Emerging scientific and industrial applications of digital holography: an overview Raj Kumar, Gaurav Dwivedi Engineering Research Express, 2023 Holography is a technique to record and reconstruct three dimensional (3D) information without mandating lenses. Digital holography (DH) provides direct access to the complex amplitude of the reconstructed wavefront. This feature differentiates DH from other imaging techniques and enables it to provide quantitative information of the object under investigation. Advancements in technologies of digital image sensors, coherent sources, and computation algorithms and hardware, has paved the way of digital holographic systems for industrial applications. This work presents an overview of the scientific and industrial applications where DH can play an important role. Few of the applications of digital holographic systems in the industrial and scientific areas including microscopy, non-destructive testing, displays, environment, cloud and ocean studies are discussed.
Nondestructive Inspection and Quantification of Soldering Defects in PCB Using an Autofocusing Digital Holographic Camera Gaurav Dwivedi, Lavlesh Pensia, Viney Lohchab, Raj Kumar IEEE Transactions on Instrumentation and Measurement, 2023 The essential requirements for any digital holography-based system to get employed as an inspection device in electronic industry are portability and ability to automatically focus on the reconstruction plane. Any deviation from the exact propagation distance between the hologram plane and the reconstruction plane may result in erroneous measurement of the surface features under inspection. We report for the first time, to the best of our knowledge, the autofocus capability in a digital holography-based portable camera for full-field quantitative inspection of solder joint defects in a printed circuit board (PCB). An intensity gradient-based algorithm is developed and applied to the digital hologram to automatically locate the reconstruction plane and determine the propagation distance. For a given range of distance, the algorithm calculates the maximum value of high-frequency components in the reconstructed image, and the corresponding propagation distance is used in the reconstruction. The autofocus algorithm along with the double exposure digital holographic interferometry (DHI) is applied on the PCB under thermal loading. 2-D and 3-D deformation maps are analyzed to detect different kinds of solder joint defects, such as holes, irregular shapes, excess soldering, and bridging. The work presented in this article may further stimulate the development of digital holographic techniques for several applications in metrology and inspection in the electronics manufacturing industry.
Noise free defect detection in ceramic tableware using a portable digital holographic camera Lavlesh Pensia, Gaurav Dwivedi, Omendra Singh, Raj Kumar Applied Optics, 2022 This paper describes detection of cracks in ceramic tableware using a portable digital holographic camera working on the principle of double-exposure digital holographic interferometry. Digital image processing techniques are applied on amplitude and phase information obtained from the numerically reconstructed wavefronts of the test object to locate position of the defect. Speckles generated due to illumination of the rough surface of the ceramic cup with the coherent light source deteriorate quality of the interferometric phase. Several iterations of the averaging filter with optimized kernel size are applied on sine and cosine components of the interferometric phase to minimize the speckle noise. The effect of kernel size of the matrix used in the averaging filter on quality of the interferometric phase is analyzed by evaluating the signal-to-noise ratio. The experimentally obtained size of crack on a ceramic cup (0.08 mm) is validated by a mechanical profiler with an error of 6.6%. This study may help in improving the quality criteria of tableware items.
Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics Gaurav Dwivedi, Lavlesh Pensia, Sanjit K Debnath, Raj Kumar Journal of Optics United Kingdom, 2022 In the present work, we propose a compact digital holographic camera (DHC) with extended stochastic illumination for full-field non-destructive inspection of silicon optics fabricated in a computerized numerical control machine. The developed technique overcomes the limitation of digital holography imparted by the finite size of the active area of the recording sensor that can image a specular surface. The original aspect of this research work is to develop a system that enables reconstruction and testing of a specular surface. For this a dual diffuser configuration is incorporated in a compact DHC developed for non-destructive testing (NDT) applications. The generation of a stochastic illumination beam using the diffusers is explained by simulating the propagation of a light beam through a random phase function of the scattering medium. The stochastic optical field produced by the combination of diffusers in the DHC makes the camera suitable for NDT of the specular surface of silicon optics. The effects of the number of diffusers and their relative positions on the imaging area of the specular object are studied for development of an optimized configuration of DHC. Applicability of the proposed scheme is demonstrated through detection of defects in silicon optics using digital holographic interferometry.
