Method for measuring the topography of an environment

A method for forming a point cloud corresponding to the topography of an imaged environment comprising:

• acquiring a first image of the environment with a camera having a wide field of view lens mounted on a vehicle;
• changing the camera pose by an adjustment that is more than a threshold;
• acquiring a second image of the environment with the camera at the changed pose;
• mapping the first image onto a first surface to form a first mapped image;
• mapping the second image onto a second surface to form a second mapped image, the first surface and the second surface being defined by the same non-planar geometry,
• wherein the non-planar geometry defines a cylindrical surface and is symmetric about an optical axis of the camera,
• wherein the non-planar geometry comprises:
• a first non-planar surface;
• and
• a second non-planar surface, the first non-planar surface extending from the camera to the second non-planar surface, and the second non-planar surface converging from the first non-planar surface towards the optical axis,
• wherein the second non-planar surface defines a frusto-conical surface;
• dividing the one of the first or second mapped images into blocks of pixels;
• for each block of pixels, forming a depth map by performing a search through the other of the first or second mapped images to evaluate a disparity in the position of the location of the block of pixels in each of the mapped images;
• converting the depth map into a portion of a point cloud corresponding to the local topography of the environment surrounding the vehicle as it moves through the environment;
• and
• scaling the point cloud according to the adjustment in camera pose.

A method for forming a point cloud corresponding to the topography of an imaged environment comprising:

• acquiring a first image of the environment with a camera having a wide field of view lens mounted on a vehicle;
• changing the camera pose by an adjustment that is more than a threshold;
• acquiring a second image of the environment with the camera at the changed pose;
• mapping the first image onto a first surface to form a first mapped image;
• mapping the second image onto a second surface to form a second mapped image, the first surface and the second surface being defined by the same non-planar geometry,
• wherein the non-planar geometry defines a cylindrical surface,
• wherein the non-planar geometry is symmetric about an optical axis of the camera,
• wherein the non-planar geometry comprises:
• a first non-planar surface;
• and
• a second non-planar surface, the first non-planar surface extending from the camera to the second non-planar surface, and the second non-planar surface converging from the first non-planar surface towards the optical axis,
• wherein the second non-planar surface defines a hemispherical surface;
• dividing the one of the first or second mapped images into blocks of pixels;
• for each block of pixels, forming a depth map by performing a search through the other of the first or second mapped images to evaluate a disparity in the position of the location of the block of pixels in each of the mapped images;
• converting the depth map into a portion of a point cloud corresponding to the local topography of the environment surrounding the vehicle as it moves through the environment;
• and
• scaling the point cloud according to the adjustment in camera pose.