Netherlands semiconductor equipment manufacturer ASM International NV has announced that COO Daniel Queyssac will retire in September. Han Westendorp, ASM's general manger, has been appointed COO, effective immediately; Queyssac will serve as an advisor in the interim.   . . .   Sunnyvale, Calif.-based OmniVision Technologies Inc., which makes CMOS CameraChips for high-volume imaging applications, said it will supply Pantech & Curitel, a supplier of camera-enabled handsets, with custom CameraChip modules in volume to be embedded in mobile phone platforms.   . . .   The class-action lawsuit against Computerized Thermal Imaging Inc., maker of medical imaging systems, alleging violations of the Securities Act was dismissed by the US District Court in Oregon on April 17.