CN101454649B - System and method for a high dynamic range sensitive sensor element array - Google Patents
System and method for a high dynamic range sensitive sensor element array Download PDFInfo
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- CN101454649B CN101454649B CN2006800421343A CN200680042134A CN101454649B CN 101454649 B CN101454649 B CN 101454649B CN 2006800421343 A CN2006800421343 A CN 2006800421343A CN 200680042134 A CN200680042134 A CN 200680042134A CN 101454649 B CN101454649 B CN 101454649B
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Abstract
A high dynamic range sensitive sensor element or array is provided which uses phase domain integration techniques to accurately capture high and low intensity images. The sensor element of the present invention is not limited by dynamic range characteristics exhibited by prior art solid-state pixel structures and is thus capable of capturing a full range of electromagnetic radiation to provide a high quality output image.
Description
Technical field
The present invention relates generally to the electronic imaging field, particularly a kind of method and apparatus that uses photometric measurement and transmit the raising image taking.
Background technology
Photograph is the imaging process by the effect of light.The condition that only is used usually, its frequency in electromagnetic radiation are in the visible scope of human eye.From object reflection or the light type that sends through the exposure of certain hour by an image recording sensor.Imageing sensor is at chemistry, for example photographic negative in nature; Also solid-state, the CCD and the cmos image sensor that use of digital camera and video camera for example.
Digital camera has a series of focused lights and generates the lens of image scene.But be not as traditional camera light to be focused on the egative film but light is focused on the imageing sensor, imageing sensor converts the electromagnetic radiation of light to electric charge.This imageing sensor is called as graphic element i.e. " pixel ".The relative intensity of the electromagnetic radiation that electric charge presentation video sensor is subjected to generally is used for a light intensity value and pixel to connect.
Fig. 1 is the parts block scheme of typical digital image processing system 10.System 10 comprises a signal source 100 and the signal processing chain that is made of integrator 110, analog to digital converter (ADC) 120 and DSP 130.Signal source 100 for example can be a sensor, and a for example response electromagnetic radiation is such as the light intensity sensor that shines the photogenerated electroresponse on it.
The output V of integrator 110
OUTIt is input to ADC 120.ADC 120 carries out analog to digital conversion.Analog-digital conversion function is being known in the art.Appear at the simulating signal V of ADC 120 input ends
OUTConvert the signal V of one of upright level of a desirable component to
D
This quality of signals is by to signal V
INCarry out the feature that the integrator 110 of integration promotes.Fig. 2 illustrates this signal boost.Waveform 200 is the combination by signal source 100 a normal value signal that generates and the additional noise of destroying this normal value signal.The integrator output that waveform 210 generates for response waveform input signal 200.Be not difficult to find out that the signal fluctuation that noise causes reduces in waveform 210.
Fig. 3 illustrates a typical image sensor circuit.Signal source 1000 is an optical sensor, for example a photodiode.Electric capacity 1040 is a simple integral device.The output that is input as signal source 1000 of integrator.Electric capacity 1040 is resetted by the switch 1050 that is in the close position before the beginning integral process.Switch 1050 was opened when integral process began, and the signal that the voltage on the capacitor 1040 begins to respond from signal source 1000 inputs changes.Switch 1030 closures when integral process finishes are to integrator output 1060V
OUTSampling.Fig. 3 is a schematic diagram.Principle those skilled in the art of other similar integrator that function is identical is known.
Integrator output 1060V
OUTUsually can't surpass by the added upper limit of available mains voltage.Supply voltage is in the prior art owing to the necessary demand of power consumption descends.Integrator output 1060 can't beyond supply voltage, and continuing increase as the integrator output signal after reaching supply voltage will be saturated.Fig. 4 A illustrates this state of saturation.The saturated output voltage that appears at reaches available mains voltage and can't respond in input signal does further to promote.The saturated system performance that causes of signal descends.The potential distortion of the output of the dot structure that constitutes by optical sensor 100 and integrator 110 that the dynamic range deficiency of by the photo-sensitive cell structure, definitely saying integrator structure of illustrating Fig. 4 A-4C causes.
The linearity of output that the line segment of Fig. 4 A (a) illustrates the constant input signal of integrator 110 response one varying level increases.This image sensor architecture is functional in the input light intensity causes the scope of linearity output of line segment (a); This image sensor architecture performance in the input light intensity causes the scope of saturated output of line segment (b) is bad.
