Analyze TOP

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Summary
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The Analyze TOP takes any image and determines various characteristics of it, such as the average pixel color, the pixel with the maximum luminance, or the min and max values in each channel. The result is stored in a 1x1, 1xN or Nx1 image depending on the chosen scope (See Scope parameter below). The calculated values can be brought into CHOPs using the TOP to CHOP node.

Note: When using the minimum and maximum operators, the default behaviour is to select the pixel with the highest value as chosen in the Analyze Channel parameter. For example, if Luminance is selected, the output will be the RGBA values of the pixel with the highest luminance, not the luminance value itself. Similarly, if a single channel is selected e.g. Red, Green, Blue, etc, then the output will be the pixel with the highest red value, rather than the highest values in each channel. To find the min or max values in each channel separately, set the Analyze Channel to RGBA Independent.

Note: When the operation is set to Count Pixels or Sum, the output image will default to a 32 bit floating point format in order to properly store the output data. For all other operations, the default output format will match the input format. The image format can be set manually using the parameter on the Common page.

Note: Using the Exclude NaNs or Mask features will slow down the performance of the node and should only be enabled if they are necessary.

PythonIcon.pnganalyzeTOP_Class


Parameters - Analyze Page

Operation op - - The operation to perform on the input image.

  • Average average - Find the average value in each channel of the input image. This operation is notably slower when the Exclude NaNs or Mask features are used as the node must perform two passes to calculate the results.
  • Minimum minimum - Find the pixel with the lowest value as determined by the 'Analyze Channel' parameter. See Notes in the summary for more details.
  • Maximum maximum - Find the pixel with the highest value as determined by the 'Analyze Channel' parameter. See Notes in the summary for more details.
  • Count Pixels count - Calculates the number of valid pixels in the input image. By default, the output will be fixed based on the dimensions of the image as determined by the 'Scope' parameter e.g. Full Image = width*height. When Exclude NaNs is enabled or a Mask is defined, the output will be the number of pixels that pass the mask and NaN checks. By default, when counting pixels the output image will be set to a 32bit floating point format.
  • Sum sum - Calculates the sum of all pixels in the input image by adding all of the values together. By default, the output image will be set to a 32bit floating point format in order to correctly store the output result.

Analyze Channel analyzechannel - - Determines what value the operation is being performed on. For example, when the operation is Minimum and the Analyze Channel is Red, the output will be the pixel with the lowest red value (not necessarily the lowest Blue or Green values). To separately find the lowest value in each channel, set this parameter to RGBA Independent.

  • Luminance luminance - The output results are based on the luminance of the input pixels. Luminance is the relative intensity of the pixel based on the values in the RGB channels. Note: the output contains the original RGBA values of the pixel with the highest/lowest luminance, not the luminance value itself.
  • Red red - Calculations are based only on the value in the red channel.
  • Green green - Calculations are based only on the value in the green channel.
  • Blue blue - Calculations are based only on the value in the blue channel.
  • Alpha alpha - Calculations are based only on the value in the alpha channel.
  • RGB Average rgbaverage - Calculations are based on the average value of the RGB channels.
  • RGBA Average average - Calculations are based on the average value of the RGBA channels.
  • RGBA Independent independent - Calculations are performed on each channels separately. Use this mode if you want to find the highest/lowest values in each channel.

Scope scope - - Determines how pixels are grouped together to calculate the results.

  • Full Image image - Calculations are performed on all pixels of the input image and combined into a single pixel result.
  • Rows rows - Calculations are performed on each row of the input separately, resulting in an output image that is one pixel wide and the same number of rows as the input.
  • Columns columns - Calculations are performed on each column of the input separately, resulting in an output image that is one pixel tall and the same number of columns as the input.

Exclude NaNs excludenans - Enable this parameter to skip pixels with a NaN value in the input image. NaNs typically represent errors in previous calculations (such as dividing by zero), but they can also be used to represent invalid pixels in a point cloud image. When most operations encounter a NaN pixel, the resulting output will always be a NaN, so you must enable this parameter to get valid results. If you do not expect NaN values in your input, it is recommended to leave this parameter turned off since it will reduce performance.  

Mask mask - - This parameter allows you to exclude certain pixels based on the values in one or more channels in the input. For example, if set to Alpha, only pixels that have a non-zero value in the alpha will be included. This can be useful, for example, if you need to find the average position of a point cloud image that is using an Active channel to indicate which pixels store valid point data.

