fax Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...

systems, skew is the angular deviation of the received frame from rectangularity caused by asynchronism between the scanner and the recorder. This is the same as the angle between the

scanning line A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor. On CRT screens the horizontal scan lines are visually discernible ...

, or recording line, and the

perpendicular In elementary geometry, two geometric objects are perpendicular if they intersect at a right angle (90 degrees or π/2 radians). The condition of perpendicularity may be represented graphically using the ''perpendicular symbol'', ⟂. It can ...

to the paper path. Skew is expressed numerically as the

tangent In geometry, the tangent line (or simply tangent) to a plane curve at a given point is the straight line that "just touches" the curve at that point. Leibniz defined it as the line through a pair of infinitely close points on the curve. More ...

of the deviation angle. : :''Example of +1 degree (counter-clockwise) skew in a facsimile image. The red line is perfectly horizontal.'' Skew detection and correction can be automatically applied by the receiving machine.

References

{{Use dmy dates, date=July 2019 Fax