Abstract:
A conventional movable range restricting function designates a movable range by using a numerical value of an angle of view. It is, therefore, difficult for a user to intuitively know this value. A trial and error basis is therefore necessary to obtain an optimum setting. Similarly, a user is required to set a value of the movable range of zoom without knowing beforehand the size of a zoomed object. In order to solve these problems, an image processing apparatus comprises a display control unit for displaying a panorama image on a display unit, the panorama image being formed by coupling a plurality of images taken with a controllable image pickup unit, and a setting unit for setting a visible range in the panorama image, an image in the visible range capable of being taken with the image pickup unit by controlling the unit, wherein the display control unit displays an image in the visible range set by the setting unit and an image outside of the visible range in different states capable of being visually discriminated.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a server for distributing images taken with an image pickup apparatus over a network. The invention also relates to an image distribution system having such a server and clients for viewing images distributed over the network, and more particularly to a system capable of controlling pan/tilt/zoom of a camera in response to a request from a client. 
     2. Description of the Related Art 
     There are many types of commercially available cameras (such as VC-C1 and VC-C3 of CANON K.K.) capable of controlling pan/tilt/zoom by connecting them to computers. Such cameras are simply called cameras hereinafter. A program WebView (CANON K.K.) is known which can distribute images to users on a network with such cameras. A server connected to a camera on the network is called a camera server. 
     By controlling pan/tilt/zoom, a camera connected to the server can take an image even in an undesired area. If a person taken with the camera is zoomed in too much, the person is likely to feel resistant against being taken. 
     A remote monitoring system is also known in which pan/tilt/zoom of a camera connected to a network is remotely controlled and images taken with the camera are transmitted via the network to browse them. This system is disclosed in Japanese Patent Application Laid-Open No. 10-042279 “Camera Controlling Apparatus and Method” by Sato and Yamakawa. According to Japanese Patent Application Laid-Open No. 10-042279, a visible range restricting function is provided by which the movable range of pan/tilt/zoom can be set by an angle of view by using a slider bar. For example, an image at 30 degrees or larger in the right direction is not allowed to take, or an image at 12 degrees, or smaller in the down direction is not allowed to take. If a client user can freely control pan/tilt/zoom and the like, an image which a camera setter does not desire to be looked at can be viewed by the client user. The visible range restricting function can avoid this. 
     However, a conventional movable range restricting function designates the movable range by using a numerical value of an angle of view. It is, therefore, difficult for a user to intuitively know this value. A trial and error basis is therefore necessary to obtain an optimum setting. Similarly, a user is required to set a value of the movable range of zoom without knowing beforehand the size of a zoomed object. 
     Another approach to controlling a camera is also known. With this approach, when controlling the camera, a client user designates a desired area in a panorama image of the whole photographing area of the camera taken beforehand. However, if a panorama image of a limited area is used, each time this limited area is changed, a camera setter is required to take again a new panorama image. 
     Since the panorama image of the whole photographing area is used not only by a client user but also by the administrator when the user visible range is limited, it is necessary to register the panorama image of the whole photographing area at the server. 
     The panorama image used is a still image and is not renewed by an image currently taken with the camera. It is not so much desirous, however, that a client user can look at even a still image outside of the visual range. It is preferable to provide some countermeasure so as not to be looked at the undesired image. For example, in the panorama image displayed in order to show the whole photographing area, an image outside of the visible range may be drawn in color or in mosaic. However, in this case, a client user controls the camera, being definitely conscious of the visible range restriction. The client user can know the details of the visible range restriction setting in the whole photographing area. The camera setter sensitive to security does not desire that such details are made public. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to solve all or at least one of the above-described problems. 
     It is another object of the invention to make a visible range restriction be intuitively set quickly while viewing an image. 
     It is still another object of the invention to make a zoom range be intuitively set quickly while viewing an image. 
     In order to achieve the above objects, an embodiment of the invention provides, an image processing apparatus comprising: a display control unit for displaying a panorama image on a display unit, the panorama image being formed by coupling a plurality of images taken with a controllable image pickup unit; and a setting unit for setting a visible range in the panorama image, permittable to be taken with the image pickup unit by controlling the unit, wherein the display control unit displays an image in the visible range set by the setting unit and an image out side of the visible range in different states capable of being visually discriminated. 
