Method for measuring distance to object

• US 7,724,353 B2
• Filed: 08/03/2007
• Issued: 05/25/2010
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Iizuka, Nobuo
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Ratcliffe; Luke D
• Application Number:
  US11/890,179
• Publication Number:
  US 20080030711A1
• Time in Patent Office: 1,026 Days
• Field of Search: 356 301- 285
• US Class Current: 356/4.03
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves

Abstract

A method for calculating a distance to an object is provided. In this method, whether luminances received by at least one light receiving elements of a plurality of light receiving elements are equal to or higher than a predetermined value is determined. When luminances received by at least one light receiving elements are equal to or higher than a predetermined value, whether the luminances change in a time-series manner or not is determined. When the luminances change in a time-series manner, information is acquired from the time-series change. Then, a size of a light receiving region is detected based on a ratio of a light receiving element having received luminance with a predetermined value or more to the plurality of light receiving element. Based on the size of the light receiving region and the acquired information, the distance to the object is calculated.

Claims

1. A method comprising:

determining whether a luminance received by at least one light receiving element of a plurality of light receiving elements of an apparatus is equal to or higher than a predetermined value;

determining whether luminances received by the at least one light receiving element that has received the luminance are equal to or higher than the predetermined value change in a time-series manner;

acquiring information relating to a size of a light source from the time-series change when it is determined that the luminances change in the time-series manner;

detecting a size of a light receiving region based on a ratio of the at least one light receiving element that has received the luminances that change in the time-series manner to the plurality of light receiving elements; and

calculating a distance from the apparatus to the light source based on the size of the light receiving region and the acquired information relating to the size of the light source;

wherein the information relating to the size of the light source is contained in the luminances that change in the time-series manner provided by the light source.

2. The method according to claim 1, further comprising:

determining a shape of the light receiving region, wherein the distance from the apparatus to the light source is calculated based on the size of the light receiving region, the acquired information relating to the size of the light source, and the shape of the light receiving region.

3. The method according to claim 1, further comprising controlling imaging operation-related processings based on the calculated distance.

4. The method according to claim 3, wherein the imaging operation-related processings include reproduction or storage of information acquired from the time-series change, based on the calculated distance.

5. The method according to claim 3, wherein the imaging operation-related processings include a processing for displaying imaging-related auxiliary information based on the calculated distance.

6. The method according to claim 3, wherein the imaging operation-related processings include a processing for controlling a focusing section based on the calculated distance.

7. The method according to claim 3, wherein the imaging operation-related processings include a processing for processing an imaged image based on the calculated distance.

8. The method according to claim 3, wherein the imaging operation-related processings include a processing for controlling an optical system mechanism based on the calculated distance.

9. The method according to claim 1, further comprising controlling a display mode of displaying information acquired from the time-series change on a display section.

10. The method according to claim 9, wherein the controlling of the display mode comprises displaying the acquired information with images imaged by the plurality of light receiving elements.

11. The method according to claim 9, wherein the controlling of the display mode comprises displaying the acquired information in association with the image of the light source included in the images imaged by the plurality of light receiving elements.

16. The method according to claim 1, further comprising:

acquiring information relating to a shape of the light source from the time-series change; and

determining a shape of the light receiving region,

wherein the distance from the apparatus to the light source is calculated based on the size of the light receiving region, the acquired information relating to the size of the light source, the shape of the light receiving region, and the acquired information relating to the shape of the light source.

17. The method according to claim 1, further comprising controlling display of information acquired from the time-series change based on the calculated distance.

12. An apparatus, comprising:

a light receiving section including a plurality of light receiving elements;

a first determination section to determine whether a luminance received by at least one of the plurality of light receiving elements is equal to or higher than a predetermined value;

a second determination section to determine whether luminances received by the at least one light receiving element that has received the luminance are equal to or higher than the predetermined value change in a time-series manner;

an acquisition section to acquire information relating to a size of a light source from the time-series change when it is determined that the luminances change in the time-series manner;

a detection section to detect a size of a light receiving region based on a ratio of the at least one light receiving element having received the luminances that change in the time-series manner to the plurality of light receiving elements; and

a calculation section to calculate a distance from the apparatus to the light source based on the size of the light receiving region and the acquired information relating to the size of the light source;

wherein the information relating to the size of the light source is contained in the luminances that change in the time-series manner provided by the light source.

13. A computer-readable storage medium having a program stored thereon that is executable by a computer of an apparatus to perform functions comprising:

determining whether a luminance received by at least one light receiving element of a plurality of light receiving elements of the apparatus are equal to or higher than a predetermined value;

determining whether luminances received by the at least one light receiving element that has received the luminance are equal to or higher than the predetermined value change in a time-series manner;

acquiring information relating to a size of a light source from the time-series change when it is determined that the luminances change in the time-series manner;

detecting a size of a light receiving region based on a ratio of the at least one light receiving element that has received luminances that change in the time-series manner to the plurality of light receiving elements; and

calculating a distance from the apparatus to the light source based on the size of the light receiving region and the acquired information relating to the size of the light source;

wherein the information relating to the size of the light source is contained in the luminances that change in the time-series manner provided by the light source.

14. A distance measuring system comprising:

(i) a light source including;

a modulation section to modulate information relating to a size of the light source to a time-series luminance change; and

a luminance section which emits light having the time-series luminance change; and

(ii) a light receiving apparatus including;

a light receiving section which includes a plurality of light receiving elements and which receives the light from the light source;

a demodulation section to demodulate the time-series luminance change of the light received by the light receiving section to acquire the information relating to the size of the light source;

a detection section to detect a size of a light receiving region based on a ratio of an area of the light receiving elements that received the light to the plurality of light receiving elements; and

a measurement section to measure, based on the size of the region detected by the detection section and the information relating to the size of the light source acquired by the demodulation section, a distance between the light source and a position of the light receiving apparatus.

15. A light source apparatus, comprising:

a light source;

a modulation section to modulate information relating to a size of the light source to a time-series luminance change; and

a luminance section that controls the light section to emit light having the time-series luminance change,

wherein the emitted light having the time-series luminance change is receivable by a light receiving apparatus to enable the light receiving apparatus to calculate a distance to the light source.