Patent Publication Number: US-2023164437-A1

Title: Optical image stabilization in a scanning folded camera

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 of international application PCT/IB2021/056617 filed Jul. 22, 2021, and is related to and claims the benefit of priority from U.S. provisional patent application No. 63/064,565 filed Aug. 12, 2020, which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     Examples disclosed herein relate in general to digital cameras and in particular to correction of images obtained with folded digital cameras. 
     BACKGROUND 
     Compact digital cameras having folded optics, also referred to as “folded cameras” are known, see e.g. co-owned international patent application PCT/IB2016/057366. In handheld electronic devices (also referred to herein as “handheld devices”) such as smartphones, tablets etc. a folded Tele camera is often part of a multi-camera and accompanied by one or more additional cameras, e.g. an Ultra-wide camera and a Wide camera. An Ultra-wide camera has a larger field of view (FOV UW ) than a Wide camera, which has a larger FOV W  than a Tele camera having FOV T  (assuming similar image sensor sizes). 
       FIG.  1 A  shows schematically a folded Tele camera numbered  100  from a perspective view. Camera  100  includes a lens  102  with a lens optical axis  110 , an optical path folding element (OPFE)  104  and an image sensor  106 . OPFE  104  folds a first optical path along an axis  108  substantially parallel to the X axis from an object, scene or panoramic view section  114  into a second optical path along an axis  110  substantially parallel to the Z axis. Camera  100  is designed to rotate OPFE  104  around axis  110  (the X axis) relative to the image sensor, i.e. in the Y-Z plane, a rotation indicated by an arrow  112 . That is, folded Tele camera  100  is a “scanning” Tele camera (“STC”).  FIG.  1 B  shows OPFE  104  after rotation by 30 degrees from the zero position. 
       FIG.  1 C  shows a handheld device  120  including a STC  100  having lens  102 , OPFE  104  and image sensor  106  in a top view. A device normal (“N”) is orthogonal to a screen  116  of device  120  and points towards the observer. The camera&#39;s optical axis is parallel to the X axis. In other examples, STC  100  may be included in  120  so that the camera&#39;s optical axis is parallel to the Y axis. 
     Images are acquired from a certain point of view (POV) of a camera. The POV is the direction defined by the vector that has the location of a camera&#39;s aperture as starting point and an object point at the center of the FOV as end point (see  FIG.  3 A , with two POV vectors  324  and  328  corresponding to two FOV T     S      326  and  332 ). Instead of POV vector, one may also speak of the FOV center direction vector (FOVCD). As an example, in spherical coordinates (r, θ, φ) defined according to the ISO convention, the POV for a camera at r=0 is defined by ( 1 , θ, φ), with the polar angle θ and azimuthal angle φ defining the location of the object point at the center of the Tele FOV. The length of the POV vector may be 1 (unit vector) or may have some constant length (e.g. EFL) or may have a varying length e.g. so that it comes to lie on a specific plane. 
     As e.g. described in the co-owned PCT Patent Application No. PCT/ IB2016/057366 and with reference to  FIGS.  1 A- 1 B , rotation of the OPFE may be performed around the X axis and around the Y axis for “scanning” with the FOV in 2 dimensions (2D) in  FIGS.  1 A- 1 B . 
     Modern cameras that are included in handheld devices often include optical image stabilization (OIS) for mitigating undesired camera motion caused by a user&#39;s hand motion (often referred to as “hand-shake”). For OIS, optical components are moved to reduce movements of imaged objects on a camera&#39;s image sensor. The lens module and/or the image sensor and/or the OPFE and/or the entire camera can be moved. An inertial measurement unit (IMU) included in the handheld device provides motion data along  6  degrees of freedom, namely and with reference to  FIG.  1 C , linear movements in X-Y-Z, roll “tilt about” (or “tilt around”) the Z axis, yaw (tilt around the Y axis) and pitch (tilt around the X axis). Usually, OIS is provided for Pitch and Yaw rotation compensation only, and not for roll rotation, as Pitch and Yaw rotation account for the major share of image deterioration caused by hand-shake. Coordinate systems of the IMU, of a regular (i.e. a non-scanning) camera and of the including handheld device can be aligned and do not evolve in time. For a STC, this is not valid. The relation between a handheld device&#39;s coordinate system and that of a STC does change when FOV scanning is performed. Therefore, OIS as known in the art cannot be used for hand motion compensation in a STC. 
