Home » Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_39.ADF » F/+VGrab1
F/+VGrab1
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_39.ADF |
| Filename: | F/+VGrab1 |
| Read OK: | ✔ |
| File size: | 0986 bytes |
| Load address: | 2B204556 |
| Exec address: | 61724756 |
Duplicates
There are 2 duplicate copies of this file in the archive:
- Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_39.ADF » F/+VGrab1
- Personal collection » Acorn ADFS disks » Greaseweazled » dfs_box04_disk02b_eug_scripts.adf » PT4/F/+VGrab1
- Personal collection » Acorn hard disk » zipped_disks » elk03 » eug39/F/+VGrab1
File contents
Video Grabbing on the Beeb -------------------------- Written by Dominic Ford A couple of years back, EUG featured some digitalised images which had been submitted by Simon Piley. I am not quite sure of the origin of these images, but they were almost certainly digitalised on an Archimedes or PC, and then ported down to the Electron. I decided to have a go at doing something similar, except actually doing the digitalisation on a BBC. The idea I had was to put a video signal from a camera into a Beeb, and expect an image to appear on the screen. This project of mine is still very much in progress, and actually forms part of a rather larger project I am working on to get a Beeb to take a video image from a camera mounted on a rover, and use it to drive the rover to a desired destination. Currently, I am able to achieve a resolution of around 50x250 by grabbing a whole load of frames and compiling the results into one digital image. This does, of course, make the system useless for photographing moving objects, as it relies upon having a steady image for about a second while the grab is performed. Following the text of this article, there are a couple of sample grabs which I have done to show what the result look like. They don't look very good close-up, so stand back from the screen a bit to see the images. If you can't work out what they are (which you probably won't be able to) they are: 1. A BBC Micro keyboard (the function keys show up well...) 2. A building The quality of these grabs isn't that great compared to those done by Simon Piley, but remember - this is purely Beeb produce! I am currently working on a more sophisticated system which will take pictures at 128x250 resolution, which will look considerably better, AND it will draw all of the grab data from one frame, allowing moving objects to be grabbed. I'll send some better pictures when I've built my improved capture system, and will probably include some more detailed information of my rover project. The new capture system will involve fitting a PCB inside a BBC (and an Elk version might be possible as well), so it might be possible to produce a whole load of video grabber PCBs and sell them to EUG members along with software to do grabs (possibly #25 or so). Please do write into EUG if you are interested in the idea - essentially I'm going to see if there's any response before I start contacting any potential manufacturers.
