The Smart Laser Projector’ (SLP) is a modified laser-based projector capable of displaying graphics on a variety of non-prepared surfaces, while simultaneously using the beam (at the same or different wavelength or polarization) as a LIDAR probe gathering information about that surface position, orientation and shape, fine texture, spectral reflectance and even relative motion. It is therefore possible to synthesize an artificial surface reflectance, or to correct geometrical warp, all in real time and without the need of calibrating a camera and a projector. We have developed two prototypes, one working in raster-scan mode, and another in vector graphics mode.
Our previous research on the Smart Laser Scanner [2005], scoreLight and Sticky Light can be seen as special applications of the SLP in vector-graphics mode.
Applications of the SLP may include dermatology (enhancement of superficial veins or direct visualization of anomalous polarization induced by cancerous cells), non-destructive control (visualization of microscopic scratches, oily spots or mechanical stress), authentication (visualization of non-fluorescent UV or IR watermarks thanks to ‘artificial fluorescence’), and in general all sort of augmented reality applications using any available surface for projection (tables, desktops, walls and floors, but also human skin, printed material and paintings, market products on a shelf, etc). Augmentation means here overlaying of alphanumeric data or icons over real object (for instance, human-readable price tags appearing under machine-readable barcodes), dynamic cueing (marking secure perimeters, indicate directions or highlighting dangerous obstacles) and line and contour enhancement for practical or aesthetic purposes.
The laser-based ‘sensing display’ paradigm presents a number of advantages with respect to the more classical `projector-camera’ setup used in sensor-enhanced displays, among which:
- no camera-projector calibration needed (perfect registation by construction);
- very fast feedback (no image processing required);
- geometrical correction + color and contrast compensation possible;
- extremely large depth of field;
- variable resolution: the laser scanning step can be finer on regions of interest;
- simple and compact optical system: there is no 2d imaging optics, and hence no aberrations nor bulky optics;
- projection at very long distance in vector graphics mode ideal for outdoor interactive applications.
- Input/Output capabilities (the projected text can be “touched” to respond)
A MEMS based, compact SLP may eventually be embedded on clothes and used as a wearable display capable of transforming on-the-flight any surface near-by into a full interactive ‘sensing display’.
References
- A. Cassinelli, A. Zerroug, J. Angesleva and M. Ishikawa, “Camera-less Smart Laser Projector”, Laval Virtual – 12th Virtual Reality International Conference / ReVolution Demos, April 7-11 2010, Laval, France. Additional (handout), Poster). [SIGGRAPH E-tech Revolution Award: invited to SIGGRAPH E-Tech 2010].
- A. Cassinelli, A. Zerroug, Y. Watanabe, J. Angesleva and M. Ishikawa, “Camera-less Smart Laser Projector”, SIGGRAPH 2010 (invited to Emerging Technologies). July 25-29 2010, Los Angeles. One paper abstract. Flyer.
- Laser Sensing Display & scoreLight shown at the JST Symposium in conjunction with IEEE VR2011, Suntec Convention Center, SINGAPORE (20-27.3.2011) [poster 1 / poster 2]