3D imaging using phase detection autofocus (PDAF) image sensor

Patent metadata

Field	Value
Publication number	US-10996426-B2
Application number	US-201916546358-A
Country	US
Kind code	B2
Filing date	Aug 21, 2019
Priority date	Aug 21, 2019
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A 3D imaging system comprises a phase detection autofocus (PDAF) image sensor, a lens for imaging a cross-section of a 3D object on the PDAF image sensor and an actuator for driving the lens for focusing each cross-section of the 3D object on the PDAF image sensor. The actuator drives the lens until the PDAF image sensor identifies an image of a first cross-section of the 3D object in-focus and records the image of the first cross-section. The PDAF image sensor records images of subsequent cross-sections of the 3D object formed by the lens driven by the actuator on the PDAF image sensor. The recorded images of each cross-section of the 3D object are stacked to form a 3D image of the 3D object.

First claim

What is claimed is:

1. A 3D imaging system comprising:
a phase detection autofocus (PDAF) image sensor;
a lens for imaging a cross-section of a 3D object on the phase detection autofocus (PDAF) image sensor;
an actuator for driving the lens for imaging each cross-section of the 3D object on the PDAF image sensor;
wherein the actuator drives the lens until the PDAF image sensor identifies an image of a first cross-section of the 3D object in-focus and records the image of the first cross-section;
wherein the PDAF image sensor records images of subsequent cross-sections of the 3D object formed by the lens driven by the actuator on the PDA F image sensor;
wherein the recorded images of cross-sections of the 3D object are stacked to form a 3D image of the 3D object;
wherein prior to the recorded images of cross-sections of the 3D object being stacked to form the 3D image of the 3D object, the recorded images are digitally processed by one of deblurring using unsharp masking and deconvolution of the recorded images with a vertical point spread function.

2. The system of claim 1 , wherein the subsequent cross-sections of the 3D object comprising one of cross-sections closer to the lens from the first cross-section and cross-sections further away from the lens from the first cross-section.

3. The system of claim 1 , wherein the PDAF image sensor comprises PDAF right-image pixels for capturing a right image and left-image pixels for capturing a left image, wherein the right image is the image formed by light through a right half of the lens, and the left image is the image formed by light through a left half of the lens.

4. The system of claim 3 , wherein the PDAF right-image pixel is a pixel having a microlens, a photodiode, and a left mask blocking incident light of the left image and allowing incident light of the right image entering the photodiode, and the PDAF left-image pixel is a pixel having a microlens, a photodiode, and a right mask blocking incident light of the right image and allowing incident light of the left image entering the photodiode.

5. The system of claim 4 , wherein the PDAF identifies the image of the first cross-section of the 3D object in-focus based on overlapping of the right image and the left image.

6. The system of claim 1 , wherein the PDAF image sensor comprises PDAF pixels, each PDAF pixel has a micro lens, and separated right and left photodiodes, the right photodiodes for capturing a right image and the left photodiodes for capturing a left image,
wherein the right image is the image formed by light through a right half of the lens, and the left image is the image formed by light through a left half of the lens.

7. The system of claim 6 , wherein the PDAF image sensor identifies the image of the first cross-section of the 3D object in-focus if the right photo diode and the left photodiode of the PDAF pixel have a same value.

8. The system of claim 6 , wherein at least two identical PDAF pixels are immediately next to each other.

9. A 3D imaging system comprising:
a phase detection autofocus (PDAF) image sensor;
wherein the PDAF image sensor comprises PDAF right-image pixels for capturing a right image and left-image pixels for capturing a loft image, wherein the right image is the image formed by light through a right half of the lens, and the left image is the image formed by light through a left half of the lens:
a lens for imaging a cross-section of a 3D object on the PDAF image sensor;
an actuator for driving the lens for imaging each cross-section of the 3D object on the PDAF image sensor;
wherein the actuator drives the lens until the PDAF image sensor identifies an image of a first cross-section of the 3D object in-focus and records the image of the first cross-section;
wherein the PDAF identifies the image of the first cross-section of the 3D object in-focus based on overlapping of the right image and the left image;
wherein the PDAF image sensor records images of subsequent cross-sections of the 3D object formed by the lens driven by the actuator on, the PDAF image sensor;
wherein the recorded images of cross-sections of the 3D object are stacked to form a 3D image of the 3D object; and
wherein a distance between two subsequent cross-sections is determined by one of a cloth of focus and a numerical aperture of the lens.

10. The system of claim 9 , wherein the PDAF right-image pixel is a pixel having a microlens, a photodiode, and a left mask blocking incident light of the left image and allowing incident light of the right image entering the photodiode, and the PDAF left-image pixel is a pixel having a microlens, a photodiode, and a right mask blocking incident light of the right image and allowing incident light of the left image entering the photodiode.

11. The system of claim 9 , wherein the subsequent cross-sections of the 3D object comprising one of cross-sections closer to the lens from the first cross-section and cross-sections further away from the lens from the first cross-section.

12. The system of claim 9 , wherein the PDAF right-image pixel and left-image pixel are included in a pair of pixels, which is covered by a single microlens.

13. The system of claim 9 , wherein the PDAF right-image pixel and left-image pixel are included in a group of four pixels, which is covered by a single microlens.

14. The system of claim 9 , wherein prior to the recorded images of cross-sections of the 3D object being stacked to form the 3D image of the 3D object, the recorded images are digitally processed by one of deblurring using unsharp masking and deconvolution of the recorded images with a vertical point read function.

15. A 3D imaging system comprising:
a phase detection autofocus (PDAF) image sensor, wherein the PDAF image sensor comprises PDAF pixels, each PDAF pixel has a microlens, and separated right and left photodiodes, right photodiodes for capturing a right image and left photodiodes for capturing a left image, wherein the right image is the image formed by light through a right half of the lens, and the left image is the image formed by light through a left half of the lens;
a lens for imaging a cross-section of a 3D object on the PDAF image sensor;
an actuator for driving the lens for imaging subsequent cross-sections of the 3D object on the PDAF image sensor;
wherein the PDAF image sensor records values of PDAF pixels of an image of each cross-section, if the right photo diode and the left photodiode of the PDAF pixel have a same value, forming a recorded image of each cross-section;
wherein the recorded images of the subsequent cross-sections of the 3D object are stacked to form a 3D image of the 3D object.

16. The system of claim 15 , wherein the PDAF image sensor does not, record a value of a PDAF pixel of an image of a cross-section, if a right photo diode and a left photo diode of the PDAF pixel have different values.

17. The system of claim 15 , wherein at least two identical PDAF pixels are immediately next to each other.

18. The system of claim 15 , wherein a distance between two subsequent cross-sections is determined by one of a depth of focus and a numerical aperture of the lens.

Assignees

• Omnivision Tech Inc

Inventors

• Chan Anson
• Liu Lequn
• Jutamulia Suganda

Classifications

• G03B13/36 Primary

  Autofocus systems · CPC title

• H04N23/672

  based on the phase difference signals · CPC title

• H04N25/704

  Pixels specially adapted for focusing, e.g. phase difference pixel sets · CPC title

• H04N23/959

  by adjusting depth of field during image capture, e.g. maximising or setting range based on scene characteristics · CPC title

• G03B3/10

  Power-operated focusing · CPC title