Display medium and code reading method

A display medium comprising an information code, wherein

• the information code is displayed on the display medium,
• the information code is generated by combining a first code and a second code,
• in each of the first code and the second code, information is recorded by multiple cells arranged in a two-dimensional array,
• the information code includes:
• a light color cell;
• a dark color cell;
• a semi-light color cell having a color closer to the light color cell than to the dark color cell, the semi-light color cell being identified as the same as the light color cell in a reading of the first code and being identified as the dark color cell in a reading of the second code;
• and
• a semi-dark color cell having a color closer to the dark color cell than to the light color cell, the semi-dark color cell being identified as the same as the dark color cell in the reading of the first code and being identified as the light color cell in the reading of the second code, and
• the second code has a smaller size than the first code and is combined at a center of the first code.

A code reading method to be executed by at least one processor, the code reading method reading a second code from an information code, the information code being generated by combining a first code with the second code, in each of the first code and the second code, information being recorded by multiple cells arranged in a two-dimensional array, the code reading method comprising:

• determining a semi-light color cell, which has a color closer to a light color cell than to a dark color cell, as the dark color cell;
• determining a semi-dark color cell, which has a color closer to the dark color cell than to the light color cell, as the light color cell;
• and
• reading the second code by identifying two or more cells in the first code as one cell.

A code reading method to be executed by at least one processor, the code reading method reading a second code from an information code, the information code being generated by combining a first code with the second code, in each of the first code and the second code, information being recorded by multiple cells arranged in a two-dimensional array, the code reading method comprising:

• specifying a formation range of the second code, which is combined at a center of the first code;
• determining a semi-light color cell, which has a color closer to a light color cell than to a dark color cell among the cells in the formation range, as the dark color cell;
• and
• determining a semi-dark color cell, which has a color closer to the dark color cell than to the light color cell among the cells in the formation range, as the light color cell.