     An embodiment of the invention also provides an image processing apparatus comprising: a display control unit for displaying an image in a photographing area of a controllable image pickup unit on a display unit; a rectangle display unit for displaying a rectangle in the image displayed on the display unit, the rectangle indicating a zoom ability of the image pickup unit; a zoom ability setting unit for setting a range of the zoom ability of the image pickup unit; and a display change unit for changing a size of the rectangle in accordance with the setting made by the zoom ability setting unit. 
     It is another object of the present invention to provide an image processing apparatus and method and an image distribution system capable of making a client user not consicious of a movable range restriction. 
     In order to achieve the above object, an embodiment of the invention provides an image processing apparatus comprising: a receiving unit for receiving image information in a visible range in a whole photographing area of an image pickup unit; a display control unit for displaying an image in the visible range on a display unit in accordance with the image information received by the receiving unit, without displaying an area outside of the visible range; and a receiving unit for receiving an instruction to the visible range displayed on the display unit when the photographing area of the image pickup unit is changed. 
     An embodiment of the invention also provides an image processing apparatus comprising: a unit for generating a panorama image indicating a whole photographing area of a remotely controllable image pickup unit; a setting unit for setting a visual range by designating an area in the panorama image; a transmitting unit for transmitting an image in the visual range set by the setting unit; and a receiving unit for receiving a control of the image pickup unit, the control being performed by using the image in the visual range. 
     Other objects and features of the present invention will become apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing the structure of a camera server according to an embodiment of the invention. 
     FIG. 2 is a diagram illustrating a user interface. 
     FIG. 3 is a flow chart illustrating a visible range restriction setting operation according to an embodiment of the invention. 
     FIG. 4 is a block diagram showing the structure of an image distribution system according to an embodiment of the invention. 
     FIG. 5 is a block diagram showing the structure of software modules of the image distribution system of the embodiment. 
     FIG. 6 is a flow chart illustrating an operation of capturing a panorama image in a visible range. 
     FIGS. 7A and 7B are flow charts illustrating an operation of displaying a panorama image. 
     FIG. 8 shows examples of a moving image display window and a panorama image window. 
     FIGS. 9A,  9 B and  9 C illustrate a method of displaying a panorama image. 
     FIGS. 10A,  10 B and  10 C illustrate another method of displaying a panorama image. 
     FIG. 11 shows an example of an image in a narrow visible range. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     [First Embodiment] 
     FIG. 1 is a block diagram showing characteristic points of the invention. Elements in this block diagram will be described. 
     Reference numeral  101  represents a camera server using a personal computer. 
     Reference numeral  102  represents a display. 
     Reference numeral  103  represents a mouse land a keyboard. 
     Reference numeral  104  represents an input/output interface for connection between the server  101  and peripheral apparatus. 
     Reference numeral  105  represents a CPU for controlling various elements of the server  101 . 
     Reference numeral  106  represents a ROM storing a camera control program, a display control program and the like. 
     Reference numeral  107  represents a network I/O for inputting an image transmission request from a network and outputting an image taken with a camera  117  to the network and for performing other operations. 
     Reference numeral  108  represents a RAM for storing various executable programs which are read and executed under the control of CPU  105 . 
     Reference numeral  109  represents a control unit or executable program for controlling and operating various units essential to the invention. 
     Reference numeral  110  represents a panorama image display unit. A panorama image is formed beforehand and stored in an external storage unit. When a camera server execution program  116  is initiated, the panorama image is supplied to the panorama image display unit  110 . 
     Reference numeral  111  represents an area designation unit for setting a rectangular area whose size and position can be changed by dragging the corner of the area (rubber band) with a mouse. 
     Reference numeral  112  represents a clipping unit for clipping a rectangle designated by the area designation unit  111  from a panorama image. 
     Reference numeral  113  represents an image synthesis unit for synthesizing a plurality of images to form a single image. The image synthesis unit  113  also has a function of controlling the camera to take a plurality of images in response to a user instruction and synthesizing a panorama image in the whole photographing area of the camera. 
     Reference numeral  114  represents a monochrome image generating unit for generating a monochrome image from a color image. 
     Reference numeral  115  represents a setting value storing unit for storing a movable range value of pan/tilt/zoom. 
     Reference numeral  116  represents a camera server execution program. This program realizes a function similar to that of “Camera Controlling Apparatus and Method” described in Japanese Patent Application Laid-Open No. 10-042279. The contents of this program are detailed in Japanese Patent Application Laid-Open No. 10-042279 so that the description thereof is omitted. 
