Imaging device 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 for detecting light passing through the condensing lens and comprising a pixel matrix, wherein the pixel matrix comprises a plurality of phase detection pixel pairs and a plurality of regular pixels; and
a processor for
turning on the phase detection pixel pairs for autofocusing and outputting autofocused pixel data after completing the autofocusing;
dividing the autofocused pixel data into a first subframe and a second subframe;
calculating image features of at least one of the first subframe and the second subframe, wherein the image features comprise module widths of a finder pattern, and the finder pattern has a predetermined ratio, a Harr-like feature, or a Gabor feature; and
determining an operating resolution of the regular pixels according to the image features calculated from at least one of the first subframe and the second subframe divided from the autofocused pixel data;
wherein the phase detection pixel pairs are always on when the imaging device is powered on, and pixel data of the regular pixels is not used in 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 mirror symmetrical to each other; 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 pixel data of the phase detection pixel pairs before the autofocusing is accomplished.
5. The imaging device as claimed in claim 1 , wherein the processor is configured to
divide pixel data of the phase detection pixel pairs into a third subframe and a fourth subframe before the autofocusing is accomplished; 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 operating resolution is selected as a first resolution smaller than a number of the regular pixels or as a second resolution larger than the first resolution.
8. The imaging device as claimed in claim 1 , wherein the regular pixels are turned off in the autofocusing.
9. The imaging device as claimed in claim 1 , wherein a number of the phase detection pixel pairs is smaller than that of the regular pixels.
10. An imaging device comprising:
a condensing lens;
an image sensor for detecting light passing through the condensing lens and comprising a pixel matrix, wherein the pixel matrix comprises a plurality of phase detection pixel pairs and a plurality of regular pixels; and
a processor configured for
turning on the phase detection pixel pairs for autofocusing and outputting autofocused pixel data after the completing the autofocusing;
dividing the autofocused pixel data into a first subframe and a second subframe;
calculating image features of at least one of the first subframe and the second subframe, wherein the image features comprise module widths of a finder pattern, and the finder pattern has a predetermined ratio, a Harr-like feature, or a Gabor feature; and
selecting an image decoding or an image recognition using pixel data of the regular pixels according to the image features calculated from at least one of the first subframe and the second subframe divided from the autofocused pixel data;
wherein the phase detection pixel pairs are always on when the imaging device is powered on, and the regular pixels are selectively activated for the image decoding or the image recognition.
11. The imaging device as claimed in claim 10 , 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 mirror symmetrical to each other; and
a microlens aligned with at least one of the first pixel and the second pixel.
12. The imaging device as claimed in claim 10 , wherein the processor is configured to perform the autofocusing using a dual pixel autofocus technique according to pixel data of the phase detection pixel pairs before the autofocusing is accomplished.
13. The imaging device as claimed in claim 10 , wherein the processor is configured to
divide the pixel data of the phase detection pixel pairs into a third subframe and a fourth subframe before the autofocusing is accomplished;
calibrate brightness of the third subframe and the fourth subframe to be identical using a shading algorithm; and
perform the autofocusing according to the third subframe and the fourth subframe.
14. The imaging device as claimed in claim 10 , wherein the processor is configured to calculate the image features using at least one of a rule based algorithm and a machine learning algorithm.
15. The imaging device as claimed in claim 10 , wherein the image decoding is decoding QR codes, and the image recognition is face recognition.
16. 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 for autofocusing and outputting autofocused image frame after completing the autofocusing;
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, wherein the image feature comprise module widths of a finder pattern, and the finder pattern has a predetermined ratio, a Harr-like feature, or a Gabor feature; and
selectively activating at least a part of the regular pixels according to the image features calculated from at least one of the first subframe and the second subframe divided from the autofocused image frame;
wherein the phase detection pixel pairs are continuously turned on when the at least a part of the regular pixels are activated, and the regular pixels are not activated in the autofocusing.
17. The operating method as claimed in claim 16 , wherein the selectively activating comprises:
activating 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
activating all the regular pixels to perform an image recognition according to pixel data of the all regular pixels.
18. The operating method as claimed in claim 17 , 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.
19. The operating method as claimed in claim 17 , wherein the image decoding is decoding QR codes, and the image recognition is face recognition.
20. The operating method as claimed in claim 16 , wherein the phase detection pixel pairs are partially covered pixels or have a structure of dual pixel.