Blur evaluation device, blur evaluation method, method for manufacturing photographing means, and program

Abstract

To provide a shake evaluation device capable of accurately evaluating a shake of imaging means.SOLUTION: A shake evaluation device (100) for evaluating a shake of imaging means (11) comprises: scanning means (14b) which scans a subject (14) in a first direction; vibration means (12) which vibrates the imaging means which images the subject being scanned by the scanning means, in a second direction different from the first direction; and measurement means (15) which, on the basis of, trajectory variation related with the second direction in an image obtained by imaging by the imaging means, evaluates a shake amount of the image.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a blur evaluation device that evaluates blur of imaging means.

Background Art

[0002] Patent Document 1 discloses a measuring device that measures the effect of a shake correction function of a camera to be measured by fixing the camera to be measured (imaging means) to a vibration table of a vibration device, photographing a chart with the camera to be measured, and analyzing the resulting image with a computer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the measuring device disclosed in Patent Document 1 cannot accurately evaluate the blur of the imaging means.

[0005] Therefore, an object of the present invention is to provide a blur evaluation device, a blur evaluation method, a manufacturing method of imaging means, and a program capable of accurately evaluating the blur of photographing means.

Means for Solving the Problems

[0006] A blur evaluation device according to one aspect of the present invention is With a vibration-proof function a blur evaluation device that evaluates blur of imaging means, including scanning means for scanning a subject in a first direction, and the subject being scanned by the scanning means In the state where the vibration-proof function is turned on vibration means for vibrating the imaging means for photographing in a second direction different from the first direction, and based on a locus change related to the second direction in an image photographed by the imaging means, the blur amount of the image is MeasurementIt has a measurement means to be performed.

[0007] Other objects and features of the present invention will be described in the following embodiments.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a shake evaluation device, a shake evaluation method, a manufacturing method of a photographing means, and a program capable of highly accurately evaluating the shake of the photographing means.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] (First Embodiment) First, the first embodiment of the present invention will be described. FIG. 1 is a schematic diagram of a blur evaluation apparatus 100 that executes a hand blur measurement method (blur evaluation method) in the present embodiment. FIG. 1(a) shows a side view of the blur evaluation apparatus 100, FIG. 1(b) shows a top view, and FIG. 1(c) shows a perspective view. 11 is a measurement camera (imaging means), which is held by the photographer. The measurement camera 11 faces a chart (subject) 14. The chart image captured by the measurement camera 11 is input to a locus change measurement means (measurement means) 15. The locus change measurement means 15 detects the captured chart image locus and measures the degree of deterioration of the captured image due to the hand blur of the photographer.

[0012] Here, there are two features in the present embodiment. First, the chart 14 can be scanned in the direction of arrow 14cP in FIG. 1(b) by an actuator (scanning means) 14b, and the chart 14 is scanned in the direction of arrow 14cP while the measurement camera 11 is capturing the chart 14. Second, a point object 14a is provided on the chart 14, and the locus change measurement means 15 obtains the centroid at each scanning position of the point image captured by the measurement camera 11. The above will be described in detail below.

[0013] Figure 2 is an image (trajectory image) captured by the measurement camera 11 in a state where hand shake has occurred. In Figure 2, in the image 21, the trajectory of the dot image 22 due to the point object 14a being scanned during imaging is reflected. 22a is the trajectory of the center of gravity at each scanning position of the dot image. The trajectory change measuring means 15 obtains the horizontal projection of the image 22 and the center of gravity of the luminance at each horizontal position.

[0014] Figure 3 is an extraction graph of the center-of-gravity trajectory of the binarized dot image after obtaining the center of gravity of the image in Figure 2. In Figure 3, the horizontal axis represents the horizontal pixels of the imaging element provided in the measurement camera 11, and the vertical axis represents the vertical pixels respectively. The waveform 31 is a trajectory waveform connecting the center-of-gravity positions of the vertical pixels of the dot image at each horizontal pixel. By measuring the vertical amplitude 32 of the waveform 31, the vertical shake of the measurement camera 11 can be obtained.

[0015] Figure 4 is a perspective view of the blur evaluation device 100. As shown in Figure 4, the chart 14 is also scanable in the direction of the arrow 14cY, and the chart 14 is scanned in the direction of the arrow 14cY while the measurement camera 11 is imaging the chart 14. The trajectory image at this time is shown in Figure 5. In Figure 5, in the image 51, the trajectory of the dot image 52 due to the point object 14a being scanned during imaging is reflected. 52a is the trajectory of the center of gravity at each scanning position of the dot image. The trajectory change measuring means 15 obtains the vertical projection of the image 22 and the center of gravity of the luminance at each vertical position. Figure 6 is an extraction graph of the center-of-gravity trajectory of the binarized dot image after obtaining the center of gravity of the image in Figure 5. In Figure 6, the horizontal axis represents the horizontal pixels of the imaging element provided in the measurement camera 11, and the vertical axis represents the vertical pixels respectively. The waveform 61 is a trajectory waveform connecting the horizontal-pixel center-of-gravity positions of the dot image at each horizontal pixel. By measuring the horizontal amplitude 62 of the waveform 61, the horizontal shake of the measurement camera 11 can be obtained.

[0016] FIG. 7 is a side view of the shake evaluation apparatus 100, and shows an example in which the measurement camera 11 is fixed to the vibration table (vibration means) 12 instead of being held by the photographer. The vibration table 12 vibrates the measurement camera 11 around the arrow 12aP and around the arrow 12aY perpendicular to the arrow 12aP based on the vibration waveform data 13. The chart 14 is scanned in the directions of the arrow 14cP and the arrow 14cY orthogonal to the arrow 14cP. The measurement camera 11 facing the chart 14 photographs the scanned chart 14 photographed while being vibrated by the vibration table 12. The chart image of the measurement camera 11 is input to the locus change measurement means 15, and the locus change measurement means 15 detects the photographed chart image locus and measures the degree of degradation of the photographed image due to shake when vibrated by the vibration waveform 13.

[0017] In the above example, the photographing of the measurement camera 11 by the vibration in the direction of the arrow 12aP and the scanning in the direction of the arrow 14cP and the photographing of the measurement camera 11 by the vibration in the direction of the arrow 12aY and the scanning in the direction of the arrow 14cY are shifted in time. For this reason, the image 21 in FIG. 2 and the image 51 in FIG. 5 are different images. Then, the shake of the measurement camera due to the vibration in the direction of the arrow 12aP and the shake of the measurement camera due to the vibration in the direction of the arrow 12aY are obtained from the locus waveforms of the respective images 21 and 51. Here, the measurement camera 11 is vibrated in a direction (second direction) different from the directions of the arrows 14cP and 14cY (first direction) which are the scanning directions of the chart 14. For this reason, the photographing of the measurement camera 11 by the vibration in the direction of the arrow 12aP and the scanning in the direction of the arrow 14cP and the photographing of the measurement camera 11 by the vibration in the direction of the arrow 12aY and the scanning in the direction of the arrow 14cY are performed simultaneously. As a result, as shown in the image 81 in FIG. 8 which is a locus image, the locus 82P and 82Y of the dot images are recorded in a single image. Then, the locus waveforms shown in FIGS. 3 and 6 can be created from the two images obtained by trimming the image 81 with the frames 83P and 83Y, and the amount of shake for each of the vibration directions 12aP and 12aY can be obtained.

[0018] Here, with reference to FIG. 9, a method (shake calculation method) for obtaining the amount of shake for each exposure time of the measurement camera 11 will be described. FIG. 9 is a graph of the shake calculation method. In FIG. 9, the horizontal axis represents the horizontal pixels and the vertical axis represents the vertical pixels, respectively.

[0019] Figure 9(a) is a graph showing a blur calculation method in which the locus waveform 31 in FIG. 3 is divided by a plurality of calculation regions of the exposure times 91a to 91d of the measurement camera 11. Here, a method of also showing the exposure time in FIG. 9(a) will be described. The value obtained by multiplying the imaging magnification of the measurement camera 11 by the constant scanning speed of the chart 14 becomes the image plane speed on the imaging element of the measurement camera 11. Dividing this image plane speed by the pixel size of the imaging element gives the number of moving pixels per unit time (pixel speed). Therefore, when the pixel speed is multiplied by the exposure time (for example, 1 / 60 second), the number of moving pixels per exposure time can be obtained, so the horizontal axis pixel number in FIG. 9(a) can be made to correspond to the exposure time.

[0020] FIGS. 9(b) and 9(c) are enlarged views of the locus waveform 31 divided by the calculation region 91a surrounded by the circle 92 in FIG. 9(a). In FIG. 9(a), a plurality of calculation regions from 91a (for example, 1 / 60 second) to 91d (for example, 1 / 8 second) are divided from the calculation start point 91. The amount of blur is obtained by the number of pixels in the interval 93 between the maximum and minimum values of the locus waveform 31 at each exposure time (for example, the calculation region 91a), as shown in FIG. 9(b). Alternatively, as shown in FIG. 9(c), the areas S1 and S2 where the locus waveform divides the rectangle 95 surrounded by the maximum and minimum values of the locus waveform and the calculation region 91a are obtained, and the smaller of the areas S1 and S2 is divided by the exposure time 91a to obtain the amount of blur. In FIG. 9(b), there is little blur and little image degradation between the calculation start point 91 and the interval 94, and then the blur increases in a short time. In such a case of blur, the amount of blur 93 does not correctly represent the image degradation due to blur. On the other hand, with the method described in FIG. 9(c), the blur reflecting the curve of the blur during the exposure time can be obtained.

[0021] In FIG. 9(a), the amount of blur between the divided calculation regions 91a to 91d can be obtained at once. In the prior art, the measurement camera was photographed for each exposure time, but according to the method of this embodiment, such an operation becomes unnecessary. Further, the calculation start point 96 of the broken line obtained by shifting the solid line calculation start point 91 set in FIG. 9(a) one pixel to the right is used to set the calculation regions 96a to 96d of the broken line (FIG. 9(d)), and the amount of blur is obtained for each set exposure time. By averaging a large amount of blur amount data obtained by shifting pixels in order in the section where the locus waveform 31 is continuous in the measurement of FIG. 9(d) for each calculation region, the amount of blur can be stably obtained. In the prior art, a large number of images were acquired using the measurement camera 11 at each exposure time, and the amount of blur was obtained by processing the obtained images. However, according to this embodiment, such an operation also becomes unnecessary.

[0022] In the prior art, a method for obtaining the amount of blur from the amount of blur in the photographed image of the measurement camera has been disclosed. However, it is difficult to accurately separate the blur of the image peculiar to the measurement camera 11 when not vibrating and the blur of the image due to the blur when vibrating by such a method. On the other hand, as described with reference to FIG. 9, in this embodiment, an accurate amount of blur can be directly obtained from the centroid locus waveform of the point image.

[0023] FIG. 10 is a flowchart of a simple measurement method for photographing the chart 14 by the measurement camera 11. First, in step s1001, the exposure time of the measurement camera 11 is set. When measuring the amount of blur from 1 / 60 second to 2 seconds of the exposure time, the exposure time is set to 4 seconds, which is twice the longest exposure time of 2 seconds. The brightness of the point object 14a on the chart 14 is adjusted by adjusting the illumination so as to achieve proper exposure with the set exposure time, aperture value, and ISO sensitivity, or by attaching an ND filter to the imaging system of the measurement camera 11.

