Abstract:
Provided is an unintentional hand movement canceling device including: a zoom detection means detecting a value corresponding to a zoom magnification; a swing detection means detecting a swing of an image; and a correction quantity generating means generating a correction quantity to correct the swing of an image based on a swing quantity detected by the swing detection means and a value corresponding to a zoom magnification detected by the zoom detection means, the correction quantity having a variable characteristic of a non-corrected residue percent at a frequency of the swing, wherein the correction quantity generating means varies a characteristic of the non-corrected residue percent at the frequency of the swing depending on a value corresponding to a zoom magnification detected by the zoom detection means.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to an unintentional hand movement canceling device installed in, for example a video camera and a digital camera. 
   2. Description of the Related Art 
   Since a video camera is in many cases used in hand-held shooting, an unintentional hand movement has been easy to occur in the shooting, therefore, generally, a video camera is equipped with an unintentional hand movement canceling device. 
   On the other hand, in the shooting, the video camera is, in many cases, subjected to a panning operation (a camera is moved in a direction, left or right) and a tilting operation (a camera is moved in a direction, upward or downward). If cancellation of unintentional hand movement is conducted by the unintentional hand movement canceling device during a panning operation or tilt operation, a phenomenon that a screen image does not move in an intentional direction occurs (hereinafter referred to as a sticking phenomenon). 
   Hence, in order to reduce a sticking phenomenon to occur during a panning operation or a tilting operation, a proposal has been offered on an unintentional hand movement canceling device performing a correcting control specially designed for the panning operation and tilting operation when the panning operation or tilting operation is detected. 
   For example, in Japanese Patent Application Laid-Open No. 8-331430, a construction is proposed in which a correction quantity is attenuated and a frequency characteristic of the correction quantity is varied according to a detection state of a panning operation or a tilting operation to thereby decrease the sticking phenomenon. 
   Since it is difficult to exactly discriminate a panning operation or a tilting operation from an unintentional hand movement, the sticking phenomenon occurs despite the measure to be taken. Especially, in an optical wide end with a low zoom magnification, a motion of screen image is comparatively small in both of the panning operation or tilt operation; therefore, a cancellation of unintentional hand movement is easily applied and a sticking phenomenon is conspicuously revealed. In addition, at an optical wide end, since a motion of a screen image is comparatively small even in a panning operation or a tilting operation, a change in a screen image becomes large when a state where an unintentional hand movement is canceled is transitioned to a state where an unintentional hand movement is not canceled if the unintentional hand movement is canceled at an initial stage of a panning operation or a tilting operation; therefore, there has occurred a problem that a strange feeling conspicuously appears at the optical wide end in a panning operation or a tilting operation. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to eliminate a conspicuously strange feeling in a panning operation and a tilting operation at the optical wide end even in a case where correct detection of a panning or tilting state is difficult. 
   A first unintentional hand movement canceling device according to the invention includes: a zoom detection means detecting a value corresponding to a zoom magnification; swing detection means detecting a swing of an image; and a correction quantity generating means generating a correction quantity to correct the swing of an image based on a swing quantity detected by the swing detection means and a value corresponding to a zoom magnification detected by the zoom detection means, the correction quantity having a variable characteristic of a non-corrected residue percent at a frequency of the swing, wherein the correction quantity generating means varies a characteristic of the non-corrected residue percent at the frequency of the swing depending on the value corresponding to a zoom magnification detected by the zoom detection means. 
   The correction quantity generating means is used, for example, that varies a characteristic of a non-corrected residue percent at a frequency of the swing so that, with a larger zoom magnification, a correction level gets stronger in a low frequency band of the swing. 
   A second unintentional hand movement canceling device according to the invention includes; zoom detection means detecting a value corresponding to a zoom magnification; swing detection means detecting a swing of an image; state discriminating means discriminating a swing state due to an intentional camera motion by a cameraman or a camerawoman from an unintentional hand movement state; a first correction quantity generating means generating a correction quantity to correct the swing of an image based on a swing quantity detected by the swing detection means and a value corresponding to a zoom magnification detected by the zoom detection means when it is determined by the state discriminating means that a current state is an unintentional hand movement, the correction quantity having a variable characteristic of a non-corrected residue percent at a frequency of the swing; and a second correction quantity generating means adopting a correction quantity of the immediately proceeding frame as a correction quantity for correcting the swing of the image when it is determined by the state discriminating means that a current state is a swing state due to an intentional camera motion by a cameraman or a camera woman, wherein the first correction quantity generating means varies a characteristic of the non-corrected residue percent at the frequency of the swing depending on a value corresponding to a zoom magnification detected by the zoom detection means. 
