Optical reading device

An optical reading device that reads a code attached to a workpiece, the optical reading device comprising:

• an illumination unit that emits light toward an area through which the workpiece passes;
• an imaging unit configured to receive the light emitted from the illumination unit and reflected from the area through which the workpiece passes, to generate a read image obtained by capturing an image of the area through which the workpiece passes, and to transfer the read image line by line;
• a pre-processing circuit that executes pre-processing of image data each time a predetermined number of lines of the image data is taken from the imaging unit, and calculates a characteristic amount indicating likelihood of the code for each area in the pre-processed image data based on a brightness value of each pixel in the pre-processed image data;
• a processor that acquires the characteristic amount calculated by the pre-processing circuit, determines a code candidate area in the read image based on the acquired characteristic amount, and executes a decoding process of the determined area to generate a decoding result;
• and
• an output unit that outputs the decoding result generated by the processor, wherein
• the pre-processing circuit executes edge detection processing on the image data taken from the imaging unit to generate edge data, and
• the characteristic amount is calculated by a combination of the edge data.