CCD signal read-out circuit free from ailiasing of high-frequency noises

Claim 2

A charge coupled device (CCD) signal read-out circuit for receiving a first signal output from a CCD and for substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from the reset noise, the first signal including a plurality of pixel periods each pixel period comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and extracting a feed-through signal and a pixel signal from each respective pixel period; first and second low-pass filter circuits for low-pass filtering the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively; a signal hold circuit for sampling and holding the feed-through signal filtered by said first low-pass filter circuit; and a differential amplifier for subtracting the pixel signal filtered by said second low-pass filter circuit from a signal sampled and held by said signal hold circuit and outputting a resultant signal as the second signal.

Claim 3

A CCD signal read-out circuit according to claim 1, wherein said CCD is a color image sensor for producing a plurality of color signals, and wherein said CCD signal read-out circuit is provided for each of color signal.

Claim 4

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD, and substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from reset noise, the first signal including a plurality of pixel period each pixel period comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and extracting a feed-through signal and an associated pixel signal from each respective pixel period; first and second low-pass filter circuits for low-pass filtering the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively; a delay circuit for delaying the feed-through signal filtered by said first low-pass filter circuit until the associated pixel signal period comes; and a differential amplifier for subtracting the pixel signal filtered by said second low-pass filter circuit from a signal delayed by said delay circuit and outputting a resultant signal as the second signal.

Claim 5

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD, and substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from reset noise, the first signal including a plurality of pixel period each pixel period comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and extracting a feed-through signal and an associated pixel signal from each respective pixel period; first and second low-pass filter circuits for low-pass filtering the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively; a delay circuit for delaying the feed-through signal filtered by said first low-pass filter circuit until the associated pixel signal period comes; and a differential amplifier for subtracting the pixel signal filtered by said second low-pass filter circuit from a signal delayed by said delay circuit and outputting a resultant signal as the second signal.

Claim 6

A CCD signal read-out circuit according to claim 3, wherein said CCD is a color image sensor for producing a plurality of color signals, and wherein said CCD signal read-out circuit is provided for each of color signal.

Claim 7

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD, and substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from the reset noise, the first signal including a plurality of pixel periods, each comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: a delay circuit for delaying the first signal until a pixel signal period comes and producing a delayed signal; a first signal extractor circuit for receiving the delayed signal and extracting a feed-through signal from each pixel period; a second signal extractor circuit for receiving the first signal and extracting the pixel signal from each pixel period; first and second low-pass filter circuits for low-pass filtering the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively; and a differential amplifier for subtracting the pixel signal filtered by said second low-pass filter circuit from the feed-through signal filtered by said first low-pass filter circuit and outputting a resultant signal as the second signal.

Claim 8

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD, and substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from the reset noise, the first signal including a plurality of pixel periods, each comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: a delay circuit for delaying the first signal until a pixel signal period comes and producing a delayed signal; a first signal extractor circuit for receiving the delayed signal and extracting a feed-through signal from each pixel period; a second signal extractor circuit for receiving the first signal and extracting the pixel signal from each pixel period; first and second low-pass filter circuits for low-pass filtering the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively; and a differential amplifier for subtracting the pixel signal filtered by said second low-pass filter circuit from the feed-through signal filtered by said first low-pass filter circuit and outputting a resultant signal as the second signal.

Claim 9

A CCD signal read-out circuit according to claim 5, wherein said CCD is a color image sensor for producing a plurality of color signals, and wherein said CCD signal read-out circuit is provided for each of color signal.

Claim 10

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD, and substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from the reset noise, the first signal including a plurality of pixel periods, each pixel period comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and extracting a feed-through signal and a pixel signal from each respective pixel period; first and second averaging means for averaging the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits and for phase shifting at least one of: said averaged feed-through signal and said averaged pixel signal to bring both of the signals in phase; and a differential amplifier for producing a difference between signals outputted from said first and second averaging means and outputting a resultant signal as the second signal.