   The first correction quantity generating means, for example, varies a characteristic of non-corrected residue percent at the frequency of the swing so that with a larger zoom magnification, a correction level is stronger in a low frequency band of the swing. 
   The state discriminating means, for example, determines that a swing is in a swing state caused by an intentional camera movement of a cameraman or a camerawoman if one of the following conditions (a), (b) and (c) is satisfied: 
   (a) Frames having the same direction of the swing detected by the swing detecting means continuously occur and the number of the frames in continuation is a first threshold value or more; 
   (b) Frames having correction values of a upper limit value or more of a correction range generated by the first correction quantity generating means continuously occur and the number of the frames in continuation is a second threshold value or more; and 
   (c) Frames having the same direction of the swing detected by the swing detecting means continuously occur and an integral value of the swing in the frames that continuously occur in the same direction is a third. threshold value or more of an image angle. 
   The state discriminating means includes, for example, a threshold value control means controlling the first threshold value, the second threshold value and the third threshold value so as to be adapted for a value corresponding to a zoom magnification detected by the zoom detection means. 
   The threshold value control means controls, for example, the first threshold value, the second threshold value and the third threshold value so that with a smaller zoom magnification, the first threshold value, the second threshold value and the third threshold value are decreased. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram showing an electric configuration of a video camera. 
       FIG. 2  is a block diagram showing an electric configuration of a movement detecting circuit. 
       FIG. 3  is a model diagram showing plural motion vector detecting regions set in an image area. 
       FIG. 4  is a model diagram showing plural sampling points set in small regions in each motion vector detecting region of  FIG. 3  and one representative point. 
       FIG. 5  is a model diagram showing a relationship between a frame memory and a trimming frame. 
       FIG. 6  is a model diagram showing a relationship between a frame memory and a trimming frame when a video camera moves in a right direction. 
       FIG. 7  is a model diagram showing a relationship between an integral vector and a trimming frame. 
       FIG. 8  is a model diagram for describing a correction range for an unintentional hand movement. 
       FIG. 9  is model diagram for describing a processing in a case where a movement exceeds a correction range for an unintentional hand movement. 
       FIG. 10  is a graph showing a relationship between a swing frequency and a non-corrected residue percent with a damping coefficient as a parameter. 
       FIG. 11  is a flowchart showing operations in a video camera  10  performed for each frame. 
       FIG. 12  is a flowchart showing a procedure for a first state determination processing in step S 10  of  FIG. 11 . 
       FIG. 13  is a flowchart showing a procedure for a second state determination processing in step S 11  of  FIG. 11 . 
       FIGS. 14A ,  14 B and  14 C are graphs showing relationships between the number of frames and a movement quantity of a displayed image (figure) of a video camera  10  in a case where an unintentional hand movement state changes to a panning state as an actual state at an optical wide end. 
       FIGS. 15A and 15B  are graphs showing relationships between the number of frames and a movement quantity of a displayed image (figure) of a video camera  10  in a case where an unintentional hand movement state changes to a panning state as an actual state at an optical telephoto end. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Description will be given of examples of the invention below with reference to the accompanying drawings. 
     FIG. 1  shows a configuration of a video camera. 
   The video camera  10  includes: a solid state image pick-up element  12  such as CCD in which a light signal from an object (not shown) inputted from a lens  11  is converted to an electric signal. An electric signal from the solid state image pick-up element  12  is inputted to a camera circuit  13 . The camera circuit  13 , as well known, includes a sample holding circuit to sample-hold an electric signal from the solid state image pick-up element  12 . Not only is a level of a sample-held electric signal adjusted by AGC, but a synchronizing signal is also attached thereto by a synchronizing signal attaching circuit. In such a way, the camera circuit  13  converts an image signal from the solid state image pick-up element  12  to an analog video signal. 
   The analog video signal outputted from the camera circuit  13  is further converted to a digital video signal by an A/D converter  14 . A digital video signal outputted from the A/D converter  14  is given to a movement detecting circuit (swing detecting means)  18  and at the same time, written into a frame memory  15  by a memory control circuit  21 . 
     FIG. 2  shows a configuration of a movement detecting circuit  18 . 
   The movement detecting circuit  18  detects a motion vector using, for example, a well known representative point matching method. Description will be given of an outline of the representative point matching method. Plural motion vector detection regions E 1  to E 4  are, as shown in  FIG. 3 , set in an image area of each frame. The motion vector detection regions E 1  to E 4  are the same as one another in size. Each of the motion vector detection regions E 1  to E 4  is divided into plural small regions e. In this example, each of the motion vector detection regions E 1  to E 4  is divided into 30 small regions e. Each of the small regions e is constituted of, for example, 32 pixels×16 rows. Plural sampling points S and one representative point R are, as shown in  FIG. 4 , set in each of the small regions e. 
