Patent Publication Number: US-2023133339-A1

Title: Actuator to blur dark bands in illumination

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 63/275,248, filed on Nov. 3, 2021, the entirety of which is hereby incorporated by reference herein. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to an illumination system, such as for a camera. 
     BACKGROUND OF THE DISCLOSURE 
     There is ongoing effort to improve illumination systems, such as for cameras. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a side view of an example of an illumination system for a camera, in accordance with some examples. 
         FIG.  2    shows a front view of an example of an LED array that can include one or more non-emitting areas located between adjacent LEDs in the LED array, in accordance with some examples. 
         FIG.  3    shows a front view of an example of illumination that can include one or more dark bands corresponding to the one or more non-emitting areas of the LED array, in accordance with some examples. 
         FIG.  4    shows a flowchart of an example of a method for illuminating a scene, in accordance with some examples. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Elements in the drawings are not necessarily drawn to scale. The configurations shown in the drawings are merely examples and should not be construed as limiting in any manner. 
     DETAILED DESCRIPTION 
     An illumination system for a camera can illuminate a scene with a light-emitting diode (LED) array and a collimating lens. The illumination system can have a problem of dark bands (e.g., non-emitting areas) of the LED array producing one or more dark bands in the illumination of the illuminated scene. To overcome the problem, the illumination system can use an actuator to translate at least one of the LED array or the collimating lens during an exposure duration of the camera, so as to blur the one or more dark bands in the illumination in the image of the scene. 
       FIG.  1    shows a side view of an example of an illumination system  100  for a camera  102 , in accordance with some examples. The camera  102  can capture an image of a scene  104  during an exposure duration of the camera  102 . In  FIG.  1   , the scene  104  is shown as being a happy cat; other suitable scenes can also be used. 
     The illumination system  100  can include a light-emitting diode (LED) array  106 . The LED array  106  can include a plurality of LEDs  108  that can produce light  110  during the exposure duration of the camera  102 . The LED array  106  can include one or more non-emitting areas  212  (shown in  FIG.  2   ) located between adjacent LEDs  108  in the LED array  106 . In some examples, one or more of the non-emitting areas  212  can surround the LEDs  108  in the LED array  106 . 
       FIG.  2    shows a front view of an example of an LED array  106  that can include one or more non-emitting areas  212  located between adjacent LEDs  108  in the LED array  106 , in accordance with some examples. In some examples, the LED array  106  can include a monolithic LED that is segmented, where each segment (or subset of segments) can be individually addressed and powered. For the purposes of this document, such individually addressable segments are considered to be individual LEDs  108 . In some examples, the LED array  106  can include LEDs  108  arranged in a 3-by-3 pattern. In some examples, the LED array  106  can include LEDs  108  arranged in a 4-by-5 pattern. In some examples, the LED array  106  can include LEDs  108  arranged in a 7-by-7 pattern. 
     Returning to  FIG.  1   , the illumination system  100  can include a lens  114 . The lens  114  can direct the light  110  toward the scene  104  as illumination  116 . The illumination  116  can include one or more dark bands  318  (shown in  FIG.  3   ) corresponding to the one or more non-emitting areas  212  of the LED array  106 . 
       FIG.  3    shows a front view of an example of illumination  116  that can include one or more dark bands  318  corresponding to the one or more non-emitting areas  212  of the LED array  106 , in accordance with some examples. 
     Returning to  FIG.  1   , the illumination system  100  can include an actuator  120 . The actuator  120  can translate at least one of the LED array  106  or the lens  114  during the exposure duration of the camera  102  so as to blur the dark bands  318  in the illumination  116  in the image of the scene  104 . In some examples, the actuator  120 A can translate the LED array  106  with respect to the lens  114 . In some examples, the actuator  120 B can translate the lens  114  with respect to the LED array  106 . In some examples, the actuator  120  can translate both the lens and the LED array. For the purposes of this document, the actuator  120  can include a single element that can produce translation, such as  120 A or  120 B, or both elements  120 A and  120 B that can produce translation. The actuator  120  can include a single element for both the LED array  106  and the lens  114 , or can alternatively include separate elements for the LED array  106  and the lens  114 . 
     In some examples, the lens  114  can define a longitudinal axis that extends from the LED array  106 , through a center of the lens  114 , to the scene  104 . 
