Range image producing method and apparatus for image taking

• US 20080043218A1
• Filed: 08/16/2007
• Published: 02/21/2008
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Murayama, Jin
• Granted Patent: US 7,477,361 B2
• Time in Patent Office: Days
• US Class Current: 356/5.04
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G02B 7/32 using active means, e.g. light emitter including both an active and a passive focus detecting device G02B7/285; using ultrasound G02B7/40
• CPC Class Codes: G02B 7/36 using image sharpness techniques , e.g. image processing techniques for generating autofocus signals image data processing per se G06T; in cameras having a solid state image sensor H04N23/67
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 5/2226 Determination of depth image, e.g. for foreground/background separation determining depth by image analysis in general G06T7/50; segmentation by image analysis in general G06T7/10

Abstract

An apparatus for image taking includes a range image sensor, in which a range image is produced in which a distance is represented with a pixel value by image taking of a principal object from an image taking position. An image pickup device receives light reflected by the principal object, to output an image signal for respective pixels. A light reception control unit changes over a reception sequence and reception time, and causes the image pickup device to output image signals associated with first and second distance ranges. The second distance range is a distance range where the principal object exists and is over the first distance range. A first range image and second range image, are formed according to the image signals. Blank portions are designated within the second range image by comparison of the first range image and second range image, to compensate for the blank portions.

Claims

1. A range image producing method of producing a range image in which a distance is represented with a pixel value by image taking of a scene containing a principal object from an image taking position with an image pickup device, comprising steps of:

applying light modulated at a predetermined period to said scene;

determining a first distance range and a second distance range, wherein said first distance range is from an image taking position to a point short of said principal object, and said second distance range is a distance range defined by eliminating said first distance range from a range between said image taking position and said principal object;

receiving said light reflected by an object located in a first distance range with said image pickup device in a reception sequence and reception time according to said first distance range, to output a first image signal;

receiving said light reflected by said principal object with said image pickup device in a reception sequence and reception time according to said second distance range, to output a second image signal;

forming a first range image and a second range image according to respectively said first and second image signals; and

designating blank portions within said second range image by comparison of said first and second range images, to compensate for said blank portions for forming said range image.

2. A range image producing method as defined in claim 1, wherein said blank portions are portions derived from low reflectance in said principal object.

3. A range image producing method as defined in claim 1, wherein said range image forming step includes:

a) extracting a first closed region disposed in said first range image and having a closed contour;

b) generating closed region data of information of a position and form of said first closed region;

c) extracting a second closed region disposed in said second range image and having a closed contour;

d) determining blank portions from said second closed region;

e) comparing said blank portions with said closed region data, to designate a blank portion unrelated with said closed region data;

f) compensating for said blank portion unrelated with said closed region data.

4. A range image producing method as defined in claim 3, wherein said first closed region is derived from a small object in a micro size located in said first distance range.

5. A range image producing method as defined in claim 1, wherein in said light applying step, infrared rays are emitted, and said first and second range images are photographed by response to said infrared rays.

6. A range image producing method as defined in claim 5, further comprising steps of:

image taking of said scene with a visible light image pickup device, to form a visible light image; and

extracting an image of said principal object from said visible light image according to said second range image.

7. An apparatus for image taking and for producing a range image in which a distance is represented with a pixel value by image taking of a scene containing a principal object from an image taking position with an image pickup device, comprising:

a light source for applying light modulated at a predetermined period to said scene;

a light reception control unit for changing over a reception sequence and reception time between a first receiving condition for a first distance range and a second receiving condition for a second distance range in a scanning period of one frame, to cause said image pickup device to output first and second image signals associated with said first and second receiving conditions, wherein said first distance range is from an image taking position to a point short of said principal object, and said second distance range is a distance range defined by eliminating said first distance range from a range between said image taking position and said principal object;

an image forming unit for forming a first range image and a second range image according to respectively said first and second image signals; and

an image processor for designating blank portions within said second range image by comparison of said first and second range images, to compensate for said blank portions for forming said range image.

8. An apparatus for image taking as defined in claim 7, wherein said image processor includes:

a closed region extractor for extracting a first closed region disposed in said first range image and having a closed contour, and a second closed region disposed in said second range image and having a closed contour;

a data generator for generating closed region data of information of a position and form of said first closed region;

a blank determiner for determining blank portions from said second closed region;

a comparison unit for comparing said blank portions with said closed region data, to designate a blank portion unrelated with said closed region data;

a compensator for compensating for said blank portion unrelated with said closed region data among said blank portions.

9. An apparatus for image taking as defined in claim 8, wherein said light source includes an infrared light emitting diode, and said image pickup device is an infrared image pickup device for image taking in response to infrared rays.

10. An apparatus for image taking, comprising:

an image taking lens for focusing light from a scene containing a principal object;

a visible light image pickup device for receiving said light from said scene, to output a visible image signal by photoelectric conversion;

a light source for applying infrared rays modulated at a predetermined period to said scene;

path splitting optics disposed between said image taking lens and said visible light image pickup device;

an infrared image pickup device, disposed in a light path of split of said path splitting optics, for carrying out photoelectric conversion of said infrared rays reflected by said object in said scene, to output an infrared image signal;

a light reception control unit for changing over a reception sequence and reception time between a first receiving condition for a first distance range and a second receiving condition for a second distance range in a scanning period of one frame, to cause said infrared image pickup device to output first and second infrared image signals associated with said first and second receiving conditions, wherein said first distance range is from an image taking position to a point short of said principal object, and said second distance range is a distance range defined by eliminating said first distance range from a range between said image taking position and said principal object;

an image forming unit for forming a visible light image according to said visible image signal, and for forming a first range image and a second range image according to respectively said first and second infrared image signals;

an image processor for designating blank portions within said second range image by comparison of said first and second range images, to compensate for said blank portions for forming said range image; and

a visible light image extractor for extracting an image from said visible light image according to said second range image.

11. An apparatus for image taking as defined in claim 10, wherein said image processor includes:

a closed region extractor for extracting a first closed region disposed in said first range image and having a closed contour, and a second closed region disposed in said second range image and having a closed contour;

a data generator for generating closed region data of information of a position and form of said first closed region;

a blank determiner for determining blank portions from said second closed region;

a comparison unit for comparing said blank portions with said closed region data, to designate a blank portion unrelated with said closed region data;

a compensator for compensating for said blank portion unrelated with said closed region data among said blank portions.