     The camera server  101  can limit the movable range of pan/tilt/zoom. This limit information is read from the setting value storing unit  115  and is used when a camera server execution program is executed. 
     Reference numeral  117  represents the camera whose pan/tilt/zoom can be controlled by the camera server  101 . 
     The units  109  to  115  and program  116  include executable programs and data which are stored in RAM  108  and executed by CPU  105 . 
     FIG. 2 shows an example of a user interface to be used particularly when the camera server controls pan/tilt/zoom and the like of the camera. 
     Reference numeral  201  represents a rubber band used for setting a visible range. A user on the network can set a visible range in which the camera can take an image, by changing the size of the rubber band by operating a mouse or the like on the display screen. 
     Reference numeral  202  represents zoom setting slider bars. The upper slider bar is used for setting a zoom limit, and the lower slider bar is used for setting a wide angle limit. By operating these bars, a user on the network can set the zoom range in which the camera can take an image. 
     Reference numeral  203  represents a pan/tilt value setting field used for setting the visible range by directly entering values of the visible range. The size and position of the rubber band  201  change with entered numerical values, whereas the numerical values change with the size and position of the rubber band  201  changed by the mouse or the like. 
     Reference numeral  204  represents a wide angle limit indicator indicating a wide angle limit of the camera. 
     Reference numeral  205  represents a zoom limit indicator indicating a zoom limit of the camera. 
     With reference to FIG. 2, the operation of the user interface will be described. 
     The size and position of the visible range setting rubber band  201  can be changed by using the mouse or the like. The inner area of this rectangle area is the visible range in which a color image is displayed. The outer area of the rectangle area is an invisible range in which a black and white image is displayed. The maximum size of the rubber band is equal to the panorama image area, and the minimum size is equal to the size of the zoom limit indicator indicating the zoom limit of the camera. 
     If the rubber band  201  is made too small, the movable range may become smaller than the zoom limit setting value. For example, if the wide angle limit is 50 degrees and the rubber band is made small at the right limit of 10 degrees and left limit of 10 degrees, i.e., a lateral pan width of 20 degrees, then the visible range becomes smaller than the wide angle limit. In such a case, the setting by the rubber band has a priority over the setting by the zoom range. In this case, the wide angle limit is automatically set to 20 degrees and the size of the wide angle indicator  204  and the value of the zoom setting slider bar are changed. 
     As the zoom setting slider bars  202  are moved, the indicators  204  and  205  are changed correspondingly. Centers of rectangles of the indicators are always coincident with the center of the panorama image, and only the sizes thereof change. The zoom limit value is never larger than the wide angle value. As the sizes of the indicators  204  and  205  are changed with the mouse or the like, the zoom setting slider bars  202  move correspondingly. 
     If the visible range setting rubber band is moved toward the side of the panorama image and the size thereof is reduced, the indicators and rubber band may cross or separate from each other. This proposes no problem because the indicators are used only for indicating the zoom setting values. 
     Next, with reference to FIG. 3, the operation of setting the visible range will be described. 
     The program starts at Step S 301 . 
     At Step S 302 , the control unit  109  initiates the camera server execution program  116  to read a panorama image indicating the whole photographing area of the camera and information on the panorama image (such as limit values of pan/tilt/zoom when there is no visible range limit). 
     At Step S 303 , the control unit  109  initiates the monochrome image generating unit  114  to generate a monochrome image of the panorama image. 
     At Step S 304 , the control unit  109  reads a currently set movable range of pan/tilt from the setting value storing unit  115  and initializes the area designation unit  111 . The control unit  109  initiates the image clipping unit  112  to clip an image in the visible range from the color panorama image. 
     At Step S 305 , the control unit  109  initiates the image synthesis unit  113  to synthesize the monochrome image generated at Step S 303  and the color image acquired at Step S 304 . A synthesized image is therefore formed having the monochrome image outside of the visible range and the color image inside of the visible range. 
     At Step S 306 , the control unit  109  initiates the panorama image display unit  110  to draw the image synthesized at Step S 305 . The zoom movable range is acquired from the setting value storing unit  115  to draw the zoom indicators  204  and  205  on the panorama image. 
     At Step S 307 , the operation waits for a user input. If there is a user input, the flow advances to Step S 308 . 
     At Step S 308  it is judged whether the user input is to operate the rubber band  201 . If the rubber band, the flow advances to Step S 309 , whereas if not, the flow advances to Step S 310 . 
