Humminbird Side Imaging Forums

Side Imaging Forums => 997c SI, 998c SI & 999ci HD SI => Topic started by: cache22 on February 09, 2014, 08:03:04 AM

Title: Down Image ?
Post by: cache22 on February 09, 2014, 08:03:04 AM

May be a stupid question, but trying to visualize what is being shown below the water line in down imaging mode on 998.  Is it structure outside of down imaging sonar cone? and if so is only one side showingor both sides showing on overlap?? IE if you see an object, you know its distance from the 'ducer but not which side its on.

Title: Re: Down Image ?
Post by: rnvinc on February 09, 2014, 06:04:36 PM

The DI in the HB SI series units is a computer generated rendering of the data received by the SI piezo elements...(there is no "down pointing" piezo)...

The Di sonar in the HB Si units is a blend of both the left and right Si sonar:
*- take the right Si sonar and rotate it 90 degrees clockwise.
*- take the left Si sonar and flip it horizontally (mirror image) and then rotate it 90 degrees clockwise.
*- overlay the two images and you have a Di sonar image.

Rickie

Title: Re: Down Image ?
Post by: cache22 on February 09, 2014, 09:56:17 PM

Thanks Ricky,  I think I've got the picture  ;D.  So the narrow, medium, and wide settings just determine how big of slice of the sides are taken and folded around... right?

Title: Re: Down Image ?
Post by: rnvinc on February 10, 2014, 11:29:40 AM

The Narrow, Medium, and Wide settings are telling the unit how much of the SI data you actually want rendered into the DI view image....

(Similar to the Lower and Upper Range settings in the 2d Xpress menu...)

I think...:

*Wide DI setting is telling the unit to blend and display all the SI data...
*Medium DI setting (this one I'm not sure but probably a certain % of the left and right SI data)....
*Narrow DI setting is telling the unit to blend and display ONLY the echo targets common in both left SI and right SI...(which would basically be the overlap at the bottom of the SI beams)...

Rickie

Title: Re: Down Image ?
Post by: cache22 on February 10, 2014, 05:12:12 PM

Thanks, Rickie...... exactly what I was wanting to know!

Title: Re: Down Image ?
Post by: rnvinc on February 10, 2014, 05:28:22 PM

I'm going to make a minor retraction on part of my explaination...

I'm not entirely sure if the Wide DI setting encompasses ALL the SI data from the left and right SI data...but I think it does use echo data from pretty far out in the SI beams...(farther out than the Medium DI setting for sure...lol)...

The reason being the SI Range can be set to 240' left and right...and I doubt seriously the wide DI setting would show every echo in that 480' span...therefore my term "All" in the Wide DI setting is probably not correct...

Rickie

Title: Re: Down Image ?
Post by: Humminbird_Greg on February 12, 2014, 08:12:42 AM

Set the Lower Range menu down to 480 feet and it should Rickie.  Most of the time though the Lower Depth Range is automatically or manually set to something less than what the SI Range is set to.

Title: Re: Down Image ?
Post by: rnvinc on February 12, 2014, 12:03:37 PM

Quote from: Humminbird_Greg on February 12, 2014, 08:12:42 AM

Set the Lower Range menu down to 480 feet and it should Rickie.  Most of the time though the Lower Depth Range is automatically or manually set to something less than what the SI Range is set to.

Interesting...

Rickie