Symbol reading device, symbol reading method and program recording medium to control focus based on size of captured symbol
Disclosed is a symbol reading device including: an imaging section to capture a symbol and generate an image; a detecting section to detect a size of the symbol; a judging section to judge large or small by comparing the size of the symbol to a pre-set value; a focus movement controlling section to move a focus position of the imaging section to a predetermined position of a farther side when the size of the symbol is smaller than the pre-set value as a result of the judgment, and to move a focus position of the imaging section to a predetermined position of a closer side when the size of the symbol is larger than the pre-set value as a result of the judgment; and an analyzing section to analyze symbol data corresponding to the symbol at a focus position moved by the focus movement controlling section.
1. A symbol reading device comprising:
an imaging section to capture a symbol and generate a captured image;
a detecting section to detect a size of the symbol from the captured image generated by the imaging section;
a judging section to judge between large and small by comparing the size of the symbol detected by the detecting section to a pre-set value;
a focus movement controlling section to move a focus position of the imaging section to (i) a predetermined position of a farther side when the size of the symbol is smaller than the pre-set value as a result of the judgment by the judging section, and (ii) a predetermined position of a closer side when the size of the symbol is larger than the pre-set value as a result of the judgment by the judging section; and
an analyzing section to analyze symbol data corresponding to the symbol from the captured image generated by the imaging section at the focus position moved to by the focus movement controlling section;
wherein the detecting section detects the size of the symbol based on a portion showing a coordinate position, the portion being included in the captured image.
2. The symbol reading device according to claim 1 , wherein:
the pre-set value is at least two different values; and
the focus movement controlling section moves the focus position of the imaging section to the predetermined position of the farther side when the size of the symbol is smaller than a smaller value of the two different values as a result of the judgment by the judging section, and moves the focus position of the imaging section to the predetermined position of the closer side when the size of the symbol is larger than a larger value of the two different values as a result of the judgment by the judging section.
3. The symbol reading device according to claim 1 , wherein the symbol is one of a one dimensional barcode and a two dimensional code.
4. A non-transitory computer readable recording medium having a program stored thereon which is readable by a computer of a symbol reading device, wherein the program controls the computer to perform functions comprising:
detecting a size of a symbol from a captured image generated by an imaging section;
judging between large and small by comparing the detected size of the symbol to a pre-set value;
controlling to move a focus position of the imaging section to (i) a predetermined position of a farther side when the size of the symbol is smaller than the pre-set value as a result of the judgment, and (ii) a predetermined position of a closer side when the size of the symbol is larger than the pre-set value as a result of the judgment; and
analyzing symbol data corresponding to the symbol from the captured image generated by the imaging section at the focus position moved to by the controlling;
wherein the size of the symbol is detected based on a portion showing a coordinate position, the portion being included in the captured image.
5. A symbol reading method performed by a computer of a symbol reading device, the method comprising:
detecting a size of a symbol from a captured image generated by an imaging section;
judging between large and small by comparing the detected size of the symbol to a pre-set value;
controlling to move a focus position of the imaging section to (i) a predetermined position of a farther side when the size of the symbol is smaller than the pre-set value as a result of the judgment, and (ii) a predetermined position of a closer side when the size of the symbol is larger than the pre-set value as a result of the judgment; and
analyzing symbol data corresponding to the symbol from the captured image generated by the imaging section at a focus position moved to by the controlling;
wherein the size of the symbol is detected based on a portion showing a coordinate position, the portion being included in the captured image.
6. The symbol reading method according to claim 5 , wherein:
the pre-set value is at least two different values; and
movement is controlled to move the focus position of the imaging section to the predetermined position of the farther side when the size of the symbol is smaller than a smaller value of the two different values as a result of the judgment, and to move the focus position of the imaging section to the predetermined position of the closer side when the size of the symbol is larger than a larger value of the two different values as a result of the judgment.
7. The symbol reading method according to claim 5 , wherein the symbol is one of a one dimensional barcode and a two dimensional code.