     At Step S 309  it is judged whether the rubber band  201  changes its size smaller than the wide angle and zoom limit values. If the zoom limit values (wide angle and zoom limit values) are larger than the visible range, it is necessary to change the zoom limit values so that the flow advances to Step S 311 , whereas if not, the flow advances to Step S 312 . 
     At Step S 312 , the limit values of pan/tilt/zoom are stored in the setting value storing unit  115  to thereafter return to Step S 304 . 
     At Step S 310  it is judged whether the user input is the operation of the slider bars  202 . If so, the flow advances to Step S 311 , whereas if not, the flow advances to Step S 313 . 
     At Step S 311 , the limit values of wide angle and zoom are renewed. First, the values set by the user are acquired from the slider bars  202 . If the set values are out of the visible range, these values are changed so that they are set in the visible range. The values are also changed so that the zoom limit is not larger than the wide angle limit. The slider bars  202  are then moved to take new values to thereafter advance to Step S 312 . 
     At Step S 313  it is judged whether the visible range restriction setting has been completed. If completed, the flow advances to Step S 314 , whereas if not, the flow returns to Step S 307 . 
     At Step S 314 , the camera server execution program  116  is initiated again. The camera server execution program  116  checks the data in the setting value storing unit  115  to limit the visible range. 
     At Step S 315  the visible range setting operation is terminated. 
     In this embodiment, an image in the visible range is displayed in color and an image outside of the visible range is displayed in black and white. Instead of the black and white, the image outside of the visible range may be displayed not at all or it may be displayed as a frame line. However, it is easier to set the visible range by looking at the area outside of the visible range, and if the image outside of the visible range is displayed not at all, it is hot easy to change the visible range, particularly to broaden the visible range. Further, if the frame line only is displayed, the inside and outside of the frame line are difficult to be discriminated at a glance. 
     In contrast, in this embodiment, although an image outside of the visible range is displayed, the color image in the visible range can be recognized more easily. Accordingly, the inside and outside of the visible range can be easily discriminated. Further, an image made public to users on the network can be recognized easily. 
     The invention is not limited only to this embodiment. 
     For example, an image in the visible range may be displayed in black and white and an image outside of the visible range is displayed in color. An image in the visible range may be displayed in black and white and an image outside of the visible range is displayed in inverted black and white. This is particularly effective for a monochrome display monitor. It is obvious that different color hues or different brightness may be used for the inside and outside of the visible range. In summary, it is sufficient if the images in the inside and outside of the visible range are displayed in a manner capable of being visually discriminated. 
     The images in the whole photographing area of the camera are synthesized to form the panorama image, and the visible range is set in this panorama image. The visible range can therefore be easily recognized. Although the panorama image is stored beforehand in the memory, the panorama image may be synthesized by initiating the image synthesis unit when the visible range is set. By using this newly generated panorama image, the visible range may be set. 
     Since the numerical values representative of the movable range are displayed at the same time when the visible range is displayed, the operation and degree of freedom of the visible range setting can be improved. User preference may be made effective when setting the visible range. For example, the visible range may be set first roughly by changing the rectangle area on the display screen, and then it is set finely by changing the numerical values, e.g., by changing 0.01°, when it is difficult to set the range by looking at the rectangle area. 
     Since the zoom ability is restricted by limiting the zoom movable range, it is possible not to, display a detailed image for the protection of privacy and business secret. If the setting is possible only by using numerical values, it is difficult to recognize to what degree an image can be magnified or the area of the image can be broadened. In this embodiment, however, the zoom ability can be easily set because it is possible to check the size of an image displayed on the display screen. Furthermore, since the indicators  204  and  205  and zoom setting slider bars  202  are displayed synchronously with a setting change, it is easy to recognize from the image the setting change by either of the indicators or bars. 
     The invention may be applied to a system constituted of a plurality of apparatus (e.g., host computer, interface, reader, Web server, camera server, and printer) or to each apparatus (e.g., Web server or camera server). 
     As described so far, according to the embodiment, images in the inside and outside of the visible range are displayed in a manner capable of being visually discriminated. It is therefore possible to intuitively and quickly set a visible range restriction. 
     Since the visible range is displayed on the panorama image, the visible range can be set easily. 
     An image in the visible range is displayed in color and an image outside of the visible range is displayed in black and white. Accordingly, an image in the visible range can be easily recognized visually and also an image outside of the visual range can be seen. It is therefore effective for changing the visual range. 
