This paper presents the new development of the signal waveform modulation optical disc. The signal waveform
modulation optical disc is realized through inserting a sub-pit/sub-land into an original land/pit. More storage states are
realized with changing the size and position of the sub-pits/sub-lands, which influence the corresponding readout signal
waveforms. Modulation code and its realization are key technologies for signal waveform modulation optical disc. In this
study, we employ maximum run transition code and level modulation process as the modulation code of signal waveform
modulation optical disc. A 5/6MTR (2, 10) code is designed as the first step of the proposed modulation code, and the
level modulation process are used to avoid multilevel on shortest runs. The realization process of the proposed code is
presented, and the maximum level numbers for different run-length marks are investigated with the calculated readout
This paper presents the profile measurement method for recording marks in signal waveform modulation multilevel
(SWM) read-only disc. In SWM disc, multilevel is realized with the combined varying size and position of inserted subpit/
sub-land in an original recording land/pit. The micro-patterns of the recording marks are key identifier for level of
run-lengths. In mastering process, the mark profile is shaped with timing duration variation of the power of laser beam
recorder (LBR). To form ideal SWM recording pit microstructure, atomic force microscope (AFM) is used to measure
the pit profile, which is feedback and used to adjust the writing strategy. The measured parameters including depth,
height and position, etc. 6T land and pit are selected as examples to describe the relationship between the variation of
these parameters and levels of run-lengths. The recording symbol microstructures of DVD and signal amplitude
modulation (SAM) multilevel optical disc are also measured with AFM, which are compared with the mark profile of
SWM disc. The experimental results show that the AFM measurement for SWM recording marks is an effective method.
These quantitative measurement results provide theoretical basis for SWM stamper disc manufacturing process.
Multilevel recording technology is used to improve the recording density without changing the optical and mechanical
units. A new modulation code scheme for signal waveform modulation multilevel (SWM) read-only optical disc has
been implemented. The proposed scheme is composed of run-length limited (RLL) modulation and level modulation two
steps. RLL modulation is employed to meet the requirements of channel. To acquire higher code rate, the parameter d of
RLL(d, k) is decreased to 0, which makes the presented scheme difference from other modulation codes of the optical
storage systems. Increasing the number of k also contributes to the high code rate. Decreasing d and increasing k will
respectively introduce more inter-symbol interference (ISI) and timing recovery error (TRE) to SWM optical system.
Level modulation is used to resolve these problems. The decoding rule is simple and easy for implementation. The signal
waveform of SWM disc adopted the proposed code is also described. The information bits per 400nm are 2.19, which is
46% higher than that of DVD.
A novel design of physical format coding system (PFCS) is presented based on Multi-level read-only memory disc (ML
ROM) in order to solve the problem of low efficiency and long period of disc testing during system development. The
PFCS is composed of four units, which are 'Encode', 'Add Noise', 'Decode', 'Error Rate', and 'Information'. It is
developed with MFC under the environment of VC++ 6.0, and capable to visually simulate the procedure of data
processing for ML ROM. This system can also be used for developing other optical disc storage system or similar
channel coding system.
Multilevel modulation coding is the core technology for multilevel optical storage. The technology is employed to
increase the capacity of the read-only disc with no change on original recording symbols size. With the combination of
multilevel modulation and the run-length limited modulation, short run-length with low levels can form long run-length
with high levels while it also suitable for long run-length by short run-lengths. And the DC-suppression can be controlled
by the allowance of long run-length without sacrifice effective bits. This double-modulation scheme not only can
improve coding efficiency, but also can greatly increase the recording density. In this paper, the theory of multilevel
run-length limited modulation coding is discussed. And a high rate of 6/7, five level (1,8) code scheme is proposed. This
scheme can increase the recording density compared to that in of DVD. Therefore, it is expected that this proposed
scheme could be used for the next high-density multilevel run-length limited modulation optical storage system.
Disc scratches, dusts and noise corruption et al. will cause data sequence errors including random errors and burst errors.
With the recording density of multilevel (ML) optical storage system increasing, the same length of scratches on the
surface of optical disc will bring more burst errors in ML DVD than conventional optical recording systems, e.g., digital
versatile disc (DVD) and compact disc (CD). A new interleaving scheme based on Reed-Solomon code (RS) is proposed
to solve this problem. In DVD system, the burden of the Parity of Outer-code (PO) is huge, while the Parity of Innercode
(PI) has more correcting ability than needed. The new interleaving algorithm adjusts the structure of data frame and
block and improves the interleaving depth of ECC block to reduce the burden of PO. The results of numerical
simulations are presented to verify the performance of the new interleaving algorithm compared with RSPC. The new
proposed scheme can correct maximum burst error length of the proposed code is 6912 bytes. Burst error correcting
capacity of the proposed scheme is improved up to137.4% more than that of the RSPC.
Document authentication decides whether a given document is from a specific individual or not. In this paper, we propose a new document authentication method in physical (after document printed out) domain by embedding deformation characters. When an author writers a document to a specific individual or organization, a unique error-correcting code which serves as his Personal Identification Number (PIN) is proposed and then some characters in the text line are deformed according to his PIN. By doing so, the writer's personal information is embedded in the document. When the document is received, it is first scanned and recognized by an OCR module, and then the deformed characters are detected to get the PIN, which can be used to decide the originality of the document. So the document authentication can be viewed as a kind of communication problems in which the identity of a document from a writer is being "transmitted" over a channel. The channel consists of the writer's PIN, the document, and the encoding rule. Experimental result on deformation character detection is very promising, and the availability and practicability of the proposed method is verified by a practical system.
Handwritten and machine-printed characters are recognized separately in most OCR systems due to their distinct difference. In applications where both kinds of characters are involved, it is necessary to judge a character’s handwritten/printed property before feeding it into the proper recognition engine. In this paper, a new method to discriminate between handwritten and machine-printed character is proposed. Unlike most previous works, the discrimination we carried out in this paper is totally based on single character. Five kinds of statistical features are extracted from character image, then feature selection and classification are implemented simultaneously by a learning algorithm based on AdaBoost. Experiments on large data sets have demonstrated the effectiveness of the method.