[0024] Subsequently, in step S1002, the anti-vibration function of the measurement camera 11 is turned on. As will be described later, in this embodiment, it is not necessary to measure the amount of blur with the anti-vibration function off. Subsequently, in step S1003, the vibration table 12 is operated to start vibrating the measurement camera 11 in the 12aP and 12aY directions. Subsequently, in step S1004, the chart 14 is scanned in the 14cP and 14cY directions. Subsequently, in step S1005, shooting is started with the measurement camera 11 during vibration. Subsequently, in step S1006, step S1006 is looped and waited until shooting, for example, for 4 seconds is completed. Then, this flow ends after shooting is completed. As a result, the image shown in FIG. 8 is obtained.

[0025] FIG. 11 is a flowchart of a blur calculation method for calculating the blur of the measurement camera 11 from the image obtained by the measurement flow of FIG. 10. Each step in FIG. 11 is mainly executed by the locus change measurement means 15.

[0026] First, in step S1101, the image 81 in FIG. 8 is captured. Subsequently, in step S1102, the image 81 is trimmed with the frames 83P and 83Y, respectively. Subsequently, in step S1103, the centroid positions of the point images in the images of the frames 83P and 83Y are obtained, and the locus waveforms 31 and 61 shown in FIGS. 3 and 6 are extracted to obtain a locus waveform P and a locus waveform Y.

[0027] Subsequently, in step S1104, a blur amount calculation start point 91 shown in FIG. 9(a) is set. Subsequently, in step S1105, a blur amount calculation region is set. Specifically, as shown in FIG. 9(a) for the locus waveforms P and Y, an interval of a first calculation region 91a is set. Subsequently, in step S1106, the blur amounts of the locus waveforms P and Y in the calculation region set using the method shown in FIG. 9(c) are obtained to obtain a blur amount P and a blur amount Y. Subsequently, in step S1107, the blur amounts P and Y are square-averaged to calculate and record a blur amount PY.

[0028] Subsequently, in step S1108, it is determined whether or not the calculation of the amount of blur in the set calculation area has been completed. If the calculation of the amount of blur has not been completed, the process returns to step S1105, the next section (for example, the second calculation area 91b in FIG. 9(a)) is set, and the amount of blur PY in that calculation area is recorded in step S1107. When the amounts of blur PY in all the calculation areas (exposure times 91a to 91d) in FIG. 9(a) are recorded, the process proceeds to step S1109.

[0029] In step S1109, the next calculation start point is set. That is, the calculation start point 96 in FIG. 9(d) is set. Subsequently, in step S1110, it is determined whether or not the amounts of blur PY in each calculation area at the set calculation start point have all been calculated. If there is an uncalculated calculation start point, the process returns to step S1105 and continues the calculation of the amount of blur. When the calculation of the amounts of blur PY in each calculation area at all the calculation start points is completed, the process proceeds to step S1111. In step S1111, the amounts of blur PY at the recorded calculation start points are averaged for each calculation area to obtain the average amount of blur PY.

[0030] FIG. 12 is an anti-vibration performance evaluation graph, showing the average amount of blur PY obtained by the above blur calculation. In FIG. 12, the horizontal axis represents the exposure time, and for example, the calculation areas of the exposure times 91a to 91d in FIG. 9(a) are arranged in order corresponding to the exposure time. The horizontal axis indicates that the exposure time increases as going to the right. The vertical axis represents the average amount of blur PY. The solid curve 1201 is the average amount of blur PY curve obtained by the flow in FIG. 11 and is the remaining amount of blur correction when the anti-vibration function of the measurement camera 11 is turned on. The dashed curve 1202 is the amount of blur when the anti-vibration function is turned off. The curve 1202 is not the result obtained from the measurement camera 11 but a theoretical curve plotted with theoretically obtained numerical values. The reason why the theoretical curve can be used will be explained below.

[0031] As described above, the amount of blur is obtained by using the centroid locus waveform of the point image. Therefore, the optical performance and image processing specific to each camera model do not affect the amount of blur, and only the anti-shake performance can be evaluated. Thus, when the anti-shake function is turned off, the amount of blur based on the vibration waveform data 13 of the vibration table 12 can be obtained for any camera, so it is not necessary to measure the amount of blur with the anti-shake function off for each camera. The theoretical curve 1202 is obtained as follows in (1) to (4) as in steps s374 and later in FIG. 11. (1) By multiplying the vibration waveform data 13, which is the angular data around 12aP and 12aY in FIG. 7, by the focal length of the measurement camera, locus waveforms 1301P and 1301Y indicating the amount of blur on the image plane are obtained. In the graph of the blur calculation method with the anti-shake function off in FIG. 13, only the locus waveform 1301P is shown. (2) Set the calculation start point 1302 and obtain the amount of blur P and the amount of blur Y in each calculation area 1302a to 1302d at the calculation start point 1302 from the respective locus waveforms 1301P and 1301Y. (3) Square-average the amount of blur P and the amount of blur Y to obtain the amount of blur PY. (4) Shift the calculation start point and obtain the amount of blur in each calculation area 1302a to 1302d from the respective locus waveforms 1301P and 1301Y. (5) Average the amount of blur PY at each calculation start point over each calculation area to obtain the average amount of blur PY.

[0032] Read from the graph the exposure times A and B, which are the intersections of the theoretical curve 1202 in FIG. 12 and the average amount of blur PY curve 1201 with the anti-shake function on, with the predetermined allowable amount of blur threshold 1203 obtained by the above calculations. Since the larger the difference 1204 between the exposure time A and the exposure time B indicates higher anti-shake performance, the anti-shake performance can be evaluated by the difference 1204 between the exposure time A and the exposure time B.

[0033] Here, a function for improving the measurement accuracy will be described. If the positional relationship between the trajectories 82P and 82Y of the dot-like images shown in FIG. 8 and the positions of the frames 83P and 83Y is misaligned, accurate trimming of the dot-like images cannot be performed. Also, the shape of the trajectory of the dot-like image may change due to optical distortion depending on whether the trajectories 82P and 82Y of the dot-like images are projected onto the center of the image 81 or onto the periphery of the image 81. Therefore, a function is provided to project the trajectories 82P and 82Y of the dot-like images onto always the same position in the image 81.

[0034] FIG. 14 is an explanatory diagram of subject scanning control. In FIG. 14(a), a release signal, which is a shooting start signal of the measurement camera 11, is input to a scanning instruction means 1401, which is a measurement synchronization means. The scanning instruction means 1401 receives the release signal and gives a chart 14 scanning instruction to the actuator 14b. By aligning the timings of shooting start and chart scanning in this way, the positional relationship of the trajectories 82P and 82Y of the dot-like images in the image 81 is always kept constant. Note that since it is not a constant-speed scan for a while after the start of chart 14 scanning, the correct exposure time cannot be set in that section. Therefore, a calculation start point 91 shown in FIG. 9(d) is set within the constant-speed scan section so that the amount of blur is not calculated for the trajectory waveform 31a during scanning acceleration.

[0035] In FIG. 14(b), a position detection means 1402 for detecting the scanning position of the chart 14 is provided. The position detection means 1402 is a measurement synchronization means and sends the position where the chart 14 becomes a constant-speed scan to the measurement camera 11. The measurement camera 11 performs shooting at the timing output from the position detection means 1402. Even with such a configuration, the positional relationship of the trajectories 82P and 82Y of the dot-like images in the image 81 is always kept constant. And since the chart during scanning acceleration is not photographed, the calculation start point 91 can be set at the start point of the trajectory waveform 31, and the calculated amount of blur can be increased. By obtaining the amount of blur using the trajectory waveform obtained from the center of gravity in the trajectory of the dot-like image in this way, the camera blur can be evaluated more accurately and the measurement time can be significantly shortened.

[0036] As described above, the blur evaluation apparatus 100 according to the present embodiment includes a scanning unit (actuator 14b) that scans a subject (chart 14) which is a point object 14a, and an imaging unit (measurement camera 11) that captures an image of the subject during scanning. The blur evaluation apparatus 100 also includes a vibration unit (vibration table 12) that vibrates the imaging unit in a direction different from the scanning direction (first direction) of the subject (second direction, i.e., vibration direction). The blur evaluation apparatus 100 further includes a locus change measurement unit 15 that measures the blur of the imaging unit based on a locus change (loci 22, 52 of point images) related to the vibration direction of the subject image captured by the imaging unit. Then, the blur evaluation apparatus 100 evaluates the blur of the imaging unit based on the output of the locus change measurement unit 15. Specifically, the locus change measurement unit 15 obtains locus waveforms 31, 61 from the centroid locus of the point images of the subject image (step s1103 in FIG. 11) and determines the amount of blur from the obtained locus waveforms.

[0037] Further, the locus change measurement unit 15 divides the locus waveforms 31, 61 into a plurality of calculation regions (from 91a to 91d) and determines the amount of blur for each of the plurality of calculation regions. Also, the locus change measurement unit 15 determines the intervals of the plurality of calculation regions based on the exposure time of the imaging unit (measurement camera 11). Further, the locus change measurement unit 15 moves the plurality of calculation regions (shifts the calculation start point 91) and determines the amount of blur in each movement region. Furthermore, the blur evaluation apparatus 100 includes a measurement synchronization unit (scanning instruction unit 1401, position detection unit 1402) that synchronizes the imaging of the imaging unit (measurement camera 11) with the scanning of the scanning unit (actuator 14b). The measurement synchronization unit (scanning instruction unit 1401) controls the scanning unit (actuator 14b) based on the imaging timing of the imaging unit (measurement camera 11). The measurement synchronization unit (position detection unit 1402) controls the imaging of the imaging unit (measurement camera 11) in synchronization with the position of the subject (chart 14) scanned by the scanning unit (actuator 14b).

[0038] (Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 15 is a side view of a shake evaluation device 100a that executes a hand shake amount measurement method in this embodiment. The shake evaluation device 100a is different from the shake evaluation device 100 of the first embodiment having a point object 14a in that it has a collimated light source 1501a and a point light source 1501b. The chart 14 is rotationally scanned in the directions of arrows 1502P and 1502Y around an axis 1503 that is the principal point position or aperture position of the measurement camera 11.

[0039] First, the reason for using the collimated light source 1501a and the point light source 1501b instead of the chart 14a will be explained. FIG. 16 is an explanatory diagram of the collimated light source. FIG. 16(a) is a cross-sectional view of the collimated light source 1502a, which is composed of a lens barrel 1601, a lens 1602 fixed to the lens barrel 1601, and a light source 1603 disposed at the focal length position of the lens 1602. Since the light source is provided at the focal length position of the lens, the light beam emitted from the light source becomes parallel light (collimated light) through the lens 1602. Since the parallel light is a subject light source at an infinite position, the photographing magnification of the measurement camera 11 becomes extremely small.

[0040] The shake applied to the camera includes a rotational shake 1701 and a shift shake 1702 shown in FIG. 17. The shift of the imaging surface due to the shift shake 1702 can be ignored when the photographing magnification of the measurement camera 11 is small. Therefore, by using the collimated light source 1502a, only the shake amount due to the rotational shake can be measured. As shown in FIG. 16(b), the point light source 1501b has a configuration in which the lens 1602 in FIG. 16(a) is removed. Therefore, the shake amount in which the shift shake and the rotational shake corresponding to the photographing magnification of the measurement camera 11 with respect to the point light source 1502b are mixed is measured. Therefore, only the shake amount due to the shift shake can be obtained from the difference between the locus waveform obtained from the collimated light source 1502a and the locus waveform obtained from the point light source 1502b. In this way, the shake amount due to the rotational shake and the shake amount due to the shift shake can be separated, and the anti-shake performance for each shake can be evaluated.

