Appearance & Measurement Experts since 1986


Rhopoint ID In-line Transparent Appearance Analysis

  • Camera-based system
  • Quantify product transparency with parameters that are highly correlated to human perception
  • Short or long focal distance versions available to suit customer production line
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Extended warranty

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Try before you buy

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Extended warranty

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Why measure the appearance of transparent materials with an inline solution?

The functionality of a manufactured product or its perceived quality is often linked to its transparency. Matt shipping labels require good contact clarity which allows QR codes to be read on high-speed conveyor lines, while recycled salad trays are preferred with low haze so the consumer can appreciate the vibrant colours of packed vegetables.

To optimise and improve transparency, a constant inline measurement of key parameters is more efficient than occasional offline measurements. Instant feedback from an sensors allows fine tuning of a process, ultimately achieving a better-quality product, with measured consistency throughout every production run.

Materials with high optical quality have low visual impact on objects viewed through them. The material itself is visually unobtrusive and almost invisible to the observer.

A hazy material causes colour seen through the material to appear washed out or faded. The severity of this loss of contrast is often related to the size of the gap between the object and the material.

A material which blurs the view of objects has low sharpness- this effect can be directional causing a visible pattern to be seen in the material.

Materials with poor optical qualities are visually intrusive and can be described as milky or opalescent. Patterns and texture which may be visible in the material drastically blur viewed objects.

The Rhopoint ID measurement technology (patent pending) was jointly developed with Eidgenössische Technische Hochschule (ETH) Zürich.

What is the Rhopoint ID-Inline?

The Rhopoint ID-Inline is a camera-based system which fully quantifies product transparency with parameters that are highly correlated to human perception.

Versions of the Rhopoint ID-Inline

There are two versions of the Rhopoint ID-Inline. A short focal length version which has a separation distance of 45mm between the camera and graticule, or the long focal distance version which has a separation distance of 170mm.

Rhopoint ID Inline short focal

Short focal distance

The Rhopoint ID-Inline can be used for non-contact measurement of any sheeted or planar material - including plastic films, or glass. The Rhopoint ID-Inline can also be used for non-contact inline measurement of glass or plastic tubes.

Rhopoint ID Inline long focal

Long focal distance

This version is most suitable for production processes where the large focal distance is more suited to the customer production line.

Rhopoint ID Inline product measurement station

Measurement Station

Either version can be incorporated into an inspection station for 3D parts or large sheets of plastic or glass.

Standard or extended clearance models are available to encompass a wide variety of parts and installation configurations.

What software integrations are available for the Rhopoint ID-Inline?

Flexible software allows single or multiple ID sensors to be combined with compatible measurement devices and tabulated in the Rhopoint ID laboratory software.

Using Rhopoint ID Software

Up to 5 ID units or compatible sensors can be connected to and controlled by the ID-L software. The instrument calculates batch statistics, detailed measurement images and displays trend graphs of all measurement parameters.

Using Rhopoint TCP/IP Client

Up to 10 Rhopoint ID-Inline units can be connected simultaneously to a SAP/process control package using the Rhopoint ID TCP/IP connection client. This solution allows independent remote control of each instrument, measurement data is exchanged using Rhopoint TCP/IP protocol.

The TCP/IP client is designed to facilitate fast efficient operation of multiple devices by the SAP/process control package. Up to 10 measurements per second are possible from each sensor. The client can be hosted on a local PC or server.

Measurement Parameters of the Rhopoint ID-Inline

Haze = 0%
Haze = 30%
Haze = 0%
Haze = 30%


Haze: quantifies the loss of contrast for objects viewed through a material.

When a material has haze, it changes the appearance of both the material and any objects viewed through it. This can lead to a reduction in perceived quality.

  • The product viewed through the material appears lifeless and dull – but details remain sharp
  • The colour of a viewed object appears washed-out and faded
  • The material itself appears cloudy or milky.

Measure Haze with the Rhopoint ID to ensure visibility of products are at their best and can be seen properly by the customer.

What affects Haze?

Haze can be affected by factors such as the choice of resin, the moulding process and any surface textures. Haze can be caused by:

Raw material choice

For example, a plastic with an incorrect melt viscosity for a particular process.

Process parameters

Cooling a plastic material too quickly can introduce micro textures onto the surface of the film or structures in the bulk which reduce optical quality.

Machine wear

Wear and tear in moulds, chill rollers and slip dies can induce visible surface defects in the material.

Measuring Haze with the Rhopoint ID


Sharpness quantifies the loss of perceived detail for objects viewed through a material.

What are the effects of reduced Sharpness?

When viewed through a material with high sharpness, an object appears sharp and distinct. As material sharpness decreases, the object appears blurry and obscured.

High Sharpness (S = 98.71%)
Medium-High Sharpness (S = 76.34%)
Medium-Low Sharpness (S = 49.62%)
Low Sharpness (S = 18.02%)

Anisotropic Sharpness. Only available with Rhopoint ID-L version.

A material can often exhibit optical effects which are directional. These phenomena are often induced in plastic parts by specific processing faults.

Visible texture is a common feature of plastic films and causes a significant reduction in their see- through quality.

Directional Effects

The Rhopoint ID is the only instrument that can measure directional effects in materials using the ID laboratory analysis software.

The images to the right show the visual impact of different ID Sharpness (S) values in vertical and horizontal directions.

