Method for extracting features from a flow of digital video frames, and corresponding system and computer program product
In an embodiment, digital video frames in a flow are subjected to a method of extraction of features including the operations of: extracting from the video frames respective sequences of pairs of keypoints/descriptors limiting to a threshold value the number of pairs extracted for each frame; sending the sequences extracted from an extractor module to a server for processing with a bitrate value variable in time; receiving the aforesaid bitrate value variable in time at the extractor as target bitrate for extraction; and limiting the number of pairs extracted by the extractor to a threshold value variable in time as a function of the target bitrate.
1. An apparatus, comprising:
a generator circuit configured to generate, for each data block in a sequence of data blocks, a respective at least one value that represents a respective feature of the data block;
a receiver circuit configured to receive a target rate;
a rate circuit configured to adjust, in response to the target rate, a generation rate at which the generator generates the values;
wherein the target rate includes a target bit rate per unit of time; and
wherein the rate circuit is configured:
to convert the target bit rate per unit of time into a target bit rate per data block,
to determine one of a number of bits in the at least one value generated for a data block and an average number of bits in the at least one value generated for a data block, and
to adjust the generation rate in response to one of a difference between the target bit rate per data block and the number of bits and a difference between the target bit rate per data block and the average number of bits.
2. The apparatus of claim 1 wherein each data block in the sequence of data blocks includes a respective image in a sequence of images.
3. The apparatus of claim 1 wherein each data block in the sequence of data blocks includes a respective frame in a sequence of frames.
4. The apparatus of claim 1 wherein each of the at least one value includes a point of interest of the respective data block and a descriptor of the point of interest.
5. The apparatus of claim 4 wherein the descriptor includes a location of the point of interest within the respective data block.
6. The apparatus of claim 1 , further comprising:
a transmitter circuit configured to transmit the values to a destination; and
wherein the receiver is configured to receive the target rate from the destination.
7. The apparatus of claim 6 wherein the target bit rate includes a rate that is related to a rate at which the destination process the values.
8. The apparatus of claim 1 wherein the rate circuit is configured to adjust the generation rate in response to a difference between the target rate and the generation rate.
9. A method, comprising:
generating at a generation rate, for each data block in a sequence of data blocks, a respective set of at least one value that represents a respective feature of the data block;
receiving a target rate;
adjusting the generation rate in response to the target rate;
wherein the target rate includes a target bit rate per unit of time;
converting the target bit rate per unit of time into a target bit rate per data block;
determining either a number of bits in the at least one value generated for a data block and an average number of bits in the at least one value generated for a data block; and
adjusting the generation rate in response to either a difference between the target bit rate per data block and the number of bits and a difference between the target bit rate per data block and the average number of bits.
10. The method of claim 9 wherein each data block in the sequence of data blocks includes a respective image in a sequence of images.
11. The method of claim 9 , further comprising receiving the sequence of data blocks.
12. The method of claim 9 wherein each of the at least one value includes a point of interest of the respective data block and a descriptor of the point of interest.
13. The method of claim 9 , further comprising:
transmitting the sets to a computing circuit; and
wherein receiving the target rate includes receiving the target rate from the computing circuit.
14. The method of claim 9 , further comprising adjusting the generation rate in response to a difference between the target rate and the generation rate.