1. A method for contour-based determination of malignant tissue in a thermal image of a patient for cancer screening, the method comprising: receiving a thermal image of a patient for cancer screening, wherein the thermal image is captured by a thermal imaging camera, the thermal imaging camera comprising: an array of sensors that converts infrared energy into electrical signals on a per-pixel basis; a lens that focuses the infrared energy from the patient's breast onto the array of sensors, wherein the array of sensors detects temperature values from the patient's breast; and a specialized processor that processes the detected temperature values into at least one block of pixels to generate the thermal image, wherein pixels in the thermal image with a higher temperature value being displayed in a first color and pixels with a lower temperature value being displayed in a second color, pixels with temperature values between the lower and higher temperature values being displayed in gradations of color between the first and second colors; analyzing the thermal image to identify a patch of pixels with an elevated temperature relative to a temperature of pixels associated with surrounding tissue; determining a boundary contour of the identified patch of pixels; calculating a measure of irregularity of the boundary contour, wherein the measure of irregularity is calculated by selecting a plurality of points along a best-fit ellipse around the pixel patch; calculating a distance between the points along the boundary contour and the points along a best-fit ellipse; and determining, in response to the distance being at or above a threshold, that a shape of the boundary contour of the pixel patch is determined to be irregular, and regular otherwise; determining, based on the measure of irregularity, that tissue associated with the pixel patch is malignant and non-malignant otherwise; and displaying the irregular boundary contour that represents the malignant tissue and the regular boundary contour that represents the non-malignant tissue in different colors.