Abstract:
An image blur prevention apparatus adapted to a camera having an exposure portion, includes a first image blur detecting device that detects an image blur state of the camera, a second image blur detecting device that detects an image blur state of an optical image of the camera, and outputs a detection signal, and a determining portion that determines a photographing operation state of the camera. A calculating device, having a first calculation program and a second calculation program, selects one calculation program from among the first and second calculating programs based on a determination result of the determining portion and based on the detection signal of the second image blur detection device, and calculates a predicted blur signal in accordance with the selected calculation program. An image blur prevention device then performs an image blur prevention operation based on the detection signal of the first image blur detecting device and the predicted blur signal calculated by the calculating device, during a light exposing operation onto the exposure portion of the camera.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an image blur preventing apparatus for preventing image blur caused by hand vibration or the like in a camera, an optical apparatus or the like. 
     2. Related Background Art 
     The construction of the essential portions of an example of a camera provided with a fluctuation preventing system is shown in FIG. 21 of the accompanying drawings. In FIG. 21, a CPU  301  in a camera body  300  governs the control of the whole camera, focus control and fluctuation preventing control. Focus control and fluctuation preventing control will hereinafter be described briefly. 
     The case of focus control will first be described. Incident light from an object entering through a focusing lens  306 , a main photographing lens  305  and a fluctuation correction lens  304  is imaged on an image sensor  303  through a main mirror  307 , an AF sub-mirror  308  and a field lens  309 . The image formed on this image sensor  303  comprises two kinds of light beams passing through the different optical paths of the photographing optical system  305  by the conventional so-called pupil division system, and the defocus amount relative to a film surface  311  is detected from the amount of relative deviation of these two images on the image sensor  303 , and the focusing lens  306  is moved in the direction of the optical axis thereof in accordance with this defocus amount to thereby realize focus control. 
     Description will now be made of a case where fluctuation correction control is effected. An image blur correction amount is calculated from the combination of a fluctuation signal output from a mechanical sensor  302  such as an angular speed sensor such as a vibration gyro or other angular acceleration sensor (or a linear acceleration sensor) and an image blur signal output found from the amount of movement of the image data formed on the image sensor  303  through the aforementioned respective optical systems during different times, and on the basis of this image blur correction amount, the correction lens  304  is actually driven in real time as indicated by the arrow to thereby prevent the blur of an image on the film surface  311  (an image formed when the mirror  307  and the sub-mirror  308  are retracted in actual exposure). 
     In the case of the above-described example of the prior art, however, it is possible to introduce the data of the object image into the image sensor  303  through the intermediary of the mirror  307  and the sub-mirror  308  before exposure, but during exposure, the mirror  307  and the sub-mirror  308  are retracted as a matter of course and therefore, the output from the image sensor  303  becomes unusable. As a countermeasure for this, as disclosed in Japanese Patent Application Laid-Open No. 4-163534, there is a method of simply detecting the image blur speed immediately before exposure is started, and simply linearly approximating the blur at that speed. Although this method is effective when the movement of the object or the vibration of a photographer is taking place at an equal speed, the effect of this method cannot be said to be sufficient when fluctuation is taking place at a predetermined cycle or when the shutter speed of a camera used is low. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a blur preventing control apparatus which can calculate an optimum predicted blur waveform for image blur control during exposure by the operational state or the state of fluctuation of a camera. 
     One aspect of the invention is an image blur preventing apparatus applicable to a camera which has an image blur detecting device for detecting an image blur state, a predicting portion for predicting the image blur state after a predetermined point of time on the basis of the detection output of the image blur detecting device at the point of time, and forming a predicted image blur signal corresponding to the image blur state, an image blur preventing device for performing an image blur preventing operation in accordance with the predicted image blur signal obtained by the predicting portion, and a changing portion for changing the manner of the prediction by the predicting portion in accordance with the photographing operation state of the camera, whereby optimum prediction is effected in accordance with the state of the camera. 
     Another aspect of the invention is a signal forming apparatus for use for the image blur prevention of a camera and for forming a signal corresponding to an image blur state which has an image blur detecting device for detecting an image blur state, a predicting portion for predicting the image blur state after a predetermined point of time on the basis of the detection output of the image blur detecting device at the predetermined point of time, and forming a predicted image blur signal corresponding to the image blur state, and a changing portion for changing the manner of the prediction by the predicting portion in accordance with the photographing operation state of the camera, or a camera having such a signal forming apparatus, whereby optimum prediction is effected in accordance with the state of the camera. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing the construction of the essential portions of a camera according to a first embodiment of the present invention. 
     FIG. 2 is a flowchart showing a series of operations of the camera according to the first embodiment of the present invention. 
     FIG. 3 is a flowchart showing the continuation of the operations of FIG.  2 . 
     FIG. 4 is a circuit diagram showing a filter circuit disposed at the rear stage when a vibration gyro is used as an example of a fluctuation sensor shown in FIG.  1 . 
     FIG. 5 is a perspective view showing an example of the construction of a fluctuation correction system according to the first embodiment of the present invention. 
     FIG. 6 is a flowchart showing the sampling timer interrupted processing in the first embodiment of the present invention. 
     FIG. 7 is a flowchart showing the operation during high-pass calculation in the first; embodiment of the present invention. 
     FIGS. 8A and 8B illustrate the calculating methods during high-pass calculation and during integral calculation in the first embodiment of the present invention. 