[0041] Next, the reason for rotating and scanning the chart 14 around the axis 1503 in the directions of the arrows 1502P and 1502Y, which is different from the first embodiment, will be explained. Since the collimated light source 1502a is a light source of a subject at an infinite position, even if it is linearly scanned like in the first embodiment, the position of the light source does not change on the imaging surface in the measurement camera 11, and a trajectory waveform cannot be obtained. When the collimated light source 1502a is rotationally scanned, a trajectory waveform can be obtained. However, when rotationally scanning around the position 1801 of the collimated light source, as shown in Fig. 18(a), the emitted light source causes optical astigmatism, and a trajectory waveform of sufficient length cannot be obtained on the image plane 11a. On the other hand, as shown in Fig. 18(b), when the collimated light source 1502a is rotationally scanned around the axis 1503, the influence of astigmatism can be reduced, and a trajectory waveform of sufficient length can be obtained on the image plane 11a. Since the point light source 1502b can obtain a trajectory waveform of sufficient length on the image plane both in linear scanning and rotational scanning, it may be rotationally scanned integrally with the collimated light source 1502a.

[0042] In this embodiment, by linearly scanning and rotationally scanning the collimated light source, rotational scanning around the virtual axis 1503 is performed. Fig. 19 is an explanatory diagram of subject scanning control, which simply shows its configuration. The linear scanning actuator, which is the linear scanning means 1902, scans the linear scanning table 1901 in the direction of the arrow 1901a. The rotational scanning table 1903 provided on the linear scanning table 1901 is rotationally scanned around the axis 1903b in the direction of the arrow 1903a on the linear scanning table 1901 by the rotational scanning actuator, which is the rotational scanning means 1904. By the cooperation of linear scanning and rotational scanning, the collimated light source 1502a is scanned to 1502a' shown by the dotted line. This is approximately equivalent to rotationally scanning the collimated light source 1502a around the virtual axis 1503 (arrow 1905). Exactly, the distance between the collimated light source 1502a and the measurement camera 11 slightly changes (gap 1906) with the rotational scanning, but due to the infinite light source, the change in distance is not a problem.

[0043] The position detection means 1402 continuously detects the position of the linear scanning table 1901, and controls the imaging timing of the measurement camera 11 in the same manner as described in FIG. 14. Further, based on the position detection output of the position detection means 1402, a rotation control means 1904a is provided for the rotation scanning means 1904 to control the rotation angle of the rotation scanning table. In this way, by adjusting the relationship between the output of the position detection means 1402 and the rotation scanning amount of the rotation scanning means 1904 with the rotation control means 1904a, it is possible to change the position of the virtual rotation axis 1503. Also, the position of the linear scanning table 1901 in the direction of the arrow 1907 can be changed. By performing the position adjustment of the rotation control means 1904a and the arrow 1907, the collimated light source 1502a can be optimally rotationally scanned according to the optical characteristics of the measurement camera 11. For example, with a wide-angle lens having a short focal length, the rotation radius of the rotational scan can be reduced, and with a telephoto lens having a long focal length, the rotation radius of the rotational scan can be increased.

[0044] FIG. 20 is a subject layout diagram when the chart 14 in FIG. 15 is viewed from the measurement camera 11 side. On the chart 14, collimated light sources 1502aP, 1502aY and point light sources 1502bP, 1502bY are provided. The collimated light source 1502aP and the point light source 1502bP are integrally rotationally scanned in the direction of the arrow 2001P (the arrow becomes a straight line in the direction of FIG. 20). Also, the collimated light source 1502aY and the point light source 1502bY are integrally rotationally scanned in the direction of the arrow 2001Y (the arrow becomes a straight line in the direction of FIG. 20).

[0045] FIG. 21 is an image of the point image trajectories of the collimated light source and the point light source in FIG. 20 taken by the measurement camera 11. In the image 2101, the point image trajectory of the collimated light source 1502aP is 2102aP, the point image trajectory of the point light source 1502bP is 2102bP, the point image trajectory of the collimated light source 1502aY is 2102aY, and the point image trajectory of the point light source 1502bY is 2102bY. Then, each point image trajectory can be trimmed in the same manner as in FIG. 8, and the average blur amount PY can be obtained in the same manner as in the first embodiment.

[0046] FIG. 22 is, similar to FIG. 12, the anti-vibration performance evaluation diagram obtained in this embodiment, showing the average blur amount PY. The solid curve 2201a is the average blur amount PY curve obtained by the collimated light source 1502a, and the solid curve 2201b is the average blur amount PY curve obtained by the point light source 1502b. Then, the exposure times A, B, and C, which are the intersections of the theoretical curve 1202 when the anti-vibration function is off and the respective predetermined allowable blur amount thresholds 1203 of the average blur amount PY curves 2201a and 2201b when the anti-vibration function is on, are read from the graph. The difference between the exposure time A and the exposure time B is the evaluation of the anti-vibration performance without including the shift blur, and the difference between the exposure time A and the exposure time C is the evaluation of the anti-vibration performance including the shift blur.

[0047] In this embodiment, the blur evaluation (anti-vibration performance evaluation) of the camera has been described by taking an example of vibrating the measurement camera 11 using the vibration table 12. However, it is not limited to the vibration table 12. The photographer may hold the measurement camera 11 and evaluate the anti-vibration performance with the camera shake of the photographer himself / herself. In this case, the theoretical curve 1202 may be used for the off state of the anti-vibration function, or the photographer may create a measurement curve with the anti-vibration function of the measurement camera 11 turned off. In this way, by obtaining the blur amount using the trajectory waveform obtained from the centroid locus of the point image, the camera blur can be evaluated more accurately and the measurement time can be significantly shortened. Furthermore, by using a collimated light source as the point object, the blur amount caused only by the angular blur can be accurately obtained.

[0048] As described above, the shake evaluation device 100a of the present embodiment includes a scanning unit (actuator 14b) that scans a subject (chart 14) which is a point object 14a, and an imaging unit (measurement camera 11) that captures the subject during scanning. The shake evaluation device 100a also includes a vibration unit (vibration table 12) that vibrates the imaging unit in a direction different from the scanning direction of the subject. The shake evaluation device 100a further includes a locus change measurement unit 15 that measures the shake of the imaging unit based on the locus change (point image trajectories 2102aP, 2102bP, 2102aY, 2102bY) of the subject image captured by the imaging unit. Then, the shake evaluation device 100a evaluates the shake of the imaging unit based on the output of the locus change measurement unit 15. Specifically, the subject 14 is a collimated light source, and the locus change measurement unit 15 obtains the amount of shake from the locus waveform obtained from the centroid locus of the subject image. Also, the scanning units (linear scanning unit 1902, rotational scanning unit 1904) rotate and scan the subject (chart 14) with the imaging unit as the central axis 1503. The shake evaluation device 100a also has a rotation control unit 1904a that changes the rotation radius of the scanning unit.

[0049] (Third Embodiment) Next, a third embodiment of the present invention will be described. FIG. 23 is a perspective view of the shake evaluation device 100b in the present embodiment. As described with reference to FIG. 7, in the first embodiment, the chart 14 has a point object scanned in the direction of arrow 14cP and a point object scanned in the direction of arrow 14cY, and the amount of shake was obtained from the point image locus of the obtained image 81. On the other hand, in the present embodiment shown in FIG. 23, the point object 2301 is scanned in the direction of arrow 2302 which is inclined -45 degrees from the shake direction generated by the vibration directions 12aP, 12aY of the vibration table 12. Also, the measurement camera 11 is subjected to combined vibration around the combined vibration axis (synthetic vibration axis) 12aPY by being vibrated with the same vibration waveform data in the directions of arrows 12aP, 12aY by the vibration table 12.

[0050] In this way, with the combination of making the scanning direction orthogonal to the synthetic vibration axis, similar to FIG. 3, the locus image 2401 in FIG. 24 is obtained, and the locus waveform 2501a shown in FIG. 25(a) is obtained from the locus image. Further, the locus waveform 2501a is subjected to a 45-degree coordinate transformation to obtain the locus waveform 2501b shown in FIG. 25(b). From the obtained locus waveform 2501b, the amount of blur is obtained by the method described in FIG. 9. However, since the blurs in the vibration directions 12aP and 12aY of the vibration table 12 are already mixed as the vibration direction (vibration axis 12aPY) in the locus waveform 2501b, it is not necessary to perform the root mean square of the blurs in the two directions as in the first and second embodiments.

[0051] FIG. 26 is a flowchart of a blur calculation method in which the locus change measuring means 15 calculates the blur of the measurement camera 11 from the image 2401 in the present embodiment. FIG. 26 shows a flow in which the blur calculation in two directions and their root mean square in FIG. 11 are omitted. In this way, by scanning the point object in a direction different from the two-directional blur generated in the measurement camera 11 due to the vibration of the vibration table 12, the arithmetic processing can be simplified.

[0052] As described above, the blur evaluation apparatus 100b of the present embodiment includes a scanning means (actuator 14b) that scans a subject (chart 14) that is a point object 14a, and a photographing means (measurement camera 11) that photographs the subject during scanning. The blur evaluation apparatus 100b also includes a vibration means (vibration table 12) that vibrates the photographing means, and a locus change measuring means 15 that measures the blur of the camera based on the locus change (locus 2302 of the point image) of the subject image photographed by the photographing means. Then, the blur evaluation apparatus 100b evaluates the blur of the photographing means based on the output of the locus change measuring means 15. The scanning means (actuator 14b) scans the subject (chart 14) in a direction different from the plurality of vibration directions (12aP, 12aY) of the vibration means 12. Specifically, the scanning means (actuator 14b) scans the subject (chart 14) in a direction orthogonal to the vibration axis 12aPY of the synthetic vibration direction (synthetic direction) of the plurality of vibration directions (12aP, 12aY).

[0053] (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. FIG. 27 is a schematic diagram of a blur evaluation apparatus 100c that executes a hand shake amount measurement method in the present embodiment. In FIG. 27, reference numeral 11 denotes a measurement camera (imaging means), which is installed on a vibration table (vibration means) 12. The vibration table 12 vibrates the measurement camera 11 around the arrow 12aP based on vibration waveform data 13. The vibration table 12 can be switched between a driving state (i.e., a vibrating state or a stationary state) by control. The measurement camera 11 faces a chart 14 as a subject, and a chart image captured by the measurement camera 11 during vibration by the vibration table is input to an image evaluation means 271. The image evaluation means 271 detects the contrast of the captured chart image and measures the degree of deterioration of the captured image due to vibration. Note that since details of the evaluation method are also disclosed in the image evaluation method in the prior art, the description thereof is omitted.

[0054] Next, with reference to FIG. 28, the operation of the image evaluation means 271 will be described. FIG. 28 is a block diagram of the image evaluation means 271. In FIG. 28, a stationary output 282 is image data (stationary measurement data) of a stationary image captured by the measurement camera 11 at a plurality of exposure times or brightness levels when the vibration means 12 is in a stationary state. A vibration output 281 is image data (vibration measurement data) of a vibration image captured by the measurement camera 11 at a plurality of exposure times or brightness levels when the vibration means 12 is in a vibrating state.

