ENDOSCOPE SYSTEM
An endoscope system may include: an insertion section that is inserted into an object under examination, having an image capturing unit that successively outputs a pixel signal of a strength responsive to the amount of light of the pixel, and a time converter that converts the intensity of the pixel signal to time information representing a time interval by a time width and that transmits the converted time information; a transfer section that guides the outside of the object under examination the time information transmitted from the time converter; and an external apparatus positioned outside the object under examination, having a time interval converter that receives the time information guided by the transfer section and converts to a digital signal and outputs the intensity of the pixel signal represented by the received time information and an image processing unit that outputs an image responsive to the pixel signal.
1 . An endoscope system comprising:
an insertion section that is inserted into an object under examination, having an image capturing unit that successively outputs a pixel signal of a strength responsive to the amount of light of the pixel, and a time converter that converts the intensity of the pixel signal to time information representing a time interval by a time width and that transmits the converted time information;
a transfer section that guides the outside of the object under examination the time information transmitted from the time converter; and
an external apparatus positioned outside the object under examination, having a time interval converter that receives the time information guided by the transfer section and converts to a digital signal and outputs the intensity of the pixel signal represented by the received time information and an image processing unit that outputs an image responsive to the pixel signal that has been converted to the digital signal by the time interval converter.
2 . The endoscope system according to claim 1 , wherein
the insertion section further comprises a plurality of sample-and-hold circuits that sample and hold the pixel signals output from the image capturing unit and that output the sampled and holed pixel signals,
the time converter comprises a plurality of time converters each corresponding to one of the plurality of sample-and-hold circuits,
each of the plurality of sample-and-hold circuits successively repeats the sampling and holding of the pixel signals successively output from the image capturing unit,
each of the plurality of time converters converts to the time information and transmits intensities of the pixel signals sampled and held by the corresponding sample-and-hold circuit,
the time interval converter is constituted by a plurality of time interval converters each corresponding to one of the plurality of time converters,
each of the plurality of time interval converters converts to a digital signal each of the intensities of the pixel signals from the corresponding time information guided by the transfer section corresponding to one of the plurality of time converters, and
the image processing unit outputs the image based on the pixel signals that are converted to the digital signals by the plurality of time interval converters.
3 . The spectroscope according to claim 1 , wherein
the time converter converts the intensity of one pixel signal to the plurality of time information represented by different time intervals and transmits the result,
the time interval converter comprises a time interval converter that converts to the digital signals the plurality of time intervals of the one pixel signal represented by each of the time information guided by the transfer section, and further comprises a selecting device that selects and outputs one digital signal from the converted digital signals related to the time intervals for which conversion succeeded within a signal processing time pre-established by the time interval converter.
4 . The endoscope system according to claim 3 , wherein the selecting device selects a converted digital signal related to the longest one of the time intervals for which conversion succeeded within the pre-established signal processing time.
5 . The endoscope system according to claim 1 , wherein
the time converter comprises an inverter circuit that inverts and outputs an input signal at a time responsive to the intensity of the pixel signal, and
the input signal represents the intensity of the pixel signal as a time interval, based on the time of a pre-established number of inversions by the inverter circuit.
6 . The endoscope system according to claim 5 , wherein
the image processing unit divides a given signal by the digital signal converted by the time interval converter.
7 . The endoscope system according to claim 6 , wherein
the time converter comprises an optical transmitting unit that converts to an optical signal the timing of the start of the time interval and the timing of the end of the time interval included in the time information,
the transfer section comprises an optical waveguide that transfers the optical signal transmitted by the time converter, and
the time interval converter comprises an optical-to-electrical converter that converts the optical signal transferred by the transfer section to an electrical signal.
