초록 ▼

An adaptive thresholder for processing image pixels. A portion of the image pixel line or lines is examined and the maximum and minimum pixels in the line portion determined. The maximum and minimum pixels are differenced, and the resulting difference signal compared to a constant representing the m

An adaptive thresholder for processing image pixels. A portion of the image pixel line or lines is examined and the maximum and minimum pixels in the line portion determined. The maximum and minimum pixels are differenced, and the resulting difference signal compared to a constant representing the minimum desired change in background level. Where the difference signal is larger, a new threshold is thereafter used. To determine the new threshold level, the difference signal is multiplied by a factor representing the amount of change in threshold for a given event and the result subtracted from the previously determined maximum pixel. The subtracted output is brought within predetermined maximum and minimum threshold constraints to provide the new threshold.

대표청구항 ▼

Apparatus for adaptively thresholding image pixels, comprising, in combination: (a) buffer means for storing a plurality of successive ones of said pixels including the pixel to be thresholded; (b) means for identifying the maximum pixel in said plurality of pixels; (c) means for identifying the min

Apparatus for adaptively thresholding image pixels, comprising, in combination: (a) buffer means for storing a plurality of successive ones of said pixels including the pixel to be thresholded; (b) means for identifying the maximum pixel in said plurality of pixels; (c) means for identifying the minimum pixel in said plurality of pixels; (d) first subtractor means for subtracting the output of said maximum pixel identifying means from said minimum pixel identifying means; (e) multiplier means for multiplying the output of said first subtractor means by a predetermined constant representing a desired change in threshold level; and (f) second subtractor means for subtracting the output of said multiplier means from said maximum pixel identifying means to provide a threshold for use in thresholding said one pixel.