System for, and method of, controlling illumination of direct part marking (DPM) targets to be read by image capture
AssigneeSymbol Technologies, Inc.
InventorsDuanfeng He, Eugene B. Joseph
Life of this patent
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Abstract
An array of pixels of a solid-state imaging sensor having a rolling shutter is sequentially exposed to capture images from an illuminated DPM target over successive frames for image capture by an imaging reader. The DPM target is illuminated at an elevated output power level for a fractional time period of a frame, and is not illuminated for at least a portion of a remaining time period of the frame for increased energy efficiency. Only a sub-array of the pixels is exposed during the fractional time period in which the DPM target is being illuminated at the elevated output power level.
Claims13
A control system for an imaging reader having an illuminating light assembly for illuminating a direct part marking (DPM) target with illumination light, and a solid-state imaging sensor for exposing an array of pixels over an imaging field of view to capture images from the illuminated DPM target over successive frames, the control system comprising:
- an illumination controller to control an output power level of the illumination light;
- and
- a main controller in communication with the imaging sensor and the illumination controller, the illumination controller to cause the illuminating light assembly to:
- illuminate the DPM target at a first output power level for a fractional time period of at least one of the frames;
- and
- illuminate the DPM target at a second output power level that is less than the first output power level for at least a portion of a remaining time period of the at least one frame, wherein:
- the imaging sensor is to detect a size of the DPM target;
- the fractional time period is proportional to the detected size of the DPM target;
- only a sub-array of the pixels of the array are exposed during the fractional time period;
- and
- the main controller is to control the imaging sensor to capture an image of the illuminated DPM target.
A method of illuminating a direct part marking (DPM) target with illumination light, and of exposing an array of pixels of a solid-state imaging sensor to capture images from the illuminated DPM target over successive frames, the method comprising:
- controlling an output power level of the illumination light;
- illuminating the DPM target at a first output power level for a fractional time period of at least one of the frames;
- detecting, using a logic circuit, a size of the DPM target;
- configuring, using the logic circuit, the fractional time period to be proportional to the detected size of the DPM target;
- illuminating the DPM target at a second output power level that is less than the first power level for at least a portion of a remaining time period of the at least one of the frames;
- exposing only a sub-array of the pixels of the array during the fractional time period;
- and
- capturing an image of the illuminated DPM target.
An apparatus, comprising:
- a light source to illuminate a target;
- a sensor to capture images over frames;
- a logic circuit configured to:
- cause the light source to illuminate the target with light at a first output power level for a fractional time period of a first one of the frames;
- detect a size of the target;
- configure the fractional time period to be proportional to the detected size of the target;
- cause the light source to illuminate the target at a second output power level that is less than the first power level for at least a portion of a remaining time period of the first one of the frames, wherein only a subset of pixels of the sensor are exposed during the fractional time period.
Dependencies are inferred from the claim text.