WO1999047990A1

WO1999047990A1 - Electronic privacy screen and viewer

Info

Publication number: WO1999047990A1
Application number: PCT/US1999/005682
Authority: WO
Inventors: Larry A. Nickum
Original assignee: Gateway 2000, Inc.
Priority date: 1998-03-16
Filing date: 1999-03-16
Publication date: 1999-09-23
Also published as: AU3006399A

Abstract

An electronic privacy screen and viewer determines a location in a screen image for a privacy viewer window such that a viewable portion of the screen image will be inside the window and a portion of the screen image outside the window will be obscured by a privacy mask when the screen image is displayed on a computer display. The location of the privacy viewer window is determined relative to an active position indicator, such as a mouse pointer or text cursor, and moves on the screen image in response to movement of the active position indicator. The size and shape of the viewer window is specified by the computer user.

Description

ELECTRONIC PRIVACY SCREEN AND VIEWER

Field of the Invention The present invention is related to imaging software and in particular to software that modifies screen images to preserve the privacy of the information contained therein. Background of the Invention

Computer users often find themselves in a position in which other people can read the information on their computer screens. This is especially true for laptop users who often work on their computers in public places such as airports and airplanes. Frequently, laptop computers are taken to business meetings where the user records his/her impressions of the meeting. In a friendly environment, such as the user's place of business, such visibility may be a concern if the user is working with confidential data such as employee information. However, the visibility becomes a critical liability when the user is in a public place or when in meetings with actual or potential adversaries. One physical solution is a privacy shield that fits over the computer display. However, the shields are cumbersome and are not effective when the non-privileged observer is positioned behind the user. Such privacy shields are also too large to be comfortably carried and used when traveling with a laptop. An alternate display technology using polarized screens has been proposed as a physical solution to the privacy problem, but such displays are very expensive and therefore not widely in use.

Another approach when the user operates in a shared workspace environment is disclosed in U.S. Patent Number 5,107,443 issued on April 21, 1992 to Smith et al. Smith teaches a method of creating a private region in a shared workspace which can only be viewed by specific users. This prevents non-privileged users in the shared environment from seeing the information contained within the private region. However, the private region is fully visible to an observer positioned near a privileged user. 2

Due to the lack of acceptable solutions, users have resorted to various kinds of manual "tricks" to conceal information on a computer display from prying eyes. One such scheme involves turning off the display. The observer sees only a blank screen while the user inputs his/her data so the data is secured against inadvertent disclosure. However, the user is unable to tell where sentences or paragraphs should begin or end, and frequently ends up with one long, run-on sentence that the user must take additional time to correct later. A similar manual approach requires setting the word processing display font to a symbol font so that all the text appears as gibberish. Although neither the user or the observer can read the information, at least the user can format the text as it is entered. Unfortunately, if the user has his/her fingers on the wrong keys, there is no way to know that the text entered is unintelligible. Another limitation of this scheme is that the user cannot tell where to insert new information into already entered text, with the result that sections of the document are often disjoint and must be corrected at a later time.

What is needed, then, is a low-cost privacy mechanism that preserves the confidentiality of text entered onto a computer display from others positioned near the user and that is suitable for use on both desktop and laptop computers.

Summary of the nvention An electronic privacy screen and viewer determines a location in a screen image for a privacy viewer window such that a viewable portion of the screen image will be inside the privacy viewer window and a portion of the screen image outside the privacy viewer window will be replaced with an obscuring image when the screen image is displayed on a computer display. The location of the privacy viewer window is determined relative to an active position indicator, such as a mouse pointer or text cursor, and moves within the screen image in response to movement of the active position indicator. The size and shape of the privacy viewer window is specified by the computer user.

The privacy screen and viewer is implemented in software that executes in the central processor of a computer or in a display processor on a display adapter. Alternatively, the logical processes of the invention can also be implemented in firmware on the display adapter. 3

The electronic privacy screen and viewer is portable and able to run on any type of computer under any operating or windowing system. Because the size and shape of the viewer window is configured by the user, the user controls the amount of information that can been seen by an observer. While the user knows what he/she is inputting to the computer, the observer sees only a small portion and cannot discern the full image or text. The user has complete control of formatting and can move the active position indicator to add information anywhere on the screen. Thus, the electronic privacy screen and viewer solves the problems of non-portability and expense of the current physical solutions, while providing the user with flexibility in determining the amount of privacy necessary in a given situation.

