JP6261205B2 - Image processing device - Google Patents

Description

  The present invention relates to an image processing apparatus, and more particularly to adjustment of a flow amount in panning using image composition.

  There is panning as a shooting technique that expresses the speed of moving subjects. The purpose of the photographing technique is to make the photographer pan the camera in accordance with the movement of the subject so that the moving subject is stopped in the photographed image and the background flows. In general panning, shooting is performed by adjusting the shutter speed slower than usual in accordance with the moving speed of the subject (main subject) to be shot. However, since the shutter speed is slow, the main subject is often blurred due to camera shake or the difference between the moving speed of the main subject and the panning speed. In view of the above problem, facilitation of panning using an image processing technique is desired.

  For example, in Patent Document 1, a relatively low-sensitivity image and a high-sensitivity image are taken, and among the relatively high-sensitivity images, a partial image corresponding to the main subject region and a relatively low-sensitivity image An imaging device that synthesizes is disclosed. In Patent Document 2, a main subject region is set in an imaging region, and a plurality of exposures are performed in the main subject region while one exposure is performed in a region different from the set main subject region, that is, in the background region. I do. And the imaging device which synthesize | combines the image acquired with respect to each exposure is disclosed.

JP 2012-094984 A JP 2010-166304 A

  However, in the conventional technique disclosed in Patent Document 1 described above, the background flow is expressed by a single image. Therefore, if the main subject cannot be tracked properly, the main subject region of the high-sensitivity image is synthesized. Even so, there is a possibility that the main subject of the low-sensitivity image remains in the vicinity. In addition, since the main subject and the background are photographed at different timings, the shape of the main subject between the two images changes, and the main subject region may not overlap exactly.

  In the prior art disclosed in Patent Document 2, the main subject area is set in advance, and the background flow is expressed by a single image. For this reason, if the main subject goes out of the main subject area during shooting, or if the background enters the main subject area, the boundary between the main subject and the background may become unnatural.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image processing apparatus and an image processing method capable of generating a panning-like image that can smooth the boundary between a main subject and a background.

In order to achieve the above object, the present invention provides a specifying means for specifying a main subject area and a background area different from the main subject area for a plurality of images captured by an imaging means, and the main subject of the plurality of images. A combination unit that aligns the regions and generates a combined image obtained by applying a low-pass filter to the background region and applying a predetermined blurring process; and for the plurality of images, the image of the background region or the shake of the imaging unit Detection means for detecting a movement amount of the background region between the plurality of images based on the information; and the blurring process based on the movement amount of the background region between the plurality of images detected by the detection unit. together possess control means for controlling the amount of blur, and said control means controls the number of taps of said low-pass filter so as to correspond to the blurring amount in the And controlling in response the coefficients in the taps of-pass filter in the region of the composite image.

  According to the present invention, it is possible to generate a panning-like image that can smooth the boundary between the main subject and the background.

1 is a basic configuration diagram of an imaging apparatus according to first and second embodiments of the present invention. The flowchart of the process of CPU concerning Embodiment 1, 2 of this invention. 3 is a flowchart of panning composition relating to the first embodiment of the present invention. FIG. 3 is a first explanatory diagram of calculation of the number of taps of LPF according to the first embodiment of the present invention. FIG. 5 is a second explanatory diagram for calculating the number of taps of the LPF according to the first embodiment of the present invention. The figure which shows the example of calculation of the movement vector in connection with Embodiment 1, 2 of this invention. The figure which shows the example of calculation using the angular velocity of the imaging device concerning Embodiment 1, 2 of this invention. Explanatory drawing of LPF concerning Embodiment 1, 2 of this invention. 6 is a flowchart of panning composition relating to Embodiment 2 of the present invention. Explanatory drawing of calculation of the tap number of LPF concerning Embodiment 2 of this invention. The image figure of the panning composite image concerning embodiment of this invention. FIG. 5 is a diagram showing a UI for panning composition related to an embodiment of the present invention.

(First embodiment)
In order to realize panning using image processing technology, an image in which the main subject is not blurred is necessary. When shooting at a shutter speed at which the main subject does not blur, the background blur width tends to be small, so it is necessary to add a panning effect to the background. In view of the above problems, the present embodiment is characterized in that an effect similar to panning is provided by combining an image in which the main subject is not blurred and an image in which the background is blurred.

  FIG. 1 is a block diagram of an imaging apparatus as an example of an image processing apparatus according to the first embodiment of the present invention.

  The imaging apparatus 100 may be any electronic device having an imaging function, such as a digital camera and a digital video camera, as well as a mobile phone with a camera function, a computer with a camera, and a scanner. In addition, a part or all of the imaging apparatus 100 in the present embodiment can be used as the image processing apparatus in the present embodiment. The image processing apparatus does not necessarily have an imaging function, and may have a function of processing an image output from the imaging element 102 or an image stored in each storage device.

  The optical system 101 includes a lens, a shutter, and a diaphragm. The optical system 101 guides a light beam from a subject to the image sensor 102 and forms an optical image of the subject on the image sensor 102. Information such as the focal length, shutter speed, and aperture value is transmitted to the central processing unit (hereinafter referred to as CPU) 103.

