nils-herrmann/clean_scirepeval huggingface dataset:
Computational Complexity Management of a Real-Time H.264/AVC Encoder

The H.264 video coding standard supports efficient coding of video at the expense of high computational complexity. This work addresses the problem of maintaining acceptable video coding performance in a computation-constrained application scenario. A complexity management approach is proposed for an H.264 encoder running in a processor/power-constrained environment. We hypothesize that, in a power-constrained application such as mobile video telephony, good perceptual quality requires a balance between a high frame rate and acceptable image quality. Therefore, the objective of the complexity management approach is to maintain a smooth video frame rate whilst ensuring that the frame quality is not degraded unacceptably. A frame-level algorithm calculates a target coding time for each frame and drops frames when necessary to maintain acceptable image quality. A per-frame algorithm controls the coding complexity of each frame in order to achieve the target coding time. The performance of the approach is evaluated by carrying out subjective tests and comparing the managed complexity encoder with a reference encoder in a computation-constrained scenario. Subjective results show that the managed complexity encoder consistently achieves superior perceptual video quality ratings compared to the reference encoder.
A low complexity visual saliency model based on in-focus regions and centre sensitivity

A novel low-complexity visual saliency detection algorithm for detecting salient regions in images is proposed. The algorithm derives salient regions based on in-focus regions and image centre sensitivity. The performance of the algorithm in predicting human eye fixations is validated against ten state-of-the-art algorithms using a public image dataset. The results demonstrate that the proposed algorithm achieves higher prediction accuracy in saliency detection at significantly lower computational complexity compared to other algorithms.
Low-complexity skip prediction for H.264 through Lagrangian cost estimation

A complexity reduction algorithm for an H.264 encoder is proposed. Computational savings are achieved by identifying, prior to motion estimation, macroblocks (MBs) that are likely to be skipped and hence saving further computational processing of these MBs. This early prediction is made by estimating a Lagrangian rate-distortion cost function which incorporates an adaptive model for the Lagrange multiplier parameter based on local sequence statistics. Simulation results demonstrate that the algorithm can achieve computational savings of 19%-67% (depending on the source sequence) with no significant loss of rate-distortion performance.
Dynamic transform replacement in an H.264 CODEC

The current paradigm of fixed, standardized video coding algorithms limits the performance and adaptability of video codecs. Enabling dynamic adaptation of a video coding algorithm has the potential to offer improved rate distortion performance and the ability to rapidly implement changes in coding tools and techniques. We present an example of dynamic adaptation based on the H.264/AVC framework in which new transforms may be communicated to, and implemented by, a video decoder, during a coding session. Experimental results demonstrate that dynamic reconfiguration can give improved rate-distortion performance for certain combinations of video sequence and bitrate. We conclude that this is a promising avenue for further research, with significant potential benefits compared with fixed coding strategies.
3-D image coding based on affine transform

This paper is concerned with the data compression and interpolation of multi-view images. We propose the affine-based disparity compensation based on a geometric relationship. We first investigate the geometric relationship between the point in object space and its projection onto a view image. Then, we propose the disparity compensation based on the affine transform, which utilize the geometric constraints between view images. In this scheme, multi-view images are compressed into the structure and texture of the triangular patches. This scheme not only compresses the multi-view image but also synthesize the view images from any viewpoints in the viewing zone, because the geometric relationship is taken into account. Finally, we report an experiment, where 19 view images were used as the original multi-view image and the amount of data was reduced to 1/19 with an SNR of 34 dB.<<ETX>>
Multiple LED arrays acquisition for image-sensor-based I2V-VLC using block matching

The present paper proposes a novel multiple-LED-arrays acquisition for an infrastructure-to-vehicle visible light communication (I2V-VLC) using LED arrays (transmitter) and an in-vehicle high-speed image sensor (receiver). In order to achieve a robust detection of LED arrays, we employ the block matching algorithm, which is a way of finding a corresponding position between two successive frames. The proposed method divides a captured image into a number of small domains (blocks) and determines if the LED array is present or absent using the block matching. We perform I2V-VLC experiments with multiple-LED arrays and evaluate the acquisition capability of the proposed method.
Acquisition of position and direction of in-vehicle camera for HIR system

In ITS development, it is expected that infrastructure maintenance of cameras or various sensors is carried out. For a system using those infrastructure, we have proposed the HIR (human-oriented information restructuring) System. This system assists driver's visual sense by integrating and restructuring different kinds of information. This paper contributes HIR algorithm, error of data, and required accuracy towards realization of HIR System. Furthermore, we built the system to acquire position and direction of in-vehicle camera. Based on their previous study, we test the effectiveness of our developed system architecture and made experiment in the situation of turning right at the actual intersection, not georama. As a result, we can generate visual assistant images and display them on the car monitor in real-time.
Traffic sign detection in dual-focal active camera system