     There is a need for and it would be advantageous to have OIS for scanning Tele cameras. 
     SUMMARY 
     Henceforth and for simplicity, the terms “electronic device”, “electronic handheld device” “handheld device” or just “device” are used interchangeably. Henceforth and for simplicity, the term “smartphone” may be used to represent all electronic handheld devices having scanning folded cameras and implementing methods for OIS in such cameras described herein. 
     In various embodiments, there are provided Tele folded cameras operative to compensate for an undesired rotational motion of a handheld electronic device that includes such a camera, wherein the compensation depends on the undesired rotational motion and on a point of view of the Tele folded camera. 
     In various embodiments, a handheld electronic device comprises: a Tele folded camera comprising an OPFE for folding light from a first optical path that forms an angle of less than 90 degrees to a normal of the device toward a second optical path substantially orthogonal to the normal of the device, a lens with a lens optical axis along the second optical path, and an image sensor, wherein the device is a handheld electronic device; an OPFE actuator for tilting the OPFE in one or more directions to direct a point of view (POV) of the Tele folded camera towards a segment of a scene; a motion sensor for sensing an undesired rotational motion of the device; and 
     at least one actuator for moving at least one component of the Tele folded camera to compensate for the undesired rotational motion of the device, wherein the compensation depends on the undesired rotational motion of the device and on the Tele folded camera POV. 
     In some embodiments, the undesired rotation motion is around the device normal. 
     In some embodiments, a device further comprises a Wide camera having a field of view FOVw larger than a field of view FOV T  of the Tele camera. 
     In some embodiments, the sensing the rotational motion includes measuring the rotation motion in three directions. 
     In some embodiments, the actuator for moving the component of the Tele folded camera to compensate for the device&#39;s undesired rotational motion is the OPFE actuator for tilting the OPFE in one or more directions to direct a point of view (POV) of the Tele folded camera towards a segment of a scene. 
     In some embodiments, the moving of the component of the Tele folded camera to compensate for the device&#39;s undesired rotational motion includes moving the lens. 
     In some embodiments, the moving of the component of the Tele folded camera to compensate for the device&#39;s undesired rotational motion includes moving the image sensor. 
     In some embodiments, a device further comprises a processing unit configured to perform a coordinate transformation to align coordinates of the Tele camera with coordinates of the handheld device or vice versa. 
     In some embodiments, a device further comprises a processing unit configured to perform a coordinate transformation that aligns coordinates of a reference coordinate system with coordinates of the handheld device and coordinates of the Tele camera. 
     In some embodiments, the coordinate transformation is performed using Rodrigues&#39; rotation formula. 
     In some embodiments, the motion sensor includes an inertial measurement unit (IMU). 
     In some embodiments, a device further comprises a microcontroller unit (MCU) configured to read out the motion sensor and to provide control signal to the rotational motion compensation actuator. In some embodiments, the MCU is included in an application processor (AP). 
     In some embodiments, a device further comprises an application processor configured to provide POV control signal to the OPFE actuator for tilting the OPFE. 
     In various embodiments, there are provided methods comprising: providing a handheld device comprising a Tele folded camera that includes an OPFE for folding light from a first optical axis that forms an angle of less than 90 degrees to a normal of the device toward a second optical axis substantially orthogonal to a normal of the device, a lens with a lens axis along the second optical axis, and an image sensor; providing an OPFE actuator for tilting the OPFE in one or more directions to direct a point of view (POV) of the Tele folded camera towards a segment of a scene; sensing an undesired rotational motion of the device; and compensating for the undesired rotational motion, wherein the compensation depends on the undesired rotational motion and on the Tele folded camera&#39;s POV. 
     In some embodiments, the compensating for the undesired rotational motion includes moving a component of the Tele folded camera. 
     In some embodiments, the compensating for the undesired rotational motion includes compensating for a rotational motion around the device&#39;s normal direction. 
     In some embodiments, a method further comprises performing a coordinate transformation to align coordinates of the Tele camera with coordinates of an IMU. 
     In some embodiments, a method further comprises performing a coordinate transformation to coordinates of the IMU with coordinates of the Tele camera. 
     In some embodiments, a method further comprises performing a coordinate transformation to align coordinates of a reference coordinate system with coordinates of the IMU and coordinates of the Tele camera. 
