HDR (High Dynamic Range)

HDR (High Dynamic Range) Function

With KEYENCE's VHX Series Digital Microscope, images can be captured with 16-bit or 65,536 levels of colour gradation.
This results in images with 256 times more colour information than conventional 8-bit images and increases the number of representable colours by over 16 million times. All of this data is then processed by the VHX, which optimises the colour, brightness, contrast, and texture, and then displays the most suitable image given the object being observed.
Samples such as low-contrast and reflective targets can be easily imaged in high detail.

Without HDR [8-bit]
With HDR [16-bit]
The colour of the ink can be vividly depicted
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 grey) Without HDR

Gradations obtained using a single shutter speed

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

Gradations obtained using multiple shutter speeds

Wide range of brightness levels eliminate glare and under-exposed areas.
Minute surface features can be seen in sharp contrast.
True colour 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 maximise the capabilities of the VHX functions - speed, resolution, real-colour reproduction and operation.

Advantages of HDR [1]

The entire target can now be observed with consistent illumination throughout; from dark crevices to areas with overpowering glare.

Without HDR [8-bit]
With 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.

Without HDR [8-bit]
With HDR [16-bit]
Height difference gauge (2000×)

Advantages of HDR [2]

Even detailed images of transparent targets can be accurately captured.

Without HDR [8-bit]
With HDR [16-bit]
Glass fragment (50×)

Targets with subtle colour differences can now be easily distinguished.

Without HDR [8-bit]
With HDR [16-bit]
Tablet (30×)