  An image sensor 102 composed of a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like converts an optical image formed by the optical system 101 into an electrical signal. Thereafter, it is digitized through an AD converter and then stored in the primary storage device 104. In this embodiment, the pixel array of the image sensor 102 is a Bayer array of RGB pixels, but the application of the present invention is not limited to this pixel arrangement. For example, it may be an array of complementary color filter pixels, or a functional pixel or the like may be provided for the purpose of color measurement, distance measurement, and the like in addition to such shooting pixels. The electrical gain (hereinafter referred to as ISO sensitivity) of the image sensor 102 is set by the CPU 103.

  An angular velocity sensor 105 such as a gyro sensor detects a shake, converts it as an electrical signal, and transmits it to the CPU 103.

  The CPU 103 functioning as a control unit realizes each function of the imaging apparatus 100 by controlling each part of the imaging apparatus 100 according to an input signal or a prestored program. In the following description, at least a part of the functions realized by the CPU 103 executing the program may be realized by dedicated hardware such as ASIC (Application Specific Integrated Circuit).

  The primary storage device 104 is a volatile device such as a RAM (Random Access Memory), and is used for the work of the CPU 103. Information stored in the primary storage device 104 is used by the image processing unit 106 or recorded on the recording medium 107.

  The secondary storage device 108 is a nonvolatile storage device such as an EEPROM, for example, stores a program (firmware) for controlling the imaging device 100 and various setting information, and is used by the CPU 103.

  The recording medium 107 records data of an image obtained by photographing that is stored in the primary storage device 104. Note that the recording medium 107 can be detached from the imaging apparatus 100, for example, like a semiconductor memory card, and the recorded data can be read out by other devices such as a personal computer. That is, the imaging apparatus 100 has a mechanism for attaching and detaching the recording medium 107 and a read / write function.

  The display unit 109 has a function of displaying information stored for display in the temporary storage device 104 on a display medium such as a liquid crystal according to an instruction from the CPU 103. The present embodiment also has a live view (viewfinder) display function for sequentially displaying at least a part of images continuously acquired from the image sensor 102. In addition, it has a display function such as a GUI (Graphical User Interface) for interactive display and playback and display of recorded images recorded on the recording medium 107 and the like after shooting.

  The operation unit 110 is an input device group that receives user operations and transmits input information to the CPU 103. For example, the operation unit 110 may be an input device using voice, line of sight, etc. as well as buttons, levers, touch panels, and the like. Note that the imaging apparatus 100 according to the present embodiment has a plurality of image processing patterns that the image processing apparatus 106 applies to the captured image, and the patterns can be set as the imaging mode from the operation unit 110. The operation unit 110 also detects an operation on a touch panel included in a display medium used for display by the display unit 109.

  The image processing unit 106 performs image processing called so-called development processing, and also adjusts color tone according to the shooting mode. For example, interpolation processing such as demosaicing processing, white balance processing, correction processing such as aberration and distortion, sharpness, gamma processing, matrix calculation, color conversion processing using a lookup table, and the like can be given. The image processing unit 106 also performs display processing such as resizing and gamma conversion for display on the display unit 109 and recording processing such as encoding and compression during recording on the recording medium 107. The image processing unit 106 also performs processing for generating a panning image in the present embodiment. A plurality of images to be combined and image data generated in the process are stored in the primary storage device 104, for example. Note that at least a part of the functions of the image processing unit 106 may be realized by the CPU 103 as software.

  FIG. 2 is a flowchart relating to processing of the CPU 103 relating to shooting and recording in the panning shooting mode.

  Note that in this embodiment, there are two steps for capturing and recording an image. S1 of the operation unit 110 that appears after that means an instruction to prepare for shooting, and S2 of the operation unit 110 is This means an instruction to capture and record the main image. In the present embodiment, S1 is associated with half-pressing of the shutter button of the operation unit 110, and S2 is associated with full-pressing of the shutter button so that the user can input. In addition, when the operation unit 110 is a touch panel, it is conceivable to change the touch operation on the touch panel, and any operation can be assigned to S1 and S2.

  In step S <b> 201, the CPU 103 receives a user input from the operation unit 110.

  In step S202, the CPU 103 adjusts settings such as the focal length, shutter speed, and aperture value of the optical system 101 based on the input information.

  In step S <b> 203, the CPU 103 adjusts settings such as the ISO sensitivity of the image sensor 102 based on the input information.

  In step S <b> 204, the CPU 103 presents information regarding the changed setting to the user on the display unit 109.

  In step S <b> 205, the CPU 103 receives information on the angular velocity of the imaging apparatus 100 detected by the angular velocity sensor 105. Further, by always executing S205 in the same manner as S202 and S203, information on angular velocity can be embedded as image information together with information on focal length, shutter speed, aperture value, ISO sensitivity, and the like. Then, the reprocessed image in the camera and the post-processing by the PC application are facilitated for the captured image. The information on the angular velocity to be recorded may be the angular velocity itself, the angle moved between images, or the angular displacement.

  The order of S201 to S205 is not limited to this, and the order can be freely changed according to the process.

  In S206, the presence or absence (ON / OFF) of the input of S1 of the operation unit 110 is determined, and the CPU 103 repeats the operations of S201 to S205 unless S1 of the operation unit 110 is input.

