Abstract:
An apparatus and method of automatically digitizing analog video and stroke and with size and positioning information. This is accomplished using signal characteristics of the deflection waveforms and video signals together with the video synchronization and blanking timing. This allows analog real time positioning and scaling by synchronizing the video data and deflection information. The deflection information in the form of signals either or both horizontal or X axis and vertical or Y axis characteristics such as amplitude, peak or peak to peak, and zero crossing, can be used to determine the size or scaling for each axis independently.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based on U.S. Provisional Application Ser. No. 60/634,907 entitled “Display Video Positioning System” filed on Dec. 10, 2004, the teachings of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention (Technical Field) 
   The present invention relates to displays and more particularly to video display processing of deflection based raster signals. 
   2. Background Art 
   Conversion of analog display presentation, in an analog deflection based video system for a cathode ray tube (CRT) type display, allows the position and size of the image to be determined strictly by the deflection amplitudes and offsets. Many legacy display systems use horizontal and vertical deflection signals to provide position and scaling in conjunction with another signal, bright-up, or video to provide intensity for video images on CRTs. The problem occurs when these legacy display systems migrate to digital display technology. The size and position of a video image, in a general sense, on normal monitors and digital display systems is based on the timing relationship of synchronization signal characteristics. This is due to the video standard definitions of synchronization and blanking timing that govern the image boundaries and position. 
   The problem is that video position is based on deflection waveforms for older analog displays. The input horizontal and vertical deflection signals are modified by the image source to change the video presentation and appearance characteristics in position, size, and scale. The conversion of video to time based systems loses the video positional scaling and dimensional information. This can lead to positional inaccuracies of the video presentation when digitally sampled and displayed. 
   U.S. Pat. No. 5,099,179, entitled “Remote Raster/Stroke Display Calibration” describes a remote registration and calibration system for a hybrid video display. However, this device differs substantially in that it is a one-time calibration to compensate for receiver circuit offset and errors. 
   SUMMARY OF THE INVENTION 
   Disclosure of the Invention 
   The present invention provides an apparatus and method for automatically digitizing analog video and stroke and with size scaling and positioning information. This is accomplished using signal characteristics of the deflection waveforms and video signals together with the video synchronization and blanking timing. This allows for analog real time positioning and scaling by synchronizing the video data and deflection information. The deflection information in the form of signals either or both horizontal or X axis and vertical or Y axis characteristics such as amplitude, peak or peak to peak, zero crossing, can be used to determine the size or scaling for each axis independently. 
   A primary object of the present invention is to provide automatic calibration of the raster image relative to a stroke image 
   A primary advantage of the present invention is that it provides a method of automatically determining and displaying the changes in video format aspect ratio. 
   Another advantage of this invention is it automatically scales the incoming image to the same size an analog system would provide. 
   Yet another advantage is this invention will track in real time and correct the alignment position of video. 
   Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating a preferred embodiment of the invention and are not to be construed as limiting the invention. In the drawings: 
       FIG. 1  shows the preferred embodiment of the invention. 
       FIG. 2  shows the deflection and video waveforms using the embodiment of  FIG. 1 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Best Modes for Carrying Out the Invention 
     FIG. 1  shows the preferred embodiment of the present invention. Incoming video/bright-up  126  signals are normally synchronized by video sync detector phase lock loop (PLL) and timing clock generator  102 . Incoming intensity signal video/bright up  126  are input to analog to digital converter (ADC)  100  using a PLL clock  102  synchronously to convert the analog video into digital video for storage in an image memory  108 . The incoming digitized video intensity is then multiplexed using raster/stroke multiplexer (R/S MUX)  104  to separate raster portion  128  from the stroke portion  130  of the incoming image. Raster video  128  is then optionally filtered utilizing a digital image filter  106 . The storage in video image memory  108  is controlled by video image address control  110  logic function to facilitate frame buffering and/or de-interlacing. 
   The new process comprises deflection based video digitization using an automatic display video positioning and scaling system. The deflection digitization is normally captured by horizontal or X ADC  112  and by vertical or Y ADC  114 , creating X stroke data  150  and Y stroke data  152 . X stroke data  150  and Y stroke data  152  are combined with video/bright up  130  digitized intensity to provide a stroke image for rendering. The combination may be accomplished using beam former processing (not shown). The stroke image can be combined or overlaid on the background video stored in video image memory  108  in a subsequent process. The stroke intensity is multiplexed by raster/stroke signal  132  to be sent, with the stroke deflection data for addressing memory, to provide the complete stroke image. The video intensity is alternately multiplexed by raster/stroke signal  132  into R/S MUX  104  to be sent to video image memory  108  using the address control to provide the complete background video image. 
