The GREYSCREEN program is a takeoff from the GREYPIC program. However, the GREYSCREEN program attempts to show pseudo-greytone images on the screen. Because the Apple has no true shades of grey, we must simulate the grey by alternating black and white pixels. As in the GREYPIC program the MicronEye uses different exposure times to determine shades of grey.
The GREYSCREEN program uses two different exposure times which are controlled from the keyboard. If a pixel from the camera is white for both exposure times, then the wide pixel on the screen is all white. If a pixel from the camera is black for both exposure times, then the wide pixel on the screen is all black. If a pixel from the camera is white at one exposure time, and black at the other, then one side of the wide pixel on the screen will be black and the other will be white.
As in the GREYPIC program, the screen is divided into three partitions. These partitions are selectable from the keyboard and allow a composite image to be created on the screen which may be printed or stored for later retrieval or manipulation.
The concept utilized by the GREYSCREEN program is easily transferrable to other computers. Computers such as the IBM PC, Commodore 64, and TRS-80 Color Computer have implemented a medium resolution graphics mode which uses two bits to represent the pixel color on the screen. At the very least, black, white, light grey, and dark grey are available for creating an image. The obvious advantage over the Apple is the fact that real shades of grey are available for display.
The real-time commands available for use with the GREYSCREEN program are:
Here's The BASIC GREYSCREEN SOURCE CODE