  The subsequent processing is processing after S1 of the operation unit 110 is input (ON) in S206.

  In step S <b> 207, the CPU 103 measures brightness using a photometric sensor that is a part of the optical system 101. In the case of an AE (Auto Exposure) mode in which automatic exposure control is performed, exposure is automatically adjusted using the shutter speed, aperture value, and ISO sensitivity.

  In S208, in the AF (Auto Focus) mode in which automatic focus adjustment control is performed, the CPU 103 measures the subject distance using a distance measuring sensor disposed in a part of the optical system 101 or in the image sensor 102, and Focus adjustment is performed based on the defocus amount.

  Note that the order of S207 and S208 is not limited to this, and the order can be freely changed according to the processing.

  In S209, the presence or absence (ON / OFF) of the input of S2 of the operation unit 110 is determined, and the CPU 103 repeats the operations of S201 to S208 unless S2 of the operation unit 110 is input. Further, it may be configured to detect whether or not the input of S1 of the operation unit 110 is continued in S209 and to return to step S201 when the input of S1 of the operation unit 110 is not performed (OFF). Good.

  The subsequent processing is processing after S2 of the operation unit 110 is input (ON) in S209.

  In S210, in response to the shooting instruction in S2 from the operation unit 10, the number of images necessary for the panning process is shot. At this time, in the panning mode, it is assumed that the user pans the imaging device 100 (or a part thereof including the imaging device 102) to obtain a panning effect. The number of images used for panning may be set in advance by the user, or, as will be described later, is a number automatically calculated from the setting of the speed of the main subject, the amount of panning, the degree of blurring of the background area, etc. There may be.

  In S211, the image processing unit 106 performs the development process as described above on the image data captured in S210.

  In S212, the CPU 103 detects a main subject region by detecting a movement vector for each divided region between a plurality of images, and performs alignment processing in the detected main subject region. Here, in the present embodiment, the main subject area refers to a subject area that is detected separately from a background area, which will be described later, in the captured image, and the subject in the area is composed of, for example, a plurality of persons. It may be. In the present embodiment, an area of a moving subject (moving body area) is detected as a main subject area for panning. That is, a subject (stationary object) that is stationary in a plurality of shootings outside the subject region is treated as a background. However, as described above, when it is assumed that shooting is performed by panning, a subject that moves corresponding to the panning amount in the opposite direction of the panning direction is stationary when compared between images. The subject. A subject that moves in the panning direction in the same manner as the panning amount is determined as a moving object. Details will be described later. On the other hand, when it is assumed that shooting is performed with a tripod or the like fixed, an area where a motion vector can be largely detected is considered as a main subject area.

  In S213, the CPU 103 combines the plurality of images that have been aligned so that the main subject areas match in S212 by the image processing unit 106, and generates a composite image as a panning image. A plurality of methods are conceivable as a method for generating a composite image having a visual effect similar to that of panning. In the present embodiment, alignment is performed so that the main subject region matches between a plurality of captured images, addition is performed, and blurring processing is performed on a background region different from the main subject region of the combined image. Further, the method for generating the final composite image is not limited to this. For example, the background area of a plurality of images obtained by shooting is subjected to a blurring process (filtering process, etc.) with a blurring amount (number of taps) based on the amount of movement of the background between the images, and a plurality of images in which the main subject area is shot The images may be aligned so as to match, and may be combined by averaging. Here, the amount of movement of the background can be calculated from the angular velocity obtained by the angular velocity sensor 105. Further, an image obtained by further combining the image obtained by blurring the combined image as described above and the image before blurring may be used as the final combined image. An image of the synthesized image is shown in FIG. An image 1104 is an image diagram of an image generated by performing synthesis in the above steps based on the images 1101, 1102, and 1103. The moving object, the main subject vehicle, is clearly visible, and the background trees are reflected.

  Returning to FIG. 2, in S214, the CPU 103 displays the image data obtained by performing the display processing by the image processing unit 106 on the combined image data generated in S213 and the image data before combining that is the original image data. To display.

  In step S215, the CPU 103 stores the image data obtained by performing encoding processing, compression processing, and the like on the composite image data generated in step S213 on the recording medium 107 and the original pre-combination image data. Record. In the present embodiment, as the setting of the recording image, it is possible to set recording of a RAW image that has not been subjected to development processing or the like, or recording of a JPEG image that has been subjected to development processing and conforms to the standard. Depending on these settings, the development process in S210 and the encoding process in S216 may not be applied.

  In this embodiment, the main subject detection process in S212 and the panning composition process in S213 are performed on the image after the development process in S211. However, the present invention is not limited to this, and the image before the development process is processed. Each process can also be applied.

  FIG. 3A is a flowchart showing details of detection of the main subject area (moving object area) and registration processing between images in the main subject area performed in S212 of FIG.

  In step S301, the CPU 103 sets a search block obtained by dividing an image into a plurality of areas, and detects a movement vector between images in units of search blocks.