A full-field optical crazimeter Raj Kumar, Tushar Varshney, Tarun Yadav, Gaurav Dwivedi, S K Barve, Omendra Singh Journal of Optics United Kingdom, 2021 Quantification of crazing in optical components made of glassy polymers is important as crazing degrades a component’s optical performance and mechanical strength. The present work describes a single-beam-based full-field optical crazimeter for imaging and quantification of crazes in transparent samples of plastic using the principles of Fourier optics. A collimated laser beam passes through the sample and acquires information about crazes present in it. A specially designed and fabricated spatial bandpass filter is used in the 4f optical information processing setup to image crazes present in the sample and reject the noise signal. Digital image processing is used to extract quantitative information about craze density from the recorded images. The proposed crazimeter may enable full-field inspection of consumer products made of various transparent plastics for the presence of crazes.
Quality evaluation of reconstructed images in digital holography to analyze the effects of source power and exposure times Optics Infobase Conference Papers, 2020
Enhanced tomographic imaging through scattering media via wavelength and exposure optimization in the SWIR digital holography G Dwivedi, V Malik, N Barak, N Chhiller, A Anand, G Sheoran Optics and Lasers in Engineering 196, 109446 , 2026 2026 Citations: 1
Comparison of numerical reconstruction of digital holograms using angular spectrum method and Fresnel diffraction method G Dwivedi, A Sharma, S Debnath, Rajkumar Journal of Optics 54 (3), 1-10 , 2025 2025 Citations: 17
Method and system for recording digital hologramsof larger objects in non-laboratory environment R Kumar, G Dwivedi, O Singh IN Patent 522,752 , 2024 2024
Multimodal optical device to study dynamics of drying process G Dwivedi, V Kumari, N Barak, A Anand, AK Sharma, G Sheoran Optics and Lasers in Engineering 169, 107726 , 2023 2023 Citations: 1
Emerging scientific and industrial applications of digital holography: an overview R Kumar, G Dwivedi Engineering Research Express 5 (3), 032005 , 2023 2023 Citations: 33
Nondestructive inspection and quantification of soldering defects in PCB using an autofocusing digital holographic camera G Dwivedi, L Pensia, V Lohchab, R Kumar IEEE Transactions on Instrumentation and Measurement 72, 1-8 , 2023 2023 Citations: 24
On-machine tool wear estimation using a portable digital holographic camera G Dwivedi, L Pensia, O Singh, R Kumar Applied Physics B 128 (4), 77 , 2022 2022 Citations: 9
Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics G Dwivedi, L Pensia, SK Debnath, R Kumar Journal of Optics 24 (4), 044001 , 2022 2022 Citations: 5
Noise free defect detection in ceramic tableware using a portable digital holographic camera L Pensia, G Dwivedi, O Singh, R Kumar Applied Optics 61 (5), B181-B189 , 2021 2021 Citations: 12
A full-field optical crazimeter R Kumar, T Varshney, T Yadav, G Dwivedi, SK Barve, O Singh Journal of Optics 23 (12), 125602 , 2021 2021 Citations: 1
Effect of displacement in object plane on reconstructed image in lens-based digital holography L Pensia, G Dwivedi, R Kumar Engineering Research Express 3 (3), 035004 , 2021 2021 Citations: 12
Crack detection in tableware items using digital holography interferometry L Pensia, G Dwivedi, O Singh, R Kumar Digital Holography and Three-Dimensional Imaging, DTu6H. 8 , 2021 2021 Citations: 1
Non-destructive inspection and quantification of defects in plywood using a portable digital holographic camera L Pensia, G Dwivedi, R Kumar Wood Science and Technology 55 (3), 873-885 , 2021 2021 Citations: 14
Portable digital holographic camera featuring enhanced field of view and reduced exposure time R Kumar, G Dwivedi, O Singh Optics and Lasers in Engineering 137, 106359 , 2021 2021 Citations: 35
Performance evaluation of a digital holographic camera under variable source power and exposure time G Dwivedi, L Pensia, SK Debnath, R Kumar Applied Optics 60 (4), A120-A130 , 2021 2021 Citations: 15
Delamination testing of polyurethane pads adhered to polishing tool using a digital holographic nondestructive testing method G Dwivedi, A Sharma, O Singh, PK Baghel, R Kumar Optical Engineering 59 (10), 102417-102417 , 2020 2020 Citations: 14
