Device for injecting high energy laser beam into optical fiber

摘要

A method of halftoning a sample value from an intensity range including the steps of providing threshold arrays having threshold values from distinct ranges, one of which is the same as the intensity range, selecting the one with the same range as the intensity range and using the selected threshold array to halftone the sample value. Embodiments may include the following features. The threshold arrays are a first one having a first threshold value range and a second one having a second threshold value range that has more levels than does the first threshold value range. The first threshold array is built by scaling each value in the second threshold array down to the range of the first threshold array. The scaling is done by dividing by 257 and rounding up to the next whole number. The first threshold array has a threshold value range of zero to 255 and the second threshold array has a threshold value range of zero to 65535 or zero to 4095. Tone correction is performed using a transfer function mapping an 8-bit input sample value to a tone-corrected output sample value having more than 8 bits.