  In S302, the CPU 103 counts the number of detected movement vectors that are substantially the same vector. FIG. 3B shows a state after counting, in which the horizontal axis represents the vector size and the vertical axis represents the number (frequency). The horizontal axis distinguishes the direction of the movement vector from 0 as a boundary. First, based on the movement amount 310 of the background based on the shake detected by the angular velocity sensor 105 (that is, movement information of the imaging means between a plurality of images), the movement vector is separated from the movement amount of the background as shown in the figure. The object component 311 and the background component 312 in the vicinity of the background movement amount are classified. Next, the movement vector having the largest number among the movement vectors of the classified main subject component 311 is set as the main subject vector 313.

  Here, it is possible to classify the main subject and the background from the histogram of the movement vector without using the shake information detected by the angular velocity sensor 105. For example, when panning is performed by panning shooting by the user, it is assumed that the main subject is almost near the center in each image, and the vector size is close to zero and exists in a continuous area in the image. The region corresponding to the movement vector to be considered is considered as the main subject region. However, depending on the size of the search area of the movement vector, there is also an erroneous detection of the movement vector. Therefore, the main subject and the background can be classified more accurately by referring to the shake information from the sensor as in the above embodiment.

  As described above, in S303, the CPU 103 identifies a movement vector corresponding to the main subject area. In the present embodiment, a signal from the angular velocity sensor 105 at the time of capturing each image is converted into a movement amount of the imaging device 100 between the images, and a background movement amount between the target images is estimated, and the image is stationary. Classify the background movement vector and other vectors. When the movement vector corresponding to the background is excluded, the movement vector having the largest number is estimated as the movement vector corresponding to the main subject. In this embodiment, the angular velocity of the imaging device 100 is detected by the angular velocity sensor 105, but the present invention is not limited to this, and acceleration and displacement are detected using an acceleration sensor, other position measuring sensors, and the like. You may convert into the movement amount between images. In this embodiment, since it is assumed that shooting is performed with panning, the background movement vectors are classified by the above method as a method for determining the movement vector of the main subject. As described above, when the background movement vector is not classified by the signal of the angular velocity sensor 105, the second most frequent movement vector is determined as the main subject movement vector. Alternatively, the movement vector of the main subject is estimated by detecting whether an area having the movement vector exists with a certain amount of clumps. When it is assumed that shooting is performed with the imaging apparatus 100 fixed using a tripod, the largest number of movement vectors on the image can be simply determined as the movement vector of the main subject. In addition, as the movement vector, the horizontal direction and the vertical direction of the image may be handled separately, or a combined vector may be handled.

  In step S304, the CPU 103 performs image alignment by shift movement in the memory of the primary storage device 104 so that the position of the main subject matches the reference image based on the value of the movement vector of the main subject.

  Finally, in S305, it is determined whether or not there are remaining images to be aligned. That is, as long as the target image to be aligned remains, the process returns to S301 to perform the alignment of the next image, and when the alignment of all the images is completed, the process of S212 in FIG.

  FIG. 3C is a flowchart showing details of the composition process (panning shot) performed in S213 of FIG.

  In S321, the CPU 103 combines the plurality of images aligned in S304 in FIG. 3 to express the change in the main subject over time even in the main subject while suppressing blurring. Create a composite image. For example, when a running person is a main subject, the movement of a person's hand can be expressed by synthesis. This first composite image is mainly used for the main subject area in the final composite image.

  In S322, the CPU 103 calculates the number of taps of a low-pass filter (hereinafter referred to as LPF) to be applied to the image synthesized in S321. As will be described in detail later, the number of taps of the LPF is calculated so as to compensate for the number of pixels that are insufficient to flow the background, according to the amount of movement of the background to which the flowing image effect is applied. . In addition, when there is a manual or automatic designation about the degree of background flow from the user, the number of taps for obtaining the blur amount corresponding to the designated degree of flow is calculated.

  In step S323, the CPU 103 generates a second composite image expressing the background flow by applying the LPF of the number of taps to the image combined in step S321. Here, in the present embodiment, LPF is applied to the first combined image combined in S321, but the second combined image is generated by applying LPF to each image before combining to generate the second combined image. May be.

  In step S324, the CPU 103 combines the first combined image combined in step S321 and the image subjected to LPF processing in step S323 using information on the main subject area detected in step S212 in FIG. At this time, the main subject area is synthesized mainly using the first synthesized image synthesized in S321, and the background area is synthesized mainly using the second synthesized image generated in S323. A third composite image is generated.

  Next, the concept of calculating the number of taps of the LPF in S322 in FIG. 3C will be described with reference to FIGS. Since general panning is performed with one exposure, the background changes so as to flow continuously. That is, for example, the background 403 in the first image 401 in FIG. 4 and the second image 402 immediately thereafter is blurred when the first image and the second image are combined. The background in the composite image 404 is desirable. However, if the images 401 and 402 are simply combined, the background is displayed discretely as in the combined image 405. Therefore, in the present embodiment, the background does not exist in the portion represented by the amount of movement 406. The deficient pixels in the background 403 are compensated for, and are connected and displayed as an image 404.