     In some embodiments, the performing the coordinate transformation includes performing the transformation using Rodrigues&#39; rotation formula. 
     In some embodiments, the sensing an undesired rotational motion of the device includes sensing the undesired rotational motion in three directions. 
     In some embodiments, the compensating for the undesired rotational motion of the device includes rotating the OPFE. 
     In some embodiments, the compensating for the undesired rotational motion of the device includes moving the lens. 
     In some embodiments, the compensating for the undesired rotational motion of the device includes moving the image sensor. 
     In some embodiments, the compensating for the undesired rotational motion includes calculating a changed POV caused by the undesired rotational motion in the X direction by using the equation: P F   P =(P I ·cos(hnd_pitch)+cross(P I , R P )·sin(hnd_pitch)+R P ·(dot(P I , R P ) (1-cos (hnd_pitch)))). 
     In some embodiments, the compensating for the undesired rotational motion includes calculating a changed POV caused by the undesired rotational motion in the Y direction by using the equation: P F   Y =(P I ·cos(hnd_yaw)+cross(P I , R Y )·sin(hnd_yaw)+R Y ·(dot(P I , R Y ).(1-cos (hnd_yaw)))). 
     In some embodiments, the compensating for the undesired rotational motion includes calculating a changed POVcaused by the undesired rotational motion in the X direction by using the equation: P F   R =(P I ·cos(hnd_roll)+cross(P I , R R )·sin(hnd_roll)+R R ·(dot(P I , R R ).(1-cos (hnd_roll)))). 
     In some embodiments, the compensating for the undesired rotational motion includes calculating a direction of a changed POV caused by the undesired rotational motion in X, Y and Z direction together by using the equation: P F ,=P I +(P I -P F   P )+(P I -P F   Y )+(P I -P F   R ). 
     In some embodiments, the compensating for the undesired rotational motion includes calculating a vector of a changed POV caused by by the undesired rotational motion in X, Y and Z direction together by using the equation: P F ′P F ′.EFL T /P F ′ z . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting examples of embodiments disclosed herein are described below with reference to figures attached hereto that are listed following this paragraph. The drawings and descriptions are meant to illuminate and clarify embodiments disclosed herein, and should not be considered limiting in any way. Like elements in different drawings may be indicated like numerals. 
         FIG.  1 A  shows schematically a known folded scanning camera from a perspective view; 
         FIG.  1 B  shows the OPFE in the Tele camera of  FIG.  1 A  after rotation by 30 degrees from a zero position; 
         FIG.  1 C  shows a scanning camera such as shown in  FIGS.  1 A-B  integrated as a “rear” or “world-facing” camera in a smartphone; 
         FIG.  2 A  shows exemplarily a smartphone including a first, scanning Tele camera at a zero position, as well as a second, Wide camera; 
         FIG.  2 B  shows the smartphone of  FIG.  2 A  with the Tele camera at a non-zero position; 
         FIG.  2 C  shows the smartphone of  FIG.  2 A  with the Tele camera at another non-zero position; 
         FIG.  3 A  shows a  2 -dimensional ( 2 D) chart used to derive a coordinate system for the Tele camera; 
         FIG.  3 B  shows impact of rotational device motion caused by hand shake on the  2 D chart of  FIG.  3 A ; 
         FIG.  3 C  shows in a flow chart main steps of a method for scanning Tele camera OIS disclosed herein; 
         FIG.  4 A  shows schematically in a block diagram an embodiment of a handheld device that includes multi-aperture cameras with at least one scanning Tele camera disclosed herein; 
         FIG.  4 B  shows schematically in a block diagram another embodiment of a handheld device that includes multi-aperture cameras with at least one scanning Tele camera disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  2 A  shows exemplarily a smartphone  200  comprising a STC  202  at a zero position, and a Wide camera  204 . Wide camera  204  is not a scanning camera and its POV (“POVw”) is parallel to a device normal N (parallel to Z-axis) of the smartphone. Device normal N is parallel (or anti-parallel) to a normal onto a surface of smartphone  200  that has the largest area. A coordinate system of the IMU of smartphone  200  (such as IMU  460  in  FIGS.  4 A and  4 B , not shown here) may be aligned with a coordinate system of smartphone  200  such as the coordinate system shown in  FIG.  2 A , where the three axes of the coordinate system are parallel to the three symmetry axes of smartphone  200 , so that the Z axis of the IMU&#39;s (and smartphone  200 &#39;s) coordinate system is parallel to POV W . The POV of STC  202  (“POV T ”) is directed its zero position (“POV T,0 ”), corresponding to an OPFE rotation state such as shown in  FIG.  1 A . With POV T  at zero position, the coordinate systems of IMU, Wide camera  204  and STC  202  align. 
