# US 12,217,123 B2 · Flicker mitigation for multiple interspersed illumination systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,217,123 B2 - Document ID: US12217123B2 - Status: Granted - Kind: B2 - Application number: 18/100,304 - Filed: 2023-01-23 - Published: 2023-05-25 - Granted: 2025-02-04 - Earliest claimed: 2019-11-06 - Assignees: Zebra Technologies Corporation - Applicants: Zebra Technologies Corporation - Inventors: Przemyslaw Kowalewski; Darran Michael Handshaw; Robert W. DiGiovanna; Mark D. Anderson; Eugene B. Joseph; Mark Drzymala; Miguel Orlando Rodriguez Ortiz - Web page: https://patentgrep.com/patent/US12217123B2 ## CPC - G06K 7/10752: {Exposure time control} - G06K 7/10732: {Light sources} - G06K 7/10742: {including a diffuser for diffusing the light from the light source to create substantially uniform illumination of the target record carrier} - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract A method of activating an illumination assembly within a symbology reader is provided, the illumination assembly having a first illumination source and a second illumination source, the symbology reader having an imaging sensor configured to operate at a predetermined framerate where each frame includes an exposure period over which the imaging sensor is active to capture image data and a non-exposure period over which the imaging sensor is not active to capture image data, the method comprising: during a first frame, activating the first illumination source during at least a portion of the respective exposure period and activating the second illumination source over at least a portion of the respective non-exposure period; and during a second frame, activating the second illumination source during at least a portion of the respective exposure period and activating the first illumination source over at least a portion of the respective non-exposure period. ## Claims ### Claim 1 A method of activating an illumination assembly within a symbology reader, the illumination assembly having a first illumination source and a second illumination source, the first illumination source being configured to illuminate an illumination target with visible light, and the second illumination source being configured to illuminate the illumination target with non-visible light, the symbology reader having an imaging sensor configured to operate at a predetermined framerate where each frame includes an exposure period over which the imaging sensor is active to capture image data and a non-exposure period over which the imaging sensor is not active to capture image data, the method comprising: (a) during a first frame, activating the first illumination source during at least a portion of the respective exposure period and activating the second illumination source over at least a portion of the respective non-exposure period such that the first illumination source is not activated at the same time as the second illumination source; and (b) during a second frame, activating the second illumination source during at least a portion of the respective exposure period and activating the first illumination source over at least a portion of the respective non-exposure period such that the first illumination source is not activated at the same time as the second illumination source. ### Claim 2 (depends on 1) The method of claim 1, wherein the non-visible light is infrared light. ### Claim 3 (depends on 1) The method of claim 1, wherein the second frame immediately follows the first frame. ### Claim 4 (depends on 1) The method of claim 1, further comprising: (c) repeatedly performing (a) and (b) until the symbology reader successfully decodes a symbology captured, as the image data, by the imaging sensor. ### Claim 5 (depends on 1) The method of claim 1, wherein: (a) further includes, during the first frame, activating the first illumination source at or near a beginning of the respective exposure period; and (b) further includes, during the second frame, activating the second illumination source at or near a beginning of the respective exposure period and activating the first illumination source at or near a beginning of the respective non-exposure period. ### Claim 6 (depends on 1) The method of claim 1, wherein: (a) further includes, during the first frame, deactivating the first illumination source at or near an end of the respective exposure period; and (b) further includes, during the second frame, deactivating the second illumination source at or near an end of the respective exposure period and activating the first illumination source at or near a beginning of the respective non-exposure period. ### Claim 7 (depends on 1) The method of claim 1, wherein a duration between an activation of the first illumination source during the first frame and an activation of the first illumination source during the second frame is greater than or equal to 14 ms and less than or equal to 18 ms. ### Claim 8 (depends on 1) The method of claim 1, wherein: (a) further includes, during the first frame, deactivating the first illumination source at or near an end of the respective exposure period; and (b) further includes, during the second frame, deactivating the second illumination source at or near an end of the respective exposure period and activating the first illumination source at or near a beginning of the respective non-exposure period. ### Claim 9 An apparatus for reading symbology, comprising: a housing; an imaging sensor; an illumination assembly, the illumination assembly including a first illumination source and a second illumination source, the first illumination source being configured to illuminate an illumination target with visible light, and the second illumination source being configured to illuminate the illumination target with non-visible light; and a controller configured to: cause the imaging sensor to operate at a predetermined framerate where each frame includes an exposure period over which the imaging sensor is active to capture image data and a non-exposure period over which the imaging sensor is not active to capture image data; and (a) during a first frame, cause the first illumination source to activate over at least a portion of the respective exposure period and activating the second illumination source over at least a portion of the respective non-exposure period such that the first illumination source is not activated at the same time as the second illumination source; and (b) during a second frame, cause the second illumination source to activate over at least a portion of the respective exposure period and cause the first illumination source to activate over at least a portion of the respective non-exposure period such that the first illumination source is not activated at the same time as the second illumination source. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the non-visible light is infrared light. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein the second frame immediately follows the first frame. ### Claim 12 (depends on 9) The apparatus of claim 9, wherein the controller is further configured to: (d) repeatedly perform (a) and (b) until the symbology reader successfully decodes a symbology captured, as the image data, by the imaging sensor. ### Claim 13 (depends on 9) The apparatus of claim 9, wherein: (a) further includes, during the first frame, causing the first illumination source to activate at or near a beginning of the respective exposure period; and (b) further includes, during the second frame, causing the second illumination source to activate at or near a beginning of the respective exposure period and causing first illumination source to activate at or near a beginning of the respective non-exposure period. ### Claim 14 (depends on 9) The apparatus of claim 9, wherein: (a) further includes, during the first frame, causing the first illumination source to deactivate at or near an end of the respective exposure period; and (b) further includes, during the second frame, causing the second illumination source to deactivate at or near an end of the respective exposure period and causing the first illumination source to activate at or near a beginning of the respective non-exposure period. ### Claim 15 (depends on 9) The apparatus of claim 9, wherein a duration between an activation of the first illumination source during the first frame and an activation of the first illumination source during the second frame is greater than or equal to 14 ms and less than or equal to 18 ms. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein: (a) further includes, during the first frame, causing the first illumination source to deactivate at or near an end of the respective exposure period; (b) further includes, during the second frame, causing the second illumination source to deactivate at or near an end of the respective exposure period and causing the first illumination source to activate at or near a beginning of the respective non-exposure period. ### Claim 17 (depends on 9) The apparatus of claim 9, wherein activating the first illumination source causes an illumination target to be illuminated with diffuse light, and wherein activating the second illumination source causes the illumination target to be illuminated with direct light. ### Claim 18 (depends on 9) The apparatus of claim 9, wherein activating the first illumination source causes an illumination target to be illuminated from a right side, and wherein activating the second illumination source causes the illumination target to be illuminated from a left side.