Analyzing thermal stress distribution in metallic components using digital holography G Dwivedi, R Kumar Progress in Optomechatronics: Proceedings of the 20th International … , 2020 2020 Citations: 4
Detection of crack in plywood using digital holography interferometry L Pensia, G Dwivedi, R Kumar Frontiers in Optics, JTu1A. 7 , 2020 2020
Digital holographic imaging of specular reflective objects G Dwivedi, SK Debnath, R Kumar JSAP Annual Meetings Extended Abstracts The 81st JSAP Autumn Meeting 2020 … , 2020 2020
MOST CITED SCHOLAR PUBLICATIONS
Portable digital holographic camera featuring enhanced field of view and reduced exposure time R Kumar, G Dwivedi, O Singh Optics and Lasers in Engineering 137, 106359 , 2021 2021 Citations: 35
Emerging scientific and industrial applications of digital holography: an overview R Kumar, G Dwivedi Engineering Research Express 5 (3), 032005 , 2023 2023 Citations: 33
Revisit to comparison of numerical reconstruction of digital holograms using angular spectrum method and Fresnel diffraction method G Dwivedi, SK Debnath, B Das, R Kumar Journal of Optics 49 (1), 118-126 , 2020 2020 Citations: 32
Nondestructive inspection and quantification of soldering defects in PCB using an autofocusing digital holographic camera G Dwivedi, L Pensia, V Lohchab, R Kumar IEEE Transactions on Instrumentation and Measurement 72, 1-8 , 2023 2023 Citations: 24
Comparison of numerical reconstruction of digital holograms using angular spectrum method and Fresnel diffraction method G Dwivedi, A Sharma, S Debnath, Rajkumar Journal of Optics 54 (3), 1-10 , 2025 2025 Citations: 17
Performance evaluation of a digital holographic camera under variable source power and exposure time G Dwivedi, L Pensia, SK Debnath, R Kumar Applied Optics 60 (4), A120-A130 , 2021 2021 Citations: 15
Non-destructive inspection and quantification of defects in plywood using a portable digital holographic camera L Pensia, G Dwivedi, R Kumar Wood Science and Technology 55 (3), 873-885 , 2021 2021 Citations: 14
Delamination testing of polyurethane pads adhered to polishing tool using a digital holographic nondestructive testing method G Dwivedi, A Sharma, O Singh, PK Baghel, R Kumar Optical Engineering 59 (10), 102417-102417 , 2020 2020 Citations: 14
Noise free defect detection in ceramic tableware using a portable digital holographic camera L Pensia, G Dwivedi, O Singh, R Kumar Applied Optics 61 (5), B181-B189 , 2021 2021 Citations: 12
Effect of displacement in object plane on reconstructed image in lens-based digital holography L Pensia, G Dwivedi, R Kumar Engineering Research Express 3 (3), 035004 , 2021 2021 Citations: 12
On-machine tool wear estimation using a portable digital holographic camera G Dwivedi, L Pensia, O Singh, R Kumar Applied Physics B 128 (4), 77 , 2022 2022 Citations: 9
Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics G Dwivedi, L Pensia, SK Debnath, R Kumar Journal of Optics 24 (4), 044001 , 2022 2022 Citations: 5
Analyzing thermal stress distribution in metallic components using digital holography G Dwivedi, R Kumar Progress in Optomechatronics: Proceedings of the 20th International … , 2020 2020 Citations: 4
Trapping sub-micron size particles in holographic optical tweezers G Dwivedi, A Gupta, M Shukla, S Kanaujia, S Yede, JT Andrews Journal of Physics: Conference Series 534 (1), 012059 , 2014 2014 Citations: 2
Enhanced tomographic imaging through scattering media via wavelength and exposure optimization in the SWIR digital holography G Dwivedi, V Malik, N Barak, N Chhiller, A Anand, G Sheoran Optics and Lasers in Engineering 196, 109446 , 2026 2026 Citations: 1
Multimodal optical device to study dynamics of drying process G Dwivedi, V Kumari, N Barak, A Anand, AK Sharma, G Sheoran Optics and Lasers in Engineering 169, 107726 , 2023 2023 Citations: 1
A full-field optical crazimeter R Kumar, T Varshney, T Yadav, G Dwivedi, SK Barve, O Singh Journal of Optics 23 (12), 125602 , 2021 2021 Citations: 1
Crack detection in tableware items using digital holography interferometry L Pensia, G Dwivedi, O Singh, R Kumar Digital Holography and Three-Dimensional Imaging, DTu6H. 8 , 2021 2021 Citations: 1
Method and system for recording digital hologramsof larger objects in non-laboratory environment R Kumar, G Dwivedi, O Singh IN Patent 522,752 , 2024 2024
