Patent Document ID: 7675655
Application ID: 10547652
Patent Status: 1

Claim One:
1. An apparatus for scanning a moving object, the apparatus having a sensor oriented to collect a series of images of the object as it passes through a sensor field of view and image processing means arranged to input the series of images and to form a composite image therefrom, the image processing means including: a) motion estimating means for generating an estimate of object image motion between images in the series of images, including image analysing means for deriving, for pixels within a current image from the series of images, likelihood measures indicating likelihoods of respective pixels corresponding to parts of the object; and b) display processing means for generating a composite image to which the series of images contributes at positions derived from estimated object image motion; wherein i) the series of images includes a predecessor image obtained prior to the current image, and the motion estimating means is arranged to generate an estimate of object image motion between the current image and the predecessor image from image pixels weighted in accordance with the likelihood measure, and ii) the likelihood measure is derived from intensity of the current image pixel, intensity of a second pixel located in the predecessor image equivalently to the current image pixel, and intensity of a third pixel which is in the predecessor image and is estimated to be imaging an object region which is the same as that imaged by the current image pixel, the third pixel having a location derived by compensation for object motion, and estimates of standard deviations of noise in the object image intensity and background image intensity σ b in accordance with equations as follows: likelihood ⁢ ⁢ measure = w f ⁡ ( x , y ) = p f ⁡ ( x , y , Δ ⁢ ⁢ x i ) p f ⁡ ( x , y , Δ ⁢ ⁢ x i ) + p b ⁡ ( x , y ) , ⁢ where ⁢ : p f ⁡ ( x , y , Δ ⁢ ⁢ x i ) = 1 2 ⁢ ⁢ π σ b ⁢ exp ⁡ ( - ( I p t ⁡ ( x , y ) - I p t - 1 ⁡ ( x + Δ ⁢ ⁢ x i , y ) ) 2 2 ⁢ ⁢ σ f 2 ) , ⁢ and p b ⁡ ( x , y ) = 1 2 ⁢ ⁢ π σ b ⁢ exp ⁢ ⁢ ( - ( I p t ⁡ ( x , y ) - I p t - 1 ⁡ ( x , y ) ) 2 2 ⁢ ⁢ σ b 2 ) .