Abstract-Integration-time-based, time-domain computation provides an area-efficient way to process image information by directly handling photo-created charge during photo-sensing. We have fabricated and tested a CCD-based range-finding sensor which uses the time-of-flight method for range measurement. The sensor exploits two charge packets for light integration and detects the delay of the received light pulse relative to the transmitted light pulse. It has detected a 10 cm distance difference at the range of 150 cm in the dark background.

Electrodeposition of gold into porous silicon was investigated. In the present study, porous silicon with ~100 nm in pore diameter, so-called medium-sized pores, was used as template electrode for gold electrodeposition. The growth behavior of gold deposits was studied by scanning electron microscope observation of the gold deposited porous silicon. Gold nanorod arrays with different rod lengths were prepared, and their surface-enhanced Raman scattering properties were investigated. We found that the absorption peak due to the surface plasmon resonance can be tuned by changing the length of the nanorods. The optimum length of the gold nanorods was ~600 nm for surface-enhanced Raman spectroscopy using a He–Ne laser. The reason why the optimum length of the gold nanorods was 600 nm was discussed by considering the relationship between the absorption peak of surface plasmon resonance and the wavelength of the incident laser for Raman scattering.

As an SERS-active template, Au deposited mesoporous Si was prepared by anodization of Si in hydrofluoric acid solution, followed by the displacement deposition of Au in solution containing Au(S 2 O 3 ) 3À 2 . The size and dispersion of deposited Au particles became small as the concentration of Au ions and the immersion duration decreased. The SERS-activity measured with rhodamine 6G as the target molecule was affected by the morphology of Au deposits.

We have implemented two analog VLSI computational sensors for sensing and encoding high dynamic range images by exploiting temporal dimension of photoreception. The first sensor is a multi-integration time photoreceptor that automatically adapts to use different integration periods depending on light intensity. It exhibits a dynamic range 128 times larger than that of a single integration period photoreceptor, approximately 1: 128 OOO. The second sensor is an intensity-to-time processing paradigm that is based o n the notion that stronger stimuli elicit responses before weaker ones. The paradigm sorts pixels of sensed images by their intensities, thus achieving information-theoretic optimal encoding of images. It handles dynamic range of approximately 1 : 1 OOO OOO. Both implementations can operate at standard video rate of 30 frames s -' . 0 1998 Elsevier Science Ltd. All rights reserved.