     FIG. 9 shows an optical system for effecting defocus detection by a pupil division system in the first embodiment of the present invention. 
     FIGS. 10A,  10 B,  10 C,  10 D and  10 E show the defocus states in each direction obtained when the optical system of FIG. 9 is used. 
     FIG. 11 is a flowchart showing the detailed operation during the defocus detection shown in FIG.  2 . 
     FIG. 12 is a flowchart showing the continuation of the operation of FIG.  11 . 
     FIG. 13 is a flowchart showing the operation during the fluctuation detection shown in FIG.  3 . 
     FIG. 14 is a flowchart showing the continuation of the operation of FIG.  13 . 
     FIG. 15 is a flowchart showing the operation of predicted fluctuation correction data calculation shown in FIG.  3 . 
     FIG. 16 is a flowchart showing the continuation of the operation of FIG.  15 . 
     FIG. 17 aids the illustration of the predicted fluctuation correction data calculation of FIGS. 15 and 16. 
     FIG. 18 also aids the illustration of the predicted fluctuation correction data calculation of FIGS. 15 and 16. 
     FIG. 19 is a flowchart showing the operation of the predicted fluctuation correction data calculation of a camera according to a second embodiment of the present invention. 
     FIG. 20 is a flowchart showing the continuation of the operation of FIG.  19 . 
     FIG. 21 shows the construction of the essential portions of a camera provided with a fluctuation preventing system according to the prior art. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention will hereinafter be described in detail with respect to some embodiments thereof shown in the drawings. 
     FIG. 1 is a block diagram showing the construction of the control circuit system of a camera provided with a fluctuation preventing apparatus according to a first embodiment of the present invention. 
     In FIG. 1, the reference numeral  1  designates a whole control circuit which governs the sequence of the whole, focus control and fluctuation correction control. The fluctuation output of a fluctuation sensor  4  (detection in a pitch direction) comprising a mechanical sensor such as a vibration gyro is inputted to an A/D converter  2  through a filter circuit  5 , whereby it is converted into digital data and introduced into the whole control circuit  1 . Likewise, the output of a fluctuation sensor  6  (detection in a yaw direction) is inputted to the A/D converter  2  through a filter circuit  7 , and is introduced as digital data into the whole control circuit  1 . The whole control circuit  1  has therein a sampling timer  8  for setting the timing for introducing the data from the A/D converter  2  at each predetermined time and effecting fluctuation correction calculation, and outputs the result of the fluctuation correction calculation to a D/A converter  3  on the basis of this timing. The D/A converter  3  outputs an analog voltage proportional to the input data, and this output voltage is outputted to a fluctuation correction system driving circuit  13 , and the supply of a predetermined electric current to a correction system actuator coil  14  is effected and thus, a correction lens  23  is driven in a direction indicated by the arrow. 
     On the other hand, the incident light from an object enters a main mirror  24  through a focusing lens  21 , a main photographing lens  22  and a correction lens  23 , and part of the incident light passing through the half mirror portion thereof is reflected by an AF sub-mirror  25  and finally enters an image sensor  16  through a field lens  26 . An image sensor  16  is driven from the whole control circuit  1  through a sensor driving circuit  15 , and the output signal thereof is sequentially input to a video signal processing circuit  17 . The signal output from this video signal processing circuit  17  is converted into digital data by an A/D converter  18 , the output of which is output to the whole control circuit  1 , a frame memory  19  and a movement vector detecting circuit  20 . 
     Accordingly, as will be described later, in the case of focus control, the image data from the A/D converter  18  is directly introduced into the whole control circuit  1 , and a defocus amount is calculated from the amount of deviation of two images by light beams passing through two different routes in the photographing optical system, and or the basis of this defocus amount, electric power is supplied to a focus motor  12  by a motor driving circuit  11  to thereby drive the focusing lens  21 , thus effecting focus adjustment. 
     Also, in the case of fluctuation detection, as will be described later, a fluctuation vector is calculated from the relation between the output from the A/D converter  18  and the output of the frame memory  19 , i.e., the correlation between the image data at different timings, by the movement vector detecting circuit  20 . This fluctuation vector is output to the D/A converter  3  in combination with the aforementioned fluctuation sensor output, and the fluctuation correction lens  23  is likewise driven. 
     Also, the timing control of a shutter curtain  33  (comprised of a leading curtain and a trailing curtain) is effected by the control signal from the whole control circuit  1  through a shutter driving circuit  35 , and the supply of electric power to a motor  30  is effected by the control signal from the whole control circuit  1  through a motor driving circuit  29 , and the driving of the main mirror  24  and the sub-mirror  25 , film feeding, etc. are executed. Also, the incident light from the object totally reflected by the main mirror  24  is directed to a photographer through a finder optical system comprised of a prism  27  and an eyepiece  28 . 
     In addition, this camera is provided with mode setting means  10  for setting the photographing mode, etc., switches  31  (SW 1 ) and  32  (SW 2 ) actuated upon the operation of the release button of the camera, and focal length detecting means  34  for detecting the focal length of the photographing lens  22 . 
     The actual operation of the camera will now be described with reference chiefly to a main flowchart shown in FIGS. 2 and 3. 
