Since its release in 2011, the Flash 4.0 series has been the flagship product in the sCMOS camera market and has been widely used in various applications. Hamamatsu has never stopped pursuing the pinnacle and has been continuously improving Flash 4.0 to meet the needs of users. Flash 4.0 V3 not only improves pixel uniformity and USB 3.0 shooting frame rate, but also adds many special features and options to meet the needs of various applications.

　QC-CMOS: Improving Pixel Uniformity

In quantitative imaging for scientific research, the uniformity of the camera background and the uniformity of each pixel's response to light are crucial. Flash 4.0 V3 has reduced the camera's DSNU (Dark Signal Non Uniformity) and PRNU (Photo Response Non Uniformity), resulting in significant improvements in pixel uniformity, making it more suitable for applications such as super-resolution imaging (such as STORM, PALM, localization microscopy, etc.) that are more focused on quantitative imaging.

DSNU reflects the uniformity of the camera background, and the typical value of DSNU for Flash 4.0 V3 is 0.3 e rms. The left and right images in the following figure are the average of 10 original images taken for the same sample; The contrast ratio is adjusted to 98-106 (the offset of Flash 4.0 is 100, and in the absence of a signal, the theoretical grayscale value of the pixel is 100). From the image, it can be seen that the background of Flash 4.0 V3 is relatively more uniform compared to the former.

PRNU reflects the uniformity of the light response of each pixel in the camera. The typical PRNU value of Flash 4.0 V3 is 0.3% rms when the signal intensity is 700 electrons (approximately 1500 grayscale values); When the signal strength is 15000 electrons (equivalent to approximately 30000 grayscale values), the typical PRNU value is 0.06% rms.

In addition, the linearity of Flash 4.0 V3 has also been improved, with a linear error of 0.5% throughout the entire dynamic range; For low light detection, for example, when the signal strength is 500 electrons (converted to a grayscale value of about 1100), the linear error is as low as 0.2%. In other words, in this type of low light detection, the linear error is as low as 1 electron.

　QC-CMOS: Improving Pixel Uniformity

One major advantage of sCMOS in many applications, such as optical imaging, is its ability to provide high frame rates and resolutions while ensuring signal-to-noise ratio. But the huge amount of data that comes with it often causes difficulties in data processing. Flash 4.0 V3 provides 16 bit/12 bit/8 bit data output options to help reduce data volume in appropriate situations. For example, at 16 bit output, the data volume of Flash 4.0 V3 at 100 frames per second is approximately 800 MB/s; If 8-bit output is used, the data volume can be reduced to about 400 MB/s.

Simple pixel depth reduction can cause the loss of some subtle light and dark information in the image, which means that signals that could be distinguished at high pixel depths (such as 3 bits in image B and 16 bits in image E) may not be distinguishable due to simple pixel depth reduction (such as 2 bits in image C and 8 bits in image F). Especially in weak signal imaging, the grayscale variation of the signal may be limited to a small range, so when the bit depth decreases, the originally different grayscale values will be compressed into one grayscale, resulting in the loss of detailed information (such as from Figure B to Figure C and from Figure E to Figure F).

In order to make the 8-bit and 12 bit pixel depth options practical, it is crucial to ensure image quality as much as possible. Flash4.0 V3 allows for the selection of the grayscale variation range of an image, so that the converted grayscale values can be distributed over a wide range in the degraded grayscale space, ensuring image quality as much as possible (such as from Figure B to Figure A and from Figure E to Figure D).

USB 3.0 version: higher speed

The Flash 4.0 series introduced two freely replaceable data interfaces, CameraLink and USB 3.0, to connect to computers in the V2 era. CameraLink's frame rate can achieve a full frame rate of 100 frames per second; Although USB 3.0 is slightly slower when connected, it is easy to connect (even directly to a laptop), cost-effective, and can be directly upgraded to the high-speed CameraLink version at the user's location as needed (only the data cable and data acquisition card need to be replaced, and the camera head does not need to be moved), so it has been widely welcomed in the market. In Flash 4.0 V3, the speed of USB 3.0 connection has been improved, making it more cost-effective.

　#Three special readout modes: lightsheet mode and dual lightsheet mode

Flash 4.0 V3 has a lightsheet mode, which allows for adjusting the exposure time interval and direction between rows during camera Rolling Shutter readout, making it particularly suitable for improving the imaging quality of light sheets.

In addition, Flash 4.0 V3 also provides a dual lightsheet mode readout mode based on the lightsheet mode, allowing the readout directions on both sides of the camera chip to be adjusted separately, which is suitable for dual color film imaging.

　　W-View mode among three special readout modes

For the application of dual color imaging, Flash 4.0 V3 includes a very special W-View mode readout mode, allowing different exposure times to be set on both sides of a camera chip. Combined with the Hamamatsu W-View GEMINI dual color spectrometer, not only can dual color synchronous imaging be achieved, but also exposure times can be set separately when there is a large difference in dual channel signals, so that the intensity of the two channels' imaging tends to be consistent, which is convenient for observation and subsequent analysis.

The W-View GEMINI dual color splitter and W-View GEMINI-2C dual camera splitter, which can freely replace the filter, combined with special readout modes such as dual lightsheet mode and W-View mode in Flash 4.0 V3, provide Hamamatsu with extremely rich tools for dual color synchronous imaging, making it convenient for various needs.

　Enhanced Visualization Mode for Two Online Post Processing Options

Flash 4.0 V3 can select Enhanced Visualization mode for real-time data processing during image preview, which can make the sample structure more prominent and easier to observe and find when the signal strength is weak.

　Multi level hot pixel correction between two online post-processing options

In some applications, such as when imaging and analyzing moving objects, a small number of hot pixels may cause inaccurate data analysis; However, in other applications, any post-processing of images is not desirable. In order to meet such different needs, Flash 4.0 V3 allows for four levels of hot pixel calibration. In the strongest calibration, even long exposed images will not show hot pixels; On the other hand, one can also choose to obtain the most primitive data without any correction at all.

　Master Pulse: Camera built-in signal generator

The flexibility and user friendliness of external triggering settings have always been one of the focuses of the Flash 4.0 series. In Flash 4.0 V3, Hamamatsu has added a Mustar Pulse signal generator, allowing dual or even multiple cameras to achieve fully synchronized data acquisition at the hardware level.