  In other words, in the present embodiment, the background is appropriate by using a filter corresponding to the panning direction (predetermined direction) of the camera with the number of taps that compensates for insufficient pixels between the discrete backgrounds displayed in the composite image 405. The image that is flowing in is generated. For example, when the background movement amount 406 is 5 pixels, a low-pass filter of 1 × 5 pixels or more is set. Also, the reference pixel on the filter is set to the right end according to the panning direction, for example, if panning is in the left direction. By setting the filter in this way and performing the filtering process on the background area of the composite image, it is possible to generate a composite image of the panning style in which the background is connected in an appropriate direction.

  In the present embodiment, the following control is performed in the composite image in order to obtain the same effect as when panning is performed at a predetermined shutter speed (referred to as an equivalent shutter speed here) set by the user. Do it. That is, in order to obtain a composite image with an equivalent shutter speed set by the user, the composite number is determined according to the number of images to be taken (or frame rate) per unit time. For example, when shooting an image at a speed of 60 sheets per second, it is generated from one image when the corresponding shutter speed set by the user is 1/60 seconds or less, and from three images when it is 1/20 seconds. To do. Thus, the number of combined images is determined so that the total shooting time corresponds to the equivalent shutter speed. Even if the number is equal to or smaller than the number corresponding to the equivalent shutter speed, the blur amount of the background area may be increased accordingly.

  For example, in FIGS. 5A and 5B, FIGS. 5B and 5C respectively show images obtained by combining two images that are temporally continuous, taken by a user panning with the vehicle in the center as the main subject. Yes. FIG. 5B shows a composite image of the first photographed image and the second photographed image when the photographed images are arranged in time series. FIG. 5C shows the second photographed image and the third photographed image. A composite image of the captured image is shown. FIG. 5 (d) shows an image taken on the third sheet, and the background tree drawn with a dotted line flows and appears when the user takes a panning shot while exposed while panning in the conventional method. The place of the wax is shown.

  FIG. 5A is a diagram for explaining the concept of setting the number of taps of the LPF. Now, 1/20 second is set as the equivalent shutter speed of the final composite image by the user, and 3 at a speed of 60 sheets per second. Suppose that a picture was taken. In the figure, the reference pixel 501 at a predetermined position on the background 403 is changed as the reference pixel 501, the reference pixel 502, and the reference pixel 503 in the first, second, and third photographing. . At this time, it is necessary to interpolate the interval 504 between the reference pixel 501 and the reference pixel 502 and the interval 505 between the reference pixel 502 and the reference pixel 503 so that the pixels are connected. In addition, when a picture is taken while being exposed even during actual panning at a set equivalent shutter speed, the background flows between the reference pixel 503 and the reference pixel 506, and therefore the interval 507 between the reference pixel 503 and the reference pixel 506 is also set. It is necessary to interpolate so that the pixels are connected. Therefore, an LPF having the number of taps having an interval 504 (or interval 505 or interval 507) is applied to the combined image as shown in FIG.

  The method of calculating the number of taps 504, in other words, the method of calculating the amount of movement of the background between images, uses either the method of analyzing a plurality of images as described above or the method of using the angular velocity of the imaging device 100 for measurement. May be. In the method of analyzing a plurality of images, as in steps S301 to S303, a representative movement vector of the background is calculated as the amount of movement of the background from the movement vector histogram for each region. FIG. 6 is an image diagram showing that a movement vector 604 is calculated as a movement vector of the background 603 from the histogram as shown in FIG. 3B between the image 601 and the image 602.

  Here, a method for calculating the amount of movement of the background from the angular velocity of the imaging apparatus 100 will be described with reference to FIG.

  FIG. 7 shows how the stationary background moves on the imaging surface when the camera is rotated by panning or the like.

  When the imaging device 100 is panned like 701 and a stationary subject 702 is photographed, the stationary subject 702 moves from the position 702 ′ to the position 702 ″ on the imaging element 102.

  Using Equation 1, the amount of movement of the stationary subject 603 on the image is calculated.

  As shown in Expression (1), the moving amount 705 of the stationary subject, that is, the background can be calculated from the moving angle 703 of the imaging device 100 by panning and the focal length f of the optical system 101. The moving angle 703 is calculated using the angular velocity ω of the imaging apparatus 100 detected by the angular velocity sensor 105, the number of images taken per unit time (frame rate fps), and the number of images n between images to be sampled. Finally, the background movement amount 705 on the image is converted into pixels using the pixel pitch pp. As described above, the number of taps corresponding to the background movement amount 705 is handled as the number of taps of the LPF used for the current blurring process.

  The movement angle 703 may be accurately calculated every time from the angular velocity corresponding to each image, or may be calculated collectively from the average angular velocity of all images.

  Next, details of the LPF processing for the composite image in S323 of FIG. 3 will be described with reference to FIG.

