dB and Read Noise Calculators
The dynamic range of a camera can be expressed in decibels (dB), where the higher the dynamic range, the more gray levels that can be differentiated. However, the gray level values vary due to camera noise which must be taken into consideration when calculating actual dynamic range.
This calculator is designed to calculate the dynamic range when the full well capacity of the camera and read noise values are known. Alternatively, read noise can be calculated if the dynamic range and full well capacity are known.
Pseudo Global Frame Rate Calculator
sCMOS devices feature a “rolling shutter” where the exposure does not begin for the entire sensor at the same time. Instead, exposure and readout move from the top to the bottom of the sensor one line at a time. This architecture is a key reason why sCMOS cameras are significantly faster than (EM)CCD cameras which use a global shutter. A full description of rolling and global shutters can be found in our technical note.
However, there are circumstances where the rolling shutter and the “overlap” of sCMOS camera frames can be an issue. In this case, the “pseudo global” shutter mode should be used to imitate a global shutter.
When using this mode, the camera reads out slower. This calculator is designed to calculate the pseudo global frame rate based on the camera mode used and number of lines in the region of interest.
Note: The result produced by this calculator is theoretical, based on the line time in each mode
and the number of rows. Personal testing is always recommended.
CMOS vs EMCCD Photoelectron Signal Calculator
Comparing the signal level between two cameras can’t be done by simply comparing the gray level intensity because electron to gray level conversion varies greatly between camera modes, bit-depths and technology. For this reason, signal should always be compared in electrons to make sure the comparison is quantitatively accurate.
These calculators are designed to report electron values from gray level values for sCMOS and EMCCD cameras. All that’s needed are the bias/offset and gain values of the cameras being compared. These can be found in the camera Certificate of Performance or requested from the manufacturer. For simplicity, these calculators have been pre-loaded with typical values of some Teledyne Photometrics cameras.
Note: When using the “Select Camera” function, the result produced by these calculators will be based on typical bias/offset and gain values that may not exactly match the camera you have. For the best result, please obtain accurate values.
Signal to Noise Ratio Calculator
The Signal to Noise Ratio calculator provides you with a helpful tool to calculate the SNR of your CMOS or CCD camera set up. SNR characterizes the quality of a measurement. It is necessary to ensure that the signal level relative to noise is adequate to allow capture of accurate image information.
- Enter the Gain value for your camera. If you do not have it, please use the Mean Variance (Gain) calculator below
- Enter the grey level values (ADUs) for your signal.
- Enter the Read Noise for your camera. If you do not have it, please use the Read Noise calculator below.
- Enter the dark current value for your camera. This is normally available on the datasheet provided to you with the camera or on the Manufacturer’s website.
- Enter the exposure time of image.
- This will return with:
- The number of electrons in your signal
- The noise caused by dark current
- Total noise
- Signal to Noise Ratio
- Noise in grey scale values (ADUs)
Read Noise Calculator
The Read Noise calculator provides you with a helpful tool which allows you to calculate the read noise of your camera.
The read noise is a measure of the uncertainty associated with each image acquisition and is a function of the camera system.
- Subtract thw two bias images and save the results in 32-bit floating format.
- Calculate the Standard Deviation of the pixels in the image and enter it on the calculator.
- Enter the Gain value of the camera (e-/ADU)
If you do not have the gain value for your camera, use our Mean Variance (Gain) Calculator below
Dynamic Range Calculator
The Dynamic Range calculator provides you with a helpful tool which allows you to calculate the maximum dynamic range of your camera.
The Dynamic Range describes the ratio between the smallest and largest possible values the camera can quantitatively detect.
- Refer to the Datasheet or the Manufacturer’s website to find the Maximum Linear Full Well Capacity
- Use the Read Noise calculator above, enter the value of your read noise.
- If the calculator stops working, simply divide full-well capacity by read noise
Mean Variance Calculator
This single-point Mean Variance calculator will allow you to calculate the actual camera gain your point of measurement. The Mean Variance test is the industry standard for measuring and calculating the gain for every camera setup.
- Enter the average value of your Bias image.
- Enter the average values of your 2 image acquisitions.
- Subtract one acquisition from the other.
- Enter the value of the standard deviation between the pixels of the acquisition difference image.
- Click Calculate – This will return the value of the gain at your acquisition settings.