Image Sensor with Focal Plane Extraction of Polarimetric Information

A novel focal plane imaging sensor capable of real time extraction of polarization information is presented. The imaging system consists of a photo array of 256 by 256 linear current mode active pixel sensors (APS). Analog processing circuitry is included at the focal plane for noise suppression and computation of the Stokes parameters. The imaging sensor was fabricated in 0.18μm process with 10μm pixel pitch and 75% fill factor. An array of micro polarizer is designed and fabricated separately and will be mounted on top of the imaging array. Simulation results of the imaging sensor are presented

A CMOS Linear Voltage/Current Dual-Mode Imager

We present a CMOS image sensor capable of both voltage- and current-mode operations. Each pixel on the image has a single transistor acting as either source follower for voltage readout, or transconductor for current readout. The two modes share the same readout lines, but have their own correlated double sampling (CDS) units for noise suppression. We also propose a novel current-mode readout technique using a velocity saturated short-channel transistor, which achieves high linearity. The 300x200 image array is a mixture of 3 types of pixels with identical photodiodes and access switches; while the readout transistors are sized for their designated mode of operation. This ensures a fair comparison on the performance of the different modes

Low Fixed Pattern Noise Current-mode Imager Using Velocity Saturated Readout Transistors

This paper described a novel current-mode active pixel sensor (APS) imager. Conversion of photodiode voltage to output current is done using transistors operating in velocity saturation region. The high output impedance of this region makes it more suitable for current-sourcing operation than the linear region. The transistors also exhibit high linearity, allowing us to suppress fixed pattern noise (FPN) by correcting for both offset and gain variations among pixels. Experimental results on the fabricated 110×200 pixel array are presented. With conventional correlated double sampling (CDS), FPN is reduced from 3.8% to 0.85%. Further reduction requires compensation of gain variations, and results in a final FPN of 0.19%. A triple sampling approach is introduced to implement the described correction in hardware

Image Sensor with General Spatial Processing in a 3D Integrated Circuit Technology

An architectural overview of an image sensor with general spatial processing capabilities on the focal plane is presented. The system has been fabricated on two separate tiers, implemented on silicon-on-insulator technology with vertical interconnect capabilities. One tier is dedicated to imaging, where photosensitivity and pixel fill have been optimized. The subsequent layers contain noise suppression and digitally controlled analog processing elements, where general spatial filtering is computed. The digitally controlled aspect of the processing unit allows generic receptive fields to be computed on read out. The image is convolved with four receptive fields in parallel. The chip provides parallel readout of the filtered results and the intensity image

Two Transistor Current Mode Active Pixel Sensor

A novel current mode active pixel sensor for high resolution imaging is presented. The photo pixel is composed of a photodiode and two transistors: reset and transconductance amplifier transistor. The switch transistor is moved outside the pixel, allowing for lower pixel pitch and increased linearity of the output photocurrent. The increased linearity of the image sensor has greatly reduced spatial variations across the image after correlated double sampling and the column fix pattern noise is 0.35% of the saturated current. A discussion on theoretical temporal noise limitations of this design is also presented

Fabrication of a Dual-Tier Thin Film Micro Polarization Array

A thin film polarization filter has been patterned and etched using reactive ion etching (RIE) in order to create 8 by 8 microns square periodic structures. The micropolarization filters retain the original extinction ratios of the unpatterned thin film. The measured extinction ratios on the micropolarization filters are ~1000 in the blue and green visible spectrum and ~100 in the red spectrum. Various gas combinations for RIE have been explored in order to determine the right concentration mix of CF4 and O2 that gives optimum etching rate, in terms of speed and under-etching. Theoretical explanation for the optimum etching rate has also been presented. In addition, anisotropic etching with 1μm under cutting of a 10μm thick film has been achieved. Experimental results for the patterned structures under polarized light are presented. The array of micropolarizers will be deposited on top of a custom made CMOS imaging sensor in order to compute the first three Stokes parameters in real time

Linear Current-Mode Active Pixel Sensor

A current mode CMOS active pixel sensor (APS) providing linear light-to-current conversion with inherently low fixed pattern noise (FPN) is presented. The pixel features adjustable-gain current output using a pMOS readout transistor in the linear region of operation. This paper discusses the pixel’s design and operation, and presents an analysis of the pixel’s temporal noise and FPN. Results for zero and first-order pixel mismatch are presented. The pixel was implemented in a both a 3.3 V 0.35 µm and a 1.8 V 0.18 µm CMOS process. The 0.35 µm process pixel had an uncorrected FPN of 1.4%/0.7% with/without column readout mismatch. The 0.18 µm process pixel had 0.4% FPN after delta-reset sampling (DRS). The pixel size in both processes was 10 X 10 µm2, with fill factors of 26% and 66%, respectively

Identification of Sentinel Lymph Node in Breast Cancer with three Tracers (Radiocolloid, Methylene blue, and Indocyanine Green). (Case Report)

BACKGROUND: Sentinel lymph node (SNL) biopsy in breast cancer for the determination of axillary status is standard procedures in surgical treatment of early-stage breast cancer. The identification of the SNL is usually performed by radiocolloid injection or/and injection of methylene blue due. The use of indocyanine green (ICG) dye, which is fluorescent dye, which movement in breast and axillar pit, can be followed with special cameras which detect near infrared specatar of light. CASE REPORT: In this paper, we present case report of patient with breast cancer, where we perform SNL detection with three methods: Use of radiocolloid which we trace with static gamma camera, and intraoperatively with hand held gamma probe, methylene blue dye which movement we followed by eye contact and using indocyanine green which movement was followed by specially constructed multispectral camera, which can detect near-infrared fluorescence that is emitted by ICG and methyline blue, respectively. CONCLUSION: Fluorescent imaging with ICG is a sensitive, valuable, and safe method for SNL biopsy. Finding new agents that would identify the SNL, especially if they are not radioactive would be an important step in wider application of this method

Fluorescence-guided surgical system using holographic display: From phantom studies to canine patients

SIGNIFICANCE: Holographic display technology is a promising area of research that can lead to significant advancements in cancer surgery. We present the benefits of combining bioinspired multispectral imaging technology with holographic goggles for fluorescence-guided cancer surgery. Through a series of experiments with 43D-printed phantoms, small animal models of cancer, and surgeries on canine patients with head and neck cancer, we showcase the advantages of this holistic approach. AIM: The aim of our study is to demonstrate the feasibility and potential benefits of utilizing holographic display for fluorescence-guided surgery through a series of experiments involving 3D-printed phantoms and canine patients with head and neck cancer. APPROACH: We explore the integration of a bioinspired camera with a mixed reality headset to project fluorescent images as holograms onto a see-through display, and we demonstrate the potential benefits of this technology through benchtop and RESULTS: Our complete imaging and holographic display system showcased improved delineation of fluorescent targets in phantoms compared with the 2D monitor display approach and easy integration into the veterinarian surgical workflow. CONCLUSIONS: Based on our findings, it is evident that our comprehensive approach, which combines a bioinspired multispectral imaging sensor with holographic goggles, holds promise in enhancing the presentation of fluorescent information to surgeons during intraoperative scenarios while minimizing disruptions