CODING APPARATUS, CODING METHOD AND PROGRAM
An encoding device includes: an acquisition unit that acquires point cloud data indicating a three-dimensional position of a subject in a spherical coordinate system; an angle data encoding unit that frequency-converts scanning angle data that is time-series data of a scanning angle of each of points included in the point cloud data, quantizes a coefficient, and encodes the quantized coefficient; and a distance data encoding unit that predicts, for each of the points, a distance from a position of a measurement source to a point to be encoded on the basis of a distance from the position of the measurement source to a neighboring point in a distance map having the scanning angle as an axis, and encodes distance data indicating the predicted distance.
1 . An encoding device comprising:
an acquirer configured to acquire point cloud data indicating a three-dimensional position of a subject in a spherical coordinate system;
an angle data encoder configured to frequency-convert scanning angle data that is time-series data of a scanning angle of each of points included in the point cloud data, to quantize a coefficient, and to encode the quantized coefficient; and
a distance data encoder configured to predict, for each of the points, a distance from a position of a measurement source to a point to be encoded on the basis of a distance from the position of the measurement source to a neighboring point in a distance map having the scanning angle as an axis, and to encode distance data indicating the predicted distance.
2 . The encoding device according to claim 1 , wherein the distance map is a two-dimensional map having two scanning angles in the spherical coordinate system as axes.
3 . The encoding device according to claim 1 ,
wherein the point cloud data includes time information indicating a time at which a position of each of the points is measured, and
the angle data encoder is configured to generate the scanning angle data by rearranging the scanning angles of the respective points on the basis of the time information.
4 . The encoding device according to claim 3 , wherein the distance data encoder is configured to encode the distance data in order from a point at which the time based on the time information is earliest.
5 . The encoding device according to claim 1 ,
wherein the acquirer is configured to group the point cloud data for each scan in a case where the point cloud data is data generated by a plurality of scans, and
the angle data encoder is configured to encode the scanning angle data for each group.
6 . The encoding device according to claim 1 , wherein the distance data encoder is configured to predict the distance from the position of the measurement source to the point to be encoded on the basis of an average value or a median value of distances from the position of the measurement source to a plurality of neighboring points in the distance map.
7 . An encoding method comprising:
acquiring point cloud data indicating a three-dimensional position of a subject in a spherical coordinate system;
frequency-converting scanning angle data that is time-series data of a scanning angle of each of points included in the point cloud data, quantizing a coefficient, and encoding the quantized coefficient; and
predicting, for each of the points, a distance from a position of a measurement source to a point to be encoded on the basis of a distance from the position of the measurement source to a neighboring point in a distance map having the scanning angle as an axis, and encoding distance data indicating the predicted distance.
8 . A program for causing a computer to function as the encoding device according to claim 1 .