Claim 11

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD, and substantially removing a reset noise from the first signal by correlated double sampling to produce a second signal that is substantially free from the reset noise, the first signal including a plurality of pixel periods, each pixel period comprising a reset period, a feed-through period, and a pixel signal period, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and extracting a feed-through signal and a pixel signal from each respective pixel period; first and second averaging means for averaging the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits and for phase shifting at least one of: said averaged feed-through signal and said averaged pixel signal to bring both of the signals in phase; and a differential amplifier for producing a difference between signals outputted from said first and second averaging means and outputting a resultant signal as the second signal.

Claim 12

A CCD signal read-out circuit according to claim 7, wherein said first and second averaging means each comprise: first and second low-pass filter circuits for low-pass filtering the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively; and first and second peak detector circuits for detecting substantial peaks of the feed-through signal and the pixel signal filtered by said first low-pass filter circuit and said second low-pass filter, respectively to produce said averaged feed-through signal and said averaged pixel signal.

Claim 13

A CCD signal read-out circuit according to claim 7, wherein said first and second averaging means each comprise: first and second integrator circuits for integrating the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively to produce said averaged feed-through signal and said averaged pixel signal.

Claim 14

A CCD signal read-out circuit according to claim 7, wherein said CCD is a color image sensor for producing a plurality of color signals, and wherein said CCD signal read-out circuit is provided for each of color signal.

Claim 15

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD including a plurality of pixel periods, each pixel period comprising a feed-through period and a signal period, and for substantially reducing a correlated noise and a high-frequency noise included in the signal period to produce a second signal that is substantially free from the correlated noise and the high-frequency noise, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and for extracting levels of the feed-through period and the signal period for each respective pixel period to develop a feed-through signal and a pixel signal; a signal inverter circuit for inverting one of the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively, and for outputting a resultant signal in the form of a serial signal; and an averaging circuit for averaging the serial signal output from said signal inverter circuit to produce a signal in which the correlated noise and the high-frequency noise have substantially been reduced.

Claim 16

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD including a plurality of pixel periods, each pixel period comprising a feed-through period and a signal period, and for substantially reducing a correlated noise and a high-frequency noise included in the signal period to produce a second signal that is substantially free from the correlated noise and the high-frequency noise, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and for extracting levels of the feed-through period and the signal period for each respective pixel period to develop a feed-through signal and a pixel signal; a signal inverter circuit for inverting one of the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively, and for outputting a resultant signal in the form of a serial signal; and an averaging circuit for averaging the serial signal output from said signal inverter circuit to produce a signal in which the correlated noise and the high-frequency noise have substantially been reduced.

Claim 17

A CCD signal read-out circuit according to claim 11, further comprising a signal hold circuit for sampling and holding the signal output from said averaging circuit and outputting a resultant signal as the second signal.

Claim 18

A CCD signal read-out circuit according to claim 11, wherein said averaging circuit comprises an integrator circuit for integrating the serial signal over one pixel period.

Claim 19

A CCD signal read-out circuit according to claim 12, wherein said averaging circuit comprises an integrator circuit for integrating the serial signal over one pixel period.

Claim 20

A CCD signal read-out circuit according to claim 11, wherein said averaging circuit comprises a low-pass filter circuit for low-pass filtering the serial signal.

Claim 21

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a including a plurality of pixel periods, each pixel period comprising a feed-through period and a signal period, and for substantially reducing a correlated noise and a high-frequency noise included in the signal period to produce a second signal that is substantially free from the correlated noise and the high-frequency noise, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and for extracting levels of the feed-through period and the signal period for each respective pixel period to develop a feed-through signal and a pixel signal; a signal inverter circuit for inverting one of the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively, and for outputting a resultant signal in the form of a serial signal; a selector circuit for selecting from said serial signal a part of said serial signal for a first pixel period for developing a first serial signal, and selecting from said serial signal a part of said serial signal for a second pixel period for developing a second serial signal; a first averaging circuit for averaging the first serial signal to output a signal wherein the correlated noise and the high-frequency noise have substantially been reduced; and a second averaging circuit for averaging the second serial signal to output a signal wherein the correlated noise and the high-frequency noise have substantially been reduced.

