Unidirectional transfer of data from sender to receiver
A method, system and devices are provided for unidirectional transfer of data from a sender device ( 100 ) to a receiver device ( 200 ). At the sender device, respective parts of the data are encoded to generate respective 2D barcodes, and the 2D barcodes are sequentially displayed on a display ( 142 ). At the receiver device, an image sensor ( 222 ) is used to capture the sequentially displayed 2D barcodes to obtain a series of captured images, and in each or a subset of the series of captured images, detect a position of a respective 2D barcode in the captured image, scan the 2D barcode at the identified position to obtain barcode data, and decode the barcode data to, together with the barcode data obtained from other captured images, obtain a received version of the transmitted data.
1. A computer-implemented method for unidirectional transfer of data from a sender device to a receiver device, wherein the sender device comprises or is connected to a display and the receiver device comprises or is connected to an image sensor, comprising:
(i) at the sender device:
accessing data to be transmitted to the receiver device;
encoding respective parts of the data to generate respective 2D barcodes; and
(iii) sequentially displaying the 2D barcodes on the display; and
(ii) at the receiver device:
using the image sensor, capturing the sequentially displayed 2D barcodes to obtain a series of captured images, and in each or a subset of the series of captured images:
detecting a position of a respective 2D barcode in the captured image;
scanning the 2D barcode at the identified position to obtain barcode data; and
decoding the barcode data to, together with the barcode data obtained from other captured images, obtain a received version of the transmitted data, wherein
the method further comprising, at the sender device, generating a respective 2D barcode using a mask pattern, and at the receiver device, decoding respective barcode data based on the mask pattern, wherein the mask pattern is a spatiotemporal mask pattern which is different for consecutive pairs of the sequentially displayed 2D barcodes.
2. The method according to claim 1 , wherein the spatiotemporal mask pattern is a video or is obtained from a video, wherein the video is accessible to the sender device and the receiver device.
3. The method according to claim 1 , wherein the spatiotemporal mask pattern is generated algorithmically as a pseudo-random pattern using a seed, wherein the seed is accessible to the sender device and the receiver device.
4. The method according to claim 1 , further comprising, at the sender device, displaying spatial markers in spatial relation to the barcode data of respective 2D barcodes to facilitate detection of the 2D barcodes in the series of captured images, wherein an appearance of at least one of the spatial markers varies between the sequentially displayed 2D barcodes.
5. The method according to claim 4 , wherein the at least one spatial marker varies in appearance between the sequentially displayed 2D barcodes at a temporal frequency which is different from the temporal frequency at which the barcode data in the respective 2D barcodes is refreshed, for example higher.
6. The method according to claim 4 , wherein the at least one spatial marker comprises a line segment delineating at least part of the 2D barcode, wherein the line segment preferably has a primary color or a secondary color.
7. The method according to claim 1 , further comprising, at the sender device, sequentially displaying the 2D barcodes to cause the barcode data in the 2D barcodes to be refreshed at a first temporal frequency, and at the receiver device, capturing images at a second temporal frequency, wherein the second temporal frequency is higher than the first temporal frequency, for example at least twice as high.
8. The method according to claim 7 , further comprising, at the receiver device, identifying which captured images contain unique 2D barcodes by determining differences between consecutive pairs of captured images.
9. The method according to claim 8 , further comprising, at the receiver device, if two or more consecutive captured images are identified to show a same 2D barcode, selecting one of the two or more captured images for extraction of the barcode data, for example a middle image in case of three or more captured images.
10. The method according to claim 1 , further comprising, at the sender device, displaying a video within a spatial subregion of the 2D barcodes.
11. A non-transitory computer-readable medium, wherein the computer-readable medium comprises data representing instructions arranged to cause a processor subsystem of a sender device to unidirectionally transfer data from the sender device to a receiver device by:
accessing the data to be transmitted to the receiver device;
encoding respective parts of the data to generate respective 2D barcodes; and
sequentially displaying the 2D barcodes on a display of the sender device; wherein
the instructions are further arranged to cause the processor subsystem to generate a respective 2D barcode using a mask pattern, wherein the mask pattern is a spatiotemporal mask pattern which is different for consecutive pairs of the sequentially displayed 2D barcodes.
12. A sender device configured for unidirectional transfer of data to a receiver device, comprising:
a data storage interface to a data storage;
a display output to a display ( 142 ); and
a processor subsystem configured to:
via the data storage interface, access the data to be transmitted to the receiver device;
encode respective parts of the data to generate respective 2D barcodes;
via the display output, sequentially display the 2D barcodes on the display, wherein
the processor subsystem is further configured to generate a respective 2D barcode using a mask pattern, wherein the mask pattern is a spatiotemporal mask pattern which is different for consecutive pairs of the sequentially displayed 2D barcodes.
13. A receiver device configured for receiving data from a sender device, wherein the sender device is configured to transmit the data by sequentially displaying 2D barcodes on a display, comprising:
a sensor interface to an image sensor;
a processor subsystem configured to:
using the image sensor, capture the sequentially displayed 2D barcodes to obtain a series of captured images, and in each or a subset of the series of captured images:
detect a position of a respective 2D barcode in the captured image;
scan the 2D barcode at the identified position to obtain barcode data; and
decode the barcode data to, together with the barcode data obtained from other captured images, obtain a received version of the transmitted data wherein
a respective 2D barcode is generated at the sender device using a mask pattern, wherein the mask pattern is a spatiotemporal mask pattern which is different for consecutive pairs of the sequentially displayed 2D barcodes, and wherein the processor subsystem is further configured to decode respective barcode data based on the mask pattern.
14. A non-transitory computer-readable medium, wherein the computer-readable medium comprises data representing instructions arranged to cause a processor subsystem of a receiver device to receive a unidirectional transfer of data from a sender device by:
using an image sensor of the receiver device, capturing a sequentially displayed 2D barcodes displayed on a display of the sender device to obtain a series of captured images, and in each or a subset of the series of captured images:
detecting a position of a respective 2D barcode in the captured image;
scanning the 2D barcode at the identified position to obtain barcode data;
decoding the barcode data to, together with the barcode data obtained from other captured images, obtain a received version of the transmitted data; wherein
a respective 2D barcode is generated at the sender device using a mask pattern, wherein the mask pattern is a spatiotemporal mask pattern which is different for consecutive pairs of the sequentially displayed 2D barcodes, and wherein the instructions are further arranged to cause the processor subsystem to decode respective barcode data based on the mask pattern.