     In some examples, the actuator  120  can be a one-dimensional actuator that can translate at least one of the LED array  106  or the lens  114  in an actuation direction that is angled with respect to the longitudinal axis. In some examples, the actuation direction can be generally orthogonal to the longitudinal axis. In some examples, the LED array  106  can be arranged in a two-dimensional pattern having a first array direction and a second array direction that is orthogonal to the first array direction. In some examples, the actuation direction can be angled with respect to the first array direction and angled with respect to the second array direction. In some examples, the LED array  106  can be arranged in a one-dimensional pattern that extends along an array direction. In some examples, the actuation direction can be non-orthogonal to the array direction. In some examples, the actuation direction can be generally parallel to the array direction. In some examples, the actuator  120  can translate at least one of the LED array  106  or the lens  114  in the actuation direction by a (peak-to-valley) distance greater than or equal to a width of a non-emitting area of the one or more non-emitting areas  212  of the LED array  106  during the exposure duration of the camera  102 . The width can be a projected width along the actuation direction, which can be greater than the width along the orthogonal axes of the LED array  106 . In some examples, the actuator  120  can oscillate at least one of the LED array  106  or the lens  114  in the actuation direction. In some examples, the oscillation can have an oscillation period that is less than the exposure duration of the camera, such as one-half of the exposure duration, one-fifth of the exposure duration, one-tenth of the exposure duration, or other suitable values. 
     In some examples, the actuator  120  can be a two-dimensional actuator that can translate at least one of the LED array  106  or the lens in an actuation plane that is angled with respect to the longitudinal axis. For example, the actuator  120  can include two movement-producing elements, with one element coupled to the LED array  106  and the other movement-producing element coupled to the lens  114 . In some examples, the actuation plane can be generally orthogonal to the longitudinal axis. 
     In some examples, movement of the actuator  120  can vary as a function of which LEDs  108  in the LED array  106  are powered. For example, for a duration in which only a single row of LEDs  108  is powered, the actuator  120  can move in a direction that is parallel to the row. Similarly, for another duration in which only a single column of LEDs  108  is powered, the actuator  120  can move in a direction that is parallel to the column. In some examples, the actuator  120  can move in a rotational pattern, such as an oscillating pattern in a plane that can be generally orthogonal to the longitudinal axis. In some examples, the oscillating pattern can include a Lissajous pattern. In some examples, the actuator can include actuating elements that are orthogonal or substantially orthogonal. The actuating elements can approximate any suitable oscillating pattern using stair step operation. In some examples, the actuator  120  can include a translating element (e.g., an element that directly produces translation). In some examples, the actuator  120  can include a rotating element (e.g., an element that directly produces rotation, rather than translation). In some examples, the actuator  120  can produce movement that is entirely or partially along the longitudinal axis. The movement (or component of the movement) along the longitudinal axis can produce defocus, which can blur the dark bands in the illumination pattern. 
     The camera  102  can include a camera lens  122  that can collect reflected light  124  that is reflected from and/or emitted by the scene  104 . The camera lens  122  can direct the reflect light  124  onto a multi-pixel sensor  126  to form an image of the scene  104  on the multi-pixel sensor  126 . A controller  128  can receive a data signal that represents the image of the scene  104 . The controller  128  can optionally additionally drive the actuator  120 . In some examples, the controller  128  can cause the actuator  120  to move in a specified manner. For example, the controller  128  can receive a request to illuminate the scene  104  with a single segment of the LED array  106 , or a single row or column of the LED array  106 . The controller  128  can, in response to the request to illuminate the scene  104  in a particular manner, cause the actuator  120  to move in a specified manner. For example, the controller  128  can cause the actuator  120  to move in one dimension, an orthogonal dimension, or in one or more two-dimensional patterns. The controller  128  can optionally additionally drive the LEDs  108  in the LED array  106 . For example, the controller can optionally control one or more LEDs  108  in the LED array  106  independent of another one or more LEDs  108  in the LED array  106 , so as to illuminate the scene in a specified manner. For example, relatively close objects in the scene  104  may require a first amount of illumination, and relatively distant objects in the scene  104  may require a second amount of illumination, greater than the first amount, to have a same brightness in the image of the scene  104 . Other configurations are also possible. The camera  102  and illumination system  100  can be disposed in a housing  130 . In some examples, the housing  130  can be configured as a smart phone or other suitable device. 