     Since the numerical values representative of the movable range are displayed at the same time when the visible range is displayed, the operation and degree of freedom of the visible range setting can be improved. 
     The zoom movable range to be set by limiting the zoom ability can be set intuitively and quickly by checking the size of an image displayed on the display screen. 
     The zoom ability can be changed easily by changing the size of the rectangular area because the size of an image can be checked. 
     [Second Embodiment] 
     FIG. 4 is a block diagram showing the structure of an image transfer system in which an image transmission server is connected via a network to image reception clients. 
     FIG. 5 is a diagram showing the structure of software modules to be executed by CPUs of the server and clients. 
     An image transmission server is connected via an image cable and a serial cable to a camera  1101  whose pan/tilt/zoom and the like can be controlled. An image taken with the camera is supplied via the image cable to a capture card  1102  which digitalizes the image signal and supplies it to a main storage device  1105 . 
     CPU  1104  executes functional modules made of various software stored in the main storage device  1105 . 
     An image transmission module  1203  compresses the digital image and transmits it to the client via a network card  1106 . 
     A panorama image generation module  1202  generates a panorama image from a plurality of digital images, compresses it and stores it in a disk  1108 . 
     The image transmission module  1203  transmits the panorama image stored in the disk  1108  to the client, in response to a request from the client. 
     A camera control module  1204  transfers a control command for pan/tilt/zoom or the like of the camera connected via the serial cable to thereby control it. 
     The camera control module  1204  controls the camera in response to a camera control request from the client or from the panorama image generation module. 
     The image reception client receives image data from a network card  1115  and displays it on a display device  1110 . Through GUI operation on the display device  1110 , a camera control request is transmitted to the server via the network card  1115 . 
     A CUP  1113  executes functional modules made of various software stored in a main storage device  1114 . 
     An image reception module  1207  expands a compressed image received via the network card  1115  and displays it as a moving image on the display device  1110 . 
     A camera operation module  1208  requests a panorama image from the server. The panorama image received via the network card  1115  is displayed in a window. A camera operation entered by a mouse on the display screen is supplied to the server via the network. 
     First, the panorama image generation module  1202  operating at the image transmission server will be described. 
     A panorama image is generated by setting the widest angle zoom value to the camera and sequentially taking with the camera an image in each area divided from the whole photographing area of the camera. The zoom value is set to the view angle a at the widest angle of the camera. The pan is decremented and incremented by α starting from 0 to dispersibly change it in a range not exceeding the maximum pan limit of the camera. An image is taken even at the camera maximum pan limit. 
     If the ratio of a vertical side to a horizontal side of an image is 3:4, the tilt is decremented and incremented by α×3/4 starting from 0 to dispersibly change it in a range not exceeding the maximum tilt limit of the camera. An image is taken even at the camera maximum tilt limit. 
     It is assumed for example that the camera maximum view angle is 40 degrees, the pan movable range is from −90 degrees to +90 degrees and the tilt movable range is from −30 degrees to +25 degrees. In this case, an image is taken by changing the pan angle from −90, −80, −40, 0, 40, 80, to 90, the image having a pan view angle of 40 degrees corresponding to each of the ranges of −110 to −70, −100 to −60, −60 to −20, −20 to 20, 20 to 60, 60 to 100, and 70 to 110. In this case, the image is taken by changing the tilt angle from −30, 0 to 25 for each pan angle, the image having a tilt angle of 30 degrees corresponding to each of the ranges of −45 to −15, −15 to 15, and 10 to 40. 
     The images taken at the maximum pan and tilt limits may overlap adjacent images. In this case, after the overlapped areas are cut out, the images are pasted. 
     In order to form a fine panorama image, the whole photographing area of the camera may be divided so that adjacent images have an overlapped portion. In this case, the coordinate system of each divided area is transformed into a polar coordinate system and the overlapped portions are averaged. 
     The cut and paste process described above is not intended to limit the scope of the invention. 
     Next, a visible range restricting function realized by the camera control module of the image transmission server will be described. 
     An administrator of the image transmission server is supplied with this function so that the photographing area of the camera can be restricted and the camera cannot be directed to take the image not desired to be taken. 
     The range in which the camera is allowed to take an image is called the visible range. The visible range is designated by the right and left angle limit values from the pan center and the up and down angle limit values from the tilt center. 