00000000 56 69 64 65 6f 20 47 72 61 62 62 69 6e 67 20 6f |Video Grabbing o| 00000010 6e 20 74 68 65 20 42 65 65 62 0d 2d 2d 2d 2d 2d |n the Beeb.-----| 00000020 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------| 00000030 2d 2d 2d 2d 2d 0d 0d 57 72 69 74 74 65 6e 20 62 |-----..Written b| 00000040 79 20 44 6f 6d 69 6e 69 63 20 46 6f 72 64 0d 0d |y Dominic Ford..| 00000050 41 20 63 6f 75 70 6c 65 20 6f 66 20 79 65 61 72 |A couple of year| 00000060 73 20 62 61 63 6b 2c 20 45 55 47 20 66 65 61 74 |s back, EUG feat| 00000070 75 72 65 64 20 73 6f 6d 65 20 64 69 67 69 74 61 |ured some digita| 00000080 6c 69 73 65 64 20 69 6d 61 67 65 73 20 77 68 69 |lised images whi| 00000090 63 68 20 68 61 64 0d 62 65 65 6e 20 73 75 62 6d |ch had.been subm| 000000a0 69 74 74 65 64 20 62 79 20 53 69 6d 6f 6e 20 50 |itted by Simon P| 000000b0 69 6c 65 79 2e 20 49 20 61 6d 20 6e 6f 74 20 71 |iley. I am not q| 000000c0 75 69 74 65 20 73 75 72 65 20 6f 66 20 74 68 65 |uite sure of the| 000000d0 20 6f 72 69 67 69 6e 20 6f 66 20 74 68 65 73 65 | origin of these| 000000e0 0d 69 6d 61 67 65 73 2c 20 62 75 74 20 74 68 65 |.images, but the| 000000f0 79 20 77 65 72 65 20 61 6c 6d 6f 73 74 20 63 65 |y were almost ce| 00000100 72 74 61 69 6e 6c 79 20 64 69 67 69 74 61 6c 69 |rtainly digitali| 00000110 73 65 64 20 6f 6e 20 61 6e 20 41 72 63 68 69 6d |sed on an Archim| 00000120 65 64 65 73 20 6f 72 20 50 43 2c 0d 61 6e 64 20 |edes or PC,.and | 00000130 74 68 65 6e 20 70 6f 72 74 65 64 20 64 6f 77 6e |then ported down| 00000140 20 74 6f 20 74 68 65 20 45 6c 65 63 74 72 6f 6e | to the Electron| 00000150 2e 20 49 20 64 65 63 69 64 65 64 20 74 6f 20 68 |. I decided to h| 00000160 61 76 65 20 61 20 67 6f 20 61 74 20 64 6f 69 6e |ave a go at doin| 00000170 67 0d 73 6f 6d 65 74 68 69 6e 67 20 73 69 6d 69 |g.something simi| 00000180 6c 61 72 2c 20 65 78 63 65 70 74 20 61 63 74 75 |lar, except actu| 00000190 61 6c 6c 79 20 64 6f 69 6e 67 20 74 68 65 20 64 |ally doing the d| 000001a0 69 67 69 74 61 6c 69 73 61 74 69 6f 6e 20 6f 6e |igitalisation on| 000001b0 20 61 20 42 42 43 2e 20 54 68 65 0d 69 64 65 61 | a BBC. The.idea| 000001c0 20 49 20 68 61 64 20 77 61 73 20 74 6f 20 70 75 | I had was to pu| 000001d0 74 20 61 20 76 69 64 65 6f 20 73 69 67 6e 61 6c |t a video signal| 000001e0 20 66 72 6f 6d 20 61 20 63 61 6d 65 72 61 20 69 | from a camera i| 000001f0 6e 74 6f 20 61 20 42 65 65 62 2c 20 61 6e 64 20 |nto a Beeb, and | 00000200 65 78 70 65 63 74 0d 61 6e 20 69 6d 61 67 65 20 |expect.an image | 00000210 74 6f 20 61 70 70 65 61 72 20 6f 6e 20 74 68 65 |to appear on the| 00000220 20 73 63 72 65 65 6e 2e 0d 0d 54 68 69 73 20 70 | screen...This p| 00000230 72 6f 6a 65 63 74 20 6f 66 20 6d 69 6e 65 20 69 |roject of mine i| 00000240 73 20 73 74 69 6c 6c 20 76 65 72 79 20 6d 75 63 |s still very muc| 00000250 68 20 69 