M. Junaid Amin

Smart laser scanning sampling head design for image acquisition applications

A smart laser scanning sampling head design is presented using an electronically controlled variable focal length lens to achieve the smallest sampling laser spot possible at target plane distances reaching 8 m. A proof-of-concept experiment is conducted using a 10 mW red 633 nm laser coupled with beam conditioning optics that includes an electromagnetically actuated deformable membrane liquid lens to demonstrate sampling laser spot radii under 1 mm over a target range of 20-800 cm. Applications for the proposed sampling head are diverse and include laser machining and component inspection.

CAOS-CMOS camera

Proposed and experimentally demonstrated is the CAOS-CMOS camera design that combines the coded access optical sensor (CAOS) imager platform with the CMOS multi-pixel optical sensor. The unique CAOS-CMOS camera engages the classic CMOS sensor light staring mode with the time-frequency-space agile pixel CAOS imager mode within one programmable optical unit to realize a high dynamic range imager for extreme light contrast conditions. The experimentally demonstrated CAOS-CMOS camera is built using a digital micromirror device, a silicon point-photo-detector with a variable gain amplifier, and a silicon CMOS sensor with a maximum rated 51.3 dB dynamic range. White light imaging of three different brightness simultaneously viewed targets, that is not possible by the CMOS sensor, is achieved by the CAOS-CMOS camera demonstrating an 82.06 dB dynamic range. Applications for the camera include industrial machine vision, welding, laser analysis, automotive, night vision, surveillance and multispectral military systems.

An embedded smart agile pixel imager for lasers

The growing number of laser beam applications in the last few years has created a compelling case for efforts towards track and measure of the profile of laser beams. Laser beam imaging techniques can be embedded through the hardware and software co-design for developing embedded systems at a fraction of the cost, weight and volume and in less time than it would take to develop computer-based alternatives keeping the same accuracy. A smart agile pixel laser beam imager based on an embedded platform is presented in this paper. The design uses a Digital Micromirror Device along with a microcontroller and point photo-detectors to make a compact system having small sized components. This embedded imager is experimentally demonstrated for Gaussian laser beam profiling. The proposed design is suitable for industrial laser based applications requiring accurate two dimensional beam irradiance maps, without needing any attenuating components disrupting the beam.

Optical Shape Sensor Using Electronically Controlled Lens

Proposed is a single viewing axis optical Three-Dimensional (3-D) shape sensor using an electronically controlled variable focus lens (ECVFL) for non-contact smallest transverse resolution reconstructions at all axial direction target planes. The demonstrated completely automated sensor design also involves input beam aperture control for balancing aberration and diffraction effects, enabling minimum focused sampling beam diameter. Sensor design analysis is presented, including the derivation of the depth of field of the camera used in the 3-D sensor. A computer-controlled sensor system using a liquid ECVFL is built and experimentally calibrated for a 40-mm-depth scan with a better than 52 μm transverse resolution over a 400 mm × 400 mm mechanically implemented transverse scan zone. The 3-D sensor system is successfully deployed to measure the borehole depths in a 3-D sample containing 12 boreholes, image the pin regions of a 16-pin Integrated Circuit (IC) ThinShrink Small Outline Package (TSSOP), and reconstruct the shape of a 3-D aircraft part. The sensor gave a ±3% average measurement error for the borehole test sample compared with a vernier caliper measurement. The proposed single viewing axis sensor is ideal for applications requiring cavity or borehole inspections as well as parts requiring high transverse resolution imaging.

Eye vision system using programmable micro-optics and micro-electronics

Proposed is a novel eye vision system that combines the use of advanced micro-optic and microelectronic technologies that includes programmable micro-optic devices, pico-projectors, Radio Frequency (RF) and optical wireless communication and control links, energy harvesting and storage devices and remote wireless energy transfer capabilities. This portable light weight system can measure eye refractive powers, optimize light conditions for the eye under test, conduct color-blindness tests, and implement eye strain relief and eye muscle exercises via time sequenced imaging. Described is the basic design of the proposed system and its first stage system experimental results for vision spherical lens refractive error correction.