Traffic sign recognition systems can be applied to assist drivers and improve the traffic safety. High resolution image of traffic sign can improve the recognition result, especially for some complex traffic signs. In this paper, a dual-focal active camera system is proposed to obtain a high resolution image of traffic sign. In the system an active telephoto camera is equipped as an assistant of a wide angle camera. To make the proposed system correctly capture a high resolution image of traffic sign, the shape, color features and the relationship between continuous frames are used together in the traffic sign detection. The experiment results demonstrate that the proposed method makes the dual-focal active camera system effectively work when the system is installed on an automobile and moves on the road.
Error Correcting Scheme for Road-to-Vehicle Visible Light Communication using LED Array

In this paper, we propose an improved coding scheme for optical wireless communication systems using a LED array transmitter and a high-speed camera as the receiver on a vehicle. Previously, we have proposed a hierarchical coding scheme which allocated the data to spatial frequency components depending on the priority. In that scheme, the high-priority data can be received even if the receiver was far from the transmitter. We confirmed the advantage of the hierarchical coding scheme, but the bit error performance was not sufficient. In this paper, we divide the data into spatial frequency components, and use error correcting code for each spatial frequency components' data. Experimental evaluation demonstrates the improvement in BER performance. This improvement implies that the system range increased compared to the previous method.
Free-viewpoint image generation using different focal length camera array

The availability of multi-view images of a scene makes new and exciting applications possible, including Free-Viewpoint TV (FTV). FTV allows us to change viewpoint freely in a 3D world, where the virtual viewpoint images are synthesized by Image-Based Rendering (IBR). In this paper, we introduce a FTV depth estimation method for forward virtual viewpoints. Moreover, we introduce a view generation method by using a zoom camera in our camera setup to improve virtual viewpoint-ts' image quality. Simulation results confirm reduced error during depth estimation using our proposed method in comparison with conventional stereo matching scheme. We have demonstrated the improvement in image resolution of virtually moved forward camera using a zoom camera setup.
Overlay coding for road-to-vehicle visible light communication using LED array and high-speed camera

This paper aims to improve the visible light communication system using LED array and high-speed camera by proposing what we call “overlay coding”. “Overlay coding” is a new coding method to realize a hierarchical coding, through which a high-priority data can be received even if the receiver is far from a transmitter. Conventionally, the hierarchical coding has been realized through the wavelet transform that has a limitation of number and disposition of LEDs, and as a result it does not always match with the design of the transmitters (e.g. traffic lights, etc.) used in real life. To solve the limitation problem, we propose a more flexible way of designing the application of LEDs depending on the transmitters. In particular, overlay coding is realized through the procedures of coding and decoding. In coding, we replace one LED with a flexible number of LEDs, and the number depends on whether the data is high-priority or low-priority, then high-priority data and low-priority data are overlaid (section III-B1). In decoding, we first obtain the high-priority data, and then the low-priority data using retrieved high-priority data (section III-B2). The experimental result shows that the distance for receiving error-free data is extended from 30m to 70m in the overlay coding (section IV-B).
Real-time free viewpoint image rendering by using fast multi-pass dynamic programming

In this paper, we introduce a free viewpoint image generation method with an optimization method for a view dependent depth map. Image based rendering (IBR) can render photo-realistic images from natural images, and ray space or light field is IBR method for 3D representation. To generate a free viewpoint image from light filed data which are captured by a camera array, a disparity map on the virtual view is required. To improve the quality of the generated image, the accurate disparity map is required; however, the computational cost of the disparity map for some optimization is usually huge. For real-time rendering, we have used a disparity optimization method called multi-pass dynamic programming (MPDP), which applies the dynamic programming method to the disparity map multi-directionally. In this paper, we improve the MPDP method to speed up optimization process and add occlusion detection process. The experimental results show that fast MPDP can interpolate virtual view with high quality, and the PSNR of this synthesized image to the actual image is 29.2 dB. On the contrary, a synthesized image from belief propagation, which is one of the best optimization algorism, has 29.4 dB. In addition, the MPDP computational time is almost real-time, and that time is 51.5 ms, meanwhile belief propagation takes 397.7 ms.
Novel Demodulation Scheme Based on Blurred Images for Image-Sensor-Based Visible Light Communication

