An automatic focusing camera which includes an image sensor is provided having a fixed lens system with a lens having an object side and an image side. The fixed lens system is located in a fixed position relative to the image sensor. A mirror is moveably positioned between the image side of at least one lens and the image sensor. The mirror is located at an angle such that an image observed through the fixed lens system is reflected toward the image sensor. An actuator is connected to the mirror and moves the mirror relative to the lens system to change a distance between the lens system and the image sensor to adjust an object focal length between an object and the object side of the lens.
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7. Method for automatic focusing of a camera having an image sensor and a lens system with a lens located at a fixed position relative to the image sensor, comprising:
providing a mirror movably mounted between an image side of the lens system and the image sensor; and
adjusting the position of the mirror to vary a length of an optical path between the imaging sensor and the lens system to vary an object focal point on an object being observed.
0. 10. An automatic focusing camera, comprising:
an image sensor;
a lens having an object side and an image side;
a mirror movably positioned between the image side of the lens and the image sensor, the mirror being located at an angle such that an image observed through the lens is reflected toward the image sensor; and
wherein the mirror is pivotably movable about a pivot point, the pivot point being located on an opposite side of the image sensor from the mirror, and pivotable motion of the mirror changes a distance between the lens and the image sensor to adjust an object focal length between an object and the camera.
1. automatic focusing camera comprising:
an image sensor;
a fixed lens system having a lens with an object side and an image side, the fixed lens system being located in a fixed position relative to the image sensor;
a mirror movably positioned between the image side of the lens and the image sensor, the mirror being located at an angle such that an image observed through the fixed lens system is reflected toward the image sensor; and
an actuator connected to the mirror that moves the mirror relative to the lens system to change a distance between the lens system and the image sensor to adjust an object focal length between an object and the camera.
0. 19. An automatic focusing camera, comprising:
an image sensor;
a lens with an object side and an image side;
a mirror positioned between the image side of the lens and the image sensor such that an image observed through the lens is reflected toward the image sensor; and
a non-articulated arm including a pivot point fixed relative to the lens, the mirror being fixed to the arm such that the arm extends outwardly beyond the mirror toward the image sensor, the arm being pivotably movable about the pivot point;
wherein movement of the mirror relative to the lens changes a distance between the lens and the image sensor to adjust an object focal length between an object and the camera.
2. The automatic focusing camera of
3. The automatic focusing camera of
5. The automatic focusing camera of
8. Method for automatic focusing of
moving the mirror linearly along a path parallel to an optical axis of the lens system to adjust the position of the mirror.
9. Method for automatic focusing of
moving the mirror about a pivot point located along an optical axis of the image sensor; and
receiving an image to be scanned as a single line in a plane of the image sensor.
0. 11. The automatic focusing camera of claim 10, wherein the lens is fixed relative to the image sensor.
0. 12. The automatic focusing camera of claim 10, wherein the lens is an objective lens.
0. 13. The automatic focusing camera of claim 10, wherein the lens further comprises a single lens.
0. 14. The automatic focusing camera of claim 10, wherein the pivot point is located along an optical axis of the image sensor.
0. 15. The automatic focusing camera of claim 10, further comprising an actuator connected to the mirror that moves the mirror relative to the lens to change a distance between the lens and the image sensor.
0. 16. The automatic focusing camera of claim 15, the actuator further comprising one of a voice coil, a solenoid, and a stepper motor.
0. 17. The automatic focusing camera of claim 10, further comprising an arm on which the mirror is mounted, the arm being connected to the pivot point.
0. 18. The automatic focusing camera of claim 17, wherein the pivot point further comprises a leaf spring.
0. 20. The automatic focusing camera of claim 19, wherein the image sensor is fixed relative to the lens.
0. 21. The automatic focusing camera of claim 19, wherein the pivot point is on an opposite side of the image sensor from the mirror.
0. 22. The automatic focusing camera of claim 19, wherein the pivot point is located on an optical axis of the image sensor.
0. 23. The automatic focusing camera of claim 19, further comprising an actuator connected to the arm that pivotably moves the mirror about the pivot point.
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The present invention is directed to an automatic focusing camera, and more particularly to an automatic focusing line scan camera for use in scanning applications.
In scanning applications, for examples for packages traveling along a conveyor, it is often required that scans be carried out at varying target distances. For example, if a larger package moves along a conveyor beneath a scanner, the distance between the lens of the scanning camera system and the object is shorter than for a smaller package traveling along the same conveyor path. Prior known systems generally provide focusing for the scanning camera by adjusting the position of the lens system or the image sensor to focus the image plane on the senor. However, this can result in higher costs for systems employing movement of one or more lens in order to maintain the optical alignment of the lens relative to one another and the sensor. Additionally, movement of the image sensor can add additional complexity and cost due to the need to provide electrical connections to an from the imaging sensor and to maintain the desired orientation of the sensor over the path of movement.
It would be desirable to be able to provide adjustment of the object focal length without the need for moving either the lens system (or one or more lenses therein) or the sensor relative to one another in order to provide a simple and reliable automatic focusing system for a camera system, preferably for use in scanning applications.
