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SAMLight Manual > Backgrounds > Pixelmode

Pixelmode
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This chapter describes how the scanning of bitmaps works with the USC-1 and the RTC3 scanner card. The USC-1and RTC3 card provide a special mode for raster images (Bitmaps).

usc1_pixelmode1

Each pixel inside a bitmap has the same X and Y dimension dx,dy. dx and dy itself may be different. The bitmap consists of Nx pixels in X direction and Ny pixels in Y direction. Each pixel has a Grayvalue G (x,y) from 0 to 1 which is typically transformed to a Grayvalue range from 0 to 255.

The USC-1 and RTC3 raster modes allow to move the scanner across the bitmap by simultaneously modulating the laser control signal. Within this chapter it is assumed that the scanner movement is performed like shown below.

usc1_pixelmode2

The scanner starts at the lower left corner, moves over the first line (X-direction) with a defined speed, jumps back to the start of the second line and so on.

Special mode for RTC3 and RTC4 card: If the hardware mode is selected the RTC3 provides two different modes for the movement of the scanner itself. In Mode 0 (shown below for the first line) every pixel position is reached within one scanner step command.

usc1_pixelmode2b

Then the scanner stays at the pixel a certain time before it jumps to the next location. In Mode 1 the scanner moves over the pixels with a constant speed applying many microsteps between the single pixels. In the following scanner mode 1 (constant speed over the pixel line) is assumed.