  The main subject of the image 801 and the image 802 is 803. In the main subject recognition in S212 of FIG. 2, the main subject region map obtained by binarizing each region in the image based on the subject movement vector is accurately at the boundary between the main subject and the background as in the main subject region map 804. It shall be separable. At this time, in the image composition in S324, it is almost unnecessary to use the pixels of the main subject area in the image after applying the LPF, that is, the background image 805. Therefore, the main subject region is extracted by the above-described method, and an image obtained by applying the LPF of the tap number set as described above to the region excluding the main subject region, that is, the pixels in the background region, is used as the background image 805. And

  Finally, in S324, the main subject region is selected from the main subject image (first composite image) 806, the background region is selected from the background image (second composite image) 805, and the final composite image is selected. Is generated. In this method, when the main subject is correctly extracted, there is almost no afterimage around the main subject, but when the main subject is not correctly extracted, the boundary between the main subject and the background is unnatural. There is a possibility. As a countermeasure to make the boundary unnatural, it may be possible to perform a blurring process such as a filter that blurs the boundary between the main subject area and the background area as a boundary process. Only the blur processing is applied, and it still looks unnatural. As an example in which the main subject region cannot be extracted well, for example, there is a case where there is almost no contrast difference between the main subject and the background. In addition, there is a possibility that the movement vector is not obtained well and the background is extracted as the main subject area, or a part of the main subject is classified as the background area. Therefore, there is a possibility that the subject to select the subject to be applied.

  The following method can be adopted for this method. That is, using the information of the detected main subject region, pixels in the main subject region are interpolated using pixels around the main subject region, and an image obtained by applying LPF is set as a background image 807. Then, like the main subject area map 808, the boundary between the main subject and the background is blurred, and in step S324, the main subject image 806 and the background image 807 are weighted according to the main subject area map 808 while weighting the pixel values of the main subject area. It can also be synthesized while mixing.

  However, even in this method, when the main subject area has a shape like the main subject area 809 in which the main subject area is omitted, there is a possibility that a background is inserted or reflected in the main subject area of the combined image. .

  Therefore, the following method is used in the present embodiment. First, the main subject area map 804 is blurred as in the main subject area map 810 by blurring processing. As a result, even when a void has occurred as in the main subject region map 809, the influence of the void can be reduced as in the main subject region map 810. Then, the main subject image (first composite image) 806 is subjected to LPF using the pixel value of the main subject region in the main subject region map 810 as shown in Equation 2 as a coefficient. In this way, a background image (second composite image) 811 is created in which the pixels of the main subject region are difficult to spread around while the entire image is blurred. Finally, in S324, the panning image (third composite image) 812 is generated by combining the main subject image 806 and the background image 811 with the pixel value of the main subject region map 810 as a weight and mixing them. This technique not only suppresses the pixels of the main subject area from spreading to the surroundings, but is also effective in the case of a void. Since blur processing is performed with the LPF of the coefficient in the tap as shown in Equation 2, the surrounding pixels recognized as the main subject region are not used much, and the pixels in the low contrast region are also simply blurred. Inconspicuous. Furthermore, by combining with the main subject image, the unnaturalness of the area misidentified as the main subject area becomes less noticeable.

  As described above, in the present embodiment, the unblurred image is aligned and combined, and the blurring process is performed to blur the background. By doing so, it is possible to provide a panning-like composite image having the same effect as a photographed image at a shutter speed that is difficult to shoot in general panning. Further, when combining a plurality of images, a more effective panning-like composite image can be provided by performing a blurring process on the background according to the amount of movement of the background relative to the main subject. In addition, by controlling the number of images to be combined in accordance with the shutter speed equivalent to the panning desired by the user, a more effective panning-like composite image can be provided.

(Second Embodiment)
In the first embodiment, the setting by the user using the operation unit 110 is the shutter speed of the panning shot corresponding to the composite image (the shutter speed when shooting with the conventional panning shot). In the embodiment, the user can set the amount of the background to be flowed as the effect of panning on the final image. For example, the user performs shooting by selecting an effect amount from three effects of large, medium, and small that are set in advance. For example, the effect amount is changed by setting the blur width in the form of n pixels for the small effect, 2n pixels for the effect, and 3n pixels for the large effect. The effect amount can be set to an arbitrary width in advance by the user.

  Since the configuration of the imaging apparatus 100 is the same as that of the first embodiment, description thereof is omitted.

  FIG. 9 is a flowchart showing details of the panning composition performed in S213.

  In step S <b> 901, the CPU 103 combines the plurality of images aligned in step S <b> 212 to generate an image that expresses changes in the main subject over time while suppressing blurring.

  In step S <b> 902, the CPU 103 initializes a variable that stores the total flow amount currently applied to the target image.

  In S903, the CPU 103 calculates the number of taps of the low-pass filter applied between the two images aligned in S212 as a calculated value. Details of the tap count calculation method will be described later.

  In S904, when the LPF having the calculated number of taps is applied to the current target image, the flow amount of the composite image obtained by combining up to the current target image is the above-described effect amount (flow amount) set by the user. ) Is not exceeded by a comparison operation between the total flow amount + calculated value and the set value.

  If the total flow amount + calculated value exceeds the set value, the difference between the set value and the total flow amount is newly set as the calculated value in S905 so that the set value is not exceeded.

  In step S <b> 906, the CPU 103 compensates for the deficient pixels by applying LPF to the previously captured image of the two images.

  In S907, the CPU 103 adds the current LPF flow rate to the total flow rate.

  In S908, it is determined whether the total flow amount reaches the set effect amount.

  If the total flow amount does not reach the set effect amount, the operations of S903 to S907 are repeated for the next image in S909.

  The subsequent processing is processing after the total flow amount reaches the set effect amount in S908.