   A difference between a pixel value (luminance value) at sampling points S in each of the small regions e in a current frame and a pixel value (luminance value) of the representative point R of the corresponding small regions e in the preceding frame (correlation values at the respective sampling point) are obtained in each of the motion vector detection regions E 1  to E 4 . Then, correlation values are added and accumulated individually at the sampling points S with the respective same displacements from the representative point R of all the small regions e in each of the motion vector detection regions E 1  to E 4 . Therefore, the correlation accumulated values in number corresponding to the number of the sampling points S in one small region e are obtained in each of the motion vector detection regions E 1  to E 4 . 
   In each of the motion vector detection regions E 1  to E 4 , a displacement from the representative point R having the minimum correlation accumulated value, that is, the displacement of a point with the highest correlation is extracted as a motion vector of the motion vector detection regions E 1  to E 4 . 
   The movement detection circuit  18  includes an input end  31  at which a digital video signal from the A/D converter  14  is received and a digital video signal inputted from the input end  31  is given to a representative point memory  33  and a subtraction circuit  34  through a filter  32 . The filter  32  is a kind of a digital low pass filter and used in order to improve an S/N ratio and secure sufficient detection precision with fewer representative points. The representative point memory  33  memorizes positional data and luminance data of the representative point R in each of the small regions e of each of the motion vector detection regions E 1  to E 4  shown in  FIG. 3 . 
   The subtraction circuit  34  performs subtraction between luminance data of the representative point of the preceding frame given from the representative point memory  33  and luminance data of the sampling points S of a current frame given from the input end  31  in each of the small regions e of each of the motion vector detection regions E 1  to E 4  to calculate a result in absolute value (a correlation value at each sampling point). Obtained correlation values at the sampling points are given to an accumulation adding circuit  35 . 
   The accumulation adding circuit  35  adds and accumulates correlation values individually at the points having the same displacement from the representative point R in all the small regions e in each of the motion vector detection regions E 1  to E 4 . The correlation accumulated values are given to an arithmetic and logic circuit  36 . 
   The arithmetic and logic circuit  36  obtains not only the average value of correlation values in each of the motion vector detection regions E 1  to E 4 , but also positional data of the pixel with the minimum correlation accumulated value. In such a way, the average values of correlation accumulated values, the minimum correlation accumulated values and positional data of the pixel with the minimum correlation value obtained in each of the respective motion vector detection regions E 1  to E 4  are given to a microcomputer  20  (see  FIG. 1 ) from an output end  37 . 
   The microcomputer  20  calculates a motion vector of the entire image (hereinafter referred to simply as overall motion vector) based on data given from the arithmetic and logic circuit  36 . To begin with, a displacement from the representative point of a pixel with the minimum correlation accumulated value is obtained based on positional data of a pixel with the minimum correlation accumulated value in each of the motion vector detection regions E 1  to E 4  and the displacements are used as motion vectors (partial motion vectors) of the respective motion vector detection regions E 1  to E 4 . Note that in order to better detection precision of partial motion vectors, correlation accumulated values of 4 pixels surrounding the pixel with the minimum correlation accumulated value may also be used and interpolated to calculate positional data of the pixel with the minimum correlation accumulated value. 
   The microcomputer  20  determines whether or not a value obtained by dividing the average value of the correlation accumulated values with the minimum correlation accumulated value is more than a given threshold value and further determines whether or not the average value of correlation accumulated values is a predetermined value or more in each of the motion vector detection regions E 1  to E 4 ; thereby determines whether or not partial motion vectors obtained in each of the motion vector detection regions E 1  to E 4  is reliable, that is, whether each of the motion vector detection regions E 1  to E 4  is valid or invalid. If, in a motion vector detection region, a value obtained by dividing the average value of the correlation accumulated values with the minimum correlation accumulated value is more than a given threshold value and the average value of the correlation accumulated values is more than a predetermined value, the motion vector detection region is regarded as a valid region. 
   To be concrete, whether or not a motion vector detection region is valid or invalid is determined in a way described below. First of all, if a contrast of a screen image is low, a luminance difference is low; therefore, the correlation accumulated value is decreased. For example, if the entire screen image is white, the correlation accumulated value is reduced. In such a case, a reliability is lost; therefore a motion vector detection region is regarded as valid when a relation that the average value of the correlation accumulated value≧a predetermined value. Note that the predetermined value is empirically determined. 
