Q:  What is smear rejection ratio what's is the physical meaning of it . how do you measure it.

A: Smear is a effect created by imperfection of CCD sensor. Every video camera have a CCD sensor, due to imperfect of the CCD sensor, strong light enter CCD sensor will penetrate the photo resistance layer and create fag image. These unwanted image is called smear. the extend of a CCD camera can reject strong light is called Smear Rejection Ratio.

More :
Normal CCD sensor having 95 to 120 dB smear rejection ratio. During last 15 years it was evolve from  60 dB to 120 db. As the improvement can only be done by CCD sensor semiconductor foundry, a camera assembling firm have essentially no way to have hands on it. However this rule is now broken by Mintron Jaguar 63W1.
Jaguar 63W1 having a super high speed 20 MIPS DSP It will improve smear rejection ratio for 50 time (34 dB) and create 154dB superb smear rejection ratio that leading the world.
Although the actual way to achieve this goal is an proprietary industrial secrete of Mintron, however put it a laymen term the camera first take an image with shutter off  to build a smear only image in memory and then take second image with normal shutter speed that including wanted image and smear portion. Two image is then substrate by super speed DSP ad eliminate the smear.

Mintron's  test procedure for Smear Rejection Ratio

The formulas to calculate Smear Rejection Ratio by Mintron lab is as below  

S= 20 x log ( Ys / 200mV x 1/500 x 1/10 )

S =  Smear rejection ratio in term of dB
Ys = Video generate by strong light while electronics shutter is off  
200mV = Video generated by a standard object and back ground with lenses aperture set on F 5.6
500 = A very strong light that it 500 times larger  then normal situation is used to force creation of smear image
10 = Smear image is measured as 1/10 V of normal image.

for example if 200mV of smear image is measured under above test condition S will equal to 

S= 20 log ( 200mV/200mV x 1/500 x 1/10 ) = 20 log ( 1/5000 ) =20 ( -3.5 ) =70 dB

Mintron 63W1 having 154 dB Smear rejection ratio, means if the light increase for 35,000 times more 63W1  will  have as little smear as other camera.