MULTISAMPLING WITH REDUCED BIT SAMPLES
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Accused Products
Abstract
A relatively non-complex signal processor supporting an active pixel sensor imaging system is disclosed. The signal processor only requires the first sample from a group of samples in a multiple sample to be transmitted to the signal processor at full resolution. The subsequent samples in that group can be transmitted using only a subset of least significant bits. The minimum number of required LSBs is based upon the level of noise in the system. In one embodiment, the number of LSBs transmitted is k+2 per sample, where k indicates the number bits corresponding to peak noise. In an alternative embodiment, each subsequent sample is transmitted using only k+1 bits.
16 Citations
45 Claims
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1-10. -10. (canceled)
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11. A method for recovering information represented by a plurality of untransmitted most significant bits in a subsequent sample of a group of samples where the first transmitted sample of the group is transmitted with full bit resolution and a noise value in the group of samples is equivalent to a k-bit signal, said method comprising:
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if a (k+2)-bit and a (k+1)-bit of the subsequent sample are respectively equal to 0 and 0, and if the (k+2)-bit of a first one of the plurality of samples is equal to 1, setting said untransmitted plurality of most significant bits to be equal to a corresponding set of most significant bits in said first one of the plurality of samples plus one; otherwise if the (k+2)-bit and (k+1)-bit of the subsequent sample are respectively equal to 1 and 1, and if the (k+2)-bit of the first one of the plurality of samples is equal to 0, setting said untransmitted plurality of most significant bits to be equal the corresponding set of most significant bits in said plurality of samples minus one; and otherwise setting said untransmitted plurality of most significant bits to be equal to the corresponding set of most significant bits in said first one of the plurality of samples.
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12. A method for recovering information represented by a plurality of untransmitted most significant bits in a subsequent sample of a group of samples where the first transmitted sample of the group is transmitted with full bit resolution and a noise value in the group of samples is equivalent to a k-bit signal, said method comprising:
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if a (k+1)-bit and a k-bit of the subsequent sample are respectively equal to 0 and 0, and if a (k+1)-bit and k-bit of a first sample are respectively equal to 1,1, setting said untransmitted plurality of most significant bits to be equal to a corresponding set of most significant bits in said first one of the plurality of samples plus 1; otherwise if the (k+1)-bit and the k-bit of the subsequent sample are respectively equal to 0 and 1, and if the (k+1)-bit, k-bit, and (k−
1)-bit are respectively equal to 1, 1, and 1, setting said untransmitted plurality of most significant bits to be equal to a corresponding set of most significant bits in said first one of the plurality of samples plus 1;otherwise if the (k+1)-bit and the k-bit of the subsequent sample are respectively equal to 1 and 0, and if the (k+1)-bit, k-bit, and (k−
1)-bit are respectively equal to 0, 0, and 0, setting said untransmitted plurality of most significant bits to be equal to a corresponding set of most significant bits in said first one of the plurality of samples minus 1;otherwise if the (k+1)-bit and the k-bit of the subsequent sample are respectively equal to 1 and 1, and if the (k+1)-bit, and k-bit are respectively equal to 0 and 0, setting said untransmitted plurality of most significant bits to be equal to a corresponding set of most significant bits in said first one of the plurality of samples minus 1; otherwise if the (k+1)-bit and the k-bit of the subsequent sample are respectively equal to 1 and 1, and if the (k+1)-bit, k-bit, and (k−
1)-bit are respectively equal to 0, 1, and 0, setting said untransmitted plurality of most significant bits to be equal to a corresponding set of most significant bits in said first one of the plurality of samples minus 1; andotherwise setting said untransmitted plurality of most significant bits to be equal to the corresponding set of most significant bits in said first one of the plurality of samples.
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13. A method for computing the sum of a plurality of sample values, comprising:
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calculating a sum of only a same number of least significant bits of each sample value; calculating a magnitude from a subset of bits of said plurality of sample values; shifting and zero-filling said magnitude; combining said sum and said magnitude to produce a least significant bits portion of a result; shifting and zero-filling a most significant bits portion of a first one of said plurality of samples to produce a most significant bits portion of the result; and forming said sum of a plurality of sample values using said least significant bits portion of the result with said most significant bits portion of the result. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21-30. -30. (canceled)
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31. An imaging system comprising:
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a pixel array that receives an image and provides output signals indicating pixel values resulting from the image; a sample-and-hold circuit that receives and stores output signals from the pixel array; an analog-to-digital converter, that receives stored output signals from the sample-and-hold circuit and obtains, for each output signal, a digital value; a buffer that receives and stores digital values from the analog-to-digital converter; and a signal processor, including a control circuit which receives digital value from said buffer, in a format wherein each bit of a first one of said plurality of samples is in the transmission, only a least significant bits portion of each subsequent one of said plurality of samples is in the transmission, and said least significant bits portion of each subsequent sample has a same number of least significant bits, said same number being a function of noise within said stored digital values. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method for sampling a plurality of values, each having N bits, the values indicating a sensed input, comprising:
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sampling all N bits of a first value; for a subsequent value, sampling M least significant bits where M is less than N; and combining the N bits of the first value with the M bits of the subsequent value to obtain an average value for the sensed input.
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44. A method for processing multiple digital samples of a pixel signal, said method comprising:
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receiving all bits of one of said multiple digital samples; receiving a predetermined number of least significant bits of the remaining ones of said multiple digital samples, said predetermined number being related to the magnitude of signal difference among said multiple digital samples; and processing said received bits to produce a digital signal representing a combination of said multiple digital samples.
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45. A method for recovering information represented by a plurality of untransmitted most significant bits in a subsequent sample of a group of samples where the first transmitted sample of the group is transmitted with full bit resolution and a noise value in the group of samples is equivalent to a k-bit signal, said method comprising:
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subtracting from the transmitted portion of a subsequent sample a corresponding portion of the first transmitted sample to arrive at an intermediate result; recovering the untransmitted portion of the subsequent sample as being equal to the corresponding portion of the first transmitted sample if the intermediate result is less than the maximum value of a k-bit signal and greater than the minimum value of negative one times the maximum value of a k-bit signal; recovering the untransmitted portion of the subsequent sample as being equal to the corresponding portion of the first transmitted sample minus one if the intermediate result is greater than the maximum value of a k-bit signal; and recovering the untransmitted portion of the subsequent sample as being equal to the corresponding portion of the first transmitted sample plus one if the intermediate result is less than negative one times the maximum value of a k-bit signal.
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Specification