Pixel Info toolbox

Ocean 2020 introduces a new widget called “Pixel Info”. Its purpose is to regroup all image analysis tools present in Ocean, and provide you with a more consistant interface.

General overview

The pixel info widget lets you declare positions of interest (PoI) on an image, and measure properties of the image at these positions. Pixel Info allows you to declare two types of positions : points and areas. On the following image, we can see points (D, E, F, G) and areas (A, B, C) were defined for a render of the cornellbox. Note : some measures are only available to one or the other type of positions (see specific metrics for more details).

Pixel Info toolbox screenshot

Render of the cornellbox example with 7 positions of interest declared.

Positions of interest

Important actions :

  1. Declare positions of interest (PoI)

    Two buttons let you declare new positions of interest in an image

    Two buttons let you declare new positions of interest in an image

    You can declare new positions of interest in an image using the add-button and pick-button buttons, present both in the Pixel Info header or the Positions view of the Pixel Info widget (see image on the right). The first button lets you imput precisely the coordinates of a point or an area. The second button allows you to draw positions of interest directly on an image.

    Alternatively, you may also declare points of interest through the right click context menu of image previews (see image below).

    A shortcut to declare points of interest is present in the right click context menu of image previews

    A shortcut to declare points of interest is present in the right click context menu of image previews

  2. Display measures at a position of interest (PoI)

    You can select measures to display by selecting a position of interest. Once a position is selected, the Pixel Info widget will display all measures that could be computed for this position. Depending of 3 criterion, only a subset of measures may be available for a position of interest. These criterion are :
    • the information available in the image (RGB, XYZ, Spectral, ….).

    • the type of the position (point or area).

    • weither the rendering was ongoing or not when the position was declared.

    By default, the last added positions will be selected for analysis. To select a different position, you may (as shown in the image bellow) :
    • click on a position in the image, in the central view.

    • click on a position in the image preview, in the Image tool of the Pixel Info widget.

    • click on a position in the position list of the the Positions tool of the Pixel Info widget.

    Pixel Info toolbox screenshot

    Select a position of interest to display its measures

  3. Manage positions of interest

    Pixel Info toolbox screenshot

    You can also access these actions through the context menu

    Positions of interest (PoI) can be deleted (delete-button) and moved (move-button) or duplicated (duplicate-button) between images. All actions relative to PoIs are regrouped in the Positions tool of the Pixel Info widget. First, select the positions to modify, then click on an action button.

    Alternatively, you can also access these actions through the right click context menu of the Positions tool.

    Pixel Info toolbox screenshot

    Move and duplicate positions of interest between images.

  4. Hide and show positions of interest

    By default, positions of interest are represented in the central view. You can chose to hide them through the right click context menu of the central view (Show metrics positions). Alternatively, you may also chose to only hide specific PoIs. using the controls present in the Positions tool of the Pixel Info widget.

    Pixel Info toolbox screenshot

    Hide and show positions of interest in the central view.

Enable specific measures

You can chose to enable or disable measures. Ocean will only compute measures you have enabled, and your choices of measure remain between two executions of Ocean. The icon-settings button allows you to select measures (in the header of the Pixel Info widget). The context menu it opens lets you disable whole groups of measures (presets), or specific measures directly. Alternatively, you may also disable a measure by simply clicking on the close-button next to its name.

Enable or disable metrics

You may enable or disable measures. Only enabled measures are computed by Ocean.

List of tools

As of this version (Ocean 8.1.1), 5 categories of tools are availables in the Pixel Info widget :

  • Position Tools
    • image : shows a preview of the last image displayed.

    • Positions : shows the list of positions associated to the last image displayed, and allows the user to manage them.

  • Geometry Tools
    • Geometry Infos : shows diverse infos about the geometry at the selected position.

    • X-Ray Materials : shows all materials intersected by a ray sent at the selected position.

  • Colorimetry Tools
    • Gamut : shows the mean colors of all positions on the CIE color diagram.

    • Whitepoint : allows the user to declare a whitepoint reference for colorimetry analysis.

    • Colorimetry : shows colorimetry values of the selected position.

    • Colorimetry (compare) : shows colorimetry values of a second position, and the color difference between the selected position and the second positions.

  • Photometry Tools : shows photometry values of an image, at the selected position.

  • Spectrometry Tools : shows spectrometry values of an image, at the selected position.

Position Tools

The position tools allow the user to see and manage the positions analyzed.

Tools details :

  1. Image preview

    • The image preview shows the last image displayed, and all the positions associated to it.

  2. Position List

    • The position list displays all positions associated with the last displayed image in the central widget. In this list, the currently selected position (for analysis) is shown in highlight color.

    • Clicking on a position in the list will change the position selected for analysis. You can rename a position by double clicking on its name in the position list. Right clicks on the position displays a context menu with more options.

Geometry Tools

Pixel Info toolbox screenshot

Geometry tools

Limitations : point position and ongoing rendering required.

These tools retrieve geometry informations about the scene of an image. The geometry tools only work on point positions, during the rendering of a scene.

Tools details :

  1. Geometry infos

    • The Geometry Infos tool shoots a ray perpendicular to the image plane, from the selected position, and retrieves various geometric informations relative to every surface this ray passes through. The distance displayed is the distance between the camera and the intersected object.

  2. X-Ray Materials

    • The X-Ray Materials tool shoots a ray perpendicular to the image plane, from the selected position, and retrieves a list of every material associated with a surface this ray passes through.

Pixel Info toolbox - photometry tools screenshot

X-Ray materials

Colorimetry Tools

Pixel Info toolbox - colorimetry tools screenshot

Colorimetry tools

Limitations : X, Y and Z channels required.

These tools make color measurements on an image. The colors are analyzed before applying the output (post-processing). It requires that the buffer contains X, Y and Z channels, defined in the instrument channel spectra (also known as observers).

Color differences are calculated using the CIE76 standard. Lab values are relative to the whitepoint reference selected.

Important actions :

  1. Select a whitepoint reference

    • You can declare a new position to use as a whitepoint reference using the icon-pipet icon, in the top right corner of the Whitepoint tool. You can select a different position to use as a whitepoint reference by right clicking onto it in the positions list (Positions tool), and selecting “use as whitepoint reference”.

Pixel Info toolbox - photometry tools screenshot

Gamut tool for color analysis

  1. Select a second position for comparison

    • You can select two positions you want to compare by:
      1. selecting a first position for analysis;

      2. right clicking onto a position in the positions list (Positions tool), and selecting “compare (colorimetry)”.

Photometry Tools

Pixel Info toolbox - photometry tools screenshot

Photometry tools

Limitations : Y or energy channel required.

This tool makes luminous measurements on an image. Luminous values require a “Y” sensor channel or an energy sensor channel to be defined, and assume that it was spectrally integrated with a luminous function. This is the case if the sensor is of the standard CIE XYZ sensor type, which uses the photopic CIE 1931 standard luminous function.

The displayed physical quantities depend on the instrument type

The Unified Glare Rating (UGR) value is computed according to the CIE 117-1995 standard. In order to account for the full human field of vision, it should be used with a Fisheye camera, and the pipet region should enclose the full image. However, the algorithm is able to compute the glare rating restricted to a smaller field of vision.

Spectrometry Tools

Pixel Info toolbox - spectrometry tools screenshot

Spectrometry tools

Limitations : Spectral sensor required.

This tool makes spectrum measurements on an image. It requires a spectral image, simulated with an instrument having a spectral sensor. It displays a graph and the tabulated data of the spectrum. Tabulated data can be copied using the icon-copy button, or saved to a file using the icon-save button.