Dynamics of an image viewed through a rotating mirror

Non-Rotationally Symmetric Field Mapping for Back-Scanned Step/Stare Imaging System

“…Further, the FSM placed behind the afocal telescope could be considered to have nothing to do with the image quality by optical designers. Actually, the movement required to track an image viewed through a rotating mirror is a nonlinear function of the mirror movement, but this fact is always neglected [20]. The optimization commands of Zemax software are utilized to set the relationship among the image height, the focal length and the incident angle of the imaging system to meet Equation (2).…”

“…Further, the FSM placed behind the afocal telescope could be considered to have nothing to do with the image quality by optical designers. Actually, the movement required to track an image viewed through a rotating mirror is a nonlinear function of the mirror movement, but this fact is always neglected [20]. Figure 8.…”

“…However, it is frequently assumed that the virtual of a target viewed through a rotating mirror moves with respect to the observer at twice the angular rate of mirror rotation, which is inaccurate and leads to imprecise treatment of open-loop tracking systems. The reason is that the sample of rays reflected from a target to an arbitrary tracker position changes as a function of mirror orientation, and the angle of incidence is not a linear function of mirror orientation, but depends on the relative positions of the target, mirror, and tracker, as well as the orientation of the mirror [20,21].Although the equations describing the line-of-sight kinematics derive entirely from the simple plane mirror law of reflection, they are non-linearly-and axis-coupled and these effects increase as the FSM angular displacement increases, which would contribute to pointing errors in certain modes of operation [9].…”

“…With small size, high accuracy, high bandwidth and fast response speed, FSMs are widely applied in electro-optical and infrared sensors [17][18][19].However, it is frequently assumed that the virtual of a target viewed through a rotating mirror moves with respect to the observer at twice the angular rate of mirror rotation, which is inaccurate and leads to imprecise treatment of open-loop tracking systems. The reason is that the sample of rays reflected from a target to an arbitrary tracker position changes as a function of mirror orientation, and the angle of incidence is not a linear function of mirror orientation, but depends on the relative positions of the target, mirror, and tracker, as well as the orientation of the mirror [20,21].Although the equations describing the line-of-sight kinematics derive entirely from the simple plane mirror law of reflection, they are non-linearly-and axis-coupled and these effects increase as the FSM angular displacement increases, which would contribute to pointing errors in certain modes of operation [9].As discussed above, the back-scanned step/stare imaging system can scan a large field of regard at a high rate and with diffraction limited performance. However, the traditional optical design forms can hold only one field point relatively stable on the FPA, typically the central or on-axis field point; all other off-axis field points may wander during the exposure time due to image distortion characteristics of the imaging systems, which reduces the SNR of the target.…”

Stimulus Determinants of Dynamic Visual Acuity. III. Effects of Proximal Borders and Limited Surround,

“…The plane of incdence was perpendicular to the axis of mirror rotation. With this geometry, the mean angular speed of the target image with respect to the eye is 1.94 times the speed of mirror rotation (27). An up-and-down psychophysical method was employed in which the target size was increased after an incorrect response and decreased after a correct response..…”