The Problem to Solve

Modern mobile devices (e.g., electronic tablets) could run applications that allow a user to capture handwritten notes using a touch sensitive surface. While handwriting on the touch sensitive surface, a typical user may rest their palm or side of their hand on the touch sensitive surface for support, causing the device to register a touch input. To avoid such inadvertent touch input, the user could elevate their hand above the touch surface when writing. Yet this workaround could be awkward and tiring to the user.

Apple's Solution: Active Writing Regions

Apple's invention relates to creating one or more regions of a touch sensitive surface to be activated individually by a user for processing touch input events. Any touch event associated with a beginning touch event that is detected in the active area is processed for display.

Any touch input event detected outside the active region that is not associated with the beginning touch event is excluded from the processing. In some implementations, a region could be visually delineated by horizontal rule lines of a virtual notebook page.

A selector/indicator could be displayed at the left or right end of the region for activating the corresponding region. Once a writing gesture is started in the active region, the writing gesture could extend outside of the active region so long as the writing gesture is made without interruption. When a region is activated by a user touching the selector/indicator, the selector/indicator could be visually augmented to indicate that its corresponding region is active. When the writing gesture is completed by the user, the writing gesture displayed in the active region could be captured and stored for use with other applications.

Apple's patent FIG. 1 illustrates a touch sensitive surface with individually selectable active regions activated when tapping the noted circles in the figure above in an iApp that's like Apple's Notes; FIG. 2 illustrates the touch sensitive surface with writing extending outside a selected active region.

Apple states that the user could make a handwritten note with a finger, stylus or other suitable writing instrument. If you've ever tried to actually use handwriting with your finger on an iPad, you know what I mean when I say the end result is vastly inaccurate, sloppy and pardon the term, retarded. Here's to hoping that if Apple is going out of their way to update their Notes app with writing capabilities, that perhaps they'll expedite their iPen accessories. I know that there are a few decent third party digital pens in the market for the iPad today, but I'd personally prefer one from Apple sooner rather than later. 

Returning to the filing, Apple states that generally, user interface element 104 could be any size or shape and located anywhere on touch sensitive surface. In the example shown, the user interface element 104 is a circle that is visually augmented (e.g., filled with color) when selected to indicate its selection and the active status of its corresponding active region 102. Visually augmenting user interface element could include, but is not limited to changing the color, shape or size of the element, animating the element, highlighting the user interface element or its background, or the like. In some implementations, the selection of region could be indicated by audio or force feedback (e.g., a vibration) in addition or in lieu of visual augmentation.

Apple further states that a settings menu or similar input mechanism could allow users to select the location of the user interface element. In some implementations, user the interface element could be a hardware button.

A final note from Apple states that when the user is finished writing in active region, the user could simply select the "Accept" button 106 to capture the handwritten note in the active region and stored in a digital image format. Only the content drawn within an active region is captured. Once captured and stored, the content could be used with other applications. Upon acceptance, the active region could be deactivated automatically. A "Clear" button 108 could be used to clear the entire active region of its contents.

Handwriting Capture Techniques

Apple's patent FIG. 1B noted above illustrates an exemplary user interface element for selecting signature retrieval options; FIG. 1C illustrates an exemplary signature capture screen; FIG. 1D illustrates the layout of FIG. 1 with the signature capture field including the signature captured from the signature capture screen of FIG. 1C; and FIG. 2B illustrates a smoothing functions for a simple curve and for a stroke that results in a point.

In a secondary invention published by the US Patent and Trademark Office today, Apple reveals "Handwriting Capture Techniques." Apple states that modern mobile devices (e.g., electronic tablets) could run applications that allow a user to capture their handwritten signature using a touch sensitive surface. For example, some delivery companies provide their delivery personnel with handheld devices that allow a customer to sign for a package by writing their signature on a touch sensitive display surface of the device using a finger or stylus. Unfortunately, if the device is capable of capturing only a few signature data points per second, and if the finger or stylus is moved quickly, there may be an insufficient number of signature data points to generate a smooth and continuous rendering of the signature.

To correct this, Apple has created a set of rules used by device's processor to render a digital image of handwriting (e.g., a handwritten signature) by connecting data points captured on a touch sensitive surface of the device with line segments or curves. A set of rules determines whether two given data points will be connected by a line segment or a curve. If a curve is used, the set of rules determine characteristics of the curve through the derivation of control points.

In some implementations, a smoothness adjustment factor could be applied to magnitudes of curve control points to reduce excessive smoothing for large distances between data points and maintain acceptable smoothing for short distances between data points. The magnitude could then be adjusted by multiplying by a constant factor which could be determined (e.g., heuristically) from the processing speed and resolution of the device upon which the curve is being rendered.

To review Apple's second patent in full, see patent application 20120256944.

Patent Credits

Today's two patent applications relating to writing on a touch sensitive surface were both filed in Q2 2011 by inventors Lyndley Crumly and David Clark.

Note that technological revelations revealed in Apple's Intellectual Property filings are not to be interpreted as rumor. Furthermore, fast-tracked fictitious rumor site timetables should be dismissed.

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