Blob Grayscale Analysis

Blob Grayscale Analysis

Calulates histograms of blobs in a gray scale image. The blobs are marked with labels given in the labeled image input. Calculates also statistical features from the histograms.

Inputs

image
Input image.
labels
A labeled image which is typically created from the input image with BlobDetectionTool. Each connected blob in the output image is marked with a distinct numeric label. Pixels that belong to the first detected blob are ones, the pixels that belong to the second one with twos and so on. Background is zero.

Outputs

histogram
A M-by-N matrix of histograms. M is the number of blobs and N is the maximum number of gray levels in the input image. M depends on the dynamic scale of the input image, but is always at least 256. Each contains a histogram calculated from those pixels in the input image which coincide with the corresponding label in the label image.
first
The index of the first non-zero value in the histogram. -1 if all values are zeros, otherwise the value is on range 0...N-1. A M-by-1 matrix.
last
The index of the last non-zero value in the histogram. -1 if all values are zeros, otherwise the value is on range 0...N-1. A M-by-1 matrix.
range
last - first + 1, or zero if the histogram is all zeros. A M-by-1 matrix.
sum
Sum of all entries in the histogram. A M-by-1 matrix.
mean
Mean of the dataset from which the histogram was calculated. A M-by-1 matrix.
weightedSum
Sum of all entries in the histogram weighted by the index of each entry. Computed as sum * mean. A M-by-1 matrix.
minIndex
The index of the minimum value. If there are many indices with the same value, this is the first one. A M-by-1 matrix.
maxIndex
The index of the maximum value. If there are many indices with the same value, this is the first one. A M-by-1 matrix.
variance
Variance of the dataset from which the histogram was calculated. A M-by-1 matrix.
stdDev
Standard deviation of the dataset from which the histogram was calculated. Computed as square root of variance. A M-by-1 matrix.
stdMean
Mean deviation of the dataset from which the histogram was calculated. Computed as average of absolute differences to the mean value. A M-by-1 matrix.
median
Median of the dataset from which the histogram was calculated. A M-by-1 matrix.
skewness
Skewness of the dataset from which the histogram was calculated. A M-by-1 matrix.
kurtosis
Kurtosis of the dataset from which the histogram was calculated. A M-by-1 matrix.