REFRESH AND SOAK MODES

The MicronEye takes a picture much like any other camera. The MicronEye must have the proper amount of light to make the image develop properly. Too much light will overexpose the image, while too little light will underexpose the image. There are two ways to control the amount of light that the MicronEye sees. First, the available light can be increased or decreased. Second, the 'shutter speed' or 'exposure time' of the MicronEye may be increased or decreased. Exposure time is determined by how long the user allows the image sensor to be exposed to light without 'refreshing' the device. Simply put, refreshing the image sensor causes each cell in the image sensor to be written to 5 volts. If the image sensor is not continually refreshed, then the light focused on each cell causes the voltage in each cell to leak away at a rate proportionate to the intensity of the light. When the image sensor is not being refreshed, we say it is 'soaking.' Allowing the image sensor to soak for a longer period of time allows the MicronEye to 'see' better in dimmer light. When the REFRESH mode is selected, the MicronEye keeps the image sensor refreshed while it is sending an image. When SOAK mode is invoked, the MicronEye "soaks" while it is transmitting an image. When the MicronEye completes the transmission of an image, it automatically goes into 'soak' mode until another command is received. In REFRESH mode, exposure time is determined by how long the MicronEye is allowed to soak before it is sent a command to transmit the image. In SOAK mode, exposure time is equal to how long the MicronEye is allowed to soak plus the time required to transmit the image. Therefore, if the exposure time exceeds the transmission time, a great deal of time can be conserved by setting the SOAK mode. If the required exposure time is less than the transmission time, then the MicronEye will have to use the REFRESH mode to inhibit 'soaking' during transmission of the image, thereby restricting the exposure time to the time the MicronEye is allowed to soak between the transmission of each image. For example, if the desired exposure time was 600 milliseconds and the transmission time for an image was 120 milliseconds then the user could send the image with SOAK set and wait 480 milliseconds at the completion of each image transmission to create a 600 millisecond exposure time. Alternately, the user could send the image with REFRESH set and wait 600 milliseconds at the completion of each image transmission. Note that when the MicronEye is commanded to perform the SOAK command, it continuously reads cell location R0 C0, causing the OpticRAM internal circuitry to continuously refresh all cells in Row 0. Therefore, when using the SOAK command, the cells in Row 0 will not be light sensitive. This is not a problem when using 1 ARRAY mode because 1 ARRAY mode uses the lower array which is comprised of rows 128 to 255.