Brief Description of the Drawings Figure 1 is a screen image output by an embodiment of the invention and shows a symbol mask used as a privacy screen and an elliptical privacy viewer window.

Figure 2A-D are perspective views of a laptop computer incorporating the invention showing different sizes and shapes for the privacy viewer window with a blank mask used as the privacy screen. Figure 3 is a functional block diagram of logical processes for embodiments of the invention in a software program.

Figure 4 is a functional block diagram of alternate logical processes that create the privacy screen. Figure 5 is a functional block diagram of alternate logical processes that determines a location for the privacy viewer. Description of the Embodiments

In the following detailed description of the embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present inventions. The following detailed description is, therefore, not to be taken in a 4 limiting sense, and the scope of the present inventions is defined only by the appended claims.

The leading digit(s) of reference numbers appearing in the Figures corresponds to the Figure number, with the exception that the same reference number is used throughout to refer to an identical component which appears in multiple Figures. Signals and connections may be referred to by the same reference number or label, and the actual meaning will be clear from its use in the context of the description.

The privacy screen and viewer is described in terms of a software program that replaces a portion of a screen image displayed on a computer display with an obscuring image leaving visible a viewer window that contains a small amount of the screen image. Figure 1 shows a screen image 100 output by an embodiment of the invention. Most of a document window 102 in a word processing application 118 has been obscured by changing standard English text characters to symbols 104. The symbols 104 serve as a privacy screen which prevents an observer from discerning the meaning of the text. An elliptical window 106 surrounds a small portion of the text which remains readable. The window 106 forms a privacy viewer which contains a text cursor 114 and a mouse pointer 116. Other portions of the screen image, such as toolbars 108, scroll bars 110, and task bar 112, also remain visible. The symbols 104 effectively conceal the actual text but retain the original text formatting such as type spacing, line wraps, paragraph breaks, etc. The symbols 104 shown in Figure 1 are characters from a symbol font that correspond to the standard text characters they replace but, as will be readily apparent to one skilled in the art, a single symbol, such as an asterisk, could also be employed by changing the size of the symbol to correspond to the em spacing of the different text characters. The embodiment shown in Figure 1 thus preserves the formatting of the obscured text and simplifies the task of adding new information into existing text. Figure 2A-D are perspective views of a laptop computer 200 with an active privacy screen 202 and a viewer 204. The laptop 200 is equipped with standard components such as a computer display 206, pointing device 208, and storage 210. The storage 210 can be any computer-readable media such as a 5 floppy disk or CD-ROM that contains the privacy screen and viewer software. The storage 210 can also be a hard disk drive on which the privacy screen and viewer software is stored after acquisition through a network distribution process such as downloading from the Internet. An industry-standard central processing unit (CPU) controls the operations of the computer 200, and an industry-standard display adapter controls screen images displayed on the computer display 206. The CPU and display adapter are not shown in the figures as they are well known in the art.

Figures 2A-D show an embodiment of the invention in which the privacy screen 202 is a blank mask which obscures everything on the computer display 206 except the portion inside the viewer window 204. Figure 2A shows an elliptical privacy viewer window 204 similar to the elliptical privacy viewer window 106 (Figure 1) except that the size of the viewer window 204 is smaller so that less text is visible within the window. Figure 2B shows a large rectangular privacy viewer window 204; Figure 2C shows a small octagonal viewer window 204; and Figure 2D shows a round window 204. The applicability of different sizes and shapes for the embodiment of the privacy viewer window illustrated in Figure 1 similar to those illustrated in Figures 2A- D will be apparent to one skilled in the art. Figure 3 is a functional block diagram of logical processes for an embodiment of the invention in a software program. The logic flow is abstracted at a high level in Figure 3. The program is represented by functional modules but these modules do not necessarily correspond to distinct software modules, subroutines, subsystems, or objects. Each block can represent multiple function calls that work together to perform the specified function or can be a single program module depending on the programming language employed and the operating system under which the software executes. The links between the blocks represent procedural calls or other interprocess communications methods as will be apparent to those skilled in the art. The privacy screen and viewer program executes under operating or windowing systems such as Unix,

Macintosh, MS-DOS, Windows 3.1, Windows 95^®, or Windows NT^®, and on industry-standard workstation and/or personal computer hardware. 6

The software program incorporating the logic flow shown in Figure 3 is described in a first embodiment as logically tied to the execution of the underlying application. Alternate embodiments in which the software program is implemented in one of the underlying operating or windowing systems described above, or in a display driver for the computer display are also described.

