Fiber Bundle Image Relay for Monocentric Lenses

Olivas, Stephen J.; Nikzad, Nima; Stamenov, Igor; Arianpour, Ashkan; Schuster, Glenn M.; Motamedi, Nojan; Mellette, William M.; Stack, Ronald A.; Johnson, Adam R.; Morrison, Rick L.; Agurok, Il'ya P.; Ford, Joseph E.

doi:10.1364/cosi.2014.cth1c.5

Cited by 4 publications

(9 citation statements)

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“…In the experimentally demonstrated fiber-coupled imager [12], the transmitted image of the fiber will be sampled directly by an image sensor, which is shift variant itself. Therefore in the cases where the FB's pitch is comparable with the image sensor pitch a moiré pattern will be observed [16,[22][23][24]. It has been shown that the moiré pattern can be reduced by proper image processing [16,[22][23][24].…”

Section: Quantitative Characterization Slant-edge Measurementmentioning

confidence: 99%

Analysis and characterization of high-resolution and high-aspect-ratio imaging fiber bundles

et al. 2015

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High-contrast imaging fiber bundles (FBs) are characterized and modeled for wide-angle and high-resolution imaging applications. Scanning electron microscope images of FB cross sections are taken to measure physical parameters and verify the variations of irregular fibers due to the fabrication process. Modal analysis tools are developed that include irregularities in the fiber core shapes and provide results in agreement with experimental measurements. The modeling demonstrates that the irregular fibers significantly outperform a perfectly regular "ideal" array. Using this method, FBs are designed that can provide high contrast with core pitches of only a few wavelengths of the guided light. Structural modifications of the commercially available FB can reduce the core pitch by 60% for higher resolution image relay.

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Section: Quantitative Characterization Slant-edge Measurementmentioning

confidence: 99%

Analysis and characterization of high-resolution and high-aspect-ratio imaging fiber bundles

et al. 2015

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“…With the fiber-coupled sensor in oil contact with the monocentric lens we observe local space variance of the impulse response due to the varying relative position of the quasiperiodic 2.5µm pitch fiber core relative to the 1.75µm pitch RGB color filtered sensor pixels. A detailed characterization of the space-variant impulse response of the fiber-coupled image sensor has been reported separately [11]. As we move the white spot around the field of view, it subsequently hits the different areas of the fiber bundle surface (individual cores or cladding between them), resulting in light containment that is always within a 4x4 to 3x3 pixel area (see Fig.…”

Section: Fiber-coupled Image Transfer Performancementioning

confidence: 99%

“…Maximum magnification reveals the fiber bundle structure, but the slant edge MTF measured is still excellent, with a MTF50 resolution of 110 lp/mm. The transferred image shows local defects of the fiber structure, which can be mitigated using digital image processing techniques [11] for sensor calibration. The bottom row shows the performance of the fiber-coupled imaging system.…”

Section: Fiber-coupled Image Transfer Performancementioning

confidence: 99%

“…The meniscus and 6 adjacent sensors are rigidly attached to an outer frame, while the central ball lens is mounted on a flexure that allows axial translation for focus. The sensors connect through small controller boards with USB 2.0 connection to a single host computer which acquired and displayed simultaneous images at 3 fps at full resolution, including basic image processing for sensor calibration (described in [11]). The same USB connection allows remote focus actuation via a stepper motor.…”

Section: Fiber-coupled Monocentric Lens Prototypementioning

confidence: 99%

“…12, including enlargements of selected regions across the field of view. The fiber-coupled image has been digitally processed using the global processing techniques described in [11], including compensation for fiber Moiré and local defects as well as relative illumination, along with interpolation across the vertical gaps in the sensed image field. Like most camera manufacturers, Canon compensates for sensor nonuniformities and also applies a proprietary edge-enhancement algorithm even to their raw images, similar to an unsharp mask even in RAW format, which makes the photos more visually appealing in high contrast areas, but such edge-enhancements render inaccurate MTF calculations of the Canon DSLR images.…”

Section: Fiber-coupled Monocentric Imager Vs Wide Angle Dslr Cameramentioning

confidence: 99%

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Panoramic monocentric imaging using fiber-coupled focal planes

Stamenov¹,

Arianpour²,

Olivas³

et al. 2014

Opt. Express

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Monocentric lenses provide high-resolution wide field of view imaging onto a hemispherical image surface, which can be coupled to conventional focal planes using fiber-bundle image transfer. We show the design and characterization of a 2-glass concentric F/1.0 lens, and describe integration of 5 Mpixel 1.75µm pitch back-side illuminated color CMOS sensors with 2.5µm pitch fiber bundles, then show the fiber-coupled lens compares favorably in both resolution and light collection to a 10x larger conventional F/4 wide angle photographic lens. We describe assembly of the monocentric lens and 6 adjacent sensors with focus optomechanics into an extremely compact 30Mpixel panoramic imager with a 126° "letterbox" format field of view.

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Characterizing close-focus lenses for microendoscopy

Galvez

Hong

Rocha

et al. 2023

J. Optical Microsystems

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Microendoscopes are commonly used in small lumens in the body for which a focus near to the distal tip and ability to operate in an aqueous environment are paramount for navigation and disease detection. Commercially available distal optic systems below 1 mm in diameter are severely limited, and custom micro lenses are generally very expensive. Gradient index of refraction (GRIN) singlets are available in small diameters but have limited optical performance adjustability. Three-dimensional (3D)-printed monolithic optical systems are an emerging option that may be suitable for enabling high performance, close-focus imaging. In this manuscript, we compared the optical performance of three custom distal optic systems; a custom-pitch GRIN singlet, 3D-printed monolithic doublet, and 3D-printed monolithic triplet, with a nominal working distance (WD) of 1.5, 0.5, and 0.4 mm in 0.9% saline. These short WDs are ideal for microendoscopy in collapsed or flushed lumens such as pancreatic duct or fallopian tube. The GRIN singlet had performance limited only by the fiber bundle relay over 0.9-to 1.6-mm depth of field (DOF). The 3D-printed doublet was able to achieve a comparable DOF of 0.71 mm, whereas the 3D-printed triplet suffered the most limited DOF of 0.55 mm. 3D printing enables flexible design of monolithic multielement systems with aspheric surfaces of very short WDs and relative ease of integration.

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Fiber Bundle Image Relay for Monocentric Lenses

Cited by 4 publications

References 0 publications

Analysis and characterization of high-resolution and high-aspect-ratio imaging fiber bundles

Analysis and characterization of high-resolution and high-aspect-ratio imaging fiber bundles

Panoramic monocentric imaging using fiber-coupled focal planes

Characterizing close-focus lenses for microendoscopy

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