     The angle limit values are not the fixed limit values of pan/tilt of the camera, but are the values for designating the visible range. The parameter limit values of pan/tilt therefore change with the current zoom values. For example, if the pan limit of the visible range is 50 degrees and the zoom value of the view angle is 20 degrees, the pan angle of the camera can be set to 40 degrees at a maximum (because 40+20/2=50). If the zoom value of the view angle is 40 degrees, the pan angle of the camera can be set to 30 degrees at a maximum (because 30+40/2=50). 
     When the visible range is broadened by setting a wide angle to the camera, the camera automatically pans and tilts to direct inward. In the examples described above, under the conditions that the pan limits of the visible range is set to 50 degrees and the pan angle of the camera is 40 degrees, if the camera is zoomed out from the view angle of 20 degrees to the view angle of 40 degrees, the camera is automatically controlled to set the pan angle of 30 degrees so as not to take an image outside of the visible range. 
     Independently from pan/tilt, fixed limit values of the zoom parameters of the camera can be designated. Both the zoom limit value and wide angle limit value can be designated. The pan/tilt limit values of the visible range and the limit values of the zoom parameters have the following dependency: 
     Zoom limit≦Wide angle limit≦(pan left limit+pan right limit); and 
     Zoom limit≦Wide angle limit≦(pan up limit+pan down limit)×(4/3). 
     If the visible range of pan/tilt is set narrower, the wide angle limit is required to satisfy the above dependency, because if the wide angle is set an image outside of the visible range can be taken even if the camera is not panned or tilted. 
     With the visible range set as above, a panorama image having the pan/tilt limit values in the visible range is cut out to be used by the client to control the camera. 
     If the panorama image in the whole photographing area of the camera generated by the panorama image generation module is used even if the visible range is set, a client user can look at a scene outside of the visible range on the panorama image although it is not a live image. Furthermore, since the server administrator limits the visible range, the client user can know the limit in the visible range. The, administrator does not wish that the client user becomes conscious of the limit in the visible range set by the server administrator. The cut-out process may be performed either by the server or client. 
     With reference to FIG. 6, the cut-out process will be described. It is assumed that the cut-out process can be performed either by the server or client. 
     First, a client requests a visible range, restriction setting value from the server (S 1301 ). In response to this, the server returns the visible range restriction setting value back to the client(S 1302 ). 
     Upon reception of the visible range restriction setting value from the server, the client requests a panorama image from the server by designating a request range of the panorama image. In this case, the received visible range restriction setting value is used as the request range of the panorama image (S 1303 ). 
     If the cut-out process can be executed by the server (S 1307 ), the panorama image cut out by the server is transmitted to the client (S 1304 ), whereas if not at S 1307 , the server sends the panorama image and the angle values corresponding to the right and left and up and down ends of the panorama image, to the client. The client checks whether the received panorama image is coincident with the requested size (S 1305 ). If not, the cut-out process is executed by the client (S 1306 ). 
     If the cut-out process is executed by the server at S 1304 , the angle values corresponding to the right and left and up and down ends of the panorama image correspond to the requested size of the panorama image. 
     After the panorama image in the visible range is obtained by the processes shown in FIG. 6, a variable magnification process shown in FIGS. 7A and 7B is performed. The details of this process shown in FIGS.  7 A and  7 B will be later given. 
     On the side of the client received the panorama image in the visible range, the panorama image for the camera control shown in the lower area of FIG. 8 is displayed in a window different from a window shown in the upper area of FIG. 8 for displaying a moving image. The panorama image displayed is based upon a display size (called a base window size) of a panorama image without any visible range restriction. 
     The panorama image cut out basing upon the visible range restriction is displayed to be as equal size as possible to the base window size so that the client recognizes the visible range as less as possible. If the cut-out panorama image itself is displayed, the window size of the panorama image is changed with the visible range restriction. For example, if a client user accesses a server which changes the visible range on a day basis or accesses servers having different visible ranges at the same time, the panorama image is displayed in a different size each day or in a different size depending upon the accessed server. The client user may feel such an operation of GUI something unusual. The client user may become conscious of visible range restriction. 
     One method of displaying the panorama image to be as equal size as possible to a panorama image without any visible range restriction is to set one of the vertical and horizontal sides equal to the base window size and the other shorter than the base window size, while the vertical and horizontal side ratio is maintained constant, as shown in FIG.  7 A and FIGS. 9A to  9 C. 