6e 20 70 72 6f 67 72 65 73 73 2c 20 61 |h in progress, a| 00000260 6e 64 20 61 63 74 75 61 6c 6c 79 20 66 6f 72 6d |nd actually form| 00000270 73 0d 70 61 72 74 20 6f 66 20 61 20 72 61 74 68 |s.part of a rath| 00000280 65 72 20 6c 61 72 67 65 72 20 70 72 6f 6a 65 63 |er larger projec| 00000290 74 20 49 20 61 6d 20 77 6f 72 6b 69 6e 67 20 6f |t I am working o| 000002a0 6e 20 74 6f 20 67 65 74 20 61 20 42 65 65 62 20 |n to get a Beeb | 000002b0 74 6f 20 74 61 6b 65 20 61 0d 76 69 64 65 6f 20 |to take a.video | 000002c0 69 6d 61 67 65 20 66 72 6f 6d 20 61 20 63 61 6d |image from a cam| 000002d0 65 72 61 20 6d 6f 75 6e 74 65 64 20 6f 6e 20 61 |era mounted on a| 000002e0 20 72 6f 76 65 72 2c 20 61 6e 64 20 75 73 65 20 | rover, and use | 000002f0 69 74 20 74 6f 20 64 72 69 76 65 20 74 68 65 0d |it to drive the.| 00000300 72 6f 76 65 72 20 74 6f 20 61 20 64 65 73 69 72 |rover to a desir| 00000310 65 64 20 64 65 73 74 69 6e 61 74 69 6f 6e 2e 20 |ed destination. | 00000320 43 75 72 72 65 6e 74 6c 79 2c 20 49 20 61 6d 20 |Currently, I am | 00000330 61 62 6c 65 20 74 6f 20 61 63 68 69 65 76 65 20 |able to achieve | 00000340 61 0d 72 65 73 6f 6c 75 74 69 6f 6e 20 6f 66 20 |a.resolution of | 00000350 61 72 6f 75 6e 64 20 35 30 78 32 35 30 20 62 79 |around 50x250 by| 00000360 20 67 72 61 62 62 69 6e 67 20 61 20 77 68 6f 6c | grabbing a whol| 00000370 65 20 6c 6f 61 64 20 6f 66 20 66 72 61 6d 65 73 |e load of frames| 00000380 20 61 6e 64 0d 63 6f 6d 70 69 6c 69 6e 67 20 74 | and.compiling t| 00000390 68 65 20 72 65 73 75 6c 74 73 20 69 6e 74 6f 20 |he results into | 000003a0 6f 6e 65 20 64 69 67 69 74 61 6c 20 69 6d 61 67 |one digital imag| 000003b0 65 2e 20 54 68 69 73 20 64 6f 65 73 2c 20 6f 66 |e. This does, of| 000003c0 20 63 6f 75 72 73 65 2c 20 6d 61 6b 65 0d 74 68 | course, make.th| 000003d0 65 20 73 79 73 74 65 6d 20 75 73 65 6c 65 73 73 |e system useless| 000003e0 20 66 6f 72 20 70 68 6f 74 6f 67 72 61 70 68 69 | for photographi| 000003f0 6e 67 20 6d 6f 76 69 6e 67 20 6f 62 6a 65 63 74 |ng moving object| 00000400 73 2c 20 61 73 20 69 74 20 72 65 6c 69 65 73 20 |s, as it relies | 00000410 75 70 6f 6e 0d 68 61 76 69 6e 67 20 61 20 73 74 |upon.having a st| 00000420 65 61 64 79 20 69 6d 61 67 65 20 66 6f 72 20 61 |eady image for a| 00000430 62 6f 75 74 20 61 20 73 65 63 6f 6e 64 20 77 68 |bout a second wh| 00000440 69 6c 65 20 74 68 65 20 67 72 61 62 20 69 73 20 |ile the grab is | 00000450 70 65 72 66 6f 72 6d 65 64 2e 0d 0d 46 6f 6c 6c |performed...Foll| 00000460 6f 77 69 6e 67 20 74 68 65 20 74 65 78 74 20 6f |owing the text o| 00000470 66 20 74 68 69 73 20 61 72 74 69 63 6c 65 2c 20 |f this article, | 00000480 74 68 65 72 65 20 61 72 65 20 61 20 63 6f 75 70 |there are a coup| 00000490 6c 65 20 6f 66 20 73 61 6d 70 6c 65 20 67 72 61 |le of sample gra| 000004a0 62 73 0d 77 68 69 63 68 20 49 20 68 61 76 65 20 |bs.which I have | 000004b0 64 6f 6e 65 20 74 6f 20 73 68 6f 77 20 77 68 61 |done to show