公开(公告)号：CA1299736C

公开(公告)日：1992-04-28

申请号：CA505398

申请日：1986-03-27

Applicant: IBM

Inventor： STELZENMULLER WILLIAM K

IPC: H04N7/15 ,  H03M7/46 ,  H04N1/41 ,  H04N7/26 ,  H04N7/12

Abstract: A method is disclosed for thresholding the luminance component of color picture elements (pels) prior to compression. The method is most effective when use dwith discrete color images, such as documents having areas of nominally constant color. The method uses spatial information rather than histogram information to threshold the image data. Each scan line is defined as having a series of pel runs. A pel is considered to be in a run if it's luminance is within a certain range of an average luminance based on preceding pels. Each run may end in a transition region wherein the luminance of each pel differs from the luminance of the preceding pel by more than a predetermined amount. Where a transition region is found, a local threshold is set based on the average luminance of the preceding run and of the following pel. All pels in the transition region are assigned a luminance value equal either to the average luminance of the preceding run or the actual luminance of the following pel.

公开(公告)号：FR2311450A1

公开(公告)日：1976-12-10

申请号：FR7610358

申请日：1976-04-01

Applicant: IBM

Inventor： GINDI ABRAHAM M ,  HONG JU-HI J ,  STELZENMULLER WILLIAM K

IPC: H03K5/00 ,  H03M5/12 ,  H03L7/00 ,  H04J3/06 ,  H04L5/22 ,  H04L7/00 ,  H04L7/033 ,  H04L25/40 ,  H04L25/49 ,  H04Q11/04 ,  H03K5/153

Abstract: An improved clock retiming system for pulse coded data is provided in which the clock signals are extracted from the encoded data and first and second signals of the same amplitude and frequency but of different phase are generated from the clock signals. First and second amplifiers having variable gains provide amplification for the first and second signals, respectively. The first and second amplified signals are summed to produce a third signal having a phase which is a function of the relative amplitudes of the first and second amplified signals. The original pulse encoded data is sampled with the third signal to produce the retimed data output. The original pulse encoded data is also utilized to sample the third signal. The resulting signal is filtered to provide a DC voltage feedback error signal indicative of the phase difference between the third signal and the original pulse encoded data. This feedback signal is translated into a pair of complementary signals forming inputs to the first and second amplifiers, respectively, to vary the variable gains thereof, oppositely thereby adjusting the phase of the third signal to correspond to the phase of the original pulse encoded data.

公开(公告)号：CA1200896A

公开(公告)日：1986-02-18

申请号：CA449989

申请日：1984-03-20

Applicant: IBM

Inventor： LASHER DANA A ,  STELZENMULLER WILLIAM K

IPC: H04N1/409 ,  G06T5/30 ,  H04N1/40 ,  H04N1/411 ,  H04N1/413 ,  H04N7/12

Abstract: RA982004 METHOD FOR REDUCING LINE WIDTH VARIATIONS IN BILEVEL VIDEO IMAGES For use in a teleconference system, a method of reducing line width variations, which are assumed to be the result of undersampling of the original image. Bilevel data received at a remote site is written into a pair of two-dimensional storage arrays. Data stored in the first array is examined row by row to identify different length-dependent classes of black horizontal pel runs. White or black pels in the second array are overwritten with gray pels at specific pel locations as a function of run length to reduce variations in length. The first array data is then examined on a column by column basis. Black vertical runs are classified and the second array is overwritten with gray pels using the same rules as were applied to horizontal runs. The trilevel second array data may be used to drive a display monitor or may first be subjected to further image processing.

公开(公告)号：FR2297527A1

公开(公告)日：1976-08-06

申请号：FR7537711

申请日：1975-12-05

Applicant: IBM

Inventor： STELZENMULLER WILLIAM K ,  WALKER ERNEST L

IPC: H03H9/64 ,  H04J1/00 ,  H04J11/00 ,  H04J99/00 ,  H04J4/00

Abstract: An acoustical wave filter is formed by depositing a pattern of interdigitated conductors which form a coding arrangement on a piezeoelectric crystal. Multiplex communication through the crystal is achieved by depositing input filters of differing configuration on the crystals, which separate channels by autocorrelation of a pulse code. A single output filter is provided to respond to the waves set up in the crystal by the input filters to transmit these waves to a single common conductor. Demultiplex is similarly done on a second crystal.