[0055] Based on the input vibration output 281, the image evaluation means 271 calculates information such as a blur amount and a defocus amount as a vibration-time change amount (vibration-time measurement data) 283. Similarly, based on the input stationary output 282, the image evaluation means 271 calculates a stationary-time change amount (stationary-time measurement data) 284 such as a defocus amount and a blur amount at rest. Note that the defocus amount and the blur amount at rest are generally referred to as a reference defocus amount, and thus are unified as a reference defocus amount in this specification. Also, the change amount such as the defocus amount and the blur amount measured during vibration is unified as a blur defocus amount in this specification.

[0056] The calculated measurement data 283 during vibration and the measurement data 284 at rest are compared by the division unit 285, and the blur amount data 286 is calculated by arithmetic processing such as subtraction. The blur amount data 286 corresponds to the blur amount data in the claims. Based on this blur amount data 286, blur evaluation is performed in the evaluation block 287.

[0057] Here, even when the vibration table 12 is in a stationary state, camera shake is applied to the measurement camera 11. The causes of camera shake are irregular vibrations input from the outside to the measurement environment, such as the shutter, mirror drive, lens drive inside the measurement camera 11, and the shaking of buildings and floors. In addition to camera shake, when the ISO sensitivity is set to a high sensitivity, noise that does not appear in the actual phenomenon may be superimposed on the image. Camera shake caused by irregular vibrations input from the outside to the measurement environment, such as the shutter, mirror drive, lens drive inside the measurement camera 11, and the shaking of buildings and floors, and the superimposition of noise due to high ISO sensitivity become disturbances when calculating the change amount and may inhibit the calculation of the pure blur amount. Below, the influence of disturbances on the reference blur amount and the blur amount will be described with respect to the reference blur amount.

[0058] FIG. 29 is a graph showing the reference blur amount in the order of exposure time in a state without camera shake or disturbances. In the graph of FIG. 29, the horizontal axis represents the exposure time, and the exposure time increases as it goes to the right. The vertical axis represents the reference blur amount, and the reference blur amount increases as it goes up. The unit of the vertical axis is, for example, the number of imaging pixels of the imaging device of the measurement camera 11. As shown in FIG. 29, the reference blur amount waveform 291 generally increases as the exposure time increases. This is because noise is superimposed on the captured image for a dark subject that requires a long exposure time.

[0059] Figure 30 is a graph showing the reference blur amount in a state with camera shake or disturbances in the order of exposure time. In the reference blur amount waveform 301, at a specific exposure time 302, the tendency of the reference blur amount 301a changes significantly. Such a phenomenon also occurs in the blur amount waveform (not shown). The reference blur amount, the blur amount due to shake, or the amount of shake representing the sudden change of these singular points is defined as the singular change amount. Also, a specific exposure time that significantly changes the tendency of the above change amount is defined as the specific exposure time (specific shooting condition). In order to avoid confusion in the explanation, the singular change amount occurring in the reference blur amount waveform is the singular blur amount, the singular change amount occurring in the blur amount due to shake waveform is the singular blur amount due to shake, and the singular change amount occurring in the shake amount data is the singular shake amount, and the terms are unified respectively.

[0060] Figures 31(a), 31(b), and 31(c) show the waveforms of camera shake during measurement of the reference blur amount. The horizontal axis is the elapsed time, and the vertical axis is the amount of shake on the imaging surface. The unit of the vertical axis is the number of imaging pixels, the same as in Figures 29 and 30. As shown in Figure 31(a), in the camera shake waveform 311, the camera shake 311a is large in the first half 312a of the exposure, and the camera shake 311b is small in the second half 312b of the exposure. In this case, since the exposure time 312 is long, the proportion occupied by the camera shake 311b is large and the influence of the camera shake 311a is small. Therefore, the reference blur amount does not increase. On the contrary, in Figure 31(b), since the exposure time 312 is short with respect to the camera shake 311a, the reference blur amount does not increase. However, in Figure 31(c), the exposure time 312 is approximately the same length as the length at which the maximum and minimum values of the camera shake 311a occur. Due to the occurrence of camera shake during exposure, the reference blur amount becomes extremely large and becomes the singular blur amount. Thus, due to camera shake, a singular blur amount occurs at a specific exposure time. The same phenomenon occurs even in the case of irregular disturbance vibration depending on the timing with the exposure time.

[0061] Next, with reference to FIGS. 32 and 33, the disturbance superposition that occurs when the ISO sensitivity becomes high sensitivity will be described with respect to the reference blur amount. FIG. 32 is an explanatory diagram of a method for obtaining the reference blur amount from an image captured by the measurement camera 11. To detect the contrast of the above-described image, the white and black chart 14 shown in FIG. 32 is used.

[0062] FIG. 33(a) is a graph showing the horizontal luminance change in the image captured with the chart 14 in a state without camera shake. The horizontal axis represents the pixels of the white-black boundary line of the chart 14 and the normal direction pixels in the imaging device, and the vertical axis represents the brightness of the normalized normal direction pixels. This brightness is detected by the luminance extraction line 330 in the captured image. As shown in FIG. 33(a), the luminance change waveform 331 has a predetermined slope 331a at the white and black boundary line. Then, the width 332 of the luminance change excluding the upper and lower 20 percent is defined as the reference blur amount. When there is camera shake as shown in FIG. 31(c), the luminance change waveform 331 shown in FIG. 33(b) is obtained, and the width 332 of the luminance change becomes thicker. Therefore, the reference blur amount increases.

[0063] Next, the relationship between the imaging sensitivity (ISO sensitivity) and the reference blur amount will be described. FIG. 33(c) shows the state of the chart 14 when shooting a low luminance with high sensitivity. In this state, the brightness varies due to illuminating the chart with low luminance. Also, a slight contrast change of the chart is increased for high-sensitivity shooting. As a result, chart unevenness as shown at 14a appears on the chart 14.

[0064] FIG. 33(c) is a shooting result in a state without camera shake or disturbance vibration, and unevenness peaks indicated by 331b may appear in the luminance change waveform 331 due to the chart unevenness 14a. However, since the width 332a of the unevenness peak is smaller than the width 332 of the luminance change, it is treated as noise. Therefore, the obtained reference blur amount does not change significantly from the reference blur amount when shooting at normal sensitivity.

[0065] FIG. 33(d) shows the shooting result in a state with camera shake or external disturbance vibration, and the unevenness peak indicated by 331b may appear in the luminance change waveform 331 due to the chart unevenness 14a. Here, as described with reference to FIG. 33(b), since the unevenness peak 331b due to the chart unevenness 14a is included within the width 332 of the luminance change, the width 332 of the luminance change becomes even wider. Therefore, in high-sensitivity shooting at a specific exposure time, the specific blur amount due to camera shake and external disturbance vibration appears.

[0066] FIG. 34 shows the shooting result of shooting a chart at normal brightness. FIG. 34 is a graph showing the reference blur amount in the order of exposure time in a state with camera shake or external disturbance vibration. In the reference blur amount waveform 341, the reference blur amount 341a is slightly larger at the specific exposure time 340.

[0067] FIG. 35 shows the shooting result of shooting a chart illuminated with low luminance at high sensitivity. FIG. 35 is a graph showing the reference blur amount in the order of exposure time in a state with camera shake or external disturbance vibration. In the reference blur amount waveform 351, a specific blur amount 351a appears at the specific exposure time 340. Thus, the reference blur amount shows a specific blur amount different from the reference blur amount at a specific exposure time due to shooting conditions such as shooting sensitivity, camera shake, and external disturbance vibration.

[0068] As described above, to evaluate the shake of the measurement camera 11, the image evaluation means 271 obtains the reference blur amount when the vibration table 12 is in a stationary state, and subtracts it from the blur amount obtained from the image evaluation means 271 in a state with shake. Here, consider the case where the measurement camera 11 is provided with a shake correction function (anti-shake function). At this time, camera shake and external disturbance vibration are reduced by shake correction.

[0069] FIG. 36(a) shows the amount of blur at each exposure time when the measurement camera 11 with the anti-vibration function activated is vibrated to create a blurred state. In FIG. 36(a), the horizontal axis represents the exposure time, and the vertical axis represents the amount of blur. The blur amount waveform 361 does not generate a specific blur amount due to the blur correction function. By subtracting the reference blur amount shown in FIG. 36(b) from the blur amount obtained here to obtain the blur amount, the blur amount waveform 362 shown in FIG. 36(c) is obtained. In FIG. 36(b), since there is a specific blur amount at the exposure time 340, a specific blur bottom also appears in the blur amount obtained by subtraction. Therefore, the blur amount becomes small at the exposure time 340. The blur amount in FIG. 36(c) represents the remaining blur correction after the anti-vibration function is activated, but incorrect blur correction performance is evaluated at the specific exposure time 340. In this way, accurate blur correction performance cannot be evaluated, so it is preferable to take measures against the specific blur amount.

[0070] (Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. Referring to FIG. 37, the operation of the image evaluation means 271 in this embodiment will be described. FIG. 37 is a block diagram of the image evaluation means 271. Since FIG. 37 is based on FIG. 28, the same numbers are assigned to the overlapping parts, and the description thereof is omitted.

[0071] 371 in FIG. 37 is a detection unit (detection means) for detecting disturbances. The detection unit 371 has, inside, a processing unit A373 for processing the data when the amount of blur is input, and a processing unit B374 for processing the data when the reference blur amount is input. The data processed by the processing unit A373 and the processing unit B374 is determined by the determination unit 375 for the presence or absence of disturbances. The detection unit 371 transmits the result of the internal determination unit 375 to the switching unit 376. When it is determined that there is no disturbance, the determination unit 375 transmits the blur amount 283 and the reference blur amount 284 to the A route, and the division unit 372 calculates the blur amount. When it is determined that there is a disturbance, the blur amount 283 and the reference blur amount 284 are transmitted to the B route, and after correction processing is performed by the correction unit (correction means) 377, the division unit 372 calculates the blur amount.

[0072] Next, with reference to FIGS. 38(a) and 38(b), the threshold value for the detection unit 371 in FIG. 37 to determine the influence of disturbance will be described with respect to the reference blur amount. 381 in FIG. 38(a) is a waveform graph showing the exposure time on the horizontal axis and the reference blur amount on the vertical axis. 382 in FIG. 38(a) is a waveform graph representing the change rate of the reference blur amount with respect to adjacent exposure times for the waveform graph 381. Also, +Th_a and -Th_a are the threshold values for determining the influence of disturbance. As shown by 381, a monotonically increasing waveform without a specific change amount shows a gentle slope like 382 when the change rate is calculated, and the change rate does not exceed the threshold value.

[0073] 383 and 384 in FIG. 38(b) are waveform graphs showing the same content as in FIG. 38(a). 383a in FIG. 38(b) indicates a specific exposure time at which a specific blur amount has occurred due to disturbance. In the case of the waveform of 383 where a reference blur amount such as such a specific point has occurred, a change rate with a steep slope as shown by 384 is calculated when the change rate is calculated. The detection unit 371 checks whether the change rate indicated by the specific exposure time 383a is equal to or greater than the threshold value, and determines the presence or absence of the influence of disturbance.