   In a case where a moving object exists in a motion vector detection region, a correlation accumulated value in a portion occupied by the moving object is different from a correlation accumulated value in a portion not occupied by the moving object and the portion occupied by the moving object takes various correlation accumulated values, which are generally larger (a correlation is low). Therefore, in a case where a moving object is in a motion vector detection region, a possibility is low that the minimum correlation accumulated value is high and there is a risk that a motion vector (partial motion vector) in a motion vector detection region is erroneously detected. 
   If a partial motion vector is erroneously detected, an overall motion vector is erroneously detected. If the average value of the correlation accumulated values is large, the detection can be reliable even if the minimum correlation accumulated value is large to some extent. On the other hand, if the average value of the correlation accumulated values is small, the detection cannot be relied on unless the minimum correlation accumulated value is smaller. Hence, to be concrete, a motion vector detection region satisfying a condition of (the average value of correlation accumulated values)/(the minimum correlation accumulated value)&gt;5 is determined as a valid region and a partial motion vector of a motion vector detection region not satisfying the condition is not used to thereby prevent a harmful influence due to erroneous detection. 
   Whether or not each of the motion vector detection regions is valid is determined with the two conditions. Then, the average of partial motion vectors of motion vector detection regions each of which has been determined to be a valid region is obtained, the average is adopted as a movement quantity between frames, that is used as a movement quantity between frames, that is as the overall motion vector V n . Overall motion vector V n  expresses a movement quantity and a direction of the movement between the frames. The microcomputer  20  obtains an integral vector S n  using the overall motion vector V n . Description will be given later of a way to obtain the integral vector S n . The integral vector S n  expresses a distance from the center of a frame memory  15  to the center of a display region (a trimming frame). 
   In correction for an unintentional hand movement, the correction is performed by changing a position of a display region in the frame memory  15  (image trimming position). In  FIG. 5 , there is shown a relationship between the frame memory  15  and the trimming frame  100 . A region enclosed by the trimming frame  100  in the frame memory  15  is displayed as a picked-up image. An initial position of the trimming frame  100  is set at a position where the center of the trimming frame  100  coincides with the center of the frame memory  15 . The initial position is moved so as to be adapted for a detected motion vector. For example, in  FIG. 6 , there is shown a relationship between the frame memory  15  and the trimming frame  100  when the video camera moves to the right. When the video camera is moved to the right, the object moves in the frame memory to the left. On this occasion, the trimming frame  100  is moved in a direction opposite the movement of the video camera by the movement quantity of the video camera, thereby no change occurs in the displayed screen image (figure) and the unintentional hand movement is cancelled. 
     FIG. 7  shows a relationship between an integral vector S n  and a trimming frame  100 . A position of the trimming frame  100  is given with coordinates Ot of the center of the trimming frame  100  in an XY coordinate system with the center O of the frame memory  15  as the origin. If an integral vector of the current frame is indicated with S, a point in a distance indicated by the integral vector S in a direction shown by the integral vector S from the center O of the frame memory is the center Ot of the trimming frame  100 . 
   Here, as shown in  FIG. 8 , a correction range for an unintentional hand movement covers a range at which the trimming frame  100  reaches an end of the frame memory  15 . That is, ranges of a horizontal component Sh and a vertical component Sv of the integral vector S are Sh-min to Sh-max; and Sv-min to Sv-max in  FIG. 8 , respectively. 
   In a case where the video camera, as shown in  FIG. 9 , moves by a great distance and the horizontal component Sh of the integral vector S exceeds a limit value of the correction range, the horizontal component Sh is set to Sh-min (the limit value) if the horizontal component is smaller than Sh-min, while the horizontal component Sh is set to Sh-max (the limit value) if the horizontal component is larger than Sh-max. In a case where the vertical component Sv exceeds a limit value of the correction range, similarly to the above, the vertical component Sv is set to Sv-min (the limit value) if the vertical component is smaller than Sv-min, while the vertical component Sv is set to Sv-max (the limit value) if the vertical component is larger than Sv-max. 
   A calculation method for an integral vector S n  is different according to whether a current state is an unintentional hand movement state or a panning or tilting state. The states can be discriminated therebetween by the microcomputer  20 . Data which indicates whether a current state is an unintentional hand movement state or a panning or tilting state is stored in a memory (not shown) of the microcomputer  20 . 
   In the unintentional hand movement state, the microcomputer  20  obtains a damping coefficient K using a lens focal point distance F in terms of 35 mm film acquired from the focal point distance detecting circuit  19 , the minimum focal point distance F min  and the maximum focal point distance F max , set in advance and the minimum damping coefficient value K min  and the maximum damping coefficient value K max , set in advance according to the following equation (1). In this example, a damping coefficient K is set in the range of from 0.9 to 0.95 for a focal point distance in the range of from 38 to 280 mm. 
   