     In FIG. 2, first at a step # 100 , whether the switch SW 1  of the camera designated by  31  in FIG. 1 is ON is judged, and if it is ON, shift is made to a step # 101 , where the actuation of the fluctuation sensors  4  and  6  of mechanical construction is started. 
     Here, the specific construction of the fluctuation sensor  4  and filter circuit  5  (or the fluctuation sensor  6  and filter circuit  7 ) of FIG. 1 will be described with reference to the circuit diagram of FIG.  4 . 
     FIG. 4 is a diagram when a conventional vibration gyro  40  is used as the fluctuation sensor, and a vibration is resonating in the vicinity of the resonance frequency thereof through a synchronized phase detecting circuit  41  and a driving circuit  42 . A fluctuation angular speed signal proportional to Corioli&#39;s force modulated at that resonance frequency is detected by the synchronized phase detecting circuit  41 , whereby only an ordinary angular speed signal is taken out. Usually, in the output after this detection of the synchronized phase, there is an offset voltage (a null voltage) even in the state of angular speed  0 , and in order to remove this unnecessary DC voltage component, design is made such that an analog high-pass filter circuit comprising an OP amplifier  43 , a capacitor  44  and resistors  45  to  47  cuts components below a predetermined frequency (a cut-off frequency determined by the capacitor  44  and the resistor  45 ) and only the remaining signal component is input to the A/D converter  2  of FIG.  1 . 
     Turning back to FIG. 2, at a step # 102 , the supply of electric power to the fluctuation correction system denoted by  13  and  14  in FIG. 1 is effected to thereby start the driving of the correction lens  23 , and this specific construction will now be described on the basis of the mechanical construction of FIG.  5 . 
     In FIG. 5, the reference numeral  50  designates a correction lens system corresponding to the correction lens  23  of FIG.  1  and freely movable on a plane perpendicular to the optical axis thereof by a method as will be described later. This correction lens system  50 , for movement in the direction of the x-axis indicated in FIG. 5, is freely operated by the amount and direction of electric current supplied to a winding coil  52  in a magnetic circuit unit comprised of a magnetic member  51  comprising a magnet and a yoke portion and the winding coil  52 ; likewise, for movement in the direction of the y-axis, the system is operated by the combination of a magnetic member  53  comprising a magnet and a yoke portion and a magnetic circuit unit comprised of a winding coil  54 . 
     On the other hand, design is made such that the amount of movement of such a correction lens system  50  relative to a lens barrel support frame  55  is detected in non-contact by the combination of IREDs  56  and  57  movable with the correction lens system  50  and PSDs  58  and  59  fixedly mounted on the lens barrel support frame. The reference numeral  60  denotes a mechanical lock mechanism for mechanically locking the movement of the correction system, and depending on the direction of supply of electric current to a magnet annexed to it, the projected portion  61  of the mechanical lock member jumps into or out of a depressed portion  62  movable with the correction lens system  50 , thereby effecting lock/unlock. 
     The reference numeral  63  designates a support ball as a door stop for regulating the movement of the shift correction lens system  50  in the direction of inclination. 
     Next, at the step # 103  of FIG. 2, the time counting operation of a sampling timer  8  in the whole control circuit  1  of FIG. 1 is started to sampling-control the correction system at predetermined time intervals on the basis of the above-described fluctuation sensor output. 
     Here, the interrupted processing of the sampling timer  8  will be described with reference to the flowchart of FIG.  6 . 
     As regards the interrupted processing of FIG. 6, each time the sampling timer  8  counts a predetermined time ts, the operation of the main flowcharts of FIGS. 2 and 3 is temporarily interrupted and the processing is preferentially executed, and the signal processing of the fluctuation sensors  4  and  6  of FIG.  1  and the driving control of the correction lens  23  are effected. 
     First, at a step # 150 , the A/D conversion of the output of the fluctuation sensor  4  (and  6 ) after the passage thereof through the filter circuit  5  (and  7 ) is started through the A/D converter  2 , and when it is detected at the next step # 151  that the conversion has been completed, the result of the conversion is transferred to an internal A register at the next step # 152 . At the next step # 153 , high-pass calculation for removing in the fashion of digital calculation the DC component of the data corresponding to this fluctuation sensor output which cannot be taken out by the analog high-pass filter shown in FIG. 4 is executed. 
     The manner of this calculation will now be described with reference to the flowchart of FIG.  7 . First, at a step # 170 , the value of the A register as input data is once transferred to a K register and next, at steps # 171  to # 173 , as shown in FIG. 8A, the values of coefficient values b 1 , a 0  and a 1  determined from the constants of an analog high-pass filter by conventional S-Z conversion are set in internal B 1 , A 0  and A 1  registers, respectively. Further, at a step # 174 , the value of work data of which the value has been set at the last sampling timing is transferred to a W register, and at the next step # 175 , the result of the multiplication of the B 1  register by the W 1  register is subtracted from the value of the K register in which the above-mentioned input data value is set, and the result thereof is set in a W 0  register. 
     At the next step # 176 , the value of the multiplication of the W 0  register by the A 0  register and the value of the multiplication of the W 1  register by the A 1  register are added, and the result thereof is set in a U register, and at the next step # 177 , the value of this U register is output as the final high-pass calculation result. Lastly, at a step # 178 , the value of W 0  is stored as the work data during the next sampling timing in an internal memory and this calculation subroutine is ended. 
