Method for reducing noise and jitter effects in KVM systems
AssigneeDigital Multitools, Inc.
InventorBrian Carrigan
Life of this patent
Estimating the term…
Abstract
In KVM systems for comparing new video frames to reference frames to update video, a method of reducing the effects of noise comprising (i) determining the differences between the sets of pixel values for new and reference pixels to produce a difference set of difference elements for each pixel; (ii) weighting the absolute value of each difference element within the difference set (iii) summing the weighted difference elements over all of the pixels of the horizontal line of the sub-block to produce a weighted difference element sum; (iv) determining whether the weighted difference element sum exceeds a predetermined sum threshold; (v) if yes, determining that the sub-block has changed so as to require updating.
Claims23
A method of determining whether a sub-block has changed so as to require updating, for use in association with a system for updating the video of a remote computer in response to changes in the video of a target computer by comparing a reference video frame from the target computer with a new video frame, wherein updated frame sub-blocks of pixels that each have a set of pixel values associated therewith are sent to the remote computer to update it if it is determined that the sub-block has changed so as to require updating, the method comprising the steps of:
- A) for the first horizontal line of the sub-block, performing the following steps:
- (i) comparing each new video frame pixel with each corresponding reference video frame pixel by determining the differences between their corresponding sets of pixel values to produce a difference set of difference elements for each pixel;
- (ii) weighting the absolute value of each difference element within the difference set according to a predetermined weighting rule to produce a weighted difference set of weighted difference elements for the pixel, the weighting rule being configured so that the weight given to any difference element not exceeding a predetermined basic threshold is zero, and the weight given to any difference element exceeding the predetermined basic threshold is greater than zero and is non-decreasing with the size of the absolute value of the difference element;
- (iii) summing the weighted difference elements over all of the pixels of the horizontal line of the sub-block to produce a weighted difference element sum;
- (iv) determining whether the weighted difference element sum exceeds a predetermined sum threshold;
- (v) if yes, determining that the sub-block has changed so as to require updating;
- B) repeating step A for the each subsequent horizontal line of the sub-block (I) if and only if step A has not been performed for all of the horizontal lines in the sub-block;
- and (II) if it has not been determined that the sub-block has changed so as to require updating.
A method of estimating an ideal sampling timing, for use in association with a system for updating the video of a remote computer in response to changes in the video of a target computer, wherein the system uses an analog-to-digital converter to sample the incoming analog video signal from the target computer to obtain digital pixel values associated with each pixel of the incoming analog video signal, and wherein a sampling clock for controlling sampling timing is generated with reference to the H-sync signal, wherein the digital pixel values are used for comparing a reference video frame from the target computer with a new video frame, the method comprising the steps of:
- receiving a primary horizontal line of pixels of the new video frame positioned between consecutive H-sync pulses, sampled according to the sampling clock;
- creating a plurality of time-shifted lines of pixels that are equivalent to the primary line of pixels but are time-shifted relative thereto;
- performing a correlation calculation to determine, from among the primary and time-shifted lines of pixels, which line of pixels correlates most closely with a corresponding line of pixels from the reference frame;
- determining the line of pixels that correlates most closely as the new video frame line to be compared with the corresponding line of the reference frame.
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Dependencies are inferred from the claim text.