Computer graphics processing and selective visual display system – Computer graphics processing – Graph generating
Reexamination Certificate
1998-03-26
2001-02-06
Brier, Jeffery (Department: 2779)
Computer graphics processing and selective visual display system
Computer graphics processing
Graph generating
C345S182000, C345S182000, C345S111000
Reexamination Certificate
active
06184898
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a waveform display utilizing frequency-based coloring and navigation.
There are at least three well known representations of a signal:
1. The spectrum or frequency domain representation is a two-dimensional graph in which amplitude is plotted versus frequency. All points of the graph are normally plotted using the same color. Time information is not evident.
2. The spectrogram is a three-dimensional graph in which frequency is plotted versus time and the points of the graph are rendered using colors or shades of gray to convey amplitude information.
3. The waveform display or time domain representation is a two-dimensional graph in which amplitude is plotted versus time. All points of the graph are normally plotted using the same color. Frequency information is not evident.
FIG. 1
shows a portion
10
of a typical waveform display derived from an audio signal, i.e. an electrical signal containing audio frequency components. The waveform display shown in
FIG. 1
is of the kind that might be presented by a display device having a display area composed of pixels
14
arranged in columns
18
. For convenience, the pixels
14
are shown in
FIG. 1
as having an aspect ratio (height: width) substantially less than one, but in practice the aspect ratio would normally be closer to one.
By way of example, the portion
10
of the waveform display represents an audio signal that has been sampled at intervals &tgr; and has been quantized to return the twenty values indicated at the bottom of FIG.
1
. Each column
18
of pixels is used to display a representation of the evolution of the signal over an interval 5&tgr;, so that the twenty sample values are represented by four columns. Typically, the background color of the display is white and the amplitude information is plotted by rendering selected pixels
14
with a contrasting foreground color or black. The pixels in the column that are rendered with the foreground color (or black) show a line segment connecting the maximum and minimum sample values within the interval represented by the column. Thus, in the leftmost column the pixels from −2 to +5 are rendered with the foreground color (or black), represented by solid diagonal shading.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention there is provided an improved method of representing time evolution of a signal during a signal epoch using a rectangular array of pixels in which each column of pixels is assigned to a time interval within the signal epoch, and wherein foreground pixels in a column of pixels form a line segment connecting minimum and maximum amplitude values within the time interval to which the column is assigned, wherein the improvement resides in rendering the foreground pixels in a column with a color that depends on frequency-dependent information relating to a time segment that includes the time interval.
In accordance with a second aspect of the present invention there is provided an improved method of displaying information regarding a signal of which amplitude and frequency vary with time, in which the signal is used to generate a time domain representation of the amplitude of the signal as a foreground waveform against a background, wherein the improvement resides in varying the color with which the waveform is displayed as a function of frequency-dependent information obtained from the signal.
In accordance with a third aspect of the present invention there is provided a computer programmed to process a signal that evolves with time during a signal epoch by partitioning the signal epoch into a plurality of consecutive time segments, processing the signal to extract frequency-dependent information that characterizes each time segment, assigning a value to each time segment based on the frequency-dependent information that characterizes the time segment, receiving a user input to select a time segment of the signal, determining whether the value assigned to another time segment matches the value assigned to the user selected time segment, and, if so, providing an output which emphasizes at least one such time segment.
In accordance with a fourth aspect of the present invention there is provided a method of navigating a signal record, comprising partitioning the signal record into a plurality of consecutive segments, processing the signal to extract frequency-dependent information that characterizes each time segment, assigning a value to each time segment based on the frequency-dependent information that characterizes the time segment, selecting a time segment of the signal, determining whether the value assigned to another time segment matches the value assigned to the user selected time segment, and, if so, emphasizing at least one such time segment.
In accordance with a fifth aspect of the present invention there is provided a computer programmed to generate a representation of time evolution of a signal during a signal epoch using a rectangular array of pixels in which each column of pixels is assigned to a time interval within the signal epoch, and wherein foreground pixels in a column of pixels form a line segment connecting minimum and maximum amplitude values within the time interval to which the column is assigned, wherein the computer is programmed to render the foreground pixels in a column with a color that depends on frequency-dependent information relating to a time segment that includes the time interval.
REFERENCES:
patent: 5553235 (1996-09-01), Chen et al.
patent: 5684945 (1997-11-01), Chen et al.
Patten Michael D.
Rice Stephen V.
Brier Jeffery
Comparisonics Corporation
Good-Johnson Motilewa
Smith-Hill John
Smith-Hill and Bedell
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