Innovative 3D Depth Map Generation From A Holoscopic 3D Image Based on Graph Cut Technique

Holoscopic 3D imaging is a promising technique for capturing full-colour spatial 3D images using a single aperture holoscopic 3D camera. It mimics fly’s eye technique with a microlens array, which views the scene at a slightly different angle to its adjacent lens that records three-dimensional information onto a two-dimensional surface. This paper proposes a method of depth map generation from a holoscopic 3D image based on graph cut technique. The principal objective of this study is to estimate the depth information presented in a holoscopic 3D image with high precision. As such, depth map extraction is measured from a single still holoscopic 3D image which consists of multiple viewpoint images. The viewpoints are extracted and utilised for disparity calculation via disparity space image technique and pixels displacement is measured with sub-pixel accuracy to overcome the issue of the narrow baseline between the viewpoint images for stereo matching. In addition, cost aggregation is used to correlate the matching costs within a particular neighbouring region using sum of absolute difference (SAD) combined with gradient-based metric and “winner takes all” algorithm is employed to select the minimum elements in the array as optimal disparity value. Finally, the optimal depth map is obtained using graph cut technique. The proposed method extends the utilisation of holoscopic 3D imaging system and enables the expansion of the technology for various applications of autonomous robotics, medical, inspection, AR/VR, security and entertainment where 3D depth sensing and measurement are a concern

3D Holoscopic Imaging for Cultural Heritage Digitalisation

The growing interest in archaeology has enabled the discovery of an immense number of cultural heritage assets and historical sites. Hence, preservation of CH through digitalisation is becoming a primordial requirement for many countries as a part of national cultural programs. However, CH digitalisation is still posing serious challenges such as cost and time-consumption. In this manuscript, 3D holoscopic (H3D) technology is applied to capture small sized CH assets. The H3D camera utilises micro lens array within a single aperture lens and typical 2D sensor to acquire 3D information. This technology allows 3D autostereoscopic visualisation with full motion parallax if convenient Microlens Array (MLA)is used on the display side. Experimental works have shown easiness and simplicity of H3D acquisition compared to existing technologies. In fact, H3D capture process took an equal time of shooting a standard 2D image. These advantages qualify H3D technology to be cost effective and time-saving technology for cultural heritage 3D digitisation

An error resilience method for depth in stereoscopic 3D video

Error resilience stereoscopic 3D video can ensure robust 3D video communication especially in high error rate wireless channel. In this paper, an error resilience method is proposed for the depth data of the stereoscopic 3D video using data partitioning. Although data partitioning method is available for 2D video, its extension to depth information has not been investigated in the context of stereoscopic 3D video. Simulation results show that the depth data is less sensitive to error and should be partitioned towards the end of the data partitions block. The partitioned depth data is then applied to an error resilience method namely multiple description coding (MDC) to code the 2D video and the depth information. Simulation results show improved performance using the proposed depth partitioning on MDC compared to the original MDC in an error prone environment

Error control strategies in block-transform video coders for multimedia communications.

The aim of this research is to enhance the quality of service in video applications when they are operating over error prone environments. With high compression ratio and low complexity block transform video coders, such as ITU-T H.263 standard algorithm for very low bit rate video coding, compressed video streams can be used for multimedia services. However, when transmitting compressed video streams over channels with degraded conditions, several problems arise and undermine the video decoder from correctly reconstructing the video signal. This thesis presents several techniques employed to enhance the quality of service of a video communication application under erroneous conditions. First, block transform methods for video coding are examined, and their strengths and weaknesses are assessed in terms of performance and error robustness. Packetised video signals are considered and two different techniques are implemented for packet video networks to improve the quality of service on one hand and help resolve the state of congestion that might occur on any video communication medium on the other hand. Additionally, zero redundancy error concealment techniques are considered and applied on the block based video decoder to improve the quality of the reconstructed video signal without any redundancy added on the video bitstream. Then, the aspects of error resilience issues in block transfom video coders are discussed. Based on the different categories of errors encountered in coded video streams, several novel techniques are implemented to render the video coder more immune to channel deterioration. Some of these techniques are combined to form an error resilience algorithm that is implemented on H.263 to enhance its performance over error prone environments such as mobile radio links. In parallel with the development process of the MPEG-4 video coder, we apply the two-way decoding with reversible codewords on the H.263 standard. Results are shown throughout the thesis to evidence the effectiveness of the proposed techniques and illustrate the improvement on the quality of service on both the objective and subjective scales. We conclude with thoughts for future expansion of error control strategies in block based video coding for mobile multimedia services over the foreseen universal mobile telecommunication systems (UMTS) network

WAVE OPTICS ANALYSIS OF CAMERA IMAGE FORMATION WITH RESPECT TO RECTANGULAR APERTURE

ABSTRACT KEYWORDS Electromagnetic spectrum, Camera aperture dimension, 2D and 3D sensor field distribution, Modulation transfer function