Abstract:
An automatically switched camera system includes sensors for providing data of an image scene having subjects who are behaving in a manner which make them potential targets of the camera system, a pre-take indicator for providing an advanced notification to the subjects of the image scene that one of them is about to become a target of the camera system, a multimodal image analysis module communicating with the sensors and the pre-take indicator, for analyzing the data of the image scene provided by the sensors to select one of the subjects as a target of the camera system and outputting an indicator function command that causes the pre-take indicator to provide the advanced notification to the selected subject.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to camera systems, and more particularly, to an automatically switched camera system having a pre-take indicator for notifying the next subject of the camera system that he or she is about to become the center or attention of the camera system.  
         BACKGROUND OF THE INVENTION  
         [0002]    Automatically switched camera systems (ASCS) have mechanical or electronic pan, tilt, zoom video cameras and heuristic means for deciding when to move the camera, i.e., pan, tilt, and/or zoom the camera, in response to audio or some other automatic driving mechanism. Typical ASCSs employ audio driving mechanisms which are implemented with one or more microphones. An ASCS driven by an audio driving mechanism pans, tilts, and/or zooms the camera toward the sound of a speaker&#39;s voice. For a more detailed description of an ASCS, see commonly-assigned, copending U.S. patent application Ser. No. ______, entitled “Method and Apparatus for Determining Camera Movement Control Criteria”, filed ______.  
           [0003]    Existing ASCSs, used in applications such as videoconferencing, include various means for indicating who the current or main subject of the ASCS is. For example, the current or main subject can be displayed in a monitor or a picture-in-picture window within a main video conference display. The current or main subject can also be indicated by the turning the mechanical or electronic pan-tilt-zoom camera of the ASCS in the direction of the subject.  
           [0004]    Although existing ASCSs indicate who the current or main subject is, such systems do not provide any type of indication of who the next subject will be. This drawback makes it virtually impossible for the next subject to prepare to become the focus of attention of the ASCS or alter their behavior so that they do not become the focus of attention of the ASCS.  
           [0005]    Accordingly, an ASCS is needed which is capable of notifying the next subject of the system that he or she is about to be focused on.  
         SUMMARY OF THE INVENTION  
         [0006]    An automatically switched camera system is disclosed herein that is capable of notifying the next subject of the system that he or she is about to be focused or targeted on by the system. The camera system comprises sensor means for providing data of an image scene having subjects who are behaving in a manner which make them potential targets of the camera system, indicating means for providing an advanced notification to the subjects of the image scene that one of them is about to become a target of the camera system, image scene analyzing means communicating with the sensor and the indicating means, for analyzing the data of the image scene provided by the sensor means to select one of the subjects as a target of the camera system and outputting an indicator function command that causes the indicating means to provide the advanced notification to the selected subject. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The advantages, nature, and various additional features of the invention will appear more fully upon consideration of the illustrative embodiments now to be described in detail in connection with accompanying drawings where like numerals are used to identify like elements and wherein:  
         [0008]    [0008]FIG. 1 is a block diagram of an ASCS, according to an exemplary embodiment of the present invention; and  
         [0009]    [0009]FIG. 2 is a block diagram showing the operation of the ASCS of the invention. 
     
    
       [0010]    It should be understood that the drawings are for purposes of illustrating the concepts of the invention and are not necessarily to scale.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    The present invention is an ASCS that includes a pre-take indicator for notifying the next subject of the ASCS that he or she is about to be focused or targeted on. FIG. 1 is a block diagram of an ASCS  10 , according to an exemplary embodiment of the present invention. The ASCS  10  generally comprises a video camera  12 , a camera controller  14 , a multimodal image analysis module  16 , a timer  18 , a pre-take indicator  20  and a pre-take indicator controller  22 .  
         [0012]    The video camera  12  is used in the ASCS  10  for sensing subjects in an image scene by obtaining a video of the scene. The video camera  12  may be a mechanical pan, tilt, zoom camera or an electronic pan, tilt, zoom camera. Both types of video cameras are well known in the art and therefore, no further discussion of these devices are needed here. The video camera  12  typically includes a microphone  24  for sensing audio produced by the subjects in the image scene. One or more separate microphones (not shown) may also be utiltized in the ASCS  10  in lieu of, or in addition to the microphone  24  of the camera  12 . The image scene data sensed by the camera  12  and the microphone(s)  24  is inputted into the multimodal image analysis module  16 .  
         [0013]    The camera controller  14  receives camera function instructions or commands from the multimodal image analysis module  16 , and in response thereto, causes the video camera  12  to pan, tilt, and/or zoom to focus on the main (target) subject of the image scene. The camera controller  14  may be implemented using well known microprocessor or like devices.  
