# US 2019/0320102 A1 · Power reduction for dual camera synchronization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0320102 A1 - Document ID: US20190320102A1 - Status: Published application - Kind: A1 - Application number: 15/952,936 - Filed: 2018-04-13 - Published: 2019-10-17 - Earliest claimed: 2018-04-13 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Tanvi Aggarwal; Vijay Kumar Tumati; Ajay Kumar Dhiman - Web page: https://patentgrep.com/patent/US20190320102A1 ## CPC - H04N 23/45: for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images - H04N 5/2621: {Cameras specially adapted for the electronic generation of special effects during image pickup, e.g. digital cameras, camcorders, video cameras having integrated special effects capability} - H04N 23/60: Control of cameras or camera modules - H04N 23/617: Upgrading or updating of programs or applications for camera control - H04N 23/65: Control of camera operation in relation to power supply - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Methods and apparatuses are disclosed for reducing power consumption in image processing systems comprising a master image sensor and a slave image sensor synchronized to the master image sensor. For example, a synchronization signal may be periodically sent from the master image sensor to the slave image sensor, where the synchronization signal is sent once per synchronization period and indicates a frame start time. A time may be estimated to complete an image processing operation. A comparison may be made between the estimated time and the synchronization period, and a frame capture rate of the slave image sensor may be selectively adjusted based at least in part on the comparison. ## Claims ### Claim 1 A method for image capture, comprising: periodically sending a synchronization signal from a master image sensor of a multiple camera module to a slave image sensor of the multiple camera module, the synchronization signal sent once per synchronization period and indicating a frame start time; estimating a time required to complete an image processing operation; comparing the estimated time to the synchronization period; and selectively adjusting a frame update rate of the slave image sensor based at least in part on the comparing. ### Claim 2 (depends on 1) The method of claim 1, wherein the image processing operation is a determination of a depth map indicating proximities of objects in a scene captured by the master and the slave image sensors. ### Claim 3 (depends on 1) The method of claim 1, further comprising determining that the image processing operation has completed, and instructing the slave image sensor to cease selectively ignoring synchronization signals. ### Claim 4 (depends on 1) The method of claim 1, wherein selectively adjusting the frame update rate of the slave image sensor comprises, at the slave image sensor: receiving a first synchronization signal indicating a frame start time for a first frame to be captured by the slave image sensor; ignoring a number of subsequently received synchronization signals; and receiving a second synchronization signal indicating a frame start time for a second frame to be captured by the slave image sensor. ### Claim 5 (depends on 4) The method of claim 4, wherein the number of ignored synchronization signals is based at least in part on a ratio between the estimated time and the synchronization period. ### Claim 6 (depends on 4) The method of claim 4, wherein selectively ignoring one or more synchronization signals comprises ignoring every other synchronization signal received from the master image sensor. ### Claim 7 (depends on 1) The method of claim 1, wherein the synchronization signal indicates a clock edge corresponding to the frame start time. ### Claim 8 (depends on 1) The method of claim 1, wherein selectively adjusting the frame update rate of the slave image sensor comprises, at the master image sensor: transmitting a first synchronization signal indicating a frame start time for a first frame to be captured by the slave image sensor; refraining from transmission of a number of subsequent synchronization signals; and transmitting a second synchronization signal indicating a frame start time for a second frame to be captured by the slave image sensor. ### Claim 9 (depends on 8) The method of claim 8, wherein the master image sensor refrains from transmission of a number of synchronization signals which is based at least in part on a ratio between the estimated time and the synchronization period. ### Claim 10 (depends on 8) The method of claim 8, wherein the master image sensor refrains from transmission of every other synchronization signal. ### Claim 11 An image processing device, comprising: two or more image sensors, comprising a master image sensor and a slave image sensor synchronized to the master image sensor; one or more processors; and a memory, coupled to the two or more image sensors and to the one or more processors, storing instructions that, when executed by the one or more processors, cause the image processing device to: periodically send a synchronization signal from the master image sensor to the slave image sensor, the synchronization signal sent once per synchronization period and indicating a frame start time; estimate a time required to complete an image processing operation; compare the estimated time to the synchronization period; and selectively adjust a frame update rate of the slave image sensor based at least in part on the comparing. ### Claim 12 (depends on 11) The image processing device of claim 11, wherein the image processing operation is a determination of a depth map indicating proximities of objects in a scene captured by the master and the slave image sensors. ### Claim 13 (depends on 11) The image processing device of claim 11, wherein execution of the instructions further causes the image processing device to determine that the image processing operation has completed, and instruct the slave image sensor to cease selectively ignoring synchronization signals. ### Claim 14 (depends on 11) The image processing device of claim 11, wherein execution of the