   Horizontal or X deflection signal  134  is synchronously digitized with X ADC  112  independently. The selection of raster deflection data is multiplexed by raster/stroke signal  132  using R/S Mux  116 . Horizontal blanking signal, H blank  138  or equivalent, is sent from PLL and clock generating circuitry  102 . X raster deflection data  142  is used by X size and position detector  120  to detect the horizontal positional and scaling factors of incoming video X deflection signals  134 . The X raster deflection data is filtered for stability within the X size and position detector  120 . 
   Y deflection signals  136  are synchronously digitized with Y ADC  114  independently. The selection of raster deflection data is multiplexed by the raster/stroke signal using R/S Mux  118 . Vertical blanking signal, V Blank  140  or equivalent, is sent from PLL and clock generating circuitry  102 . Y raster deflection data  144  is used by Y size and position detector  122  to detect the vertical positional and scaling factors of incoming video Y deflection signals  136 . The Y raster deflection data is filtered for stability within the Y size and position detector  122 . 
   The digitized X raster deflection data  142  values are multiplexed to X size and position detector  120  function using raster/stroke  132  signal R/S Mux  116 . X size and position detector  120  switch the digitized video X raster deflection data  142  to logic that can ascertain video image characteristics. The logic in this block determines the image properties utilizing timing signals from the PLL like horizontal blanking or some other equivalent trigger signal. The detection of positional and scaling encoder  124  uses a number of characteristics such as end points, center, slope or rate for detection of both the horizontal boundaries of the deflection during active video times. The center detection or any point in relation to horizontal timing can be used to determine the offset in the presented deflection video image. The X deflection characteristics are sent to scaling and positional encoder  124 . 
   The digitized Y raster deflection data  144  values are multiplexed to Y size and position detector  122  function using raster/stroke  132  signal R/S MUX  118 . Y size and position detector  122  switch the digitized raster video deflection to logic that can ascertain video image characteristics. The logic in this block determines the image properties utilized timing signals from the PLL like vertical blanking or some other equivalent trigger signal. Detection of positional and scaling encoder  124  uses a number of characteristics such as end points, center, slope or rate for detection of both the vertical boundaries of the deflection during active video times. The center detection or any point in relation to vertical timing can be used to determine the offset in the presented deflection video image. The Y deflection characteristics are sent to scaling and positional encoder  124 . 
   Scaling and positional encoder  124  will filter and calculate the results of X size and positional detector  120  and Y size and positional detectors  122  for determination of image characteristics. The aspect ratio of the displayed image can be determined by calculation of the horizontal and vertical deflection ramp, slopes, peak or peak to peak amplitudes. Pan scroll size factors  156  can be used with video image memory address and control  110 , to anti-alias the image and appropriately position both vertically and horizontally and scale the video digitized data in the memory. Scaling factors  154  can be input into digital image filter  106  to adjust the filter characteristics corresponding to the scaling of sampled data. The scaling size and filter comprise the zoom function for the video image processing using the address and control function. 
   Scaling and positional encoder  124  can calculate the horizontal position or image location using the center point or any point within the active horizontal time period. The horizontal start and stop image position can be used for a pan function to correctly position the image horizontally. 
   Scaling and positional encoder  124  can calculate the vertical position or image location using the center point or any point within the active vertical field or frame time period. The vertical start and stop image position can be used for a scroll function to correctly position the image horizontally. 
   The zoom functions can be used in combination with video filtering parameter changes along with address range values to control the image size scaling both horizontally and vertically. The pan function can use the start and or ending address control to horizontal position the image. The scroll function can use the start and or ending address control to vertical position the image. 
     FIG. 2  depicts the deflection and video waveforms using the preferred embodiment of the invention. Raster video period  160  is generated by X deflection  134  and Y deflection  136  signal and video/bright up  126  signal. X deflection  134  provides horizontal ramps for each line of video. Y deflection  136  signal provides the vertical deflection for all lines in a field or frame of video. The intensity is provided by video/bright up  126 . Stroke image  162  is generated during the vertical retrace period. X deflection  134  and Y deflection  136  and video/bright up  126  portion of the intensity, draw the stroke or cursive part of the image. Changing characteristics of X deflection  134  and Y deflection  136  can change the position size and aspect ratio of raster image  160 . Raster/stroke signal  132  is used to define which portion of X deflection  134 , Y deflection  136  and video/bright up  126  are associated with raster  160  or stroke  162 . The term bright up refers to the stroke portion of the intensity signal. The term video refers to the raster portion of the intensity signal. 
   The present invention can be used for calibration and alignment of any stroke and raster system. Another application would be automatic alignment for heads up displays (HUD) in conversion to digital systems. Image conversion for flight simulators is another potential use. The application could also apply to fabrication and control systems. 
   Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above, are hereby incorporated by reference.