     The result of such execution of the high pass calculation is once set in the A register at the step # 154  of FIG. 6, and now at a step # 155 , integral calculation for converting an angular speed signal into an angular displacement signal is effected. A specific method of integral calculation is entirely similar to the above-described flowchart of FIG.  7 . However, the coefficients set at the steps # 171  to # 173  of FIG. 7 are values found from an analog low-pass filter shown in FIG. 8B by S-Z conversion. Accordingly, detailed description is omitted here, and the final output after the integral calculation is again set in the A register at the step # 156  of FIG.  6 . 
     At the next step # 157 , the correction movement amount D is calculated from the content of the A register for this integral calculation result on the basis of a function f(A) (set by the integrated output and the map information of the zoom/focus position) with the degree of sensitivity of the correction system (the correction movement amount of the correction lens  23  relative to the detected angle is changed in accordance with the photographing system zoom and focus position) actually taken into account. 
     At the next step # 158 , whether a flag SHON indicating that an exposure sequence (the shutter opening-closing control of the camera) is actually going on is 1 is judged, and now the exposure sequence is not going on and the state of this flag is 0 and therefore, at a step # 159 , a fluctuation predicted data counter P used in the exposure sequence which will be described later is cleared to 0. Then, at a step # 160 , the fluctuation correction data D obtained at the step # 157  is output to the D/A converter  3 . As the result, an electric current based on the correction data is supplied to the actuator coil  14  through the fluctuation correction system driving circuit  13  and therefore, the correction lens  23  is correction-moved on the basis of a fluctuation signal. 
     Turning back again to the flowchart of FIG. 2, at a step # 104 , the luminance of the object is measured by a photometry circuit, not shown, and from this photometry value, the actual shutter speed and aperture value are determined by AE calculation. At the next steps # 105  to # 107 , the detection of the defocus amount for effecting the focus adjustment of the object is executed by the image sensor  16  of FIG. 1; at the step # 105 , accumulation control to the image sensor  16  is effected, at the step # 106 , the sensor image is retrieved, and at the step # 107 , the actual defocus amount calculation is effected. 
     Here, the optical system and sensor construction for the specific defocus detection will be described with reference to FIGS. 9 and 10A to  10 E. 
     FIG. 9 shows an optical system for effecting defocus detection of the pupil division type utilizing the amount of relative deviation of light beams from the main object passing through the different areas of the photographing lens system on sensors A and B, and the defocus state of a pattern in a lateral direction is calculated from the amount of correlation (the relative relation between a and b when sensor pixels are deviated relative to one another) to the luminance information of a sensor group a (comprised of pixels a 0 , . . . , a n ) and a sensor group b (comprised of pixels b 0 , . . . , b n ) shown in FIGS. 10B and 10C, and the defocus state of a pattern in a vertical direction is calculated from the value of the amount of correlation to the luminance information of a sensor group c (comprised of pixels c 0 , . . . , C n ) and a sensor group d (comprised of pixels d 0 , . . . , d n ) shown in FIGS. 10D and 10E. 
     The detailed method of defocus detection shown at the steps # 105  to # 107  will now be described with reference to the flowcharts of FIGS. 11 and 12. 
     First, at a step # 180 , the accumulating operation to the image sensor  16  (corresponding to the sensor groups a to d of FIGS. 10B to  10 E) is started through the sensor driving circuit  15 . At the next step # 181 , whether the accumulation in the sensor has been completed is judged, and at a point of time whereat the accumulation has been completed, advance is made to a step # 182 , where the accumulating operation is stopped. At the next steps # 183  to # 186 , the accumulated pixel data of the sensor group a is read out. That is, at the step # 183 , a counter i for indicating each pixel number is reset to 0, and at the next step # 184 , the luminance data of each pixel actually passed through the video signal processing circuit  17  is converted into digital data through the A/D converter  18 , and the digital data is stored in an internal memory Ai. At the next step # 185 , whether the value of the counter i is equal to n is judged, and if it is equal to n, it is judged that the reading-out of all pixels of the sensor group has been terminated, but if it is not equal to n, shift is made to the step # 186 , where the value of the counter i is counted up by 1, and again shift is made to the step # 184 , where the A/D conversion of the next sensor pixel data is effected. 
     As described above, the image data reading-out operation of the sensor group a is performed, and to the sensor group b as well, the image data reading-out operation is quite likewise performed at steps # 187  to # 190 . 
     A method of calculating the defocus amount from the correlative calculation of the pixel data of the sensor groups a and b will now be described with reference to the steps # 191  to # 199  of FIG.  12 . 
     First, at the step # 191 , −m (m&gt;0) is set as an initial value in an internal counter K for actually setting the amount of relative image deviation of the sensor groups a and b, and at the next step # 192 , a predetermined initial value is substituted for Ud as the comparative data of correlative calculation result. At the step # 193 , data A is deviated by K relative to data B, and then the differential absolute value of each corresponding pixel is calculated from Aα+K to Aβ+K for A and from Bα to Bβ for B, and the result is stored as U(K) in memories Ai and Bi storing therein the pixel data of the sensor groups a and b. 
     Next, at the step # 194 , the value of U(K) is compared with the comparative data Ud, and if the value of U(K) is smaller, the value of K is stored in an internal memory d at the next step # 195 , and at the subsequent step # 196 , the value of U(K) is substituted for the comparative data Ud. Then, at the step # 197 , whether the value of the counter K is equal to +m is judged, and if it is not yet equal to +m, the value of the counter K is counted up by 1 at the step # 198 , and again shift is made to the step # 192 , where correlative calculation based on the new value of K is executed. 
