1. An imaging device, comprising:
an imaging element configured to take an image of a target object and output an analog image signal corresponding to the image;
a storage unit configured to store therein a zero-point adjustment reference value, the zero-point adjustment reference value being a value to adjust a zero point in a level of the analog image signal output from the imaging element, the storage unit including a register of the imaging element;
a brightness detecting unit configured to detect a brightness of the target object; and
a reference-value changing unit configured to change the zero-point adjustment reference value stored in the storage unit when the brightness detected by the brightness detecting unit is equal to or lower than a threshold.
2. The imaging device according to claim 1, further comprising:
a gamma correcting unit configured to perform gamma correction on the image signal using a gamma value; and
a gamma-value changing unit configured to change the gamma value when the reference-value changing unit has changed the zero-point adjustment reference value.
3. The imaging device according to claim 1, further comprising:
an amplifying unit configured to amplify the image signal by a gain,
wherein the reference-value changing unit is configured to change the zero-point adjustment reference value only when the gain by which the amplifying unit amplifies the image signal has reached an upper limit.
4. The imaging device according to claim 3, wherein the reference-value changing unit is configured to change the zero-point adjustment reference value only when the brightness detected by the brightness detecting unit is equal to or lower than the threshold and the gain by which the amplifying unit amplifies the image signal has reached the upper limit.
5. A method of changing a zero-point adjustment reference value performed by an imaging device, the imaging device including an imaging element configured to take an image of a target object and output an analog image signal corresponding to the image and a storage unit configured to store therein the zero-point adjustment reference value and a zero point in a level of the analog image signal output from the imaging element is adjusted by using the zero-point adjustment reference value, the method comprising:
detecting brightness of the target object; and
changing the zero-point adjustment reference value stored in the storage unit when the brightness detected at the detecting is equal to or lower than a threshold, the storage unit including a register of the imaging element.
6. A computer program product that includes a non-transitory computer-readable recording medium and computer program stored on the recording medium which when executed on a computer causes the computer to function as:
a storage unit configured to store therein a zero-point adjustment reference value, the zero-point adjustment reference value being a value to adjust a zero point in a level of an analog image signal output from an imaging element, the analog image signal corresponding to an image of a target object, the storage unit including a register of the imaging element;
a brightness detecting unit configured to detect a brightness of the target object; and
a reference-value changing unit configured to change the zero-point adjustment reference value when the brightness detected by the brightness detecting unit is equal to or lower than a threshold.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of modulating a carrier signal generated by a non-linear dynamical system by embedding an information signal into said carrier signal, said method comprises:
multiplying the said information signal by a constant to produce a first signal value;
adding the first signal value and the nominal rate of evolution of the dynamical system to generate a second signal value;
providing a feedback path that includes that a first and second path, wherein input to said first path is the integration of a multiplication of said second signal and output of said second path, and the input to said second path is output of said first path, such that said second path is a first function that defines said non-linear dynamical system; and
providing said output of said first path as input to a second function that produces a transmitted signal, wherein said a non-linear dynamical system includes an attractor that is either periodic, almost periodic, quasi-periodic, or chaotic.
2. The method of claim 1, wherein said non-linear system has a known exponentially convergent observer.
3. The method of claim 2, wherein said first function has a periodic attractor.
4. The method of claim 2, wherein said first function has quasi-periodic attractor.
5. The method of claim 2, wherein said first function has a chaotic attractor.
6. A system for demodulating a transmitted signal, said system comprising:
an observer component that receives as input a transmitted signal and a rate estimate and produces an estimate of a state of a demodulator, such that said observer is exponentially convergent to the transmitter state when there is no modulation present in a modulator associated with said transmitted signal; and
a rate estimator that receives as input the transmitted signal and estimate of a state of said demodulator to produce an estimate of the modulating signal, wherein
said observer component and rate estimator are interconnected in a feedback arrangement, such that said arrangement recovers an information signal associated with said transmitted signal.
7. A method of demodulating a transmitted signal, said method comprising:
receiving as input a transmitted signal and a rate estimate;
producing an estimate of a state of a demodulator; and
utilizing said transmitted signal and said estimate of said state of said demodulator to produce said rate estimate, such that an information signal associated with said transmitted is recovered.
8. A method of modulating data comprising:
providing a non-linear dynamical system with an attractor that is either periodic, almost periodic, quasi-periodic, or chaotic;
modulating the rate of the evolution of the state on the attractor; and
transmitting a scalar function of state variables of the modulated non-linear dynamical system.
9. A system for demodulating a transmitted signal, said system comprising:
an observer component that receives as input a transmitted signal and a rate estimate and produces an estimate of a state of a demodulator, such that said observer component converges exponentially when no modulating signal is present in a modulator associated with said transmitted signal,
a rate estimator that receives as input the transmitted signal and estimate of said state of said demodulator to produce said rate estimate, and
a low-pass filter that receives said rate estimate and removes spectral energy that lies in a predefined frequency range from said rate estimate, wherein
said observer component and rate estimator are interconnected in a feedback arrangement, wherein said low pass filter is interconnected between said observer component and rate estimator, such that said arrangement recovers an information signal associated with said transmitted signal.