This integrator output response shows the dynamic range deficiency.Shown in Fig. 4 A, this imageing sensor can display image dark portion sharpness but can not be shown the highlights sharpness.Can shown in Fig. 4 B and 4C, move this response.The dynamic range of this imageing sensor is constant in Fig. 4 B and 4C, but the response characteristic displacement.The dark portion of the response characteristic of Fig. 4 B and highlights sharpness poor display, but the response of the intermediate range of dubious portion is good.The response characteristic of Fig. 4 C shows the intermediate range sharpness of well sacrificing dark portion sharpness and a part of dubious portion for keeping the highlights sharpness.
Fig. 5 A is many pixels are driven into the pixel intensity of over-exposed image when saturated as among Fig. 4 A a histogram.Shown in Fig. 5 A, the maximum output valve of dot structure is ' 255 ', and institute's applying unit is ADC 120 output codes corresponding with the pixel output voltage.This light intensity makes the value that integrator 110 is saturated along with many optical sensors 100 one of the outputs of causing of exposing in the time shutter.The output code ' 255 ' that it is maximum output codes that this maximum (saturated) value of integrator 110 outputs causes ADC to generate 8 ADC.The shooting of this image is owing to these pixels that must accept the high-strength light input can't obtain sufficiently high output level and can't reach best in quality.The low gain of integrator 110 causes the optical image sensor output that must accept the high-strength light input to be lower than 255 output and to prevent high-end distortion with record.
The histogram of Fig. 5 B pixel intensity of under-exposed image that is many pixel light when being not enough to reach minimum output valve.Shown in Fig. 5 B, the minimum output valve of dot structure is ' 0 ', and institute's applying unit is ADC 120 output codes corresponding with the pixel output voltage.This light intensity is enough to cause the high value of minimum ADC output code along with the value that causes many optical sensor 100 outputs of exposing in the time shutter can't cause integrator 110 outputs one.
The quality of this image is owing to these pixels that must be subjected to the LOIHT input can't reach sufficiently high output level and can't reach best in quality.Distortion shown in Fig. 5 B histogram is corresponding with the single pixel distortion of Fig. 4 C.The high-gain of integrator 110 causes the output of the optical image sensor that must be subjected to the LOIHT input to prevent the low side distortion to write down output more than 0.
Fig. 6 illustrates the response curve of the dot structure that uses the establishment of diclinic rate technology.The non-linear extension of dynamic range shown in Figure 6 has prevented saturation effect, ties up to the resolution reduction that light intensity causes the image that is taken when very high but be radiated at nonlinear dependence between electromagnetic energy intensity and the sensor output on the sensor.
The combination of other scheme such as multiexposure, multiple exposure, the conversion of condition slope and logarithmic response dot structure are also disclosed.Multiexposure, multiple exposure combination, the conversion of condition slope and logarithmic response dot structure show performance decline and can't obtain high-performance image.
Integrator is saturated to be the limiting factor of dot structure dynamic range performance.The all ways that solve the integrator saturation problem are disclosed.A common trait of these disclosed ways is monitoring integrator output, and the state of saturation that detects the integrator discharge writes down this incident when beginning.This class way is because analog component is difficult to effective the execution in integrated circuit (IC) with carrying out non-standard accuracy of simulation to require.Near the enforcement of the precision comparator that can be under noise circumstance moves the saturated supply voltage of integrator output beginning is a difficult task that consumes power excessively, from but a kind of undesirable running status.
The difficult design of analog IC and carry out time-consuming.Preferably use through fully debugging, also made the standard building block of size, power consumption and optimized performance.The way that this class has been announced can't satisfy this requirement.
Summary of the invention
According to one aspect of the invention, a kind of method of the wide dynamic range read output signal that obtains from a dot structure comprises the following steps: to generate the response integrated value of a photo-sensitive cell to incidence electromagnetic radiation, wherein uses and responds relevant phase information by this.
According to another aspect of the present invention, one dot structure comprises and is used to respond the phase integral device that photo-sensitive cell and that electromagnetic radiation generates a signal is connected with photo-sensitive cell, in order to carrying out integration through the photo-sensitive cell of one period time shutter for the response of electromagnetic radiation by phase information.
By such setting, provide one no matter be radiated at the solid-state pixel that electromagnetic energy intensity on the sensor how can both the captured image of reliable reproduction.
Above-mentioned and other advantages below in conjunction with description of drawings the present invention.
