Object-detecting device and method of extracting operation object

Abstract

An object-detecting device detects an operation object for operating an operating apparatus. The object-detecting device includes an imaging portion for imaging the operation object and an image processor for extracting the operation object. The operation object has a first face, on which outside light falls from outside into the operating apparatus, and a second face opposite to the first face. The imaging portion images the second face of the operation object. The object-detecting device can stably detect the operation object, even when an illuminance variation of outside light is large.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic diagram showing an object-detecting device according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram showing a construction of the device;

FIG. 3 is a graph showing a relationship between an illuminance of outside light and a brightness of a finger of a driver;

FIG. 4A is a differential image in which the illuminance of outside light is large, and FIG. 4B is a differential image in which the illuminance of outside light is small;

FIG. 5A is a differential image having noise, FIG. 5B is a graph showing the noise in an output signal, and FIG. 5C is a graph in which the signal is smoothed by a filter in the device;

FIG. 6 is a schematic diagram showing a construction of an object-detecting device according to a second embodiment; and

FIG. 7 is a flow chart showing a control of an object-detecting device according to a third embodiment.

Claims

1. An object-detecting device for detecting an operation object, which is used for operating an operating apparatus, the device comprising: an imaging portion for imaging the operation object; andan image processor for extracting the operation object, whereinthe operation object has a first face, on which outside light falls from outside into the operating apparatus, and a second face opposite to the first face, andthe imaging portion images the second face of the operation object.

2. The object-detecting device according to claim 1, wherein the image processor includes:a lighting portion for lighting the second face of the operation object;a memory for storing first and second images imaged by the imaging portion; anda controller for controlling an illuminance of the lighting portion and the imaging portion, whereinthe imaging portion images the first and second images in different conditions, in which the controller changes the illuminance of the lighting portion, andthe image processor compares the first and second images so as to extract the operation object.

3. The object-detecting device according to claim 2, wherein the controller turns on and off the lighting portion,the imaging portion images the first image, when the lighting portion is turned on, andthe imaging portion images the second image, when the lighting portion is turned off.

4. The object-detecting device according to claim 3, wherein the image processor extracts the operation object based on a differential image between the first image and the second image.

5. The object-detecting device according to claim 2, further comprising: a detector for detecting an illuminance of outside light, whereinthe controller controls the illuminance of the lighting portion based on the illuminance of outside light.

6. The object-detecting device according to claim 1, further comprising: a filter for smoothing an image of the operation object imaged by the imaging portion.

7. The object-detecting device according to claim 1, further comprising: a panel, on which the operation object is disposed so as to operate the apparatus, whereinthe imaging portion has a focus, which is spaced from a panel surface of the panel.

8. The object-detecting device according to claim 2, wherein the lighting portion emits infrared light, andthe imaging portion images an infrared image.

9. The object-detecting device according to claim 2, wherein the lighting portion has a first period, for which the lighting portion is turned on, and a second period, for which the lighting portion is turned off, andthe first period is approximately equal to the second period.

10. The object-detecting device according to claim 2, further comprising: a determining portion for determining the operation object to be at an operation position, whereinthe controller turns on the lighting portion only when the determining portion determines that the operation object is at the operation portion, andthe imaging portion images the operation object only when the determining portion determines that the operation object is at the operation portion.

11. The object-detecting device according to claim 2, further comprising: a detector for detecting a movement of the operation object, whereinthe lighting portion has a first period, for which the lighting portion is turned on, and a second period, for which the lighting portion is turned off, andthe controller controls the first period and the second period based on a speed of the movement of the operation object.

12. The object-detecting device according to claim 1, wherein the imaging portion is made of a plurality of optical parts and a plurality of imaging elements.

13. The object-detecting device according to claim 9, wherein the controller has a constant interval between the imaging of the first image and the imaging of the second image.

14. The object-detecting device according to claim 11, wherein the controller controls a timing for imaging the first and second images based on the speed of the movement of the operation object.

15. The object-detecting device according to claim 1, wherein the operating apparatus is mounted in a mobile unit.

16. A method of extracting an operation object for operating an apparatus, wherein the operation object has a first face, on which outside light falls, and a second face opposite to the first face, the method comprising: imaging a first image of the operation object, when a controller turns on a lighting portion to light the second face of the operation object;imaging a second image of the operation object, when the controller turns off the lighting portion; andcomparing the first image and the second image so as to extract the operation object.

17. The method according to claim 16, further comprising: memorizing the first image and the second image in a memory before the comparing, whereinthe comparing is performed by a differential image between the memorized first image and the memorized second image.

18. The method according to claim 16, wherein the apparatus is mounted in a mobile unit.