  • None none - No mask channel. All pixels will be used in the output calculations.
  • Red red - Only pixels with a non-zero value in the red channel will be used.
  • Green green - Only pixels with a non-zero value in the green channel will be used.
  • Blue blue - Only pixels with a non-zero value in the blue channel will be used.
  • Alpha alpha - Only pixels with a non-zero value in the alpha channel will be used.
  • RGBA Independent independent - Each channel will act as its own mask, so that only pixels will non-zero values will be used in the output calculations.


Parameters - Common Page

Output Resolution outputresolution - - quickly change the resolution of the TOP's data.

  • Use Input useinput - Uses the input's resolution.
  • Eighth eighth - Multiply the input's resolution by that amount.
  • Quarter quarter - Multiply the input's resolution by that amount.
  • Half half - Multiply the input's resolution by that amount.
  • 2X 2x - Multiply the input's resolution by that amount.
  • 4X 4x - Multiply the input's resolution by that amount.
  • 8X 8x - Multiply the input's resolution by that amount.
  • Fit Resolution fit - Multiply the input's resolution by that amount.
  • Limit Resolution limit - Multiply the input's resolution by that amount.
  • Custom Resolution custom - Enables the Resolution parameter below, giving direct control over width and height.

Resolution resolution - - Enabled only when the Resolution parameter is set to Custom Resolution. Some Generators like Constant and Ramp do not use inputs and only use this field to determine their size. The drop down menu on the right provides some commonly used resolutions.

  • W resolutionw -
  • H resolutionh -

Resolution Menu resmenu - A drop-down menu with some commonly used resolutions.  

Use Global Res Multiplier resmult - Uses the Global Resolution Multiplier found in Edit>Preferences>TOPs. This multiplies all the TOPs resolutions by the set amount. This is handy when working on computers with different hardware specifications. If a project is designed on a desktop workstation with lots of graphics memory, a user on a laptop with only 64MB VRAM can set the Global Resolution Multiplier to a value of half or quarter so it runs at an acceptable speed. By checking this checkbox on, this TOP is affected by the global multiplier.  

Output Aspect outputaspect - - Sets the image aspect ratio allowing any textures to be viewed in any size. Watch for unexpected results when compositing TOPs with different aspect ratios. (You can define images with non-square pixels using xres, yres, aspectx, aspecty where xres/yres != aspectx/aspecty.)

  • Use Input useinput - Uses the input's aspect ratio.
  • Resolution resolution - Uses the aspect of the image's defined resolution (ie 512x256 would be 2:1), whereby each pixel is square.
  • Custom Aspect custom - Lets you explicitly define a custom aspect ratio in the Aspect parameter below.

Aspect aspect - - Use when Output Aspect parameter is set to Custom Aspect.

  • Aspect1 aspect1 -
  • Aspect2 aspect2 -

Aspect Menu armenu - A drop-down menu with some commonly used aspect ratios.  

Input Smoothness inputfiltertype - - This controls pixel filtering on the input image of the TOP.

  • Nearest Pixel nearest - Uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
  • Interpolate Pixels linear - Uses linear filtering between pixels. This is how you get TOP images in viewers to look good at various zoom levels, especially useful when using any Fill Viewer setting other than Native Resolution.
  • Mipmap Pixels mipmap - Uses mipmap filtering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail.

Fill Viewer fillmode - - Determine how the TOP image is displayed in the viewer. NOTE:To get an understanding of how TOPs work with images, you will want to set this to Native Resolution as you lay down TOPs when starting out. This will let you see what is actually happening without any automatic viewer resizing.

  • Use Input useinput - Uses the same Fill Viewer settings as it's input.
  • Fill fill - Stretches the image to fit the edges of the viewer.
  • Fit Horizontal width - Stretches image to fit viewer horizontally.
  • Fit Vertical height - Stretches image to fit viewer vertically.
  • Fit Best best - Stretches or squashes image so no part of image is cropped.
  • Fit Outside outside - Stretches or squashes image so image fills viewer while constraining it's proportions. This often leads to part of image getting cropped by viewer.
  • Native Resolution nativeres - Displays the native resolution of the image in the viewer.

Viewer Smoothness filtertype - - This controls pixel filtering in the viewers.

  • Nearest Pixel nearest - Uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
  • Interpolate Pixels linear - Uses linear filtering between pixels. Use this to get TOP images in viewers to look good at various zoom levels, especially useful when using any Fill Viewer setting other than Native Resolution.
  • Mipmap Pixels mipmap - Uses mipmap filtering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail.