[0074] Next, with reference to FIGS. 39(a), 39(b), and 39(c), the operations of the processing unit A373, the processing unit B374, and the determination unit 375 incorporated in the detection unit 371 in FIG. 37 will be described. FIG. 39(a) is a flowchart showing the specific operation of the processing unit A373. When the blur amount is input to the detection unit 371, the processing unit A373 starts operating in step s391.

[0075] In step s392, the processing unit A373 calculates the change rate of the input reference blur amount. When determining whether the result of the change rate calculated in step s393 is less than the threshold value, in step s394, the result is recorded as Norm, and the operation ends in step s395. When it is determined in step s393 that the threshold value is exceeded, in step s396, the result is recorded as Err, and at the same time, the exposure time Tv_A exceeding the threshold value is recorded, and the operation ends.

[0076] Figure 39(b) is a flowchart showing the operation of the processing unit B374. Since the basic operation is the same as the operation of the processing unit A373 shown in Figure 39(a), details are omitted by assigning the same numbers to overlapping parts. After calculating the change rate of the reference blur amount in step s397, if the result is less than the threshold value, the result is recorded as Norm and the operation ends. When the result of the change rate of the reference blur amount exceeds the threshold value, in step s398, the result is recorded as Err, and at the same time, the exposure time Tv_B exceeding the threshold value is recorded.

[0077] Figure 39(c) is a flowchart showing the operation of the determination unit 375. After the operations of the processing unit A373 and the processing unit B374 are completed, the determination unit 375 starts the operation in step s399 based on the results. In step s3910, when the results of the respective processing units A373 and B374 shown in Figure 39(a) and Figure 39(b) are both Norm less than the threshold value, it is determined as no disturbance in step s3911, and the operation ends in step s3912. If the result of step s3910 is N, it proceeds to step s3913, and it is determined whether the results of the processing unit A373 and the processing unit B374 both exceed the threshold value and are Err. If the result of step 3913 is Y, in step s3914, the exposure time Tv_A exceeding the threshold value in the processing unit A373 is compared with the exposure time Tv_B exceeding the threshold value in the processing unit B374. When the exposure times Tv_A and Tv_B are the same exposure time, it is an environmental influence, and it proceeds to step s3911, and it is determined that there is no disturbance and the operation ends.

[0078] If the result of step s3914 is N, since the threshold is exceeded at different exposure times, the process proceeds to step s3915, where it is determined that there is interference, and the operation ends. If the result of step s3913 is N, since either one exceeds the threshold, the process proceeds to step s3915, where it is determined that there is interference and the operation ends.

[0079] Next, with reference to FIGS. 40(a), 40(b), 40(c), and 40(d), the determination of the presence or absence of interference determined in FIG. 39(c) will be described. In FIG. 40(a), the waveform graph 401 shows that the horizontal axis is the exposure time and the vertical axis is the change rate calculated from the reference blur amount, and the waveform graph 402 shows that the horizontal axis is the exposure time and the vertical axis is the change rate calculated from the blur blur amount. Since the change rates of the waveform graphs 401 and 402 do not exceed the threshold, the blur amount without the influence of interference can be calculated using these data.

[0080] Next, FIG. 40(b) will be described. The waveform graph 403 shown in FIG. 40(b) shows that the horizontal axis is the exposure time and the vertical axis is the change rate calculated from the reference blur amount, and the waveform graph 404 shows that the horizontal axis is the exposure time and the vertical axis is the change rate calculated from the blur blur amount. 403a indicates a specific exposure time at which the change rate exceeds the threshold. Although the change rates of the waveform graphs 403 and 404 both exceed the threshold, the specific exposure time at which the threshold is exceeded is the same specific exposure time 403a. Even if the blur amount is calculated using these data, since the specific change amount occurs at the same exposure time 403a, the influence is canceled out. Therefore, the blur amount without the influence of interference can be calculated.

[0081] Next, FIG. 40(c) will be described. Since FIG. 40(c) is based on FIG. 40(a), the description of overlapping parts will be omitted by assigning the same numbers. The waveform graph 405 shown in FIG. 40(c) has the exposure time on the horizontal axis and the change rate calculated from the reference blur amount on the vertical axis. The change rate of the waveform graph 405 exceeds the threshold, but the change rate of the waveform graph 402 does not exceed the threshold. When calculating the blur amount using these data, a blur amount as shown in FIG. 36(c) where the influence of disturbance appears at a specific exposure time will be calculated. Therefore, in this case, it is determined that there is disturbance, and the correction unit 377 in FIG. 37 performs correction processing on the reference blur amount that exceeds the threshold. Note that the data whose change rate exceeds the threshold is the first data determined to have disturbance. Also, the data whose change rate does not exceed the threshold is the second data determined to have disturbance.

[0082] Next, FIG. 40(d) will be described. Since FIG. 40(d) is based on FIG. 40(b), the description will be omitted by assigning the same numbers. The waveform graph 406 shown in FIG. 40(d) has the exposure time on the horizontal axis and the change rate calculated from the reference blur amount on the vertical axis. Also, 406a indicates a specific exposure time when the change rate exceeds the threshold. The change rates of the waveform graphs 406 and 404 both exceed the threshold. Also, the specific exposure times 406a and 403a when the change rate exceeds the threshold are different from each other. When calculating the blur amount using these data, a blur amount as shown in FIG. 36(c) where the influence of disturbance appears at a specific exposure time will be calculated. Therefore, in this case, it is determined that there is disturbance, and the correction unit 377 in FIG. 37 performs correction processing on the reference blur amount and the blur due to shake that exceed the threshold. Note that the data whose change rate exceeds the threshold is the first data determined to have disturbance.

[0083] FIG. 41 will sequentially describe several correction methods performed by the correction unit 377 in FIG. 37 with respect to the waveform of the reference blur amount.

[0084] (1) In Fig. 41(a), the reference blur line obtained by averaging the reference blur amount slopes for each exposure time is used as the new reference blur amount. In Fig. 41(a), the slope of the line connecting the reference blur amounts at exposure times 410a and 4100a of the reference blur waveform 412 is obtained (the ratio of adjacent reference blur amounts at continuously varying exposure times is obtained). Similarly, the slope of the line connecting the reference blur amounts at exposure times 4100a and 410b is obtained. In this way, the slopes for all exposure times are obtained, and an adjustment blur amount (straight line) 413 with the average slope of these slopes is set starting from, for example, exposure time 410a, and the intercepts of this straight line with each exposure time are used as the adjustment blur amounts. The adjustment blur amount 413 corresponds to the correction change amount. Here, although the front and rear waveforms 412a and 412b of the specific blur amount 412c have large slopes, since the directions of the slopes are opposite to each other, they are canceled out by averaging. That is, the influence of the specific blur amount on the averaging of the slopes is small. Using the difference between the adjustment blur amount obtained from the straight line 413 and the blur amount in Fig. 36(a), the blur amount can be stably obtained.

[0085] (2) The method in Fig. 41(b) will be described. Since it can be seen from Fig. 41(a) that the waveforms 412a and 412b with large slopes with respect to the average slope 413 are present, the exposure time 4100d that generates the specific blur amount can be found. Therefore, in Fig. 41(b), only the specific blur amount at the exposure time 4100d is obtained as the average of the adjacent exposure times 410d and 410e, and used as the adjustment blur amount 414c. The adjustment blur amount 414c corresponds to the correction change amount. Using the difference between the adjustment blur amount 414 obtained in this way and the blur amount in Fig. 36(a), the blur amount can be stably obtained.

[0086] (3) The method in Fig. 41(c) will be described. Fig. 41(c) obtains the adjustment blur amount using the waveform (correction change amount) 415 obtained by linearly approximating the reference blur waveform 412 obtained in Fig. 41(a). Using the difference between the adjustment blur waveform 415 obtained in this way and the blur amount in Fig. 36(a), the blur can be stably obtained. The waveform used as the basis for the linear approximation is not limited to the reference blur waveform 412 in Fig. 41(a), and for example, the adjustment blur amount 414 in Fig. 41(b) may also be used.

[0087] (4) Figure 41(d) obtains the adjusted reference blur amount using the straight line (correction change amount) 416 obtained by averaging the reference blur amounts for each exposure time of the reference blur waveform 412 obtained in Figure 41(a). Using the difference between the adjusted blur waveform (straight line) 416 obtained in this way and the blur amount in Figure 36(a), the blur amount can be stably obtained. The waveform that is the basis for the average straight line is not limited to the reference blur waveform 412 in Figure 41(a), and may also be the adjusted blur amount 414 in Figure 41(b).

[0088] The means for adjusting and calculating the specific blur amount to obtain the adjusted blur amount in the above (1) to (4) is the correction unit 377 shown in Figure 37. As described above, with the correspondence of this embodiment, even if there is an external disturbance in either the reference blur amount or the blur amount data, the external disturbance can be corrected and the camera blur can be accurately evaluated.

[0089] (Sixth Embodiment) Next, the sixth embodiment of the present invention will be described. Referring to Figure 42, the operation of the image evaluation means 271 in this embodiment will be described. Figure 42 is a block diagram of the image evaluation means 271. Since Figure 42 is based on Figures 28 and 37, the same numbers are used for overlapping parts and the description is omitted. In Figure 42, 421 is a detection unit (detection means) for detecting external disturbances. The detection unit 421 has a processing unit 424 inside that processes the data when the blur amount is input. The data processed by the processing unit 424 is determined by the determination unit 425 for the presence or absence of external disturbances. The detection unit 421 transmits the result of the internal determination unit 425 to the switching unit 376.

[0090] When the determination unit 425 determines that there is no external disturbance, it transmits the blur amount data 286 to the A route, and the blur evaluation is performed in the evaluation unit 423. When it is determined that there is an external disturbance, the blur amount data 286 is transmitted to the B route, correction processing is performed in the correction unit (correction means) 422, and then the blur evaluation is performed in the evaluation unit 423.

[0091] Next, with reference to FIGS. 43(a) and 43(b), the operations of the processing unit 424 and the determination unit 425 incorporated in the detection unit 421 will be described. FIG. 43(a) is a flowchart showing the specific operation of the processing unit 424. Since FIG. 43(a) is based on FIG. 13(a), the description of overlapping parts will be omitted by assigning the same numbers.

[0092] When the blur amount is input to the detection unit 421, the processing unit 424 starts operating. In step s431, the processing unit 424 calculates the change rate of the input reference blur amount. If the change rate is less than the threshold value, the result is recorded as Norm in step s432, and the operation ends. Since the change rate calculation method and the threshold determination method are the same as those described in FIGS. 38(a) and 38(b), the description is omitted. If it is determined that the change rate exceeds the threshold value, the result is recorded as Err in step s433, and at the same time, the exposure time exceeding the threshold value is recorded as Tv_Blur, and the operation ends.

[0093] FIG. 43(b) is a flowchart showing the operation of the determination unit 425 in the detection unit 421 shown in FIG. 42. Since FIG. 42(b) is based on FIG. 13(c), the description of overlapping parts will be omitted by assigning the same numbers. The determination unit 425 starts operating based on the result after the operation of the processing unit 424 ends.

[0094] In step s434, if the result of the processing unit 424 shown in FIG. 43(a) is Norm less than the threshold value, in step s435, it is determined that there is no disturbance and the operation ends. If the result of step s434 is N, in step s436, it is determined that the blur amount data has disturbance, and the operation ends. The blur amount data with disturbance is the blur amount data determined to have disturbance.

