Image processing apparatus, identification apparatus, method for determining bit sequence and computer readable medium

1. An image processing apparatus comprising:

an image acquisition unit that acquires an image read from a medium having the image printed thereon, the image representing a specific bit sequence;

an information acquisition unit that acquires a state information piece indicating a reading reliability state of the image acquired by the image acquisition unit, the state information piece being assigned to each bit;

a detection unit that detects a bit sequence from the image acquired by the image acquisition unit; and

a determination unit that determines the specific bit sequence on the basis of the bit sequence detected by the detection unit and the state information piece acquired by the information acquisition unit.

2. The image processing apparatus according to claim 1 , wherein

the bit sequence detected by the detection unit includes a plurality of partial bit sequences respectively corresponding to a plurality of partial images forming the image acquired by the image acquisition unit, and

the state information piece acquired by the information acquisition unit includes a plurality of partial state information pieces respectively indicating reading reliability states of the plurality of partial images.

3. The image processing apparatus according to claim 2 , wherein

the plurality of partial images respectively represent bit sequences in a plurality of blocks after the specific bit sequence is encoded with Reed-Solomon (RS) coding, and

the determination unit determines the specific bit sequence by performing correction with an RS code on the assumption that, when a specific partial state information piece indicating a reading reliability state of a specific partial image among the plurality of partial images indicates a predetermined unreliable state, a specific partial bit sequence detected from the specific partial image by the detection unit has an error.

4. The image processing apparatus according to claim 3 , wherein the determination unit determines the specific bit sequence on the basis of a first bit sequence and a second bit sequence, the first bit sequence being acquired by performing correction with an RS code without assuming that the plurality of partial bit sequences have errors, the second bit sequence being acquired by performing correction with an RS code on the assumption that, when the specific partial state information piece indicates the unreliable state, the specific partial bit sequence has an error.

5. The image processing apparatus according to claim 4 , wherein the determination unit determines whether or not the first bit sequence is determined as the specific bit sequence, on the basis of whether or not the first bit sequence is equal to the second bit sequence.

6. The image processing apparatus according to claim 5 , wherein the determination unit determines the first bit sequence as the specific bit sequence when the first bit sequence is equal to the second bit sequence.

7. The image processing apparatus according to claim 6 , wherein the determination unit does not determine the first bit sequence as the specific bit sequence when the first bit sequence is not equal to the second bit sequence.

8. The image processing apparatus according to claim 5 , wherein the determination unit does not determine the first bit sequence as the specific bit sequence when the first bit sequence is not equal to the second bit sequence.

9. An identification apparatus comprising:

a reading unit that reads an image from a medium having the image printed thereon, the image representing a specific bit sequence indicating identification information on any one of the medium and an electronic document printed on the medium;

an information acquisition unit that acquires a state information piece indicating a reading reliability state of the image read by the reading unit, the state information piece being assigned to each bit;

a detection unit that detects a bit sequence from the image read by the reading unit;

a determination unit that determines the specific bit sequence on the basis of the bit sequence detected by the detection unit and the state information piece acquired by the information acquisition unit; and

an output unit that outputs the identification information indicated by the specific bit sequence determined by the determination unit.

10. A method for determining a bit sequence comprising:

acquiring an image read from a medium having the image printed thereon, the image representing a specific bit sequence;

acquiring a state information piece indicating a reading reliability state of the image thus acquired, the state information piece being assigned to each bit;

detecting a bit sequence from the image thus acquired; and

determining the specific bit sequence on the basis of the bit sequence thus detected and the state information piece thus acquired.

11. A non-transitory computer readable medium storing a program that causes a computer to execute a process for determining a bit sequence, the process comprising:

acquiring an image read from a medium having the image printed thereon, the image representing a specific bit sequence;

acquiring a state information piece indicating a reading reliability state of the image thus acquired, the state information piece being assigned to each bit;

detecting a bit sequence from the image thus acquired; and

determining the specific bit sequence on the basis of the bit sequence thus detected and the state information piece thus acquired.