Motionless active depth from defocus system using smart optics for camera autofocus applications

This paper describes a motionless active Depth from Defocus (DFD) system design suited for long working range camera autofocus applications. The design consists of an active illumination module that projects a scene illuminating coherent conditioned optical radiation pattern which maintains its sharpness over multiple axial distances allowing an increased DFD working distance range. The imager module of the system responsible for the actual DFD operation deploys an electronically controlled variable focus lens (ECVFL) as a smart optic to enable a motionless imager design capable of effective DFD operation. An experimental demonstration is conducted in the laboratory which compares the effectiveness of the coherent conditioned radiation module versus a conventional incoherent active light source, and demonstrates the applicability of the presented motionless DFD imager design. The fast response and no-moving-parts features of the DFD imager design are especially suited for camera scenarios where mechanical motion of lenses to achieve autofocus action is challenging, for example, in the tiny camera housings in smartphones and tablets. Applications for the proposed system include autofocus in modern day digital cameras.

Agile Wavefront Splitting Interferometry and Imaging using a Digital Micromirror Device

Since 1997, we have proposed and demonstrated the use of the Texas Instrument (TI) Digital Micromirror Device (DMD) for various non-display applications including optical switching and imaging. In 2009, we proposed the use of the DMD to realize wavefront splitting interferometers as well as a variety of imagers. Specifically, proposed were agile electronically programmable wavefront splitting interferometer designs using a Spatial Light Modulator (SLM) such as (a) a transmissive SLM, (b) a DMD SLM and (c) a Beamsplitter with a DMD SLM. The SLMs operates with on/off or digital state pixels, much like a black and white state optical window to control passage/reflection of incident light. SLM pixel locations can be spatially and temporally modulated to create custom wavefronts for near-common path optical interference at the optical detectors such as a CCD/CMOS sensor, a Focal Plane Array (FPA) sensor or a point-photodetector. This paper describes the proposed DMD-based wavefront splitting interferometer and imager designs and their relevant experimental results.

Smart imaging using laser targeting: a multiple barcodes application

To the best of our knowledge, proposed is a novel variable depth of field smart imager design using intelligent laser targeting for high productivity multiple barcodes reading applications. System smartness comes via the use of an Electronically Controlled Variable Focal-Length Lens (ECVFL) to provide an agile pixel (and/or pixel set) within the laser transmitter and optical imaging receiver. The ECVFL in the receiver gives a flexible depth of field that allows clear image capture over a range of barcode locations. Imaging of a 660 nm wavelength laser line illuminated 95-bit one dimensional barcode is experimentally demonstrated via the smart imager for barcode target distances ranging from 10 cm to 54 cm. The smart system captured barcode images are evaluated using a proposed barcode reading algorithm. Experimental results after computer-based post-processing show a nine-fold increase in barcode target distance variation range (i.e., range variation increased from 2.5 cm to 24.5 cm) when compared to a conventional fixed lens imager. Applications for the smart imager include industrial multiple product tracking, marking, and inspection systems.

Smart optical writing head design for laser-based manufacturing

Proposed is a smart optical writing head design suitable for high precision industrial laser based machining and manufacturing applications. The design uses an Electronically Controlled Variable Focus Lens (ECVFL) which enables the highest achievable spatial resolution of writing head spot sizes for axial target distances reaching 8 meters. A proof-of-concept experiment is conducted using a visible wavelength laser with a collimated beam that is coupled to beam conditioning optics which includes an electromagnetically actuated deformable membrane liquid ECVFL cascaded with a bias convex lens of fixed focal length. Electronic tuning and control of the ECVFL keeps the laser writing head far-field spot beam radii under 1 mm that is demonstrated over a target range of 20 cm to 800 cm. Applications for the proposed writing head design, which can accommodate both continuous wave and pulsed wave sources, include laser machining, high precision industrial molding of components, as well as materials processing requiring material sensitive optical power density control.