Briefly stated, the present invention is an automatic focusing camera which includes an image sensor. A fixed lens system is provided having a lens with an object side and an image side. The fixed lens system is located in a fixed position relative to the image sensor. A mirror is moveably positioned between the image side of the lens system and the image sensor. The mirror is located at an angle such that an image observed through the fixed lens system is reflected toward the image sensor. An actuator is connected to the mirror and moves the mirror relative to the lens system to change a distance between the lens system and the image sensor to adjust an object focal length between an object and the camera.
In another aspect, the present invention provides a method for automatic focusing of a camera having an image sensor and a lens system with an objective lens located at a fixed position relative to the image sensor. The method comprises: (a) providing a mirror moveably mounted between an image side of the lens system and the image sensor; and (b) adjusting the position of the mirror to vary a length of an optical path between the image sensor and the lens system to vary an object focal point on an object being observed.
The foregoing summary, as well as the following detailed description of the preferred embodiments of the invention will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention/is not limited to precise arrangements shown. In the drawings:
Certain terminology is used in the following description for convenience only and is not considered limiting. The words “right”, “left”, “lower”, and “upper” designate directions in the drawings to which reference is made. The terminology includes the words specifically noted above, derivatives thereof and words of similar import. Additionally, the terms “a” and “one” are defined as including one or more of a referenced item unless specifically noted.
Referring to the drawings, wherein like numerals designate like elements throughout, there is shown in
Still with reference to
An actuator 24 is connected to the mirror 20 that moves the mirror 20 relative to the lens system 14 to change a distance between the lens system 14 and the image sensor 12 to adjust an object focal length between an object (not shown in
In a preferred embodiment, the actuator 24 is a voice coil. However, those skilled in the art will understand from the present disclosure that the actuator 24 may be constructed as a solenoid or a stepper motor with a lead screw or using any other suitable controllable displacement means. In the first preferred embodiment, the pivot point 30 is formed by a pin connection. However, it will be recognized by those skilled in the an from the present disclosure that the pivot could be provided by a flexible member such as a leaf spring or a living hinge which would provide the additional advantage of biasing the arm 28 in a given direction to maintain greater stability of the mirror 20, if desired.
As shown in
In the preferred embodiment, the focusing mechanism is used in conjunction with a line-scan camera system, such as a line-scan CCD camera as the image sensor 12. This is due to the fact that if the object plane and the nodal plane of the lens system 14 are parallel, then the image plane at the image sensor 12 must also be parallel to both the object and nodal planes in order for a complete image to be in focus. The pivoting of the mirror 20 in the first preferred embodiment causes the sensor plane to be non-parallel to the lens nodal plane resulting in an out-of-focus condition for all except a single line in the sensor plane across the face of the image sensor 12. However, as long the image sensor 12 is a single-line sensor located at this line of perfect focus, then the image sensor 12 will see the object without distortion. This is especially useful for scanning applications where a single scan line is generally being observed aid imaged by the camera 10.
Referring now to
In the second preferred embodiment of the invention, the automatic focusing camera 110 includes a mirror 120 which is mounted for generally linear movement parallel to the optical axis 22 of the lens system 14. Preferably, the mirror 120 is connected to a linear actuator 124 for movement of the mirror 120 from a first position to a second position 120′, as shown by dashed lines in
While in the second preferred embodiment a line-scan camera is also used as the image sensor 12, it is also possible to utilize a two dimensional image sensor 12 in connection with the second preferred embodiment since the object, lens and sensor planes all remain parallel to the field of view of the image sensor 12.
In use, the position of the mirrors 20, 120 of the automatic focusing cameras 10, 110 are adjusted to vary a length of an optical path between the imaging sensor 12 and the lens system 14 to vary an object focal point on an object being observed. In the first preferred embodiment, this is accomplished by moving the mirror about the pivot point 30, shown in
While the preferred embodiments of the invention have been described in detail, the invention is not limited to the specific embodiments described above which should be considered as merely exemplary. Further modifications and extensions of the present invention may be developed, and all such modifications are deemed to be within the scope and spirit of the present invention as defined by the appended claims and all legal equivalents thereto.
Veksland, Michael L., Skokowski, Jr., Richard J.
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Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Oct 04 2006 | Accu-Sort Systems, Inc. | (assignment on the face of the patent) | / | |||
Feb 21 2007 | SKOKOWSKI JR , RICHARD J | ACCU-SORT SYSTEMS, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 019048 | /0371 | |
Feb 27 2007 | VEKSLAND, MICHAEL L | ACCU-SORT SYSTEMS, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 019048 | /0371 | |
Jul 01 2012 | ACCU-SORT SYSTEMS, INC | DATALOGIC AUTOMATION, INC | MERGER SEE DOCUMENT FOR DETAILS | 032407 | /0103 | |
Dec 13 2016 | DATALOGIC ADC, INC | DATALOGIC USA, INC | MERGER SEE DOCUMENT FOR DETAILS | 067878 | /0571 | |
Dec 13 2016 | DATALOGIC AUTOMATION, INC | DATALOGIC USA, INC | MERGER SEE DOCUMENT FOR DETAILS | 067878 | /0571 |
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