     Finally, at the step # 197 , the correlative calculation is completed at a point of time whereat the value of K has become equal to +m, and a defocus amount D R  calculated from a function D R (d) on the basis of the value of d storing therein the value of K when the degree of correlation is greatest (the value of U(K) becomes smallest) is output, and this detecting operation is completed. 
     Turning back again to FIG. 2, when the defocus detecting operation is completed as described above, at the next step # 108 , whether the lens is in focus is judged, and if it is not in focus, shift is made to a step # 109 , where the supply of electric power to the focus motor  12  is effected through the focus motor driving circuit  11  of FIG. 1, thereby driving the focusing lens  21  by the defocus amount D R . Thereafter, the aforedescribed defocus detection of the steps # 105  to # 107  is again effected, and when the in-focus state is confirmed at the step # 108 , focus driving is stopped at a step # 110 , whereby focus control is completed. 
     In the foregoing, description has been made of only the sensor groups a and b, but what has been described above also holds true of the sensor groups c and d and therefore, these sensor groups need not be described here. 
     At steps # 111  to # 114  shown in FIG. 3, blur detection is effected on the basis of the image data from the image sensor  16 . That is, at the step # 111 , the accumulation control of the sensor is effected, at the step # 112 , the sensor image data is retrieved, at the step # 113 , correlative calculation with the frame memory data in which the last image data is stored is effected, and at the step # 114 , the final movement vector amount is found; the detailed operation thereof will hereinafter be described with reference to the flowcharts of FIGS. 13 and 14. 
     First, at a step # 200 , the accumulation control of the image sensor  16  is started through the sensor driving circuit  15 , and the detection of the object image is effected through the optical systems  21 ,  22 ,  23 , the mirrors  24 ,  25  and the AF optical system  26  shown in FIG.  1 . Then, at the next step # 201 , whether the accumulation has been completed is judged; the accumulation is regarded as having been completed by the detection of the fact that a predetermined level has been reached. At the next step # 202 , the sensor driving (accumulation) operation is stopped. 
     At steps # 203  to # 206 , the operation of reading out the pixel data of the sensor group a shown in FIG. 10B successively is started. First, at the step # 203 , a counter i for indicating each pixel number is reset to 0, and at the next step # 204 , the luminance data of each pixel actually passed through the video signal processing circuit  17  is converted into digital data through the A/D converter  18 , and the digital data is stored in an internal memory Si. At the next step # 205 , whether the value of the counter i is equal to n is judged, and if it is not equal to n, shift is made to a step # 206 , where the value of the counter i is counted up by 1, and again at the step # 204 , the sensor pixel data is retrieved. Also, at a point of time whereat the value of the counter i has become equal to n at the step # 205 , the retrieval (the conversion into digital data) of all pixel data of the sensor group a is regarded as having been completed, and shift is made to a step # 207 , where the image data during the last sampling is transferred from the frame memory  19  to an internal memory Ti. At steps # 208  to # 210 , the value of the counter i changes from 0 to n, and the transfer of all pixel data is effected. 
     Description will now be made of a method of detecting the movement of the actual object image from the correlation between two image data of the sensor group a spaced apart by a predetermined time from each other. 
     First, at the step # 211  of FIG. 14, −m (m&gt;0) is set as an initial value in the internal counter K for setting the relative image deviation amount of the image data Si of the sensor group actually retrieved during the current sampling and the image data Ti of the sensor group b retrieved during the last sampling, and at the next step # 212 , a predetermined initial value is substituted for Ms as the comparative data of correlative calculation result. At the next step # 213 , data S is deviated by K relative to data T between the memories Si and Ti storing therein the pixel data of the sensor group a during the current sampling and during the last sampling, whereafter the sum of the differential absolute values of the respective corresponding pixels is calculated from Sα+K to Sβ+K for S, and from Tα to Tβ for T, and the result thereof is stored as M(K). 
     Next, at a step # 214 , the value of M(K) is compared with comparative data Ms, and if the value of M(K) is smaller, at the next step # 215 , the value of K is stored in an internal memory S, and at the next step # 216 , the value of M(K) is substituted for the comparative data Ms. At the next step # 217 , whether the value of the counter K is equal to +m is judged, and if it is not yet equal to +m, at a step # 218 , the value of the counter K is counted up by 1, and again shift is made to the step # 212 , where correlative calculation based on the new value of K is effected. 
     Finally, at a point of time whereat the value of K has become equal to +m at the step # 217 , the correlative calculation is completed, and the value of S storing therein the value of K when the degree of correlation is greatest (the value of M(K) becomes smallest) is found. This value of S represents the amount of movement of the object image on the sensor group a when a predetermined time interval is given, that is, is indicative of the x direction (yaw direction) component of the movement vector speed of the image. 
     Accordingly, at a step # 219 , the blur speed V x  in the x direction is calculated from a function V x (S) with the value of S as a variable. 
     Subsequently, at a step # 220 , a fluctuation speed V x−1  determined at the last sampling timing is read out, and at a step # 221 , a fluctuation speed V x−n  determined at sampling timing n times before is read out, whereafter at a step # 222 , the average value of the fluctuation speeds at total (n+1) times from V x  to V x−n  at n times before is calculated as V x , and at a step # 223 , the average value of the image blur movement vectors found at the final current sampling is set in a memory M(t), and lastly at a step # 224 , the current image data is stored in the frame memory  19  for the next fluctuation speed detection. 
