A 128 128 CMOS imager that permits synchronous capture is presented. The sensor combines the best of CMOS imagers (low-power, random readout, nondestructive readout, single supply voltage…) and synchronous capture [available in high-end charge coupled device (CCD) imagers]. The key point in obtaining such characteristics is the separation of the photosensor and the storage element. Although some sensors with these characteristics have been reported, in this sensor, the storage capability has been brought a step further, having storage times in the order of tens of seconds, and being able to use the array itself as a random access memory (RAM). This could avoid the use of external RAM, making the system simpler, more compact, and of low-power consumption.Index Terms-Active pixel sensor, analog memory, CMOS image sensors, machine vision.

This paper presents a novel column-parallel readout circuit for image sensors based on incremental-sigma-delta (ISD) ADCs. The excessive number of clock cycles needed per conversion is addressed. We apply the Photon Transfer Curve (PTC) based conversion to a second-order ISD ADC, achieving a 2.75x clock cycles reduction when compared to a standard secondorder ISD ADC while maintaining the same noise performance. This results in the reduction of the pixel readout time and of the size of the digital filter.

Absiract -This paper presents a prototype of a mobile minirobot with an embedded vision system. The robot control is implemented in a low cost microcontroller and the vision system is based in a proprietary CMOS imaging array. The proposed vision sensor has enough flexibility to be incorporated directly to most microcontroller-based systems without any additional electronics. The CMOS camera sensor has random access readout capabilities and the microcontroller uses the camera like B read only external memory. Therefore, the main advantage of this system is that image-processing algorithms can be incorporated directly in a low cost microcontroller, resulting on a compact vision system with decision-making capabilities. The robot autonomous capabilities have been tested in a soccer game scenario where visual tasks as object localisation and classification are needed.

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