Referring to Figure 1, in the first embodiment of the invention, a computer user begins the execution of the privacy screen and viewer software program at block 301 through one of several well-known methods, such as a pressing a "hot-key" combination or selecting a screen icon. The program retrieves default characteristics for the privacy screen and viewer from disk or random access memory and queries the user regarding any desired changes (block 303).

The user can designate the appearance of the privacy screen, such as the use of a symbol font in the application space as shown in Figure 1. For the privacy viewer, the user can specify privacy viewer window shape, and size. Because the window is dynamic in this embodiment, it will move when a text cursor moves on the display. The user also specifies an anchor point for the privacy viewer window relative to the text cursor: for example, center the window around the text cursor or tie the upper left corner to the text cursor. In Figure 1, the user has chosen an elliptical privacy viewer 106 sized to show portions of four lines of text in the document window 102 and a symbol font for the privacy screen 104.

After determining the privacy screen and viewer characteristics, in the embodiment of the invention shown in Figure 1, the program logically attaches itself to the word processing application 118 to intercept output display calls. The program captures the document text window 102 of the screen image contained in the output display call (block 305). The program determines the location of the active position indicator (text cursor 114) at block 307 and derives the location for the privacy viewer window 106 within the document window 102 based on the location of the text cursor 114 (block 309).

Once the location of the viewer window 106 is determined, the document window 102 consists of a viewable portion that lies within the privacy viewer 7 window 106 and a portion lying outside the privacy viewer window 106. The program obscures the portion of the document window 102 outside the privacy viewer window by replacing the text font with a symbol font using a privacy screen process shown as block 311. The program transmits the modified document window 102 to an underlying operating system or windowing system display procedure using a output display process shown as block 313.

In one embodiment, the output display process at block 315 substitutes the modified document window 102 in the output display call which the invention intercepted at block 305, and sends the call to the underlying system for handling. The underlying display procedure assembles the final image from the privacy viewer window, the obscured portion of the document window, and the remainder of the screen image for output on the computer display. All of the above mentioned operating systems or windowing systems provide a standard display procedure which performs the necessary operations which are well known in the art and not discussed further.

The privacy screen and viewer software determines if the user has requested termination of the program by pressing the same "hot-key" combination again, or through one of many other well known program termination mechanisms at block 315. If the user has requested termination, the program exits at block 317. If not, the program monitors the movement of the text cursor 114 (block 319) until the location of the text cursor changes. When the active position indicator moves, the software begins the logical processes of intercepting the output display call and processing the screen images at block 303. The logical processes in Figure 3 that result in the embodiment shown in

Figure 1 can also be implemented in an operating or windowing system, or in a display driver, as well as being tied to an application program. To achieve the alternate embodiments shown in Figures 2A-D, the logical processes shown in Figure 3 are implemented in an operating or windowing system or in a display driver because all the display outside the privacy viewer window is obscured, not just that portion associated with an application. An alternate embodiment in which the logical processes are implemented in an operating or windowing 8 system is described next, with an alternate embodiment implemented in a display driver described further below.

In one embodiment in an operating or windowing system, the software logic again begins by loading the default characteristics of the privacy viewer window and requesting user input at block 303. In an alternate embodiment, the program does not permit the user to change characteristics. The privacy viewer window characteristics can obscure the screen by blanking, covering it with solid color, a graphic or pattern, or executing a screen saver in the portion to be hidden. The size and shape of the privacy viewer window is also determined at block 303. In the example shown in Figure 2A, the user has chosen a blank mask as the privacy screen 202 with an elliptical privacy viewer window.

The privacy viewer window can be dynamic or static. If a static window is to be used, a fixed location on the screen is specified by the defaults or by the user. If the window is dynamic, it will move when an active position indicator moves on the display. The position indicators which can be active include a mouse pointer as well as the text cursor. The defaults or the user specify if all position indicators are to be considered in determining the active position indicator. For a dynamic window, the user also specifies an anchor point relative to the active position indicator: for example, center the window around the active position indicator or tie the upper left corner to the active position indicator. After receiving the privacy screen and viewer characteristics at block 303, the program logically attaches itself to the operating or windowing system to intercept output display calls sent to the computer display. The program captures the complete screen image in the output display call at block 305 (rather than just a document window as in the embodiment described above in conjunction with Figure 1). If the user has chosen a dynamic window, the process at block 307 determines the anchor point of the privacy viewer window based on the active position indicator. If the window is static, the process at block 307 is skipped. The program then determines a location for the privacy viewer window within the entire screen image at block 309 based on the chosen anchor point or the specified static location.

