IMAGING DEVICE, IMAGING METHOD, AND PHOTOGRAPHING PROGRAM

• US 20090262215A1
• Filed: 07/31/2007
• Published: 10/22/2009
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Sano, Toshiyuki, Hoshino, Kouichi
• Granted Patent: US 8,264,595 B2
• Time in Patent Office: Days
• US Class Current: 348/229.100
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 25/533 by using differing integration times for different sensor regions
• CPC Class Codes: H04N 25/583 with different integration times
• CPC Class Codes: H04N 25/585 with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes
• CPC Class Codes: H04N 25/589 with different integration times, e.g. short and long exposures

Abstract

An imaging device comprises: an imaging element (1) capable of reading accumulated charges of different exposure times in a predetermined frame period, the imaging element being divided into groups for long-time exposure and short-time exposure; and a timing pulse generator (2) for adjusting read timings of the imaging element (1). A first read timing at which an accumulated charge of long-time exposure is read from the group for long-time exposure and a second read timing at which an accumulated charge of short-time exposure is read from the group for short-time exposure are adjusted separately from each other. This provides an imaging device that can extend the dynamic range according to the degree of contrast between light and shade of a subject.

Claims

1. An imaging device comprising:

an imaging unit capable of reading accumulated charge signals of different exposure times in a predetermined frame period from pixels in each of pixel groups, which are a long-time exposure pixel group and a short-time exposure pixel group, into which all pixels are divided;

a first reader for reading an accumulated charge signal of long-time exposure from said long-time exposure pixel group at a first read timing after a long-time exposure period in said frame period;

a second reader for reading an accumulated charge signal of short-time exposure from said short-time exposure pixel group at a second read timing after a short-time exposure period in said frame period;

a read timing adjuster for adjusting said first read timing and said second read timing separately from each other;

a long-time exposure signal generator for generating a long-time exposure signal, using said accumulated charge signal of long-time exposure read from said long-time exposure pixel group;

a short-time exposure signal generator for generating a short-time exposure signal, using said accumulated charge signal of short-time exposure read from said short-time exposure pixel group; and

a synthesizer for synthesizing said long-time exposure signal and said short-time exposure signal to generate an image signal representing all pixels.

2. The imaging device according to claim 1, comprising

a third reader for reading an accumulated charge signal of long-time exposure from said short-time exposure pixel group at said first read timing in said frame period, wherein said long-time exposure signal generator adds said accumulated charge signal of long-time exposure read from said short-time exposure pixel group to said accumulated charge signal of long-time exposure read from said long-time exposure pixel group to generate said long-time exposure signal.

3. The imaging device according to claim 2, comprising

a fourth reader for reading an accumulated charge signal of short-time exposure from said long-time exposure pixel group at said second read timing in said frame period,

wherein said long-time exposure signal generator adds said accumulated charge signal of short-time exposure read from said long-time exposure pixel group to said accumulated charge signal of long-time exposure read from said long-time exposure pixel group to generate said long-time exposure signal.

4. The imaging device according to claim 1, wherein pixels in said long-time exposure pixel group and pixels in said short-time exposure pixel group are alternately arranged in a longitudinal or transverse direction.

5. The imaging device according to claim 4, wherein said pixels are arranged so that a pixel array thereof is a Bayer array in each of said long-time exposure pixel group and said short-time exposure pixel group.

6. The imaging device according to claim 1,

wherein said first reader comprises:

a first transfer path that connects with each pixel in said long-time exposure pixel group; and

a first gate electrode which is to be a read path from each pixel in said long-time exposure pixel group to said first transfer path,

wherein said second reader comprises;

a second transfer path that connects with each pixel in said short-time exposure pixel group; and

a second gate electrode which is to be a read path from each pixel in said short-time exposure pixel group to said second transfer path, and

wherein said read timing adjuster applies a gate voltage to said first gate electrode at said first read timing and applies a gate voltage to said second gate electrode at said second read timing.

7. The imaging device according to claim 2,

wherein said third reader comprises:

a first transfer path that connects with each pixel in said short-time exposure pixel group; and

a third gate electrode which is to be a read path from each pixel in said short-time exposure pixel group to said first transfer path, and

wherein said read timing adjuster applies a gate voltage to said third gate electrode at said first read timing.

8. The imaging device according to claim 3,

wherein said fourth reader comprises:

a first transfer path that connects with each pixel in said long-time exposure pixel group; and

a first gate electrode to be a read path from each pixel in said long-time exposure pixel group to said first transfer path, and

wherein said read timing adjuster applies a gate voltage to said first gate electrode at said second read timing.

9. An imaging method wherein an imaging unit capable of reading accumulated charge signals of different exposure times in a predetermined frame period from pixels in each of pixel groups, which are a long-time exposure pixel group and a short-time exposure pixel group, into which all pixels are divided is used,

said method comprising:

adjusting a first read timing after a long-time exposure period in said frame period and a second read timing after a short-time exposure period in said frame period separately from each other;

reading an accumulated charge signal of long-time exposure from said long-time exposure pixel group at said first read timing;

reading an accumulated charge signal of short-time exposure from said short-time exposure pixel group at said second read timing;

generating a long-time exposure signal, using said accumulated charge signal of long-time exposure read from said long-time exposure pixel group;

generating a short-time exposure signal, using said accumulated charge signal of short-time exposure read from said short-time exposure pixel group; and

synthesizing said long-time exposure signal and said short-time exposure signal to generate an image signal representing all pixels.

10. An imaging program for imaging wherein an imaging unit capable of reading accumulated charge signals of different exposure times in a predetermined frame period from pixels in each of pixel groups, which are a long-time exposure pixel group and a short-time exposure pixel group, into which all pixels are divided is used, and

wherein said imaging unit is capable of adjusting a first read timing after a long-time exposure period in said frame period and a second read timing after a short-time exposure period in said frame period separately from each other, and

said program causes a computer to execute procedures of:

reading an accumulated charge signal of long-time exposure from said long-time exposure pixel group at said first read timing;

reading an accumulated charge signal of short-time exposure from said short-time exposure pixel group at said second read timing;

generating a long-time exposure signal, using said accumulated charge signal of long-time exposure read from said long-time exposure pixel group;

generating a short-time exposure signal, using said accumulated charge signal of short-time exposure read from said short-time exposure pixel group; and

synthesizing said long-time exposure signal and said short-time exposure signal to generate an image signal representing all pixels.