# US 2018/0022128 A1 · Random wave mask generation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0022128 A1 - Document ID: US20180022128A1 - Status: Published application - Kind: A1 - Application number: 15/547,729 - Filed: 2015-04-17 - Published: 2018-01-25 - Earliest claimed: 2015-04-17 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: Xavier Farina Vargas; M. Isabel Borrell Bayona; Angel Martinez Barambio - Web page: https://patentgrep.com/patent/US20180022128A1 ## CPC - B41J 29/38: Drives, motors, controls or automatic cut-off devices for the entire printing mechanism - B41J 2/07: characterised by jet control (B41J2/205 takes precedence) - B41J 2/2146: {for line print heads} - G06K 15/107: {Mask selection} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract Example implementations relate to random wave mask generation. Some examples may distribute data points in a mask area based on a probability density function. The probability density function may have a maximum probability density located at a first edge and a second edge of the mask area. Some examples may also identify a wave curve that fits the data points. The wave curve may include oscillating waveforms of varying amplitudes. Some examples may also generate a random wave mask based on the wave curve. ## Claims ### Claim 1 A device for random wave mask generation comprising: a data point distribution engine to distribute data points in a mask area based on a probability density function, the probability density function having a maximum probability density located at a first edge and a second edge of the mask area; a wave curve identification engine to identify a wave curve that fits the data points, the wave curve including oscillating waveforms of varying amplitudes; and a random wave mask generation engine to generate a random wave mask based on the wave curve. ### Claim 2 (depends on 1) The device of claim 1, wherein distributing the data points in the mask area comprises: identifying a first axis range for each of the data points along a first axis of the mask area; and identifying a set of mask area coordinates for each of the data points by applying the probability density function, the probability density function being applied based on the first axis position. ### Claim 3 (depends on 2) The device of claim 2, wherein: the first axis is parallel to the first edge; and the first axis position is based on a length of the first edge and a first axis interval between each of the data points. ### Claim 4 (depends on 1) The device of claim 1, wherein identifying the wave curve that fits the data points includes fitting a smooth curve that approximates the data points to generate the oscillating waveforms. ### Claim 5 (depends on 4) The device of claim 4, wherein fitting the smooth curve comprises creating a fifth degree b-spline based on the data points. ### Claim 6 (depends on 1) The device of claim 1, wherein: the probability density function follows an inverted normal distribution having a first maximum value on the first edge, a second maximum value on the second edge, and a minimum value on a third edge of the mask area. ### Claim 7 (depends on 1) The device of claim 1, wherein: the mask area includes a plurality of cells; the wave curve divides the mask area into a first mask area and a second mask area; and generating the random wave mask based on the wave curve comprises assigning an indicator to each of the plurality of cells, the indicator being one of a first indicator and a second indicator, the first indicator being assigned to cells of the plurality of cells that correspond to the first mask area, and the second indicator being assigned to cells of the plurality of cells that correspond to the second mask area. ### Claim 8 (depends on 7) The device of claim 7, wherein: the probability density function is a first probability density function; a number of the plurality of cells adjacent to the wave curve are tapering cells; generating the random wave mask comprises determining whether to modify the assignment of the indicator of each of the tapering cells based on a second probability density function. ### Claim 9 A non-transitory machine-readable storage medium including instructions that, when executed by a processor, cause the processor to: assign a set of mask area coordinates to each of a plurality of data points, a first coordinate of the set of mask area coordinates being assigned based on a probability density function; fit a smooth curve to the data points to generate oscillating waveforms of varying amplitudes; identify tapering cells adjacent to the smooth curve; and generate a random wave mask based on the smooth curve and the identified tapering cells. ### Claim 10 (depends on 9) The non-transitory machine-readable storage medium of claim 9, wherein the tapering cells adjacent to the smooth curve comprise a number of cells adjacent to the wave curve. ### Claim 11 (depends on 9) The non-transitory machine-readable storage medium of claim 9, wherein: the random wave mask is generated by determining whether to switch the initial assignment of at least one of the tapering cells from a first set of droplet ejection elements to a second set of droplet ejection elements, the determination being based on a proximity of the at least one of the tapering cells to the smooth curve; ### Claim 12 (depends on 11) The non-transitory machine-readable storage medium of claim 11, wherein the closer the tapering cell is to the wave curve, the higher the probability of switching the initial assignment. ### Claim 13 A machine-implemented method for random wave mask generation comprising: dividing, using a processor, a mask area into a plurality of function areas; generating, using the processor, at least one probability density function, each of the at least one probability density function being associated with at least one of the function areas and having a maximum probability density located adjacent to edges of the mask area; distributing, using the processor, at least one data point in each of the function areas based on the associated probability density function; identifying, using the processor, a wave curve that connects the at least one data point in each of the function areas, the wave curve including oscillating waveforms of varying amplitudes; generating, using the processor, a random wave mask based on the wave curve; and printing content, using the processor, on a print media based on the random wave mask. ### Claim 14 (depends on 13) The computer-implemented method of claim 13, wherein the edges of the mask area are parallel. ### Claim 15 (depends on 13) The computer-implemented method of claim 13, wherein printing the content on the print media using the random wave mask includes applying the random wave mask to a plurality of droplet ejection elements.