Probabilistic image analysis
A method for detecting at least one object of interest in at least one raw data x-ray image includes the steps of emitting an incident x-ray radiation beam through a scanning volume having an object therein, detecting x-ray signals transmitted through at least one of the scanning volume and the object, deriving the at least one raw data x-ray image from the detected x-ray signals, inputting the raw data x-ray image, expressed according to an attenuation scale, into a neural network, for each pixel in the raw data x-ray image, outputting from the neural network a probability value assigned to that pixel, and, classifying each pixel in the raw data x-ray image into a first classification if the probability value associated with the pixel exceeds a predetermined threshold probability value and in a second classification if the probability value associated with the pixel is below the predetermined threshold probability value.
1. A method for detecting at least one object of interest in at least one raw data x-ray image, the method comprising the steps of:
emitting an incident x-ray radiation beam through a scanning volume having an object therein;
detecting x-ray signals transmitted through at least one of the scanning volume and the object;
deriving the at least one raw data x-ray image from the detected x-ray signals;
inputting the raw data x-ray image, expressed according to an attenuation scale, into a neural network;
for each pixel in the raw data x-ray image, outputting from the neural network a probability value assigned to that pixel, wherein the probability value is indicative of whether the pixel is likely associated, or not likely associated, with a potential threat; and,
classifying each pixel in the raw data x-ray image into at least one of a first classification or second classification based on whether the probability value associated with the pixel exceeds, or does not exceed, a predetermined threshold probability value.
2. The method of claim 1 , wherein the step of inputting the raw data x-ray image expressed according to an attenuation scale further comprises the steps of:
determining a transmittance value for each pixel in the raw data x-ray image; and,
determining an attenuation value from each transmittance value.
3. The method of claim 1 , wherein the outputting step outputs a probability map for each pixel in the raw data x-ray image.
4. The method of claim 3 , wherein the method further comprises: providing a colour-mapped image based on the probability map showing pixels classified in the first classification in a first colour scheme and pixels classified in the second classification in a second colour scheme.
5. The method of claim 4 , wherein the first colour scheme and the second colour scheme at least one of flashes, shifts hue and shifts luma.
6. The method of claim 1 , wherein the classifying step is by way of semantic segmentation.
7. The method of claim 1 , wherein the neural network is a convolutional neural network.
8. The method of claim 7 , wherein the convolutional neural network is a FC-Densenet.
9. The method of claim 1 , wherein the at least one raw data x-ray image includes a set of raw data dual-energy x-ray images.
10. A system for detecting at least one object of interest in at least one raw data x-ray image, comprising:
an x-ray emitter for emitting an incident x-ray radiation beam through a scanning volume having an object therein;
at least one detector for detecting x-ray signals transmitted through at least one of the scanning volume and the object;
at least one processor for deriving at least one raw data x-ray image from the detected x-ray signal;
at least one processor configured to:
input the raw data x-ray image, expressed according to an attenuation scale, into a neural network;
output from the neural network a probability value assigned to each pixel in the raw data x-ray image, wherein the probability value is indicative of whether the pixel is likely associated, or not likely associated, with a potential threat; and,
classify each pixel in the raw data x-ray image into at least one of a first classification or second classification based on whether the probability value associated with the pixel exceeds, or does not exceed, a predetermined threshold probability value.
11. The system of claim 10 , wherein to express the raw data x-ray image according to an attenuation scale, the at least one processor is further configured to:
determine a transmittance value for each pixel in the raw data x-ray image; and,
determine an attenuation value from each transmittance value.
12. The system of claim 10 , wherein to output the probability value assigned to each pixel in the raw data x-ray image, the at least one processor is further configured to output a probability map for each pixel in the raw data x-ray image.
13. The system of claim 12 wherein the at least one processor is further configured to provide a colour-mapped image showing pixels in the first classification in a first colour scheme and pixels in the second classification in a second colour scheme.
14. The system of claim 13 , wherein the first colour scheme and the second colour scheme at least one of flashes, shifts hue and shifts luma.
15. The system of claim 10 , wherein the neural network is configured to classify each pixel in the raw data x-ray image by way of semantic segmentation.
16. The system of claim 10 , wherein the neural network is a convolutional neural network.
17. The system of claim 16 , wherein the convolutional neural network is a FC-Densenet.