Description of drawings
Fig. 1 is the block scheme of the parts in the image taking chain;
Fig. 2 is the synoptic diagram of integrator output;
Fig. 3 is the block scheme of a typical pixel structure;
Fig. 4 A-4C illustrates the influence of dynamic range deficiency for describing the transition curve of dot structure output distortion shown in Figure 3;
Fig. 5 A and 5B are respectively the histogram of the pixel intensity of over-exposed and under-exposed image;
Fig. 6 is the response curve of the dot structure of use diclinic rate technology foundation;
Fig. 7 A is the response curve of dot structure of the present invention;
Fig. 7 B is the histogram of pixel intensity in the captured image of the present invention;
Fig. 8 is the block scheme of the present invention according to the dot structure of ADC and DSP piece;
Fig. 9 is the block scheme of phase region integrator one embodiment of the present invention;
Figure 10 A and 10B are oscillator phase (9A) synoptic diagram and integrator output signal (9B) synoptic diagram, are used for describing signal integration performance of the present invention;
Figure 11 A is the waveform that the oscillator input of response diagram 11B changes the tunable oscillator of frequency;
Figure 12 is the synoptic diagram of quantized error to the low intensity signal influence;
Figure 13 A-13D is some common VCO output waveforms;
Figure 14 A and 14B are the synoptic diagram of phase unwrapping mechanism of the present invention;
Figure 15 has the block diagram of the sensor element of phase region integrator for the present invention;
Figure 16 is the process flow diagram of some steps of carrying out with Figure 14 phase region integrator in image shoot process.
Embodiment
According to one aspect of the present invention, provide a kind of wide dynamic range sensor element or array that uses the phase region Integral Technology accurately to take high low-luminosity picture.Sensor element of the present invention is not subjected to the restriction of the dynamic range performance that solid-state pixel structure showed of prior art, and the scope that therefore can take whole electromagnetic radiation provides high quality output image.
Fig. 7 A sets up the response synoptic diagram of sensor element for using the technology of the present invention.The dynamic range expanded of this sensor element is enough to make it to come irradiates light is responded at the pixel response on the whole electromagnetic radiation intensity scope.Avoid the saturation effect in the highlights of captured image when therefore, sensor element can be caught enough electric charge in the dark-part.Net effect is no matter how the electromagnetic energy relative intensity that is radiated on the sensor can both the captured image of reliable reproduction.
Fig. 7 B exports histograms of the pixel intensity of the correct exposure image in the 0-255 of 8 ADC dynamic range for all pixels.
Sensor element of the present invention comprises a novel integrator based on frequency oscillation circuit.Frequency oscillation circuit is the IC building block of standard, not the shortcoming of existing solid-state device.In addition, the accurate integration device that the disclosed sensor element of the application uses makes that output signal value can be considerably beyond available mains voltage, and has high precision and dynamic range is very big.
Require imageing sensor only to use a sensor reading step just can obtain the image of high resolving power and wide dynamic range for obtaining high-performance image.Fig. 8 illustrates dot structure of the present invention.Fig. 8 dot structure uses the existing signal of Fig. 3 to obtain structure, but replaces time-domain integration device 110 with novel phase region integrator 210.Fig. 9 is shown specifically phase region integrator of the present invention.
In the present invention, the output of signal source 100 (Fig. 8) is connected with the input 800 of Fig. 9 phase region integrator.The integration of input signal was sentenced phase format at phase region integrator output terminal 840 and is read when integration period finished.
Image sensor module, particularly integrator partly satisfy two standards: a) response generates very big output from the weak input signal of photo-sensitive cell; And b) avoids saturated from the input signal of photo-sensitive cell when very big.These two standards are mutually exclusive in existing solid-state structure.But the present invention recognizes that these two standards of phase region integrator of Fig. 9 all can be met by for example using.
From the notion of research integration, phase place, frequency and the relation between them, can fully understand the working condition of phase region integrator best.Integral function is that integration is the mathematical function that is known in the art.In brief, integration is the mathematic(al) object that area or broad sense area are regarded in an explanation as.Draw with a curve as a signal, the integration of this signal is the area of this curve below.Integrator is a kind of like this device, and a signal that appears at the input is carried out integration, generates the integration of an input signal in output place.
Phase place and frequency are differential relationships.One oscillator output V
OutTotal phase place of passing through in time Δ T is calculated by following formula
Δθ＝∫f
instdt＝∫(f
nom+f
gain·S
in)dt
Wherein, integrating range is time Δ T.
Separate each integral
Δθ＝∫(f
nom+f
gain·S
in)dt＝∫f
nomdt+∫f
gain·S
indt＝K+f
gain∫S
indt
Wherein, K one is fixed value f
NomWith the constant of the function of Δ T (integral time), be known therefore.