This paper proposes a novel data detection scheme based on the occurrence of blurred output images in image- sensor-based visible light communication systems. This system's receiver suffers from an inability to detect correct LED luminance values and demodulation of data because the captured image blurs owing to defocusing. The proposed method assumes that the light emitted by all LEDs that is diffused by the blur can be approximated by applying a Gaussian filter and expresses all LED luminance values as convolution equations based on this diffusion of the LED light. We estimate each LED light's condition by simultaneously solving these convolution equations and recover data according to the estimated result. To confirm the accuracy of the proposed method, we conduct computer simulations and an implementation experiment to evaluate the bit error rate performance of the proposed method.
Improved Decoding Methods of Visible Light Communication System for ITS Using LED Array and High-Speed Camera

In this paper, we consider visible light communication systems using LED array as a transmitter and high-speed camera as a receiver for Intelligent Transport System (ITS). Previously, we have proposed the hierarchical coding scheme which allocates data to spatial frequency components of the image depending on the priority. This scheme is possible to receive information of the high-priority even if communication distance is long. However, we need to distinguish multi-valued data from the received image by using a hierarchical coding. In this paper, we propose two improved decoding methods, and demonstrate to distinguish multi-valued data more correctly in the experiment.
High-speed transmission of overlay coding for road-to-vehicle visible light communication using LED array and high-speed camera

This paper aims to the improve the data rate for the visible light communication system using LED array and high-speed camera. Previously, we have proposed the decoding algorithm using inverted signals for driving situation. However, using this method the data rate become a half, because we transmit original signals and inverted signals alternately for LED array tracking. In this paper, we propose the data rate improving method for overlay coding which is coding method that overlay two data which are called as the long range data and the short range data. In the proposed method, for the long range data, we transmit original signals and inverted signals alternately. On the other hand, for the short range data, we transmit only original signals while we transmit inverted signals of long range data. We confirm that we can improve data rate as compared with the previous method.
Probabilistic reliability based view synthesis for FTV

View synthesis using depth maps is an important application in 3D image processing. In this paper, a novel method is proposed for the plausible view synthesis of Free-viewpoint TV (FTV), using two input images and their depth maps. The depth estimation based on stereo matching is known to be error-prone, leading to noticeable artifacts in the synthesized new views. To produce high-quality view synthesis, we introduce a probabilistic framework which constrains the reliability of each pixel of new view by Maximizing Likelihood (ML). The spatial adaptive reliability is provided by incorporating Gamma hyper-prior and the synthesis error approximation. Furthermore, we generate the virtual view by solving a Maximum a Posterior (MAP) problem using graph cuts. We compare the proposed method with other depth based view synthesis approaches on MPEG test sequences. The results show the outperformance of our method both at subjective artifacts reduction and objective PSNR improvement.
Detection of LED traffic light by image processing for visible light communication system

We propose a visible light road-to-vehicle communication system at intersection for ITS. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as the transmitter, and on-vehicle high-speed camera as the receiver. The LEDs in the transmitter are emitted with 500Hz and the images of those emitting LEDs are captured by a high-speed camera for conducting communication. In this communication, it is extremely necessary to find the transmitter and detect it for consecutive frames while vehicle is moving. In this paper, we introduce proposals for finding and detecting it for consecutive frames by image processing. Experimental results using appropriate images showed the effectiveness of the proposal.
Dot Matrix LCD Module for Graphic Display (64 x 320 dots)

The Graphic Dot Matrix LCD Module consisting of a super large area twisted nematic LCD of 64 x 320 dots and its driving circuit is described. This new graphic module can display not only graphic patterns but also 8 x 40 characters with 8 x 8 dot format scanned by two lines at a time method of duty 1/32 driving. The driving circuit is assembled into a compact package of 246(W) x 79(H) x 25.8(D) mm using driver LSIs, a control circuit, a temperature compensation circuit and an interface circuit, semi-compatible to a CRT display. The dot dimensions are also carefully designed to achieve optimum readability and visibility.
Motion modeling of mobile transmitter for image sensor based I2V-VLC, V2I-VLC, and V2V-VLC