     First at S 1401 , after a panorama image cut out in accordance with the visible range restriction is received, the width and height (W, H) of a predetermined display window are compared with the width and height (PW, PH) of the cut-out panorama image (S 1402 ) to check whether W/PW≧H/PH is satisfied or not (S 1403 ). 
     If satisfied at S 1403 , the cut-out panorama image is enlarged without changing the vertical and horizontal side ratio so as to make the width of the cut-out panorama image equal to the width of the display window size, and displayed on the display window (S 1404 ). 
     If not satisfied at S 1403 , the cut-out panorama image is enlarged without changing the vertical and horizontal side ratio so as to make the height of the cut-out panorama image equal to the height of the display window size, and displayed on the display window (S 1405 ). 
     FIGS. 9A to  9 C show examples of the panorama image displayed. 
     The upper area of each of FIGS. 9A to  9 C shows the screen for setting the visual range at the server, and the lower area shows the screen at the client. 
     FIG. 9A shows the screen when the visual range restriction is not performed. 
     The lower area of FIG. 9A shows a panorama image in the visible range equal to the whole photographing area of the camera. A broken line frame indicates an area in which a moving image is displayed. By moving this frame and changing the frame size, pan/tilt/zoom of the camera can be controlled. A narrow black line indicates an area in which the center of the broken line frame can be moved for zoom setting. 
     FIGS. 9B and 9C show the screen when the visual range restriction is performed. W/PW≧H/PH is satisfied in the case of FIG. 9B, whereas W/PW≧H/PH is not satisfied in the case of FIG. 9C. A bold line shown in the upper areas of FIGS. 9B and 9C indicates a visible range set by an administrator. 
     Another method of displaying the panorama image to be as equal size as possible to a panorama image without any visible range restriction is to set one of the vertical and horizontal sides equal to the base window size and the other longer than the base window size, while the vertical and horizontal side ratio is maintained constant, as shown in FIG.  7 B and FIGS. 10A to  10 C. 
     First at S 1411 , after a panorama image cut out in accordance with the visible range restriction is received, the width and height (W, H) of a predetermined display window are compared with the width and height (PW, PH) of the cut-out panorama image (S 1412 ) to check whether W/PW≧H/PH is satisfied or not (S 1413 ). 
     If satisfied at S 1413 , the cut-out panorama image is enlarged without changing the vertical and horizontal side ratio so as to make the height of the cut-out panorama image equal to the height of the display window size, and displayed on the display window (S 1414 ). 
     If not satisfied at S 1413 , the cut-out panorama image is enlarged without changing the vertical and horizontal side ratio so as to make the width of the cut-out panorama image equal to the width of the display window size, and displayed on the display window (S 1415 ). 
     Since the vertical or horizontal side of the enlarged panorama image is larger than the window size, a scroll bar is disposed one of the vertical and horizontal sides (S 1416 , S 1417 ) so that the panorama image can be scrolled in one direction. If apportion of a scope to be described later becomes invisible while the panorama image is scrolled, the panorama image is automatically scrolled to make the scope visible. 
     FIGS. 10A to  10 C show examples of the panorama image displayed. 
     The upper area of each of FIGS. 10A to  10 C shows the screen for setting the visual range at the server, and the lower area shows the screen at the client. 
     FIG. 10A shows the screen when the visual range restriction is not performed. 
     The lower area of FIG. 10A shows a panorama image in the visible range equal to the whole photographing area of the camera. A broken line frame indicates an area in which a moving image is displayed. By moving this frame and changing the frame size, pan/tilt/zoom of the camera can be controlled. A narrow line indicates an area in which the center of the broken line frame can be moved for zoom setting. 
     FIGS. 10B and 10C show the screen when the visual range restriction is performed. W/PW≧H/PH is satisfied in the case of FIG. 10B, the height of the cut-out panorama image is made equal to the height of the base window, and the scroll bar is disposed in the horizontal direction. W/PW≧H/PH is not satisfied in the case of FIG. 10C, the width of the cut-out panorama image is made equal to the width of the base window, and the scroll bar is disposed in the vertical direction. 
     A bold line shown in the upper areas of FIGS. 10B and 10C indicates a visible range set by an administrator. 
     The size of a window displayed in this manner has a fixed size. Therefore, a client user can control the camera by using the panorama image without becoming conscious of the visible range restriction. 
     On the panorama image displayed on the client side, a broken line frame is displayed which indicates a current photographing area (scope). As the camera is controlled, the scope moves in accordance with this control. A client user can control the camera by using the panorama image. 