At f
NomThereby in the special case of=0 K=0
Δθ＝f
gain·∫S
indt
Second is fixed value f
GainWith input signal S
InIntegration ∫ S
InThe product of dt.The value that Δ θ value when time Δ T finishes deducts K can draw a f easily
Gain∫ S
InDt:
f
Gain∫ S
InDt=Δ θ-K and
∫S
indt＝(Δθ-K)/f
gain
At f
NomThereby in the special case of=0 K=0
∫S
indt＝Δθ/f
gain
Above-mentioned relation sets up VCO control input signals S among the time Δ T
InAnd the differential relationship between the phase delta θ that VCO or oscillator output are passed through.Figure 10 A and 10B are the curve map of this relation.Figure 10 A illustrates phase place that VCO output passes through and the funtcional relationship between the time.Figure 10 B illustrates input control signal S
INIntegration to the time.
Figure 11 A illustrates input signal S shown in the response diagram 11B
INThe output waveform of the voltage-controlled oscillator that generates.S
INBe made of two sections fixed values, first section 720 value among Figure 11 B is less than second section 730.
Get back to Figure 10 B, integrator deferent segment 620 is S
INDuring low value section 720 input integral devices as the integration output of the function of time.Integrator deferent segment 630 is S
INDuring high value section 730 input integral devices as the integration output of the function of time.
S
IN Low value section 720 causes the oscillation frequency of VCO to compare S
IN High value section 730 is low.Figure 11 A waveform segment 700 illustrates the low oscillation frequency of VCO.The S of VCO input
IN High value section 730 causes the VCO oscillation frequency to compare S
INThe low value section is high.Figure 11 A waveform segment 710 illustrates the VCO high oscillation frequency.
Figure 10 A illustrates phase place that VOC passes through and the funtcional relationship between the time.Section 600 is corresponding with VCO deferent segment 700.Section 610 is corresponding with VCO deferent segment 710.The phase accumulation rate of section 600 is lower than section 610.Phase accumulation rate as the function of time is the phase place that VCO passes through, and its unit is the per second radian.VCO is an oscillation frequency in order to the speed by unit of phase, and its unit also is the per second radian, and this is consistent with the accumulation of phase rate.
VCO control signal input waveform segment 720 causes VCO output waveform section 700.VCO output phase and the functional digraph formation curve section 600 that concerns between the time.
VCO control signal input waveform segment 730 causes VCO output waveform section 710.VCO output phase and the functional digraph formation curve section 610 that concerns between the time.
The waveform shape of Figure 10 A and 10B is identical, at f
NomThereby during=0 K=0 by constant f
GainRelated; And at f
NomThereby ≠ 0 K ≠ 0 o'clock is then by constant f
GainRelated with K.
Therefore can find out input signal S
INTime-domain integration on function with input signal S
INThe phase region integration identical.Input signal S
INTime-domain integration and input signal S
INThe phase region integration by two constant associations, one of constant is at f
NomBe 0 under=0 special case.
Use the inventive method to carry out signal integration and be better than existing integrator, solved a performance difficult problem relevant with existing integrator.An advantage is to have solved the problem that integrator output may be saturated.VCO or oscillator output strictly are limited in the upper lower limit value (peak value), under any circumstance all will not exceed.Therefore saturated situation can not appear exporting.
Another advantage is to have solved the quantize noise problem.As shown in figure 12, low level signal 310 can suffer significant and unacceptable quantize noise, does not almost have difference between the output voltage by the approaching input intensity generation of value.Based on phase measurement integrated metric Δ integral time T in the phase place passed through of oscillator output Δ θ.Phase place that oscillator output Δ θ passes through among the integral time Δ T and input control signal are integrated into direct ratio in integral time Δ T, both are directly proportional for this.Δ θ minimum value appears in the integration output minimum.But
f
gain·∫S
indt＝Δθ-K
Wherein, K is a constant.Therefore as long as regulate VCO gain f
GainJust can be for ∫ S
InAny set-point of dt is independently set Δ θ-K for one particular value, is comprised its minimum value.Thereby owing to can set the minimum value of the measured integrator output variable of gain of integrator, relevant quantize noise problem is eliminated.
Another advantage is, variable oscillation circuit is common, the basic building block of system of all kinds, so they are easy to obtain and height optimization.
Therefore based on the integrator of VCO in quantize noise and dynamic range or do not export aspect saturated superior more than existing integrator.Other advantage is open-and-shut to the common technician in this area.
Oscillator is the circuit that a class is known in the art.The output of oscillatory circuit can be different shape, but all is periodic, and promptly output waveform is repeatedly.The one replication of output waveform comprises an oscillation period, and the duration of one-period is called oscillation period.
Oscillation frequency f
OscBe defined as number oscillation period of unit interval, unit is hertz (per second number oscillation period).The angular frequency of an oscillator is defined as ω=2 π f by convention
Osc, pass through 2 π radian phasing degree θ a complete oscillation period.
Relevant with an oscillator is starting condition, i.e. the state of system when getting time t=0 for a certain.An example of starting condition is oscillator initial phase with radian tolerance when t=0.
