HDR (High Dynamic Range)

HDR (High Dynamic Range) Function

Conventional microscope cameras capture 8-bit color images, displaying up to 256 levels of color gradation.
With KEYENCE's VHX Series Digital Microscope, images can be captured with 16-bit or 65,536 levels of color gradation.
This results in images with 256 times more color information than conventional 8-bit images and increases the number of representable colors by over 16 million times. All of this data is then processed by the VHX, which optimizes the color, brightness, contrast, and texture, and then displays the most suitable image given the object being observed.
Samples that were typically very difficult to observe using conventional microscope systems, such as low-contrast and reflective targets, can be easily imaged in high detail.

Processed with conventional engine [8-bit]
HDR [16-bit]
A
The color of the ink can be vividly depicted
B
Surface texture can be observed with better detail

Mechanisms Behind Obtaining 16-Bit HDR Data

In order to capture a 16-bit image, the camera will vary the shutter speed and take multiple images at different brightness levels. While there are 16-bits of information associated with each image, only 8-bits of data can be displayed at a given time. A user can specify which 8-bits of information to display, so that the appropriate feature or detail is clearly visible.

8-bit (256 levels of gray) conventional method

Gradations obtained using a single shutter speed

Difficulties
Narrow brightness range results in areas of an image with glare and dark spots (over and under saturated pixels).
Subtle contrast cannot be rendered.
Colors appear less vivid, and it is difficult to differentiate between similar shades.
16-bit (65536 levels) HDR function

Gradations obtained using multiple shutter speeds

Solutions
Wide range of brightness levels eliminate glare and under-exposed areas.
Minute surface features can be seen in sharp contrast.
True color appearance with subtle variations can be reproduced.

High performance graphics engine

The VHX Series contains KEYENCE's most advanced graphics engine, the REMAX V, capable of rendering RGB components with 16-bit gradation, even while viewing a live image.
This processor has been designed specifically to maximize the capabilities of the VHX functions - speed, resolution, real-color reproduction and operation.

Advantages of HDR [1]

Applications that were difficult to observe with conventional microscopes can now be effortlessly imaged.
The entire target can now be observed with consistent illumination throughout; from dark crevices to areas with overpowering glare.

Conventional
HDR [16-bit]
Connector (100×)

Structures that have almost no contrast can be observed in detail.
Easily render detailed structural images of targets with low contrast.

Conventional
HDR [16-bit]
Height difference gauge (2000×)

Advantages of HDR [2]

Even detailed images of transparent targets can be accurately captured.

Conventional
HDR [16-bit]
Glass fragment (50×)

Targets with subtle color differences can now be easily distinguished.

Conventional
HDR [16-bit]
Tablet (30×)

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