3D image reconstruction of terahertz computed tomography at sparse angles by total variation minimization

Wang, Dayong; Ning, Ran; Li, Gaochao; Zhao, Jie; Wang, Yunxin; Rong, Lü

doi:10.1364/ao.440847

Cited by 17 publications

(8 citation statements)

References 46 publications

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“…The quality of reconstructed images was enhanced by applying Gaussian deconvolution within the proposed LW‐GD‐PCCT method under the large wavelength condition at 0.11 THz in the THz spectrum. High‐quality images are typically reconstructed via high‐frequency systems based methods including TDS methods such as 2.5 THz 18 and 3.5 THz 21 , etc., and CW methods such as 0.279 THz, 23 2.52 THz, 24 0.2786 THz, 25 0.54 THz, 26 0.3 THz, 27 2.52 THz 28 , etc., among them the literature 26 is about CW THz PCCT, but is a proof of concept for general PCCT, not for an enhancement of image quality at larger wavelengths. In this work, the affect of Gaussian beam is modeled using Gaussian deconvolution kernels, as depicted in Equation (), which is multiplied with the pixels of reconstructed images to restore the pixels of real samples, contributing to the high cross‐SSIM to 0.9616 for Sample 1 and 0.9711 for Sample 2 at 0.11 THz, thus providing a potential enhancement for image quality under larger wavelength condition.…”

Section: Discussionmentioning

confidence: 99%

“…Currently, THz CT systems with CW sources have been extensively studied for THz imaging. [23][24][25][26] Among the existing CW THz CT systems, magnitude attenuation information were often investigated for image reconstruction, 27 and phase shift data was routinely extracted via high frequency in THz spectrum. 28 However, high-quality images are difficult to be obtained via large wavelength systems due to the low-performance (high noise power and distortions) image reconstruction occurred under large wavelength in THz spectrum.…”

Section: Introductionmentioning

confidence: 99%

“…Typically, high output power can be provided by continuous wave (CW) systems, which can precisely overcome the drawbacks of poor source power and stability existing in TDS systems. Currently, THz CT systems with CW sources have been extensively studied for THz imaging 23–26 . Among the existing CW THz CT systems, magnitude attenuation information were often investigated for image reconstruction, 27 and phase shift data was routinely extracted via high frequency in THz spectrum 28 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Large‐wavelength Gaussian deconvolution phase‐contrast computed tomography for THz continuous wave (0.11 THz)

Cha,

An,

et al. 2024

Micro & Optical Tech Letters

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This letter was to present an attempt of large‐wavelength Gaussian deconvolution phase‐contrast computed tomography (LW‐GD‐PCCT) for promotion of image quality reconstructed in low‐frequency band of terahertz (THz) spectrum at 0.11 THz. The interaction between the imaging samples and the THz Gaussian beam were formulated firstly in this paper, where the unwrapped phase was extracted specifically to portray the spatial structure distribution of the samples. Additionally, a Gaussian deconvolution was employed for the further reduction of spatial distortions. Moreover, an image reconstruction was carried out with the obtained phase sinograms based on phase‐used inverse Radon transform from the different positions on the sample. For an experimental assessment of the concept of LW‐GD‐PCCT, a single ellipsoid reflector‐based THz Gaussian beam generating system was established and samples such as polystyrene (PS) foam cuboid (Sample 1), and cylinder (Sample 2) with hollow defects (air holes and triangles) were prepared carefully in this work. To experimentally evaluate the performance of the contributing to the structural imaging over soft samples. Two‐dimensional topographies of each sample were reconstructed successfully, and the obtained cross root‐mean‐square error (cross‐RMSE), cross peak signal‐to‐noise ratio (cross‐PSNR), and cross structural similarity (cross‐SSIM) were 151.6451, 26.3225, and 0.9616 for Sample 1 with a high dose of 180 projections respectively, as well as 30.3242, 33.3129, and 0.9711 for Sample 2 with a low dose of 36 projections, respectively. The obtained imaging indicators of this work showed a superiority of imaging quality over those of recent works. Furthermore, the investigation of the bearing capacity has shown promise in enhancing image quality even in low‐dose conditions. The presented results suggest that the unwrapped phase combining with Gaussian deconvolution in low‐frequency band of THz imaging would be useful to improve the reconstructed image quality, potential to highly feasible non‐destructive testing of polymer foam via large wavelength.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Large‐wavelength Gaussian deconvolution phase‐contrast computed tomography for THz continuous wave (0.11 THz)