Figure 13 A, B, C and D illustrate the common common output waveform of oscillatory circuit.As well known in the art, Figure 13 A, B, C and D illustrate the output waveform of sine, triangle, sawtooth and square-wave oscillator.In all these examples, shown in the voltage peak scope be 1v.
The oscillation frequency of electronic oscillating circuit can be fixed, and also can change.The variable common oscillator of oscillation frequency is voltage-controlled oscillator (VCO).One VCO has a voltage input end at least, signal voltage S
InIn this place's control oscillation frequency.Voltage is related with electric current by Ohm law, therefore we can say signal S
InBy its electric current rather than voltage-controlled oscillating frequency.
One VCO also can have nominal oscillation frequency f
NomThere is not frequency control input S
InVCO was not with f when level or its value did not change oscillation frequency such as 0v
NomVibration.Nominal oscillation frequency can be any particular value, comprises 0 hertz.
The output frequency of VCO becomes with the amplitude of input signal.Therefore the instant oscillation frequency of VCO and the nominal oscillation frequency of VCO differ the f that provides for following formula
Delta
f
inst＝f
nom+f
delta
Wherein
f
delta＝f
gain·S
in
F in this embodiment
DeltaUnit be the per second radian, f
GainUnit be the every volt radian of per second, S
InUnit be the volt.
As mentioned above, Figure 11 A illustrates the input and output signal of VCO.The oscillation frequency of VCO output becomes with the change of input signal amplitude.VCO deferent segment 700 is corresponding with input signal section 720.VCO deferent segment 710 is corresponding with input signal section 730.The oscillation frequency of VCO deferent segment 700 is lower than VCO deferent segment 710.The amplitude ratio input signal section 730 of input signal section 720 low.So f
GainFor on the occasion of, the VCO oscillation frequency is directly proportional with the input control signal amplitude.
VCO also can have other input end as resetting/activating.The effect when reset mode of resetting/activate is the VCO output waveform to be reset to its value can be a voltage predetermined voltage of arbitrary value in the peak value scope up and down.The effect that resets/activate when state of activation is to make VCO output vibration.
VCO has output V
OutV
OutThe angular phasing of each cycle by 2 π radians vibrates.That is, output phase is mensurable modulus 2 π, and the oscillator output valve that separates on each phase place of 2 π is all identical.Figure 13 A-13D illustrates some common VCO output waveforms.Each waveform is by 2 π radians among Figure 13 in a complete cycle, and the waveform values that all waveforms separate on each phase place of 2 π is all identical.
Following the drawing of phase place that oscillator output is passed through in the local period of one-period, in one-period the zero hour of this local period and the finish time to oscillator output sampling, draw after the phase place of each sample the calculating that subtracts of this two phase place.
The phase place that vibration output was passed through in period greater than an oscillation period can only be defined as modulus 2 π radians when using based on the method in two Direct observation VCO outputs constantly.Therefore for solving function of this smudgy increase, this function periodicity that output is passed through to VCO or effective mark of one-period are counted.
The periodicity that output was passed through in a time interval to VCO or effective mark of one-period are counted promptly, and the circuit of " expansion " phase place is easy to implement.The waveform relevant with this class circuit is illustrated among Figure 14 A and the 14B.VCO among Figure 14 A is output as triangular wave.At moment t=0,0.5T
pAnd T
pThe VCO output waveform reach with stroke be 0, π and 2 π radians are corresponding is designated as 900,910 and 920 state.
The output of phase unwrapping circuit is at t=0,0.5Tp and T
pThe time state become 0, the level of V and 2V amplitude.Elapsed time is designated as 930,940 and 950, and they are corresponding with the VCO output state that is designated as 900,910 and 920 respectively.
Shown in relation between the output of VCO output and phase unwrapping circuit on the one-period of VCO output can expand to any amount of VCO output cycle, VCO output each by its 0 and the predetermined quantity of value increase of the output of phase unwrapping circuit during π (modulus 2 π) phase value.Known as the scientific and technical personnel in this area, also available other method is implemented the phase unwrapping function and is indicated the value of the expansion phase place that VCO output is passed through.
Total phase place that VCO output is passed through is drawn by two sums.First total expansion phase place for phase unwrapping circuit record.Second total phase place of passing through after upgrading from the last time of phase unwrapping circuit output for VCO output.This amount can clearly be drawn by direct tolerance VCO output.
Figure 15 is the block scheme of VCO part of the ICL8038 of commercially available integrated circuit.The total phase place and the VCO that increased phase unwrapping in addition, pass through reset/mobilizing function.
