Single-pixel imaging (SPI) uses the modulated illumination light fields and corresponding single-pixel detection values to reconstruct the image. It provides advantages in remote sensing, low light level detection and other applications. To extend the detection range, fiber laser arrays are used as light source due to their high-power output and rapid refresh rate. In this work, we designed a Fermat spiral fiber laser array with 32 sub-apertures as the illumination light source. There is no spatial periodicity in the normalized second-order intensity correlation function. Therefore, we can get better image quality of SPI compared with regular arrays, like hexagon arrays. Furthermore, we incorporatedLiNbO3modulators into the array for enhanced high-speed phase modulation. We have achieved a random illumination light field modulation frequency of at least 22 kHz.At 64×64 pixel resolution, we achieved a 100 fps frame rate and the corresponding sampling rate is 4.88%. The reconstruction algorithms are Differential Ghost Imaging (DGI) and compressed sensing (Total Variation, TV). The proposed method will greatly improve the imaging speed and illumination power of the SPI. It has great application potential in the field of remote sensing based on SPI.
An innovative single-pixel imaging (SPI) method based on untrained attention network (UAnet) is proposed. The SPI technique illuminates the target with a sequence of modulated light fields. And a single-pixel detector (SPD) is used to collect the light intensities. The image is obtained through reconstruction algorithm combining the light fields and intensities. In the novel method, we incorporate the attention gate and SPI model into the untrained Unet in order to achieve high-quality imaging at a low sampling ratio. The untrained Unet has the advantage of good generalization ability without pre-training. The attention gate can efficiently extract the main features of the target. Numerical simulations and experiments demonstrate the UAnet can obtain better image quality at a low sampling ratio (less than 10%) than the other existing algorithms. This method effectively improves the imaging quality and efficiency of SPI.
A novel single-pixel imaging (SPI) technique based on discrete orthogonal Zernike moments is proposed. In this technique, the target object is illuminated by two sets of Zernike basis patterns which satisfy the Zernike polynomials. The Zernike moments of object image are obtained by measuring the reflected light intensities with a single-pixel detector. And the object image is reconstructed by summing the product of Zernike polynomials and detected intensities iteratively. By theoretical and experimental demonstration, an image is successfully retrieved under compressive sampling. As for both gray and binary images with resolution of 128×128 pixels, the images reconstructed by Zernike patterns have better image quality compared with those reconstructed by Fourier patterns when sampling ratio is lower than 10%. This technique yields high efficiency and high imaging quality in single-pixel imaging system.
The plenoptic camera is a new camera structure which can record the intensity, color and the direction of the light by adding a microlens array in front of the image sensor. Based on some basic concepts of the focused plenoptic camera, we first analyze the imaging characteristics. Then, the design method was given. Furthermore, we establish the depth resolution model after detailed derivation. The imaging characteristics of the focused plenoptic camera with a novel structure of four types focal lengths microlens array was analyzed. The simulation results show that our designed camera has the advantages of large depth of field and high depth resolution. The method proposed in this paper can provide reference for designing plenoptic cameras for specific application scenarios.
The aerosol transmittance on the transmission route can not be ignored in atmosphere transmittance calculation. The classical mathematic models at present just calculate the vertical transmittance. MODTRAN is a good choice, but it is difficult called in users own project. In this paper, we build a model of the vertical transmittance for aerosol patterns by exponential regression analysis, and calculate aerosol transmittance on slant route by the simple mathematical relationship of vertical transmittance and horizontal transmittance. In this way, the aerosol transmittance on common route can be calculated just by the altitude of detector and slant angle of the route. We suggest the method in this paper can be easily used for the calculation in users project of real-time infrared simulation of missile-borne or airborne detector. According to the experiments, the average residuals of transmittance on slant route is less than 0.0005, while that on horizontal route is less than 0.0003.
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