instructions to selectively adjust the frame update rate of the slave image sensor further causes the image processing device to, at the slave image sensor: receive a first synchronization signal indicating a frame start time for a first frame to be captured by the slave image sensor; ignore a number of subsequently received synchronization signals; and receive a second synchronization signal indicating a frame start time for a second frame to be captured by the slave image sensor. ### Claim 15 (depends on 14) The image processing device of claim 14, wherein the number of ignored synchronization signals is based at least in part on a ratio between the estimated time and the synchronization period. ### Claim 16 (depends on 14) The image processing device of claim 14, wherein selectively ignoring one or more synchronization signals comprises ignoring every other synchronization signal received from the master image sensor. ### Claim 17 (depends on 11) The image processing device of claim 11, wherein the synchronization signal indicates a clock edge corresponding to the frame start time. ### Claim 18 (depends on 11) The image processing device of claim 11, wherein execution of the instructions to selectively adjust the frame update rate of the slave image sensor further causes the image processing device to, at the master image sensor: transmit a first synchronization signal indicating a frame start time for a first frame to be captured by the slave image sensor; refraining from transmission of a number of subsequent synchronization signals; and transmitting a second synchronization signal indicating a frame start time for a second frame to be captured by the slave image sensor. ### Claim 19 (depends on 18) The image processing device of claim 18, wherein the master image sensor refrains from transmission of a number of synchronization signals which is based at least in part on a ratio between the estimated time and the synchronization period. ### Claim 20 (depends on 18) The image processing device of claim 18, wherein the master image sensor refrains from transmission of every other synchronization signal. ### Claim 21 A non-transitory computer-readable storage medium storing instructions that, when executed by one or more processors of an image processing device, cause the image processing device to: periodically send a synchronization signal from a master image sensor to a slave image sensor synchronized to the master image sensor, the synchronization signal sent once per synchronization period and indicating a frame start time; estimate a time required to complete an image processing operation; compare the estimated time to the synchronization period; and selectively adjust a frame update rate of the slave image sensor based at least in part on the comparing. ### Claim 22 (depends on 21) The non-transitory computer-readable storage medium of claim 21, wherein the image processing operation is a determination of a depth map indicating proximities of objects in a scene captured by the master and the slave image sensors. ### Claim 23 (depends on 21) The non-transitory computer-readable storage medium of claim 21, wherein execution of the instructions further causes the image processing device to determine that the image processing operation has completed, and instruct the slave image sensor to cease selectively ignoring synchronization signals. ### Claim 24 (depends on 21) The non-transitory computer-readable storage medium of claim 21, wherein execution of the instructions to selectively adjust the frame update rate of the slave image sensor further causes the image processing device to, at the slave image sensor: receive a first synchronization signal indicating a frame start time for a first frame to be captured by the slave image sensor; ignore a number of subsequently received synchronization signals; and receive a second synchronization signal indicating a frame start time for a second frame to be captured by the slave image sensor. ### Claim 25 (depends on 24) The non-transitory computer-readable storage medium of claim 24, wherein the number of ignored synchronization signals is based at least in part on a ratio between the estimated time and the synchronization period. ### Claim 26 (depends on 24) The non-transitory computer-readable storage medium of claim 24, wherein selectively ignoring one or more synchronization signals comprises ignoring every other synchronization signal received from the master image sensor. ### Claim 27 (depends on 21) The non-transitory computer-readable storage medium of claim 21, wherein the synchronization signal indicates a clock edge corresponding to the frame start time. ### Claim 28 (depends on 21) The non-transitory computer-readable storage medium of claim 21, wherein execution of the instructions to selectively adjust the frame update rate of the slave image sensor further causes the image processing device to, at the master image sensor: transmit a first synchronization signal indicating a frame start time for a first frame to be captured by the slave image sensor; refraining from transmission of a number of subsequent synchronization signals; and transmitting a second synchronization signal indicating a frame start time for a second frame to be captured by the slave image sensor. ### Claim 29 (depends on 28) The non-transitory computer-readable storage medium of claim 28, wherein the master image sensor refrains from transmission of a number of synchronization signals which is based at least in part on a ratio between the estimated time and the synchronization period. ### Claim 30 An image processing device, comprising means for periodically sending a synchronization signal from a master image sensor to a slave image sensor synchronized to the master image sensor, the synchronization signal sent once per synchronization period and indicating a frame start time; means for estimating a time required to complete an image processing operation; means for comparing the estimated time to the synchronization period; and means for selectively adjusting a frame update rate of the slave image sensor based at least in part on the comparing.