MV1000 Application Notes


Interfacing the EG&G Reticon MD4013 camera to the MV-1000/1100 board

Overview

M-Vision-1000
The M-Vision-1000(MV-1000) is a monochrome digitizer board, which interfaces to the PCI bus. The MV-1000 product line includes a base board with analog camera support, a 3 Megabyte memory upgrade module (MV-1200), and a 32 bit digital interface module(MV-1100).

Interfacing to the MD4013 camera in digital mode requires the addition of the MV-1100 digital module. This module accepts the RS-422 differential video and timing signals from the MD4013 camera.

MD4013 Camera
The MD4013 camera from EG&G Reticon is a variable frame rate (up to 30 frames per second), 1024 x 1024, digital output, CCD camera. The output data is 8 bit digital, RS422 or TTL and the camera requires (15V and +5V DC power. The camera has three interface connectors - two DB-37 connectors which output 8 bit digital data and one 25 pin connector which supplies power to the camera head and provides access to analog data. The imaging area (sensor area) is a parallel array of 1024 columns (vertical CCD shift registers) each of which has 1024 picture elements. It also contains a horizontal shift register which splits the 1024 pixels in each vertical register into two sequential groups of 512 pixels each, which are output through two different ports (the two DB-37 connectors). The camera therefore has one sensor with two taps which read out each pixel in 8 bit digital format.

The 8 bit digital output out of the two taps on the sensor align themselves in an incontiguous byte stream as shown in Figure 1.


Figure 1


Therefore, in the MV-1000 memory, the data appears like the following Dword stream.

Byte 3102210201018...512
Byte 2135...511
Byte 1102310211019...513
Byte 0024...510

Figure 2
fs
The video needs to be realigned to appear contiguous and Mutech does provide a software program to achieve this (available upon request).

In standard use, the MD4013 camera is used with an optional shutter. The shutter when closed prevents light from falling on the photo elements of the device. The procedure is to open the shutter (using a Shutter Input signal), expose the photo elements for the desired duration, close the shutter - thereby preventing any more light from exposing the photo elements - and then finally providing a Frame Start Input (FST) signal to initiate device readout while the shutter is closed (i.e., when shutter input signal goes inactive). The readout begins at the actual instant that FST signal goes low. This prevents exposure during readout, which in turn prevents image smear. The Shutter Input signal and the FST signal will be provided by the MV-1100. Figure 3 illustrates signals at the camera end.


Figure 3


However, the camera that was used for testing purposes did not have an external shutter. In this case, the photo elements are constantly exposed to incident light - even during device readout. Device readout is fixed at approximately 30 msecs and is initiated by a FST signal from the MV-1000/1100. But a FST signal every 30 msecs would leave very little time to expose the photo elements to light. Therefore the FST signal must be provided at an interval farther apart than 30 msecs to allow the photo elements sufficient time to convert the light to charge. For instance, a FST, every 100 msecs. Figure 4 shows the FST signal.


Figure 4


The MD4013 camera outputs frame enable, line enable and pixel clock signals, in response to the FST signal.

Interfacing the MD4013 camera to the MV-1000/1100 board

Cable Connections
The J2 connector on the MV-1100 is a high density 51 slot female Airborne connector. The pinouts for this connector are listed in Appendix A of the MV-1100 User's guide and Technical Reference. This connector is connected via the MVCGEN (Rev. 4 - Mutech cable) to the top DB-37 connector on the MD4013 camera. The middle DB-37 connector is connected via a customer made cable to a DB-50 connector (which is attached through a ribbon cable to the J1 connector on the MV-1100, with Mutech cable MVCD-32). The bottom 25 pin connector, is connected to the camera base unit.


Figure 5


As explained above, the two DB-37 connectors output 8 bit digital data to the MV-1100 module. So in essenece, the two connectors are connected to the MV-1100 module as a 16 bit camera. The low byte (D0-D7) carries data from the first tap of the camera sensor and the high byte (D8-D15) carries data from the second.

Camera Configuration Files
From a software point of view, the concept of video acquisition from standard or non-standard cameras is based on the use of a Camera Configuration File. Camera "Config" files are ASCII files that hold all of the values relevant to the proper usage of a particular camera with the MV-1000.

Camera Configuration files for most commercially available cameras are included on a Mutech distribution diskette and by default are loaded into the directory ..\mv-1000\camcfg. All Mutech distribution software uses these Camera Config Files to set the board and chip registers into the correct state to work with a particular camera. The Camera Config File for the MD4013 in the three modes are mentioned below.
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Modes of Operation
The MD4013 can be used with the MV-1000/1100 in three different modes of operation - Free running mode, Triggered mode without shutter control and Triggered mode with shutter control.

Free running mode (without shutter control):
In this mode, a device called the timing generator on the MV-1000 is programmed to continuously generate vertical drive(V.D.) signal at the desired frame rate. The FST signal is automatically generated from V.D., by hardware on the MV-1100, to drive the MD4013. The camera configuration file for this mode is called MD4013FR.ini. This file has all the necessary information needed to start acquiring video in free running mode. One parameter of particular interest that needs to be checked is the Flag_ByPass_Counter, which must be set to 1 (this enables V.D. to drive FST).

Triggered Mode without shutter control:
In this mode, an external trigger starts a counter, which counts down from a number specified in the Counter_Value in the camera configuration file. Counter uses horizontal drive (H.D.), generated by the timing generator on the MV-1000, as the clock source to count down. Once the counter counts down, it will generate FST signal, which in turn will initiate frame read out from the MD4013 camera. The camera configuration file for this mode is called MD4013T.ini. The Flag_Bypass_Counter in the camera configuration file must be set to 0.

Triggered Mode with shutter control:
The shutter input and FST signals are provided by the MV-1100 in response to a trigger (either harware or software). The counter generates the shutter pulse which controls the exposure of the camera. The width of this pulse is controlled by the parameter Counter_Value in the camera configuration file. Each count in the Counter_Value corresponds to 25 msecs. Therefore a counter value of 0x8 corresponds to (8x25 msecs + 25 msecs = 225 msecs). The shutter input signal controls the opening and closing of the shutter and the FST signal causes readout of an entire frame. The camera configuration file for this mode is called MD4013TS.ini.

Figure 6 shows the signals in the case of triggered mode acquisition with shutter control.


Figure 6


Jumper Settings
The following jumper settings on the MV-1100 need to be checked:
JP10 = IN
JP11 = OUT
JP1 = BOTTOM
JP17 = RIGHT
In addition, for Triggered mode with shutter, JP15 = IN

DOS Utility - "Camtest.exe" The easiest way to verify proper functioning of the MD4013 camera with the MV-1000/1100 is through the DOS testing program "Camtest.exe". This program is included in the distribution diskette and is contained in the sub-directory "diag" under directory MV-1000.

To use Camtest.exe with the MD4013 camera in free running mode, type...
"camtest ..\camcfg\MD4013FR.ini" at the DOS prompt. This assumes that the camtest program is in the ..\diag directory and .ini files are in the ..\camcfg directory.

To use Camtest.exe with the MD4013 camera in triggered mode, type...
"camtest ..\camcfg\MD4013T.ini" at the DOS prompt.

To use Camtest.exe with the MD4013 camera in external trigger with shutter control mode, type...
"camtest ..\camcfg\MD4013TS.ini" at the DOS prompt.



MuTech Corp. July 1996
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