Once the location of the viewer window is determined, the complete screen image consists of a viewable portion that lies within the viewer window 9

204 and a portion to be concealed 202 that lies outside the privacy viewer window 204. The program obscures the portion of the screen image to be concealed using a privacy screen process shown as block 311. In one embodiment of the privacy screen process, the program applies the privacy screen selected by the user to the portion to be concealed 202 which is a blank mask in Figure 2A. An alternate embodiment for the privacy screen process is explained in conjunction with Figure 4 below.

The program then outputs the viewable portion 204 and the obscured portion 202 as the screen image to be displayed through a output display process shown as block 313. As described, the standard display procedure of the underlying operating or windowing system provides the necessary operations for displaying the image on the computer display.

The privacy screen and viewer software determines if the user has requested termination (block 315) and monitors the location of the active position indicator if not. When the active position indicator moves, the screen image has changed in some fashion and needs to be redrawn. The program loops back to block 303 to redraw the image. In an embodiment in which more than one position indicator can be active, block 319 determines which position indicator is the active one using logic such as described below in conjunction with Figure 5.

Because the operating and windowing systems described above provide standard system calls that the invention uses to create the privacy screen and viewer, those of skill in the art will recognize that multiple computer programs can be written that incorporate the processes described above. For example, in a Windows 95 environment, when a computer program which follows the logic shown in Figure 3 is activated by the user, the program loads the bit map chosen for use as the privacy mask into memory. The program calls the Win95 API (Application Program Interface) function " AttachThreadlnput" which captures the screen images as they are sent to the Win95 display procedure. When a screen image is captured, the program executes the API call "GetCursorPos" to determine the position of the mouse pointer or text cursor in the screen image. The program determines the absolute coordinates of the portion of the screen image which lies outside the viewer window by calculating the location 10 perimeter of the window in the screen image based on the position of pointer/cursor. The program calls the "BitBlt" display procedure API to paint the portion of the screen outside the privacy window with the selected bit map. The alternate embodiment of the privacy screen and viewer which is incorporated in a display driver is now described. Display drivers are usually software programs executing in the CPU of a computer but can designed to execute in a microprocessor of a display adapter or as part of the firmware of such a display processor. The privacy screen and viewer logic executes in the same fashion as the embodiment illustrated in Figure 3 and described above, except that, because it is part of the display driver, the logic does not need to execute a separate process 305 to capture the screen image; the image is automatically sent to the display driver by the operating system or the windowing system for processing.

Figure 4 shows an alternate embodiment of the privacy screen process shown as block 311 in Figure 3. At block 405 the portion of the screen image inside the privacy viewer window is saved to memory. The screen image including the portion inside the viewer window is replaced by the chosen privacy mask at block 407. The saved portion of the screen image is then rewritten into the image at the location of the window (block 409). This embodiment can result in faster display times depending on the image processing capabilities of the computer and operating system by lessening the number of calculations necessary to apply the mask to irregularly shaped portions of the screen outside the viewer window.

Applications, such as word processing programs, operating in a windowing environment frequently use a mouse pointer and a text cursor (or caret) with both appearing on the display simultaneously. In the embodiments shown in Figures 2A-D, the location of the privacy viewer window 204 is dependent on whether the mouse pointer or the text cursor is considered the active position indicator if the user has chosen an anchor point relative to both. In an alternate embodiment of the privacy viewer window process shown in Figure 5, movement of a mouse, or an equivalent pointing device, causes the mouse pointer to become the active position indicator. The logic in Figure 5 is incorporated into block 311 in Figure 3. Each time the screen image is 11 processed by the invention, the location of the mouse pointer is determined (block 503) and compared to a location that was saved in memory (block 505). If the mouse pointer has moved, the mouse pointer becomes the active position indicator (block 507) and the current location saved (block 509). If the mouse has not moved, the text cursor becomes the active position indicator (block 511). When the privacy viewer window follows the movement of the mouse, the user can easily scan through already-entered text to find the proper place in a document to insert new text.

