Overview of coded light projection techniques for automatic 3D profiling
---
paper_title: Range image acquisition with a single binary-encoded light pattern

paper_content:

The problem of strike identification in range image acquisition systems based on triangulation with periodically structured illumination is discussed. A coding scheme is presented based on a single fixed binary encoded illumination pattern, which contains all the information required to identify the individual strikes visible in the camera image. Every sample point indicated by the light pattern is made identifiable by means of a binary signature, which is locally shared among its closest neighbors. The applied code is derived from pseudonoise sequences, and it is optimized so that it can make the identification fault-tolerant to the largest extent. A prototype measurement system based on this coding principle is presented. Experimental results obtained with the measurement system are also presented. >
---

Title: Overview of coded light projection techniques for automatic 3D profiling

Section 1: INTRODUCTION
Description 1: Introduce the importance of automatic 3D reconstruction in various applications and the role of coded structured light in simplifying correspondence problems in stereovision systems. Discuss the aim and structure of the paper.

Section 2: CLASSIFICATION OF CODED PATTERNS
Description 2: Explain the different pattern projection techniques based on their codification strategies, including spatial, temporal (time-multiplexing), and direct codification. Discuss the features indicating the suitability of patterns for measuring moving objects, color depth, and whether repeated codewords appear.

Section 3: SPATIAL NEIGHBORHOOD
Description 3: Detail the techniques that concentrate coding schemes in a unique pattern, using information from a neighborhood of pixels.

Section 4: Non-formal codification
Description 4: Summarize early spatial neighborhood techniques that did not use formal codification theories and relied on brute-force algorithms.

Section 5: Patterns encoded with De Bruijn sequences
Description 5: Discuss the methods that use orthogonal slits color encoded with De Bruijn sequences, highlighting robustness against repeated neighborhoods.

Section 6: Patterns encoded with M-arrays
Description 6: Explain the extension of pseudorandom sequences to bidimensional cases, using M-arrays with window properties for coding patterns.

Section 7: TIME-MULTIPLEXING
Description 7: Describe temporal coding techniques where a sequence of patterns is projected over time, forming codewords for pixels based on illuminance values across patterns.

Section 8: Patterns based on binary codes
Description 8: Discuss techniques using black and white codes for pattern points, including Gray code extensions.

Section 9: Gray code and Phase shifting
Description 9: Explain methods combining Gray code with multistripe patterns for ambiguity resolution and increased resolution through phase shifting.

Section 10: Hybrid methods
Description 10: Describe techniques that combine time-multiplexing with spatial neighborhood coding for dynamic scenes.

Section 11: DIRECT CODIFICATION
Description 11: Detail direct coding techniques that allow pixel coordinates to be obtained directly from pattern information, using large color ranges or periodicity.

Section 12: Coding based on grey levels
Description 12: Explain methods using grey levels to encode patterns, such as intensity ratio sensors and sawtooth sensors, and their advantages.

Section 13: Color based coding
Description 13: Summarize techniques using color for pattern encoding, including rainbow patterns and multispectral pattern projection, and their specific applications.

Section 14: CONCLUSIONS
Description 14: Provide an exhaustive classification summary of coded structured light techniques and discuss their suitability for different applications, emphasizing the trade-off between patterns, colors, acquisition time, and accuracy.

Section 15: ACKNOWLEDGMENTS
Description 15: Acknowledge the funding sources and contributors to the research work.