Patent Application
20090322655
The present invention generally relates to displays, and more particularly relates to systems and methods for modifying an intensity of a cathode ray tube stroke signal provided to a digital display.
Conversion of analog stroke deflection-based video for a cathode ray tube (CRT) display into a digitized format for display creates differences in appearance. The CRT-based display utilizes a combination of video intensity and deflection rate or electron beam velocity to provide differences in presentation intensity of displayed data. Specifically, the faster the electron beam in the CRT display is deflected or moving, the lower the luminance of the line being drawn and vice versa. Conventional digitized stroke display conversions do not take this fact into consideration when providing the stroke signal to the digital display. As a result, some data being displayed on the digital display may include a higher or lower level of luminance than intended for a CRT display.
Accordingly, it is desirable to systems and methods for modifying an intensity of a CRT stroke signal intended for an electron beam provided to a CRT display, when applied to a digital display, to control the level of luminance of the data being displayed. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
Various embodiments provide an apparatus for modifying an intensity of a cathode ray tube stroke signal provided to a digital display displaying a stroke image. One apparatus comprises a velocity circuit configured to be coupled to the digital display and configured to determine a vector velocity of the stroke image. The apparatus further comprises an encoder circuit coupled to the velocity module and configured to modify the intensity of the stroke signal based on the vector velocity.
Systems for modifying an intensity of a cathode ray tube stroke signal provided to a digital display displaying a stroke image are also provided. One system comprises a first deflection input from a first plane, a second deflection input from a second plane, a multiplexer (MUX) configured to output the stroke signal, and a velocity intensity module (VIM) coupled to the first deflection input, the second deflection input, and the MUX. The VIM is configured to receive the stoke signal, determine a vector velocity of the stroke image based on the first and second deflection inputs, and modify the intensity of the stroke signal based on the vector velocity.
Also provided are methods for modifying an intensity of a cathode ray tube stroke signal provided to a digital display displaying a stroke image. One method comprises the steps of receiving a first deflection input and a second deflection input for the stroke image, determining a vector velocity of the stroke image based on the first and second deflection inputs, and modifying the intensity of the stroke signal based on the vector velocity.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
Various embodiments of the invention provide systems and methods for modifying an intensity of a cathode ray tube (CRT) stroke signal provided to a digital display displaying a stroke image. Specifically, the systems and methods modify the intensity of the CRT stroke signal based on the vector velocity of the stroke image.
Turning now to the figures,
As discussed above, the luminance of the line being drawn in a CRT display is dependent on the vector velocity at which the electron beam is being deflected (or moving) and the value of the video intensity input. That is, the faster the electron beam is deflected, the lower the luminance of the line that is being drawn on the CRT display, and vice versa. The vector velocity of the electron beam can be determined using the change in position (i.e., the X-axis deflection and the Y-axis deflection) of the electron beam over time. With this in mind, the present invention uses signals for displaying a stroke image on digital display 110 to emulate the X-axis deflection input and the Y-axis deflection input of an electron beam in a CRT display. In other words, the address and data signals used to display the stroke image on digital display 110 emulate the X-deflection input and the Y-axis input in a PAM of a CRT display.
PAM 120 may be any system, device, hardware (including software), or combinations thereof capable of determining the position of the stroke image being displayed on digital display 110. In one embodiment, PAM 120 is configured to determine the position of the stroke image based on data received from X-axis deflection input 113 and Y-axis deflection input 117. That is, PAM 120 is configured to determine the X and Y coordinates of the stroke image based on the data related to the X-plane from X-axis deflection input 113 and the data related to the Y-plane from Y-axis deflection input 117. Furthermore, PAM 120 is configured to calculate the position of the stroke image based on the X and Y coordinates, and generate a signal 123 and a signal 127 indicating the X-coordinate and the Y-coordinate, respectively. The data related to the X-plane from X-axis deflection input 113 and the data related to the Y-plane from Y-axis deflection input 117 is also provided to VIM 130.
VIM 130 may be any system, device, hardware (including software), or combinations thereof capable of modifying the intensity of a CRT stroke signal. In one embodiment, VIM 130 is configured to modify (e.g., attenuate or amplify) the intensity of stroke signal 105 supplied from MUX 140 to generate modified stroke signal 107 based on the vector velocity of the stroke image being displayed on digital display 110. Specifically, VIM 130 is configured to receive X-axis deflection input 113 and Y-axis deflection input 117, determine the vector velocity of the stroke image based on X-axis deflection input 113 and Y-axis deflection input 117, and attenuate or amplify stroke signal 105 based on the determined vector velocity. Specifically, once the vector velocity of the stroke image 105 is determined by VIM 130, a modifying velocity component is added to stroke signal 105 to generate modified stroke signal 107 so that the desired luminance of the stroke image being displayed on digital display 110 may be obtained. In other words, modified stroke signal 107 includes data emulating the vector velocity of a CRT electron beam based on X-axis deflection input 113, Y-axis deflection input 117, and the video intensity input 145, so that the stroke image being displayed on digital display 110 includes the desired level of luminance.
