Imaging device having phase detection pixels and regular pixels, and operating method thereof
An imaging device including a pixel matrix and a processor is provided. The pixel matrix includes a plurality of phase detection pixels and a plurality of regular pixels. The processor performs autofocusing according to pixel data of the phase detection pixels, and determines an operating resolution of the regular pixels according to autofocused pixel data of the phase detection pixels, wherein the phase detection pixels are always-on pixels and the regular pixels are selectively turned on after the autofocusing is accomplished.
1. An imaging device, comprising:
a condensing lens;
an image sensor configured to detect light passing through the condensing lens to generate an image frame and comprising a pixel matrix, the pixel matrix comprising a plurality of phase detection pixel pairs and a plurality of regular pixels; and
a processor configured to
perform autofocusing according to pixel data of the phase detection pixel pairs,
divide autofocused pixel data, which is acquired by the phase detection pixel pairs without turning on the regular pixels yet after the autofocusing, into a first subframe and a second subframe,
calculate image features of at least one of the first subframe and the second subframe, and
determine an operating resolution as a first resolution or a second resolution according to the calculated image features,
wherein the phase detection pixel pairs are always on, and the regular pixels are selectively turned on after the autofocusing.
2. The imaging device as claimed in claim 1 , wherein each of the phase detection pixel pairs comprises:
a first pixel and a second pixel;
a cover layer covering upon a first region of the first pixel and upon a second region of the second pixel, wherein the first region and the second region are rectangles of mirror symmetry; and
a microlens aligned with at least one of the first pixel and the second pixel.
3. The imaging device as claimed in claim 2 , wherein the first region and the second region are 5% to 95% of an area of a single pixel.
4. The imaging device as claimed in claim 1 , wherein the processor is configured to perform the autofocusing using a dual pixel autofocus technique according to the pixel data of the phase detection pixel pairs.
5. The imaging device as claimed in claim 1 , wherein the processor is configured to
divide the pixel data of the phase detection pixel pairs into a third subframe and a fourth subframe; and
perform the autofocusing according to the third subframe and the fourth subframe.
6. The imaging device as claimed in claim 5 , wherein the processor is further configured to calibrate brightness of the third subframe and the fourth subframe to be identical using a shading algorithm.
7. The imaging device as claimed in claim 1 , wherein the first resolution is smaller than a number of the regular pixels, and the second resolution is equal to the number of the regular pixels.
8. An imaging device, comprising:
a condensing lens;
an image sensor configured to detect light passing through the condensing lens to generate an image frame and comprising a pixel matrix, the pixel matrix comprising a plurality of phase detection pixel pairs and a plurality of regular pixels; and
a processor configured to
perform autofocusing according to pixel data of the phase detection pixel pairs,
divide autofocused pixel data, which is acquired by the phase detection pixel pairs, without turning on the regular pixels yet after the autofocusing, into a first subframe and a second subframe,
calculate image features of at least one of the first subframe and the second subframe using at least one of a rule based algorithm and a machine learning algorithm, and
select an image decoding or an image recognition using pixel data of the regular pixels according to the calculated image features of the autofocused pixel data of the phase detection pixel pairs,
wherein the phase detection pixel pairs are always on, and the regular pixels are selectively turned on after the image decoding or the image recognition is selected.
9. The imaging device as claimed in claim 8 , wherein each of the phase detection pixel pairs comprises:
a first pixel and a second pixel;
a cover layer covering upon a first region of the first pixel and upon a second region of the second pixel, wherein the first region and the second region are rectangles of mirror symmetry; and
a microlens aligned with at least one of the first pixel and the second pixel.
10. The imaging device as claimed in claim 8 , wherein the processor is configured to perform the autofocusing using a dual pixel autofocus technique according to the pixel data of the phase detection pixel pairs.
11. The imaging device as claimed in claim 8 , wherein the processor is configured to
divide the pixel data of the phase detection pixel pairs into a third subframe and a fourth subframe; and
perform the autofocusing according to the third subframe and the fourth subframe.
12. The imaging device as claimed in claim 11 , wherein the processor is further configured to calibrate brightness of the third subframe and the fourth subframe to be identical using a shading algorithm.
13. The imaging device as claimed in claim 8 , wherein the image decoding is decoding QR codes, and the image recognition is a face recognition.
14. An operating method of an imaging device, the imaging device comprising a plurality of phase detection pixel pairs and a plurality of regular pixels, the operating method comprising:
turning on the phase detection pixel pairs and turning off the regular pixels;
acquiring an image frame by the phase detection pixel pairs;
performing autofocusing according to the image frame;
acquiring an autofocused image frame by the phase detection pixel pairs without turning on the regular pixels yet;
dividing the autofocused image frame, acquired by the phase detection pixel pairs, into a first subframe and a second subframe;
calculating image features of at least one of the first subframe and the second subframe using at least one of a rule based algorithm and a machine learning algorithm; and
selectively turning on at least a part of the regular pixels according to the calculated image features of the autofocused image frame.
15. The operating method as claimed in claim 14 , wherein the selectively turning on comprises
turning on a first part of the regular pixels to perform an image decoding according to pixel data of the first part of the regular pixels; or
turning on all the regular pixels to perform an image recognition according to pixel data of the all regular pixels.
16. The operating method as claimed in claim 15 , wherein pixel data of the phase detection pixel pairs captured in a same frame with the pixel data of the regular pixels is also used in performing the image decoding and the image recognition.
17. The operating method as claimed in claim 15 , wherein the image decoding is decoding QR codes, and the image recognition is a face recognition.
18. The operating method as claimed in claim 14 , wherein the phase detection pixel pairs are partially covered pixels or have a structure of dual pixel.