     The following operations are possible on the panorama image. 
     “Click”: Pan/tilt is changed so that the clicked position becomes the center of pan/tilt. If a position in the scope is clicked, this position becomes the center of pan/tilt. 
     “Click position in scope and drag it with mouse”: The scope moves in accordance with the motion of the mouse. When the mouse is released, pan/tilt is changed to take an image at the scope position. 
     “Resize scope”: When a frame of the scope is clicked and dragged with a mouse, the size of the scope can be changed. In accordance with this resizing, the zoom is controlled. 
     “Draw rubber band”: When a position outside of the scope is clicked and dragged, a frame (rubber band) is drawn in accordance with the motion of the mouse. In order to use the rubber band as a new scope when the mouse is released, pan/tilt/zoom is changed. 
     If the visible range is set too narrow,the above-described algorithm makes the magnification factor too large. Therefore, the image shown in FIG. 11A is so rough that it cannot be recognized as a panorama image. In this case, the panorama image is not used as a background, but only a background color or a predetermined image is displayed to control the camera by operating the scope in the window. Alternatively, as shown in FIG. 1C, without using the enlarged image, the server may take a new panorama image corresponding to the visible range restriction. In this case, the panorama image is taken each time the visible range restriction is changed, so that the server administrator is required to perform a cumbersome work. However, the visible range restriction made too narrow is rare, and if the following automatic photographing mechanism is incorporated, such a cumbersome work is avoided. 
     Specifically, after the visible range restriction is set, the panorama image generation module is set so that it automatically operates while a client does not access. When a client accesses during photographing, the panorama image generation is cancelled to stand by until the client disconnects. In order to generate a panorama image corresponding to the visible range, an image in each divided area of the visible range is taken not by setting the view angle to the maximum zoom values but by setting the zoom values so that one of the vertical and horizontal sides of the visible range is set equal to the size of the photographing, area and the other is set shorter. In this case, one of the vertical and horizontal sides is not necessary to be photographed divisionally so that the divisional photographing is performed by changing either pan or tilt. A panorama image photographed in this manner becomes fine as shown in FIG.  11 C and the rough image such as shown in FIG. 11A is not displayed. 
     The visible range is judged as narrow if the height (vertical) or width (horizontal) of an image in the visible range is smaller than the vertical or horizontal side of an image taken at a maximum, magnification factor of the camera. This judgement may be made by comparing an area of a predetermined frame with an area of the visible range. 
     The invention is also applicable to a system having a plurality of apparatuses (e.g., a host computer, an interface apparatus, a reader, a printer and the like) or to a single apparatus (e.g., a copier, a facsimile or the like). 
     The scope of the invention contains also the case wherein software program codes realizing the function of each embodiment described above are supplied to a computer (CPU or MPU) of the apparatus or system connected to various devices realizing the embodiment function, and the computer operates the devices in accordance with the stored programs. 
     In this case, the software program code themselves realize the embodiment function. Therefore the program codes themselves and means for supplying the program codes, e.g., a storage medium storing the program codes, constitute the present invention. 
     The storage medium for storing such program codes may be a floppy disk, a hard disk, an optical disk, a magnetooptical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM or the like. 
     It is obvious that the program codes are included in the embodiment of the invention, wherein not only the computer executes the supplied program codes to realize the embodiment function but also the program codes in cooperation with an OS (operating system) running on the computer or with another application or the like realize the embodiment function. 
     It is obvious that the scope of the invention also contains the case wherein the functions of each embodiment can be realized by writing the program codes into a memory of a function expansion board inserted into a computer or of a function expansion unit connected to the computer, and thereafter by executing a portion or the whole of actual processes by a CPU of the function expansion board or function expansion unit. 
     As described so far, according to the invention, an area outside of the visible range is not displayed but only an area in the visible range is displayed to a client. Accordingly, a client is less conscious of a presence of the visible range restriction. 
     An image in the visible range is variably magnified so as to make the size near to that of the base window. It is therefore possible to make a client less conscious of a change in the size of an image displayed in the base window. 
     If one of the vertical and horizontal sides of an image in the visible range is shorter than the vertical or horizontal side of an image taken at the maximum magnification factor of the camera, the camera is controlled so that an image in the visual range is newly taken and the enlarged image of a rough quality is not displayed. 
     The invention is not limited only to the above embodiments, but various modifications are possible without departing from the scope of the appended claims.