Abstract: A pixel circuit for a ultra-low power image sensor, including: an integration node, on which a photodiode current is integrated, a comparator arranged to compare a voltage at the integration node with a reference voltage, a n+1 bits digital memory, a writing pulse signal generator arranged to generate a writing pulse signal, on the basis of the comparator output voltage and on the voltage at a memory node, the start of the pulse triggering the writing of the digital word in the n-bits digital memory part. The comparator includes a switch in series with a current source and arranged to be commanded by the voltage at the memory node so that the switch is open at the end of the pulse, so as to drastically limit the consumption of static power of the pixel circuit during the integration phase.

Abstract: A pixel circuit for a ultra-low power image sensor, including: an integration node, on which a photodiode current is integrated, a comparator arranged to compare a voltage at the integration node with a reference voltage, a n+1 bits digital memory, a writing pulse signal generator arranged to generate a writing pulse signal, on the basis of the comparator output voltage and on the voltage at a memory node, the start of the pulse triggering the writing of the digital word in the n-bits digital memory part. The comparator includes a switch in series with a current source and arranged to be commanded by the voltage at the memory node so that the switch is open at the end of the pulse, so as to drastically limit the consumption of static power of the pixel circuit during the integration phase.

Abstract: A one-dimension position measurement system includes: a first ruler having a first one-dimension binary code si applied thereon, a camera for acquiring a picture of a portion of the code si, the portion having a length of I bits, and some processing elements. Each codeword of length I of the one-dimension code si is unique within the whole code si. A codeword ai is read from the acquired picture, and the processing elements are implemented for computing an absolute position p of the codeword ai of the code si from: (I). An ad-hoc interpolation method is used to obtain a precision way below the distance between two bits of the codewords. The code si may be applied on the ruler by using some geometric primitives, a geometric primitive for encoding a “1” being different from a geometric primitive for encoding a “0”, both having the same horizontal projection. The horizontal projection is then used for fine interpolation, achieving nanometer-scale resolution.

Abstract: A digital vision sensor includes a pixel array (10) for receiving a light beam representing a visual scene. The sensor includes: a reference voltage Vref generator; in each pixel, an element for generating, during an integration phase, a voltage Vp that is proportional to the received lighting and a comparator (30) for determining the moment when the voltage Vp thereof reaches the reference voltage; a logarithmic period generator for generating a clock having a period that increases proportionally to the time elapsed from the beginning of the integration; a device for counting the number of clock periods elapsed from the beginning of the integration and providing a result in the form of a binary code; a static RAM memory word (50) per pixel; and, in each pixel, an element (40) for writing the code present at the moment into the memory.

Abstract: A one-dimension position measurement system includes: a first ruler having a first one-dimension binary code si applied thereon, a camera for acquiring a picture of a portion of the code si, the portion having a length of I bits, and some processing elements. Each codeword of length I of the one-dimension code si is unique within the whole code si A codeword ai is read from the acquired picture, and the processing elements are implemented for computing an absolute position p of the codeword ai of the code si from: (I). An adhoc interpolation method is used to obtain a precision way below the distance between two bits of the codewords. The code si may be applied on the ruler by using some geometric primitives, a geometric primitive for encoding a “1” being different from a geometric primitive for encoding a “0”, both having the same horizontal projection. The horizontal projection is then used for fine interpolation, achieving nanometre-scale resolution.

Abstract: A DC-DC converter includes an induction coil cooperating with two switches, which operate alternately, to supply output voltage of a determined level relative to input voltage. The converter control method includes, in each cycle, a first phase of first duration with first switch controlled to make it conductive, and to increase current in the induction coil, and a second phase with second switch controlled to be conductive and to decrease current in the induction coil during a second adjustable time period. Detection device detects, at the end of the second phase, sign of overvoltage across one terminal of the induction coil connected to the switches, and supplies a detection signal kept in a high or low state, depending upon sign of detected overvoltage. Timing device receives detection signal for adapting, in each successive cycle, the second duration of the second phase to cancel out current in the induction coil.