     In a first exemplary method for OIS (“Example 1”), consider OIS for Wide camera  204  that (for the sake of simplicity) may correct for pitch rotation only. For detecting the amount of undesired hand motion, one could read out the value for pitch rotation around the X axis from the IMU (“X IMU ”) and move e.g. the lens in one particular direction (dir 1 ) by a particular amount, wherein the amount (or stroke) of movement is proportional to X IMU , i.e. the lens stroke S W  fulfills S W =C W .X IMU  (with some constant C W ). The same holds for OIS of STC  202  at zero position. By moving the lens by S T =C T .X IMU  (with some constant C T ) in din the hand motion is compensated. 
       FIG.  2 B  shows smartphone  200  with STC  202  at a non-zero position. POV T  has an angle of α degrees with respect to POV w . For example, for α=30 degrees, this corresponds to an OPFE rotation state such as shown in  FIG.  1 B . The coordinate systems of IMU, Wide camera  204  and STC  202  do not align anymore. 
     Consider Example 1 (hand motion in pitch direction) with STC  202  at a non-zero position. OIS for Wide camera  204  may be performed as in Example 1. However, for OIS of STC  202 , the method of Example 1 does not allow to perform hand motion compensation anymore, i.e. there is (in general) no C T  so that by moving the Tele lens by S T =C T .X IMU , the hand motion is compensated. This is because the coordinate systems of STC  202  and the IMU are not aligned anymore. 
     For a second exemplary method for OIS (“Example 2”), refer to  FIG.  2 C . Compared to  FIG.  2 A , POV T  is rotated by 90 degree around the Y axis, i.e. POV T  and POV W  are perpendicular to each other. As in Example 1, we consider OIS for the Wide camera for correction of pitch rotation only. Hand motion can be fully compensated by reading the IMU&#39;s value for rotation X IMU  and by moving a lens of the Wide camera (not shown) by S W =C W .X IMU  (with some constant C W ) in dir 1 . However, the hand motion cannot be compensated by moving a lens of the STC (not shown, but similar to lens  102 ) by S T =C T .X IMU  (with some constant C T ) in dir 1 . Instead, the rotation direction must be modified from din to a particular direction dir 2  which is different from dir 1 . The hand motion can be compensated by moving the STC lens by S T =C T .X IMU  in dir 2 . In general, for a STC the OIS axes depend on the POV or scanning state of the STC and are thus not constant, as it is the case for a Wide camera. 
       FIG.  3 A  shows a 2-dimensional (2D) chart  320  for deriving a coordinate system for a STC. 
     An aperture  322  of the STC is located at coordinates ( 0 ,  0 ,  0 ). A zero state STC POV T  (POV T,0 )  324  corresponds to a first optical path which is parallel to a device normal N (see  FIG.  2 A-C ) and may have the coordinates ( 0 ,  0 , EFL T ), with EFL T  being the EFL of the STC. FOV T    326  corresponds to the FOV T  of the STC at POV T,0    324 . A desired or target POV T    328  (“POV T,T ”) with corresponding FOV T    332  is shown as well. 
       FIG.  3 B  shows 2D chart  320  of  FIG.  3 A  after the handheld device that includes the STC underwent a rotational “roll” motion around the Z axis, e.g. because of a user&#39;s hand motion. POV T,0    324  did not undergo any change. However, the corresponding FOV T  changed to a rotated FOV T    326 ′. In contrast, the rotational motion changed POV T,T    328  to POV T,T    328 ′. The change of a POV such as POV T,T    328  in response to a rotational device motion depends not only on the angle or amount of rotation, but also on the position of POV T . 
       FIG.  3 C  shows in a flow chart main steps of a method for STC OIS disclosed herein. 
