scholarly journals Video cascade accumulation of the total solar eclipse on Svalbard 2015

2017 ◽  
Vol 6 (1) ◽  
pp. 9-14
Author(s):  
Fred Sigernes ◽  
Pål Gunnar Ellingsen ◽  
Noora Partamies ◽  
Mikko Syrjäsuo ◽  
Pål Brekke ◽  
...  
Keyword(s):  
Solar Eclipse ◽  
Solar Disk ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Total Solar Eclipse ◽  
Small Scale ◽  
Filter Technique ◽  
Video Recordings ◽  
High Dynamic ◽  
Hdr Image

Abstract. This work presents a novel image accumulation filter technique that reveals small-scale features and details from intense luminosity or high dynamic range (HDR) video recordings. It was discovered and developed from the analyses of the Norwegian Broadcasting Corporation (NRK) film of the total solar eclipse that occurred Friday 20 March 2015 in Longyearbyen (78° N, 15° E) on Svalbard, Norway. The result of the filter is fused with a HDR image of the corona and the Solar Dynamic Observatory (SDO) image of the solar disk.

scholarly journals Video cascade accumulation of the total solar eclipse on Svalbard 2015

2016 ◽  
Author(s):  
F. Sigernes ◽  
P. G. Ellingsen ◽  
N. Partamies ◽  
M. Syrjäsuo ◽  
P. Brekke ◽  
...  
Keyword(s):  
Solar Eclipse ◽  
Solar Disk ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Total Solar Eclipse ◽  
Small Scale ◽  
Video Recordings ◽  
High Dynamic ◽  
High Dynamic Range Video ◽  
Hdr Image

Abstract. This work presents a novel image accumulation filter technique that reveals small scale features and details from intense luminosity or high dynamic range video recordings. It was discovered and developed from the analyses of the Norwegian Broadcasting Corporation (NRK) film of the total solar eclipse that occurred Friday 20th of March 2015 in Longyearbyen (78° N, 15° E) on Svalbard, Norway. The result of the filter is fused with a High Dynamic Range (HDR) image of the Corona and the Solar Dynamic Observatory (SDO) image of the solar disk.

scholarly journals Serendipitous observation of a coronal mass ejection during the total solar eclipse of 14 December 2020

2021 ◽  
Vol 13 ◽  
pp. 130004
Author(s):  
Guillermo Abramson
Keyword(s):  
Coronal Mass Ejection ◽  
Solar Eclipse ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Total Solar Eclipse ◽  
High Dynamic ◽  
Mass Ejection

We report observations of the total solar eclipse of 14 December 2020, during which a coronal mass ejection was seen to propagate. A comprehensive set of photographs covering a high dynamic range of exposure enabled characterization of its dimensions. Displacement of the front can be seen during the few minutes of totality.

scholarly journals Relative sky radiance from multi-exposure all-sky camera images

2021 ◽  
Vol 14 (3) ◽  
pp. 2201-2217
Author(s):  
Juan C. Antuña-Sánchez ◽  
Roberto Román ◽  
Victoria E. Cachorro ◽  
Carlos Toledano ◽  
César López ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Quality Criteria ◽  
High Dynamic Range ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
High Dynamic ◽  
Sky Radiance ◽  
Black Level ◽  
Hdr Image

Abstract. All-sky cameras are frequently used to detect cloud cover; however, this work explores the use of these instruments for the more complex purpose of extracting relative sky radiances. An all-sky camera (SONA202-NF model) with three colour filters narrower than usual for this kind of cameras is configured to capture raw images at seven exposure times. A detailed camera characterization of the black level, readout noise, hot pixels and linear response is carried out. A methodology is proposed to obtain a linear high dynamic range (HDR) image and its uncertainty, which represents the relative sky radiance (in arbitrary units) maps at three effective wavelengths. The relative sky radiances are extracted from these maps and normalized by dividing every radiance of one channel by the sum of all radiances at this channel. Then, the normalized radiances are compared with the sky radiance measured at different sky points by a sun and sky photometer belonging to the Aerosol Robotic Network (AERONET). The camera radiances correlate with photometer ones except for scattering angles below 10∘, which is probably due to some light reflections on the fisheye lens and camera dome. Camera and photometer wavelengths are not coincident; hence, camera radiances are also compared with sky radiances simulated by a radiative transfer model at the same camera effective wavelengths. This comparison reveals an uncertainty on the normalized camera radiances of about 3.3 %, 4.3 % and 5.3 % for 467, 536 and 605 nm, respectively, if specific quality criteria are applied.

