Patents by Inventor Graeme Storm
Graeme Storm has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20120312963Abstract: Each column of pixels in an image sensor array has at least two column bitlines connected to an output of each pixel. A readout input circuit includes first inputs and a second input. Each first input is connected, via a capacitance, to a comparator input node. The second input is connected via a capacitance to the same comparator input node. The first inputs receive, in parallel, an analog signal acquired from the pixels via the column bitlines. The analog signals vary during a pixel readout period and have a first level during a first calibration period and a second level during a second read period with the analog signals being constantly read onto the capacitances during both the first calibration period and the second read period. The comparator compares an average of the signals on the plurality of first inputs to the reference signal.Type: ApplicationFiled: December 13, 2011Publication date: December 13, 2012Applicant: STMMicroelectronics (Research & Development) LimtedInventors: Graeme STORM, Matthew PURCELL, Derek TOLMIE, John Kevin MOORE, Michael WIGLEY
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Patent number: 8305474Abstract: An image sensor has a per-column ADC arrangement including first and second capacitors allowing a comparator circuit to perform correlated double sampling. The capacitors are continuously connected to, respectively, the analog pixel signal and a ramp signal without use of a hold operation. The comparator circuit comprises a differential input being connected to the junction of the two capacitors and being biased by a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential input as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast. Connectivity of the differential input stage allows the ramp signal to see a constant capacitive load thus reduce image artifacts referred to as smear.Type: GrantFiled: November 19, 2009Date of Patent: November 6, 2012Assignees: STMicroelectronics (R&D) Ltd., STMicroelectronics SA (Morocco), STMicroelectronics (Grenoble 2) SASInventors: Matthew Purcell, Graeme Storm, Derek Tolmie, Mhamed El Hachimi, Laurent Simony, Min Qu
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Patent number: 8134623Abstract: An image sensor has a per-column ADC arrangement including first and second capacitors for correlated double sampling, and a comparator circuit. The capacitors are continuously connected to, respectively, the analog pixel signal and a ramp signal without use of a hold operation. The comparator circuit comprises a differential amplifier having one input connected to the junction of the two capacitors and another input connected to a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential amplifier as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast.Type: GrantFiled: March 11, 2009Date of Patent: March 13, 2012Assignee: STMicroelectronics (Research & Development) Ltd.Inventors: Matthew Purcell, Graeme Storm, Min Qu
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Publication number: 20120006973Abstract: An image sensor includes an array of pixels. Each pixel has at least one photo-sensitive element. Readout circuitry receives an analog signal from each pixel at a first time and at a second time, between which the analog signal changes. The image sensor further includes associated support circuitry which is a source of time variant noise. The signal level at both first and second times includes pixel noise. Sample and hold circuitry is provided to maintain substantially level at least a proportion of this support circuitry noise time invariant at the sensor output between the first time and the second time.Type: ApplicationFiled: June 30, 2011Publication date: January 12, 2012Applicant: STMicroelectronics (Research & Development) LimitedInventors: Graeme Storm, Matthew Purcell
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Patent number: 8054210Abstract: An image sensor includes a pixel array, and a correlated double sample circuit coupled to one of the pixels in the pixel array. The correlated double sample circuit includes first and second inputs, and first and second sample capacitors respectively coupled to the first and second inputs. The first input is for receiving an analog signal from a pixel, and the second input is for receiving a time varying reference signal. The analog signal varies during a pixel readout period, and has a first level during a first reset period and a second-level during a second read period. A comparator circuit compares the time varying reference signal and the analog signal. The analog signal and the time varying reference signal are constantly read onto one of the first and second sample capacitors during both the first reset period and the second read period.Type: GrantFiled: January 17, 2008Date of Patent: November 8, 2011Assignee: STMicroelectronics (Research & Development) LimitedInventors: Matthew Purcell, Rachel Elliott, Graeme Storm
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Patent number: 7880779Abstract: The method and circuit corrects errors in an active pixel sensor which generates an output indicative of illumination intensity and which may experience an error in the output as a result of artifacts which produce an erroneous output. The approach includes determining the output from the pixel, comparing the output with a threshold value, and if the output is lower that the threshold value identifying the existence of an erroneous output and storing a value in a latching device in response thereto. A maximum value is generated in response to the latching device to replace the erroneous output, thereby correcting the error. The present invention switches the system from the analog to digital domain with respect to the issue of artifacts by using a latch to store a value which is then used to replace the actual output if the output is wrong.Type: GrantFiled: September 28, 2006Date of Patent: February 1, 2011Assignee: STMicroelectronics (Research and Development) LimitedInventor: Graeme Storm
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Patent number: 7804537Abstract: An image sensor includes an array of pixels, with each pixel including a photodiode, and a first output circuit for deriving a linear output signal by applying a reset signal to the photodiode and reading a voltage on the photodiode after an integration time. A second output circuit derives a logarithmic output signal by reading a near instantaneous illumination-dependent voltage on the photodiode that is a logarithmic function of the illumination. In the logarithmic mode, the pixels are calibrated to remove fixed pattern noise. The pixels may be operated in linear and log modes sequentially, with the linear output being selected for low light signals and the log output being selected for high light signals.Type: GrantFiled: April 8, 2004Date of Patent: September 28, 2010Assignee: STMicrolectronics Ltd.Inventors: Graeme Storm, Jonathan Ephriam David Hurwitz
