Information communication method

• US 9,756,255 B2
• Filed: 12/29/2016
• Issued: 09/05/2017
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Inventors: Oshima, Mitsuaki, Nakanishi, Koji, Aoyama, Hideki, Fuchigami, Ikuo, Shin, Hidehiko, Mukai, Tsutomu, Matsushita, Yosuke, Iida, Shigehiro, Yamada, Kazunori
• Primary Examiner(s): DOBSON, DANIEL G
• Application Number:
  US15/393,392
• Publication Number:
  US 20170111564A1
• Time in Patent Office: 250 Days
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04B 10/516 Details of coding or modulation
• CPC Class Codes: H04N 23/73 by influencing the exposure time

Abstract

A method is provided for obtaining information from a transmission device using an image sensor that includes a plurality of exposure lines. The method includes obtaining image data by starting exposure sequentially for the plurality of exposure lines each at a different time, starting exposure of a next exposure line before exposure of one exposure line ends, and imaging for a predetermined exposure time. The method also includes obtaining the information by demodulating data specified by a pattern of bright lines that appear in the image data, the bright lines corresponding to the plurality of exposure lines. The method further includes setting the predetermined exposure time so that a relation of t_E>t_HT is satisfied, where the predetermined exposure time is t_E μs, and a period of high frequency noise of a light source included in the transmission device is t_HT μs.

Claims

1. A method for obtaining information from a transmission device using an image sensor that includes a plurality of exposure lines, the method comprising:

obtaining image data by starting exposure sequentially for the plurality of exposure lines each at a different time, starting exposure of a next exposure line before exposure of one exposure line ends, and imaging for a predetermined exposure time;

obtaining the information by demodulating data specified by a pattern of bright lines that appear in the image data, the bright lines corresponding to the plurality of exposure lines; and

setting the predetermined exposure time so that a relation of t_E>

t_HT is satisfied, where the predetermined exposure time is t_E μ

s, and a period of high frequency noise of a light source included in the transmission device is t_HT μ

s.

2. The method according to claim 1,

wherein the period of the high frequency noise is less than or equal to 20 μ

s.

3. The method according to claim 2,

wherein the high frequency noise is caused by a switching power supply circuit included in the light source.

4. The method according to claim 3,

wherein the predetermined exposure time of t_E μ

s is an integral multiple of the period of the high frequency noise of t_HT μ

s.

5. The method according to claim 1,

wherein the predetermined exposure time is set so that in addition to the relation, a further relation of t_S/t_E≦

1.5 is satisfied, where a period of luminance change of the light source included in the transmission device is t_S μ

s.

6. The method according to claim 1,

wherein when a period of luminance change of the light source included in the transmission device is t_S μ

s, and when the period of t_S μ

s is greater than or equal to 15 μ

s and less than or equal to 35 μ

s, the predetermined exposure time of t_E μ

s is greater than or equal to 15 μ

s.

7. The method according to claim 6,

wherein when the period of t_S μ

s is greater than or equal to 35 μ

s and less than or equal to 54 μ

s, the predetermined exposure time of t_E μ

s is greater than or equal to 35 μ

s.

8. The method according to claim 7,

wherein when the period of t_S μ

s is greater than or equal to 54 μ

s and less than or equal to 74 μ

s, the predetermined exposure time of t_E μ

s is greater than or equal to 54 μ

s.

9. The method according to claim 8,

wherein when the period of t_S μ

s is greater than or equal to 74 μ

s, the predetermined exposure time of t_E μ

s is greater than or equal to 74 μ

s.

10. A non-transitory recording medium storing thereon a computer program, which when executed by a processor, causes the processor to perform operations, comprising:

obtaining image data by starting exposure sequentially for a plurality of exposure lines of an image sensor each at a different time, starting exposure of a next exposure line before exposure of one exposure line ends, and imaging for a predetermined exposure time;

obtaining information by demodulating data specified by a pattern of bright lines that appear in the image data, the bright lines corresponding to the plurality of exposure lines; and

setting the predetermined exposure time so that a relation of t_E>

t_HT is satisfied, where the predetermined exposure time is t_E μ

s, and a period of high frequency noise of a light source included in a transmission device is t_HT μ

s.

11. A device that obtains information from a transmission device using an image sensor that includes a plurality of exposure lines, the device comprising:

a processor; and

a memory storing thereon a computer program, which when executed by the processor, causes the processor to perform operations including;

obtaining image data by starting exposure sequentially for the plurality of exposure lines each at a different time, starting exposure of a next exposure line before exposure of one exposure line ends, and imaging for a predetermined exposure time;

obtaining the information by demodulating data specified by a pattern of bright lines that appear in the image data, the bright lines corresponding to the plurality of exposure lines; and

setting the predetermined exposure time so that a relation of t_E>

t_HT is satisfied, where the predetermined exposure time is t_E μ

s, and a period of high frequency noise of a light source included in the transmission device is t_HT μ

s.