     In a first step  302 , a command triggered by a human user or by a program and processed by a FOV scanner  442  ( FIG.  4 A ) directs FOV T  to a region of interest (ROI) within a scene. The scanning may be performed by rotating an OPFE with an OPFE actuator  414  ( FIG.  4 A ). The FOV scanning by OPFE rotation is not performed instantaneously, but requires some settling time, which may be about 1-50 ms for scanning 2-5 degrees and about 5-500 ms for scanning 10-45 degrees. After the settling time, the STC is operational for capturing Tele images. The STC may be focused to an object by a user command or autonomously. The STC&#39;s scanning direction may be given by an initial (or target) POV vector P I . In step  304 , the IMU is read out and provides rotational movements around the Pitch, Yaw and Roll directions, i.e. X IMU , Y IMU  and Z IMU  respectively. Usually, IMU provides data on the angular acceleration which is to be integrated for determining the rotation angle. The IMU data may be used to calculate the undesired rotational motion of the device. 
     In step  306 , a coordinate transformation is performed. The coordinate transformation is required because the STC&#39;s POV change caused by an undesired rotational motion of the device and the sensing of the undesired rotational motion occur in different coordinate systems. 
     A processing unit such as an AP or a MCU may be configured for performing the coordinate transformation (e.g. AP  440  of device  400  or device  480 , or MCU  470  of device  400  in  FIG.  4 A ). In some examples, an AP or MCU may solve the below equations analytically, or AP or MCU may use a polynomial fit or a linear fit for solving the equations approximately. In other examples, the AP or MCU may not perform calculations but use a Look Up Table (LUT) for coordinate transformation. In some examples and such as e.g. shown in  FIG.  4 A , the coordinate transformation may be performed by a MCU such as MCU  470  connected to the STC module  410 . 
     In some examples, the transformation may be performed in order to express the coordinates of the STC in the coordinate system of the IMU. Device rotations and compensation motions may then be calculated in the IMU&#39;s coordinate system. 
     In some examples, a 2D chart such as chart  320  shown in  FIG.  3 B  may be used to express the coordinates of the STC in the IMU&#39;s coordinate system. Chart  320  may resemble a calibration chart for calibrating the STC or for calibrating a dual-camera, e.g. including a Tele camera and a Wide camera. STC aperture  322  may be located at ( 0 ,  0 ,  0 ). The handheld device may be pointed towards chart  320  in “landscape” direction, i.e. with reference to the coordinate system of  FIG.  3 B , the long side of a smartphone as shown in  FIG.  1 C  may be parallel to the X axis and the short side parallel to the Y axis, with the STC aperture pointing towards the chart in Z direction. All POVs that the STC can reach are given by “POV vectors” or “camera pointing vector” P which are pointing to coordinates lying on chart  320 . The coordinates of the zero state position may be (0, 0, EFL T ) with EFLT being the EFL of the STC. At zero position, the coordinates of the IMU (and of the handheld device) overlap with the STC&#39;s coordinates. 
     If the STC is directed to a non-zero POV, a coordinate transform from the IMU&#39;s to the STC&#39;s coordinates must be performed. In some examples, Rodrigues&#39; rotation formula may be used. The IMU&#39;s pitch/yaw/roll rotation values may be named “hnd_pitch”, “hnd_yaw” and “hnd_roll”. IMU provides hnd_pitch, hnd_yaw and hnd_roll in a coordinate system having the following unit vectors:
         Pitch unit vector R P : R P =(1, 0, 0),   Yaw unit vector R Y : R Y =(0, 1, 0),   Roll unit vector R R : R R =(0, 0, 1).       

     In general, OIS corrects small angles only. Therefore, in some situations and approximately, one may treat the pitch/yaw/roll rotations independently. For any (slight) rotation of the device, Rodrigues&#39; rotation formula may be applied to pitch/yaw/roll rotations independently, wherein the (slight) rotation may be represented by the sum over the pitch/yaw/roll rotations. A hand motion only by hnd_pitch, or only by hnd_yaw or only by hnd_roll (in the IMU&#39;s coordinates R P , R Y  and R R ) applied to any initial POV vector P I  may result in the following final POV vector P F  (“cross(x, y)” indicates the cross product of vectors x and y, “dot(x, y)” indicates the dot product of vectors x and y): 
     POV vector P F   P  after rotation by hnd_pitch around R P  (hnd_yaw, hnd_roll=0): P F   P =(P I ·cos(hnd_pitch)+cross(P I , R P )·sin(hnd_pitch)+R P ·(dot(P I , R P ).(1-cos(hnd_pitch)))); 
     POV vector P F   Y  after rotation by hnd_yaw around R Y  (hnd_pitch, hnd_roll=0): P F   Y =(P I ·cos(hnd_yaw)+cross(P I , R Y )·sin(hnd_yaw)+R Y (dot(P I , R Y ).(1-cos(hnd_yaw)))); 
     POV vector P F   R  after rotation by hnd_roll around R R (hnd_pitch, hnd_yaw=0): P F   R =(P I ·cos(hnd_roll)+cross(P I , R R )·sin(hnd_roll)+R R (dot(P I , R R ).(1-cos(hnd_roll)))). 