wha| 000004c0 74 20 74 68 65 20 72 65 73 75 6c 74 20 6c 6f 6f |t the result loo| 000004d0 6b 20 6c 69 6b 65 2e 20 54 68 65 79 20 64 6f 6e |k like. They don| 000004e0 27 74 20 6c 6f 6f 6b 20 76 65 72 79 0d 67 6f 6f |'t look very.goo| 000004f0 64 20 63 6c 6f 73 65 2d 75 70 2c 20 73 6f 20 73 |d close-up, so s| 00000500 74 61 6e 64 20 62 61 63 6b 20 66 72 6f 6d 20 74 |tand back from t| 00000510 68 65 20 73 63 72 65 65 6e 20 61 20 62 69 74 20 |he screen a bit | 00000520 74 6f 20 73 65 65 20 74 68 65 20 69 6d 61 67 65 |to see the image| 00000530 73 2e 20 49 66 0d 79 6f 75 20 63 61 6e 27 74 20 |s. If.you can't | 00000540 77 6f 72 6b 20 6f 75 74 20 77 68 61 74 20 74 68 |work out what th| 00000550 65 79 20 61 72 65 20 28 77 68 69 63 68 20 79 6f |ey are (which yo| 00000560 75 20 70 72 6f 62 61 62 6c 79 20 77 6f 6e 27 74 |u probably won't| 00000570 20 62 65 20 61 62 6c 65 20 74 6f 29 0d 74 68 65 | be able to).the| 00000580 79 20 61 72 65 3a 0d 0d 31 2e 20 41 20 42 42 43 |y are:..1. A BBC| 00000590 20 4d 69 63 72 6f 20 6b 65 79 62 6f 61 72 64 20 | Micro keyboard | 000005a0 28 74 68 65 20 66 75 6e 63 74 69 6f 6e 20 6b 65 |(the function ke| 000005b0 79 73 20 73 68 6f 77 20 75 70 20 77 65 6c 6c 2e |ys show up well.| 000005c0 2e 2e 29 0d 32 2e 20 41 20 62 75 69 6c 64 69 6e |..).2. A buildin| 000005d0 67 0d 0d 54 68 65 20 71 75 61 6c 69 74 79 20 6f |g..The quality o| 000005e0 66 20 74 68 65 73 65 20 67 72 61 62 73 20 69 73 |f these grabs is| 000005f0 6e 27 74 20 74 68 61 74 20 67 72 65 61 74 20 63 |n't that great c| 00000600 6f 6d 70 61 72 65 64 20 74 6f 20 74 68 6f 73 65 |ompared to those| 00000610 20 64 6f 6e 65 20 62 79 0d 53 69 6d 6f 6e 20 50 | done by.Simon P| 00000620 69 6c 65 79 2c 20 62 75 74 20 72 65 6d 65 6d 62 |iley, but rememb| 00000630 65 72 20 2d 20 74 68 69 73 20 69 73 20 70 75 72 |er - this is pur| 00000640 65 6c 79 20 42 65 65 62 20 70 72 6f 64 75 63 65 |ely Beeb produce| 00000650 21 20 49 20 61 6d 20 63 75 72 72 65 6e 74 6c 79 |! I am currently| 00000660 0d 77 6f 72 6b 69 6e 67 20 6f 6e 20 61 20 6d 6f |.working on a mo| 00000670 72 65 20 73 6f 70 68 69 73 74 69 63 61 74 65 64 |re sophisticated| 00000680 20 73 79 73 74 65 6d 20 77 68 69 63 68 20 77 69 | system which wi| 00000690 6c 6c 20 74 61 6b 65 20 70 69 63 74 75 72 65 73 |ll take pictures| 000006a0 20 61 74 20 31 32 38 78 32 35 30 0d 72 65 73 6f | at 128x250.reso| 000006b0 6c 75 74 69 6f 6e 2c 20 77 68 69 63 68 20 77 69 |lution, which wi| 000006c0 6c 6c 20 6c 6f 6f 6b 20 63 6f 6e 73 69 64 65 72 |ll look consider| 000006d0 61 62 6c 79 20 62 65 74 74 65 72 2c 20 41 4e 44 |ably better, AND| 000006e0 20 69 74 20 77 69 6c 6c 20 64 72 61 77 20 61 6c | it will draw al| 000006f0 6c 20 6f 66 0d 74 68 65 20 67 72 61 62 20 64 61 |l of.the grab da| 00000700 74 61 20 66 72 6f 6d 20 6f 6e 65 20 66 72 61 6d |ta from one fram| 00000710 65 2c 20 61 6c 6c 6f 77 69 6e 67 20 6d 6f 76 69 |e, allowing movi| 00000720 6e 67 20 6f 62 6a 65 63 74 73 20 74 