       FIG.  4    shows a flowchart of an example of a method  400  for illuminating a scene, in accordance with some examples. The method  400  can be executed by the illumination system  100 , or by another suitable illumination system. The method  400  is but one method for illuminating a scene. Other suitable methods can also be used. 
     At operation  402 , a camera, such as camera  102 , can capture an image of the scene, such as scene  104 , during an exposure duration of the camera. 
     At operation  404 , an LED array, such as LED array  106 , can produce light, such as light  110 , during the exposure duration of the camera. The LED array can include a plurality of LEDs, such as LEDs  108 , configured to produce the light. The LED array can include one or more non-emitting areas, such as non-emitting areas  212 , located between adjacent LEDs in the LED array. 
     At operation  406 , a lens, such as lens  114 , can direct the light toward the scene as illumination, such as illumination  116 . The illumination can include one or more dark bands, such as dark bands  318 , corresponding to the one or more non-emitting areas of the LED array. 
     At operation  408 , an actuator, such as actuator  120 , can translate at least one of the LED array or the lens during the exposure duration of the camera so as to blur the dark bands in the illumination in the image of the scene. 
     In some examples, the lens can define a longitudinal axis that extends from the LED array, through a center of the lens, to the scene. In some examples, the actuator can be a one-dimensional actuator that translates at least one of the LED array or the lens in an actuation direction that is angled with respect to the longitudinal axis. In some examples, the actuator can be a two-dimensional actuator that translates at least one of the LED array or the lens in an actuation plane that is generally orthogonal to the longitudinal axis. 
     In some examples, the actuator can translate at least one of the LED array or the lens in the actuation direction by a distance greater than or equal to a width of the non-emitting area of the LED array during the exposure duration of the camera. 
     In some examples, the actuator can oscillate at least one of the LED array or the lens in the actuation direction. The oscillation can have an oscillation period that is less than the exposure duration of the camera. 
     In some examples, the lens can define a longitudinal axis that extends from the LED array, through a center of the lens, to the scene. 
     To further illustrate the systems and related methods disclosed herein, a non-limiting list of examples is provided below. Each of the following non-limiting examples can stand on its own or can be combined in any permutation or combination with any one or more of the other examples. 
     In Example 1, an illumination system for a camera, the camera configured to capture an image of a scene during an exposure duration of the camera, can include: a light-emitting diode (LED) array including a plurality of LEDs configured to produce light during the exposure duration of the camera, the LED array including a non-emitting area located between adjacent LEDs in the LED array; a lens configured to direct the light toward the scene as illumination, the illumination including a dark band corresponding to the non-emitting area of the LED array; and an actuator configured to translate at least one of the LED array or the lens during the exposure duration of the camera to blur the dark band in the illumination in the image of the scene, the dark band blurred in response to translation of the at least one of the LED array or the lens. 
     In Example 2, the illumination system of Example 1 can optionally be configured such that the actuator is configured to translate the LED array, the LED array translated with respect to the lens. 
     In Example 3, the illumination system of any one of Examples 1-2 can optionally be configured such that the actuator is configured to translate the lens, the lens translated with respect to the LED array. 
     In Example 4, the illumination system of any one of Examples 1-3 can optionally be configured such that the actuator is configured to translate both the lens and the LED array. 
     In Example 5, the illumination system of any one of Examples 1-4 can optionally be configured such that: the lens defines a longitudinal axis that extends from the LED array, through a center of the lens, to the scene; and the actuator is a one-dimensional actuator that is configured to translate at least one of the LED array or the lens in an actuation direction that is angled with respect to the longitudinal axis. 
     In Example 6, the illumination system of any one of Examples 1-5 can optionally be configured such that the actuation direction is generally orthogonal to the longitudinal axis. 
     In Example 7, the illumination system of any one of Examples 1-6 can optionally be configured such that: the LED array is arranged in a two-dimensional pattern having a first array direction and a second array direction that is orthogonal to the first array direction; and the actuation direction is angled with respect to the first array direction and angled with respect to the second array direction. 
     In Example 8, the illumination system of any one of Examples 1-7 can optionally be configured such that: the LED array is arranged in a one-dimensional pattern that extends along an array direction; and the actuation direction is non-orthogonal to the array direction. 
     In Example 9, the illumination system of any one of Examples 1-8 can optionally be configured such that the actuation direction is generally parallel to the array direction. 