When being subjected to the triggering of comparer 815 and 820, trigger 825 changes state.Comparer 815 triggers when capacitor 845 reaches predetermined high pressure.Comparer 820 triggers when capacitor 845 reaches predetermined low pressure.
Voltage on the capacitor 845 drops to comparer 820 triggerings when enough hanging down.Trigger 825 change states made switch 865 open when comparer 820 triggered.The electric current I of current source 855
1 Cause capacitor 845 chargings, thereby cause the voltage on the capacitor 845 to rise.Capacitor 845 powers on and presses the comparer 820 change states that cause immediately that rise.
Voltage on the capacitor 845 rises to that comparer 815 triggers again when enough high, causes trigger 825 change states, capacitor 845 charge/discharge repeatedly.
Pass between the voltage on the electric charge of capacitor 845 and the capacitor 845 is Q=CV, and wherein, C is the electric capacity of capacitor 845, and unit is a farad, and Q is the electric charge of being held on the capacitor 845, and unit is a coulomb, and V is the voltage on the capacitor 845, and unit is volt.
By the invariable current I change of holding electric charge on the capacitor 845 that a period of time Δ T causes of flowing is Δ Q=I Δ T, wherein, Δ Q is that unit is the electric charge change of being held on the capacitor 845 of coulomb, and I is that unit is the current value of ampere, and Δ T is that unit is the electric current flowing time interval of second.Invariable current makes electric charge that capacitor 845 is held and linear between the time.Electric charge that capacitor 845 is held and the linear change between the time make on the capacitor 845 voltage and be linear change between the time.
Are decided by the charging of capacitor 845 and discharge time current source 860 and 855 electric current I that generate
1And I
2Size.The trigger voltage level required time sum that capacitor 845 discharges and recharges comparer 815 and 820 is determining the oscillation period of VCO.So electric current I
1And I
2Size determining oscillation period and the frequency of VCO.
Thereby put on the control signal Control current source 860 and the 855 control VCO oscillation frequency at input end 870 places.Although not shown, can between the control signal that puts on 870 places and current source 860 and 855, increase by a simple voltage or a current diverter that is known in the art and regulate waveform symmetry.
The control of the state that oppositely is subjected to trigger 825 of voltage on the capacitor 845.Each trigger 825 changes state hour counters 835 correspondingly to be triggered and changes its output state.The change of counter 835 output states can be the change of voltage swing shown in Fig. 8 b.As long as state separately can be differentiated, also can use other voltage swing change method.Counter 835 outputs also can be and are the digital format that is made of a digital character code that comprises the B position.This moment, the change of its output state can be one or two system number, wherein, and different one or more expression different conditions.
Therefore trigger 825 each change state hour counters 835 change output states reach its minimum to VCO and peaked number of times is counted.Output state as counter 835 is an even number, and then VCO output is by the integral multiple of 2 π radians.Thereby the number of times of the 2 π radians that VCO output is passed through is drawn divided by 2 by the output counting of counter 835.
Output state as counter 835 is an odd number, and then VCO output is that an integer adds a mark by 2 π radian numbers.The VCO output integral part by 2 π radian numbers subtracts 1 number that draws by counter 835 output states and draws divided by 2.VCO output is decided by the ascent stage of this waveform and the asymmetric degree of descending branch by the fractional part of 2 π radian numbers, and the common technician in this area is easy to calculate this fractional part.For example, as the waveform ascent stage be two double-lengths of descending branch, then need just can finish 2/3 of oscillation period.
Voltage on the capacitor 845 is directly proportional with the phase place that the VCO output of trigger 825 last state change back is passed through.This area common technician can easily obtain, as the trigger voltage (being the minimum and maximum voltage of VCO output) of a) comparer 815 and 820 and b) asymmetric between ascent stage of VCO output waveform and the descending branch be known.For example, as a) VCO output voltage at waveform half place between minimum and the maximal value on the ascent stage, and b) the waveform ascent stage is two double-lengths of descending branch, then at place's tolerance waveform oscillation period 1/3.
The phase place sum of total phase place that the output of VCO is passed through for passing through with the VCO output of voltage and phase converter 840 sum counters and phase converter 835 records.This function is carried out by totalizer 880, can obtain at output terminal 890 places.
Thereby switch 850 resets to the initial voltage output of voltage source 810 to reset VCO oscillator output of capacitor 845.Trigger 825 is resetted by signal 895.The initial voltage of voltage source 810 is enough to determine the initial phase of VCO output waveform with the reset mode of trigger 825 and the asymmetric degree between VCO output waveform ascent stage and the descending branch.This derivation is being known in the art.
As known in the field and use as described in the document, use basic triangular waveform described herein to add internal circuit in addition and draw sine wave, square wave and sawtooth wave waveform as ICL9038.Therefore content described herein is equally applicable to the output waveform of other shape of VCO.