     Blur detection in the y direction can be accomplished by a method entirely similar to that in the processing in the x direction by the use of the sensor group c or d and therefore, need not be described here. 
     Turning back to FIG. 3, at a step # 115 , whether the switch SW 2  of the camera is ON is judged, and if it is still OFF, at a step # 116 , whether the switch SW 1  is ON is judged, and if it is ON, shift is again made to the step # 111 , where the blur detecting operation is performed, but if the switch SW 1  is OFF, return is made to the step # 100  which is the START position. 
     On the other hand, if at the step # 115 , the switch SW 2  (the switch  32  of FIG. 1) is ON, the photographer is regarded as having performed the shutter release operation and shift is made to a step # 117 , where calculation for calculating predicted fluctuation data during exposure on the basis of the fluctuation data of the above-described image sensor  16  is started. 
     Here, the actual predicted fluctuation correction data calculation will be described with reference to the flowcharts of FIGS. 15 and 16. 
     First, at a step # 230 , whether the photographing mode of the mode setting means  10  of the camera body is the panning mode (a mode in which an object moving at a constant speed is photographed while the camera side is actually moved at the same speed as if the main object was made stationary and the back ground was moved) which is one of special photographing modes is judged, and if this mode is selected, shift is made to a step # 233 , where the value of the image blur movement vector speed M(t) detected by the aforedescribed method is set in an internal register A. 
     At the next step # 234 , an address counter P for storing a predicted fluctuation waveform in a memory is reset to 0, and at the subsequent step # 235 , the value of the image blur movement vector speed in the internal register A, the sampling interval ts when the correction system is actually controlled during exposure, and the result of the multiplication of all values of the address counter P are set in an internal memory g(P). This creates a predicted fluctuation waveform which increases/decreases monotonously (a predetermined inclination) on the basis of the average image blur movement speed immediately before the switch SW 2  becomes ON. At the next step # 236 , the value of P is counted up by 1, and at the subsequent step # 237 , whether the value of P exceeds a predetermined value P MAX  is judged, and if it does not exceed the predetermined value P MAX , shift is again made to the step # 235 , where predicted data corresponding to the value of the next P is set in the memory g(P). At a point of time whereat the value of P has exceeded P MAX , this operation is ended. 
     It is FIG. 17 that shows the predicted fluctuation waveform prepared by such a method, and the inclination of displacement is M(t). This waveform data is added to the output of the mechanical fluctuation sensor in accordance with the actual shutter release timing as will be described later, and the correction lens  23  is driven in accordance with the added output. 
     On the other hand, if at the step # 230 , the photographing mode is not the panning mode, which is one of a number of special modes, at the next step # 231 , whether the photographing shutter speed determined by the photometry and AE calculation of the step # 104  of FIG. 2 is longer than a predetermined shutter speed Tsha is judged, and if this is shorter than the predetermined shutter speed Tsha, the operations of the above-described steps # 233  to # 237  are executed to thereby make a simple predicted fluctuation waveform in which the displacement output linearly changes. This is due to the fact that the object fluctuation or the like can be sufficiently corrected in terms of probability even if the predicted waveform when the shutter speed is short to a certain degree is not especially made into a complicated waveform. 
     Also, if at the step # 231 , the photographing shutter speed is longer than the predetermined value Tsha, shift is made to a step # 232 , where whether the value of the focal length detecting means  34  of the photographing lens system of FIG. 1 is longer than a predetermined focal length fα is judged. If the focal length of the photographing lens is not longer than fα, it is judged that even if the shutter speed is long, sufficient object fluctuation correction can be accomplished even in the case of the above-described simple predicted fluctuation waveform because the focal length is short, and shift is made to the step # 233  and subsequent steps. 
     On the other hand, if at the step # 232 , the focal length of the photographing lens is longer than the predetermined value fα, the shutter speed used is also long and the focal length is also long and therefore, a sufficient fluctuation correction effect may not be obtained by a simple predicted fluctuation waveform, and a small degree of complication in the predicted fluctuation waveform becomes necessary. 
     The method in this case will hereinafter be described with reference to the flowchart of a step # 238  and subsequent steps. 
     First, at the step # 238 , the value of the image blur movement vector speed M(t) at the current point of time detected by the image sensor  16  by the use of the aforedescribed method is transferred to A register and at the same time, at steps # 239  and # 240 , the value of this A register is set as an initial value in internal memories MAX and MIN. At the next step # 241 , data address setting counters i and j are reset to 0, and at a step # 242 , the value of a memory M(t−i) (the values of M(t), M(t−1), M(t−2), . . . , M(t−m) are successively read out by a method which will be described later) is transferred to B register, and at a step # 243 , the value of this B register is compared with the internal memory MAX. If the value of B is not greater than the internal memory MAX, shift is directly made to a step # 246 , but if the value of B is greater than the internal memory MAX, at step # 244 , the value of B is first substituted for MAX, and the value of the data address counter i is set in an internal register E. 
     Also, at the step # 246 , the value of the B register is now compared with the internal memory MIN, and if this is not smaller than MIN, shift is directly made to a step # 248 , but if it is smaller than MIN, the value of B at a step # 247  is substituted for MIN. 