Passes npasses - Duplicates the operation of the TOP the specified number of times. Making this larger than 1 is essentially the same as taking the output from each pass, and passing it into the first input of the node and repeating the process. Other inputs and parameters remain the same for each pass.  

Channel Mask chanmask - Allows you to choose which channels (R, G, B, or A) the TOP will operate on. All channels are selected by default.  

Pixel Format format - - Format used to store data for each channel in the image (ie. R, G, B, and A). Refer to Pixel Formats for more information.

  • Use Input useinput - Uses the input's pixel format.
  • 8-bit fixed (RGBA) rgba8fixed - Uses 8-bit integer values for each channel.
  • sRGB 8-bit fixed (RGBA) srgba8fixed - Uses 8-bit integer values for each channel and stores color in sRGB colorspace.
  • 16-bit float (RGBA) rgba16float - Uses 16-bits per color channel, 64-bits per pixel.
  • 32-bit float (RGBA) rgba32float - Uses 32-bits per color channel, 128-bits per pixels.
  • 10-bit RGB, 2-bit Alpha, fixed (RGBA) rgb10a2fixed - Uses 10-bits per color channel and 2-bits for alpha, 32-bits total per pixel.
  • 16-bit fixed (RGBA) rgba16fixed - Uses 16-bits per color channel, 64-bits total per pixel.
  • 11-bit float (RGB), Positive Values Only rgba11float - A RGB floating point format that has 11 bits for the Red and Green channels, and 10-bits for the Blue Channel, 32-bits total per pixel (therefore the same memory usage as 8-bit RGBA). The Alpha channel in this format will always be 1. Values can go above one, but can't be negative. ie. the range is [0, infinite).
  • 16-bit float (RGB) rgb16float -
  • 32-bit float (RGB) rgb32float -
  • 8-bit fixed (Mono) mono8fixed - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 8-bits per pixel.
  • 16-bit fixed (Mono) mono16fixed - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 16-bits per pixel.
  • 16-bit float (Mono) mono16float - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 16-bits per pixel.
  • 32-bit float (Mono) mono32float - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 32-bits per pixel.
  • 8-bit fixed (RG) rg8fixed - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 8-bits per channel, 16-bits total per pixel.
  • 16-bit fixed (RG) rg16fixed - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 16-bits per channel, 32-bits total per pixel.
  • 16-bit float (RG) rg16float - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 16-bits per channel, 32-bits total per pixel.
  • 32-bit float (RG) rg32float - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 32-bits per channel, 64-bits total per pixel.
  • 8-bit fixed (A) a8fixed - An Alpha only format that has 8-bits per channel, 8-bits per pixel.
  • 16-bit fixed (A) a16fixed - An Alpha only format that has 16-bits per channel, 16-bits per pixel.
  • 16-bit float (A) a16float - An Alpha only format that has 16-bits per channel, 16-bits per pixel.
  • 32-bit float (A) a32float - An Alpha only format that has 32-bits per channel, 32-bits per pixel.
  • 8-bit fixed (Mono+Alpha) monoalpha8fixed - A 2 channel format, one value for RGB and one value for Alpha. 8-bits per channel, 16-bits per pixel.
  • 16-bit fixed (Mono+Alpha) monoalpha16fixed - A 2 channel format, one value for RGB and one value for Alpha. 16-bits per channel, 32-bits per pixel.
  • 16-bit float (Mono+Alpha) monoalpha16float - A 2 channel format, one value for RGB and one value for Alpha. 16-bits per channel, 32-bits per pixel.
  • 32-bit float (Mono+Alpha) monoalpha32float - A 2 channel format, one value for RGB and one value for Alpha. 32-bits per channel, 64-bits per pixel.


Operator Inputs

  • Input 0 -

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[[Category:TOPs ]]

An Operator Family that creates, composites and modifies images, and reads/writes images and movies to/from files and the network. TOPs run on the graphics card's GPU.

A parameter in most CHOPs that restricts which channels of that CHOP will be affected. Normally all channels of a CHOP are affected by the operator.

A CHOP outputs one or more channels, where a channel is simply a sequence of numbers, representing motion, audio, etc. Channels are passed between CHOPs in TouchDesigner networks. See also Export.

The width and height of an image in pixels. Most TOPs, like the Movie File In TOP can set the image resolution. See Aspect Ratio for the width/height ratio of an image, taking into account non-square pixels.

The viewer of a node can be (1) the interior of a node (the Node Viewer), (2) a floating window (RMB->View... on node), or (3) a Pane that graphically shows the results of an operator.