     
       
         
           
             
               
                 K 
                 = 
                 
                   
                     K 
                     min 
                   
                   + 
                   
                     
                       
                         F 
                         - 
                         
                           F 
                           min 
                         
                       
                       
                         
                           F 
                           max 
                         
                         - 
                         
                           F 
                           min 
                         
                       
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           K 
                           max 
                         
                         - 
                         
                           K 
                           min 
                         
                       
                       ) 
                     
                   
                 
               
             
             
               
                 ( 
                 1 
                 ) 
               
             
           
         
       
     
   
   An integral vector S n  of a current frame is calculated using the obtained damping coefficient K and the overall motion vector V n  and the integral vector S n−1  of the preceding frame according to the following equation (2).
 
 S   n   =K·S   n−1   +V   n   (2)
 
   By controlling a damping coefficient K, a characteristic of a frequency of unintentional hand movement to be cancelled can be altered.  FIG. 10  shows a relationship between a swing frequency [Hz] and a non-corrected residue percent with a damping coefficient K as a parameter. A non-corrected residue percent is defined as a proportion (%) of an amplitude in a swing after correction relative to an amplitude of a swing before the correction. For example, in a case where K=1.0, a detected movement can be perfectly corrected. In a case where K=0.90, a swing of 2 [Hz] is corrected by about 50% and a swing of 5 [Hz] is corrected by about 70%. That is, with a smaller damping coefficient K adopted, a correction level on a swing in a low frequency band is weakened. 
   By adopting the above calculation equation (1), in more of depth on the optical wide side with smaller zoom magnification (smaller focal point distance), a damping coefficient K is smaller. Therefore, since in more of depth on the optical wide side, a correction level for swing in the low frequency band is weakened, even in a case where detection in a panning or tilting state has failed, some of movement of a video camera when a panning or tilting state gets started remains not corrected to thereby alleviate a stick feeling. On the other hand, on the optical telephoto side with a larger zoom magnification (larger focal point distance), a damping K becomes larger and even a swing in a low frequency band is strongly corrected, while since a movement of an image when in panning and tilting is greatly larger than on the optical wide side and the correction range is exceeded in an instant, a stick feeling is naturally smaller. To the contrary, by strongly correcting a swing in the low frequency band as well, sufficient correction for unintentional hand movement can be effected. 
   In a panning or tilting state, the microcomputer  20 , as shown in the following equation (3), regards the integral vector S n−1  of the immediately preceding frame which is stored in the memory of the microcomputer  20  as the integral vector S n  of the current frame. That is, it means that no correction is conducted for unintentional hand movement.
 
 S   n   =S   n−1   (3)
 
   A transition from the unintentional hand movement to a panning or tilting state requires that one of the transition conditions (a), (b) and (c) is satisfied. 
   (a) A first condition for transition from an unintentional hand movement state to a panning or tilting state is that frames having overall motion vectors V n  in the same direction continuously occur and the number of the frames in continuation is a threshold value TH 1  or more. 
   To be concrete, frames having overall motion vectors V n , directions (upward or downward) of vertical components of which are the same continuously occur, and the number of the frames in continuation is a threshold value TH 1  or more or frames having overall motion vectors V n  directions (left or right) of horizontal components of overall motion vectors V n  of which are the same continuously occur and the number of the frames in continuation is a threshold value TH 1  or more. 
   (b) A second condition for transition from an unintentional hand movement state to a panning or tilting state is that frames having integral vectors S n  is a limit value or more of a correction range continuously occur and the number of the frames in continuation is a threshold value TH 2  or more. 
   To be concrete, frames having integral vectors S n , vertical components of which is a limit value or more of a correction range continuously occur and the number of the frames in continuation is a threshold value TH 2  or more, or frames having integral vectors S n , horizontal components of which is a limit value or more of a correction range continuously occur and the number of the frames in continuation is a threshold value TH 2 . 
   Note that in a case where a vertical component Sv of an integral vector S n  falls outside a limit value of a correction range, a vertical component Sv is set to Sv-min (limit value) if being smaller than Sv-min, while a vertical component Sv is set to Sv-max(limit value) if being larger than Sv-max. In a case where a horizontal component Sh of an integral vector S n  falls outside a limit value of a correction range, a horizontal component Sh is set to Sh-min (limit value) if being smaller than Sh-min, while a horizontal component Sh is set to Sh-max (limit value) if being larger than Sh-max. 
   (c) A third condition for transition from an unintentional hand movement state to a panning or tilting state is that frames having overall motion vectors V n  in the same direction continuously occur and an integral value of the overall motion vectors V n  in continuation in the same direction is a proportion of a threshold value TH 3  or more of an image angle (an image size of a trimming frame). 
   To be concrete, frames having overall motion vectors V n  directions of vertical components (upward or downward) of which are the same continuously occur and an integral value of the vertical components of the overall motion vectors V n  is a proportion of a threshold value TH 3  or more of a width in a direction, upward or downward, of a trimming frame; or frames having overall motion vectors V n  directions (left or right) of horizontal components of which are the same continuously occur and an integral value of the horizontal components of the overall motion vectors V n  which continuously occur in the same direction is a proportion of TH 3  or more of a width in a direction, left or right, of a trimming frame. 
   The determination threshold values TH 1 , TH 2  and TH 3  of the (a), (b) and (c) are varied according to a focal point distance. To be concrete, a threshold value is calculated using the following equation (4): 
   
     
       
         
           
             
               
                 TH 
                 = 
                 
                   
                     TH 
                     min 
                   
                   + 
                   
                     
                       
                         F 
                         - 
                         
                           F 
                           min 
                         
                       
                       
                         
                           F 
                           max 
                         
                         - 
                         
                           F 
                           min 
                         
                       
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           TH 
                           max 
                         
                         - 
                         
                           TH 
                           min 
                         
                       
                       ) 
                     
                   
                 
               
             
             
               
                 ( 
                 4 
                 ) 
               
             
           
         
       
     
   