Therefore the present invention is used in the high-gain of the time integral of carrying out input signal in the phase region and the existing integrator in the wide dynamic range integrator replacement dot structure.
Figure 16 is the process flow diagram of some example steps in the image shoot process 150 of the dot structure of use phase region integrator of the present invention.
When the described time shutter begins (step 151), VCO output sum counter and phase converter 835 reset.Change its electrical characteristics in the exposure of step 152 photo-sensitive cell, make VCO output change frequency.This photo-sensitive cell can be any element of photodiode, photogate, phototransistor or photoresistance and so on.The invention still further relates to solid state image pickup device, for example be the CMOS or the MOS imaging device of the geometric configuration of pixel, its at least a portion pixel is as above structure.
Export the expansion phase place of passing through at step 153 counter and phase converter 835 record VCO.When determining that in step 154 exposure mechanism is through with the output of VCO, VCO is exported with phase converter 840 at step 155 voltage and to convert radian to.The output of counter and phase converter 835 and voltage and phase converter 840 is by total phase place totalizer 880 additions.Can convert the phase region integral result to the time-domain integration result in step 156 during as needs.This step of step 156 expression that is shown in broken lines is dispensable in shooting process.
A kind of method and apparatus in order to the read output signal that obtains a solid-state pixel structure (comprising the dot structure based on CCD, CMOS-and MOS-) has more than been described.This dot structure comprises at least one has the photo-sensitive cell of an output node, on phase region output signal node is carried out the device of integration and reads the device of phase region integrated value.Under this structure, provide a kind of no matter the solid-state pixel that the intensity that shines the electromagnetic energy on the sensor how can both image that reliable reproduction is taken the photograph.
Various embodiments of the present invention more than have been described, although be noted that some parts and process steps have been described, this explanation is exemplary; The common technician in this area can increase other functional description and other step and element, therefore the invention is not restricted to described specific embodiment.Various representative elements can be used on the hardware and software that moves on the computer and implement, and can make correction and change to illustrated embodiment in principle of the invention scope.Therefore, the present invention only is subjected to the qualification of the scope and spirit of appended claim.
Claims (14)
1. one kind is used for from the method for dot structure acquisition wide dynamic range read output signal, and described method comprises the following steps:
According to the response of a photo-sensitive cell, provide an output waveform of different frequency to the electromagnetic radiation of incident; With
By the accumulation phase place passed through of output waveform and the phase information of using output waveform, generate the integrated value of response.
2. the method for claim 1, wherein: provide described output waveform by voltage-controlled oscillator, described voltage-controlled oscillator can be operated the response that is used for receiving photo-sensitive cell.
3. the method for claim 1, wherein: photo-sensitive cell exposed to the open air in following a period of time of electromagnetic radiation, and wherein generate step further comprises the steps: to determine an output waveform when finishing during this period of time phase place, the cycle sum that the accumulation output waveform is passed through, and wherein integrated value is determined by described phase place and cycle sum.
4. method as claimed in claim 2 further comprises the step according to the frequency of electromagnetic radiation intensity regulation voltage control generator.
5. dot structure comprises:
The response electromagnetic radiation generates the photo-sensitive cell of a signal;
Oscillator can be operated the signal value that is used to respond from photo-sensitive cell one output waveform is provided; And
One both phase integrator that is connected with photo-sensitive cell is used for phase place of passing through by the accumulation output waveform and the phase information of using output waveform, and photo-sensitive cell is carried out integration to the response of electromagnetic radiation on one period time shutter.
6. dot structure as claimed in claim 5, wherein: described both phase integrator comprises the logical circuit that is used for the phase place that the accumulation output waveform is passed through in an integration period.
7. dot structure as claimed in claim 6, wherein: the described logical circuit that is used to accumulate the phase place of being passed through comprises the logical circuit that is used in the beginning of integration period and determines the phase differential of output waveform between finishing.
8. dot structure as claimed in claim 6, wherein: the logical circuit that is used to accumulate comprises that one is used to accumulate the accumulator of the cycle sum of the output waveform that is provided by oscillator.
9. dot structure as claimed in claim 5, wherein: described oscillator comprises the input end that is used for according to the intensity adjustments oscillator frequency of input signal.
10. dot structure as claimed in claim 5, wherein: described oscillator is a voltage-controlled oscillator.
11. dot structure as claimed in claim 5, wherein: described oscillator is a current control oscillator.
12. dot structure as claimed in claim 5, the input signal that can respond from photo-sensitive cell produces output, and wherein said output is greater than input signal.