8 . The endoscope system according to claim 7 , wherein
the time interval converter comprises:
a timing detection unit that detects the timing of the start of the time interval and the timing of the end of the time interval included in the received time information, and outputs a starting signal representing the detected timing of the start of the time interval and an ending signal representing the detected timing of the end of the time interval;
a clock output unit that comprises a delay circuit and an oscillator and outputs a plurality of clocks of different phases;
a plurality of counting units that count the edges at which a clock output by the clock output unit changes from one state to another state and output the number of counted edges; and
an adder circuit that adds the counted numbers output by each of the counting units and outputs the number of the sum resulting from the addition as the digital signal, wherein
the clock output unit starts output of a plurality of clocks having different phases when a starting signal representing the timing of the start of the time interval is input, and
each of the plurality of counting units corresponds to one of the plurality of clocks having different phases, counts the edges of the corresponding clock up until the input of the ending signal representing the timing of the end of the time interval, and outputs each of the counted numbers.
9 . The endoscope system according to claim 8 , wherein
the oscillator can change the frequency of the clock that is output in response to an input parameter,
the time interval converter further comprises a parameter adjustment unit that outputs a parameter that controls the frequency of the clock output by the oscillator, and
the parameter adjustment unit, by adjusting the parameter, adjusts the frequency of the clock output by the oscillator and adjusts the timing of the edge of the clock that is output by the clock output unit.
10 . The endoscope system according to claim 9 , wherein
the parameter adjustment unit comprises:
a plurality of second delay circuits that delay and output an input signal and that are connected in series;
two second oscillators that correspond to each of the two different second delay circuits of the plurality of second delay circuits, and from the time of the input of a delayed operation starting signal representing the start of operation of the parameter adjustment unit, output a clock having a frequency responsive to the input parameter from the corresponding second delay circuit;
a phase comparator circuit that compares the timing of the edges of clocks output by the two second oscillators, and outputs phase comparison information representing a time difference between the timing of the compared edges; and
a parameter setting circuit that, based on the phase comparison information, calculates a parameter controlling the frequency of the clocks output by the second oscillators for the purpose of controlling so that the timing of the edges of the clocks output by the two compared second oscillators coincides, and outputs the calculated parameter as a parameter controlling the frequency of the clocks output by the oscillator and second oscillators.
11 . The endoscope system according to claim 8 , wherein
the delay circuit that, in response to an input parameter, can change the delay time by which an input signal is delayed,
the time interval converter further comprises a parameter adjustment unit that outputs a parameter that controls a delay time when the delay circuit delays and outputs an input signal, and
the parameter adjustment unit, by adjusting the parameter, adjusts the delay time when the delay circuit delays and outputs an input signal, adjusts the timing of the start of the output of the clock by the oscillator or the timing of the clock that has been output by the oscillator, and adjusts the timing of the edge of a clock output by the clock output unit.
12 . The endoscope system according to claim 11 , wherein
the parameter adjustment unit comprises:
a plurality of second delay circuits that are connected in series and that delay and output an input signal by a delay time responsive to an input parameter;
two second oscillators that correspond to each of the two different second delay circuits of the plurality of second delay circuits, and from the time of the input of a delayed operation starting signal representing the start of operation of the parameter adjustment unit, output clocks having the same frequency from the corresponding second delay circuit;
a phase comparator circuit that compares the timing of the edges of clocks output by the two second oscillators, and outputs phase comparison information representing a time difference between the timing of the compared edges; and
a parameter setting circuit that, based on the phase comparison information, calculates a parameter controlling the delay time of the second delay circuit for the purpose of controlling so that the timing of the edges of the clocks output by the two compared second oscillators coincide, and outputs the calculated parameter as a parameter controlling the delay circuit and the delay time of the second delay circuit.
13 . The endoscope system according to claim 10 , wherein
the plurality of second delay circuits connected in series comprise a part of a plurality of delay elements in a ring oscillator constituted by the delay elements connected in a ring configuration.
14 . The endoscope system according to claim 13 , wherein
the delay circuit and the second delay circuits are buffer circuits in which two inverting (logical negation) circuits having offset threshold voltages are connected in series.
