060] (Item 1) a control unit that controls an image blur correction that reduces an image blur by capturing a plurality of images by an imaging unit and aligning and synthesizing the plurality of images; an acquisition means for acquiring information regarding a resolution and an exposure time of an imaging system including the imaging means; a determination unit that determines whether or not to perform the image blur correction based on the information; An image stabilization device comprising: (Item 2) The determination means is the resolution of the imaging system; and determining that the image stabilization should be performed when a difference between a resolution of the imaging system and a resolution of the imaging system when a shake of a predetermined magnitude occurs according to the exposure time is greater than a threshold value; 2. The image stabilization device according to item 1, wherein it is determined that the image stabilization is not to be performed when the difference is equal to or smaller than the threshold value. (Item 3) a storage unit for storing information indicating a resolution of the imaging system when a shake of a predetermined magnitude occurs according to an exposure time; 2. The image stabilization device according to item 1, wherein the determination means determines whether or not to perform the image stabilization based on the information stored in the storage means and the information related to the resolution acquired by the acquisition means. (Item 4) 4. The image stabilization device according to item 3, wherein the control means, when performing the image stabilization, determines an exposure time for capturing each of the plurality of images based on the information stored in the storage means. (Item 5) 5. The image stabilization device according to item 4, wherein the determination means determines, based on the information stored in the storage means and the information related to the resolution acquired by the acquisition means, an exposure time at which a difference between the information stored in the storage means and the information related to the resolution acquired by the acquisition means becomes equal to or smaller than a threshold value, as the exposure time for capturing each of the plurality of images. (Item 6) 6. The image stabilization device according to item 5, wherein, when performing the image stabilization, the control means selects, from among combinations of the number of the plurality of images and the exposure time for capturing each of the plurality of images, the combination being determined according to the exposure time acquired by the acquisition means, a combination that results in the smallest number of the plurality of images. (Item 7) 6. The image stabilization device according to item 5, wherein, when performing the image stabilization, the control means selects, from among combinations of the number of the plurality of images and the exposure time for capturing each of the plurality of images, the combination being determined according to the exposure time acquired by the acquisition means, a combination in which the total exposure time of the plurality of images is closest to the exposure time acquired by the acquisition means. (Item 8) The acquisition means acquires information regarding a focal length, 2. The image stabilization device according to item 1, wherein the determination unit determines whether or not to perform the image stabilization based on information related to the resolving power, information related to the exposure time, and information related to the focal length. (Item 9) The acquisition means acquires information regarding a photographing magnification, 2. The image stabilization device according to item 1, wherein the determination unit determines whether or not to perform the image stabilization based on information related to the resolution, information related to the exposure time, and information related to the shooting magnification. (Item 10) The acquisition means acquires information regarding a focal length and information regarding a photographing magnification, 2. The image stabilization device according to item 1, wherein the determination unit determines whether or not to perform the image stabilization based on information related to the resolution, information related to the exposure time, information related to the focal length, and information related to the shooting magnification. (Item 11) the acquiring means further acquires information regarding the presence or absence of a second image blur correction method different from the image blur correction method; 2. The image stabilization device according to item 1, wherein the determination unit determines whether or not to perform the image stabilization based on information about the resolution, information about the exposure time, and information about whether or not the second image stabilization is performed. (Item 12) a storage unit for storing information indicating a resolving power of the imaging system when a shake of a predetermined magnitude occurs in accordance with different combinations of the exposure time and the presence or absence of the second image blur correction, 12. The image stabilization device according to item 11, wherein the determination means determines whether or not to perform the image stabilization based on the information stored in the storage means and the information related to the resolution acquired by the acquisition means. (Item 13) 13. The image stabilization device according to any one of items 1 to 12, wherein a resolution of the imaging system is the lower of a resolution of a signal read out from the imaging means and a resolution of an imaging optical system that forms an image of light from a subject on the imaging means. (Item 14) An imaging means; An image stabilization device according to any one of items 1 to 13, An imaging system comprising: (Item 15) 15. The imaging system according to item 14, further comprising an imaging optical system for forming an image of light from a subject on the imaging means. (Item 16) Item 16. The imaging system according to item 15, wherein the imaging optical system is detachable. (Item 17) an acquisition step in which an acquisition means acquires information regarding a resolution, a focal length, a shooting magnification, and an exposure time of an imaging system including the imaging means; a determination step in which a determination means determines whether or not the resolution is reduced due to the occurrence of a shake of a predetermined magnitude when photographing is performed under the conditions according to the information; a control step of performing image blur correction when it is determined in the determination step that the resolution will be reduced, and performing control not to perform image blur correction when it is determined that the resolution will not be reduced, The image stabilization method according to the present invention is characterized in that the image stabilization is a process of reducing image shake by capturing a plurality of images by the imaging means, aligning the plurality of images, and synthesizing the images. (Item 18) A program for causing a computer to function as each of the means of the image stabilization device according to any one of items 1 to 13. (Item 19) Item 19. A computer-readable storage medium storing the program according to item 18.