13. dot structure as claimed in claim 5 can be by avoiding saturated from the signal of photo-sensitive cell.
14. the method for a photographic images comprises the steps:
One photo-sensitive cell is exposed under the electromagnetic radiation, to generate the sensor signal of one period time shutter of experience; And
The phase place that accumulation one oscillator wave is passed through between this exposure period, so that an integrator result to be provided, wherein said oscillator wave responds this sensor signal by oscillator and generates.
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| US72789705P | 2005-10-18 | 2005-10-18 | |
| US60/727,897 | 2005-10-18 | ||
| PCT/US2006/036794 WO2007035861A2 (en) | 2005-09-21 | 2006-09-21 | System and method for a high dynamic range sensitive sensor element or array |
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| CN101454649A CN101454649A (en) | 2009-06-10 |
| CN101454649B true CN101454649B (en) | 2011-04-27 |
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| CN200680042054.8A Expired - Fee Related CN101512543B (en) | 2005-09-21 | 2006-09-21 | High resolution and wide dynamic range integrator |
| CN2006800421413A Expired - Fee Related CN101454901B (en) | 2005-09-21 | 2006-09-21 | Broad dynamic range light-sensitive element or array system and method with gain control |
| CN2006800421343A Expired - Fee Related CN101454649B (en) | 2005-09-21 | 2006-09-21 | System and method for a high dynamic range sensitive sensor element array |
| CN2006800421964A Expired - Fee Related CN101365930B (en) | 2005-09-21 | 2006-09-21 | System and method for image sensor element or array with photometric and realtime reporting capabilities |
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| CN200680042054.8A Expired - Fee Related CN101512543B (en) | 2005-09-21 | 2006-09-21 | High resolution and wide dynamic range integrator |
| CN2006800421413A Expired - Fee Related CN101454901B (en) | 2005-09-21 | 2006-09-21 | Broad dynamic range light-sensitive element or array system and method with gain control |
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| CN2006800421964A Expired - Fee Related CN101365930B (en) | 2005-09-21 | 2006-09-21 | System and method for image sensor element or array with photometric and realtime reporting capabilities |
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| US9347890B2 (en) * | 2013-12-19 | 2016-05-24 | Kla-Tencor Corporation | Low-noise sensor and an inspection system using a low-noise sensor |
| WO2020227980A1 (en) * | 2019-05-15 | 2020-11-19 | 合刃科技（深圳）有限公司 | Image sensor, and light intensity sensing system and method |
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| CN1205150A (en) * | 1996-09-27 | 1999-01-13 | 马库斯·伯姆 | Local auto-adaptive optic sensor |
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| US5416616A (en) * | 1990-04-06 | 1995-05-16 | University Of Southern California | Incoherent/coherent readout of double angularly multiplexed volume holographic optical elements |
| KR100396203B1 (en) * | 1993-06-17 | 2003-12-31 | 소니 가부시끼 가이샤 | Exposure apparatus and method, video camera having the exposure apparatus |
| KR970701952A (en) * | 1994-12-30 | 1997-04-12 | 요트.게.아. 롤페즈 | Circuit and method for generating accurate guadrature signals |
| US6188056B1 (en) * | 1998-06-24 | 2001-02-13 | Stmicroelectronics, Inc. | Solid state optical imaging pixel with resistive load |
| US6757018B1 (en) * | 1998-12-18 | 2004-06-29 | Agilent Technologies, Inc. | CMOS image sensor with pixel level gain control |
| US6821245B2 (en) * | 2000-07-14 | 2004-11-23 | Xillix Technologies Corporation | Compact fluorescence endoscopy video system |
| JP3852324B2 (en) * | 2001-02-20 | 2006-11-29 | ティアック株式会社 | Signal processing circuit and signal processing method |
| US6867693B1 (en) * | 2001-07-25 | 2005-03-15 | Lon B. Radin | Spatial position determination system |
| US6809358B2 (en) * | 2002-02-05 | 2004-10-26 | E-Phocus, Inc. | Photoconductor on active pixel image sensor |
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- 2006-09-21 CN CN200680042054.8A patent/CN101512543B/en not_active Expired - Fee Related
- 2006-09-21 CN CN2006800421413A patent/CN101454901B/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1205150A (en) * | 1996-09-27 | 1999-01-13 | 马库斯·伯姆 | Local auto-adaptive optic sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101454901B (en) | 2011-04-27 |
| CN101454901A (en) | 2009-06-10 |
| CN101512543A (en) | 2009-08-19 |
| CN101365930A (en) | 2009-02-11 |
| CN101365930B (en) | 2011-08-17 |
| CN101454649A (en) | 2009-06-10 |
| CN101512543B (en) | 2013-04-24 |
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