in the following detailed description , numerous specific details are set forth in order to provide a thorough understanding of the present invention . however , it will be understood by those skilled in the art that the present invention may be practiced without these specific details . in other instances , well - known methods , procedures , and components have not been described in detail so as not to obscure the present invention . some embodiments of the present invention are directed to an in - vivo device that may be inserted into a body lumen , e . g ., the gastro - intestinal ( gi ) tract , for example , from outside the body . some embodiments are directed to a typically one time use or partially single use detection and / or analysis device . some embodiments are directed to in - vivo sensing devices that may be passed through other body lumens , for example , through blood vessels , the reproductive tract , or the like . the in - vivo device may be , for example , a sensing device , an imaging device , a diagnostic device , a detection device , an analysis device , a therapeutic device , or a combination thereof . in some embodiments , the in - vivo device may include an image sensor or an imager and / or other suitable components . some embodiments of the present invention may be directed to other imaging devices , not necessarily in - vivo imaging . controlling and positioning an in vivo imaging device , for example a swallowable imaging capsule , may be useful in certain cases . for example , when the patient complains about pain in the throat , the health care professional may want to closely examine the patient &# 39 ; s esophagus , and spend extra time around the border between the squamous lined epithelium of the esophagus and the columnar epithelium of the stomach ( the z - line ), in order to make sure it is fully viewed from several directions by the imaging device . in this case , it may be useful to stop the device at a certain point in the esophagus , for example just before the z - line , and twist or rotate it around its longitudinal axis in a circular manner in order to capture a complete view of the in vivo area . in a preferred embodiment , the images of the z - line are captured from different directions . the health care professional may wish to inspect the patient &# 39 ; s stomach , an organ which is typically much larger than the imaging device . when a capsule is moving independently with no external control , it may tumble arbitrarily around the stomach . preferably , the doctor would want to make sure that all of the stomach &# 39 ; s tissue is examined , and that images covering the whole area of interest are captured by the device . devices , systems and methods according to some embodiments of the present invention , including for example in - vivo sensing devices , receiving systems and / or display systems , may be similar to embodiments described in u . s . pat . no . 5 , 604 , 531 to iddan et al ., entitled “ in - vivo video camera system ”, and / or in u . s . pat . no . 7 , 009 , 634 to iddan et al ., entitled “ device for in - vivo imaging ”, all of which are hereby incorporated by reference in their entirety . devices , systems and methods according to some embodiments of the present invention , may be similar to embodiments described in pct patent application publication number wo2006059331 , entitled “ two - way communication in an autonomous in vivo device ”, which discloses an autonomous in - vivo sensing device that includes an in - vivo transceiver to both transmit wireless signals to for example an external receiver , and to receive wireless signals from for example an external transmitter . the application further discloses that wireless signals received by the in - vivo transceiver may be or may include command or control signals that may activate , de - activate or alter an operational state of one or more functions of the in - vivo device . the wireless signals transmitted by the in - vivo transceiver may be or include sensory data such as for example image data that may be collected by the in - vivo sensing device . devices and systems as described herein may have other configurations and / or sets of components . for example , an external receiver / recorder unit , a processor and a monitor , e . g ., in a workstation , such as those described in the above publications , may be suitable for use with some embodiments of the present invention . the present invention may be practiced using an endoscope , needle , stent , catheter , etc . some in - vivo devices may be capsule shaped , or may have other shapes , for example , a peanut shape or tubular , spherical , conical , or other suitable shapes . some embodiments of the present invention may include , for example , a typically swallowable in - vivo device . the in - vivo device need not be swallowable , and may have other shapes or configurations . some embodiments may be used in various body lumens , for example , the gi tract , blood vessels , the urinary tract , the reproductive tract , or the like . embodiments of the in - vivo device of the present invention are typically controllable by an external magnetic force . the in - vivo device may be or may include a capsule or other unit where all the components are substantially contained within a container , housing or shell , and where the in - vivo device does not require any wires or cables to , for example , receive power / commands or transmit information . the in - vivo device may communicate with an external receiving and display system to provide display of data , control , or other functions . for example , power may be provided by an internal battery or an internal power source , or using a wired or wireless power - receiving system . other embodiments may have other configurations and capabilities . for example , components may be distributed over multiple sites or units . control information or other information may typically be received from an external source . devices , systems and methods in accordance with some embodiments of the invention may be used , for example , in conjunction with a device which may be inserted into a human body or swallowed by a person . however , embodiments of the invention are not limited in this regard , and may be used , for example , in conjunction with a device which may be inserted into , or swallowed by , a non - human body or an animal body . other embodiments of the invention need not be used with in vivo imaging devices , and may be used for enhancing images obtained by other types of imaging devices , such as digital cameras , or virtual imaging devices . fig1 schematically illustrates an in - vivo system in accordance with some embodiments of the present invention . one or more components of the system may be used in conjunction with , or may be operatively associated with , the devices and / or components described herein or other in - vivo devices in accordance with embodiments of the invention . in some embodiments , the system may include a device 140 having a sensor , e . g ., an imager 146 , one or more illumination sources 142 , an optical system 150 , an internal magnet 151 , a power source 145 , and a transceiver 141 . in some embodiments , device 140 may be implemented using a swallowable capsule , but other sorts of devices or suitable implementations may be used . outside a patient &# 39 ; s body may be , for example , an external receiving unit 112 , a magnetic field generator 125 and an external capsule position control unit 122 . a storage unit 119 which may be or include for example one or more of a memory , a database , etc . or other storage systems , a processor 114 , and a monitor 118 . in some embodiments , for example , processor 114 , storage unit 119 and / or monitor 118 may be implemented as a workstation 117 , e . g ., a computer or a computing platform . transceiver 141 may operate using radio waves ; but in some embodiments , such as those where device 140 is or is included within an endoscope , transceiver 141 may transmit / receive data via , for example , wire , optical fiber and / or other suitable methods . other known wireless methods of transmission may be used . transceiver 141 may include , for example , a transmitter module or sub - unit and a receiver module or sub - unit , or an integrated transceiver or transmitter - receiver . in one embodiment , transceiver 141 includes at least a modulator for receiving an image signal from the sensor 146 , a radio frequency ( rf ) amplifier , an impedance matcher and an antenna 148 . the modulator converts the input image signal having a cutoff frequency f c of less than 5 mhz to an rf signal having a carrier frequency f r , typically in the range of 1 ghz . while in one embodiment , the signal is an analog signal , the modulating signal may be digital rather than analog . the carrier frequency may be in other bands , e . g . a 400 mhz band . the modulated rf signal has a bandwidth of f t . the impedance matcher matches the impedance of the circuit to that of the antenna . other transceivers or arrangements of transceiver components may be used . for example , alternate embodiments may not include a matched antenna or may include a transceiver without a matching circuit . in alternate embodiments , the device 140 may have different configurations and include other sets of components . other frequencies may be used . in yet further embodiments , sensors other than image sensors may be used , such as ph meters , temperature sensors , pressure sensors , etc . and input rf signals other than image signals may be used . the transceiver 141 may send different types of signals , including for example telemetry signals , image signals and beacon signals . other types of signals may be transmitted by transceiver 141 . the signal types may vary in several parameters , such as the length of the signal burst , the transmission frequency of the signal , the rate of sending the signal , the power used to transmit the signal , the content of the sent signal , etc . information sent from the device 140 may include information sensed by sensors in the device such as images , ph , temperature , location and pressure . information sent from the device 140 may include telemetry information , regarding the capsule id , time counter , image type data and the status of components in the device , such as current image capturing mode of the imager or estimated remaining power of the device power source . the signals may be sent separately or as part as a larger frame , for example a frame including both telemetry - type and image - type signals . beacon signals may typically be transmitted separately , and not in a frame which may include image data or other types of signals . device 140 typically may be or may include an autonomous swallowable capsule , but device 140 may have other shapes and need not be swallowable or autonomous . embodiments of device 140 are typically autonomous , and are typically self - contained . for example , device 140 may be a capsule or other unit where all the components are substantially contained within a container or shell , and where device 140 does not require any wires or cables to , for example , receive power or transmit information . in some embodiments , device 140 may be autonomous and non - remote - controllable ; in another embodiment , device 140 may be partially or entirely remote - controllable . in some embodiments , device 140 may include an in - vivo video camera , for example , imager 146 , which may capture and transmit images of , for example , the gi tract while device 140 passes through the gi lumen . other lumens and / or body cavities may be imaged and / or sensed by device 140 . in some embodiments , imager 146 may include , for example , a charge coupled device ( ccd ) camera or imager , a complementary metal oxide semiconductor ( cmos ) camera or imager , a digital camera , a stills camera , a video camera , or other suitable imagers , cameras , or image acquisition components . in some embodiments , imager 146 in device 140 may be operationally connected to transceiver 141 . transceiver 141 may transmit images to , for example , external transceiver or receiver / recorder 112 ( e . g ., through one or more antennas ), which may send the data to processor 114 and / or to storage unit 119 . transceiver 141 may also include control capability , although control capability may be included in a separate component , e . g ., processor 147 . transceiver 141 may include any suitable transmitter able to transmit image data , other sensed data , and / or other data ( e . g ., control data , beacon signal , etc .) to a receiving device . transceiver 141 may also be capable of receiving signals / commands , for example from an external transceiver . for example , in some embodiments , transceiver 141 may include an ultra low power radio frequency ( rf ) high bandwidth transmitter , possibly provided in chip scale package ( csp ). in some embodiments , transceiver 141 may transmit / receive via antenna 148 . transceiver 141 and / or another unit in device 140 , e . g ., a controller or processor 147 , may include control capability , for example , one or more control modules , processing module , circuitry and / or functionality for controlling device 140 , for controlling the operational mode or settings of device 140 , and / or for performing control operations or processing operations within device 140 . according to some embodiments , transceiver 141 may include a receiver which may receive signals ( e . g ., from outside the patient &# 39 ; s body ), for example , through antenna 148 or through a different antenna or receiving element . according to some embodiments , signals or data may be received by a separate receiving component in device 140 . power source 145 may include one or more batteries or power cells . for example , power source 145 may include silver oxide batteries , lithium batteries , other suitable electrochemical cells having a high energy density , or the like . other suitable power sources may be used . for example , power source 145 may receive power or energy from an external power source ( e . g ., an electromagnetic field generator ), which may be used to transmit power or energy to in - vivo device 140 . optionally , in some embodiments , transceiver 141 may include a processing unit , processor or controller , for example , to process signals and / or data generated by imager 146 . in another embodiment , the processing unit may be implemented using a separate component within device 140 , e . g ., controller or processor 147 , or may be implemented as an integral part of imager 146 , transceiver 141 , or another component , or may not be needed . the processing unit may include , for example , a central processing unit ( cpu ), a digital signal processor ( dsp ), a microprocessor , a controller , a chip , a microchip , a controller , circuitry , an integrated circuit ( ic ), an application - specific integrated circuit ( asic ), or any other suitable multi - purpose or specific processor , controller , circuitry or circuit . in some embodiments , for example , the processing unit or controller may be embedded in or integrated with transceiver 141 , and may be implemented , for example , using an asic . in some embodiments , imager 146 may acquire in - vivo images continuously , substantially continuously , or in a non - discrete manner , for example , not necessarily upon - demand , or not necessarily upon a triggering event or an external activation or external excitation , or in a periodic manner , an intermittent manner , or an otherwise non - continuous manner . in some embodiments , device 140 may include one or more illumination sources 142 , for example one or more light emitting diodes ( leds ), “ white leds ”, or other suitable light sources . illumination sources 142 may , for example , illuminate a body lumen or cavity being imaged and / or sensed . an optical system 150 , including , for example , one or more optical elements , such as one or more lenses or composite lens assemblies , one or more suitable optical filters , or any other suitable optical elements , may optionally be included in device 140 and may aid in focusing reflected light onto imager 146 , focusing illuminating light , and / or performing other light processing operations . in a preferred embodiment , device 140 may include a magnetic element 151 . the magnetic element may be cylindrically - shaped , oval , or spherical . other shapes may be used , for example a cubic magnet . preferably , the magnetic element may be positioned inside the capsule &# 39 ; s shell , adjacent to or near the capsule &# 39 ; s inner wall or inner side of its shell . such positioning may prevent injury of the tissue when the device is maneuvered by external forces , and may by advantageous for the maneuvering process itself since the control of the capsule may be more precise . magnetic field generator 125 may produce a magnetic force , for example to exert a moment force on the magnet 151 located in the in vivo device , thereby causing the in vivo device to be maneuvered in the somersault manner described below . a position control unit 122 may be used to control the strength and direction of the magnetic field generator 125 , according to the direction that the user may want to maneuver the device . the magnetic field generator 125 may be included in a mobile unit , for example a hand - held unit , that may be movable by a health care specialist adjacent a patient &# 39 ; s body , in order to control the position of the in vivo device while it is in vivo . according to some embodiments the position control unit 122 may operate by getting feedback from the device 140 , for example , feedback based on image analysis or analysis of input from sensors other than an image sensor that may be included in device 140 . based on image analysis ( or for example pressure data analysis or temperature data analysis ) the position control unit 122 or any other suitable processor which may be in communication with position control unit 122 , may cause changes in the external magnetic field that may stop or spin or otherwise automatically control movement of the device 140 . in some embodiments , the components of device 140 may be enclosed within a housing or shell , e . g ., capsule - shaped , oval , or having other suitable shapes . the housing or shell may be substantially transparent , and / or may include one or more portions , windows or domes that may be substantially transparent . for example , one or more illumination source ( s ) 142 within device 140 may illuminate a body lumen through a transparent , window or dome ; and light reflected from the body lumen may enter the device 140 , for example , through the same transparent or portion , window or dome , or , optionally , through another transparent portion , window or dome , and may be received by optical system 150 and / or imager 146 . in some embodiments , for example , optical system 150 and / or imager 146 may receive light , reflected from a body lumen , through the same window or dome through which illumination source ( s ) 142 illuminate the body lumen . according to one embodiment , while device 140 traverses a patient &# 39 ; s gi tract , the device 140 transmits image and possibly other data to components located outside the patient &# 39 ; s body , which receive and process the data . typically , receiving unit 112 is located outside the patient &# 39 ; s body in one or more locations . the receiving unit 112 may typically include , or be operatively associated with , for example , one or more antennas , or an antenna array ( not shown ), for receiving and / or transmitting signals from / to device 140 . receiving unit 112 typically includes an image receiver storage unit . according to one embodiment , the image receiver 112 and image receiver storage unit are small and portable , and are typically worn on the patient &# 39 ; s body ( or located in close proximity to the patient &# 39 ; s body ) during recording of the images , at least until the image capturing procedure is determined to be terminated . in some embodiments , device 140 may communicate with an external receiving and display system ( e . g ., workstation 117 or monitor 118 ) to provide display of data , control , or other functions . for example , power may be provided to device 140 using an internal battery , an internal power source , or a wireless system able to receive power . other embodiments may have other configurations and capabilities . for example , components may be distributed over multiple sites or units , and control information or other information may be received from an external source . processor 114 may include a processing unit , processor or controller . the processing unit may include , for example , a cpu , a dsp , a microprocessor , a controller , a chip , a microchip , a controller , circuitry , an ic , an asic , or any other suitable multi - purpose or specific processor , controller , circuitry or circuit . data processor 114 may analyze the data received via external receiver / recorder 112 from device 140 , and may be in communication with storage unit 119 , e . g ., transferring frame data to and from storage unit 119 . data processor 114 may provide the analyzed data to monitor 118 , where a user ( e . g ., a physician ) may view or otherwise use the data . in some embodiments , data processor 114 may be configured for real time processing and / or for post processing to be performed and / or viewed at a later time . in the case that control capability ( e . g ., delay , timing , etc ) is external to device 140 , a suitable external device ( such as , for example , data processor 114 or external receiver / recorder 112 having a transmitter or transceiver ) may transmit one or more control signals to device 140 . monitor 118 may include , for example , one or more screens , monitors , or suitable display units . monitor 118 , for example , may display one or more images or a stream of images captured and / or transmitted by device 140 , e . g ., images of the gi tract or of other imaged body lumen or cavity . additionally or alternatively , monitor 118 may display , for example , control data , location or position data ( e . g ., data describing or indicating the location or the relative location of device 140 ), orientation data , and various other suitable data . in some embodiments , for example , both an image and its position ( e . g ., relative to the body lumen being imaged ) or location may be presented using monitor 118 and / or may be stored using storage unit 119 . other systems and methods of storing and / or displaying collected image data and / or other data may be used . typically , device 140 may transmit image information in discrete portions . each portion may typically correspond to an image or a frame ; other suitable transmission methods may be used . for example , in some embodiments , device 140 may capture and / or acquire an image once every half second , and may transmit the image data to the external receiving unit 112 . other constant and / or variable capture rates and / or transmission rates may be used . in prior solutions , the device may be moved along the body lumen , for example pulled in the direction of the gradient vector of the external magnetic force . such type of movement may injure the delicate tissue wall . when placed in a magnetic field , magnetic dipoles typically align their axes to be parallel with the field line . in a method according to an embodiment of the invention a permanent magnet or other suitable component having a magnetic dipole , which is placed within or on an in vivo device , when placed in a rotating magnetic field , will typically rotate so as to maintain alignment with the field . the rotating motion of the magnet will cause the device body to rotate with it , enabling the device to progress through a body lumen in a rotating , typically head to toe or somersaulting motion . according to one embodiment the rotating motion is caused by a n / s rotation of a magnet outside a patient &# 39 ; s body . according to other embodiments the rotating magnetic field may be produced by other means , such as a rotating magnetic field generator . thus control of the rotating field may be