     In Example 10, the illumination system of any one of Examples 1-9 can optionally be configured such that the actuator is configured to translate at least one of the LED array or the lens in the actuation direction by a distance greater than or equal to a width of the non-emitting area of the LED array during the exposure duration of the camera. 
     In Example 11, the illumination system of any one of Examples 1-10 can optionally be configured such that the actuator is configured to oscillate at least one of the LED array or the lens in the actuation direction. 
     In Example 12, the illumination system of any one of Examples 1-11 can optionally be configured such that the oscillation has an oscillation period that is less than the exposure duration of the camera. 
     In Example 13, the illumination system of any one of Examples 1-12 can optionally be configured such that: the lens defines a longitudinal axis that extends from the LED array, through a center of the lens, to the scene; and the actuator is a two-dimensional actuator that is configured to translate at least one of the LED array or the lens in an actuation plane that is angled with respect to the longitudinal axis. 
     In Example 14, the illumination system of any one of Examples 1-13 can optionally be configured such that the actuation plane is generally orthogonal to the longitudinal axis. 
     In Example 15, a method for illuminating a scene can include: capturing, with a camera, an image of the scene during an exposure duration of the camera; producing, with a light-emitting diode (LED) array, light during the exposure duration of the camera, the LED array including a plurality of LEDs configured to produce the light, the LED array including a non-emitting area located between adjacent LEDs in the LED array; directing, with a lens, the light toward the scene as illumination, the illumination including a dark band corresponding to the non-emitting area of the LED array; and translating, with an actuator, at least one of the LED array or the lens during the exposure duration of the camera to blur the dark band in the illumination in the image of the scene, the dark band blurred in response to translation of the at least one of the LED array or the lens. 
     In Example 16, the method of Example 15 can optionally be configured such that: the lens defines a longitudinal axis that extends from the LED array, through a center of the lens, to the scene; and the actuator is a one-dimensional actuator that translates at least one of the LED array or the lens in an actuation direction that is angled with respect to the longitudinal axis. 
     In Example 17, the method of any one of Examples 15-16 can optionally be configured such that the actuator translates at least one of the LED array or the lens in the actuation direction by a distance greater than or equal to a width of the non-emitting area of the LED array during the exposure duration of the camera. 
     In Example 18, the method of any one of Examples 15-17 can optionally be configured such that the actuator oscillates at least one of the LED array or the lens in the actuation direction, the oscillation having an oscillation period that is less than the exposure duration of the camera. 
     In Example 19, the method of any one of Examples 15-18 can optionally be configured such that: the lens defines a longitudinal axis that extends from the LED array, through a center of the lens, to the scene; and the actuator is a two-dimensional actuator that translates at least one of the LED array or the lens in an actuation plane that is generally orthogonal to the longitudinal axis. 
     In Example 20, an illumination system can include: a camera configured to capture an image of a scene during an exposure duration of the camera; a light-emitting diode (LED) array including a plurality of LEDs configured to produce light during the exposure duration of the camera, the LED array including a non-emitting area surrounding the LEDs in the LED array; a lens configured to direct the light toward the scene as illumination, the illumination including one or more dark bands corresponding to the non-emitting area of the LED array; and an actuator configured to translate at least one of the LED array or the lens during the exposure duration of the camera so as to blur the one or more dark bands in the illumination in the image of the scene, the one or more dark bands blurred in response to translation of the at least one of the LED array or the lens. 
     In Example 21, an illumination system can include: at least one processor; and non-transitory memory including non-transitory instructions that, when executed by the processor, cause the processor to perform operations, the operations including: capturing, with a camera, an image of the scene during an exposure duration of the camera; producing, with a light-emitting diode (LED) array, light during the exposure duration of the camera, the LED array including a plurality of LEDs configured to produce the light, the LED array including a non-emitting area located between adjacent LEDs in the LED array; directing, with a lens, the light toward the scene as illumination, the illumination including a dark band corresponding to the non-emitting area of the LED array; and translating, with an actuator, at least one of the LED array or the lens during the exposure duration of the camera to blur the dark band in the illumination in the image of the scene, the dark band blurred in response to translation of the at least one of the LED array or the lens. 
     In Example 22, the illumination system of Example 21 can optionally be configured to include the limitations of any one of Examples 1-20. 
     While only certain features of the system and method have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes. Method operations can be performed substantially simultaneously or in a different order.