     Next, at the step # 248  of FIG. 16, whether the value of the B register is within a predetermined value range (−ΔV to +ΔV) and is substantially approximate to 0 is judged. If this value is not substantially approximate to 0, shift is directly made to a step # 251 , but if this value is substantially approximate to 0, at a step # 249 , the value of the data address setting counter i is set to T(j) (in the first case, T(0)), and at the next step # 250 , the value of j is counted up by 1. Subsequently, at a step # 251 , the value of the data address setting counter i is counted up by 1 to refer to the movement vector speed data before the current point of time, and at the next step # 252 , whether the value of i is greater than a predetermined value m is judged. If the value of i is not yet greater than the predetermined value m, it is judged that the reference to the image blur movement vector speed stored in the memory M(t−i) has not yet been completed, and shift is made to the step # 242 , but if the value of i is greater than m, it is judged that the reference to all memory M(t−i) data has been completed, and shift is made to a step # 253 . 
     If the average image movement speed of the memory M(t−i) is a waveform having a certain periodicity as shown in FIG. 18, the amplitude of the waveform is set in the internal memories MAX and MIN found by the above-described method, and the frequency thereof is found from two data count values T(0) and T(1) at which the movement vector speed becomes nearly 0, and the phase component thereof is found from the value of the data counter E which is the value of MAX. In fact, the above-mentioned waveform represents the movement speed of the image and therefore, if it is to be converted into a predicted fluctuation displacement waveform, it is necessary to delay the phase component thereof by 90°. 
     Accordingly, at the step # 253 , the periodic time F of the predicted sine waveform is calculated from the calculation of 
     
       
         2×( T (1) −T (0)), 
       
     
     and at the next step # 254 , the counter value of a predicted waveform storing memory is reset to 0, and at the subsequent step # 255 , a predicted fluctuation waveform is found from the following expression: 
     
       
         {(MAX+MIN)/2}sin 2π{( P+E )/ F},   
       
     
     and this value is stored in the internal memory g(P). At a step # 256 , the value of P is counted up by 1 for the next data setting, whereafter at a step # 257 , whether the value of this P is greater than a predetermined value P MAX  is judged. Accordingly, predicted fluctuation waveform data are successively stored until P becomes greater than P MAX . 
     At a point of time whereat the storing of all data has been completed, the predicted fluctuation correction data calculation as previously described is completed. 
     After the predicted fluctuation correction data calculation has been effected by the method as described above, the program again goes back to FIG. 3, and at a step # 118 , the main mirror  24  and the sub-mirror  25  for the AF optical system in FIG. 1 are driven. At this point of time, no object light enters the image sensor  16 . Next, at a step # 119 , an internal flag SHON indicating that the correction system is actually moved on the basis of the aforedescribed predicted fluctuation waveform is rendered to 1. 
     When the internal flag SHON becomes 1 as described above, in the sampling timer interrupted processing operation of FIG. 6 operating at each predetermined time period ts, shift is made from a step # 158  to a step # 161 , where the predicted fluctuation waveform data g(P) (at first, g(0)) found by the above-described method is set in an internal memory G, and at the next step # 162 , the value of this G is added to the value of the correction system driving data D calculated from the outputs of the fluctuation sensors  4  and  6  before the step # 157 , and is again set in D register. 
     At the next step # 163 , the value of this D is outputted through the D/A converter  3  and therefore, a coil current proportional to the value of this D register flows to the driving coil  14 , thus driving the correction lens  23  by a predetermined amount. Lastly, at a step # 164 , the value of the data address counter P is counted up by 1 for the next reading-out of the waveform data, and this interrupted processing operation is completed. 
     The correction optical system is actually driven by the object fluctuation predicted waveform found from the image sensor output before the start of exposure by the method as described above and the fluctuation sensor output, whereafter at the step # 120  of FIG. 3, the driving of the leading curtain of the shutter unit  33  is started through the shutter driving circuit  35  of FIG. 1, and at the next step # 122 , a timer for setting the shutter speed is started, whereafter whether this timer has reached a predetermined time Tsh corresponding to the set shutter speed is judged. When the predetermined time Tsh is counted, the driving of the shutter trailing curtain is now started at a step # 123 , and at the subsequent step # 124 , whether the feeding of the shutter trailing curtain has been completed is judged. 
     When at the step # 124 , the completion of the feeding of the shutter trailing curtain is detected, at the next step # 125 , the flag SHON is reset to 0 and thus, in the flowchart of FIG. 6, the addition of the predicted fluctuation data to the driving of the correction system is stopped. Lastly, at a step # 126 , the main mirror  24  and the AF sub-mirror are returned to their original states, whereafter at a step # 127 , a predetermined amount of film feeding is effected and the release sequence is completed. 
     Thus, in the above-described first embodiment, design is made such that, depending on the operative state of the camera, the predicted fluctuation waveform found from the image sensor is changed. 
     (Second Embodiment) 
     The operations of the main portions of a camera according to a second embodiment of the present invention will now be described with reference to the flowcharts of FIGS. 19 and 20. The other operations and electrical and mechanical constructions of the camera are similar to those of the first embodiment and therefore need not be described. 
