Camera in Grayscale

[Turing'sEgo]

Originally Posted by vladtheimpaled

If I'm not mistaken converting to grayscale reduces bandwidth because of the number of channels it transmits. With a standard rgb image, you have three channels per pixel. Each of these channels has value. For a grayscale image however you only have one channel. Now two extra channels on one pixel would not do much in terms of performance but once you have a few hundred extra it can especially when you try to get that image to send almost instantaneously .

You are absolutely right. Converting to grayscale would reduce the amount of data being sent over the network by a factor of 3 if you are sending raw data.

There are a number of ways to convert from rgb to grayscale, what language/computer vision library are you using?

[Greg McKaskle]

The LabVIEW WPILib has a function to set the Color Enable Property. True means color is enabled. False means the camera is grayscale. But the property is only supported for Axis cameras. JPEGs have a special encoding for grayscale images, and they are indeed smaller than color, but it isn't as simple as a threeX ratio.

As mentioned by others, there are other effective ways to reduce bandwidth. Image resolution reduces by X squared. Framerate by X.

Greg McKaskle

[dubiousSwain]

Originally Posted by Turing'sEgo

You are absolutely right. Converting to grayscale would reduce the amount of data being sent over the network by a factor of 3 if you are sending raw data.

But you're not sending raw data, you're sending an MJPG. Its lossy compression, and the difference between color and grayscale will be negligible compared to bumping up the compression a bit

[Ozuru]

Originally Posted by dubiousSwain

But you're not sending raw data, you're sending an MJPG. Its lossy compression, and the difference between color and grayscale will be negligible compared to bumping up the compression a bit

Exactly.

[Greg McKaskle]

I don't have time to do the side-by-side compare, but if you use an IP camera such as Axis and flip between color enable of true and false, you will see the difference. JPEG has a special definition for encoding Y only images and it is another way to reduce size. You are deciding whether you lose color and retain detail or lose color and detail by lowering compression. The other lever you can pull is the resolution or size of the image. The final lever is the framerate.

Experiment and make sure the drivers understand how to pull the levers for themselves. The default dashboard gives an LED indicator showing how their usage compares to the field limits. Also, I personally don't have much experience with the new radio and bandwidth limiting, but I expect that the radio will cause the equivalent of framerate limiting if you don't pull the levers to get your usage under the limit. I don't expect the cameras to hog bandwidth the way they were able to in past years.

Greg McKaskle