High Dynamic Range (HDR) Image Quality Assessment: A Survey

2019 ◽  
Author(s):  
Irwan Prasetya Gunawan ◽  
Ocarina Cloramidina ◽  
Salmaa Badriatu Syafa'ah ◽  
Guson Prasamuarso Kuntarto ◽  
Berkah I Santoso
Keyword(s):  
Image Quality ◽  
Quality Assessment ◽  
Image Quality Assessment ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
High Dynamic ◽  
Hdr Image

scholarly journals Relative sky radiance from multi-exposure all-sky camera images

2020 ◽  
Author(s):  
Juan C. Antuña-Sánchez ◽  
Roberto Román ◽  
Victoria E. Cachorro ◽  
Carlos Toledano ◽  
César López ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Quality Criteria ◽  
High Dynamic Range ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
High Dynamic ◽  
Sky Radiance ◽  
Black Level ◽  
Hdr Image

Abstract. All-sky cameras are frequently used to detect cloud cover; however, this work explores the use of these instruments for the more complex purpose of extracting relative sky radiances. An all-sky camera (SONA202-NF model) with three colour filters, narrower than usual for this kind of cameras, is configured to capture raw images at seven exposure times. A detailed camera characterization of the black level, readout noise, hot pixels and linear response is carried out. A methodology is proposed to obtain a linear high dynamic range (HDR) image and its uncertainty, which represents the relative sky radiance map at three effective wavelengths. The relative sky radiance (normalized by the sum of all radiances) is extracted from these maps and compared with the sky radiance measured at different sky points by a sun/sky photometer belonging to the Aerosol Robotic Network (AERONET). The camera radiances are in line with photometer ones excepting for scattering angles below 10º, which is probably due to some light reflections on the fisheye lens and camera dome. Camera and photometer wavelengths are not coincident, hence camera radiances are also compared with sky radiances simulated by a radiative transfer model at the same camera effective wavelengths. This comparison reveals an uncertainty on the normalized camera radiances about 3.3 %, 4.3 % and 5.3 % for 467, 536 and 605 nm, respectively, if specific quality criteria are applied.

scholarly journals A high dynamic range imaging algorithm: implementation and evaluation

2019 ◽  
Vol 22 (3) ◽  
pp. 293-307
Author(s):  
Vu Hong Son
Keyword(s):  
Exposure Time ◽  
Dynamic Range ◽  
Weighting Function ◽  
High Dynamic Range ◽  
Image Sensors ◽  
Current Image ◽  
High Dynamic ◽  
Low Dynamic Range ◽  
Algorithm Implementation ◽  
Hdr Image

Camera specifications have become smaller and smaller, accompanied with great strides in technology and thinner product demands, which have led to some challenges and problems. One of those problems is that the image quality is reduced at the same time. The decrement of radius lens is also a cause leading to the sensor not absorbing a sufficient amount of light, resulting in captured images which include more noise. Moreover, current image sensors cannot preserve whole dynamic range in the real world. This paper proposes a Histogram Based Exposure Time Selection (HBETS) method to automatically adjust the proper exposure time of each lens for different scenes. In order to guarantee at least two valid reference values for High Dynamic Range (HDR) image processing, we adopt the proposed weighting function that restrains random distributed noise caused by micro-lens and produces a high quality HDR image. In addition, an integrated tone mapping methodology, which keeps all details in bright and dark parts when compressing the HDR image to Low Dynamic Range (LDR) image for display on monitors, is also proposed. Eventually, we implement the entire system on Adlink MXC-6300 platform that can reach 10 fps to demonstrate the feasibility of the proposed technology.  