[0061] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0062] 1: camera body, 2: lens unit, 5: camera system control unit, 6: imaging element, 8: operation detection unit, 9: correction lens, 13: lens driving unit, 14: shake correction unit, 19: image processing unit, 19a: motion vector detection unit, 20: storage unit

Claims

1. a control unit that controls image blur correction to reduce image blur by capturing a plurality of images using an imaging unit and aligning and combining the plurality of images; an acquisition means for acquiring information regarding a resolution and an exposure time of an imaging system including the imaging means; a determination unit that determines whether or not to perform the image blur correction based on the information; An image stabilization device comprising:

2. The determination means determining that the image stabilization should be performed when a difference between the resolution of the imaging system and the resolution of the imaging system when a shake of a predetermined magnitude occurs according to the exposure time is greater than a threshold value; If the difference is equal to or smaller than the threshold value, it is determined that the image blur correction is not to be performed.

2. The image stabilization device according to claim 1,

3. a storage means for storing information indicating a resolving power of the imaging system when a shake of a predetermined magnitude occurs according to an exposure time; 2. The image stabilization device according to claim 1, wherein the determining means determines whether or not to perform the image stabilization based on the information stored in the storage means and the information on the resolution acquired by the acquiring means.

4. 4. The image stabilization device according to claim 3, wherein the control means, when performing the image stabilization, determines an exposure time for capturing each of the plurality of images based on the information stored in the storage means.

5. 5. The image stabilization device according to claim 4, wherein the control unit determines, based on the information stored in the storage unit and the information related to the resolving power acquired by the acquisition unit, an exposure time at which a difference between the information stored in the storage unit and the information related to the resolving power acquired by the acquisition unit becomes equal to or smaller than a threshold, as the exposure time for capturing each of the plurality of images.

6. 6. The image stabilization device according to claim 5, wherein, when performing the image stabilization, the control unit selects, from among combinations of the number of the plurality of images and the exposure times for capturing each of the plurality of images, the combination being determined in accordance with the exposure times acquired by the acquisition unit, a combination that results in the smallest number of the plurality of images.

7. 6. The image stabilization device according to claim 5, wherein, when performing the image stabilization, the control unit selects, from among combinations of the number of the plurality of images and the exposure times for capturing each of the plurality of images, the combination being determined in accordance with the exposure time acquired by the acquisition unit, a combination in which the total exposure time of the plurality of images is closest to the exposure time acquired by the acquisition unit.

8. the acquisition means acquires information about a focal length, 2. The image stabilization device according to claim 1, wherein the determining unit determines whether or not to perform the image stabilization based on the information about the resolving power, the information about the exposure time, and the information about the focal length.

9. the acquisition means acquires information regarding the imaging magnification; 2. The image stabilization device according to claim 1, wherein the determining unit determines whether or not to perform the image stabilization based on the information relating to the resolving power, the information relating to the exposure time, and the information relating to the imaging magnification.

10. the acquiring means acquires information about a focal length and information about a photographing magnification, 2. The image stabilization device according to claim 1, wherein the determining unit determines whether to perform the image stabilization based on the information relating to the resolving power, the information relating to the exposure time, the information relating to the focal length, and the information relating to the imaging magnification.

11. the acquiring means further acquires information regarding the presence or absence of a second image stabilization method different from the first image stabilization method, 2. The image stabilization device according to claim 1, wherein the determination unit determines whether to perform the image stabilization based on information about the resolving power, information about the exposure time, and information about whether the second image stabilization is performed.

12. a storage unit for storing information indicating a resolving power of the imaging system when a shake of a predetermined magnitude occurs, in accordance with different combinations of the exposure time and whether or not the second image blur correction is performed, 12. The image stabilization device according to claim 11, wherein the determining unit determines whether or not to perform the image stabilization based on the information stored in the storage unit and the information related to the resolution acquired by the acquiring unit.

13. 2. The image stabilization device according to claim 1, wherein the resolving power of the imaging system is the lower of the resolving power of a signal read out from the imaging means and the resolving power of an imaging optical system that forms an image of light from a subject on the imaging means.

14. The imaging device further comprises a comparison means for comparing a first resolution, which is the resolution of a signal read from the imaging means, with a second resolution, which is the resolution of an imaging optical system that focuses light from a subject on the imaging means; 2. The image stabilization device according to claim 1, wherein the comparison means outputs the lower of the first and second resolutions to the acquisition means.

15. An imaging means; an image stabilization device according to any one of claims 1 to 14; An imaging system comprising:

16. 16. The imaging system according to claim 15, further comprising an imaging optical system for forming an image of light from a subject on said imaging means.

17. 17. The imaging system according to claim 16, wherein the imaging optical system is detachable.

18. an acquisition step in which acquisition means acquires information relating to the resolution, focal length, imaging magnification, and exposure time of an imaging system including the imaging means; a determining step in which a determining means determines whether or not the resolution will be reduced due to the occurrence of a shake of a predetermined magnitude when photographing is performed under the conditions according to the information; a control step of performing image blur correction by a control means when it is determined in the determination step that the resolution will be reduced, and not performing the image blur correction when it is determined that the resolution will not be reduced, The image stabilization method is characterized in that the image stabilization is a process of reducing image shake by capturing a plurality of images with the imaging means, aligning the plurality of images, and combining the images.

19. A program for causing a computer to function as each of the means of the image stabilization device according to any one of claims 1 to 14.

20. A computer-readable storage medium storing the program according to claim 19.

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