[0095] When it is determined that there is disturbance by the disturbance presence / absence determination described in FIGS. 43(a) and 43(b), the correction unit 422 corrects the disturbance. Since the correction method is the same as that in FIGS. 41(a), 41(b), and 41(c), the detailed description is omitted.

[0096] As described above, according to this embodiment, even when there is noise in the shake amount data, the noise can be corrected and the camera shake can be accurately evaluated.

[0097] (Embodiment 7) Next, a seventh embodiment of the present invention will be described. FIG. 44 is a schematic diagram of a shake evaluation apparatus 100d that executes the hand shake amount measurement method in this embodiment. In FIG. 44, 11 is a measurement camera (imaging means) installed on a vibration table (vibrating means) 12. The measurement camera 11 and the vibration table 12 are controlled through a control unit 443 of a computer 442. The vibration table 12 vibrates the measurement camera 11 around the arrow 12aP based on vibration waveform data 13 stored in a memory 444 in the computer 442. The measurement camera 11 faces a chart 14 that is the subject, and a chart image captured by the measurement camera 11 while being vibrated by the vibration table 12 is input to an image evaluation means 446 in the computer 442. The image evaluation means 446 detects the width of the boundary between two adjacent colors in the captured chart image and measures the degree of deterioration of the captured image due to vibration. Then, the image evaluation means 446 evaluates the shake of the measurement camera from the degree of deterioration. Since the details of the evaluation method are the same as those of the prior art, the description thereof is omitted.

[0098] In order to evaluate the shake of the measurement camera 11, a reference blur amount of the measurement camera that is superimposed on the measurement camera signal in a non-shaken state is obtained in advance and subtracted from the camera signal in a shaken state. Since the shake is evaluated using the exposure time as a parameter, the reference blur amount of the measurement camera is obtained for each exposure time. Here, the exposure time, aperture value, and ISO sensitivity of the measurement camera 11 are problematic. In addition to these, the reference blur amount of the measurement camera also changes due to external influences such as building vibrations, lighting conditions such as shadows of the chart due to the lighting direction, distance errors between the chart and the measurement camera, and measurement environments such as warping of the chart. This is because the reference blur amount of the measurement camera in a shaken state and the reference blur amount of the measurement camera in a non-shaken state are different due to this change, and even if the two are subtracted, the reference blur amount of the measurement camera cannot be canceled out and the correct shake cannot be obtained. Therefore, it is necessary to obtain a stable reference blur amount of the measurement camera regardless of the measurement environment.

[0099] In FIG. 44, reference numeral 441 denotes a reference camera (reference determination means), which is photographing a chart 14 having substantially the same composition as the measurement camera 11. Here, the reference camera 441 is a mass-produced product having a known point spread function, and a product having a point spread function with small variation among individuals of the same model and a small dispersion in a normal distribution is selected. When evaluating the shake of the camera at various locations, a camera of the same model is used as the reference camera. Here, the blur amount when the chart 14 is photographed in advance by the reference camera 441 for each exposure time is defined as the specified blur amount.

[0100] Next, referring to FIG. 45, the chart in the present embodiment will be described. FIG. 45 is a plan view of a blur measurement chart. The chart 14 is a blur measurement chart displayed on a monitor as shown in FIG. 45. The blur measurement chart is a chart used as a subject when measuring the hand shake correction effect. The black region 141 is a region with low brightness painted in black (the first color). The white region 142 is a region with high brightness of white (the second color). The shooting area marker 143 is a marker used as a guide for setting the shooting area. The blur measurement chart is not limited to that shown in FIG. 45, and various charts can be applied. For example, instead of a combination of black and white as shown in FIG. 45, it may be a pattern consisting of a plurality of color regions having chroma. At this time, it is desirable that the reflectance ratio between the high-brightness color and the low-brightness color is 4:1 or more. Further, the blur measurement chart may be not only a geometric pattern but also a pattern incorporating a real photograph in part. That is, the blur correction chart may be a chart including a plurality of color regions.

[0101] In the present embodiment, the amount of blur in the image is evaluated by measuring the blur of the image of the boundary between different color regions of the blur measurement chart. The color in the color region here is a concept including black, gray, and white without chroma, and also including colors with chroma. Further, blur refers to a phenomenon in which the focal plane of the lens and the imaging surface of the imaging device are displaced, or the sharpness of the captured image decreases due to hand shake or the like. Blur may also occur by image processing of image data. The amount of blur refers to the quantification of the size of blur. The boundary width between the black region 141 and the white region 142 of the chart 14 can be adjusted by the image adjustment means (changing means) 447. When there are a plurality of reference blur amount confirmation locations, the image adjustment means 447 can adjust the boundary width at any location within the chart.

[0102] The reference camera 441 compares the results of shooting for each exposure time with the reference camera reference blur amount obtained by the reference camera image evaluation means (blur amount calculation means) 448 and the specified blur amount determined in advance by the detection means 449. The image adjustment means 447 controls the boundary width of the chart 14 based on the result. For this reason, the measurement camera reference blur amount of the measurement camera 11 can be stably obtained regardless of the measurement environment.

[0103] Next, with reference to FIG. 46, the blur amount will be described. FIG. 46 is a graph showing the change situation of the normalized level value at the boundary between the black region and the white region of the image obtained by shooting the chart 14 with the camera. The horizontal axis represents the number of pixels of the imaging element in the camera, and the vertical axis represents the level value of the normalized image signal (here, the normalized luminance). Note that by normalization, the level value of the image signal in the black region is set to 0, and the level value of the image signal in the white region is set to 255. In FIG. 46, the blur amount of the image is the boundary portion between P1 in the white region and P2 in the black region shown at A, and is the distance during which the level value of the normalized image signal changes from 0 to 255. Note that since the details of the blur amount calculation method are prior art, the description here is omitted.

[0104] Next, with reference to FIG. 47, the blur evaluation method of the measurement camera will be described. FIG. 47 is a simple flowchart of the blur evaluation method of the measurement camera when shooting with the reference camera and the measurement camera is performed simultaneously.

[0105] First, in step s471, the exposure times of the measurement camera 11 and the reference camera 441 are set. For example, when the focal length of the shooting lens in the measurement camera 11 is 100 mm and the size of the imaging element is the full-size format (36 mm horizontally and 24 mm vertically), it is initially set to 1 / 100 second.

[0106] Subsequently, in step s472, the reference camera 441 shoots the chart 14, and the reference camera reference blur amount is obtained by the reference camera image evaluation means 448. The reference camera reference blur amount is obtained by obtaining the blur amount from the boundary width between the black region and the white region of the image of the chart 14 shot with the reference camera at rest as described above.

[0107] Subsequently, in step S473, the control unit 443 determines whether the ratio of the specified blur amount of the reference camera 441 to the reference blur amount of the reference camera obtained in step S472 (hereinafter referred to as the blur amount ratio) is 1. When the blur amount ratio is 1, it means that the specified blur amount of the reference camera 441 coincides with the reference blur amount, resulting in an ideal state. However, a range may be set for the blur amount ratio, and the determination may be made so that it falls within that range (for example, within ±5 percent error). When there are multiple locations for confirming the reference blur amount of the reference camera, the blur amount ratio is confirmed at all locations. When the blur amount ratios at all locations are 1 or within the set range, the process proceeds to step S475. On the other hand, if not, the process proceeds to step S474.

[0108] In step S474, based on the blur amount ratio obtained in step S473, the boundary width between the black region 141 and the white region 142 of the chart 14 is adjusted. For example, when the reference blur amount of the reference camera obtained in step S473 is 10 percent larger than the specified blur amount, the boundary width of the chart 14 is narrowed according to that amount. Conversely, when it is 10 percent smaller than the specified blur amount, the boundary width of the chart 14 is widened according to that amount. By repeating steps S472 to S474, the reference blur amount of the reference camera is brought closer to the specified blur amount.

[0109] Here, with reference to FIG. 48, the relationship between the blur amount of the reference camera 441 and the boundary width of the chart 14 will be described. FIG. 48(a) is a graph showing the change situation of the normalized level value at the boundary between the black region and the white region of the image of the chart 14, and BI, CI, and PI each represent the boundary width. FIG. 48(b) is a graph showing the change situation of the normalized level value at the boundary between the black region and the white region of the captured image of the chart 14 taken by the reference camera 441, PO is the boundary width of the specified blur amount, and BO and CO each represent the boundary width of the reference blur amount. The boundary widths BO, CO, and PO in FIG. 48(b) correspond to the results obtained by applying the PSF described later to the boundary widths BI, CI, and PI in FIG. 48(a), respectively. In both FIGS. 48(a) and 48(b), the horizontal axis represents the number of pixels of the imaging element in the camera, and the vertical axis represents the level value of the normalized image signal.

[0110] Since the point spread function PSF can be regarded as the function of the image to be captured and the transfer function of the captured image, when the captured image of the reference camera 441 is O and the image of the chart 14 is I, the following relational expression holds.

[0111]

Equation

[0112] In this embodiment, since the PSF is considered to be divided into two parts: PSF1 possessed by the camera itself and PSF2 representing the image influencing factors such as the measurement environment, Equation (1) is expressed as the following Equation (2).

[0113]

Equation

[0114] The PSF1 possessed by the camera itself represents the resolution of the camera, and is a function representing the deviation between the focal plane of the lens and the imaging plane of the camera's imaging element, image processing within the camera, lens aberration, etc., corresponding to a known image acquisition state. Although this PSF1 cannot be arbitrarily controlled by the measurer, it can be grasped in advance. Therefore, when selecting the reference camera 441, by selecting a PSF1 with a normal distribution and a small variance, the influence of the camera itself on the captured image can be reduced.

[0115] The PSF2 representing the image influencing factors such as the measurement environment is a function representing the influence on the image due to disturbances such as building sway, lighting conditions, distance error between the chart and the measurement camera, and warping of the chart, and varies depending on the situation of the measurement environment. Therefore, it is difficult to grasp in advance and cannot be arbitrarily controlled by the measurer. PSF2 corresponds to an unknown image acquisition state. Thus, the captured image O is an image obtained by applying both a known image acquisition state and an unknown image acquisition state to the chart.

[0116] The image I of Chart 14 is the image captured by the reference camera 441, and in Equation (2), it can be arbitrarily controlled by the only measurer. Therefore, the captured image O of the reference camera 441 in Equation (2) is affected by the PSF1 of the camera itself that cannot be controlled by the measurer and the PSF2 representing the image influencing factors such as the measurement environment. However, by controlling the image I of Chart 14, it can be arbitrarily controlled. When this is represented in FIG. 48, when the boundary width of the reference blur amount is larger than the boundary width of the specified blur amount PO like CO, the boundary width on the image I side of Chart 14 may be narrowed from CI to PI. Also, when the boundary width of the reference blur amount is smaller than the boundary width of the specified blur amount PO like BO, the boundary width on the image I side of Chart 14 may be narrowed from BI to PI. From the above, in this embodiment, by controlling the image I of Chart 14, that is, the boundary width, the blur amount obtained from the captured image O of the reference camera 441 is made constant, so that the influence on the image due to the measurement environment is canceled, and a stable blur amount can always be obtained.

[0117] In step s475 of FIG. 47, the chart 14 is photographed by the measurement camera 11, and the measurement camera reference blur amount is obtained by the image evaluation means 446. Subsequently, in step s476, the measurement camera reference blur amount obtained in step s475 is recorded in the storage unit 445 for each exposure time (in this example, 1 / 100 second for the first time).