Abstract: A digital vision sensor includes a pixel array (10) for receiving a light beam representing a visual scene. The sensor includes: a reference voltage Vref generator; in each pixel, an element for generating, during an integration phase, a voltage Vp that is proportional to the received lighting and a comparator (30) for determining the moment when the voltage Vp thereof reaches the reference voltage; a logarithmic period generator for generating a clock having a period that increases proportionally to the time elapsed from the beginning of the integration; a device for counting the number of clock periods elapsed from the beginning of the integration and providing a result in the form of a binary code; a static RAM memory word (50) per pixel; and, in each pixel, an element (40) for writing the code present at the moment into the memory.

Abstract: A DC-DC converter includes an induction coil cooperating with two switches, which operate alternately, to supply output voltage of a determined level relative to input voltage. The converter control method includes, in each cycle, a first phase of first duration with first switch controlled to make it conductive, and to increase current in the induction coil, and a second phase with second switch controlled to be conductive and to decrease current in the induction coil during a second adjustable time period. Detection device detects, at the end of the second phase, sign of overvoltage across one terminal of the induction coil connected to the switches, and supplies a detection signal kept in a high or low state, depending upon sign of detected overvoltage. Timing device receives detection signal for adapting, in each successive cycle, the second duration of the second phase to cancel out current in the induction coil.

Abstract: The invention relates to a method of calculating the local contrast at each pixel (PC) in a network (Mp) of photosensitive pixels which are arranged in at least one dimension (x, y). The inventive method consists in, during successive image acquisition cycles, producing a signal which is representative of the local luminance at each pixel, said luminance-representative signals being integrated values of luminance values sensed by the respective pixels (pC, pG, pD, pH, pB). The inventive method consists in: sampling the integrated values of the signals representing the luminance values at the pixels adjacent (pG, pD, pH, pB) to a considered pixel (pC), said sampling taking place at an instant in the cycle when the integrated value of the luminance at the considered pixel (pC) is equal to a pre-determined reference value; and determining the local contrast at the considered pixel (pC) on the basis of values thus sampled.

Abstract: The invention relates to a method of calculating the local contrast at each pixel (PC) in a network (Mp) of photosensitive pixels which are arranged in at least one dimension (x, y). The inventive method consists in, during successive image acquisition cycles, producing a signal which is representative of the local luminance at each pixel, said luminance-representative signals being integrated values of luminance values sensed by the respective pixels (pC, pG, pD, pH, pB). The inventive method consists in: sampling the integrated values of the signals representing the luminance values at the pixels adjacent (pG, pD, pH, pB) to a considered pixel (pC), said sampling taking place at an instant in the cycle when the integrated value of the luminance at the considered pixel (pC) is equal to a pre-determined reference value; and determining the local contrast at the considered pixel (pC) on the basis of values thus sampled.

Abstract: An electronic circuit for a capacitive flash analog to digital converter for converting the ratio of first and second analog signals into a digital code representation using an array of parallel capacitive comparator branches. Each branch computing one bit of the digital code simultaneously according to its array index. The first analog signal is applied as a voltage difference between first signal nodes comprising a first positive signal node and a first negative signal node. The second analog signal is, applied as a voltage difference between second signal nodes comprising a second positive signal node and a second negative signal node.

Abstract: An electronic circuit for measuring the position of a spatially periodic intensity pattern of incident radiation includes an array of detectors (1); two or more correlator units (2, 3) each having arrays of capacitors (12, 13) connected to a buffer (14); and a phase angle computing unit (4). The pitch of the array of detectors (1) is smaller than the pitch of the incident intensity pattern so that the latter is oversampled, yielding high accuracy. The detector outputs (17) are weighted by respective fixed capacitance values (15, 16) which vary periodically along arrays of capacitors (12, 13), and a weighted sum of outputs for each correlator unit (2, 3) is output at its respective buffer (14). The capacitance values (15, 16) of respective correlator units (2, 3) are mutually offset by a predetermined phase shift. The analog computation using capacitor arrays (12, 13) is fast and energy efficient, and can be implemented as a VLSI circuit.