Difference circuit 1310 comprises a memory 1312, a memory 1314, and a subtractor circuit 1316 coupled to memory 1312 and 1314. Memory 1312 is configured to receive and, at least temporarily, store a first X-coordinate for the stroke image at time T1, and memory 1314 is configured to receive and, at least temporarily, store a second X-coordinate for the stroke image at time T2, which is subsequent to time T1. Subtractor circuit 1316 is configured to receive the first and second X-coordinates, and subtract the first X-coordinate from the second X-coordinate to determine an X-value representing the change in position of the stroke image in an X-axis.
Difference circuit 1320 comprises a memory 1322, a memory 1324, and a subtractor circuit 1326 coupled to memory 1322 and 1324. Memory 1322 is configured to receive and, at least temporarily, store a first Y-coordinate for the stroke image at time T1, and memory 1324 is configured to receive and, at least temporarily, store a second Y-coordinate for the stroke image at time T2. Subtractor circuit 1326 is configured to receive the first and second Y-coordinates, and subtract the first Y-coordinate from the second Y-coordinate to determine a Y-value representing the change in position of the stroke image in a Y-axis. The X-value and the Y-value are then transmitted to multiplier circuits 1330 and 1340, respectively.
Multiplier circuit 1330 is configured to square the X-value (i.e., (X-value)2) determined by difference circuit 1310. Similarly, multiplier circuit 1340 is configured to square the Y-value (i.e., (Y-value)2) determined by difference circuit 1320. The squared X-value and the squared Y-value are then transmitted to adder circuit 1350.
Adder circuit 1350 is configured to add the squared X-value and the squared Y-value to generate an XY-value representing the vector velocity of the stroke image. The XY-value is then transmitted to encoder circuit 1360.
Encoder circuit 1360 is configured to compare the XY-value to a predetermined level of luminescence for the stroke image to be displayed and generate a coefficient that attenuates or amplifies stroke signal 105 so that modified stroke signal 107 includes a coefficient that will produce the predetermined level of luminescence for the stroke image to be displayed on digital display 110. In one embodiment, the XY-value itself is the coefficient. In another embodiment, encoder circuit 1360 includes a look-up table and is configured to generate the coefficient by matching the XY-value to a coefficient in the look-up table that corresponds to the XY-value. In this embodiment, each coefficient includes values less than, equal to, or greater than one (1). That is, the coefficient is greater than 1 (which emulates decreasing the velocity of an electron beam) if the stroke image is moving too slowly, the coefficient is equal to 1 if the stroke image is moving at the proper velocity, and the coefficient is less than 1 (which emulates increasing the velocity of an electron beam) if the stroke image is moving too fast. The coefficient is then transmitted to multiplier 1370.
Multiplier 1370 is configured to receive stroke signal 105 and multiply stroke signal 105 by the coefficient received from encoder circuit 1360 to generate modified stroke signal 107. That is, modified stroke signal 107 increases or decreases the level of luminance of the stroke image to be displayed on digital display 110. Alternatively, modified stroke signal 107 would have the effect of increasing or decreasing the vector velocity of an electron beam in a CRT display. Modified stroke signal 107 is then transmitted to stroke image memory 155 (see
With reference again to
MUX 140 is coupled to a raster/stroke control input 150 configured to alternate between providing stroke signal 105 and raster video signal 165 to MUX 140. MUX 140 is further coupled to a video intensity signal 145 that provides the intensity for stroke signal 105 or the intensity for raster video signal 165. Furthermore, MUX 140 is configured to discriminate between stroke signals 105 and raster video signals 165, and transmit each stroke signal 105 along with its corresponding video intensity signal 145 to VIM 130 and transmit each raster video signal 165 along with its corresponding video intensity signal 145 to raster video image memory 160.
Raster video image memory 160 is configured to receive and store raster video signal 165 and its corresponding video intensity signal 145. As such, raster video signal 165 and its corresponding video intensity signal 145 are made available to graphics processor 170 via raster video image memory 160.
Graphics processor 170 may be any graphics processor known in the art or developed in the future. Graphics processor 170 is configured to receive the content of modified stroke signal 107 from stroke image memory 155, and raster video signal 165 from raster video image memory 160, and combine the corresponding respective video intensity signals 145 to digital display 110 in any manner known in the art that is capable of rendering stroke and raster images on digital display 110.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.
