A system comprising: a predefined reference pattern comprising a plurality of optically-perceptible elements (62, 64, 66), the optically-perceptible elements comprising at least a first and a second pair of optically perceptible elements (62, 64, 66, 72, 74, 76), wherein each optically perceptible element of the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76) has a same first predefined dimension (a, c, e, g, i, k), wherein each optically perceptible element of the second pair of optically perceptible elements (62, 64, 66, 72, 74, 76) has a same second predefined dimension (a, c, e, g, i, k) different from the first predefined dimension, wherein the optically-perceptible elements of the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76) are separated from each other by a first predefined distance (b, d, f, h, j, 1), wherein the optically perceptible elements of the second pair of optically perceptible elements (62, 64, 66, 72, 74, 76) are separated from each other by a second predefined distance (b, d, f, h, j, l); and a dimensioner (20, 24, 36) configured to: determine at least one dimension of an object (16, 40); measure the first predefined dimension (a, c, e, g, i, k) of each optically perceptible element of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76) from one or more images of the predefined reference pattern captured by the dimensioner; measure the first predefined distance (b, d, f, h, j, 1) between the optically perceptible elements of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76); and calculate a ratio between the measured first predefined dimension (a, c, e, g, i, k) of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76) of the plurality of optically-perceptible elements (62, 64, 66, 72, 74, 76) and the measured first predefined distance (b, d, f, h, j, 1) between the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76), wherein the dimensioner is further configured to be calibrated based on the calculated ratio and on dimensions of distances between two optically perceptible elements having different dimensions. a predefined reference pattern comprising a plurality of optically-perceptible elements (62, 64, 66), the optically-perceptible elements comprising at least a first and a second pair of optically perceptible elements (62, 64, 66, 72, 74, 76), wherein each optically perceptible element of the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76) has a same first predefined dimension (a, c, e, g, i, k), wherein each optically perceptible element of the second pair of optically perceptible elements (62, 64, 66, 72, 74, 76) has a same second predefined dimension (a, c, e, g, i, k) different from the first predefined dimension, wherein the optically-perceptible elements of the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76) are separated from each other by a first predefined distance (b, d, f, h, j, 1), wherein the optically perceptible elements of the second pair of optically perceptible elements (62, 64, 66, 72, 74, 76) are separated from each other by a second predefined distance (b, d, f, h, j, l); and a dimensioner (20, 24, 36) configured to: determine at least one dimension of an object (16, 40); measure the first predefined dimension (a, c, e, g, i, k) of each optically perceptible element of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76) from one or more images of the predefined reference pattern captured by the dimensioner; measure the first predefined distance (b, d, f, h, j, 1) between the optically perceptible elements of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76); and calculate a ratio between the measured first predefined dimension (a, c, e, g, i, k) of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76) of the plurality of optically-perceptible elements (62, 64, 66, 72, 74, 76) and the measured first predefined distance (b, d, f, h, j, 1) between the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76), wherein the dimensioner is further configured to be calibrated based on the calculated ratio and on dimensions of distances between two optically perceptible elements having different dimensions. determine at least one dimension of an object (16, 40); measure the first predefined dimension (a, c, e, g, i, k) of each optically perceptible element of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76) from one or more images of the predefined reference pattern captured by the dimensioner; measure the first predefined distance (b, d, f, h, j, 1) between the optically perceptible elements of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76); and calculate a ratio between the measured first predefined dimension (a, c, e, g, i, k) of the first pair of optically-perceptible elements (62, 64, 66, 72, 74, 76) of the plurality of optically-perceptible elements (62, 64, 66, 72, 74, 76) and the measured first predefined distance (b, d, f, h, j, 1) between the first pair of optically perceptible elements (62, 64, 66, 72, 74, 76), wherein the dimensioner is further configured to be calibrated based on the calculated ratio and on dimensions of distances between two optically perceptible elements having different dimensions.