Cost-effective image acquisition system for precise PC-based measurement

Image sensors based on the CMOS technology became commonly used sources of image information in PC-based vision systems. Image information is converted directly on the chip to a stream of synchronous digital data which can be transferred to a PC using the cost-effective interface introduced in this contribution. The CMOS image sensor together with the developed interface can be considered as a simple image acquisition system - USB camera matching all features of distributed image acquisition and processing model described in this article. Concept of the USB camera is enhanced by additional data merged with each image frame transferred to the PC. This feature makes the developed device suitable for tasks where the precise timing of image acquisition together with an external synchronization is required. Based on the VHDL model of the used CMOS image sensor and the designed PC interface with the USB driver, the critical timing and maximal USB data throughput limitations are analyzed and discussed.