Next-Gen Lane Tracker will be Hybrid

The camera topology consists of a single color CCD area array, capable of randomly addressable scan lines; a day/nite filter selector; a relay lens system; and the taking lens (front glass). Attached in close proximity and alignment will be the special spread-beam LASER illuminator (for night time). 

The daylight approach uses the first three active scan lines of a NTSC tri-color CCD area array. The image data from the array's R, G, B, outputs will be processed for Color Space Translation such that only HUE is extracted and used for White/Yellow Lines detection. 

This approach has among its properties, the exclusion of vehicle shadowing from the White/Yellow Line boundary detection problem. That is to say, the confusion between longitudinal /near parallel vehicle shadowing and White/Yellow Line edge boundaries has long been a problem requiring lots of DSP processor time.

A second property is that it utilizes ambient light, reducing the complexity of the LASER only based approach.

The night time line detection system utilizes the LASER only based approach found in the previous generation Lane Tracker.

In this approach, unlike the aforementioned first gen lane Tracker, the linear CCD array is replaced with the color R,G, B, area array of the daytime system.

An examination of the spectral plot of the color CCD array reveals a high sensitivity to the LASER wavelength, 790nm, in the RGB filter's NIR "pop-up" region.

The practical reasoning behind this approach are several: 
1) random intermittent full image views of the roadway scene could be captured; 
2) this would allow greater control on light integration time, i.e., several line times to multiple field intervals n x 16.667msec.
 

Conclusions
In the practical world, this may not present a problem, that is, distance between measurements "D"--worst case--would be: assuming a total of [23 (20 + 3 scanlines) x 63.5 usec = 1,465 usec frame rate] @ 60 MPH = 88'/sec = 1,056 "/sec = 26,822 mm/sec, then D = 1.547" /sample or 39.30 mm/sample.

1) Data Translation RGB - HSI Convertor DT7910 & ROM DT7971.

2) A real time SUM of Vectors circuit--analog or digital-- can also do the RGB - HSI conversion. 

Because this a radiometric not a photometric problem, the R G B inputs can have any weight, e.g.., equal weights R = 0.33, G = 0.33, B = 0.33.

• 1/3 " image area; 680 (H) x 500 (V) Active Elements
• 7.4 um Square Pixels
• Random Line Addressable
• 2000:1 Blooming Overload
• Dynamic Range >70 dB
• Dual Line Readout; 0 - 5 V Clocking Levels
• First Samples ~ March 97; Delivery ~ August, 97; Cost~ $ 62.00

Glen,

After speaking with our CCD group, I found out that our TC286 has the addressable line scan incorporated into it. The datasheet is in our 1996 Area Array Sensor databook, or I have attached an electronic copy if you don't have the book. It looks like we will have preliminary samples in March, with projected production in the August timeframe. It looks like the part will sell for somewhere around $62. Please refer to one of our authorized distributors for an exact quote or give us a call if you have further questions. Our phone number is (972) 644-5580.

Regards, Scott Johnson Product Information Center