     For small angles, a final POV vector (before normalization) P F ′ that underwent both Pitch, Yaw and Roll rotations may be given by: 
       P F ′=P I +(P I -P F   P )+(P I -P F   Y )+(P I -P F   R )
 
     A normalization may be performed in order to ensure that the final POV vector P F  comes to lie on chart  320 . In some examples, P F  may be obtained by normalizing P F ′ with EFL T /P F ′ z , wherein P F ′ z  is the z-component of P F ′, i.e.: 
       P F =P F ′·EFL T /P F ′ z .
 
     From the above equations it is evident that for compensating for undesired rotational hand motion in a STC, in contrast for a non-scanning camera like e.g. Wide camera  204 , where one may compensate the undesired rotational hand motion around yaw and pitch only, one must compensate rotational hand motion around the three directions yaw, pitch and roll. 
     In other examples for coordinate transformation, the transformation may be performed to express the coordinates of the IMU in the coordinate system of the STC. Hand motion rotations and compensation motions may then be calculated in the STC&#39;s coordinate system. As above, Rodrigues&#39; rotation formula may be used. 
     In yet other examples for coordinate transformation, the transformation may be to a third coordinate system (“reference system”). Both the coordinates of the STC and of the IMU are expressed in the reference coordinate system. Hand motion rotations and compensation motions may then be calculated in the reference coordinate system. As above, Rodrigues&#39; rotation formula may be used. 
     In step  308 , movement for OIS may be performed. In some examples, OIS may be performed by moving the STC&#39;s OPFE. In other examples, a lens such as lens  102  and/or an image sensor such as image sensor  106  may be moved for OIS. Assuming ideal OIS, the movement of OPFE and/or lens and/or sensor may lead to a POC vector modification Pois that exactly cancels the effect of the hand motion onto the POV vector, i.e.: P F +P OIS =P I . So after performing step  308  the STC is again directed towards P I . In other examples, the entire STC may be moved for OIS. I.e. OPFE, lens and image sensor are moved together as one unit for OIS. 
     In some embodiments, steps  304 - 308  may be repeated for stabilizing the STC continuously. The OIS cycles that include steps  304 - 308  may be performed at frequencies of e.g. 500 Hz-100 kHz. STC images or image streams are captured while the above OIS method is performed. 
     In some embodiments, an IMU may be fixedly attached to the OPFE, so that when moving the OPFE, the IMU moves accordingly, too. This allows for using coordinate systems having identical basis vectors for both the STC and the IMU, so that the coordinate transform of step  306  is not required. 
     In some embodiments, a sensor actuator may actuate the image sensor for correcting POV aberrations of a STC image. As described in the co-owned international patent application PCT/IB2021/056311, a STC image undergoes POV aberrations. One aberration is a rotation of the STC image on the image sensor (“rotational POV aberration”). When an undesired rotational hand motion is compensated by moving an OPFE as disclosed herein, the moving of the OPFE introduces a POV aberration. A sensor actuator may be used to rotate an image sensor around a normal of the image sensor for compensating the rotational POV aberration. 
       FIG.  4 A  shows schematically an embodiment of a handheld device numbered  400  and including multi-aperture cameras with at least one STC disclosed herein. Device  400  comprises a STC module  410  that includes an OPFE  412  as well as an OPFE actuator  414  for FOV scanning and/or OIS, and a Tele lens module  420  that forms a Tele image recorded by an image sensor  416 . A Tele lens actuator  422  may move lens module  420  for focusing and/or OIS. Handheld device  400  may further comprise an application processor (AP)  440  that includes a FOV scanner  442 , an OIS controller  444 , an image generator  446  and an object tracker  448 . 
