# US 2013/0155239 A1 · Image sensor with improved dynamic range > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0155239 A1 - Document ID: US20130155239A1 - Status: Published application - Kind: A1 - Application number: 13/710,981 - Filed: 2012-12-11 - Published: 2013-06-20 - Earliest claimed: 2011-12-15 - Assignees: STMicroelectronics (Grenoble 2) SAS; STMicroelectronics (R&D) Ltd. - Inventors: John Kevin Moore; Matthew Purcell; Graeme Storm; Tarek Lule - Web page: https://patentgrep.com/patent/US20130155239A1 ## CPC - H04N 25/134: {based on three different wavelength filter elements} - H04N 25/00: Circuitry of solid-state image sensors [SSIS]; Control thereof - H04N 25/533: by using differing integration times for different sensor regions - H04N 25/70: SSIS architectures; Circuits associated therewith - H04N 25/77: Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components - H10F 39/12: Image sensors - H10F 39/15: Charge-coupled device [CCD] image sensors - H10F 39/802: {Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes} - H10F 39/8053: {Colour filters} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract An image sensor having improved dynamic range includes a signal that is read out for a selection of pixels which act as a calibration to govern the choice of exposure levels to be applied to the rest of the array. In this way, the sensor is operable to adapt to variations in scene intensity. The pixels in the array are vertically and horizontally addressed so as to enable accounted for small areas of intensity variation across an imaged scene. ## Claims ### Claim 1 A method of imaging a scene with a digital image sensor comprising a pixel array, comprising the steps of: performing a reset operation across one row of the pixel array; integrating pixels in said row for a first calibration time; at the end of said first calibration time, reading pixel values of said row of pixels; comparing said pixel values with one or more predetermined thresholds; and setting subsequent exposure levels for pixels in the pixel array based upon said compared pixel values. ### Claim 2 (depends on 1) The method of claim 1, wherein setting subsequent exposure levels for pixels in the pixel array comprises controlling a timing of reset signals applied to individual pixels by vertically and horizontally addressing the pixels in the pixel array. ### Claim 3 (depends on 1) The method of claim 1, wherein comparing said pixel values with one or more predetermined thresholds comprises comparing the pixel values with the values of a DAC ramp, and stepping values of said DAC ramp according to the one or more predetermined thresholds. ### Claim 4 (depends on 1) The method of claim 1, further comprising storing as decision data the exposure levels which are set for pixels in the pixel array based upon said pixel values read out at the end of said calibration time. ### Claim 5 (depends on 4) The method of claim 4, wherein said decision data is used to control the gain of an analog readout circuit. ### Claim 6 (depends on 4) The method of claim 4, further comprising applying low pass filtering to successive decision data. ### Claim 7 (depends on 4) The method of claim 4, wherein storing comprises storing only changes in decision data that apply from one pixel to another. ### Claim 8 A digital image sensor, comprising: a pixel array; and control circuitry arranged to: perform a reset operation across one row of the pixel array; integrate pixels in said row for a first calibration time; at the end of said calibration time, read pixel values of said row of pixels; compare said pixel values with one or more predetermined thresholds; and set subsequent exposure levels for pixels in the pixel array based upon said pixel values. ### Claim 9 (depends on 8) The digital image sensor of claim 8, wherein pixels within the array have a structure that comprises a photoelectric conversion device connected to a transfer gate transistor which is operable to selectively connect the photoelectric conversion to or disconnect the photoelectric conversion from the remainder of the pixel circuitry. ### Claim 10 (depends on 8) The digital image sensor of claim 8, wherein pixels within the array comprise multiple transistors to enable the pixel transfer gate operation to be dependent upon two input signals. ### Claim 11 (depends on 10) The digital image sensor of claim 10, wherein a first transfer gate transistor is connected to a vertical pixel address line and a second transfer gate transistor is connected to a horizontal pixel address line, such that charge will be transferred from the pinned photodiode to the floating diffusion node only when both the vertical and horizontal address lines are driven high. ### Claim 12 (depends on 10) The digital image sensor of claim 10, wherein a first transfer gate transistor is connected at its gate to the source of a second transfer gate transistor, and said second transfer gate transistor is connected at its gate to a vertical address line and at its drain to a horizontal address line, so that if the vertical address line is pulled low then a reset pulse applied on the horizontal control line will not be passed to the gate of the first transistor. ### Claim 13 A device comprising: a digital image sensor comprising a pixel array and control circuitry arranged to: perform a reset operation across one row of the pixel array; integrate pixels in said row for a first calibration time; at the end of said calibration time, read pixel values of said row of pixels; compare said pixel values with one or more predetermined thresholds; and set subsequent exposure levels for pixels in the pixel array based upon said pixel values. ### Claim 14 A vehicle, comprising: a digital image sensor comprising: a pixel array; and control circuitry arranged to: perform a reset operation across one row of the pixel array; integrate pixels in said row for a first calibration time; at the end of said calibration time, read pixel values of said row of pixels; compare said pixel values with one or more predetermined thresholds; and set subsequent exposure levels for pixels in the pixel array based upon said pixel values.