Image capture program for modified 1004x camera

The text of this website describes how to test the modifications using switches. The circuit diagram shows how to wire the interface board to a PC parallel port, allowing the computer to control exposures and capture images using a video capture card (I use a Hauppauge WinTV PCI card).

The iCatch program allows you to set exposure times, enable/disable the amplifier, and collect multiple exposures into a single AVI file. At present, iCatch is rather experimental. It works well on my machine (1.4 GHz Athlon, WinME) but hasn't been tested on other systems. Control of the parallel port is performed using 'outp' instructions which cause exceptions (crashes) under Windows NT/2000, unless special drivers are present.

I am making this program available so that those who do the hardware modifications can use it if they wish. I cannot make any claims as to its 'fitness for purpose', or take any responsibility for any problems it may cause. All I can say is that it works fine for me, and that I have made efforts to ensure that it ought to work on other compatible systems.

Please Note: iCatch is a program I have written for capturing astronomical images from a home-made camera. It is not related in any way to the icatch web cam. I am sorry, but I am unable to answer any queries concerning the icatch web cam.

To use iCatch, you first need to select a video driver under the 'options' menu. Once you've selected your capture card you need to set it to 640x480 mode, in the 'Options/Video Format' menu. You may also set 'Preview' or 'Overlay' modes.

In use, iCatch displays two windows. The one with the menu and toolbar shows the current view from the video camera. Normally this will be a 'live' signal when you are not integrating, which is useful for focussing etc. The other window shows the last long exposure to be captured.

To start a capture session, first ensure the camera is connected to the parallel port as well as to the capture card. Then select 'Capture/setup' to set the various capture options. You can control the exposure duration (in milliseconds), the pause between exposures, and the total number of exposures to take. You can also choose whether to use the amplifier switch - if used the amplifier will automatically switch on one second before the exposure ends, to allow it to stabilise. You can choose the name of the AVI file in which the exposures will be stored, and you can tell iCatch to automatically generate a unique filename by appending an incrementing number to the name you give it.

When you have filled in all the fields, you can start a capture session. You should hear the relays click in the camera as the exposure starts, and after the specified time they will click again and the 'snapshot' window should show the first exposure - which will also be stored in the AVI file.

If you want to view exposures without storing them (e.g. while focussing or framing your shots), you can click the 'pause' button (or select it from the 'capture' menu). To stop recording click the 'stop' button. It is possible to adjust the exposure times whilst capturing, but you should be careful not to press 'start capture' if already capturing (known bug). The actual capture (at the end of an exposure) is fairly CPU-intensive, so it's best not to be running other programs whilst capturing.

I have done my best to make iCatch compatible with other video drivers, but have been unable to test it (since I only have one capture card). As of pre-release version 0.03, it should work with image formats other than 24-bit RGB, which will help when using other drivers.

I've also made iCatch compatible with the 'stage 1' modification. If you set the capture size to 320x240 then iCatch will not try to re-interlace frames but instead will simply look for the brightest frame that arrives shortly after the exposure is ended, and store the frame to an AVI. If the capture size is 640x480 then iCatch will expect to be working with a 'full mod' camera, and will look for two exposed fields which it will reinterlace. If you have a 'full mod' then iCatch allows you to use it as a 'stage 1' camera, simply by setting capture size to 320x240. This gives the benefits of binning scanlines and results in a brighter, but smaller, image.

Compatibility with WinXP/NT/2000

iCatch was developed and tested under Windows ME. Windows XP/NT/2000 will not let iCatch access the parallel port unless you have previously installed a special driver to grant access to the hardware. There are various examples of this kind of driver, one of which is PortTalk/Allowio. You can find an example of the use of this driver at this location, or this one. Once you have installed a suitable driver and started iCatch appropriately, it should be able to access the port without generating an exception. However I can't (yet) guarantee that iCatch will work correctly with the video capture drivers under these operating systems. If anyone manages to successfully capture long exposures under XP/NT/2K, please let me know so I can update this information!


Download version 0.03 iCatch.zip (24Kb)...
iCatch version 0.07 for Hauppauge USB capture device (51Kb)...
iCatch version 0.07 for PCI capture cards (29Kb)...
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