  In step S910, the CPU 103 generates an image representing the background flow by combining all the images subjected to the LPF in steps S903 to S908. In the present embodiment, LPF processing is performed on each captured image before combination in S906 with the number of taps determined in S903, and then combined in S910. However, for example, the maximum value of the number of taps determined in S903 may be held, and the LPF process may be performed on the image before the adjustment in S905 with the maximum number of taps after synthesis.

  In step S911, the CPU 103 combines the alignment composite image combined in step S901, that is, the main subject image (first composite image) and the LPF composite image (second composite image) combined in step S910, that is, the background image. To do. As a result, a third composite image having the same effect as the panning is created.

  Details of a series of processing relating to LPF in FIG. 9 and S902 to S910 will be described with reference to FIG. FIG. 10A is a diagram showing the concept of the number of taps of the LPF.

  When the background 1001 changes to the background 1002, the background 1003, and the background 1006, and the overall flow amount (total flow amount) is 1008, interpolation is performed between the background movement amount 1004 and the background movement amount 1005. There is a need. However, since the final target value (set value) is the total flow amount 1008, if interpolation is performed so as to fill the entire space between the background 1003 and the background 1006, the total flow amount becomes the set value 1008 of the user's flow amount. It will be over. This situation corresponds to the case where S904 in FIG. 9 is YES. In such a case, between the background 1003 and the background 1009, the target value of the LPF tap number is changed to 1009 as shown in FIG. 10A (S905), and only 1007 between 1003 and 1009 is changed. Interpolate.

  1007 can be obtained from the difference between the total flow amount 1008 that is the final target value and the flow amounts 1004 and 1005 in the background 1001 to the background 1003. In this way, in S907, by accumulating the number of taps (blurring amount) of the LPFs up to the current image to be processed as the current flow amount, the change in the total flow amount with the increase in the number of combined images is grasped. Enables panning composition with appropriate number of sheets and appropriate effect amount.

  Other configurations and flows are basically the same as those in the first embodiment. However, as described above, in the first embodiment, the number of taps of the LPF is only for compensating for the insufficient pixels, but in the present embodiment, the number of taps is controlled based on the effect amount of the panning.

  Since the speed of the main subject rarely changes in a short time, the average value or the maximum value of the movement amount between the background images is calculated, and from the first image to the last image, You may apply LPF of the same number of taps using a value. If this method is used, the number of images that can be combined can be calculated first, which leads to faster processing.

  FIG. 12 is an example of a UI configuration according to each of the above embodiments, and is a diagram illustrating a screen displayed by the display unit 105.

  The image selection button 1201 receives an instruction to select an image to which a panning effect is desired. When the image selection button 1201 is touched or selected by a cursor or the like, the CPU 103 receives an instruction from the image selection button 1201 and scrolls or displays a list of target image candidates or target image candidate file names in the recording medium 107. . The user selects an image to be processed from the displayed images.

  The mode selection button 1202 accepts an instruction for selecting whether to edit an image manually or automatically. When an image is manually edited, the user himself selects the target image or image group, selects and adjusts the effect amount of panning. If automatic editing is selected, the flow amount is automatically set from the target image or image group by image analysis, and processing is performed. In addition, the selection of the target image may be automatically determined by referring to the header information of the image, for example, targeting the last group of continuously shot images.

  The effect selection button 1203 receives an instruction to select how much the background is to be played and the effect amount of the panning shot. In each of the embodiments described above, the background flow amount as the effect amount is designated by either the corresponding shutter speed, the effect small, medium, large, or the number of pixels input. However, the UI for setting the flow amount is not limited to this. For example, one of the images to be combined is displayed on the display medium by the display unit 105, the magnitude of the effect amount is displayed as a bar icon, The magnitude of the effect amount may be set by moving the index by a touch operation. In addition, by dragging in a predetermined direction while touching one of the background parts of the displayed image, or by touching at least two points that define the start and end points of the sink, the length indicated in the predetermined direction You may make it produce | generate the synthetic | combination image which gave the flow amount only by the part. The touch operation is not limited to the above as long as the flow amount can be defined.

  The result image display unit 1204 can display a plurality of composite images generated under the respective conditions. Setting values (such as a flow amount) for editing each composite image are displayed in an area 1205. In FIG. 12, the effect amount is listed as small, medium, or large, but the shutter speed may be set in three stages and displayed as a list. Further, a list of images in which the pattern of which images are to be combined among the image groups to be combined may be displayed.

  A save button 1206 receives an instruction to record the image displayed on the result image display unit 1204 on a recording medium.

  The setting display unit 1207 displays the current status such as the current editing mode and the effect amount set for the recorded image.

  The initial image display unit 1208 displays one of the selected image or image group as an initial image. The image displayed as the initial image may be any of the group of images. For example, the first image in time series or the image in the middle in time series that can be used as a reference for alignment or the like is displayed. The displayed image may be changed within the image selected as the image group by touching or selecting the displayed image with a cursor.

  The image information display unit 1209 displays image information of one of the initial image, the entire image group, and the stored composite image. For example, immediately after the result image is saved by the save button 1206, one large result image is displayed on the result image display unit 1204, and the file name and focal length of the result image are displayed on the image information display unit 1209. The flow rate and the shutter speed corresponding to the flow rate are displayed.