Measuring directional effects can be used in advanced optical quality control and for adjusting processing parameters to obtain optimal transparency.

SV = 95%
SH = 70%
SV = 80%
SH = 95%

  • ID sharpness gives improved measurement resolution compared with clarity
  • ID Clarity is fully compatible with existing instruments

Note: Clarity and Sharpness do NOT capture poor optical characteristics associated with wavy/orange peel surfaces.


Quantifies the blurriness of an object when viewed through a material, results are proportionate with Sharpness, but the measurement scale is compressed and the measurement resolution is reduced.

Clarity is a scale used by traditional haze and clarity meters. When measured using the 8mm adaptor plate, Rhopoint ID Clarity data conforms to specifications written for these meters.

Inter-instrument Clarity agreement between Rhopoint ID and traditional sphere instruments for commercial plastic films (<1000μm) is typically <0.4% C (SD).

Inter-instrument Clarity agreement between traditional sphere instruments and Rhopoint ID for thick transparent plastic materials (<6mm) is typically <0.5% C (SD).

High clarity
Medium clarity
Low clarity
ID Sharpness measurement

Better measurement resolution than clarity.

ID Clarity

Compatible measurement with existing measurements.

Visible Transmittance

When considering how material is perceived by a consumer it is important to consider how bright an object viewed through it will appear.*

Visible Transmission to human observer

  • Rhopoint Transmittance (TID) quantifies the amount of light passing through the material and reaching the camera/eye of the observer
  • This measurement describes the brightness/ luminosity of the viewed object and is correlated to how one perceives the quality of the material.
Visible Transmittance
Visible Transmittance

*Traditional hazemeters measure total transmission which is related to light absorption not visual perception


Rhopoint ID Inline product inline

Rhopoint ID-Inline Sensor

Continuous measurement of in-line process including:

Rhopoint ID Inline product station

Rhopoint ID-Inline Inspection Station

Recommended for large object measurements including:

Sensor features

The Rhopoint ID has been designed to measure samples for haze, transmittance and sharpness quickly and safely.

No moving parts

Eliminates risk of mechanical failure

High sampling rate 10/s

Highly representative measurement throughout production run

Fully sealed light source

No chance of dust/dirt contamination

Rhopoint ID Inline Product Sensor
Single or multiple sensors

Flexible installation options allow multiple sensor installation

Easy Installation

Can be fitted by an in-house engineering team

Run as a laboratory system

Single or multiple Rhopoint ID-Inline sensors can be used with IDTX-L software with image analysis and project saving capabilities.

Connect to SAP/PLC

Connect to internal systems for full product control – ready for industry 4.0.


Connect to Rhopoint ID-Inline sensors from any PC on the same network – access live images using Rhopoint ID software.

Focal distance

  • Short focal distance – 45mm
  • Long focal distance – 170mm

Detailed analysis software

The Rhopoint ID-L analysis software enables detailed visual analysis of the sample using LIVE VIEW. Statistical analysis of multiple test results is shown for each measured parameter. • Saves all the results as a CSV file

  • Imports previous CSV results
  • Saves CSV results and all images as tiff
  • Imports CSV results and image tiff files


Repeatability SD0.
Reproducibility SD10.20.50.3
Inter-instrument Agreement Rhopoint ID vs
Traditional Haze & Clarity Instrument SD*
Effective Operating RangeMaterials
T > 50%
T > 50%
T > 50%

*Typical values- packaging film <1000µm

Instrument Information
Material Thickness< 30mm
Software ID Analysis or TCP/IP Client
ConnectionPOE LAN
Spatial Resolution9µm/pixel
Measurement Image12.5mm x 12.5mm
Minimum Measurement Area (Haze, Sharpness)12mm x 8mm
Minimum Measurement Area (Transmittance)12mm x 8mm
Image Format16-bit .TIFF
Image Size1400 x 1400 pixels
Operating Temperature10ºC - 40ºC
DimensionsShort focal distance - 270mm (H) x100mm (W) x100mm (D)
Long focal distance - 440mm (H) x 100mm (w) x 100mm (D)
Packed Weight5.0kg
Light Source Unit Power12V DC/2A
Camera Unit PowerPower Over Ethernet (POE)
ProductIncluded AccessoriesOrder Code
Rhopoint ID In-line Short Focal Distance (45mm)Haze check standard, USB stick with software and licence, power connector, value = 10%A3100-101
Rhopoint ID In-line Long Focal Distance (170mm)Haze check standard, USB stick with software and licence, power connector, value = 10%A3100-100
Individual Check Standards10% or 20%10% - B3100-005
20% - B3100-006
Calibration Standards Set1, 5, 10, 20, 35B3100-007
Transmission Check Standard70%B3100-008
Free extended warranty

Free extended 2 year warranty: Requires registration at within 28 days of purchase. Without registration, 1 year standard warranty applies.

Calibration and service

Fast and economic service via our global network of accredited calibration and service centres. Please visit for detailed information.

Answers to common questions about our instruments and measurements

Why measure gloss?

Gloss is an aspect of the visual perception of objects that is as important as colour when considering the psychological impact of products on a

Read More »

What is RSpec?

RSpec is the peak reflectance measured over a very narrow angular band in the specular direction (+/-) 0.0991º. RSpec is very sensitive to any texture

Read More »

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Rhopoint ID In-line Transparent Appearance Analysis