Method of optimizing focus plane position of imaging scanner

A method comprising:

• projecting a light pattern towards a target object;
• detecting light returned from the target object through an imaging lens arrangement with an imaging sensor to capture at least a first slit-frame-image and a second slit-frame-image, the imaging sensor having rows of photosensitive elements arranged in a matrix, wherein each of the first slit-frame-image and the second slit-frame-image has pixels located in no more than 32 rows of photosensitive elements in the matrix;
• changing the position of the focus plane of the imaging lens arrangement to make the average position of the focus plane of the imaging lens arrangement during the capture of the first slit-frame-image different from the average position of the focus plane of the imaging lens arrangement during the capture of the second slit-frame-image;
• determining an optimized position of the focus plane of the imaging lens arrangement, with said determining including processing at least the first slit-frame-image and the second slit-frame-image;
• detecting light returned from the target object through the imaging lens arrangement with the imaging sensor during a main frame exposure time period to capture an image of a barcode when the position of the focus plane of the imaging lens arrangement during at least part of said main frame exposure time period is maintained at the optimized position of the focus plane as previously determined;
• and
• processing the image of the barcode to decode the barcode.

A method comprising:

• projecting a light pattern towards a target object;
• detecting light returned from the target object through an imaging lens arrangement with an imaging sensor to capture multiple slit-frame-images, the imaging sensor having rows of photosensitive elements arranged in a matrix, wherein each of the multiple slit-frame-images has pixels located in no more than 32 rows of photosensitive elements in the matrix;
• changing the position of the focus plane of the imaging lens arrangement;
• determining an optimized position of the focus plane of the imaging lens arrangement, with said determining including processing at least some of the multiple slit-frame-images, and wherein the average position of the focus plane of the imaging lens arrangement during the capture of at least one of the multiple slit-frame-images has a value different from the average position of the focus plane of the imaging lens arrangement during the capture of another one of the multiple slit-frame-images;
• and
• detecting light returned from the target object through the imaging lens arrangement with the imaging sensor during a main frame exposure time period to capture an image of a barcode when the position of the focus plane of the imaging lens arrangement during at least part of said main frame exposure time period is maintained at the optimized position of the focus plane as previously determined;
• and
• processing the image of the barcode to decode the barcode.