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In this paper, we present a novel interpolation technique for the division of focal plane polarization image sensors, which adaptively determines the polarization residuals of a pixel in four directions. We have analyzed the performance of different micro-polarizer patterns by interpolation and optimized for a polarization microscope with maximized interpolation accuracy. Specifically, we applied our proposed algorithm on patterns of four micro-polarizers (oriented along 90°, 135°, 45°, and 0°), three micro-polarizers (oriented along 0°, 45°, and 90°), and two micro-polarizers (oriented along 0° and 45°), respectively. The experimental results reveal that the three-micro-polarizer pattern outperforms the other micro-polarizer patterns for recovering the missing polarization information in terms of mean square error (MSE). Moreover, the visual comparison is enabled with the fibrous structure of human liver carcinoma tissues, which shows excellent agreement with the reported MSE comparison. [ABSTRACT FROM AUTHOR]

The field of astronomy relies on spectral and polarization imagery recorded across a wide range of spectra to make inferences about imaged objects from nearby and distant galaxies. One of the challenges in recording celestial polarization information is recording multiple images filtered with various polarization optics, such as linear polarization filters or retarders, and with low-noise, low-dark-current sensors. In this paper, we present a division of focal plane polarimeter that can operate at room temperature down to −20 °C. When the imaging sensor operates at −20 °C, the dark currents is reduced by two orders of magnitude, which improves the polarization extinction ratio by ~5-fold. Comprehensive optoelectronic tests are presented with data recorded with the polarimeter. [ABSTRACT FROM PUBLISHER]

Fluorescently guided minimally invasive surgery is improving patient outcomes and disease-free survival, but biomarker variability hinders complete tumor resection with single molecular probes. To overcome this, we developed a bioinspired endoscopic system that images multiple tumor-targeted probes, quantifies volumetric ratios in cancer models, and detects tumors in ex vivo samples. We present a new rigid endoscopic imaging system (EIS) that can capture color images while simultaneously resolving two near-infrared (NIR) probes. Our optimized EIS integrates a hexa-chromatic image sensor, a rigid endoscope optimized for NIR-color imaging, and a custom illumination fiber bundle. Our optimized EIS achieves a 60% improvement in NIR spatial resolution when compared to a leading FDA-approved endoscope. Ratio-metric imaging of two tumor-targeted probes is demonstrated in vials and animal models of breast cancer. Clinical data gathered from fluorescently tagged lung cancer samples on the operating room's back table demonstrate a high tumor-to-background ratio and consistency with the vial experiments. We investigate key engineering breakthroughs for the single-chip endoscopic system, which can capture and distinguish numerous tumor-targeting fluorophores. As the molecular imaging field shifts toward a multi-tumor targeted probe methodology, our imaging instrument can aid in assessing these concepts during surgical procedures. [ABSTRACT FROM AUTHOR]

Near-infrared fluorescence image-guided surgery is often thought of as a spectral imaging problem where the channel count is the critical parameter, but it should also be thought of as a multiscale imaging problem where the field of view and spatial resolution are similarly important. Conventional imaging systems based on division-of-focal-plane architectures suffer from a strict relationship between the channel count on one hand and the field of view and spatial resolution on the other, but bioinspired imaging systems that combine stacked photodiode image sensors and long-pass/short-pass filter arrays offer a weaker tradeoff. In this paper, we explore how the relevant changes to the image sensor and associated image processing routines affect image fidelity during image-guided surgeries for tumor removal in an animal model of breast cancer and nodal mapping in women with breast cancer. We demonstrate that a transition from a conventional imaging system to a bioinspired one, along with optimization of the image processing routines, yields improvements in multiple measures of spectral and textural rendition relevant to surgical decision-making. These results call for a critical examination of the devices and algorithms that underpin image-guided surgery to ensure that surgeons receive high-quality guidance and patients receive high-quality outcomes as these technologies enter clinical practice. [ABSTRACT FROM AUTHOR]

In this paper, we present recent work on bioinspired polarization imaging sensors and their applications in biomedicine. In particular, we focus on three different aspects of these sensors. First, we describe the electro–optical challenges in realizing a bioinspired polarization imager, and in particular, we provide a detailed description of a recent low-power complementary metal–oxide–semiconductor (CMOS) polarization imager. Second, we focus on signal processing algorithms tailored for this new class of bioinspired polarization imaging sensors, such as calibration and interpolation. Third, the emergence of these sensors has enabled rapid progress in characterizing polarization signals and environmental parameters in nature, as well as several biomedical areas, such as label-free optical neural recording, dynamic tissue strength analysis, and early diagnosis of flat cancerous lesions in a murine colorectal tumor model. We highlight results obtained from these three areas and discuss future applications for these sensors. [ABSTRACT FROM PUBLISHER]

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 am 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. [ABSTRACT FROM AUTHOR]