Recovery of Oversaturated Pixels in a Low-Cost Solder Paste Inspection Setup

Solder paste inspection (SPI) devices have been used in the SMT assembly line in consideration of advantages such as obtaining good quality products, reducing cost, and cutting diagnosis time. In this regard, we build a low-cost SPI based on the structured light procedure. Subsequently, we have to accept a trade-off because of the economical components cause undesirable effects. One of them is oversaturated occurrence in shiny surfaces such as solder-pastes, which are considered in this article. Our impetus is to attenuate the undesirable consequences of oversaturated pixels in the final step, which assess solder paste quality and detect height defects based on 3D reconstruction. The phase-shifting profilometry, one of the structured light method for 3D reconstruction, is considered in this work. This paper aims to apply image processing algorithms to captured images and assessing phase-map in the interest of conquering undesirable effects and recovery of the oversaturated pixels.