[0118] Steps s477 to s479 are the same as steps s472 to s474. Here, it is confirmed whether the reference camera reference blur amount deviates from the specified blur amount during the measurement of the measurement camera reference blur amount in steps s475 and 476, and the boundary width of Chart 14 is adjusted as necessary.

[0119] In step s4710, it is determined whether the measurement of the measurement camera reference blur amount has been completed. If the recording of the measurement camera reference blur amount in step s476 has been completed, the process proceeds to step s4711. On the other hand, if the recording of the measurement camera reference blur amount has not been completed, the process returns to step s477.

[0120] In step s4711, it returns to step s471 until the exposure time measured by the measurement camera 11 ends. When the measurement at all exposure times is completed, it proceeds to step s4712. In step s4712, the measurement camera 11 is vibrated by driving the vibration table 12 using the vibration waveform data 13. Subsequently, in step s4713, the exposure time of the measurement camera 11 is set in the same manner as in step s471.

[0121] Subsequently, in step s4714, the chart 14 is photographed with the measurement camera 11, and the amount of blur is obtained by the image evaluation means 446. Here, the amount of blur is the amount of blur generated in the photographed image when the camera is vibrated. Subsequently, in step s4715, the obtained amount of blur is recorded in the storage unit 445 for each exposure time (in this example, 1 / 100 second for the first time). Subsequently, in step s4716, the control unit 443 determines whether the shooting of the specified number of images has been completed at the same exposure time. For example, when shooting 100 images, it returns to step s4714 until 100 images are shot, and proceeds to step s4721 after 100 images are shot.

[0122] Steps s4717 to s4719 are the same as steps s472 to s474. Here, it is confirmed whether the reference camera reference blur amount deviates from the specified blur amount during the measurement of the measurement camera blur amount from steps s4714 to s4716, and the boundary width of the chart 14 is adjusted as necessary.

[0123] In step s4720, the control unit 443 determines whether the measurement of the measurement camera blur amount has been completed. When the shooting of the specified number of images in step s4716 has been completed, it proceeds to step s4721. On the other hand, when the shooting of the specified number of images has not been completed, it returns to step s4717.

[0124] In step s4721, the process returns to step s4713 until the exposure time measured by the measurement camera 11 ends. When the measurements for all exposure times are completed, the process exits step s4721 and the flow ends. When evaluating camera shake, the value obtained by subtracting the measurement camera reference blur amount for each exposure time recorded in step s476 from the average blur amount for each exposure time recorded in step s4715 is defined as the measurement camera shake amount.

[0125] Next, with reference to FIG. 49, an example in the case where the chart 14 is a paper chart instead of a monitor will be described. FIG. 49 is a schematic diagram of the blur evaluation apparatus 100d when the chart 14 is a paper chart.

[0126] A plurality of paper charts 14a to 14n are prepared, and the boundary widths of the respective charts gradually increase. Any one of the paper charts 14a to 14n is attached to a suction panel (not shown) facing the measurement camera 11 and the reference camera 441. Then, the reference camera reference blur amount is output to the image selection means (changing means) 4410. The image selection means 4410 changes the boundary width of the chart by displaying an appropriate chart based on the ratio of the input reference camera reference blur amount to the specified blur amount. For example, when the reference camera reference blur amount is 10% larger than the specified blur amount, a chart number with a narrower boundary width than the currently used chart is displayed according to the magnitude. Conversely, when the reference camera reference blur amount is 10% smaller than the specified blur amount, a chart number with a wider boundary width is displayed according to the magnitude. The measurer selects the charts 14a to 14n according to the display, attaches them to the suction panel, and checks the reference camera reference blur amount again. When there are a plurality of reference blur amount confirmation locations, charts with different boundary widths are partially replaced so that the reference camera reference blur amount matches the specified blur amount at all confirmation locations. In this way, the measurement camera reference blur amount that changes due to the influence of the measurement environment or the like can always be stabilized by feedback to the chart 14 based on the reference camera reference blur amount, and the camera shake can be evaluated more accurately.

[0127] (Eighth Embodiment) Next, the eighth embodiment of the present invention will be described. In the seventh embodiment, the measurement camera reference blur amount was stabilized by feeding back the shooting result of the reference camera 441 to the chart 14 simultaneously with the measurement of the reference blur amount by the measurement camera 11. On the other hand, in the present embodiment, the shooting of the reference camera 441 and the measurement of the reference blur amount of the measurement camera 11 are performed separately, and after feeding back the shooting result of the reference camera 441 to the chart 14, the measurement of the measurement camera 11 is performed to stabilize the measurement camera reference blur amount.

[0128] Referring to FIG. 50, the configuration of the camera blur evaluation method in the present embodiment will be described. Note that since the configuration in the present embodiment is only to separate the measurement camera 11 and the reference camera 441 in the seventh embodiment into two, the details of each block will be omitted.

[0129] FIG. 50(a) is a schematic diagram of the blur evaluation apparatus 100e when measuring the reference camera reference blur amount with the reference camera 441 and adjusting the boundary width of the chart 14. The reference camera 441 is installed at a position facing the chart 14, and each means in the reference camera 441 and the computer 442 is controlled by the control unit 443.

[0130] FIG. 50(b) is a schematic diagram of the blur evaluation apparatus 100f when measuring the measurement camera reference blur amount with the measurement camera 11. The measurement camera 11 is installed at the position where the reference camera 441 performed the measurement with respect to the chart 14, and each means in the measurement camera 11 and the computer 442, and the vibration table 12 are controlled by the control unit 443.

[0131] Next, referring to FIG. 51, the blur evaluation method of the measurement camera 11 will be described. FIG. 51 is a simple flowchart of the blur evaluation method of the measurement camera 11 when the shooting of the reference camera and the measurement camera are performed separately. Note that the description of the same blocks as the flowchart of FIG. 47 will be omitted.

[0132] First, in step S511, the reference camera 441 is placed at a position facing the chart 14. At this time, the shooting distance of the reference camera 441 is set to a distance at which the range within the shooting area marker of the chart 14 is almost entirely shown on the screen. If the reference camera 441 can be placed at a position facing the chart 14, proceed to step S471.

[0133] In step S512, the measurement camera 11 is placed at a position facing the chart 14. At this time, the shooting distance of the measurement camera 11 is set to a distance at which the range within the shooting area marker of the chart 14 is almost entirely shown on the screen, similar to the reference camera 441 in step S511. After the measurement camera 11 is placed at a position facing the chart 14, proceed to step S471.

[0134] In this way, the measurement camera reference blur amount that changes due to influences such as the measurement environment can be stabilized by feedback to the chart 14 based on the reference camera reference blur amount, and the blur of the camera can be evaluated more accurately.

[0135] (Embodiment 9) Next, Embodiment 9 of the present invention will be described. FIG. 52 is a schematic diagram of the blur evaluation apparatus 100g in this embodiment. In this embodiment, as shown in FIG. 52, the measurement camera 11 is measured in the same state as in the fourth embodiment. That is, the measurement camera 11 is installed on the vibration table (vibration means) 12. The vibration table 12 vibrates the measurement camera 11 around the arrow 12aP based on the vibration waveform data 13. Also, the vibration table 12 can be switched between a vibration state and a stationary state by control. The measurement camera 11 faces the chart 14 which is the subject, and the chart image captured by the measurement camera 11 while being vibrated by the vibration table is input to the resolution calculation means 500. Also, the brightness of the subject (shooting environment) can be changed by the illumination 14c to obtain a chart image. The chart to be photographed at this time can be the same as that shown in FIG. 32 of the fourth embodiment. If there are other charts that can measure the so-called resolution, they can also be used.

[0136] In this embodiment, the resolution may be defined based on the width of the luminance change. Specifically, when the width 332 of the luminance change in FIG. 33 is narrow, it can be considered that the resolution is high, and when the width 332 of the luminance change is wide, the resolution is low. The resolution calculation means 500 obtains the resolution from the imaging magnification at the time of shooting, the information of the chart, the width 332 of the above-described luminance change, and the like.

[0137] In the description of this embodiment, the output of the resolution calculation means 500 is performed using the term "resolution" as described above. As is clear from the measurement method in FIG. 52, since the factor that controls the resolution is so-called image blur, it may be that high resolution = less blur and low resolution = more blur. That is, although the vertical axis in FIGS. 53 to 56 described later is the resolution, it may be regarded as the amount of blur (the amount of blur is less at the top). Also, in FIGS. 53 to 56, the horizontal axis is the brightness of the subject, but the exposure time may be used. That is, in FIG. 52, an image is acquired while changing the brightness of the subject using the illumination 14c. At this time, the darker the brightness, the longer the exposure time. That is, the brightness and the exposure time correspond. When it is bright, the exposure time is short, and when it is dark, the exposure time is long. Although the horizontal axis in FIGS. 53 to 56 described later is the brightness, it may be regarded as the exposure time (the exposure time is longer on the right). Actually, FIG. 57 shows an example in which the horizontal axis is the exposure time. Also, a blur evaluation method described later is performed using each of the relationship between brightness and resolution and the relationship between exposure time and resolution. If there is a difference of a threshold value or more between the values of both, re-evaluation may be performed, and the final blur evaluation may be performed using both results.

[0138] FIGS. 53 to 56 are explanatory diagrams of the blur evaluation method and are diagrams showing the relationship between brightness and resolution. In each of the graphs in FIGS. 53 to 56, the horizontal axis represents brightness and the vertical axis represents resolution. As shown in FIG. 52, the measurement camera 11 is installed on the vibration table 12, and the graph shows the result of processing the acquired image with the resolution calculation means 500 while changing the brightness with the illumination 14c. The horizontal axis in FIGS. 53 to 56 becomes darker as it goes to the right. As it gets darker, the resolution decreases due to the influence of blur. Therefore, the graph slopes downward to the right.

[0139] Also, FIGS. 53 to 56 each show the results of the measurement camera 11 where (a) is determined to have high performance in the blur evaluation and the results of the measurement camera 11 where (b) is determined to have low performance in the blur evaluation. Hereinafter, several preferable blur evaluation methods will be shown based on the relationship between brightness or exposure time and resolution.

[0140] Referring to FIG. 53, a method for evaluating the anti-vibration performance by the resolution calculation means (tilt calculation means and anti-vibration evaluation means) 500 linearly approximating the resolution in a certain brightness range (or a certain exposure time range) will be described. In FIG. 53, 501a and 501b indicate the resolution, and 511a and 511b indicate the straight lines obtained by linearly approximating the resolution, respectively. Assuming that data is measured at 7 points indicated by black circles in the brightness range shown in FIG. 53. Let the slopes of the straight lines 511a and 511b obtained by linearly approximating this range be A and B, respectively. As is apparent from FIG. 53, the slope A of FIG. 53(a) determined to have high performance in the blur evaluation is smaller than the slope B of FIG. 53(b) determined to have low performance in the blur evaluation. That is, it may be determined that the smaller this slope is, the better the performance.

