公开(公告)号：DE3676979D1

公开(公告)日：1991-02-21

申请号：DE3676979

申请日：1986-11-11

Applicant: IBM

Inventor： ASADA SHIGEKI ,  HASEGAWA MEGUMI

IPC: H04N1/19 ,  H04N1/047 ,  H04N1/10 ,  H04N1/193 ,  H04N1/403 ,  H04N1/028

Abstract: A reference position marker (9) on a document support table (3) is positioned within the field of view of a CCD sensor array (8) which senses an image of a document (10) placed on the table. … To distinguish the reference position marker (9) from the document image, the marker has a high reflectance surface and a round cross section to directly reflect light from a lamp (4) into the CCD sensor array (8) to cause the array to operate in a saturated range to generate a higher output signal than the highest signal expected during the document scanning operation. A control unit (30) sets a threshold of a comparator circuit (33) to a level which is exceeded by the higher output signal in the marker recognition operation and not exceeded by the highest signal generated during the document scanning operation. The threshold level is switched by the control unit after the marker (9) is detected to a level for producing bi-level signals representing the image of the document.

公开(公告)号：DE69231642D1

公开(公告)日：2001-02-22

申请号：DE69231642

申请日：1992-11-18

Applicant: IBM

Inventor： ASADA SHIGEKI ,  SOHDA MASAYUKI ,  YASUDA HIROAKI

IPC: G09G5/00 ,  G06F3/147 ,  G06T5/00 ,  G09G3/20 ,  G09G3/36 ,  H04N5/66 ,  G06F3/14

Abstract: A display system for converting N bit signals each representing 2 gray scale levels, to M bit signals representing 2 gray levels (where N is an integer larger than or equal to 2 and M is an integer satisfying N>M>/=1) comprises a register (1) for separating each of the N bit signals into higher order M bits and N-M bits. 2 tables (5,6,7,8) each store a distinctive set of PxQ modification values satisfying PxQ>/=2 . A control device (12) selects one of the tables as a function of the N-M bits. A comparator (31) detects a difference between a first set of modification values and a second set of modification values of the selected table. An exchanger (32) exchanges the first set of modification values and the second set of modification values to generate a modified table from the selected table. An adder (9) adds the M bits of one N bit signal and each of the modification values of the selected table to generate a first set of PxQ M bit signals, and adds the M bits of next N bit signal and each of the modification values of the modified table to generate a second set of PxQ M bit signals. The first and second sets of M bit signals are then supplied to a display device having 2 gray levels. This permits the addition of pel lines to the picture displayed on the LCD device to bring the aspect ratio of the LCD device into line with that of a CRT device without introducing inconsistent gray levels into the picture.