Height Reconstruction
Mathematical reconstruction of three-dimensional surface profiles from phase-shifted light patterns is a core component of modern solder paste inspection. The process of phase unwrapping compute resolves the modular ambiguity inherent in phase measurements to determine the absolute height of the deposited solder paste. Because the phase is initially calculated only within a single cycle of the light pattern, this mathematical operation reconstructs the true height by adding or subtracting integer multiples of the wavelength.
It converts raw phase maps into a continuous height profile of the printed board.
Algorithmic Efficiency
Processing these phase arrays demands high-performance algorithms to handle millions of pixels per second during inline inspection. Noise in the image or sharp height discontinuities on the board surface can lead to phase errors that propagate across the calculation, resulting in height artifacts. Spatial unwrapping algorithms compare adjacent pixels to detect phase steps, while temporal unwrapping utilizes multiple fringe frequencies to resolve heights independently at each pixel.
This latter method provides greater accuracy but significantly increases the volume of calculations required to generate each 3D image.
Hardware Acceleration
Graphics processing units are typically used to execute these calculations in parallel. This hardware-level optimization enables the 3D inspection system to output height and volume metrics in real time. Fast execution ensures that the assembly line is not delayed by computational limits.
