Erwin B. Bellers

Fast Mode Decision for H.264 Based on Rate-Distortion Cost Estimation

A fast mode decision algorithm for an H.264 encoder is proposed which reduces computation by using a statistical dependency of macroblock rate-distortion (RD) costs. The algorithm skips the motion estimation and/or intra prediction mode decision with an adaptive threshold. The simulation results show that the proposed algorithm achieves an almost 2X speedup with negligible degradation in coding efficiency.

Solving occlusion in Frame-Rate up-Conversion

Tracking motion of moving objects in a video scene by the human eye results in a stationary picture on the retina. However, if the motion is irregular, tracking can be difficult, resulting in the perception of motion blur or motion judder. This is a typical result due to the broadcast of film material. Film is captured at 24 Hz, and by picture repetition displayed at either 50 or 60 Hz. Motion judder can be eliminated at the receiver end by temporally correcting for the motion. Although this significantly improves the viewing experience, it can cause picture degradation at the boundaries of moving objects due to improper interpolation in and around occlusion areas. In this paper, we present a solution to the occlusion problem.

44.4: Motion Compensated Frame Rate Conversion for Motion Blur Reduction

Motion blur is one of the major concerns of todays LCD panels. Driving LCD panels at higher frame rates provides a means to reduce the motion blur, but to be successful also the video stream needs to be converted accordingly. This paper shows a means to reduce the motion blur by applying high frame-rate motion-compensated temporal interpolation, and illustrates the architecture that enables implementation at a consumer price level.

Understanding video pixel processing applications for flexible implementations

Media processing system-on-chips (SoCs) mainly consist of audio encoding/decoding (e.g. AC-3, MP3), video encoding/decoding (e.g. H263, MPEG-2) and video pixel processing functions (e.g. de-interlacing, noise reduction). Video pixel processing functions have very high computational demands, as they require a large amount of computations on large amount of data (note that the data are pixels of completely decoded pictures). In this paper, we focus on video pixel processing functions. Usually, these functions are implemented in dedicated hardware. However, flexibility (by means of programmability or reconfigurability) is needed to introduce the latest innovative algorithms, to allow differentiation of products, and to allow bug fixing after fabricating chips. It is impossible to fulfill the computational requirements of these functions by current programmable media processors. To achieve efficient implementations for flexible solutions, we will study, in this paper, the application characteristics of some representative video pixel processing functions. The characteristics considered are granularity of operations, amount and kind of data accesses and degree of parallelism present in these functions. We observe that from computational granularity point of view many functions can be expressed in terms of kernels e.g. Median3 (i.e. median of three values), finite impulse response (FIR) filters, table lookups (LUT) etc. that are coarser grain than ALU, Mult, MAC, etc. Regarding the kind of data accesses, we categorize these functions as regular, regular with some data rearrangement and irregular data access patterns. Furthermore, the degree of parallelism present in these functions is expressed in terms of data level parallelism (DLP) and instruction/operation level parallelism (ILP). We show with an example that these properties can be exploited to make specialized programmable processors.

Authenticating contrast and brightness adjusted images using distributed source coding and expectation maximization

Media authentication is important in content delivery via untrusted intermediaries, such as peer-to-peer (P2P) file sharing. Many differently encoded versions of a media file might exist. Our previous work applied distributed source coding not only to distinguish the legitimate diversity of encoded images from tampering but also localize the tampered regions in an image already deemed to be inauthentic. An authentication decoder was supplied with a Slepian-Wolf encoded image projection as authentication data. We extend our scheme to authenticate contrast and brightness adjusted images using an expectation maximization algorithm. Experimental results demonstrate that the proposed algorithm can distinguish legitimate encodings of authentic contrast and brightness adjusted images from illegitimately modified versions using authentication data of about 100 bytes.

Analysis and Implementation of Motion Compensated Inverse Filtering for Reducing Motion Blur on LCD panel

The concept of the motion compensated inverse filtering (MCIF) technique was proposed several years ago. The aim of the MCIF technique is to reduce the motion blur on LCD panel. In this paper, we first analyse the performance of the MCIF technique, then present a low cost implementation of the MCIF filter. The proposed implementation is flexible to handle various types of LCD panels.

A software approach to high-quality video format conversion

Video format conversion is required if the received video format mismatches the display format (spatially and/or temporally). In addition, temporal format conversion can successfully be used to eliminate movie judder (2:2 and 3:2 pull down) and generate a smooth motion portrayal. In This work, we present a novel architecture and the associated algorithms which provide high-quality video format conversion. The architecture and its representative algorithms are to a large extent based on a software approach.

Application and evaluation of texture-adaptive skin detection in TV image enhancement

This paper evaluates a case study where a previously reported texture-adaptive skin detection algorithm is applied for TV image enhancement. A color-only skin detector of an existing high-end TV chip is extended with a texture feature, enabling exclusion of skin-colored textured areas. We report the performance in terms of detection result, and in terms of image quality in a cascade of three image enhancement functions. In terms of detection score, at 80% true positive rate, the false positive rate of the texture-adaptive skin detector is 29% lower than that of the color-only skin detector, forming a clear improvement. With respect to its application in enhancement, we assess the enhancement quality by measuring the RMS error of the enhancement output compared to an optimally enhanced image based on ground-truth skin areas. When using the texture-adaptive skin detector, the enhancement RMS error is 44% lower than the RMS error when using the color-only skin detector, thereby confirming the applicability of the proposal. Subjective evaluation indicates that the proposed algorithm is better suitable for mid/high-frequency boosting applications like sharpness enhancement, and less suitable for enhancements that operate on low frequencies like color correction functions 1.

Directional and motion-compensated de-interlacing

A key technology for scan conversion algorithms is de-interlacing. Interlaced sources have been available for a long time, and as interlace is still part of the HDTV standard, even new picture material will become available in the interlaced format. A proper de-interlacing forms the basis for video processing algorithms like scaling, sharpness enhancement, and scan rate conversion. In this paper we present a new motion-compensated and directional de-interlacer.

A single-chip hybrid media processor for CRT and matrix displays-based televisions

The new generation of CRT or matrix displays-based television requires high quality video, audio and graphics processing at a lower cost. When available, such a media processing system will drive the wide spread usage of high performance television. A single chip hybrid (analog/digital) TV media processor is designed to implement high quality television at a lower cost.