Maximum CMU width range

[Bomberofdoom]

Does anyone know the amount of pixels in the x axis of the camera(servos not moving)? From what I understand, Easyc has those values, but we're using MPLab.
Thanks. :)

[JBotAlan]

The answer is in Kevin Watson's "Bells and whistles" version of the camera code, in tracking.h:
// parameters for CMUcam2 with OV7620 camera module
#define IMAGE_WIDTH 159
#define IMAGE_HEIGHT 239

Those are in pixels.

Happy hacking,

JBot

[Tom Bottiglieri]

Also, you get about 60 degrees of sight in the wide direction.

[JBotAlan]

Also, you get about 60 degrees of sight in the wide direction.

Hmm, I think I measured it to be about 50 degrees last week...back to the drawing board for me...:(

Then again, my FOV measurements suggested that the longer dimension (the height) has a narrower FOV than the shorter dimension (the width). I went over my math a few times and had someone else check it over, so I'm pretty sure my measurements are OK.

I don't know; I'll take another look at it either tonight or tomorrow night.

JBot

[Bomberofdoom]

Huh, we had it 46.6 degrees....:confused:

Thanks again! :D

Does anyone know the exact(+- 5 degrees) width range?

[jdejoannis]

It probably depends a bit on how you measure the view angle.

And yes, the pixel dimensions 160x240, makes the camera's field of view taller than it is wide - unlike a TV screen.

Jason

[Alan Anderson]

..the pixel dimensions 160x240, makes the camera's field of view taller than it is wide - unlike a TV screen.

Check again. The width of 160 is in "half resolution" mode, with each reported pixel being twice as wide as it is tall. The actual aspect ratio is a perfectly TV-compatible 320x240.

[jdejoannis]

Check again. The width of 160 is in "half resolution" mode, with each reported pixel being twice as wide as it is tall. The actual aspect ratio is a perfectly TV-compatible 320x240.

I stand corrected. That is not mentioned in tracking.h. You found that in the CMU manufacturer's specs?

[Bomberofdoom]

So does anyone have the estimate? I'm not quite sure what the resolutions tell about the camera's width view.

[Kevin Watson]

Check again. The width of 160 is in "half resolution" mode, with each reported pixel being twice as wide as it is tall. The actual aspect ratio is a perfectly TV-compatible 320x240.Just to avoid some confusion here, Alan is correct when he says the imager used in the CMUcam2 (http://kevin.org/frc/OV7620_ds.pdf) is larger than the values found in tracking.h. To get reasonable update rates from the camera, the microcontroller down-samples the image to 160 x 240 and then does all operations on that smaller image.

-Kevin

[jdejoannis]

Which suggests that vertical, say height, calculations are more accurate.