Methods and apparatus for capturing images of an environment
Customer wide angle lenses and methods and apparatus for using such lenses in individual cameras as well as pairs of cameras intended for stereoscopic image capture are described. The lenses are used in combination with sensors to capture different portions of an environment at different resolutions. In some embodiments ground is capture at a lower resolution than sky which is captured at a lower resolution than a horizontal area of interest. Various asymmetries in lenses and/or lens and sensor placement are described which are particularly well suited for stereoscopic camera pairs where the proximity of one camera to the adjacent camera may interfere with the field of view of the cameras.
1. An image capture system, comprising:
a first camera, the first camera including:
a first sensor; and
a first fish eye lens having a shape which directs light of sky and ground portions of an environment to fewer pixel element sensors per unit area of the sky and ground than a horizontal environmental portion of interest so that the sky and ground portions are captured at a lower resolution than the horizontal environmental portion of interest; and
wherein the first fish eye lens is symmetric in the horizontal direction but not the vertical direction, said first fish eye lens directing light corresponding to the sky portion onto more pixel elements of said first sensor than light corresponding to the ground portion, said first sensor capturing said ground portion at a lower resolution than said sky and horizontal environmental portion of interest.
2. The image capture system of claim 1 , wherein the first fish eye lens has a field of view of at least 160 degrees in the vertical direction.
3. The image capture system of claim 2 , wherein the first fish eye lens also has a field of view of at least 160 degrees in the horizontal direction.
4. An image capture system, comprising:
a first camera, the first camera including:
a first sensor; and
a first fish eye lens having a shape which directs light of sky and ground portions of an environment to fewer pixel element sensors per unit area of the sky and ground than a horizontal environmental portion of interest so that the sky and ground portions are captured at a lower resolution than the horizontal environmental portion of interest; and
wherein said first fish eye lens has a center which is offset from a center of the first sensor in the horizontal dimension by an amount sufficient to avoid capture of a portion of lens of an adjacent camera included in a stereoscopic camera pair in which said first camera is included.
5. An image capture system, comprising:
a first camera, the first camera including:
a first sensor; and
a first fish eye lens having a shape which directs light of sky and ground portions of an environment to fewer pixel element sensors per unit area of the sky and ground than a horizontal environmental portion of interest so that the sky and ground portions are captured at a lower resolution than the horizontal environmental portion of interest; and
wherein said first fish eye lens is asymmetric in the horizontal direction and wherein said first camera is in a stereoscopic camera pair.
6. The image capture system of claim 5 , wherein said first fish eye lens is also asymmetric in the vertical direction.
7. The image capture system of claim 5 , further including:
a second camera, the second camera including:
a second sensor; and
a second asymmetric fish eye lens having a shape which directs light of sky and ground portions of an environment to fewer pixel element sensors per unit area of the sky and ground than a horizontal environmental portion of interest so that the sky and ground portions are captured at a lower resolution than the horizontal environmental portion of interest.
8. The image capture system of claim 1 , wherein the first fish eye lens directs light passing through an upper portion of the first lens onto a first portion of said first sensor and directs light passing through a lower portion of the first lens onto a second portion of the first sensor, said second portion of the first sensor being smaller than said first portion.
9. The image capture system of claim 8 , further comprising:
a second camera, the second camera including:
a first sensor; and
a second fish eye lens having a shape which directs light of sky and ground portions of an environment to fewer pixel element sensors per unit area of the sky and ground than a horizontal environmental portion of interest so that the sky and ground portions are captured at a lower resolution than the horizontal environmental portion of interest; and
wherein the second fish eye lens is symmetric in the horizontal direction but not the vertical direction, said second fish eye lens directing light corresponding to the sky portion onto more pixel elements of said second sensor than light corresponding to the ground portion, said second sensor capturing said ground portion at a lower resolution than said sky and horizontal environmental portion of interest.
10. The image capture system of claim 9 , wherein said second fish eye lens is positioned adjacent the first fish eye lens, a portion of said second fish eye lens obscuring a portion of the field of view of the first fish eye lens.
11. The image capture system of claim 10 , wherein the first sensor is shifted with respect to the center of the first fish eye lens resulting in a portion of the light passing through the first fish eye lens missing said first sensor.
12. The image capture system of claim 11 , wherein said portion of the light passing through the first fish eye lens missing said first sensor including light corresponding to the portion of the second fish eye lens that obscures the portion of the field of view of the first fish eye lens.
13. The image capture system of claim 11 , wherein the second sensor is shifted with respect to the center of the second fish eye lens resulting a portion of the light passing through the second fish eye lens missing said first sensor, said shift of the second sensor with respect to the center of the second fish eye lens being a shift in a horizontal direction which is equal and opposite the amount the first sensor is shifted with respect to the center of the first fish eye lens.
14. The image capture system of claim 4 , further comprising:
a second camera positioned adjacent said first camera.
15. The image capture system of claim 14 , wherein said first and second cameras form said stereoscopic camera pair, the second camera including:
a second asymmetric fish eye lens; and
wherein said second asymmetric fish eye lens has a center which is offset from a center of a second sensor in the horizontal dimension by an amount sufficient to avoid capture of a portion of the first fish eye lens of the first camera included in the stereoscopic camera pair.