Image pick-up device, method, and system utilizing a lens having plural regions each with different focal characteristics

1. An image pickup apparatus comprising:

a lens optical system having a plurality of regions including six regions having such optical characteristics that focal characteristics are made different from one another;

an image pickup device having a plurality of pixels on which light beams having passed through the lens optical system are incident; and

an arrayed optical device arranged between the lens optical system and the image pickup device for making light beams having passed through the six regions incident respectively on different pixels on the image pickup device,

wherein the plurality of pixels include a plurality of pixels belonging to first to sixth pixel groups,

light beams having passed through the six regions are incident on the first to sixth pixel groups, respectively,

the image pickup apparatus further comprising a signal processing section,

the signal processing section calculates a distance to an object using brightness information of a plurality of pixels obtained from a plurality of pixel groups of the first to sixth pixel groups, and

the signal processing section calculates the distance to the object based on degrees of sharpness of any two of six images formed by light beams having been incident on the six regions.

2. The image pickup apparatus of claim 1 , wherein:

where the object distance is within a certain range, a value of a ratio between degrees of sharpness of the any two of the six images has a correlation with the object distance; and

the signal processing section calculates the distance to the object based on the correlation and the ratio between the degrees of sharpness of the any two images.

3. The image pickup apparatus of claim 1 , wherein center points of six pixels included respectively in the first to sixth pixel groups are located at apices of a regular hexagon.

4. The image pickup apparatus of claim 1 , wherein:

the arrayed optical device is a microlens array in which optical elements, which are microlenses, are arranged in a hexagonal close-packed pattern; and

the arrangement is such that six pixels included respectively in the first to sixth pixel groups correspond to one optical element.

5. The image pickup apparatus of claim 4 , wherein each microlens optical element has a rotationally symmetric shape within a range of a predetermined radius from an optical axis of the optical element.

6. The image pickup apparatus of claim 1 , wherein the six regions are a plurality of regions arranged in point symmetry with each other with an optical axis of the lens optical system interposed therebetween.

7. The image pickup apparatus of claim 1 , wherein the six regions have generally an equal area and different radii of curvature as viewed from a direction along an optical axis of the lens optical system.

8. The image pickup apparatus of claim 1 , wherein:

the lens optical system further includes at least one region other than the six regions; and

the arrayed optical device makes light beams having passed through seven regions, including the six regions and the one region, incident on different pixels on the image pickup device.

9. The image pickup apparatus of claim 8 , further comprising a signal processing section, wherein:

the plurality of pixels include a plurality of pixels belonging to a seventh pixel group;

a light beam having passed through the one region is incident on the seventh pixel group; and

the signal processing section calculates a distance to an object using brightness information of a plurality of images obtained from a plurality of pixel groups of the first to seventh pixel groups on which light beams having passed through the seven regions are incident.

10. The image pickup apparatus of claim 8 , wherein:

a plurality of pixels of the image pickup device are arranged in n rows (n is an integer greater than or equal to 2); and

positions of center points of the plurality of pixels in a row direction are shifted from one row to another by half a pixel arrangement pitch.

11. The image pickup apparatus of claim 10 , wherein the seven regions include one central region located at an optical axis of the lens optical system, and six surrounding regions located around the central region.

12. The image pickup apparatus of claim 1 , wherein:

the lens optical system further comprises a stop; and

the plurality of regions are arranged in the vicinity of the stop.

13. The image pickup apparatus of claim 1 , wherein the arrayed optical device is formed on the image pickup device.

14. The image pickup apparatus of claim 13 , further comprising a microlens provided between the arrayed optical device and the image pickup device, wherein the arrayed optical device is formed on the image pickup device with the microlens therebetween.

15. An image pickup apparatus comprising:

a lens optical system having a plurality of regions including six regions having such optical characteristics that focal characteristics are made different from one another;

an image pickup device having a plurality of pixels on which light beams having passed through the lens optical system are incident; and

an arrayed optical device arranged between the lens optical system and the image pickup device for making light beams having passed through the six regions incident respectively on different pixels on the image pickup device,

wherein the plurality of pixels include a plurality of pixels belonging to first to sixth pixel groups,

light beams having passed through the six regions are incident on the first to sixth pixel groups, respectively,

the image pickup apparatus further comprising a signal processing section,

the signal processing section calculates a distance to an object using brightness information of a plurality of pixels obtained from a plurality of pixel groups of the first to sixth pixel groups, and

the signal processing section calculates the distance to the object based on a ratio between contrasts of any two of six images formed by light beams having been incident on the six regions.