Claim 22

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a including a plurality of pixel periods, each pixel period comprising a feed-through period and a signal period, and for substantially reducing a correlated noise and a high-frequency noise included in the signal period to produce a second signal that is substantially free from the correlated noise and the high-frequency noise, said CCD signal read-out circuit comprising: first and second signal extractor circuits for receiving the first signal and for extracting levels of the feed-through period and the signal period for each respective pixel period to develop a feed-through signal and a pixel signal; a signal inverter circuit for inverting one of the feed-through signal and the pixel signal extracted by said first and second signal extractor circuits, respectively, and for outputting a resultant signal in the form of a serial signal; a selector circuit for selecting from said serial signal a part of said serial signal for a first pixel period for developing a first serial signal, and selecting from said serial signal a part of said serial signal for a second pixel period for developing a second serial signal; a first averaging circuit for averaging the first serial signal to output a signal wherein the correlated noise and the high-frequency noise have substantially been reduced; and a second averaging circuit for averaging the second serial signal to output a signal wherein the correlated noise and the high-frequency noise have substantially been reduced.

Claim 23

A CCD signal read-out circuit according to claim 16, further comprising: a first sampling circuit for sampling the signal output from said first averaging circuit in time with the first pixel period; a second sampling circuit for sampling the signal output from said second averaging circuit in time with the second pixel period; and a signal holding circuit for holding the signals sampled by said first and second sampling circuits and outputting the sampled signals in serial form as the second signal.

Claim 24

A CCD signal read-out circuit according to claim 16, wherein the first signal is a color image signal including a plurality of color components, the first pixel period being a pixel period for a first color component, the second pixel period being a pixel period for a second color component.

Claim 25

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD including a plurality of pixel periods, each pixel period comprising a feed-through period and a signal period, and for substantially reducing a correlated noise and a high-frequency noise included in the signal period to produce a second signal that is substantially free from the correlated noise and the high-frequency noise, said CCD signal read-out circuit comprising: a first signal extractor circuit for receiving the first signal and extracting levels of the feed-through period and the signal period during a first pixel period to develop a first feed-through signal and a first pixel signal; a second signal extractor circuit for receiving the first signal and extracting levels of the feed-through period and the signal period during a second pixel period to develop a second feed-through signal and a second pixel signal; a first signal inverter circuit for inverting one of the first feed-through signal and the first pixel signal and outputting a resultant signal as a first serial signal; a second signal inverter circuit for inverting one of the second feed-through signal and the second pixel signal and outputting a resultant signal as a second serial signal; a first averaging circuit for averaging the first serial signal output from said first signal inverter circuit to output a signal wherein the correlated noise and the high-frequency noise have substantially been reduced.

Claim 26

A charge-coupled device (CCD) signal read-out circuit for receiving a first signal outputted from a CCD including a plurality of pixel periods, each pixel period comprising a feed-through period and a signal period, and for substantially reducing a correlated noise and a high-frequency noise included in the signal period to produce a second signal that is substantially free from the correlated noise and the high-frequency noise, said CCD signal read-out circuit comprising: a first signal extractor circuit for receiving the first signal and extracting levels of the feed-through period and the signal period during a first pixel period to develop a first feed-through signal and a first pixel signal; a second signal extractor circuit for receiving the first signal and extracting levels of the feed-through period and the signal period during a second pixel period to develop a second feed-through signal and a second pixel signal; a first signal inverter circuit for inverting one of the first feed-through signal and the first pixel signal and outputting a resultant signal as a first serial signal; a second signal inverter circuit for inverting one of the second feed-through signal and the second pixel signal and outputting a resultant signal as a second serial signal; a first averaging circuit for averaging the first serial signal output from said first signal inverter circuit to output a signal wherein the correlated noise and the high-frequency noise have substantially been reduced.

Claim 27

A CCD signal read-out circuit according to claim 19, further comprising: a first sampling circuit for sampling the signal output from said first averaging circuit in time with the first pixel period; a second sampling circuit for sampling the signal output from said second averaging circuit in time with the second pixel period; and a signal holding circuit for holding the signals sampled by said first and second sampling circuits and outputting, sampled signals in serial as the second signal.

Claim 28

A CCD signal read-out circuit according to claim 19, wherein the first signal is a color image signal including a plurality of color components, the first pixel period being a pixel period for a first color component, the second pixel period being a pixel period for a second color component.