System and method for calibrating the light sensitivity of a camera

A calibration system for calibrating a light sensitivity of a camera used in aerospace lightning testing, comprising:

• a light emitter configured to emit a light pulse therefrom;
• a fiber splitter having an input port, a first output port and a second output port, wherein the fiber splitter is configured to receive the light pulse via the input port and to provide a first portion of the light pulse to the first output port and a second portion of the light pulse to the second output port according to a splitting ratio, wherein the first portion is greater than or equal to the second portion;
• a light collector configured to receive the first portion from the first output port and convert the first portion to a first signal that is representative of a light characteristic of the first portion;
• a first fiber optic cable operatively connecting the light emitter and the input port;
• a second fiber optic cable operatively connecting the first output port and the light collector;
• a third fiber optic cable having opposed first and second cable ends, wherein the first cable end is operatively connected with the second output port and the second cable end is configured for emitting the second portion of the light pulse therefrom across a predetermined distance for capture by the camera;
• a fixture apparatus including a cable fixture for mounting the second cable end at a first location and a camera fixture for mounting the camera at a second location, such that when the second cable end is mounted in the cable fixture and the camera is mounted in the camera fixture, thereby defining a line-of-sight between the second cable end and the camera, the second cable end is pointed generally toward the camera and is disposed at the predetermined distance from the camera;
• a light isolation chamber extending along and at least partially enclosing the line-of-sight;
• and
• a controller operatively connected to the light emitter for controlling a pulse timing of the light emitter and to the light collector for receiving the first signal from the light collector.

A method for calibrating a light sensitivity of a camera, comprising:

• positioning the camera at a predetermined distance from and pointing generally toward a light emission point of a calibration system, wherein the calibration system includes:
• a light emitter configured to emit a light pulse therefrom;
• a fiber splitter having an input port, a first output port and a second output port, wherein the fiber splitter is configured to receive the light pulse via the input port and to provide a first portion of the light pulse to the first output port and a second portion of the light pulse to the second output port according to a splitting ratio, wherein the first portion is greater than or equal to the second portion;
• a light collector configured to receive the first portion from the first output port and convert the first portion to a first signal that is representative of a light characteristic of the first portion;
• a first fiber optic cable operatively connecting the light emitter and the input port;
• a second fiber optic cable operatively connecting the first output port and the light collector;
• and
• a third fiber optic cable having opposed first and second cable ends, wherein the first cable end is operatively connected with the second output port and the second cable end is the light emission point and is configured for emitting the second portion of the light pulse therefrom;
• opening a shutter of the camera;
• causing the light emitter to emit the light pulse;
• receiving the first portion by the light collector and the second portion by the camera;
• closing the shutter after the light pulse reaches a peak intensity plus a predetermined fall time;
• converting the first portion to the first signal by the light collector and converting the second portion to a second signal by the camera which is representative of the light characteristic of the second portion;
• repeating the opening, causing, receiving, closing and converting steps to produce multiple instances of the light pulse, a first set of multiple instances of the first signal and a second set of multiple instances of the second signal;
• creating a first data set based on the first set and a second data set based on the second set;
• determining a first average for the first data set and a second average for the second data set;
• and
• comparing the first and second averages with each other using a comparison algorithm to estimate the light sensitivity of the camera.