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Publication number: 20100157035Abstract: An image sensor has a per-column ADC arrangement including first and second capacitors allowing a comparator circuit to perform correlated double sampling. The capacitors are continuously connected to, respectively, the analog pixel signal and a ramp signal without use of a hold operation. The comparator circuit comprises a differential input being connected to the junction of the two capacitors and being biased by a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential input as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast. Connectivity of the differential input stage allows the ramp signal to see a constant capacitive load thus reduce image artifacts referred to as smear.Type: ApplicationFiled: November 19, 2009Publication date: June 24, 2010Applicants: STMicroelectronics (Research & Development) Limited, STMicroelectronics SA (Morocco), STMicroelectronics (Grenoble 2) SASInventors: Matthew Purcell, Graeme Storm, Derek Tolmie, Mhamed El Hachim, Laurent Simony, Min Qu
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Publication number: 20090237536Abstract: An image sensor has a per-column ADC arrangement including first and second capacitors for correlated double sampling, and a comparator circuit. The capacitors are continuously connected to, respectively, the analog pixel signal and a ramp signal without use of a hold operation. The comparator circuit comprises a differential amplifier having one input connected to the junction of the two capacitors and another input connected to a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential amplifier as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast.Type: ApplicationFiled: March 11, 2009Publication date: September 24, 2009Applicant: STMicroelectronics (Research & Development) LimitedInventors: Matthew Purcell, Graeme Storm, Min Qu
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Publication number: 20080192126Abstract: An image sensor includes a pixel array, and a correlated double sample circuit coupled to one of the pixels in the pixel array. The correlated double sample circuit includes first and second inputs, and first and second sample capacitors respectively coupled to the first and second inputs. The first input is for receiving an analog signal from a pixel, and the second input is for receiving a time varying reference signal. The analog signal varies during a pixel readout period, and has a first level during a first reset period and a second-level during a second read period. A comparator circuit compares the time varying reference signal and the analog signal. The analog signal and the time varying reference signal are constantly read onto one of the first and second sample capacitors during both the first reset period and the second read period.Type: ApplicationFiled: January 17, 2008Publication date: August 14, 2008Applicant: STMicroelectronics (Research & Development) Limited, Country of Incorporation: United KingdomInventors: Matthew Purcell, Rachel Elliott, Graeme Storm
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Publication number: 20070075883Abstract: The method and circuit corrects errors in an active pixel sensor which generates an output indicative of illumination intensity and which may experience an error in the output as a result of artifacts which produce an erroneous output. The approach includes determining the output from the pixel, comparing the output with a threshold value, and if the output is lower that the threshold value identifying the existence of an erroneous output and storing a value in a latching device in response thereto. A maximum value is generated in response to the latching device to replace the erroneous output, thereby correcting the error. The present invention switches the system from the analog to digital domain with respect to the issue of artifacts by using a latch to store a value which is then used to replace the actual output if the output is wrong.Type: ApplicationFiled: September 28, 2006Publication date: April 5, 2007Applicant: STMcroelectronics (Research and Development) Ltd.Inventor: Graeme STORM
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Publication number: 20060066750Abstract: A rolling blade exposure system includes odd rows of a pixel array being read out with a short exposure time and even rows being read out at a long exposure time. Each pair of sampled rows are stitched together before to form a single output line. The resultant image is then formed from the output lines. The stitching process ensures that the resultant image has a wide dynamic range. This is achieved at the expense of a loss of resolution, but this loss is acceptable for certain applications.Type: ApplicationFiled: September 26, 2005Publication date: March 30, 2006Applicant: STMicroelectronics Ltd.Inventors: Robert Henderson, Matthew Purcell, Graeme Storm
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Publication number: 20040227109Abstract: An image sensor includes an array of pixels, with each pixel including a photodiode, and a first output circuit for deriving a linear output signal by applying a reset signal to the photodiode and reading a voltage on the photodiode after an integration time. A second output circuit derives a logarithmic output signal by reading a near instantaneous illumination-dependent voltage on the photodiode that is a logarithmic function of the illumination. In the logarithmic mode, the pixels are calibrated to remove fixed pattern noise. The pixels may be operated in linear and log modes sequentially, with the linear output being selected for low light signals and the log output being selected for high light signals.Type: ApplicationFiled: April 8, 2004Publication date: November 18, 2004Applicant: STMicroelectronics Ltd.Inventors: Graeme Storm, Jonathan Ephriam David Hurwitz
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Publication number: 20040227831Abstract: A logarithmic pixel is formed by a photodiode connected to a semiconductor device that is operating based upon a sub-threshold. A logarithmic output is taken from an output node connected to the pixel via an amplifier. To calibrate the pixel, the photodiode is isolated by a switch and a ramp voltage is applied as reference voltage to the amplifier. The ramp voltage acts across the constant internal capacitance of the pixel to produce in-pixel a constant current for calibration purposes.Type: ApplicationFiled: April 8, 2004Publication date: November 18, 2004Applicant: STMicroelectronics Ltd.Inventors: Graeme Storm, Jonathan Ephriam David Hurwitz