# US 11,445,133 B2 · Low power and low data-rate imager > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,445,133 B2 - Document ID: US11445133B2 - Status: Granted - Kind: B2 - Application number: 16/632,103 - Filed: 2018-08-09 - Published: 2020-05-28 - Granted: 2022-09-13 - Earliest claimed: 2017-08-10 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Vladimir Petkov; Pedram Lajevardi; Christoph Lang; Nikhil Naikal; Sam Kavusi - Web page: https://patentgrep.com/patent/US11445133B2 ## CPC - G06F 1/3265: {Power saving in display device} - H04N 25/42: by switching between different modes of operation using different resolutions or aspect ratios, e.g. switching between interlaced and non-interlaced mode - H04N 25/445: by skipping some contiguous pixels within the read portion of the array - H04N 25/50: Control of the SSIS exposure - H04N 25/707: Pixels for event detection - H04N 25/78: Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters - Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract An imaging system for low-power and low data-rate applications is provided. The imaging system comprises a pixel array having a plurality of photosensitive elements (pixels) divided into a plurality of groups of photosensitive elements (super pixels). An image processor is operably connected to the pixel array and configured to selectively operate each group of photosensitive elements in either (i) a high resolution mode in which the pixel array outputs readout voltages corresponding to all of the photosensitive elements in the respective group of photosensitive elements or (ii) a low resolution mode in which the pixel array outputs readout voltages corresponding to only a subset of the photosensitive elements in the respective group of photosensitive elements. Groups of photosensitive elements corresponding to detected motion in each image frame are operated in the high resolution mode, while the remaining groups of photosensitive elements are operated in the low resolution mode. ## Claims ### Claim 1 An imaging system comprising: a pixel array having a plurality of photosensitive elements arranged in a grid formation and being divided into a plurality of groups of photosensitive elements, the photosensitive elements in each group of photosensitive elements being adjacent to one another in the grid formation, the pixel array being configured to output readout voltages proportional to light intensities at individual photosensitive elements in the plurality of photosensitive elements; an analog-to-digital converter operably connected to the pixel array to receive the readout voltages and convert the readout voltages into digitized light intensity values; and at least one processor operably connected to the pixel array and the analog-to-digital converter, the at least one processor being configured to selectively operate each group of photosensitive elements in the plurality of groups of photosensitive elements in one of (i) a high resolution mode in which the pixel array outputs readout voltages corresponding to all of the photosensitive elements in the respective group of photosensitive elements and (ii) a low resolution mode in which the pixel array outputs readout voltages corresponding to only a subset of the photosensitive elements in the respective group of photosensitive elements, wherein each group of photosensitive elements in the plurality of groups of photosensitive elements is operable by the at least one processor in both the high resolution mode and the low resolution mode at different times wherein the at least one processor is configured to: for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the low resolution mode, control the analog-to-digital converter to convert the readout voltages corresponding to the respective the subset of the photosensitive elements in the respective group of photosensitive elements with a first bit depth that is less than a maximum bit depth of the analog-to-digital converter; and for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the high resolution mode, control the analog-to-digital converter to convert the readout voltages corresponding to all of the photosensitive elements in the respective group of photosensitive elements with the maximum bit depth of the analog-to-digital converter. ### Claim 2 (depends on 1) The imaging system of claim 1, the at least one processor being configured to: receive an image frame, from the analog-to-digital converter, comprising digitized light intensity values corresponding to at least some of the photosensitive elements in each group of photosensitive elements in the plurality of groups of photosensitive elements; and selectively operate each group of photosensitive elements in the plurality of groups of photosensitive elements in the high resolution mode and the low resolution mode at different times depending on the digitized light intensity values of the image frame. ### Claim 3 (depends on 2) The imaging system of claim 2, the at least one processor being configured to: operate a first group of photosensitive elements in the plurality of groups of photosensitive elements in the low resolution mode depending on to the digitized light intensity values in the image frame corresponding to the photosensitive elements in the first group of photosensitive elements; and operate a second group of photosensitive elements in the plurality of groups of photosensitive elements in the high resolution mode depending on to the digitized light intensity values in the image frame corresponding to the photosensitive elements in the second group of photosensitive elements. ### Claim 4 (depends on 2) The imaging system of claim 2, the at least one processor being configured to, for each group of photosensitive elements in the plurality of groups of photosensitive elements: detect whether any moving objects are present in a respective portion of the image frame corresponding to the respective group of photosensitive elements based on the digitized light intensity values in the image frame corresponding to the photosensitive elements in the respective group of photosensitive elements; operate the respective group of photosensitive elements in the low resolution mode in response to no moving object being detected in the respective portion of the image frame corresponding to the respective group of photosensitive elements; and operate the respective group of photosensitive elements in the high resolution mode in response to a moving object being detected in the respective portion of the image frame corresponding to the respective group of photosensitive