Field Photometer with Nine-Element Filter Wheel

Frentress, Z.; Young, L.; Edwards, H. D.

doi:10.1364/ao.3.000303

Cited by 5 publications

(3 citation statements)

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“…The color filter array (CFA) or multispectral filter array [ 13 ] plays an essential role in acquiring the color information or spectral information in the RGB camera and multispectral camera. One of the early and intuitive studies of the optical filter is filter-wheel camera [ 14 ]. A series of special optical filters are installed in the rotating filter wheel, where each optical filter can be placed in the optical path of a monochrome camera by rotating the filter wheel.…”

Section: Related Workmentioning

confidence: 99%

Color-Ratio Maps Enhanced Optical Filter Design and Its Application in Green Pepper Segmentation

Kurihara

Shu

2021

Sensors

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There is a growing demand for developing image sensor systems to aid fruit and vegetable harvesting, and crop growth prediction in precision agriculture. In this paper, we present an end-to-end optimization approach for the simultaneous design of optical filters and green pepper segmentation neural networks. Our optimization method modeled the optical filter as one learnable neural network layer and attached it to the subsequent camera spectral response (CSR) layer and segmentation neural network for green pepper segmentation. We used not only the standard red–green–blue output from the CSR layer but also the color-ratio maps as additional cues in the visible wavelength and to augment the feature maps as the input for segmentation. We evaluated how well our proposed color-ratio maps enhanced optical filter design methods in our collected dataset. We find that our proposed method can yield a better performance than both an optical filter RGB system without color-ratio maps and a raw RGB camera (without an optical filter) system. The proposed learning-based framework can potentially build better image sensor systems for green pepper segmentation.

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Section: Related Workmentioning

confidence: 99%

Color-Ratio Maps Enhanced Optical Filter Design and Its Application in Green Pepper Segmentation

Kurihara

Shu

2021

Sensors

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“…A common and illustrative instance is the filter wheel (see Figure 3a ), where a series of desired optical filters are installed [ 8 ]. When integrated with a monochromatic camera and typically inserted in the optical path, such a filter wheel may work in a synchronized way with the camera, so that one exposure corresponds to a certain type of filter, which yields a given spectral region or band.…”

Section: State-of-the-artmentioning

confidence: 99%

Multispectral Filter Arrays: Recent Advances and Practical Implementation

Lapray

Wang

Thomas

et al. 2014

Sensors

216

159

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Thanks to some technical progress in interferencefilter design based on different technologies, we can finally successfully implement the concept of multispectral filter array-based sensors. This article provides the relevant state-of-the-art for multispectral imaging systems and presents the characteristics of the elements of our multispectral sensor as a case study. The spectral characteristics are based on two different spatial arrangements that distribute eight different bandpass filters in the visible and near-infrared area of the spectrum. We demonstrate that the system is viable and evaluate its performance through sensor spectral simulation.

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“…Although this method provides the highest resolution, the sensing devices have significant size and weight disadvantages [6]. Most of the spectral images acquisition methods are related to scanning operations where multiple exposures are used causing motion artifacts [7].…”

Section: Introductionmentioning

confidence: 99%