     In other examples, device  400  may comprise a STC that includes two OPFEs as well as an OPFE actuator for each of the two OPFEs. In some examples, the OPFE actuators may actuate the OPFEs for performing OIS as disclosed herein. In other examples, a lens actuator may actuate a lens or a sensor actuator may actuate a sensor for performing OIS as disclosed herein. A STC camera based on two OPFEs is described for example in PCT/IB2021/054186. In such a STC, the optical path within the camera is folded twice, so that one speaks of a double-folded scanning Tele camera. 
     Handheld device  400  further comprises a Wide (or Ultra-Wide) camera module  430  which includes a second lens module  434  that forms an image recorded by a second image sensor  432 . A second lens actuator  436  may move lens module  434  for focusing and/or OIS. In some examples, the STC can scan the entire FOV W  or an even larger FOV. In other examples, the STC can scan a FOV that is smaller than FOV W . 
     In some examples, object tracker  448  may be configured to track an object in FOV W  and provide tracking data to FOV scanner  442  and/or the OIS controller  444 . Based on the tracking data, FOV scanner  442  and/or the OIS controller  444  may provide control signals to OPFE actuator  414  which actuate an OPFE rotation for tracking an object with the STC. As an example, one may track an object so that it centers at the center of FOV T . Examples 3-7 described below refer to this tracking scenario, where the Wide camera image data is used to provide tracking information which triggers Tele FOV scanning. 
     In some examples, tracking information and OIS information may interfere and coordination between tracking and OIS may be required for achieving a desired object tracking and/or OIS outcome. 
     As a third exemplary method for OIS, consider a device such as device  400  or  480  including a Wide camera and a STC both not having OIS. The STC may track an object at rest so that the object&#39;s center is located at the center of FOV T . The tracking may occur in real-time (RT), i.e. we assume that there is no delay between the detection of a tracking deviation and its compensation. A device&#39;s rotational motion caused by a user&#39;s hand motion will be detected as an object movement in the Wide camera. In response, a tracking movement of the STC will be triggered and the object&#39;s location in the Tele FOV will be updated. In conclusion, in the RT scenario the object tracker performs OIS in a sense that the object will always be located in the center of FOV T  and will not be affected from hand motion of a user. 
     As a fourth exemplary method for OIS, consider a device such as device  400  or  480  including a Wide camera not having OIS and a STC having OIS. As in example  3 , we assume RT object tracking on FOV W  so that a (non-moving) object&#39;s center is located at the center of FOV T . OIS may be performed in RT as well. A device&#39;s rotational motion caused by a user&#39;s hand motion will be detected as an object movement in the Wide camera. In response, a tracking movement ΔT for the STC will be triggered. Simultaneously, the device&#39;s rotational motion will also be detected by the STC&#39;s OIS and an OIS movement ΔOIS of the STC will be triggered in response. OIS movement may be performed according the OIS method disclosed herein. ΔT and ΔOIS are identical in terms of direction and magnitude, i.e. a STC movement of 2·ΔT=2·ΔOIS will be triggered, which is double the amount of movement required (i) for keeping the object at the center of FOV T  (desired tracking outcome) and (ii) for suppressing the impact of hand motion on the STC image (desired OIS outcome). In conclusion, the desired outcome is not achieved for either Tele tracking or Tele OIS. Therefore, in some examples, the STC&#39;s OIS is disabled when using object tracking. 
     As a fifth exemplary method for OIS, consider a device such as device  400  or  480  including a Wide camera not having OIS and a STC having OIS. Object tracking may be performed on FOV W  so that a (non-moving) object&#39;s center is located at the center of FOV T . However, Object tracking and OIS may not be performed in RT. In general, OIS is performed at higher frequencies than object tracking. As an example, OIS may be performed at 500 Hz-100 kHz and object tracking may be performed at 1 Hz-100 Hz. In some examples, for preventing undesired interference between OIS and object tracking, one may disable OIS when using object tracking. In other embodiments, one may separate control of OIS and object tracking in the frequency domain. As an example, for device&#39;s rotational motion caused by a user&#39;s hand motion that occurs at a frequency higher than e.g. 30 Hz, one may use OIS for device motion correction. For frequencies lower than e.g. 30 Hz one may not use OIS for device motion correction. Instead the low frequency device motion will be compensated by the object tracker. 
