Electronic device with multiple lenses and lens switching method

Patent metadata

Field	Value
Publication number	US-10516819-B2
Application number	US-201715697025-A
Country	US
Kind code	B2
Filing date	Sep 6, 2017
Priority date	Sep 7, 2016
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

An electronic device able to automatically select one of a plurality of lenses includes a lens module, an image sensor, a focusing module, and a processor. The lens module includes a standard lens, a macro lens, and a telephoto lens. The image sensor captures images and the focusing module controls the lenses to automatically focus on the object. The processor selects the standard lens as a current lens, obtains a first focusing distance at a first moment and a second focusing distance at a second moment, and determines to switch the current lens or not to switch according to a comparison of the first and second focusing distances. The second moment is later than the first moment. A lens switching method is also provided.

First claim

What is claimed is:

1. An electronic device, comprising:
a lens module comprising a plurality of lenses including a standard lens, a macro lens, and a telephoto lens;
an image sensor capturing images of an object through one of the lenses;
a focusing module comprising a voice coil motor for driving the standard lens, the macro lens, and the telephoto lens to automatically focus on the object; and
a processor electrically connected to and controlling the lens module, the image sensor, and the focusing module, the processor selecting the standard lens as a current lens, obtaining a first focusing distance at a first moment and a second focusing distance at a second moment, and determining whether switching the current lens to one of the macro lens and the telephoto lens according to a comparison of the second focusing distance and the first focusing distance;
wherein the second moment is later than the first moment; and
wherein when the second focusing distance is greater than the first focusing distance, the processor further determines whether a crop ratio of the image captured by the current lens is smaller than a second predetermined value; wherein when the crop ratio is greater than or equal to the second predetermined value, the processor does not switch the current lens; wherein when the crop ratio is smaller than the second predetermined value, the processor switches the current lens to the telephoto lens.

2. The electronic device as claimed in claim 1 , wherein when the second focusing distance is smaller than the first focusing distance, the processor further determines whether switching the current lens to the macro lens; wherein when the second focusing distance is greater than the first focusing distance, the processor further determines whether switching the current lens to the telephoto lens.

3. The electronic device as claimed in claim 1 , wherein when the second focusing distance is smaller than the first focusing distance, the processor further determines whether a quality of the image captured by the current lens meets a predetermined condition; wherein when the quality of the image captured by the current lens meets the predetermined condition, the processor does not switch the current lens; when the quality of the image captured by the current lens does not meet the predetermined condition, the processor further determines whether switching the current lens to the macro lens.

4. The electronic device as claimed in claim 3 , wherein when the quality of the image captured by the current lens does not meet the predetermined condition, the processor further determines whether a current focusing distance reaches a lower limit value of a focusing distance of the lens module; wherein when the current focusing distance reaches the lower limit value, the processor switches the current lens to the macro lens; when the current focusing distance does not reach the lower limit value, the processor does not switch the current lens.

5. The electronic device as claimed in claim 3 , wherein the predetermined condition is a value of a contrast or a value of a sharpness of an image captured by the current lens is greater than a first predetermined value.

6. The electronic device as claimed in claim 1 , wherein the image captured by the current lens is a sub-image cropped from an original image captured by the image sensor and then enlarged, the crop ratio is a ratio of a size of the cropped sub-image to a size of the original image.

7. A lens switching method applied in an electronic device, the lens switching method is stored in a storage of the electronic device and operated by a processor of the electronic device, the lens switching method comprising:
selecting a standard lens as a current lens;
obtaining a first focusing distance at a first moment and a second focusing distance at a second moment; and
determining whether switching the current lens to a macro lens or a telephoto lens according to a comparison of the second focusing distance and the first focusing distance;
wherein the second moment is later than the first moment; and
wherein when the second focusing distance is greater than the first focusing distance, further determining whether a crop ratio of an image captured by the current lens is smaller than a second predetermined value; wherein when the crop ratio is greater than or equal to the second predetermined value, the current lens is not switched; wherein when the crop ratio is smaller than the second predetermined value, switching the current lens to the telephoto lens.

8. The lens switching method as claimed in claim 7 , wherein when the second focusing distance is smaller than the first focusing distance, further determining whether switching the current lens to the macro lens; wherein when the second focusing distance is greater than the first focusing distance, further determining whether switching the current lens to the telephoto lens.

9. The lens switching method as claimed in claim 7 , wherein when the second focusing distance is smaller than the first focusing distance, further determining whether a quality of the image captured by the current lens meets a predetermined condition; wherein when the quality of the image captured by the current lens meets the predetermined condition, the current lens is not switched; wherein when the quality of the image captured by the current lens does not meet the predetermined condition, further determining whether switching the current lens to the macro lens.

10. The lens switching method as claimed in claim 9 , wherein when the quality of the image captured by the current lens does not meet the predetermined condition, further determining whether a current focusing distance reaches a lower limit value of a focusing distance of the lens module; wherein when the current focusing distance reaches the lower limit value, switching the current lens to the macro lens; wherein when the current focusing distance does not reach the lower limit value, the current lens is not switched.

11. The lens switching method as claimed in claim 9 , wherein the predetermined condition is a value of a contrast or a value of a sharpness of an image captured by the current lens is greater than a first predetermined value.

12. The lens switching method as claimed in claim 7 , wherein the image captured by the current lens is a sub-image cropped from an original image captured by the image sensor and then enlarged, the crop ratio is a ratio of a size of the cropped sub-image to a size of the original image.

Assignees

• Chiun Mai Communication Systems Inc

Inventors

• Chien How-Wen
• Chang Sung-Chieh

Classifications

• G03B13/36 Primary

  Autofocus systems · CPC title

• H04N23/67 Primary

  Focus control based on electronic image sensor signals · CPC title

• G02B7/282

  Autofocusing of zoom lenses · CPC title

• G02B7/021

  for more than one lens · CPC title

• G03B17/14

  interchangeably · CPC title