  As described above, in the present embodiment, the unblurred image is aligned and combined, and the blurring process is performed to blur the background. By doing so, it is possible to provide a panning-like composite image having the same effect as a photographed image at a shutter speed that is difficult to shoot in general panning. Further, when combining a plurality of images, a more effective panning-like composite image can be provided by performing a blurring process on the background according to the amount of movement of the background relative to the main subject. In addition, because the user can shoot at the amount of sinking that the background wants to flow regardless of the speed of the main subject, it is appropriate even without being aware of the appropriate shutter speed, which is the most important setting item in panning. It is possible to generate a composite image in the form of a panning shot.

(Other embodiments)
The object of the present invention can also be achieved as follows. That is, a storage medium in which a program code of software in which a procedure for realizing the functions of the above-described embodiments is described is recorded is supplied to the system or apparatus. The computer (or CPU, MPU, etc.) of the system or apparatus reads out and executes the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium and program storing the program code constitute the present invention.

  Examples of the storage medium for supplying the program code include a flexible disk, a hard disk, an optical disk, and a magneto-optical disk. Further, a CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD-R, magnetic tape, nonvolatile memory card, ROM, or the like can also be used.

  Further, by making the program code read by the computer executable, the functions of the above-described embodiments are realized. Furthermore, when the OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, the functions of the above-described embodiments are realized by the processing. Is also included.

  Furthermore, the following cases are also included. First, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

  In addition, the present invention is not limited to devices such as digital cameras, but includes built-in or external connection of imaging devices such as mobile phones, personal computers (laptop type, desktop type, tablet type, etc.), game machines, etc. It can be applied to any device. Therefore, the “imaging device” in this specification is intended to include any electronic device having an imaging function.

DESCRIPTION OF SYMBOLS 100 Image pick-up device 101 Optical system 102 Image pick-up element 103 Central processing unit (CPU)
104 Primary storage device 105 Angular velocity sensor 106 Image processing device 107 Recording medium 108 Secondary storage device 109 Display unit 110 Operation unit

Claims (10)

A specifying unit for specifying a main subject region and a background region different from the main subject region for a plurality of images captured by the imaging unit;
Aligning the main subject areas of the plurality of images;
A combining unit that generates a combined image obtained by applying a predetermined blurring process by applying a low-pass filter to the background region;
Detecting means for detecting the amount of movement of the background area between the plurality of images based on the image of the background area or information on shake of the imaging means for the plurality of images;
Have a, and a control means for controlling the amount of blur in the blurring process on the basis of the amount of movement of the background region between the plurality of images detected by the detection unit,
Said control means, said controls to correspond to the amount of blurring the number of taps of the low-pass filter, image processing, wherein the control child in accordance with coefficients in the taps of said low-pass filter in the region of the synthesized image apparatus. Setting means for setting a flow amount of the background region in the composite image;
The image processing apparatus according to claim 1, wherein the combining unit controls the number of images to be combined based on the flow amount set by the setting unit. The flow amount is information corresponding to the shutter speed corresponding to the composite image,
3. The image processing according to claim 2, wherein the synthesizing unit controls the number of images to be synthesized so that a total shutter speed of images used for synthesis becomes a shutter speed set by the setting unit. apparatus. The amount of flow is information corresponding to the flow width of the background region in the composite image,
The image processing apparatus according to claim 2, wherein the synthesizing unit controls the number of images to be synthesized based on the movement amount of the background region and the flow amount. Said detecting means, said calculating a motion vector between a plurality of images, according to any one of claims 1 to 4, characterized in that to detect the moving amount of the background area based on the movement vector Image processing device. The detecting device, an image processing apparatus according to any one of claims 1 to 4, characterized in that to detect the moving amount of the background region on the basis of the shake information of the image pickup means. The specifying unit may calculate a motion vector between the plurality of images, the image processing according to any one of claims 1 to 6, wherein the identifying the main subject area based on the movement vector apparatus. The specifying unit, an image processing apparatus according to any one of claims 1 to 6, wherein the identifying the main subject area based on the shake information of the image pickup means. Display means for displaying the plurality of images on a display medium;
Detecting means for detecting a touch operation on the display medium,
Said control means detects the touch operation on the display medium in the displayed image, any one of claims 2 to 8, characterized in that for setting the flow amount of the background region in the composite image An image processing apparatus according to 1. A specifying step for specifying a main subject region and a background region different from the main subject region for a plurality of images picked up by the image pickup means;
A step of aligning the main subject areas of the plurality of images, and applying a low-pass filter to the background area to generate a composite image with a predetermined blurring process;
Detecting the amount of movement of the background region between the plurality of images based on the image of the background region or information on shake of the imaging means for the plurality of images;
Have a, and a control step of controlling the amount of blur in the blurring process on the basis of the amount of movement of the background region between the plurality of images detected by the detecting step,
In the control step, the controls so as to correspond to the amount of blurring the number of taps of the low-pass filter, image processing, wherein the control child in accordance with coefficients in the taps of said low-pass filter in the region of the synthesized image Method.

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