Cha,

An,

et al. 2024

Micro & Optical Tech Letters

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“…[ 32 ] In this mechanism, computer vision techniques provide various 3D reconstructed models, including outer‐shape restorations, [ 33 ] surface observations, [ 34 ] and narrowband THz computer tomography. [ 35 ] Nonetheless, efforts to demonstrate the associated computer vision‐driven non‐destructive broadband (MMW–IR) multiple‐wavelength imaging and the subsequent inner structure reconstructions of composite multi‐layer 3D objects are insufficient, yet. In other words, demonstrating the above concept is indispensable for developing CNT film imagers and PTE monitoring as practical industrial non‐destructive inspection techniques.…”

Section: Introductionmentioning

confidence: 99%

Simple Non‐Destructive and 3D Multi‐Layer Visual Hull Reconstruction with an Ultrabroadband Carbon Nanotubes Photo‐Imager

Li,

Kinoshita,

Shikichi

et al. 2023

Advanced Optical Materials

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While millimeter‐wave (MMW)–infrared (IR) broad photo‐imaging exhibits significant potential as an inspection technique, photo‐thermoelectric (PTE) detector operations employing carbon nanotubes (CNTs) are highly suitable because of their efficient absorption characteristics in the above bands. Such an imaging device design and the associated material coordination allow the aggregation of multiple wavelength‐specific optical information for the constituent identification of target objects in a non‐destructive manner with high sensitivity. On the other side, computer vision techniques facilitate 3D structure reconstruction as approaches from inspection methodologies, in addition to the aforementioned imaging device design. Although non‐destructive inspections require collectively satisfying both constituent identification and structural reconstruction, investigations combining MMW–IR broad photo imaging and computer vision monitoring are still insufficient. This work demonstrates computer vision‐driven simple 3D composite multi‐layer reconstructions via non‐destructive broadband multiple‐wavelength monitoring with the CNT film PTE imager. Visual hull evaluation, which is one of the representative computer vision techniques, converts 2D transmissive PTE images with different viewpoints into 3D reconstruction models. The subsequential graphical superposition of these wavelength‐specific models results in non‐destructive entire reconstructions of 3D composite multi‐layer target objects. Therefore, the present computer vision‐driven PTE broadband 3D reconstruction bridges the gap between methodologies and device design strategies toward non‐destructive inspection applications.

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“…(iii) The components for terahertz imaging (such as lenses) are poorly developed or unavailable. Wang et al [ 19 ] carried out 3D terahertz transmission tomography on homogeneous objects using a THz source with a frequency of 278.6 GHz (

) and a mono-spectral point sensor (Golay cell sensor with a diameter of 6 mm). The time required for an object of size

is equal to 9 h. Balacey et al [ 20 ] developed a 3D point-by-point THz imaging system in transmission using a 287 GHz frequency source and a spectrally limited point sensor (220–330 GHz diode).…”

Section: Introductionmentioning

confidence: 99%

Terahertz Constant Velocity Flying Spot for 3D Tomographic Imaging

et al. 2023

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This work reports on a terahertz tomography technique using constant velocity flying spot scanning as illumination. This technique is essentially based on the combination of a hyperspectral thermoconverter and an infrared camera used as a sensor, a source of terahertz radiation held on a translation scanner, and a vial of hydroalcoholic gel used as a sample and mounted on a rotating stage for the measurement of its absorbance at several angular positions. From the projections made in 2.5 h and expressed in terms of sinograms, the 3D volume of the absorption coefficient of the vial is reconstructed by a back-projection method based on the inverse Radon transform. This result confirms that this technique is usable on samples of complex and nonaxisymmetric shapes; moreover, it allows 3D qualitative chemical information with a possible phase separation in the terahertz spectral range to be obtained in heterogeneous and complex semitransparent media.

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3D image reconstruction of terahertz computed tomography at sparse angles by total variation minimization

Cited by 17 publications

References 46 publications

Large‐wavelength Gaussian deconvolution phase‐contrast computed tomography for THz continuous wave (0.11 THz)

Large‐wavelength Gaussian deconvolution phase‐contrast computed tomography for THz continuous wave (0.11 THz)

Simple Non‐Destructive and 3D Multi‐Layer Visual Hull Reconstruction with an Ultrabroadband Carbon Nanotubes Photo‐Imager

Terahertz Constant Velocity Flying Spot for 3D Tomographic Imaging

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