Synchronized image capture methods and apparatus
Methods and apparatus relating to controlling optical chains (OCs) of a camera device to scan a scene area of interest, thereby capturing images of the scene area, in a synchronized manner are described. In various embodiments a synchronized rolling shutter read out of two or more image sensors included in two or more corresponding OCs is implemented controlling the sensors to read out rows of pixel values corresponding to a portion of the scene at the same time, e.g., concurrently. While two or more of the OCs are controlled to read out at the same time, some other OCs in the camera maybe controlled not to read out pixel values while other image sensors are reading out. In various embodiments the read out rate of the two or more sensors corresponding to two or more optical chains is controlled as a function of the focal lengths of the corresponding OCs.
1. A method of capturing images corresponding to a scene area of interest, the method comprising:
controlling a plurality of optical chains to read out pixel values corresponding to a portion of said scene area of interest at the same time, said plurality of optical chains including a first optical chain having a first focal length and a second optical chain having a second focal length, said second focal length being different from said first focal length, different portions of said scene area of interest being read out at different times, and
wherein said controlling includes implementing synchronized rolling shutter read out of a first image sensor included in said first optical chain and a second image sensor included in the second optical chain and controlling the read out rate of said first and second image sensors as a function of the focal length of the first and second optical chains.
2. The method of claim 1 , wherein said first and second image sensors include the same number of rows of pixels.
3. The method of claim 2 , wherein a top edge of the first image sensor of the first optical chain corresponds to a row of pixel values that are read out first as part of the rolling shutter read out of said first image sensor, said rolling shutter read out including sequential reading out of rows of pixel values beginning at the top edge of the first image sensor and proceeding to a bottom edge of said first image sensor; and
wherein a top edge of the second image sensor of the second optical chain corresponds to a row of pixel values that are read out first as part of a rolling shutter read out of said second image sensor, said rolling shutter read out of the second image sensor including sequential reading out of rows of pixel values beginning at the top edge of the second image sensor and proceeding to a bottom edge of said second image sensor, the scan direction of the first and second image sensors being the same.
4. The method of claim 1 ,
wherein said first and second image sensors include the same number of pixels.
5. The method of claim 4 , wherein the first focal length of the first optical chain is larger than the second focal length of the second optical chain, the method comprising:
controlling the first image sensor to read out a number of rows of pixels in said first image sensor in a period of time which is calculated as the ratio of the second focal length to the first focal length times the amount of time used to read out the same number of rows of pixels in said second image sensor.
6. The method of claim 5 ,
wherein the first focal length is twice the second focal length; and
wherein the second image sensor is fully read out over a time period which is twice as long as a first time period used to fully read out said first image sensor.
7. The method of claim 6 ,
wherein controlling the plurality of optical chains to read out pixel values corresponding to a portion of said scene area of interest at the same time further comprises:
controlling a third image sensor of a third optical chain to read out pixel values corresponding to a third portion of said scene area of interest after a last row of pixel values is read out from said first image sensor;
wherein said first image sensor captures a first portion of said scene area of interest;
wherein said second image sensor captures a second portion of said scene area of interest which is larger than said first portion; and
wherein said third portion of said scene area of interest is positioned below said first portion of said scene area of interest.
8. The method of claim 7 ,
wherein said second image sensor captures at least substantially the same image areas as said first and third image sensors capture but during a readout time which is longer than an individual read out time of either of said first and third image sensors.
9. A camera device for capturing images corresponding to a scene area of interest, comprising:
a plurality of optical chains; and
a controller configured to control said plurality of optical chains to read out pixel values corresponding to a portion of said scene area of interest at the same time, said plurality of optical chains including a first optical chain having a first focal length and a second optical chain having a second focal length, said second focal length being different from said first focal length, different portions of said scene area of interest being read out at different times, said controller being further configured to implement synchronized rolling shutter read out of a first image sensor included in said first optical chain and a second image sensor included in the second optical chain and control the read out rate of said first and second image sensors as a function of the focal length of the first and second optical chains, as part of being configured to control said plurality of optical chains to read out pixel values corresponding to a portion of said scene area of interest at the same time.
10. The camera device of claim 9 , wherein said first and second image sensors include the same number of rows of pixels.
11. The camera device of claim 10 , wherein a top edge of the first image sensor of the first optical chain corresponds to a row of pixel values that are read out first as part of the rolling shutter read out of said first image sensor, said rolling shutter read out including sequential reading out of rows of pixel values beginning at the top edge of the first image sensor and proceeding to a bottom edge of said first image sensor; and
wherein a top edge of the second image sensor of the second optical chain corresponds to a row of pixel values that are read out first as part of a rolling shutter read out of said second image sensor, said rolling shutter read out of the second image sensor including sequential reading out of rows of pixel values beginning at the top edge of the second image sensor and proceeding to a bottom edge of said second image sensor, the scan direction of the first and second image sensors being the same.
12. The camera device of claim 9 ,
wherein said first and second image sensors include the same number of pixels.
13. The camera device of claim 12 , wherein the first focal length is larger than the second focal length; and
wherein said controller is further configured to control the first image sensor to read out a number of rows of pixels in said first image sensor in a period of time which is calculated as the ratio of the second focal length to the first focal length times the amount of time used to read out the same number of rows of pixels in said second image sensor.
14. The camera device of claim 13 ,
wherein the first focal length is twice the second focal length; and
wherein the controller is further configured to control the second image sensor to be fully read out over a time period which is twice as long as a first time period used to fully read out said first image sensor.
15. The camera device of claim 14 ,
wherein said first image sensor captures a first portion of said scene area of interest;
wherein said second image sensor captures a second portion of said scene area of interest which is larger than said first portion; and
wherein said controller is further configured to control a third image sensor of a third optical chain to read out pixel values corresponding to a third portion of said scene area of interest after a last row of pixel values is read out from said first image sensor, said third portion of said scene area of interest being positioned below said first portion of said scene area of interest.
16. The camera device of claim 15 ,
wherein said second image sensor captures at least substantially the same image area as said first and third image sensors capture but during a readout time which is longer than an individual read out time of either of said first and third image sensors.
17. A non-transitory computer readable medium comprising computer executable instructions, said non-transitory computer readable medium comprising:
instructions, which when executed by a processor, control a plurality of optical chains to read out pixel values corresponding to a portion of said scene area of interest at the same time, said plurality of optical chains including a first optical chain having a first focal length and a second optical chain having a second focal length, said second focal length being different from said first focal length, different portions of said scene area of interest being read out at different times; and
wherein said instructions, which when executed by said processor, control said plurality of optical chains to read out pixel values corresponding to a portion of said scene area of interest at the same time, include instructions for implementing synchronized rolling shutter read out of a first image sensor included in said first optical chain and a second image sensor included in the second optical chain and controlling the read out rate of said first and second image sensors as a function of the focal length of the first and second optical chains.
18. The non-transitory computer readable medium of claim 17 ,
wherein said first and second image sensors include the same number of rows of pixels.