6f 20 62 65 |ng objects to be| 00000730 20 67 72 61 62 62 65 64 2e 0d 0d 49 27 6c 6c 20 | grabbed...I'll | 00000740 73 65 6e 64 20 73 6f 6d 65 20 62 65 74 74 65 72 |send some better| 00000750 20 70 69 63 74 75 72 65 73 20 77 68 65 6e 20 49 | pictures when I| 00000760 27 76 65 20 62 75 69 6c 74 20 6d 79 20 69 6d 70 |'ve built my imp| 00000770 72 6f 76 65 64 20 63 61 70 74 75 72 65 20 73 79 |roved capture sy| 00000780 73 74 65 6d 2c 0d 61 6e 64 20 77 69 6c 6c 20 70 |stem,.and will p| 00000790 72 6f 62 61 62 6c 79 20 69 6e 63 6c 75 64 65 20 |robably include | 000007a0 73 6f 6d 65 20 6d 6f 72 65 20 64 65 74 61 69 6c |some more detail| 000007b0 65 64 20 69 6e 66 6f 72 6d 61 74 69 6f 6e 20 6f |ed information o| 000007c0 66 20 6d 79 20 72 6f 76 65 72 0d 70 72 6f 6a 65 |f my rover.proje| 000007d0 63 74 2e 20 54 68 65 20 6e 65 77 20 63 61 70 74 |ct. The new capt| 000007e0 75 72 65 20 73 79 73 74 65 6d 20 77 69 6c 6c 20 |ure system will | 000007f0 69 6e 76 6f 6c 76 65 20 66 69 74 74 69 6e 67 20 |involve fitting | 00000800 61 20 50 43 42 20 69 6e 73 69 64 65 20 61 20 42 |a PCB inside a B| 00000810 42 43 0d 28 61 6e 64 20 61 6e 20 45 6c 6b 20 76 |BC.(and an Elk v| 00000820 65 72 73 69 6f 6e 20 6d 69 67 68 74 20 62 65 20 |ersion might be | 00000830 70 6f 73 73 69 62 6c 65 20 61 73 20 77 65 6c 6c |possible as well| 00000840 29 2c 20 73 6f 20 69 74 20 6d 69 67 68 74 20 62 |), so it might b| 00000850 65 20 70 6f 73 73 69 62 6c 65 20 74 6f 0d 70 72 |e possible to.pr| 00000860 6f 64 75 63 65 20 61 20 77 68 6f 6c 65 20 6c 6f |oduce a whole lo| 00000870 61 64 20 6f 66 20 76 69 64 65 6f 20 67 72 61 62 |ad of video grab| 00000880 62 65 72 20 50 43 42 73 20 61 6e 64 20 73 65 6c |ber PCBs and sel| 00000890 6c 20 74 68 65 6d 20 74 6f 20 45 55 47 20 6d 65 |l them to EUG me| 000008a0 6d 62 65 72 73 0d 61 6c 6f 6e 67 20 77 69 74 68 |mbers.along with| 000008b0 20 73 6f 66 74 77 61 72 65 20 74 6f 20 64 6f 20 | software to do | 000008c0 67 72 61 62 73 20 28 70 6f 73 73 69 62 6c 79 20 |grabs (possibly | 000008d0 23 32 35 20 6f 72 20 73 6f 29 2e 20 50 6c 65 61 |#25 or so). Plea| 000008e0 73 65 20 64 6f 20 77 72 69 74 65 20 69 6e 74 6f |se do write into| 000008f0 0d 45 55 47 20 69 66 20 79 6f 75 20 61 72 65 20 |.EUG if you are | 00000900 69 6e 74 65 72 65 73 74 65 64 20 69 6e 20 74 68 |interested in th| 00000910 65 20 69 64 65 61 20 2d 20 65 73 73 65 6e 74 69 |e idea - essenti| 00000920 61 6c 6c 79 20 49 27 6d 20 67 6f 69 6e 67 20 74 |ally I'm going t| 00000930 6f 20 73 65 65 20 69 66 0d 74 68 65 72 65 27 73 |o see if.there's| 00000940 20 61 6e 79 20 72 65 73 70 6f 6e 73 65 20 62 65 | any response be| 00000950 66 6f 72 65 20 49 20 73 74 61 72 74 20 63 6f 6e |fore I start con| 00000960 74 61 63 74 69 6e 67 20 61 6e 79 20 70 6f 74 65 |tacting any pote| 00000970 6e 74 69 61 6c 0d 6d 61 6e 75 66 61 63 74 75 72 |ntial.manufactur| 00000980 65 72 73 2e 0d 0d |ers...| 00000986
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