Calculating Global Overlap Windows in Sequential Row Readout Image Sensors
Calculate global overlap by subtracting array readout time from total exposure; fire external illumination within this window to emulate global shuttering.
Line Quantization
Spatial Error
Discrete steps used to represent the position or intensity of a signal along a single axis of an image sensor introduce a fundamental limit on the resolution of the data. This line quantization occurs when a continuous physical value is mapped onto a finite number of digital levels. The precision of the analog to digital converter dictates how small these steps are.
Aliasing Effect
High frequency details that are smaller than the sampling interval appear as false patterns or jagged edges in the final output. Sharp transitions in light intensity become stepped gradients due to line quantization during the sampling process. Optical low pass filters are often used to blur these edges before they reach the sensing array.
Bit Depth
Increasing the number of bits allocated to each pixel allows for a finer representation of the original signal. Low bit depth results in visible banding where the line quantization steps are large enough to be seen by the eye. Scientific sensors use fourteen or sixteen bits to ensure that the smallest changes remain visible.
Noise Interaction
Random fluctuations in the signal can sometimes mask the rounding errors by dithering the values across the digital boundaries. This effect prevents the line quantization from creating hard artifacts in dark areas of the image.