Characterization and evaluation of optical elements under vibrational loading

A testing system comprising:

• a means for vibrational loading (MVL) including lateral sinusoidal movement;
• a means for controlling said MVL based on a first plurality of user inputs comprising one or more frequency of vibration associated with one or more MVL vibration instances specified in cycles of said MVL per unit of time, a dwell time for each said one or more frequency, and an amplitude of position or acceleration for each said one or more said one or more frequency;
• a means for fixing a system under test (SUT) to said MVL, said SUT comprising an optical element and an imaging system coupled with said optical element to receive light through said optical element;
• a means for detecting acceleration from said MVL and outputting a first acceleration signal;
• an illumination target (IT) means comprising a light source configured to generate and pass light through said optical element, said IT means partially blocks said light source and generates a pattern of said light comprising a plurality of equally spaced grid patterned light having first and second light intensities;
• a test control (TC) means for processing said first acceleration signal to generate a trigger signal produced when said first acceleration signal is at a first voltage threshold and generate a light source activation signal for operating said IT means;
• an electro-optics control (EOC) means for controlling said TC means, said imaging system of said SUT based in part on said trigger signal, said one or more frequency of vibration, said dwell time, and a second plurality of user inputs, said second plurality of user inputs comprising one or more phase delays of vibration cycle to IT means pulse occurrence defining a phase delay between vibration cycle start and an activation of said light source, a pulse width defining a duration of operation for said light source, a frame rate for image capture from said imaging system, and a black level for defining a low light pixel signal value added to all said imaging system's pixel output, wherein said EOC synchronizes said light illumination means output with said MVL loading based on said trigger signal, wherein said EOC section further configured for recording a plurality of test data from said imaging system;
• and
• a processing means for real-time or post-processed optical characterization of said test data comprising images from each said image capture, performing analyses on said images comprising means for generating a SUT distortion analysis output using distortion mapping results to create an analytical output comprising graph data shown as a function of vibration frequency to show a determination of effect of relative motion within at least said optical element based on comparing a predetermined warping tolerance in predetermined applications comprising a measurement of a predefined human capability for distinguishing objects in image outputs from said SUT at a predetermined distance or a predetermined resolution value, and displaying results of said analyses of said images on said display comprising said measurement of said predefined human capability for distinguishing objects in said image outputs or a resolution metric of said images.

A method of testing providing a testing system comprising:

• a first support structure;
• a second support structure;
• at least one display;
• a vibration loading system (VLS) operable to generate vibrational loading, said VLS is supported by said first support structure, wherein said VLS further comprises a vibration isolation structure adapted to enable lateral movement of a VLS support section and attenuate or reduce vibration transmitted from said VLS to said first support structure;
• a VLS control system section comprising a first recording medium section configured to store a first plurality of non-transitory machine readable instruction configured to control said VLS based on a first plurality of user inputs comprising one or more frequency of vibration associated with one or more VLS table vibration instances specified in cycles of said VLS per unit of time, a dwell time for each said one or more frequency, and an amplitude for each said one or more frequency;
• a mounting structure adapted to receive a System Under Test (SUT) comprising an optical element and imaging system configured to receive light through said optical element, said mounting structure couples the SUT with the VLS support structure, wherein said mounting structure includes a first and second clamp section each having a recessed section facing the SUT configured to receive an adjustable focus ring section of said optical element so as to apply clamping force on optical element areas adjacent to said focus ring while said optical element is clamped within said mounting structure;
• a first acceleration sensor coupled with the VLS configured to provide VLS acceleration data;
• a first Illumination Target System (ITS) comprising a light source configured to generate and pass light through said optical element, said first ITS is supported by the second support structure, said second support structure is spaced apart from said first support structure, wherein said first ITS further comprises a distortion target comprising a transparent glass with a fixed spacing grid or pattern of light absorbing or opaque structures;
• a Test Control System (TCS) comprising a signal buffer configured to receive said VLS acceleration data, a band pass filter receiving inputs from said signal buffer, and amplifier receiving inputs from said band pass filter, and a zero crossing detector receiving inputs from said amplifier that outputs a trigger signal output when said amplifier signal is above a first voltage threshold, said TCS further comprising a light source driver generating a power signal to said ITS to power and control said light source, wherein said first acceleration sensor provides said VLS acceleration data;
• an Electro-Optics Control Computer (EEOC) section comprising a data acquisition section coupled to said signal buffer and said zero crossing detector, said EEOC further comprising a second recording medium section configured to store a second plurality of non-transitory machine readable instructions configured for controlling said EEOC section, said TCS, and said imaging system based on said trigger signal output from said zero crossing detector, said signal buffer output receiving said acceleration data, one or more frequency of vibration, said dwell time, and a second plurality of user inputs, said second plurality of user inputs comprising a list of one or more phase delays of vibration cycle to ITS pulse occurrence defining a phase delay between vibration cycle start and an activation of said light output from said ITS, a pulse width defining a duration of operation for said light that is output from said ITS, a frame rate for image capture from said imaging system, and a black level for defining a low light pixel signal value added to all said imaging system's pixel output to adjust for pixel outputs below a first signal intensity measurement level to avoid clipping said pixel outputs below said first signal intensity measurement level and zero output from one or more of said imaging system's pixels, wherein said EEOC synchronizes said light source driver with VLS position based on said zero crossing detector output, wherein said EEOC section further configured for recording a plurality of test data from said imaging system;
• a processing section configured for real-time or post-processed optical characterization of said test data comprising images from each said image capture, said post processing section comprising a plurality of non-transitory machine readable instructions stored on a non-transitory storage medium configured for performing analyses on said images comprising generating a first distortion analysis output to create a distortion mapping result (DMR) analytical output comprising a percentage difference or displacement from imaged said grid or pattern of light absorbing or opaque structures compared to positions of said grid or pattern of light absorbing or opaque structures, storing said DMR, creating a second distortion analysis output comprising said DMR data shown in a graph on said display as a function of vibration frequency, creating a third distortion analysis output comprising a comparison of said DMR data with a predetermined distortion or warping tolerance in predetermined applications comprising distinguishing objects viewed through said SUT at a predetermined distance or a predetermined resolution value;
• inputting said first and second plurality user inputs into said VLS control system and said EEOC system;
• running one or more VLS sequences in accordance with a plurality of control instructions stored on said EEOC or said VLS control system based on said first and second plurality of user input data, said VLS sequence comprises control instructions to operate VLS to ramp up said VLS to a predetermined acceleration amplitude and frequency and then wait at that amplitude for an appropriate dwell time using said first accelerometer for feedback control;
• then decelerate down to rest;
• then increments to a next value in said first plurality of user inputs and repeating at least some of programmed control instructions based on a set of incremented values;
• reading accelerometer amplitude and frequency comprising determining if a measured VLS frequency matches a selected said frequency of vibration, wherein if a match exists, then execute a delay for a transient delay time or if no, recommence processing;
• setting said first ITS and said SUT imaging system parameters;
• calculating image capture time for controlling the SUT imaging system using said dwell time, said transient delay time, and a number of phase values in said list of said phase delays;
• incrementing to next a value in a list of said list of phase values comprising a phase vector;
• operating said light source to generate strobed said light source output at a respective user input phase delay value with said trigger signal from said zero crossing detector with a non-transitory machine readable instruction or software defined delay and pulse width control;
• capturing and saving said images received through said SUT optical element and captured by said imaging system for a duration of time equal to image capture time defined by said dwell time divided by a number of phases in said phase values minus said transient delay;
• and
• executing said post processing section to generate said first, second and third distortion analysis output.