manual or without manual intervention . referring to fig2 , according to an embodiment of the present invention , the device is preferably rolled around its center of mass , in a somersault manner , and the movement of the capsule is performed by head - to - tail rolling along the longitudinal axis of the device , instead of dragging or pulling it along the lumen without rotation . according to some embodiments rolling or a somersaulting motion of the device is most effective in voluminous lumens , such as the stomach or colon . such motion of a device may also be used in tube like lumens , such as the esophagus . for example , as shown in fig2 , the capsule may initially be positioned at p 1 in a certain orientation , then may be rolled around its longitudinal axis to position and orientation p 2 , then p 3 . such movement may reduce the risk of injured tissue , since the device does not graze the tissue of the walls or rub against it . to achieve such manner of movement , the position of the internal magnet or magnets within the device may preferably be away from the center of mass of the device . the center of mass is typically calculated without the magnets &# 39 ; addition , and the magnets are positioned on one side of the center of mass , in order to create an asymmetrical center of mass in the capsule . for example , in a device with a single imaging head , the magnet may be positioned on the side of the device which is near the imager . in another embodiment , the device may have two imagers , for example one on each side of the longitudinal axis of the device . the two imagers may have different functional capabilities . one imager may be narrowly focused for viewing the near tissue , and the other may be configured for imaging a wider field of view . in such embodiments , the magnet may be positioned on the side of the imager with the narrow field of view , focused on the near tissue , in order that the center of mass may be located closer to that side , and the device may rest on the tissue as a result . in another embodiment , the device may have one type of sensor , i . e . an imager , on one side , and another type of sensor on the other side , i . e . a pressure sensor , a ph sensor or an image sensor accompanied by an optical system to perform an optical biopsy . the magnet may typically be positioned near the side of the device which may functionally be required to be positioned closer to the gi tract wall tissue . reference is now made to fig3 a , 3 b and 3 c , which are schematic side view illustrations of an in vivo imaging device according to three different embodiments of the invention . in all these embodiments , the device changes position and / or orientation by applying an external moment force , which causes the somersault - type movement , rather than applying an external gradient force which creates the pulling movement and may injure the tissue . the moment force may be created around the center of gravity of the device . according to an embodiment of the invention , the magnetic force applied to create a moment force that may move the device may be weaker than the force required to move the capsule in a certain gradient . therefore , embodiments of the invention may be advantageous in energy consumption . in the first embodiment , fig3 a shows the in vivo imaging device with the center of mass marked by point g . typically , the position of the magnet affects the center of mass of the device , and is chosen to be on the side of the device which needs to be closer to the tissue . for example , in one embodiment , the imager needs to be close to the tissue in order to enable optical biopsy functionality . the location of the device &# 39 ; s center of gravity ( and the magnet ) will be selected as the side with the optical biopsy imager . in another embodiment , the device may be configured for performing a thorough scanning of the stomach , as will be described in fig3 hereinbelow . fig3 b shows another embodiment of the magnetic elements within the capsule device . fig3 c illustrates a third embodiment according to the invention . in this embodiment , the in vivo device includes a tube element which may hold the magnet . the tube can be positioned along a longitudinal axis of the device , but can also be positioned diagonally or along latitudinal axis . the magnet element placed within the tube can move freely from one side of the tube to the other . the device &# 39 ; s center of gravity , g , may also change with the movement of the magnet element . in this embodiment , the center of gravity of the in vivo device may be controlled externally by changing the direction or the intensity of the external magnetic field . the field of view of the device may be controlled externally by the magnetic field . reference is now made to fig4 , which illustrates an exemplary movement of the in vivo imaging device in a relatively large organ such as the stomach . the center of gravity may be selected to be on the side of the device which is opposite the imaging side , and the device may be controlled to move the imaging head in a circular manner in order to cover the whole organ . the heavier side of the device , which is the side of the center of gravity , may be the side of the magnet placement . in a preferred embodiment , this side of the device may be close to the tissue or may rest on it as shown in the embodiments of fig3 a - c , and may be positioned in a specific spot in the organ . the imaging head position may be controlled externally by the magnetic field generated by magnetic field generator 125 and controlled to a certain wanted position by position control unit 122 . for example , the device may be controlled to move in a circular manner , in order to cover 360 ° and obtain a complete view of the organ . another embodiment which may use a similar configuration is a device which is configured to catch bio - markers . the wider span of motion performed by the lighter side of the device may be used to attract bio - markers , thereby increasing the chance of catching the biomarker during the procedure .