[0141] Referring to FIG. 54, a method for evaluating the anti-vibration performance by the resolution calculation means (tilt calculation means and anti-vibration evaluation means) 500 obtaining the slope of a straight line connecting two resolutions with different brightnesses (or exposure times) will be described. In FIG. 54, the same numbers are assigned to the same meanings as in FIG. 53. In FIG. 54, 504a and 504b indicate the predetermined brightnesses defining the straight line, and 505a and 505b indicate another brightness different from 504a and 504b and defining the straight line. Also, 508a indicates the straight line passing through the resolutions of 504a and 505a, and 508b indicates the straight line passing through the resolutions of 504b and 505b. Also, let the slopes of the straight lines 508a and 508b be A and B, respectively. As is apparent from FIG. 54, the slope A of FIG. 54(a) determined to have high performance in the blur evaluation is smaller than the slope B of FIG. 54(b) determined to have low performance in the blur evaluation. That is, it may be determined that the smaller this slope is, the better the performance.

[0142] Referring to FIG. 55, a method for evaluating the anti-vibration performance from the intersection of a straight line obtained within a range of a predetermined brightness (or exposure time) and a constant brightness range will be described. In FIG. 55, those having the same meaning as in FIGS. 53 and 54 are assigned the same numbers. In FIG. 55, 506a, 507a, 506b, and 507b indicate predetermined brightnesses used for calculating the slope. Also, 521a indicates a straight line passing through the resolutions of 506a and 507a, and 521b indicates a straight line passing through the resolutions of 506b and 507b. Further, 522a and 522b respectively indicate the resolutions at brightnesses 504a and 504b, 523a indicates the brightness corresponding to the intersection of the straight line 521a and 522a, and 523b indicates the brightness corresponding to the intersection of the straight line 521b and 522b. A is synonymous with 523a, and B is synonymous with 523b. As is clear from FIG. 55, the brightness A in FIG. 55(a) which is determined to have high performance in the blur evaluation is at a darker position (toward the right in FIG. 55) than the brightness B in FIG. 55(b) which is determined to have low performance in the blur evaluation. That is, it may be determined that the side with the darker brightness corresponding to this intersection has better performance.

[0143] Referring to FIG. 56, a method for evaluating the anti-vibration performance based on the intersection of straight lines obtained in two different ranges will be described. In FIG. 56, those having the same meaning as in FIGS. 53 to 55 are assigned the same numbers. Similar to FIG. 54, 508a indicates a straight line passing through the resolutions of 504a and 505a, and 508b indicates a straight line passing through the resolutions of 504b and 505b. Also, similar to FIG. 55, 521a indicates a straight line passing through the resolutions of 506a and 507a, and 521b indicates a straight line passing through the resolutions of 506b and 507b. Further, 531a indicates the brightness corresponding to the straight line 508a and the straight line 521a, and 531b indicates the brightness corresponding to the straight line 508b and the straight line 521b. A is synonymous with 531a, and B is synonymous with 531b. As is clear from FIG. 56, the brightness A in FIG. 56(a) which is determined to have high performance in the blur evaluation is at a darker position (toward the right in FIG. 56) than the brightness B in FIG. 56(b) which is determined to have low performance in the blur evaluation. That is, it may be determined that the side with the darker brightness corresponding to this intersection has good performance.

[0144] In the examples of FIGS. 53 to 56, an example of performing blur evaluation using predetermined brightness values 504, 505, 506, and 507 was shown. In addition, a method for determining the data range referred to by the tilt calculation means or the like will be described with reference to FIG. 57.

[0145] In FIG. 57, the horizontal axis represents the exposure time, and the vertical axis represents the resolution. In FIG. 57, the same components as those in FIGS. 53 to 56 are denoted by the same reference numerals. In FIG. 57, f written as 1 / f is the equivalent focal length (equivalent focal length in terms of 35 mm format) of the photographing lens used in the measurement camera 11. The exposure time of 1 / f is the exposure time at which blur is said to start becoming noticeable when taking a photograph by hand conventionally. That is, if the equivalent focal length (f) is 100 mm, 1 / f is an exposure time of 1 / 100 [s]. 554 indicates the exposure time at which blur has no effect, and 555 indicates the exposure time of 1 / f. The other reference numerals will be described in the description of each figure.

[0146] With reference to FIG. 57(a), a method for determining the data or data range to be referred to with reference to 1 / f will be described. In FIG. 57(a), first, the exposure time of 1 / f is set as the first reference (= exposure time 555). Next, a point where the exposure time is longer by the amount indicated by arrow 560 is set as the second reference (= exposure time 561). The length of arrow 560 may be determined in advance. For example, the exposure time may be made 16 times longer (= 4 steps). A straight line is determined using these two points or the data range sandwiched between these two points. In FIG. 57(a), the straight line passing through the two points is indicated by 562.

[0147] Referring to FIG. 57(b), a method for determining the data or data range to be referred to by utilizing the resolution degradation will be described. In FIG. 57(b), first, the resolution 570 of the exposure time 554 that is sufficiently bright and has no blurring effect is obtained. From this, the resolution 572 that has decreased by a specified amount 571 is obtained. The specified amount 571 may be set to a value that is convenient for measurement. If the amount is too small, the measurement will not be stable, and if the amount is too large, the evaluation will be performed in a range where the blurring effect is too large. The exposure time 573 at which the resolution 572 intersects the measurement data 501 is used as the first reference. Next, the point where the exposure time is longer by the amount indicated by the arrow 574 is used as the second reference (= exposure time 561). The length of the arrow 574 may be determined in advance. For example, it may be set such that the exposure time becomes four times longer (= two steps). A straight line is determined using these two points or the data range sandwiched between the two points. In FIG. 57(b), the straight line passing through the two points is indicated by 576.

[0148] Referring to FIG. 57(c), a method for determining the data or data range to be referred to by utilizing the resolution degradation in the same manner as in FIG. 57(b) will be described. In FIG. 57(c), an acceptable resolution 580 is determined in advance. The exposure time 581 at which this resolution 580 intersects the measurement data 501 is used as the first reference. Next, the point where the exposure time is longer by the amount indicated by the arrow 582 is used as the second reference (= exposure time 583). The length of the arrow 582 may be determined in advance. For example, it may be set such that the exposure time becomes four times longer (= two steps). A straight line is determined using these two points or the data range sandwiched between the two points. In FIG. 57(c), the straight line passing through the two points is indicated by 584.

[0149] Referring to FIG. 57(d), a method for determining reference data or a data range by utilizing the performance when no blur correction is performed will be described. 590 in FIG. 57(d) shows the resolution 591 at the exposure time 555(1 / f) when the blur correction function of the measurement camera 11 is disabled. The exposure time 592 at which the resolution 591 intersects the measurement data 501 is taken as the first reference. Next, a point where the exposure time is longer by the amount indicated by the arrow 593 is taken as the second reference (= exposure time 594). The length of the arrow 593 may be determined in advance. For example, it may be set such that the exposure time becomes four times longer (= two steps). A straight line is defined using these two points or the data range sandwiched between the two points. In FIG. 57(d), the straight line passing through the two points is indicated by 595.

[0150] (Other Embodiments) The present invention can also be realized by supplying a program that realizes one or more 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 (for example, ASIC) that realizes one or more functions.

[0151] According to each embodiment, it is possible to provide a blur evaluation device, a blur evaluation method, and a program that can accurately evaluate the blur of the photographing means. Also, according to each embodiment, it is possible to provide a method for manufacturing a photographing means capable of performing accurate blur correction.

[0152] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

Description of Reference Numerals

[0153] 11 Measurement camera (photographing means) 12 Vibration table (vibrating means) 14b Actuator (scanning means) 15 Locus change measurement means (measurement means) 100 Blur evaluation device

Claims

1. A blur evaluation device for evaluating the blur of photographing means having an anti-shake function, comprising: scanning means for scanning a subject in a first direction; vibrating means for vibrating the photographing means, which photographs the subject being scanned by the scanning means with the anti-shake function turned on, in a second direction different from the first direction; measuring means for measuring the amount of blur of the image based on a change in a locus related to the second direction in the image photographed by the photographing means. The blur evaluation device is characterized by having the above.

2. The subject is a point object, and the measuring means obtains the amount of blur based on a locus waveform obtained from the center-of-gravity locus of the point object in the image. The blur evaluation device according to claim 1 is characterized by this.

3. The measuring means divides the locus waveform into a plurality of calculation regions, and obtains the amount of blur for each of the plurality of calculation regions. The blur evaluation device according to claim 2 is characterized by this.

4. The measuring means obtains the intervals of the plurality of calculation regions based on the exposure time of the photographing means. The blur evaluation device according to claim 3 is characterized by this.

5. The measuring means obtains the amount of blur by moving the plurality of calculation regions. The blur evaluation device according to claim 3 or 4 is characterized by this.

6. The blur evaluation device according to any one of claims 1 to 5 further comprises measurement synchronization means for synchronizing the photographing by the photographing means and the scanning by the scanning means.

7. The measurement synchronization means controls the scanning means based on the photographing timing of the photographing means. The blur evaluation device according to claim 6 is characterized by this.

8. The measurement synchronization means controls the photographing of the photographing means in synchronization with the position of the subject scanned by the scanning means. The blur evaluation device according to claim 6 is characterized by this.

9. The subject is a collimated light source. The blur evaluation device according to any one of claims 1 to 8 is characterized by this.

10. The scanning means rotates and scans the subject around the photographing means. The blur evaluation device according to claim 9 is characterized by this.

11. The blur evaluation device according to claim 10 further comprises rotation control means for changing the rotation radius of the scanning means.

12. The vibrating means can vibrate the photographing means in a plurality of second directions, The blur evaluation device according to claim 1, wherein the first direction is different from any of the plurality of second directions.

13. The blur evaluation device according to claim 12, wherein the first direction is a direction orthogonal to the vibration axis of the combined direction of the plurality of second directions.

14. The subject is a chart, The blur evaluation device according to any one of claims 1 to 13, wherein measurement is performed by a measurement camera as the photographing means with the width of a boundary determined based on an image obtained by photographing the chart by a reference camera.

15. The boundary changes from a first color to a second color, The blur evaluation device according to claim 14, wherein the chart is capable of changing the distance from the first color to the second color.

16. Blur amount calculation means for calculating a blur amount from an image of the reference camera, Detection means for detecting the width of the boundary when the blur amount of the reference camera reaches a predetermined value, Changing means for changing the boundary width of the chart based on the result of detection by the detection means, and further comprising: The blur evaluation device according to claim 14 or 15, wherein measurement is performed by a measurement camera using the chart changed by the changing means.

17. The blur evaluation device according to any one of claims 14 to 16, wherein the reference camera photographs the chart simultaneously with the measurement camera.

18. The blur evaluation device according to any one of claims 14 to 16, wherein the reference camera photographs the chart at a timing different from that of the measurement camera.

19. The blur evaluation device according to any one of claims 14 to 18, wherein the width of the boundary at any location on the chart can be changed.

20. A blur evaluation method for evaluating the blur of photographing means having an anti-shake function, Scanning a subject that is a point object in a first direction using scanning means; Photographing the subject being scanned by the scanning means with the anti-shake function turned on using the photographing means; Vibrating the photographing means in a second direction different from the first direction; Measuring a blur amount of the image based on a locus change related to the second direction in the image photographed by the photographing means.

21. A method for manufacturing an imaging means, comprising: a step of evaluating an anti-shake function of the imaging means using the shake evaluation method according to claim 20. A method for manufacturing an imaging means, characterized by comprising the step.

22. A program characterized by causing a computer to execute the shake evaluation method according to claim 20.

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