Author: Stefan Olsson
Published on IPQ website: 18 February 2014
Generally, embodiments of a technical solution described herein relates to a thermography arrangement or an IR imaging system, such as a thermal camera or an infrared (IR) camera, for capturing IR images and retrieving information from the IR images.
More specifically, different embodiments of the technical solution relate to enhancing captured IR images by optimizing parameters of the IR camera based on an observed scene.
IR cameras are typically used to capture and present IR images of an observed scene, or in other words visual representations of incoming IR radiation emitted from the observed scene. The incoming radiation may comprise temperature information related to the observed scene.
Over the last few years, an increasing number of IR cameras also comprise a visual light imaging subsystem for generating digital images in the visible light range. Such cameras often also comprise functions for fusing or blending the visible light images and the IR images in various ways. Typically, the visible light imaging subsystem has a fixed focus, or an autofocus function according to prior art methods.
Typically, a user of a prior art IR camera is looking at a display showing a visual representation (IR image) of an observed scene and imaged by the IR camera. In order to solve a specific task, the user is enabled to manually adjust parameters in a user interface, thereby adjusting the visual representation. The task may for example be to find a person or an object under difficult viewing conditions, such as in a desert, in a blizzard, in a cluttered environment or from a far distance, e.g. several kilometers. It is therefore very important that the parameters of the IR camera are correctly set in order to obtain the best possible image to solve the specific task. The operator must either know which parameters to change, and how to change them, or will have to perform random adjustments in a trial and error approach.
Therefore, a problem often arising for users of IR cameras is to adjust parameters controlling for example the noise filter, non-uniformity correction (NUC), range, integration time, digital detail enhancement (DDE), whether to use histogram or linear adjustment, autofocus settings, and so on. Such adjustments are today made manually by determining a characteristic of the observed scene in order to optimize an image appearance.
Also, in regard of technical advances being made in image processing functionality, users are left with a growing range of new parameters to adjust. The technical solution described herein addresses the problem for IR users in order to simplify the adjustments of parameters to obtain and optimized or enhanced image appearance.
For a user of an IR camera to know what parameters to adjust, based on the observed scene, in order to obtain an optimal image appearance is non-intuitive and time consuming to learn. The problem solved by the technical solution described herein comprises method embodiments for determining characteristics of the observed scene and a following input representing the determined characteristics.
DESCRIPTION OF THE TECHNICAL SOLUTION
The technical solution described herein comprises a method for enhancing, or optimizing, an IR image with the aim of finding an object or an area of interest in the IR image according to a specific task, using a high sensitivity IR imaging system. The method comprises the following steps:
i)Capturing an IR image of an observed scene using an IR camera.
According to one embodiment of the technical solution, the IR imaging system comprises both an IR camera and a VL camera for capturing IR images, and therefore the captured IR images comprise a selection of: IR pixels, VL pixels and/or mixed IR/VL pixels.
ii)Receiving a first input signal, wherein the first input signal comprises determined characteristics of the observed scene.
According to one embodiment of the technical solution, a selection of scene options for determining the characteristics of the observed scene are presented to the user, via a user input device, before or after capturing the IR image, wherein the scene options, i.e. parameters, describe a variation of possible observed scenes. The scene options best suited are activated based on an indication from a user of the IR camera, according to the user’s perception of the observed scene, resulting in the first input signal. The user input device is a display with touchscreen functions or buttons placed on the IR camera for receiving an indication from a user.
According to another embodiment of the technical solution, the IR camera comprises an automatic mode where external sensors coupled to the IR camera read and receive signals describing the characteristics of the observed scene. The read and received signals automatically activate the best suited scene option, based on predetermined settings.
According to another embodiment of the technical solution, different techniques for activating the best suited scene option in automatic mode comprise orientation based on angular momentum, range determination, acceleration between objects, humidity, temperature, and other forms of physical quantities known for one skilled in the art.
iii)Receiving a second input signal, via a user input device, wherein the second input signal comprises information on a task to be performed.
According to one embodiment of the technical solution, information on the task to be performed comprises further detailed information describing the observed scene with target options, additional to the scene options mentioned earlier. The target options are presented to the user and activated based on an indication from the user. The user builds a task mode this way that is optimized for a specific observed scene.
iv)Selecting an IR image processing setting, from a list of predefined IR image processing settings, based on the first input signal and the second input signal
According to one embodiment of the technical solution, selecting the IR image processing setting comprises a process of simultaneously displaying two IR images to the user, wherein a first IR image represents the captured IR image before any activated options for enhancing or optimizing the image appearance. A second IR image represents the IR image after activated scene options and target options for enhancing and optimizing image appearance. At this stage, the user is able to further improve the task mode optimized for a specific observed scene by comparing the two images, and either continue with the activated scene options and target options or erase these and restart the method.
v)Processing the IR image according to the selected IR image processing settings, thereby obtaining an IR image that is enhanced with regard to finding the object or area of interest in the IR image according to the indicated task.
According to one embodiment of the technical solution, the selected IR image and the built task mode is stored in the IR camera for future use. This way the user can time efficiently enable a previous selection and task mode for an observed scene similar to a previous observed scene.