Vinten Radamec Free-d - Manual (Page 35)

Vinten Broadcast Ltd free - d ™ Installation Manual V1.4.4
Page 35 of 46
The MSB of Target Flags (bit 7 of FH) is set for a valid target and cleared for
an invalid target. If the target is flagged as invalid its position data should be
ignored.
A.3.6 Type D6 & D7 - image data
The D6 and D7 messages are used for transferring image data from the free-
d™ unit. Each message contains data about a single target: requesting
message D6 causes data for the first target in the image to be transmitted and
requesting message D7 causes data for the next target in the image to be
transmitted. After data for the last target has been sent, the next message will
contain data for the first target, with a message type of D6 (whether the
request was for D6 or D7).
The messages contain 18 bytes as follows:
or Message type
Camera ID
Target Index (zero for message D6)
Target Number
X-Position in image
Y-Position in image
Error in X-Position
Error in Y-Position
Checksum
The X-Position and Y-Position are positive values in units of 1/256 pixels (i.e.
XH, XM is the integer part of the X-Position in pixels and XL is the fractional
part).
The Error values are signed and in units which depend on the lens calibration.
To obtain values in pixels the X-Error must be divided by X-Scale (see
message DA) and multiplied by 512. Similarly the Y-Error must be divided by
Y-Scale and multiplied by 512.
A.3.7 Type D8 - EEPROM data
The D8 message is used for transferring EEPROM data from or to the free-d™
unit. If a D8 message is sent to the free-d ™ unit the EEPROM is programmed
with the data supplied, and the free-d™ unit replies with a D8 message
containing the new data.
The message contains 21 bytes as follows:
Message type
Camera ID