NeoMedia Technologies, Inc (NEOM): JP & All, I have been..…..&#82...

Reply Private New

Replies (2) Next 10 Prev Next

Send PM Follow Ignore

Followers	27
Posts	707
Boards Moderated	0
Alias Born	03/16/2004

stock_raving_mad

Re: JPetroInc post# 97491

Monday, 11/13/2006 2:29:31 AM

Monday, November 13, 2006 2:29:31 AM

JP & All,

I have been..…..“Pondering”..…..this issue for a long time. I don’t want to be too much of a twit, but here are some things that I hope you will think about.

Regardless of what some may have argued on this thread, the number of pixels in the grid array of the camera sensor absolutely defines the ability of resolution. I worked an electronics engineering contract as R & D support with the Logitech camera division in the Silicon Valley area, and was involved with testing a number of camera sensors. One of the things that I learned at that job was that the number of pixels in the array is the most important factor in reproducing the intended picture.

If you have a digital camera that is capable of changing the resolution, you can do some simple experiments yourself, and also make comparisons to a low resolution camera phone if you have one. Try taking some photos of 1D bar codes on items around the house. You will notice that with the camera setting below 1Megapixels, photos of most 1D bar codes are not clear, depending the size of the bar code, and you will notice that some of the bars are blurred together. As you increase the camera setting to 3 Megapixals, and above you will notice that most photos of bar codes are clear enough, and you can see a clearer ability to discriminate/differentiate between the lines. An analogy might be like this; You have a ruler, or a yardstick that only has increments of feet, and inches, but you want to measure down to 1/32 of an inch. You can’t do it.

Yes, part of the clarity problem for camera phones is due to the lens. Camera cell phones are generally small, and this makes the lens focal length short, and the sensor is also physically smaller than the average digital camera too. Classically, a lens with a longer focal length will produce a clearer image. The problem is, it’s harder manufacture a quality lens with a short focal length. I believe this is why some of the newer, and better camera phones like the Nokia N93 have developed a swivel camera. This allows the camera lens to have a longer focal length. These camera sensors are also 3.2 Megapixels.
http://www.nokiausa.com/phones/N93/0,7747,,00.html

http://almanazir.typepad.com/almanazir/2006/11/why_is_a_camera_1.html

Another thing to try with a digital camera at different resolution settings; With a straightedge/ruler, draw three thin vertical lines with a fine black ball point pen from top to bottom on a piece of white 8.5” X 11” paper. Make the first two lines 1/8” apart, and the third about 1/16” or less from the second. Focus on the lines with the camera viewer. At vertical, the lines should look straight, and black. Tilt/rotate the camera a few degrees, and then up to 45 degrees so that the lines go at an angle/diagonal, and not straight up and down in the viewer, which becomes worst case, as you are focusing on the lines. When tilted a few degrees you will notice that the lines start to run in a stair step, particularly with the camera on the lower resolution settings. This happens because the camera array of individual pixel photo sensors, are physically lined up in rows, and columns, and the camera is showing you it’s limitations for reproducing the image. As you change the resolution setting, and increase the number of pixels, the stair steps get smaller, and the reproduction of the image gets better. You will also notice the colors of the stair steps changing when you are focusing on the lines before you take the photo. Normally the line would be black. This too is showing you the limitations of the camera sensor. This is the raw video. When you actually take the picture with a quality digital camera the stair steps will tend to disappear. The camera software averages this data to produce a more continuous photo. The line will be a little thicker than the image in the viewer, but this does not give you better resolution. It just makes the picture look better. If the lines are close enough they will run together. If you can copy the photos to a desk top computer you can amplify the photos, and clearly see the difference between the high, and low resolution photos.

I hope this experiment helps in understanding some of the limitations, and problems with digital photo sensors.

PS. There are many good web sites that talk about camera sensors.

You might find this comprehensive document on camera sensors informative. I like the explanation on color generation.

http://www.extremetech.com/article2/0,3973,15465,00.asp
http://www.extremetech.com/article2/0,1697,1157573,00.asp

Resolution.

http://www.extremetech.com/article2/0,1697,1157577,00.asp

To get an idea of what we are dealing with, download this datasheet of a cell phone camera sensor from Cypress Electronics to see the real thing that makes the camera work.

http://www.cypress.com/portal/server.pt?space=CommunityPage&control=SetCommunity&CommunityID...

PS. I have some thoughts about a Motorola/NeoMedia connection. Some posters have mentioned something like this before. I’m working on the dots.