Hamamatsu CMOS Image Sensor Problem (S10834)

[zula]

Hi all,

We are designing a Xray image sensor for dental usage. We are using S10834 image sensor from hamamatsu and we are using XC3S50 fpfa to control S10834 and FT2232H to send pixels to PC. And we have a C# program to getting pixels from FT2232h and creating image on PC. And we are using PORT-X 3 as xray source.
We are able to getting image from sensor but the images quality really bad.
At this point we cannot define the problem and iam waiting your help.
ı attached the image that we are getting from sensor. Image is basic pcb.


Here is the S10834 datasheet;
**broken link removed**

Regards.

 

[keith1200rs]

It looks like solarization but that is a phenomenon if film photography. I am not sure how you create that in digital, but I suspect overloading of the ADC or corruption of the ADC data. You could try using a more predictable object to image. I am not sure how easy it would be to do with X-Rays but when dealing with cameras I would normally be using calibrated test charts with a grey scale, colour chart and resolution chart. Maybe there is something similar for testing/characterizing X-Ray cameras?

Keith

 

[zula]

hi keith,
i take some photo of basic things here is the pictures
this is screw


and there is a pin header;


S10834 has a 10bit ADC to measure XRAY level from photodiode and normally it gives me around 430 that is equally about ~2.2V. When there is a xray it reach up to just 460.

 

[Inti Innovations]

S10834 has a 10bit ADC to measure XRAY level from photodiode and normally it gives me around 430 that is equally about ~2.2V. When there is a xray it reach up to just 460.

I'd be worried. According to the datasheet the saturation voltage is around 1.2V ~ 300uGy. If you are getting 430 it means there is another Xray ON somewhere... or you are reading the ADC incorrectly..

 

[zula]

Hi Inti,

You are saying about image sensors saturation output. If you look photodiodes electrical characteristics it says saturation voltage is around 2.2V - 2.9V and value of ADC is 450.
There is two componenet inside of device. One of them image sensor and the other one is photodiode to measure xray level.

I think iam reading ADC correctly.

 

[Inti Innovations]

Yeah I think I misunderstood.
Did you try to take a 'picture' of the background without any X-ray source?

 

[zula]

yes we did and we get all bytes are zero.