SENSORS OPTIMIZED FOR 3D DIGITIZATION ARYA MURALI S7EA 08119

Transcription

1 SENSORS OPTIMIZED FOR 3D DIGITIZATION ARYA MURALI S7EA 08119

2 CONTENTS Introduction 3-D imaging Technology Sensors For 3-D imaging Proposed Sensors Case Implementation Advantages Applications Future Scope Conclusion Reference

3 INTRODUCTION ØDigital 3D imaging can benefit from advances in VLSI technology in order to accelerate its deployment in many fields like visual communication and industrial automation ØHigh-resolution 3D images can be acquired using laserbased vision systems. Ø Optimization of sensors means integrating them as small chips, which accelerate the development of imaging devices.

4 3D IMAGING TECHNOLOGY Machine Vision It analyses the properties of luminous flux reflected by the object. There are two types of methods for finding the structure and dimension they are 1. Passive Vision 2. Active Vision

5 Passive Vision Analyses the structure under ambient light Produces uncertainty in imaging Active Vision q Reduces the uncertainty by structuring the image q It eliminates most of the irregularities found in 2-D imaging q This method is sensitive to each and every micro structure q Triangulation based laser range cameras are examples of active vision technique.

6 AUTOSYNCHRONIZED SCANNER It utilizes triangulation technique for imaging

7 SENSORS FOR 3-D IMAGING Two types 1.Synchronization Circuit Based Upon Dual Cells o Ensures the stability and repeatability in range measurement on varying temperature othese are bulky oon integrating reduces size of devices used for 3-D digitization

8 2. Optimized 3-D position sensor vposition sensors measures position of light spot in one or two dimension. v Specification of 2-D position sensors will be different from 3-D. vin 3-D a small spot of noise means large amount of pixels which is not compactable with 2-D imaging. v When VLSI technologies are implemented 3-d imaging become widely accepted

9 POSITION SENSITIVE DETECTOR Position Sensitive Detector (PSD) is an optical position sensor (OPS), that can measure a position of a light spot in one or two-dimensions on a sensor surface. The PSD is a precision semiconductor optical sensor which produces output currents related to the centre of mass of light incident on the surface of the device.

10 DUAL AXIS PSD This particular PSD is a five terminal device bounded by four collection surfaces; one terminal is connected to each collection surface and one provides a common return. Photocurrent is generated by light which falls on the active area of the PSD will be collected by these four perimeter electrodes.

11 PROPOSED SENSORS Based on the way light spot sensed two types 1.CRPSDs ücontinuous Response Position Sensitive Detectors üit includes lateral effect photodiode and geometrically shaped photodiodes üused for color identifying 2. DRPSDs üdiscrete Response Position Sensitive Detectors ücomposed of detectors, charge coupled device, array of photo diodes equipped with a MUX.

12 CASE IMPLEMENTATION OVER ALL ARCHITECTURE

13 CHIP DESIGN OF ONE SUCH DRPSDs Contains an array of optical sensor It has a variable gain channel with a read out window of 16 neighboring pixels Pixel area of 48 x 500micrometer square Pixel dimension too large so that it can handle spots of noise

14 SENSORS ON 3D DIGITIZATION ADVANTAGE: v Reduced size and cost v Better resolution at a lower system cost v High reliability that is required for high accuracy 3D vision systems v Complete images of visible surfaces that are rather featureless to the v Human eye or a video camera can be generated DISADVANTAGES:- v The elimination of all stray light in an optical system requires sophisticated

15 APPLICATIONS Intelligent digitizers will be capable of measuring accurately and simultaneously color and 3D For the development of hand held 3D cameras Multi resolution random access laser scanners for fast search and tracking of 3D features

16 FUTURE SCOPE Anti reflecting coating film deposition and RGB filter deposition can be used to enhance sensitivity and for colour sensing.

17 CONCLUSION The results obtained so far have shown that optical sensors have reached a high level of development and reliability those are suited for high accuracy 3D vision systems. The availability of standard fabrication technologies and the acquired know-how in the design techniques, allow the implementation of optical sensors that are application specific: Opto-ASICs. The trend shows that the use of the low cost CMOS technology leads competitive optical sensors.

18 REFERENCES L.GONZO, A.SIMONI, A.GOTTARDI, DAVID STAPPA, J.A BERNALDIN, Sensors optimized for 3D digitization, IEEE transactions on instrumentation and measurement, vol 52, no.3, June 2003, pp P.SCHAFER, R.D.WILLIAMS. G.K DAVIS, ROBERT A. ROSS, Accuracy of position detection using a position sensitive detector, IEEE transactions on instrumentation and measurement, vol 47, no.4, August 1998, pp l l

19 Q&A