   In the equation (4), F is a current focal point distance, F min  and F max  are the minimum focal point distance and the maximum focal point distance, which are determined in advance, TH min  and TH max  are the minimum threshold value and the maximum threshold value, which are set in advance. In this example, the following values are adopted as F min  and F max , and TH min  and TH max  for each of the determination conditions. 
   F min= 38 mm, F max= 280 mm 
   (a) In calculation of TH 1 , TH min= 20 frames, TH max= 30 frames 
   (b) In calculation of TH 2 , TH min= 5 frames, TH max= 10 frames 
   (c) In calculation of TH 3 , TH min= 15%, TH max= 20% 
   For example, as to TH 1 , it is determined at an optical telephoto end that panning or tilting gets started if the number of frames in continuation is 30, while it is determined in an optical wide end that panning or tilting gets started, if the number of frames in continuation is 20. In such a way, since a determination threshold value is variable according to a focal point distance so that determination of panning or tilting on the wide side is loose, a detection sensitivity of panning or tilting on the wide side having a more conspicuous stick feeling is raised to thereby decrease the stick feeling. 
   A transition from a panning or tilting state to an unintentional hand movement state requires that one of the transition conditions (a), (b) and (c) is satisfied. 
   (a) A first transition condition from a panning or tilting state to an unintentional hand movement is that frames having overall motion vectors V n  of 0.5 pixel or less continuously occur and the number of the frames in continuation is 10 or more. 
   To be concrete, frames having overall vectors V n , vertical components of which is 0.5 pixel or less continuously occur and the number of the frames in continuation is 10 or more, or frames having overall vectors V n horizontal components of which is 0.5 pixel or less and the number of the frames in continuation is 10 or more. 
   (b) A second transition condition from a panning or tilting state to an unintentional hand movement is that frames having overall motion vectors V n  in a direction opposite a direction of overall motion vectors V n  when an unintentional hand movement state changes to a panning or tilting state continuously occur and the number of the frames is 10 or more. 
   To be more concrete, frames having overall motion vectors V n  directions of vertical components of which are opposite directions of vertical components of overall motion vectors V n  when an unintentional hand motion state changes to a panning or tilting state continuously occur and the number of the frames in continuation is 10 or more or frames having overall motion vectors V n  directions of horizontal components of which are opposite directions of horizontal components of overall motion vectors V n  when an unintentional hand motion state changes to a panning or tilting state continuously occur and the number of the frames in continuation is 10 or more. 
   An integral vector S n  thus obtained is given to the memory control circuit  21 . The memory control circuit  21  determines a start address for reading the frame memory  15  based on a given integral vector S n  and reads a digital video signal stored in the frame memory  15  at the address. That is, the memory control circuit  21  moves a trimming frame  100  in the frame memory  15  based on the integral vector S n  calculated by the microcomputer  20 . 
   A digital video signal read from the frame memory  15  by the memory control circuit  21  is sent to the electronic zoom circuit  16 . The electronic zoom circuit  16 , in order to obtain a video signal corresponding to a size of the memory frame  15 , enlarges an image using an interpolation method based on the digital video signal read from the frame memory  15 . A digital video signal outputted from the electronic zoom circuit  16  is sent to the output terminal  17 . 
     FIG. 11  shows operations in the video camera  10  performed for each frame. 
   Flag used as a flag memorizing whether a current state is an unintentional hand movement state or a panning or tilting state. If Flag is reset (Flag=0), it shows that the current state is an unintentional hand movement state, while if Flag is set (Flag=1), it shows that the current state is a panning or tilting state. 
   To begin with, Flag is reset (Flag=0) (step S 1 ). That is, an unintentional hand movement state is set as an initial state. 
   Partial motion vectors are obtained based on positional data of the pixel with the minimum correlation accumulated value in each of the motion vector detection regions E 1  to E 4  (step S 2 ). 
   Then, it is determined whether each of the motion vector detection regions E 1  to E 4  is a valid region or an invalid region based on the average correlation accumulated value and the minimum correlation accumulated value in each of the motion vector detection regions E 1  to E 4  (step S 3 ). Thereby, it is determined whether or not a valid region exists (step S 4 ). 
   If a valid region exists, the average of partial motion vectors of the valid region is adopted as an overall motion vector V n  (step S 5 ). Then, the process advances to step S 7 . If no valid region exists, an overall motion vector V n  is set to 0 (step S 6 ). Then, the process advances to step S 7 . In step S 7 , it is determined whether or not Flag=0. That is, it is determined whether or not a current state is an unintentional hand movement or a panning or tilting state. 
   In a case where Flag=0, that is, if a current state is an unintentional hand movement, a focal point distance in terms of 35 mm film is acquired from the focal point distance detection circuit  19  and a damping coefficient K is calculated based on the equation (1) (step S 8 ). An integral vector S n  is calculated based on the equation (2) using the calculated K (step S 9 ). Then, after the first state determination processing is conducted (step S 10 ), the process advances to step S 13 . The first state determination processing will be described later. 
   In step S 7 , if Flag=1, that is, if a current state is a panning or tilting state, an integral vector S n  is calculated based on the equation (3) (step S 11 ). Then, after the second state determination processing is conducted (step S 12 ), the process advances to step S 13 . The second state determination processing will be described later. 
   In step S 13 , a position of a trimming frame is calculated based on the integral vector S n  calculated in step S 9  or S 11 . Then, the current process is terminated. 
     FIG. 12  shows a procedure for the first state discrimination processing in step S 10  of  FIG. 11 . 
   First of all, a current lens focal point distance F in terms of a 35 mm film is acquired (step S 21 ). Threshold values for determination of a panning or tilting state Th 1 , Th 2  and Th 3  are calculated based on the equation (4) using the acquired focal point distance F (step 22). 
   In this example, Th 1 , Th 2  and Th 3  are calculated based on the following equations (5), (6) and (7).
 