     As a sixth exemplary method for OIS, consider a device such as device  400  or  480  including a Wide camera having OIS and a STC not having OIS. Object tracking may be performed on FOV W  so that a (non-moving) object&#39;s center is located at the center of FOV T . Object tracking and OIS may be performed in RT. As of the Wide camera&#39;s OIS, a device&#39;s rotational motion caused by a user&#39;s hand motion will have no impact on the Wide image stream. As the object does not move in FOV W , no tracking movement of the STC will be triggered. In conclusion, there is no hand motion compensation and the object will not be located at the center of FOV T  anymore, leading to an undesired object tracking outcome. In some examples for preventing this undesired outcome, one may disable the Wide camera&#39;s OIS when performing object tracking. In other examples, object tracking control signals that are supplied to the STC may additionally include the Wide camera&#39;s OIS control signals. By superimposing the two signals, the benefits of both Wide camera OIS and proper STC tracking may be enjoyed. 
     As a seventh exemplary method for OIS, consider a device such as device  400  or  480  with both the Wide camera and the STC having OIS. We assume RT tracking so that an object&#39;s center is located at the center of FOV T . A device&#39;s rotational motion caused by a user&#39;s hand motion will be corrected by an OIS movement in both the Wide camera and the STC in RT. In conclusion, a user&#39;s hand motion will not impact the desired output of the object tracker. 
     Calibration data may be stored in a first memory  424 , e.g. in an EEPROM (electrically erasable programmable read only memory) and/or in a second memory  438  and/or in a third memory  450  such as a NVM (non-volatile memory). The calibration data may comprise calibration data between Wide camera  430  and STC  410 . The calibration data may further comprise calibration data between an OPFE&#39;s position and the STC&#39;s corresponding POV. 
     Handheld device  400  further comprises an inertial measurement unit (IMU, for example a gyroscope)  460  that supplies motion information of  400 . For example, a microcontroller unit (MCU)  470  may be used to read and process data of IMU  460 . In some examples, the MCU may be controlled by an OIS controller  444  which is part of AP  440 . In some examples, step  304  and step  306  may be performed by the MCU and step  308  may be performed by OPFE actuator  414  (and/or lens actuator  436  and/or sensor actuator  418  in case OIS is performed by lens shift or sensor shift respectively). In some examples, MCU  470  may be integrated into AP  440 . 
     Another embodiment of a handheld device numbered  480  and comprising a multi-aperture camera with at least one STC as disclosed herein is shown in  FIG.  4 B . An MCU (not shown) for reading and processing motion data from IMU  460  and for supplying OIS control signals may be included into STC module  410 , e.g. into the driver of OPFE actuator  414 . 
     In some examples, additional data may be used for hand motion estimation. Additional data may e.g. be image data from the Wide camera  430  or data from additional sensing units present in the handheld device. 
     In some examples, image data from Wide camera  430  may be used to estimate an “optical flow” from a plurality of images as known in the art, wherein OIS controller  444  may use the data of the optical flow together with data from IMU  460  for estimating motion of device  400 . In other examples, only optical flow data estimated from image data of camera  410  and/or camera  430  may be used for estimating motion of device  400 . 
     Image generator  446  may be configured to generate images and image streams. In some examples, image generator  446  may be configured to use only first image data from camera  430 . In other examples, image generator  446  may use image data from camera  410  and/or camera  430 . 
     While this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of the embodiments and methods will be apparent to those skilled in the art. The disclosure is to be understood as not limited by the specific embodiments described herein, but only by the scope of the appended claims. 
     Unless otherwise stated, the use of the expression “and/or” between the last two members of a list of options for selection indicates that a selection of one or more of the listed options is appropriate and may be made. 
     It should be understood that where the claims or specification refer to “a” or “an” element, such reference is not to be construed as there being only one of that element. 
     Furthermore, for the sake of clarity the term “substantially” is used herein to imply the possibility of variations in values within an acceptable range. According to one example, the term “substantially” used herein should be interpreted to imply possible variation of up to 5% over or under any specified value. According to another example, the term “substantially” used herein should be interpreted to imply possible variation of up to  2 . 5 % over or under any specified value. 
     According to a further example, the term “substantially” used herein should be interpreted to imply possible variation of up to  1 % over or under any specified value. 
     All patents and/or patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual reference was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.