15 . The endoscope according to claim 14 , wherein
if the buffer circuit is configured with the threshold voltage of the first inverter circuit stage set to be lower than the threshold voltage of the following inverter circuit stage,
the power supply voltage of the following inverter circuit stage is set to be lower than the power supply voltage of the first inverter circuit stage, and
if the buffer circuit is configured with the threshold voltage of the first inverter circuit stage is to be set to be higher than the power supply voltage of the following inverter circuit stage,
the power supply voltage of the first inverter circuit stage is set to be higher than the power supply voltage of the following inverter circuit stage.
16 . The endoscope system according to claim 12 , wherein
the plurality of second delay circuits connected in series comprise a part of a plurality of delay elements in a ring oscillator constituted by the delay elements connected in a ring configuration.
17 . The endoscope system according to claim 16 , wherein
the delay circuit and the second delay circuits are buffer circuits in which two inverting (logical negation) circuits having offset threshold voltages are connected in series.
18 . The endoscope according to claim 17 , wherein
if the buffer circuit is configured with the threshold voltage of the first inverter circuit stage set to be lower than the threshold voltage of the following inverter circuit stage,
the power supply voltage of the following inverter circuit stage is set to be lower than the power supply voltage of the first inverter circuit stage, and
if the buffer circuit is configured with the threshold voltage of the first inverter circuit stage is to be set to be higher than the power supply voltage of the following inverter circuit stage,
the power supply voltage of the first inverter circuit stage is set to be higher than the power supply voltage of the following inverter circuit stage.
19 . An A/D converter comprising:
a transmitting unit that has a voltage/time converter converting a magnitude of an analog input signal that has been input to time information representing a time interval by a time width, outputting the results, and transmitting the time information output by the voltage/time converter;
a transfer section that guides the time information transmitted from the transmitting unit to a position distanced from the transmitting unit;
a receiving unit that receives the time information guided by the transfer section, has a time/digital converter converting to a digital signal and outputting the magnitude of the analog input signal represented by the received time information, and outputs the digital signal output by the time/digital converter; and
a signal processing unit that performs a pre-established signal processing with respect to the digital signal output by the receiving unit so as to output as an ultimate digital signal the digital signal on which signal processing has been performed, wherein
the voltage/time converter converts the analog input signal to the time information so that, when taking Vin as the analog input signal and D as the time information to which the analog input signal has been converted, the relationship between the analog input signal Vin and the time information D becomes a first-order rational function relationship represented by the equation:
D=b /( V in− a )
where a is an arbitrary real number, and b is an arbitrary real number other than 0, and the signal processing unit performs signal processing that divides an arbitrary digital signal other than 0 by the digital signal output by the receiving unit so as to generate a digital signal having a first-order function relationship, and outputs the generated digital signal as the ultimate digital signal.
20 . The A/D converter according to claim 19 , wherein
the voltage/time converter converts the magnitude of one analog input signal to the plurality of time information represented by different time intervals,
the transmitting unit transmits the plurality of time information converted by the voltage/time converter,
the time/digital converter comprises a time/digital converter that converts to each of the digital signals the plurality of time intervals of one analog input signal represented by the corresponding time information guided by the transmitting unit, and
the receiving unit selects and outputs, from among the plurality of time information, one converted digital signal related to the time information for which the conversion has been completed within a signal processing time pre-established by the time/digital converter.
21 . The A/D converter according to claim 20 , wherein
the receiving unit selects, among from the time information for which the conversion has been completed within the pre-established signal processing time, a converted digital signal related to the time information representing the longest time interval.
22 . The A/D converter according to claim 19 , wherein
the voltage/time converter comprises an inverter circuit that inverts and outputs an input signal at a time responsive to the magnitude of the analog input signal, and
the input signal represents the magnitude of the analog input signal as a time interval, based on the time of a pre-established number of inversions by the inverter circuit.
23 . The A/D converter according to claim 19 , wherein
the transfer section comprises an optical waveguide that transfers the optical signal transmitted by the transmitting unit,
the transmitting unit converts time information that is an electrical signal and transmits the optical signal, and
the receiving unit receives the optical signal transferred by the transfer section and converts the received optical signal to the time information that is an electrical signal once again.