 Th 1=20+10*( F− 38)/(280−38)  (5)
 
 Th 2=5+5*( F −38)/(280−38)  (6)
 
 Th 3=15+5*( F −38)/(280−38)  (7)
 
   Then, it is determined whether or not the first transition condition from an unintentional hand movement state to a panning or tilting state is satisfied (step S 23 ). That is, it is determined whether or not a condition that frames having overall motion vectors V n  in the same direction continuously occur and the number of the frames in continuation is the threshold value TH 1  or more is satisfied. If the first transition condition is satisfied, it is determined that a current state is a panning or tilting state, that is, it is determined that an unintentional hand movement state has been transitioned to a panning or tilting state and Flag is set (Flag=1) (step S 27 ). Then, the process moves to step S 13  of  FIG. 11 . 
   If the first transition condition is not satisfied, it is determined whether or not the second transition condition from an unintentional hand movement state to a panning or tilting state is satisfied (step S 24 ). That is, it is determined whether or not a condition that frames having integral vectors S n  that are a limit value or more of a correction range continuously occur and the number of the frames in continuation is the threshold value TH 2  or more is satisfied. If the second transition condition is satisfied, it is determined that a current state is a panning or tilting state, that is, it is determined that an unintentional hand movement state has been transitioned to a panning or tilting state and Flag is set (Flag=1)(step S 27 ). Then, the process moves to step S 13  of  FIG. 11 . 
   If the second transition condition is not satisfied, it is determined whether or not the third transition condition from an unintentional hand movement state to a panning or tilting state is satisfied (step S 25 ). That is, it is determined whether or not a condition that frames having overall motion vectors V n  in the same direction continuously occur and an integral value of the overall motion vectors V n  continuously occur in the same direction is a predetermined portion TH 3  (%) or more of an image angle (an image size of a trimming frames) is satisfied. If the third transition condition is satisfied, it is determined that a current state is a panning or tilting state, that is, it is determined that an unintentional hand movement state has been transitioned to a panning or tilting state, and Flag is set (Flag=1) (step S 27 ). Then the process moves to step S 13  of  FIG. 11 . 
   If the third transition condition is not satisfied, it is determined that a current state is an. unintentional hand movement state and Flag is reset (Flag=0) (step S 26 ). Then, the process moves to step S 13  of  FIG. 11 . 
     FIG. 13  shows a procedure for the second state determination processing in step S 11  of  FIG. 11 . 
   To begin with, it is determined whether or not the first transition condition from a panning or tilting state to an unintentional hand movement state is satisfied (step S 31 ). That is, it is determined whether or not a condition that frames having overall motion vectors V n  of 0.5 pixel or less continuously occur and the number of the frames in continuation is 10 or more is satisfied. If the first condition is satisfied, it is determined that a current state is an unintentional hand movement state, that is, it is determined that a panning or tilting state has been transitioned to an unintentional hand movement and Flag is reset (Flag=0) (step S 34 ). Then, the process moves to step S 13  of  FIG. 11 . 
   If the first transition condition is not satisfied, it is determined whether or not the second transition condition from a panning or tilting state to an unintentional hand movement state is satisfied (step S 32 ). That is, it is determined that a condition that frames having overall motion vectors V n  in directions opposite directions of overall motion vectors V n  when an unintentional hand movement state is transitioned to a panning or tilting state continuously occur and the number of the frames in continuation is 10 or more is satisfied. If the second transition condition is satisfied, it is determined that a current state is an unintentional hand movement state, that is, it is determined that a panning or tilting state has been transitioned to an unintentional hand movement state and Flag is reset (Flag=0) (step S 34 ). Then the process moves to step S 13  of  FIG. 11 . 
   If the second transition condition is not satisfied, it is determined that a current state is a panning or tilting state and Flag is set (Flag=1) (step S 33 ). Then the process moves to step S 13  of  FIG. 11 . 
   In the video camera  10  operated in such a way, a damping coefficient K is decreased on an optical wide side where a stick feeling was conventionally conspicuous when a current state is a panning or tilting state. Hence, on the optical side, since a correction level for a swing in a low frequency band is weakened, some of movement of a video camera at an initial stage after the start of a panning or tilting operation remains non-corrected even in a case where detection of a panning or tilting state fails and a stick feeling is alleviated. 
   Since the determination threshold values TH 1 , TH 2  and TH 3  are altered so as to be adapted for a focal point distance F so that it is determined with ease that in more of depth on the optical wide side, a current state is a panning or tilting state, a detection sensitivity of a panning or tilting state in the optical wide side becomes higher and the sick feeling is alleviated on the optical wide side. 
   Therefore, as compared with a conventional case, operability on the optical wide side is improved (a clattering motion is reduced) and correction for an unintentional hand movement with a good operability can be realized over the all zoom regions. 