elements. ### Claim 5 (depends on 4) The imaging system of claim 4, the at least one processor being configured to, for each group of photosensitive elements in the plurality of groups of photosensitive elements: compare the respective portion of the image frame corresponding to the respective group of photosensitive elements with a corresponding portion of a reference background image frame to detect whether any moving objects are present in the respective portion of the image frame. ### Claim 6 (depends on 5) The imaging system of claim 5, the at least one processor being configured to: generate an intermediate image frame comprising light intensity difference values by subtracting the reference background image frame from the received image frame. ### Claim 7 (depends on 6) The imaging system of claim 6, the at least one processor being configured to, for each group of photosensitive elements in the plurality of groups of photosensitive elements: operate the respective group of photosensitive elements in the low resolution mode in response to the absolute value of each light intensity difference value of a respective portion of the intermediate image frame that corresponds to the respective group of photosensitive elements being less than a predetermined threshold difference value; and operate the respective group of photosensitive elements in the high resolution mode in response to the absolute value of any light intensity difference value of a respective portion of the intermediate image frame that corresponds to the respective group of photosensitive elements being greater than a predetermined threshold difference value. ### Claim 8 (depends on 5) The imaging system of claim 5, the at least one processor being configured to: detect a change of lighting conditions in the image frame based on the digitized light intensity values of the image frame; and operate the pixel array with an adjusted exposure time that depends on the change in the lighting conditions. ### Claim 9 (depends on 6) The imaging system of claim 6, the at least one processor being configured to: identify at least one portion of the reference background image frame to be updated based on the intermediate image frame, the at least one portion corresponding to at least one group of photosensitive elements in the plurality of groups of photosensitive elements; and update the at least one portion of the reference background image frame based on at least one corresponding portion of the image frame. ### Claim 10 (depends on 1) The imaging system of claim 1, wherein: each group of photosensitive elements in the plurality of groups of photosensitive elements comprises a common number of photosensitive elements arranged in a common formation within the grid formation; and for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the low resolution mode, the subset of the photosensitive elements for which the pixel array outputs readout voltages corresponds to a defined pattern of photosensitive elements within the common formation. ### Claim 11 (depends on 10) The imaging system of claim 10, wherein the defined pattern of photosensitive elements within the common formation is adjustable by the at least one processor. ### Claim 12 (depends on 1) The imaging system of claim 1, wherein the first bit depth is adjustable by the at least one processor. ### Claim 13 (depends on 1) The image system of claim 1, the at least one processor being configured to: for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the low resolution mode, control the pixel array and the analog-to-digital converter to update and convert the readout voltages corresponding to the subset of the photosensitive elements in the respective group of photosensitive elements with a first update rate that is less than a maximum update rate; and for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the high resolution mode, control the pixel array and the analog-to-digital converter to update and convert the readout voltages corresponding to all of the photosensitive elements in the respective group of photosensitive elements with the maximum update rate. ### Claim 14 (depends on 13) The imaging system of claim 13, wherein the first update rate is adjustable by the at least one processor. ### Claim 15 An imaging system comprising: a pixel array having a plurality of photosensitive elements arranged in a grid formation and being divided into a plurality of groups of photosensitive elements, the photosensitive elements in each group of photosensitive elements being adjacent to one another in the grid formation, the pixel array being configured to output readout voltages proportional to light intensities at individual photosensitive elements in the plurality of photosensitive elements; an analog-to-digital converter operably connected to the pixel array to receive the readout voltages and convert the readout voltages into digitized light intensity values; and at least one processor operably connected to the pixel array and the analog-to-digital converter, the at least one processor being configured to selectively operate each group of photosensitive elements in the plurality of groups of photosensitive elements in one of (i) a high resolution mode in which the pixel array outputs readout voltages corresponding to all of the photosensitive elements in the respective group of photosensitive elements and (ii) a low resolution mode in which the pixel array outputs readout voltages corresponding to only a subset of the photosensitive elements in the respective group of photosensitive elements, wherein each group of photosensitive elements in the plurality of groups of photosensitive elements is operable by the at least one processor in both the high resolution mode and the low resolution mode at different times, and wherein the at least one processor is further configured to: for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the low resolution mode, control the pixel array and the analog-to-digital converter to update and convert the readout voltages corresponding to the subset of the photosensitive elements in the respective group of photosensitive elements with a first update rate that is less than a maximum update rate; and for each group of photosensitive elements in the plurality of groups of photosensitive elements that is operated in the high resolution mode, control the pixel array and the analog-to-digital converter to update and convert the readout voltages corresponding to all of the photosensitive elements in the respective group of photosensitive elements with the maximum update rate.