Questions and Answers as of 5 Mar.pdf

Ques ons and Answers As of 5 March 2024

RFQ FA910124QB022, Scien fic Cameras

Q1: The solicita on does not specify if a specific type of connec on is required to transfer the images from each camera to the computer. Is there a requirement in this regard? For example, is USB connec on ok? Please clarify.

A1: A specific type of connec on is not required; however, the data connec on must be ruggedized to support opera on in an industrial environment. Preferred connec on type is 1G or 10G ethernet (e.g.

using GenICam or GigE Vision standards), or a type of connec on that can be extended through an ethernet infrastructure (available line types are Cat 6/6a twisted pair, and single mode or mul mode fiber).

Q2: The solicita on is not clear on whether it is looking for an intensified camera, or not. Can you clarify if an intensified camera is required? It sounds from the men on of low‐level light and mul ple individual exposures to form one image that a gated intensified camera is required, but please clarify.

A2: An intensified camera is not required. Known types of cameras that can combine mul ple individual exposures before sensor readout are intensified cameras as well as non‐intensified interline cameras (e.g. Photometrics CoolSNAP K4). A known alterna ve approach is to combine the mul ple individual exposures a er readout (e.g. “frame adding” h ps://doi.org/10.1117/12.56091), though it is noted that this approach is difficult to do when combined with the requirements for high SNR (3.2 and 2.4) and maximum acquisi on me (3.3).

Q3: The solicita on does not specify sensi vity at specific wavelengths. Can you clarify what wavelengths will be imaged? Is there a specifica on on the sensor type? CCD, CMOS, or sCMOS?

A3: The wavelength range of the light is 600–700 nm. There is no requirement for sensor type.

Q4: It is men oned that at least a 1 megapixel (1024x1024) sensor is required, but it does not men on pixel size (and thus actual resolu on). Can you please clarify what is the requirement in terms of pixel size? Or if it does not ma er, please also clarify.

A4: The pixel size is not a required specifica on. The camera will be used in a standard imaging configura on, so the actual resolu on will be controlled by changing the objec ve lens focal length.

Q5: IAW the Technical Specifica on Sheet, “The Camera shall acquire a resul ng image that is a summa on of individual exposures”. Can you please explain "summa on of individual exposures" in more detail?

A5: In order to meet the SNR requirement, mul ple exposures of the same repea ng low light level event must be combined. The low‐level light event is between 5 to 100 photons per pixel per exposure (2.3), and the required data quality is an SNR of 50 or more (3.2). To meet the SNR requirement, even for an ideal detector (QE of unity and no electronics noise), you need at least 2500 photons per pixel before the shot noise is sufficiently low (using eqn 25 in EMVA Standard 1288, release 4.0 linear). Accumula ng

(or summing) mul ple exposures increases the effec ve amount of photons per pixel in the resul ng image.

Q6: IAW the Technical Specifica on Sheet, “Each low‐level light event corresponds to an illumina on level of approximately 5 to 100 photons per pixel per exposure”. Is it intended to use the camera with an Intensifier?

A6: The camera will not be coupled to an external intensifier. If an intensifier is required to meet other requirements, it will be packaged with the detector as an Intensified CCD/sCMOS camera.

Q7: IAW the Technical Specifica on Sheet, “The range of minimum to maximum signal in any image is at most 5x (excluding background)”. We do not understand what this parameter is asking, more detail is required.

A7: The intent of this requirement is to state the range of signal in the image, as an alterna ve to sta ng a dynamic range requirement. The phrasing of the requirement was done to clarify that the SNR requirement (in 3.2) applies as a minimum bound only on the signal (excluding background). Examples for the range stated in 2.3 are as follows:

For the minimum signal case: the detector will be exposed to a range of signal from 5 to 25 [photons per pixel per exposure]. The detector will need to be able to resolve the full range up to 25 without satura ng, and the SNR requirement is that for all signal levels at or above 5 will have an SNR greater than or equal to 50.

For the maximum signal case: the detector will be exposed to a range of signal from 20 to 100 [photons per pixel per exposure]. The detector will need to be able to resolve the full range up to 100 without satura ng, and the SNR requirement is that for all signal levels at or above 20 will have an SNR greater than or equal to 50.

Q8: IAW the Technical Specifica on Sheet, “The minimum SNR for the signal por on of the resul ng image is 50 (excluding background)”. Is it possible to give more detail?

A8: The intent of this requirement is to state the quality of the resul ng image. See A7 for more details.

Under ideal scaling (Poisson sta s cs), requirements for signal range (2.4) and minimum SNR (3.2) could be combined into a “nominal SNR at max signal” as 50*sqrt(5) = 112. However, this can be more restric ve than the requirement as it was stated, combined with the fact that we will not evaluate the SNR requirement at max signal; it will be evaluated at 1/5 of the max signal.

Q9: IAW the Technical Specifica on Sheet, “The maximum me to acquire the resul ng image is 14 seconds”. 14 seconds to acquire what? Can you please describe the an cipated workflow of 14s?

A9: The intent of this requirement is to state a maximum allowable collec on period for the resul ng image, because SNR scaling (in order to meet requirement 3.2) generally increases with more exposures.

The workflow is: the detector is exposed to each low level light event, which is repe vely pulsed with a period of 600 microseconds (2.1). The me to acquire in the requirement refers to the total me between start and end of data acquisi on. As an example: if an intensified or interline camera is used and collects 10,000 exposures using on‐chip accumula on, and the image readout to the computer is 50 milliseconds, then: me to acquire is 10,000*0.6 + 50 [ms] = 6.05 [s].