     FIGS. 14A ,  14 B and  14 C show relationships between the number of frames and a movement quantity of a displayed image (figure) of the video camera  10  in a case where an unintentional hand movement state changes to a panning state as an actual state at an optical wide end. 
     FIG. 14A  shows a movement quantity of the figure in a case where no unintentional hand movement is cancelled,  FIG. 14B  shows a movement quantity of a figure in a case where correction for an unintentional hand movement is applied with a conventional technique (where a damping coefficient K is fixed to 0.95) and  FIG. 14C  shows a movement quantity of a figure in a case where correction for an unintentional hand movement correction is applied in the example (where a damping coefficient K is set to 0.9). 
   In a case where an actual state is an unintentional hand movement as shown in a period T 1 , it is determined in the video camera  10  as well that the actual state is an unintentional hand movement, and correction for the unintentional hand movement is applied with K=0.95 in a conventional technique ( FIG. 14B ) and with K=0.9 in the example ( FIG. 14C ). In the example ( FIG. 14C ), since a damping coefficient K is small, a non-corrected residue percent is comparatively high. 
   In a case where an unintentional hand movement state changes to a panning state as an actual state as shown in a period T 2 , it is determined even at an initial stage after the change that an actual state is an unintentional hand movement state; therefore, correction for an unintentional hand movement is applied, thereafter one of the first condition, the second condition and the third condition from an unintentional state to a panning or tilting state is satisfied and a result of determination by the video camera  10  is transitioned from an unintentional hand movement to panning or tilting state. As a result, no correction of an unintentional hand movement is applied and a movement of a figure after the correction becomes equal to a case where no correction for an unintentional hand movement is applied. 
   In a period till a result of determination of the video camera  10  is transitioned from an unintentional hand movement to a panning or tilting state after an unintentional state changes to a panning state as an actual state, a damping coefficient K is large in a conventional technique ( FIG. 14B ) and a swing of a low frequency component is strongly corrected; therefore, almost no gentle rise when a panning operation gets started is observed and not only does a stick phenomenon become conspicuous, but a phenomenon also becomes conspicuous that a screen image abruptly moves immediately after the transition to a panning or tilting state. On the other hand, in the example ( FIG. 14C ), since a damping coefficient K is small and a correction level for a swing of a low frequency component is weak, a gentle rise at the start of a panning operation remains more or less, thereby alleviating the stick phenomenon. 
     FIGS. 15A to 15B  show relationships between the number of frames and a movement quantity of a displayed image (a figure) of the video camera  10  in a case where an unintentional hand movement state changes to a panning state as an actual state at an optical telephoto end. 
     FIG. 15A  shows a movement quantity of a figure in a case where no correction for unintentional hand movement is applied and  FIG. 15B  shows a movement quantity of a figure in a case where correction for an unintentional hand movement was applied with a conventional technique and in the example (a damping coefficient K=0.95). 
   In a case where an actual state is, as shown in the period T 1 , an unintentional hand movement, it is determined in a conventional technique and the example that the actual state is an unintentional hand movement state and correction for an unintentional hand movement is applied with K=0.95. In a case where an unintentional hand movement, as shown in the period T 2 , changes to a panning state as an actual state, it is determined that a state even at an initial stage after the change is an unintentional hand movement state; therefore, correction for an unintentional hand movement is applied, and thereafter, one of the first transition condition, the second transition condition and the third transition condition from an unintentional hand movement to a panning or tilting state is satisfied, a result of the determination by the video camera  10  transitions from an unintentional hand movement state to a panning or tilting state. As a result, no correction for an unintentional hand movement is applied and a movement of a figure after the correction becomes equal to a case where no correction for an unintentional hand movement is applied. 
   Immediately after an unintentional hand movement state changes to a panning state as an actual state, it is determined that a current state is an unintentional hand movement state, while a movement in a display image is by far larger on the optical telephoto end than on the optical wide end and the movement falls outside a correction range in an instant, which renders an effect of an unintentional hand movement cancellation extinct; therefore, the stick feeling is naturally less at the optical telephoto end. 
   In the example, since the stick feeling is originally less on the optical telephoto side, even a swing with a low frequency can be sufficiently corrected with respect of an unintentional hand movement with a large damping coefficient in a similar way to a conventional technique, while on the optical wide side, a damping coefficient is reduced to retain a gentle rise as is at the start of an initial stage of a panning or tilting operation, thereby enabling the stick feeling to be reduced. 
   Note that a motion vector may be obtained, for example, using an angular velocity sensor, instead of a representative point matching method. Correction for an unintentional hand movement may also be applied, for example, by controlling a lens angle, a lens position or a light receiving element position instead of controlling a trimming position of an image memory.