scholarly journals High dynamic range image compression based on visual saliency

2020 ◽  
Vol 9 ◽  
Author(s):  
Jin Wang ◽  
Shenda Li ◽  
Qing Zhu
Keyword(s):  
Image Compression ◽  
Dynamic Range ◽  
Visual Saliency ◽  
High Dynamic Range ◽  
Base Layer ◽  
Range Image ◽  
Coding Region ◽  
Compression Scheme ◽  
High Dynamic ◽  
Hdr Image

Abstract With wider luminance range than conventional low dynamic range (LDR) images, high dynamic range (HDR) images are more consistent with human visual system (HVS). Recently, JPEG committee releases a new HDR image compression standard JPEG XT. It decomposes an input HDR image into base layer and extension layer. The base layer code stream provides JPEG (ISO/IEC 10918) backward compatibility, while the extension layer code stream helps to reconstruct the original HDR image. However, this method does not make full use of HVS, causing waste of bits on imperceptible regions to human eyes. In this paper, a visual saliency-based HDR image compression scheme is proposed. The saliency map of tone mapped HDR image is first extracted, then it is used to guide the encoding of extension layer. The compression quality is adaptive to the saliency of the coding region of the image. Extensive experimental results show that our method outperforms JPEG XT profile A, B, C and other state-of-the-art methods. Moreover, our proposed method offers the JPEG compatibility at the same time.

Estimating Visual Saliency for Omnidirectional HDR Images

2021 ◽  
pp. 249-272
Author(s):  
Kenji Hara
Keyword(s):  
Coordinate System ◽  
Dynamic Range ◽  
Estimation Method ◽  
Visual Saliency ◽  
High Dynamic Range ◽  
Saliency Map ◽  
Overset Grid ◽  
High Dynamic ◽  
Low Dynamic Range ◽  
Hdr Image

A unified decomposition-and-integration-based framework is presented herein for the visual saliency estimation of omnidirectional high dynamic range (HDR) images, which allows straightforward reuse of existing saliency estimation method for typical images with narrow field-of-view and low dynamic range (LDR). First, the proposed method decomposes a given omnidirectional HDR image into multiple partially overlapping LDR images with quasi-uniform spatial resolution and without polar singularities, both spatially and in intensity using a spherical overset grid and a tone-mapping-based synthesis of imaginary multiexposure images. For each decomposed image, a standard saliency estimation method is then applied for typical images. Finally, the saliency map of each decomposed image is optimally integrated from the coordinate system of the overset grid and LDR back to the representation of the coordinate system and HDR of the original image. The proposed method is applied to actual omnidirectional HDR images and its effectiveness is demonstrated.

scholarly journals Reduced-Dimensional Capture of High-Dynamic Range Images with Compressive Sensing

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shundao Xie ◽  
Wenfang Wu ◽  
Rongjun Chen ◽  
Hong-Zhou Tan
Keyword(s):  
Compressive Sensing ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Image Sequence ◽  
Range Images ◽  
Multiple Exposure ◽  
Imaging Technology ◽  
Front End ◽  
High Dynamic ◽  
Hdr Image

The range of light illumination in real scenes is very large, and ordinary cameras can only record a small part of this range, which is far lower than the range of human eyes’ perception of light. High-dynamic range (HDR) imaging technology that has appeared in recent years can record a wider range of illumination than the perceptual range of the human eye. However, the current mainstream HDR imaging technology is to capture multiple low-dynamic range (LDR) images of the same scene with different exposures and then merge them into one HDR image, which greatly increases the amount of data captured. The advent of single-pixel cameras (compressive imaging system) has proved the feasibility of obtaining and restoring image data based on compressive sensing. Therefore, this paper proposes a method for reduced-dimensional capture of high dynamic range images with compressive sensing, which includes algorithms for front end (capturing) and back end (processing). At the front end, the K-SVD dictionary is used to compressive sensing the input multiple-exposure image sequence, thereby reducing the amount of data transmitted to the back end. At the back end, the Orthogonal Matching Pursuit (OMP) algorithm is used to reconstruct the input multiple-exposure image sequence. A low-rank PatchMatch algorithm is proposed to merge the reconstructed image sequence to obtain an HDR image. Simulation results show that, under the premise of reducing the complexity of the front-end equipment and the amount of communication data between the front end and the back end, the overall system achieves a good balance between the amount of calculation and the quality of the HDR image obtained.

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