Receiving device

1. A receiving device comprising:

a receiving unit that receives, via a receiving antenna, a first image signal in a first receiving period and a second image signal in a second receiving period, each of the first image signal and second image signal including an in-vivo image of a subject that is captured by an in-vivo-image acquiring device introduced into the subject;

a transmitting unit that wirelessly transmits the first image signal and the second image signal to a real-time display device that displays the in-vivo image included in the first image signal and the in-vivo image included in the second image signal in real time;

a detecting unit that detects a length of a first non-receiving period in which the receiving unit does not receive any image signal, the first non-receiving period being immediately after the first receiving period and immediately before the second receiving period; and

a control unit that estimates, based on the length of the first non-receiving period detected by the detecting unit, a length of a second non-receiving period in which the receiving unit does not receive any image signal, the second non-receiving period being immediately after the second receiving period, and performs a control, based on the estimated length of the second non-receiving period, to cause the transmitting unit to wirelessly transmit the second image signal to the real-time display device during the second non-receiving period.

2. The receiving device according to claim 1 , further comprising a data reducing unit that reduces a data amount of the image signal to be wirelessly transmitted to the real-time display device, wherein

the control unit calculates a data amount that can be wirelessly transmitted by the transmitting unit during the non-receiving period, and performs a control to reduce the image signal to an amount equal to or smaller than the calculated data amount.

3. The receiving device according to claim 2 , wherein the control unit determines whether the in-vivo image included in the image signal having a reduced data amount equal to or smaller than the calculated data amount is effective, and performs a control to wirelessly transmit the image signal having the reduced data amount equal to or smaller than the calculated data amount when the in-vivo image is determined to be effective, while performing a control to wirelessly transmit the image signal in a data amount capable of including an effective in-vivo image by segmenting the signal to be wirelessly transmitted during a plurality of the non-receiving periods when the in-vivo image is determined to be ineffective.

4. The receiving device according to claim 3 , wherein when the in-vivo image included in the image signal having the reduced data amount equal to or smaller than the calculated data amount is determined to be ineffective, the control unit performs a control to reduce the image signal to a minimum data amount capable of including an effective in-vivo image and to wirelessly transmit the image signal reduced to the minimum data amount by segmenting the signal to be wirelessly transmitted during the plural non-receiving periods.

5. The receiving device according to claim 2 , wherein the data reducing unit is a compressing unit that compresses the image signal.

6. The receiving device according to claim 2 , wherein the data reducing unit is a pixel thinning unit that performs pixel thinning for the in-vivo image included in the image signal.

7. The receiving device according to claim 1 , wherein the control unit calculates a transmission rate sufficient to wirelessly transmit the image signal during the non-receiving period and performs a control to wirelessly transmit the image signal at the calculated transmission rate.

8. The receiving device according to claim 7 , wherein the control unit controls at least one of a modulation method and a transmission frequency of the transmitting unit and causes the transmitting unit to wirelessly transmit the image signal at the calculated transmission rate.