         [0014]    The pre-take indicator  20  shows or alerts the next subject of the ASCS  10  that he or she is about to become the focus of attention or target of the ASCS  10 . Accordingly, this person can prepare him- or herself to become the target of the ASCS  10 , or alter their behavior so that they do not become the target of the ASCS  10 . The pre-take indicator  20  can be embodied in any suitable form that is capable of notifying a next subject that he or she is about to become the target of the ASCS  10 . By way of example and not limitation, the pre-take indicator  20  may be embodied as a light indicator, an audio indicator, or a PIP display on a main display screen of the ASCS  10 .  
         [0015]    The pre-take indicator  20  exemplified in FIG. 1 comprises an anthropomorphic device having a head  26  pivotally disposed on a base  28 . The head  26  includes a housing  30  having an LCD  32  embedded therein. A face-like image is generated by the head  26  when images of facial features are displayed on the LCD  32 . The pre-take indicator controller  22  receives indicator function instructions or commands from the multimodal image analysis module  16 , and in response thereto, causes the head of the pre-take indicator  20  to pivot relative to the base  28  and activates the LCD  32  to display the facial images.The pre-take indicator controller  22  may be implemented using well known microprocessor or like devices.  
         [0016]    The anthropomorphic pre-take indicator  20  of FIG. 1 operates to notify a “next” subject that he or she is about to become the target of the ASCS  10 , by immediately pivoting the head  26  to the subject and “looking” at him or her a predetermined time period before the system focuses on the subject. During this predetermined time period, the subject may prepare for becoming the target of the ASCS  10 , or modify his or her behavior in manner which will prevent becoming the target of the ASCS  10 .  
         [0017]    Still referring to FIG. 1, the timer  18  measures the amount of time a potential subject of the ASCS  10  is doing behavior (talking, moving, etc.) that would cause him or her to become the target of the ASCS  10 . If this subject performs this behavior for a predetermined amount of time, the timer  18  communicates this data to the multimodal image analysis module  16 .  
         [0018]    The multimodal image analysis module  16  includes means for processing the image scene data received from the camera  12  and microphone  24 , and the time data received from the timer  18 , to output commands or instructions to the camera controller  14  that causes the video camera  12  to focus on a particular subject-target, via panning, tilting and zooming of the camera  12 , who is behaving in a manner that is desired to be observed by the ASCS  10 . The module  16  also uses the processed image scene and time data to output commands or instructions for activating the pre-take indicator  20 . Such processing means are described in detail in the earlier-mentioned U.S. patent application Ser. No. _____, the disclosure of which is incorporated herein by reference.  
         [0019]    [0019]FIG. 2 is a block diagram showing the operation of the ASCS  10  of the invention. In block  100 , the multimode image analysis module  16  selects a subject, i.e., an initial or current target, in the image scene obtained by the video camera  12  and microphone  24 . This selection may be made arbitrarily or be based on the behavior of the subject (the behavior being of the type which would cause the subject to be a target of the ASCS  10 ). In block  102 , the sensor data (image scene data) generated by the video camera  12 , the microphone(s)  14  and the timer  18  are inputted to the multimodal image analysis module  16 . The multimodal image analysis module  16  correlates the sensor data in block  103 , analyzes the correlated data in block  104 , to score all potential targets in block  105 .  
         [0020]    In block  106 , the multimodal image analysis module  16  determines the best target based on the score calculated in block  105 . In decision block  107 , if the current target is the best target, i.e., the target performing a behavior most desired by the ASCS  10 , then the process of blocks  102 - 107  are repeated. If the current target is not the best target in block  107 , then in decision block  108 , the next target is evaluated to determine if it is the best target. If the next target is determined to be the best target in block  108 , then the total time of the next target&#39;s behavior is calculated by the module  16  in block  109 . If the next target is determined to not be the best target in block  108 , then a timestamp indicating the start time of the next target&#39;s behavior is stored in block  114 , and the total time of the next target&#39;s behavior is calculated in block  109 . The total time of the next target&#39;s behavior may be calculated by subtracting the start time of the next target&#39;s behavior from the current time.  
         [0021]    In decision block  110 , if the total time of the next target&#39;s behavior is determined by the multimode image analysis module  16  to be greater than a predetermined time threshold for switching to another target, the module  16  in block  111  outputs instructions to the camera controller  14  to move the video camera  12  to the next target. If in decision block  110 , the total time of the next target&#39;s behavior is less than the predetermined time threshold for switching to another target, the module  16  outputs instructions in block  112  to the pre-take indicator controller  22  to move the pre-take indicator  20  to the next target.  
         [0022]    While the foregoing invention has been described with reference to the above embodiment, various modifications and changes can be made without departing from the spirit of the invention. Accordingly, all such modifications and changes are considered to be within the scope of the appended claims.