Visible light communication (VLC) using light-emitting diodes (LEDs) is drawing much attention. There are two types of VLC reception devices, a photodiode and an image sensor. VLC using image sensor is called image sensor based VLC. As the receiver only uses the image sensor pixels that sense LED transmission sources and discards other pixels, including those sensing noise sources, image sensor based VLC is an attractive solution for outdoor mobile applications. However, little evidence is available for channel modeling of image sensor based VLC in mobile outdoor environments, especially for motion modeling of VLC transmitter. In this paper, we propose a motion model of VLC transmitter. In particular, we consider three cases; infrastructure-to-vehicle VLC (I2V-VLC), vehicle-to-infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). As a result, we show that the motion model of the VLC transmitter on the captured image for the three aforementioned situations (i.e., I2V-VLC, V2I-VLC, and V2V-VLC) can be expressed in the identical pinhole camera model.
Tracking an LED array transmitter for visible light communications in the driving situation

In this paper, we discuss on a decoding algorithm for visible light communication systems in the driving situation using an LED array transmitter and a high-speed camera receiver. We propose an LED array detection method using M-sequence and an LED array tracking method using inverted signals. We confirm that we can distinguish LED array candidates correctly with M-sequence. We also confirm that we can suppress the flicker of the LED and improve the data rate as compared with the previous method.
Free-Viewpoint TV

Free-viewpoint television (FTV) is an innovative visual media that enables us to view a three-dimensional (3-D) scene by freely changing our viewpoints. We proposed the concept of FTV and constructed the world???s first real-time system including the complete chain of operation from image capture to display. We also carried out the FTV on a single personal computer (PC) and a mobile player. FTV is based on the ray-space method that represents one ray in real space with one point in the ray-space. We have developed several types of ray capture systems and interfaces such as a 360° capture/ray-reproducing display. FTV is regarded as the ultimate 3DTV, since it can generate infinite number of views. Thus, FTV is the key to immersive communication. Regarding FTV as the most challenging 3-D media, the Motion Picture Experts Group (MPEG) has been conducting its international standardization activities. This article reviews FTV and its related technologies.
System design of free viewpoint video communication

We propose a free viewpoint video communication method that allows the user to change his/her viewing point and viewing direction freely. This application will be a next generation visual application in the near future. We propose suitable multiple view video coding method and communication protocol for this communication application, and demonstrate the coding efficiency of the proposed method. We also demonstrate that the developed viewer can generate the view of arbitrary viewpoint and view direction. This viewer uses the Ray-Space interpolation and extrapolation methods and generates a natural view.
FTV for 3-D Spatial Communication

Free-viewpoint TV (FTV) is cutting the frontier of audiovisual communications. FTV is an innovative media that enables us to view 3-D space by freely changing our viewpoints. It also allows us to listen at any listening point in the 3-D space. Since FTV transmits all audiovisual information of the 3-D space, it can reconstruct an audiovisual replica of the 3-D space anywhere and anytime over distance and time. For video, FTV captures a part of rays in 3-D space by using many cameras, and the other rays that are not captured are obtained by interpolating the captured rays. We constructed real-time FTV systems including the complete chain of operation from image capture to display. We also carried out FTV on a laptop computer and a mobile player. For audio, two kinds of free listening-point systems are demonstrated. MPEG regarded FTV as the most challenging 3-D media and has been conducting its international standardization activities. The first phase of FTV was multiview video coding (MVC) and the second phase of FTV is 3-D video (3DV). MVC enables the efficient coding of multiple camera views and was completed in 2009. MVC has been adopted by Blu-ray 3-D. 3DV is a standard that targets serving a variety of 3-D displays and its call for proposals was issued in March 2011.
Integration of 3D audio and 3D video for FTV

We developed an FTV system to process, and display information of 3D scene in realtime, in which users freely control their own viewpoint/listening-point position. Free listening-point can be generated by either (i) ray-space representation of sound wave field (source sound independent), or (ii) by acoustic transfer function estimation (source sound dependent) and blind separation of sources of sounds. Free viewpoint generation is based on ray-space method, which is enhanced by using multipass dynamic programming. Integration is done by either (i) ray-space representation of sound wave and images together, or (ii) integrating each camera video signal and acoustic transfer function of the same location as integrated 3DAV data. The prototype system of integrated audio-visual viewer achieves both good image and sound qualities in realtime.
3D space representation using epipolar plane depth image

We propose a novel 3D space representation for multi-view video, using epipolar plane depth images (EPDI). Multi-view video plus depth (MVD) is used as common data format for FTV(Free-viewpoint TV), which enables synthesizing virtual view images. Due to large amount of data and complexity of the multi-view video coding (MVC), compression of MVD is a challenging issue. We address this problem and propose a new representation that is constructed from MVD using rayspace. MVD is converted into image and depth ray-spaces. The proposed representation is obtained by converting each of ray-spaces into a global depth map and a texture map using EPDI. Experiments demonstrate the analysis of this representation, and its efficiency.