CMOS sensor camera with on-chip image compression
First Claim
1. A method of providing pulsewidth modulated bitline and wordline signals for performing spatial to frequency transforms of analog signals from sensor elements of a CMOS sensor array, said transform being characterized by a basis function, comprising the steps of;
- dividing a wordline period into intervals, such that each interval has an accumulated pulsewidth corresponding to a coefficient of said basis function, thereby providing a pulsewidth modulated wordline signal; and
dividing a bitline period into said intervals and into subintervals, such that each subinterval of each interval has an accumulated pulsewidth corresponding to a coefficient of said basis function.
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Abstract
A digital camera (10) that has an array (11) of CMOS sensor elements (11a). The array (11) is read in a manner that performs spatial-to-frequency transforms for image compression on the analog output signals of the sensor elements. More specifically, wordlines (12) and bitlines (13) are pulsewidth modulated so that the coincidence of their “on” times corresponds to a desired coefficient of the basis function of the transform (FIGS. 3 and 4). Additional comparator circuitry (15), quantizers (16), and encoding circuitry (19) can be part of the same integrated circuit as the array (11).
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Citations
7 Claims
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1. A method of providing pulsewidth modulated bitline and wordline signals for performing spatial to frequency transforms of analog signals from sensor elements of a CMOS sensor array, said transform being characterized by a basis function, comprising the steps of;
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dividing a wordline period into intervals, such that each interval has an accumulated pulsewidth corresponding to a coefficient of said basis function, thereby providing a pulsewidth modulated wordline signal; and
dividing a bitline period into said intervals and into subintervals, such that each subinterval of each interval has an accumulated pulsewidth corresponding to a coefficient of said basis function. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification