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M65762FP

QM-Coder

Renesas Electronics 

M65762FP

Specifications of Coding Functions

(1) Coding algorithm

• QM-Coder (JBIG standard arithmetic coding system)

(2) Context

a) Template model

• 2- or 3-line of 10-pixel template (see figure 1)

(Conforming to the template for JBIG minimum resolution)

Note: The coding efficiency of the 3-line template is better than that of 2-line template by several %.

b) Adaptive template (AT)

• It is possible to move up to 127 pixels on the coding line.

(AT position is indicated by MPU.)

Note: AT is available to improve the coding efficiency for dither image.

• Even in the middle of coding/decoding, the position of AT line can be changed for a line (AT move)

Note: When the position the AT pixel of is changed, the template model cannot be changed concurrently.

X XX

X X XX A

XX ?

XX X XXA

XXXX ?

Figure 1 Template (X, A) (Upper: 3 lines, Lower: 2 lines)

XXX

XXXX

A

XX ?

MAX127

XX XXX

A

XXX X?

MAX127

Figure 2 Adaptive Template (A)

(3) Typical prediction

• Agreement with the typical prediction of the minimum resolution of JBIG.

The pseudo-pixel (SLNTP) is generated by the symbol LNTP which shows whether the coding/decoding

process lines agree with the immediately preceding line. If they agree, the pseudo-pixel only is coded. This

makes it possible to shorten the time of process and rejection of the code data.

SLNTPy = ! (LNTPy ⊕ LNTPy – 1)

(Where: y indicates a lien No., y = 1 indicates that lines do not match each other, and initial value LNTP for

head line is given with y – 1 = 1)

(4) Coding data format

• The stripe data entity.

(SDE = stripe coded data with byte stuffing (PSCD) + end marker (SDNORM/SDRST))

Performs coding and decoding of one stripe (see "Appendix A.1")

In the case of multi-striped (multi-stripes), can be supported by activation for each stripe.

(5) Marker code

• Supports the SDE end marker

(During coding, the marker code previously set in the register is outputted. During decoding, the marker

code byte detected by requesting on interrupt to MPU when the maker is detected is read out of the register.)

REJ03F0235-0200 Rev.2.00 Sep 14, 2007

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