Device for Determining an Optical Characteristic of a Camera

Abstract

The techniques of this disclosure relate to determining an optical characteristic of a camera. The device includes a housing that receives a test fixture retaining a camera. The housing includes a first segment and a second segment creating a chamber surrounding the camera. The first segment is attached to the test fixture and defines a first orifice located in a side of the first segment. The first orifice directs a flow of a gas out of the chamber. The second segment defines a second orifice located in a first side of the second segment to direct the flow of the gas into the chamber. An aperture is located in a second side of the second segment and positioned opposite the test fixture to define a field of view that includes a camera target. The aperture receives a lens barrel of the camera and enables the determination of the optical characteristic.

What is claimed is: 
     
         1 . A device comprising:
 a housing configured to define a chamber to receive a test fixture that retains a camera for determining an optical characteristic of the camera, the housing:
 being configured to attach to the test fixture; 
 defining a first orifice located in a first side of the housing, the first orifice being configured to direct a flow of a gas into or out of the chamber; 
 defining a second orifice located in a second side of the housing to direct the flow of the gas out or into the chamber; and 
 defining an aperture located in a third side of the housing and configured to accommodate a field of view of the camera to enable a determination of the optical characteristic. 
   
     
     
         2 . The device of  claim 1 , wherein the chamber comprises an environmental chamber and the device is configured to be placed on or integrated into a test stand. 
     
     
         3 . The device of  claim 2 , wherein the aperture is configured to provide the camera with a view through the aperture to a collimator on the test stand. 
     
     
         4 . The device of  claim 2 , wherein a fitting is attached to the housing to direct the flow of the gas through the first orifice or the second orifice through a first end, the fitting being configured so that a second end is positioned toward a floor of the test stand. 
     
     
         5 . The device of  claim 1 , wherein the aperture is sized, shaped, or arranged relative to the test fixture to receive a lens barrel of the camera and enable a determination of the optical characteristic. 
     
     
         6 . The device of  claim 5 , wherein the aperture is further defined by a conical section that protrudes into the chamber toward the test fixture, the conical section defining an annulus between the lens barrel and a leading edge of the conical section. 
     
     
         7 . The device of  claim 6 , wherein the conical section is formed integral to the housing or attached as a separate component to the housing. 
     
     
         8 . The device of  claim 6 , wherein a diameter of the annulus is configured to not occlude the field of view of the camera during measurement of the optical characteristic. 
     
     
         9 . The device of  claim 1 , wherein the housing comprises a first segment and a second segment attached to the first segment to define the chamber. 
     
     
         10 . The device of  claim 9 , wherein the second segment is removably attached to the first segment using fasteners. 
     
     
         11 . The device of  claim 1 , wherein the optical characteristic includes an optical transfer function (OTF) or modulation transfer function (MTF). 
     
     
         12 . The device of  claim 1 , wherein the housing is further configured to align an optical axis of the camera with a rotational axis of the test fixture during installation of the camera. 
     
     
         13 . The device of  claim 1 , wherein the housing or a portion of the housing is configured to attach to the test fixture to minimize a relative movement between the test fixture and the housing or the portion of the housing. 
     
     
         14 . The device of  claim 13 , wherein the housing or the portion of the housing is configured to attach to the test fixture using threaded fasteners inserted through holes in a floor of the housing or the portion of the housing that interface with corresponding threaded holes in the test fixture. 
     
     
         15 . The device of  claim 1 , wherein:
 the first orifice is positioned proximate to a floor of the housing;   the second orifice is positioned proximate to a ceiling of the housing; and   the aperture is positioned in the ceiling of the housing.   
     
     
         16 . The device of  claim 1 , wherein the first orifice and the second orifice are positioned at different elevations of the housing relative to the test fixture. 
     
     
         17 . The device of  claim 1 , wherein the first orifice and the second orifice are positioned to enable an inlet flow direction of the gas into the chamber be normal to an outlet flow direction of the gas out of the chamber. 
     
     
         18 . The device of  claim 1 , wherein areas of the first orifice and the second orifice are sized to maintain a particular backpressure of the chamber. 
     
     
         19 . The device of  claim 1 , wherein the housing is further configured to accommodate a cap or plug to seal the aperture to minimize thermal losses from the chamber while the camera is being held at a test temperature set point. 
     
     
         20 . The device of  claim 1 , wherein the housing is formed of a polymer material.