     First, at a step # 260 , the high-pass calculation result (i.e., the fluctuation speed output) from the fluctuation sensor signal-processed by the sampling timer interrupted processing shown in FIG. 6 is transferred to the A register. At the next step # 261 , whether the value of this A register is within the range of a predetermined value −α to +α, i.e., within a predetermined speed range, is judged, and if it is within the predetermined speed range, it is judged that the photographer himself is trying ordinary photographing, and a step # 269  and subsequent steps are executed. 
     The operations of the step # 269  of FIG. 19 to the step # 288  of FIG. 20 are entirely the same as those of the step # 238  of FIG. 15 to the step # 257  of FIG. 16, and at these steps, predicted fluctuation waveform data at a predetermined cycle and during a predetermined fluctuation is calculated and stored. 
     On the other hand, if at the step # 261 , the fluctuation sensor output is a predetermined speed or higher, shift is made to a step # 262 , where the fluctuation sensor integral calculation result calculated in the flowchart of FIG. 6 is transferred to the B register. At the next step # 263 , if the value of this B register, i.e., the fluctuation displacement output, is within the range of predetermined values −β to +β, it is also judged that the photographer himself is trying ordinary photographing, and the step # 269  and subsequent steps are executed. 
     However, if the output of the B register is not within the range of −β to +β, both of the fluctuation speed and the fluctuation displacement exceed predetermined levels and in such case, the possibility of such photographing (for example, panning or the like) that the photographer himself is intentionally moving the camera is apparently high and therefore, the operations of the step # 264  and subsequent steps are executed. The operations of the steps # 264  to # 268  of FIG. 19 are entirely similar to those of the steps # 233  to # 237  of FIG. 15, and the fluctuation output during exposure may be simply predicted from the image sensor output immediately before exposure. 
     As described above, in the second embodiment, what kind of photographing the photographer is trying (whether he is stationary or is moving the camera) is judged from the output of the mechanical fluctuation sensor (capable of detecting only the fluctuation of the photographer himself) before exposure, and depending on the state thereof, the predicting method from the image sensor during exposure is changed. 
     According to each of the above-described embodiments, an optimum predicted fluctuation parameter corresponding to the photographing mode of the camera is calculated from the movement of the object image capable of being detected by the image sensor, and the object fluctuation during exposure can be predicted and controlled in accordance with that parameter and therefore, optimum fluctuation correction can be realized in any case. 
     Also, the output of a mechanical sensor for detecting only the ordinary fluctuation of the photographer himself, discretely from the image sensor, is used, whereby the predicted fluctuation parameter from the image sensor can be changed and the object fluctuation during the camera shutter exposure can be predicted and controlled in accordance with that parameter and therefore, a higher degree of, and more accurate fluctuation correction can be realized. 
     The present invention is not restricted to the constructions of these embodiments, but may assume any construction which can achieve the functions shown in the appended claims or the functions the embodiments have. 
     As described above, according to the above-described embodiments, the manner of predicting image blur by the image blur predicting means is changed in accordance with the state of the set shutter speed or the focal length state of the photographing lens and further, the state of whether the photographing mode is the panning mode, or the manner of predicting image blur by the image blur predicting means is changed in accordance with the output of the inertial fluctuation sensor immediately before the start of exposure, i.e., in accordance with whether, for example, the amount of fluctuation is greater than a predetermined value, and during the exposure of the camera, of the outputs of the inertial fluctuation sensor and the image blur predicting means, at least the output from the image blur predicting means is supplied to the image blur correcting means to thereby effect image blur correction and therefore, depending on the operative state and fluctuating state of the camera, it is possible to calculate an optimum predicted fluctuation waveform for the image blur control during exposure. 
     In each of the above-described embodiments, the present invention has been described with respect to an example in which it is applied to a single-lens reflex camera provided with a mirror adapted to be retracted from the photographing optical path during exposure, but the present invention is not restricted thereto. When as shown in FIG. 1, the fluctuation preventing system is made into a closed loop construction and fluctuation preventing control is effected in real time, oscillation readily occurs and proper fluctuation preventing control may sometimes become impossible, but if design is made such that in such a case, as in each of the above-described embodiments, image blur prediction is effected and on the basis thereof, fluctuation preventing control is effected during exposure or the like, more proper fluctuation preventing control will become possible. When such a point is taken into account, even if the present invention is applied to a camera which does not have a mirror adapted to be retracted from the photographing optical path during exposure, for example, a lens shutter camera or an electronic still camera or the like, the effect of the invention will be tremendous. Further, the present invention can be applied to other optical instruments or other apparatuses and furthermore, can also be applied as: a construction unit. 
     Also, the inertial fluctuation sensor may be any one capable of detecting fluctuation such as an angular acceleration meter, an acceleration, meter, an angular speedometer, a speedometer, an angular displacement meter or a displacement meter, or further one using a method of detecting the fluctuation itself of an image. 
     Also, the image blur correcting means is not restricted to the shift optical system as shown in FIG. 5 for moving an optical member in a plane perpendicular to the optical axis, but may be light beam changing means such as a variable vertical angle prism or one for moving the photographing surface in an image field perpendicular to the optical axis. 
     Further, the present invention may be of a construction in which the above-described embodiments or the techniques thereof are suitably combined together. 
     The individual components shown in a schematic or block form in the drawings are all well known in the camera art and their specific construction and operation are not critical to the operation or best mode for carrying out the invention. 
     While the present invention has been described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not restricted to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.