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.
Horizontal Line Period
Signal Timing
The time interval required to scan a single row of pixels dictates the fundamental rhythm of a video or sensor stream. Every horizontal line period consists of the active signal time and a blanking interval used for synchronization or internal sensor calibration. This parameter is a fixed constant in many standard definition and high definition formats.
Clock Cycle
High frequency pulses from a master oscillator define the length of the individual pixel windows within the row. The horizontal line period is calculated by multiplying the number of pixels in a line by the duration of one clock cycle plus any overhead.
Bandwidth Requirement
Faster scanning reduces the time available for each row and necessitates higher data transfer rates. Shifting the horizontal line period to a lower value increases the frame rate but requires the amplification circuits to have a wider frequency response to avoid signal blurring. This increase in bandwidth can introduce more noise into the system which requires better filtering to maintain image quality.
Frame Synthesis
Vertical resolution depends on the number of lines that can be processed within the total frame time. The horizontal line period must be small enough to allow for the desired row count while providing enough time for the analog signals to stabilize before digitisation.