window -- adjust the contrast and dc offset of the current frame
The lookup table between the display frame values and the values sent to the display monitor is adjusted interactively to enhance the display. The mapping is linear with two adustable parameters; the intercept and the slope. The two values are set with the image display cursor in the two dimensional plane of the display. The horizontal position of the cursor sets the intercept or zero point of the transformation. Moving the cursor to the left lowers the zero point while moving the cursor to the right increases the zero point. The vertical position of the cursor sets the slope of the transformation. The middle of the display is zero slope (all frame values map into the same output value) while points above the middle have negative slope and points below the middle have positive slope. Positions near the middle have low contrast while positions near the top and bottom have very high contrast. By changing the slope from positive to negative the image may be displayed as positive or negative.
The interactive loop is exited by pressing any button on the cursor control.
cl> window Window the display and push any button to exit:
It may be necessary to execute FRAME before windowing.