Image reception terminal, image communication system, image reception method, and recording medium

An image communication system comprising,:

• an image receiving terminal;
• and
• an image transmitting terminal,
• wherein the image receiving terminal includes:
• a first communicator configured to receive communication packets from the image transmitting terminal using a wireless communication channel:
• and
• one or more first processors,
• an image of one frame is divided into one or more images and each communication packet includes the divided image,
• the image of one frame corresponds to a plurality of communication packets,
• the first processor is configured to generate a display image of one frame from the divided images included in the plurality of communication packets received by the first communicator,
• the first processor is configured to generate a vertical synchronization signal on the basis of a clock,
• the first processor is configured to output the display image to a monitor in synchronization with the vertical synchronization signal,
• the first processor is configured to measure a plurality of elapsed times by measuring an elapsed time each time the vertical synchronization signal is generated, each elapsed time included in the plurality of elapsed times being a time period from a time point at which the vertical synchronization signal is generated to a time point at which a specific packet is received by the first communicator, and the specific packet being one of the plurality of communication packets corresponding to the image of one frame,
• the first processor is configured to set a determination reference time on the basis of the plurality of measured elapsed times,
• the first processor is configured to determine whether the communication channel which is used by the first communicator is to be switched to another communication channel on the basis of the set determination reference time and the elapsed time measured after the determination reference time has been set,
• the first processor is configured to control switching of the communication channel which is used by the first communicator on the basis of the result of determination of the communication channel, and
• the image transmitting terminal includes:
• an imaging device configured to perform imaging every imaging cycle and output the image of one frame every imaging cycle;
• a second processor configured to generate the communication packet including the divided image included in the image of one frame;
• and
• a second communicator configured to transmit the communication packets to the image receiving terminal using the communication channel.

An image receiving method comprising:

• a first step of causing an image receiving terminal to receive communication packets from an image transmitting terminal using a wireless communication channel by a communicator, image of one frame being divided into one or more images, each communication packet including the divided image, the image of one frame corresponding to a plurality of communication packets;
• a second step of causing the image receiving terminal to generate a display image of one frame from the divided images included in the plurality of communication packets received by the communicator,
• a third step of causing the image receiving terminal to output the display image to a monitor in synchronization with a vertical synchronization signal, the vertical synchronization signal being generated on the basis of a clock,
• a fourth step of causing the image receiving terminal to measure a plurality of elapsed times by measuring an elapsed time each time the vertical synchronization signal is generated, each elapsed time included in the plurality of elapsed times being a time period from a time point at which the vertical synchronization signal is generated to a time point at which a specific packet is received by the communicator;
• the specific packet being one of the plurality of communication packets corresponding to the image of one frame;
• a fifth step of causing the image receiving terminal to set a determination reference time on the basis of the plurality of measured elapsed times;
• a sixth step of causing the image receiving terminal to determine whether the communication channel which is used by the communicator is to be switched to another communication channel on the basis of the set determination reference time and the elapsed time measured alter the determination reference time has been set;
• and
• a seventh step of causing the image receiving terminal to control switching of the communication channel which is used by the communicator on the basis of the result of determination of the communication channel.

A non-transitory computer-readable recording medium having a program recorded thereon, the program causing a computer to perform:

• a first step of receiving communication packets from an image transmitting terminal using a wireless communication channel by a communicator;
• an image of one frame being divided into one or more images, each communication packet including the divided image, the image of one frame corresponding to a plurality of communication packets;
• a second step of generating a display image of one frame from the divided images included in the plurality of communication packets received by the communicator;
• a third step of outputting the display image to a monitor in synchronization with a vertical synchronization signal, the vertical synchronization signal being generated on the basis of a clock,
• a fourth step of measuring a plurality of elapsed times by measuring an elapsed time each time the vertical synchronization signal is generated, each elapsed time included in the plurality of elapsed times being a time period from a time point at which the vertical synchronization signal is generated to a time point at which a specific packet is received by the communicator, the specific packet being one of the plurality of communication packets corresponding to the image of one frame;
• a fifth step of setting a determination reference time on the basis of the plurality of measured elapsed times;
• a sixth step of determining whether the communication channel which is used by the communicator is to be switched to another communication channel on the basis of the set determination reference time and the elapsed time measured after the determination reference time has been set;
• and
• a seventh step of controlling switching of the communication channel which is used by the communicator on the basis of the result of determination of the communication channel.