# US 11,115,640 B2 · Multi-sensor video frame synchronization apparatus and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,640 B2 - Document ID: US11115640B2 - Status: Granted - Kind: B2 - Application number: 16/201,698 - Filed: 2018-11-27 - Published: 2019-04-18 - Granted: 2021-09-07 - Earliest claimed: 2010-12-22 - Assignees: Texas Instruments Incorporated - Applicants: Texas Instruments Incorporated - Inventors: Gregory R. Hewes; Fred W. Ware, Jr. - Web page: https://patentgrep.com/patent/US11115640B2 ## CPC - H04N 13/158: {Switching image signals} - H04N 13/167: Synchronising or controlling image signals - H04N 13/239: using two two-dimensional [2D] image sensors having a relative position equal to or related to the interocular distance (H04N13/243 takes precedence) - H04N 13/243: using three or more two-dimensional [2D] image sensors - H04N 13/296: Synchronisation thereof; Control thereof - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Apparatus and methods disclosed herein operate to monitor times of receipt of start-of-frame indications associated with frames received from multiple image sensors at a video controller. Time differences between the times of receipt of the frames are calculated. Embodiments herein alter one or more frame period determining parameter values associated with the image sensors if the time differences equal or exceed frame synchronization hysteresis threshold values. Parameter values are adjusted positively and/or negatively to decrease the time differences. The parameter values may be reset at each image sensor when the time differences become less than the frame synchronization hysteresis threshold value as additional frames are received at the video controller. ## Claims ### Claim 1 A video controller, comprising: a processor; and a non-transitory computer readable storage medium storing a program for execution by the processor, the program including instructions to: receive a first start-of-frame indication that has a first time of receipt and is associated with a first image sensor; receive a second start-of-frame indication that has a second time of receipt and is associated with a second image sensor; calculate a time difference between the first time of receipt associated with the first image sensor and the second time of receipt associated with the second image sensor; and adjust a first frame period determining parameter associated with the first image sensor to: decrease the time difference between the first time of receipt associated with the first image sensor and the second time of receipt associated with the second image sensor, in response to determining that the time difference between the first time of receipt associated with the first image sensor and the second time of receipt associated with the second image sensor is greater than or equal to a frame synchronization hysteresis threshold value; and be equal to a second frame period determining parameter of the second image sensor, in response to determining that the time difference between the first time of receipt associated with the first image sensor and the second time of receipt associated with the second image sensor is less than the frame synchronization hysteresis threshold value. ### Claim 2 (depends on 1) The video controller of claim 1, wherein the instructions further comprise instructions to adjust the second frame period determining parameter associated with the second image sensor. ### Claim 3 (depends on 1) The video controller of claim 1, further comprising instructions to adjust a horizontal blanking period of the first image sensor in response to adjusting the first frame period determining parameter of the first image sensor. ### Claim 4 (depends on 1) The video controller of claim 1, further comprising instructions to adjust a vertical blanking period of the first image sensor in response to adjusting the first frame period determining parameter of the first image sensor. ### Claim 5 (depends on 1) The video controller of claim 1, wherein the instructions to adjust the first frame period determining parameter comprise instructions to adjust an active data area of the first image sensor. ### Claim 6 (depends on 1) The video controller of claim 1, further comprising a control bus interface coupled to the processor, the control bus interface configured to transfer a control value associated with the first frame period determining parameter associated with the first image sensor to a first image sensor controller of the first image sensor. ### Claim 7 (depends on 6) The video controller of claim 6, wherein the control bus interface is an inter-integrated circuit (I2C) bus. ### Claim 8 (depends on 1) The video controller of claim 1, further comprising a video frame bus interface coupled to the processor, the video frame bus interface configured to: receive a first image frame from the first image sensor; and receive a second image frame from the second image sensor. ### Claim 9 (depends on 1) The video controller of claim 1, wherein the instructions further comprise instructions to: store a first frame associated with the first image sensor in the non-transitory computer readable storage medium; and store a second frame associated with the second image sensor in the non-transitory computer readable storage medium. ### Claim 10 (depends on 9) The video controller of claim 9, wherein the instructions to store the first frame comprise instructions to transfer the first frame to the non-transitory computer readable storage medium over a memory bus image. ### Claim 11 (depends on 1) The video controller of claim 1, further comprising the first image sensor and the second image sensor. ### Claim 12 A non-transitory computer readable storage medium storing a program for execution by a processor, the program including instructions to: receive a first time of receipt of a first start-of-frame indication associated with a first image sensor; receive a second time of receipt of a second start-of-frame indication associated with a second image sensor; calculate a time difference between the first time of receipt associated with the first image sensor and the second time of receipt associated with the second image sensor; based on the time difference between the first time of receipt and the second time of receipt being greater than or equal to a frame synchronization hysteresis threshold value, adjust a first frame period determining parameter associated with the first image sensor to an adjusted value to decrease the time difference between the first time of receipt associated with the first image sensor and the second time of receipt associated with the second image sensor; and based on the time difference between the first time of receipt and the second time of receipt being less than the frame synchronization hysteresis threshold value, adjust the first frame period determining parameter to set the first frame period determining parameter for the first image sensor to equal a second frame period determining parameter of the second image sensor. ### Claim 13 (depends on 12) The non-transitory computer readable storage medium of claim 12, wherein the instructions further comprise instructions to adjust the second frame period determining parameter associated with the second image sensor. ### Claim 14 (depends on 12) The non-transitory computer readable storage medium of claim 12, further comprising instructions to adjust a horizontal blanking period of the first image sensor in response to adjusting the first frame period determining parameter of the first image sensor. ### Claim 15 (depends on 12) The non-transitory computer readable storage medium of claim 12, further comprising instructions to adjust a vertical blanking period of the first image sensor in response to adjusting the first frame period determining parameter of the first image sensor. ### Claim 16 (depends on 12) The non-transitory computer readable storage medium of claim 12, wherein the instructions to adjust the first frame period determining parameter comprise instructions to adjust an active data area of the first image sensor. ### Claim 17 (depends on 12) The non-transitory computer readable storage medium of claim 12, wherein the instructions further comprise instructions to: store a first frame associated with the first image sensor in the non-transitory computer readable storage medium; and store a second frame associated with the second image sensor in the non-transitory computer readable storage medium. ### Claim 18 A video controller, comprising: a start-of-frame monitor configured to: receive a first start-of-frame indication that has a first time of receipt and is associated with a first image sensor; and receive a second start-of-frame indication that has a second time of receipt and is associated with a second image sensor; a frame delta calculator coupled to the start-of-frame monitor, the frame delta calculator configured to calculate a time difference between the first time of receipt and the second time of receipt; and a frame period adjuster coupled to the frame delta calculator, the frame period adjuster configured to alter a frame period determining parameter associated with at least of the first image sensor or the second image sensor from an original value to: decrease the time difference between the first time of receipt and the second time of receipt in response to determining that the time difference between the first time of receipt and the second time of receipt is greater than or equal to a frame synchronization hysteresis threshold value; and set a first frame period determining parameter for the first image sensor to equal a second frame period determining parameter of the second image sensor in response to determining that the time difference between the first time of receipt and the second time of receipt is less than the frame synchronization hysteresis threshold value. ### Claim 19 (depends on 18) The video controller of claim 18, further comprising the first image sensor and the second image sensor. ### Claim 20 (depends on 18) The video controller of claim 18, further comprising instructions to adjust a vertical blanking period of the first image sensor in response to adjusting the first frame period determining parameter of the first image sensor.