Although the invention is mainly described in terms of a software program, alternate embodiments which implement the system in hardware, firmware, or a combination, will be apparent to those skilled in the art and are within the scope of the invention.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

12 What is claimed is:

1. A method of concealing a part of a screen image before it is displayed on a computer display, the method comprising the steps of: determining a location within the screen image for a privacy viewer window such that a viewable portion of the screen image is inside the window; replacing a portion of the screen image outside the privacy viewer window with an obscuring image; and transmitting the viewable and obscured portions for display en the computer display.

2. The method of claim 1 , wherein the location of the window is relative to an active position indicator located within the screen image.

3. The method of claim 2, further comprising the step of determining the active position indicator based on movement of a pointing device.

4. The method of claim 1 , wherein the portion of the screen image outside the privacy viewer window is all of the screen image except the viewable portion.

5. A method of concealing information before it is displayed on a computer display, the method comprising the steps of: determining a location within a screen image for a privacy viewer window such that a viewable portion of the screen image lies within the privacy viewer window; saving the viewable portion of the screen image to a memory; applying a privacy mask to the screen image to obscure it; writing the viewable portion from the memory into the screen image at the location of the privacy viewer window; and transmitting the viewable and obscured portions for display on the computer display. 13

6. The method of claim 5, wherein the location of the window is relative to an active position indicator located within the screen image.

7. A method of concealing information before it is displayed on a computer display comprising the steps of: determining a portion of the screen image to be concealed; replacing the portion of the screen image to be concealed with an obscuring image; and transmitting the screen image to the display.

8. The method of claim 7, wherein the portion of the screen image to be concealed is determined relative to an active position indicator located within the screen image.

9. A computer system comprising: a central processing unit; a storage coupled to the central processing unit; a display coupled to the central processing unit; an application executing in the central processing unit that creates a screen image; and privacy software executing in the central processing unit from the storage that captures the screen image created by the application and obscures a portion of the screen image before the screen image is displayed on the display.

10. The computer system of claim 9, wherein the privacy software determines the portion of the screen image to obscure based on a location of an active position indicator within the screen image.

11. A computer system comprising: a central processing unit; a storage coupled to the central processing unit; a display coupled to the central processing unit; 14 software executing in the central processing unit that creates a screen image; and a display driver that obscures a portion of the screen image before the screen image is displayed on the display.

12. The computer system of claim 11, wherein the display driver determines the portion of the screen image to obscure based on a location of an active position indicator within the screen image.

13. The computer system of claim 11, wherein the display driver is software executing in the central processor from the storage.

14. The computer system of claim 11, further comprising a display adapter processor coupled to the central processing unit and the display, and wherein the display driver is software executing in the display adapter processor from the storage.

15. A computer-readable medium having a computer program stored thereon for execution on a suitably equipped computer, the computer program comprising: a privacy process that causes the computer to modify a screen image before it is displayed on a computer display to obscure a portion of the screen image; and an output display process that causes the computer to send the modified screen image to the computer display.

16. The computer program of claim 15, wherein the privacy process comprises: a privacy viewer window process that causes the computer to determine the portion of the screen image to be obscured based on a location of an active position indicator within the screen image.

17. The computer program of claim 16, wherein the privacy viewer window process determines the location of the active position indicator based on movements of a pointing device. 15

18. The computer program of claim 15, wherein the privacy process comprises: a privacy screen process that causes the computer to replace the portion of the screen image to be obscured with an obscuring image.

19. A computer-readable medium having computer-executable instructions stored thereon to cause a suitably equipped computer to perform steps comprising: determining a location in a screen image for a privacy viewer window such that a viewable portion of the screen image is inside the window; replacing a portion of the screen image outside the privacy viewer window with an obscuring image; and transmitting the viewable and obscured portions for display on a computer display.

20. The method of claim 19, wherein the portion of the screen image outside the privacy viewer window is all of the screen image except the viewable portion.

21. A computer-readable medium having computer-executable instructions stored thereon to cause a suitably equipped computer to perform steps comprising: determining a location in a screen image for a privacy viewer window such that a viewable portion of the screen lies within the window; saving the viewable portion of the screen image to a memory; applying a privacy mask to the screen image to obscure it; writing the viewable portion from the memory into the screen image at the location of the privacy viewer window; and transmitting the viewable and obscured portions for display on a computer display.