Haruhisa Kato

Weighting factor determination algorithm for H.264/MPEG-4 AVC weighted prediction

H.264/MPEG-4 AVC (ISO/IEC 14496-10) adopted the weighted prediction which is particularly useful for coding the fade/dissolve transition scenes. This paper proposes a determination method of weighting factors for the weighted prediction. The simulation results show that over 30% bitrate savings can be achieved when compared with the conventional methods.

A marker-less Augmented Reality based on fast fingertip detection for smart phones

We propose a marker-less Augmented Reality (AR) application on users hand based on a fast fingertip detection technique for smart phones. A conventional hand-based marker-less AR system does not have enough accuracy and speed in human hand detection on a mobile device. This paper presents a fast hand position and posture estimation algorithm based on a fast and robust detection of non-skin regions around the hand. The proposed method realized rendering of virtual 3D models on a hand over 10 frames per second (fps) on a smart phone. Simulation results show that we can archive up to 90% complexity reduction and more accurate than the conventional method.

Vision-based robust calibration for optical see-through head-mounted displays

We propose Vision-based Robust Calibration (ViRC) method for OSTHMDs equipped with a camera. In the ViRC method, calibration parameters are decomposed into off-line parameters that remain constant relative to the positional relationship between the camera and the virtual screen, and on-line parameters related to the users eye. Calculating the off-line parameters beforehand reduces the number of unknown parameters in the on-line phase, giving robust protection against the users misalignments during calibration. In the off-line phase, the approximate position of the users eye is calculated using the PnP algorithm. In the online phase, the actual position of the users eye is estimated from the approximate one by non-linear minimization. In our experiments, we show that the ViRC method can decrease reprojection error by as much as 83% compared with the conventional method based on the DLT algorithm.

In-loop colour-space-transform coding based on integered SVD for HEVC range extensions

Inter colour-component correlation is generally very high in RGB 4:4:4 chroma format. To improve the coding performance of the high efficiency video coding (HEVC) especially for such content, we propose the in-loop colour-space-transform. The colour space is dynamically transformed into un-correlated space by employing singular value decomposition (SVD) for each block at both the encoder and decoder. Signals in transformed colour space are coded with the existing intra / inter coding framework. We utilize the simplified SVD process implemented only by integer operations for the complexity reduction. Compared with HM10.0 as an anchor method, BD-bitrate gain reached 23.8% and 23.4% for the all intra case and the random access case, respectively, while a runtime of the decoder increase 4.8-9.8%.

A Fast DV to MPEG-4 Transcoder Integrated With Resolution Conversion and Quantization

We propose a fast transcoder from digital video (DV) to MPEG-4 in the coded domain. Since DV is interlaced sequence whereas MPEG-4 (SIF) is progressive sequence and different discrete cosine transform (DCT) mode (2*4*8DCT) is used in DV, different compressed domain transcoding method from that of MPEG to MPEG conversion is required. We have exploited matrix conversion reflecting these properties and introduce approximation and integration of resolution conversion and quantization process. Simulation results of DV to MPEG-4 conversion show that the proposed method can achieve very fast conversion while maintaining high transcoding performance when compared with base-band transcoding and significant improvement over conventional method is also realized

Integrated compressed domain resolution conversion with deinterlacing for DV to MPEG-4 transcoding

In this paper we describe a fast picture size conversion with deinterlacing for digital video (DV) to MPEG-4 transcoding. By an integration of matrices operation of resolution conversion with de-interlacing and by exploiting local symmetries in the matrices, very fast conversion can be obtained. The speed up factor of the conversion is up to 1.6 and 5 for multiplication and addition, respectively, when compared with baseband domain conversion. The transcoding experiments also show that the proposed method can achieve almost the same PSNR performance as that of baseband domain conversion.

PACMAN UI: vision-based finger detection for positioning and clicking manipulations

This paper proposes an intuitive input interface that can handle various operations based on finger image recognition. It receives continuous analog input by detecting a knuckle of the users clenched fist. In contrast to the conventional wireless mouse, whose sensitivity cannot be changed dynamically, the proposed method brings not only stable positioning but also quick clicking with a small finger gesture. In order to evaluate operability, we conducted a user experiment: a time trial for target selection. The subjects completed the task with the proposed controller in 44% less time than with a conventional wireless mouse. We confirmed that the proposed method can reliably follow finger gestures.

Novel Keypoint Registration for Fast and Robust Pose Detection on Mobile Phones

We present a novel vision-based pose detection method that can be used in mobile AR services. Conventional methods are unable to meet all the requirements such as complexity, robustness and memory consumption for mobile AR services because of their trade-off relationship. In this paper, we propose a novel key point registration approach to solve the problem. Our registration method detects key point candidates and their binary descriptors from a small number of essential training images to improve robustness to changes in viewpoint. The detected features are screened by our two-stage selection method that selects only good features for pose detection. Experimental results demonstrate that our approach both improves the robustness of the conventional method by about 50% and speeds up runtime processing by about 7-10% with small memory consumption.

Fast Intra Mode Decision Method for MPEG to H.264 Transcoding

This paper proposes a fast MPEG-2 to H.264 intra frame transcoding method. It deploys a novel technology in the refering process of MPEG-2 discrete cosine transform (DCT) coefficients to determine the block size and the prediction mode of intra frame prediction for H.264. The proposed method reduces the coding complexity by approximately 60% while maintaining a peak signal to noise ratio (PSNR) compared with a typical baseband conversion.

Automatic anchorperson detection from an MPEG coded TV program

In this paper we propose an unsupervised anchorperson detection algorithm from an MPEG coded TV program recorded for many hours. In order to extract news topic presentation shots, we employed several visual features such as motion, face, caption, and clothing on an MPEG DC image domain. In the experiment, it has been shown that news topics were successfully extracted from a recorded TV program for 24 hours.