Khairul Munadi

No-Reference PSNR Estimation for Quality Monitoring of Motion JPEG2000 Video Over Lossy Packet Networks

In this paper, we propose a no-reference (NR) method for estimating the degradation of Motion JPEG2000 (MJP2) video due to packet loss. The proposed method estimates the peak signal-to-noise ratio (PSNR) between received MJP2 frames affected by packet loss and the originally encoded frames without having information about the latter. The PSNR of a frame could be estimated in the wavelet domain, namely before the JPEG2000 decoding process, by utilizing adjacent frames that possess similar amounts of wavelet energy. Simulation results showed that the estimated PSNR is very close to the true value obtained by the full-reference calculation. Our method can be used to monitor the video quality in an IP-based transmission of MJP2, as well as for automatic judgment of error control in streaming applications, or in video broadcasting. For example, if the PSNR of a frame does not reach a predefined level, the frame will be rejected before the decoding process or it will be processed by a concealment techniques before being displayed.

Error concealment using layer structure for JPEG2000 images

A method of error concealment for JPEG2000 images is proposed in this paper. The proposed method uses the layer structure that is a feature of JPEG2000. The most significant layer is hidden in the lowest layer of the JPEG2000 bit stream, and this embedded layer is used for error concealment. The most significant layer is duplicated because JPEG2000 uses bit-plane coding. In this coding, when the upper layers are affected by errors, the coefficients of the lower layers become meaningless. A bit stream encoded using the proposed method has the same data structure as a standard JPEG2000. Therefore, it can be decoded by a standard decoder. Our simulation results demonstrated the effectiveness of the proposed method.

Efficient content-based copy detection using signs of DCT coefficient

In this paper, an efficient content-based copy detection (CBCD) method using the signs of the Discrete Cosine Transform (DCT) coefficient (S-DCT) is proposed. The S-DCTs are extracted from DC images. The proposed method uses a small-size feature, i.e., 48 bits/image, nevertheless, it resulted in neither false-negatives nor false positives. The proposed method can handle common alterations in CBCD application, such as contrast and gamma changing, noise addition, resizing, and a slight shifting. It is confirmed that the efficiency and accuracy of the proposed method are superior to those using the MPEG-7 color layout descriptor, one of the smallest image descriptors.

Error correction using data hiding technique for JPEG2000 images

A method of error correction for JPEG2000 images is proposed in this paper. The method uses the layer structure that is a feature of the JPEG2000 and an error correction code. The upper layers of the code stream are coded using an error correcting code, and the parity data are hidden in the lowest layer. The hidden data are used for error correction at the decoder. Several error correction codes with different strength are selected for the main header, packet headers, and bodies. Since the resulting code stream has the same data structure as a standard JPEG2000 code stream, it can be decoded with a general decoder. Simulation results demonstrated the effectiveness of the proposed method.

Improvement of binarization performance by applying DCT as pre-processing procedure

This paper proposes a new pre-processing approach to a sequence of binarization process, by applying the discrete cosine transform (DCT) to document image prior to binarization. This procedure can be used as a complement or alternative to denoising process used in many binarization methods. Firstly, original document images are transformed by the DCT. Then, the transformed document images are passed to standard image binarization methods, namely Otsu, Niblack, Sauvola and NICK. Secondly, original document images are directly binarized by the same methods. Then performance of the latter are compared with that of the former in terms of recall and precision. Performance evaluation are conducted by using noiseless and noisy ancient Indonesian documents with Arabic characters. It turns out that this pre-processing procedure improves binarization performance, especially for noisy documents.

Error protection for JPEG2000 encoded images and its evaluation over OFDM channel

In this paper, we propose a new error protection technique for JPEG2000 encoded images that exploits the codestream layer structure. Prior to transmission, data in the top layer are duplicated and protected by an FEC code. The data are then embedded into the bottom layer. In the receiver, a post-transmission process is applied to the codestream that extracts the embedded data for error recovery purposes. Our proposal offers several advantages: it preserves the same codestream structure as the one in the JPEG2000 part I standard, provides multilevel error protection for the top layer, and can be merged with the existing error resilience technique. Hence, the method accommodates the new requirements for wireless JPEG2000 (JPWL/JPEG2000 part 11). Simulations in an OFDM transmission environment show the effectiveness of the proposed method.

A database of printed Jawi character image

In this paper we present a printed Jawi character database for recognition research. Currently, there are Latin or Arabic character databases, while the database of Jawi character has not existed yet, neither printed nor handwritten. The database was developed to help the researcher analising and evaluating Jawi character recognition method. The characters, words and sentences were typed in a word processing application, then printed and scanned into image format. The database contains 1524 characters from four types of fonts. Besides that, the database also includes 168 printed word and sentence image.

A secure online image trading system for untrusted cloud environments.

In conventional image trading systems, images are usually stored unprotected on a server, rendering them vulnerable to untrusted server providers and malicious intruders. This paper proposes a conceptual image trading framework that enables secure storage and retrieval over Internet services. The process involves three parties: an image publisher, a server provider, and an image buyer. The aim is to facilitate secure storage and retrieval of original images for commercial transactions, while preventing untrusted server providers and unauthorized users from gaining access to true contents. The framework exploits the Discrete Cosine Transform (DCT) coefficients and the moment invariants of images. Original images are visually protected in the DCT domain, and stored on a repository server. Small representation of the original images, called thumbnails, are generated and made publicly accessible for browsing. When a buyer is interested in a thumbnail, he/she sends a query to retrieve the visually protected image. The thumbnails and protected images are matched using the DC component of the DCT coefficients and the moment invariant feature. After the matching process, the server returns the corresponding protected image to the buyer. However, the image remains visually protected unless a key is granted. Our target application is the online market, where publishers sell their stock images over the Internet using public cloud servers.

Improved Iris matching technique using reduced sized of ordinal measure of DCT coefficients

This paper presents an ongoing research on the use of ordinal measure of discrete Cosine Transform (DCT) coefficients as a feature for iris recognition. We proposed to reduce number of DCT coefficients from each 8×8 DCT block that is used to form ordinal measure. The aims were to increase matching rate while minimizing feature size. Four simulation rounds were conducted using CASIA database, each with different coefficients, namely 48, 32, 16 and 8 AC coefficients. It turned out that using as many as 8 AC coefficients from each DCT block resulted in a higher matching rate than using other number of AC coefficients of the block. The proposed method can increase averaged matching rate as much as 5% when using 8 AC coefficients. Furthermore, the proposed technique can reduce the feature size by approximately 80%.

A robust error protection technique for JPEG2000 codestream and its evaluation in CDMA environment

In this paper, a robust error protection scheme for JPEG2000 codestream is proposed. The error protection is achieved by combining the advantage of the codestream layer structure, a data hiding technique and an FEC code. At encoding stage, multiple quality layers of the codestream are protected by an FEC code with various strengths. The parity data is then hidden in the least significant layer. Prior to image decoding, error recovery is done by means of extracting the hidden data and performing the FEC decoding to the corresponding layers. The proposed method offers several benefits: it preserves the same codestream structure as the one in the JPEG2000 standard part 1, does not require additional bandwidth and can be integrated with the existing JPEG2000 error resilience tools. Hence, it accommodates one of the requirements for the upcoming wireless JPEG2000 (JPWL or JPEG2000 part 11). Simulations in a CDMA environment confirmed the proposals effectiveness.