16. The image pickup apparatus of claim 15 , wherein:

where the object distance is within a certain range, a value of the ratio between contrasts of the any two of the six images has a correlation with the object distance; and

the signal processing section calculates the distance to the object based on the correlation and the ratio between the contrasts of the any two images.

17. An image pickup apparatus comprising:

a lens optical system having a plurality of regions including six regions having such optical characteristics that focal characteristics are made different from one another;

an image pickup device having a plurality of pixels on which light beams having passed through the lens optical system are incident; and

an arrayed optical device arranged between the lens optical system and the image pickup device for making light beams having passed through the six regions incident respectively on different pixels on the image pickup device,

wherein the lens optical system further includes at least one region other than the six regions,

the arrayed optical device makes light beams having passed through seven regions, including the six regions and the one region, incident on different pixels on the image pickup device,

the image pickup apparatus further comprising a signal processing section,

the plurality of pixels include a plurality of pixels belonging to a seventh pixel group,

a light beam having passed through the one region is incident on the seventh pixel group,

the signal processing section calculates a distance to an object using brightness information of a plurality of images obtained from a plurality of pixel groups of the first to seventh pixel groups on which light beams having passed through the seven regions are incident, and

the signal processing section calculates the distance to the object based on a ratio between degrees of sharpness of any two of seven images formed by light beams having been incident on the seven regions.

18. The image pickup apparatus of claim 17 , wherein:

where the object distance is within a certain range, a value of the ratio between degrees of sharpness of the any two of the seven images has a correlation with the object distance; and

the signal processing section calculates the distance to the object based on the correlation and the ratio between the degrees of sharpness of the any two images.

19. An image pickup apparatus comprising:

a lens optical system having a plurality of regions including six regions having such optical characteristics that focal characteristics are made different from one another;

an image pickup device having a plurality of pixels on which light beams having passed through the lens optical system are incident; and

an arrayed optical device arranged between the lens optical system and the image pickup device for making light beams having passed through the six regions incident respectively on different pixels on the image pickup device,

wherein the lens optical system further includes at least one region other than the six regions,

the arrayed optical device makes light beams having passed through seven regions, including the six regions and the one region, incident on different pixels on the image pickup device,

the image pickup apparatus further comprising a signal processing section,

the plurality of pixels include a plurality of pixels belonging to a seventh pixel group,

a light beam having passed through the one region is incident on the seventh pixel group,

the signal processing section calculates a distance to an object using brightness information of a plurality of images obtained from a plurality of pixel groups of the first to seventh pixel groups on which light beams having passed through the seven regions are incident, and

the signal processing section calculates the distance to the object based on a ratio between contrasts of any two of seven images formed by light beams having been incident on the seven regions.

20. The image pickup apparatus of claim 19 , wherein:

where the object distance is within a certain range, a value of the ratio between contrasts of the any two of the seven images has a correlation with the object distance; and

the signal processing section calculates the distance to the object based on the correlation and the ratio between the contrasts of the any two images.

21. An image pickup apparatus comprising:

a lens optical system having a plurality of regions including four regions having such optical characteristics that focal characteristics are made different from one another;

an image pickup device including a plurality of pixels on which light beams having passed through the lens optical system are incident and which are arranged in n rows (n is an integer greater than or equal to 2); and

an arrayed optical device arranged between the lens optical system and the image pickup device for making light beams having passed through the four regions incident on different pixels on the image pickup device,

wherein positions of center points of the plurality of pixels in a row direction are shifted from one row to another by half a pixel arrangement pitch,

the four regions includes one central region located at an optical axis of the lens optical system, and three regions located around the central region; and

each of the three regions includes two regions arranged in point symmetry with an optical axis of the lens optical system interposed therebetween.