Patent Publication Number: US-2023161570-A1

Title: Learning user interface controls via incremental data synthesis

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 16/859,488, filed Nov. 29, 2020 and entitled “LEARNING USER INTERFACE CONTROLS VIA INCREMENTAL DATA SYNTHESIS,” which is hereby incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to the field of data processing systems and more particularly to detection of objects in images. 
     BACKGROUND 
     Detecting User Interface (UI) control objects using screen images or videos of a computer application is a key requirement for automating tasks. This is particularly the case with applications which reside behind firewalls and in virtual or remote desktop environments. In particular, as the demand for automation increases, it is imperative to recognize controls in legacy application programs which do not provide programmatic access, in order to automate usage of such applications. For websites, the code is available in one form or another so detection of controls and their type on the website is relatively straightforward. However, many licensed applications do not allow permit access to their code. Moreover, in certain situations, applications may be used by an automation user by way of remote desktop type software where only the screen image is available to the user. Automated detection of controls on such applications for automation is a challenge. 
     Building models to learn and detect such UI control objects from application screen images effectively requires a large number of images for training and testing of the models. However, obtaining sufficiently large number of such images in realistic business application scenarios is hard as businesses that use these applications are usually averse to sharing such images due to potentially sensitive information that these applications might contain about the business and its customers. 
     SUMMARY 
     Computerized methods and systems to detect user interface application controls are disclosed herein. In one embodiment, a computer-implemented method detects one or more user interface control objects contained in a screen image of a user interface generated by an application program. An initial dataset that comprises a plurality of images is accessed, where each of the images represents a screen of information containing one or more user interface control objects, where each user interface control object is part of a corresponding user interface control object class. A machine learning model is trained with a portion of the initial dataset, which is designated as a training portion of the initial dataset, to cause the machine learning model to detect user interface control objects in each of the plurality of object classes. The initial dataset is then modified by accessing screen images generated by at least a first application program and processing the screen images generated by the first application program to detect user interface control objects in the screen images generated by the first application program. A set of new application screen images is created as a function of the user interface control objects detected in the screen images generated by the first application program. An updated dataset is generated by modifying the initial dataset with the set of new application screen images. The machine learning model is further trained with the updated dataset to generate a retrained machine learning model. 
     Modification of the initial dataset may be performed by a data point generator which is employed to generate an updated synthesized image set. The data point generator may employ images generated by an application program as a reference by which to generate the updated synthesized image set. The images generated by the application program may be tagged in advance. Alternatively, or in addition, the images generated by the application program may be captured dynamically by a user using the application program, where in one embodiment, sensitive information is removed from the application program. 
     These and additional aspects related to the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the description or may be learned by practice of the invention. Aspects of the invention may be realized and attained by means of the elements and combinations of various elements and aspects particularly pointed out in the following detailed description and the appended claims. 
     It is to be understood that both the foregoing and the following descriptions are exemplary and explanatory only and are not intended to limit the claimed invention or application thereof in any manner whatsoever. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification exemplify the embodiments of the present invention and, together with the description, serve to explain and illustrate principles of the inventive techniques disclosed herein. Specifically: 
         FIG.  1    is a high-level block diagram illustrating an embodiment of a UI interface object detection system. 
         FIG.  2 A  is a screenshot showing an example of an original application screen image. 
         FIG.  2 B  is a screenshot showing a synthesized image based on the original application screen image of  FIG.  2 A . 
         FIGS.  3 ,  4 ,  5 ,  6 ,  7 ,  8 ,  9  and  10    are screenshots of examples of additional synthesized images with various object and image level invariances. 
         FIG.  11    is a flow diagram illustrating user action driven synthesis. 
         FIG.  12    is a flow diagram illustrating offline or passive synthesis. 
         FIG.  13    is a screenshot showing an example output of the trained model of  FIG.  1   ., at a step k. 
         FIG.  14    is a screenshot showing an example output of the trained model of  FIG.  1   ., at a step k+1. 
         FIGS.  15  and  16    are screenshots showing examples of synthesized images based on the application screen image shown in  FIG.  2 A . 
         FIGS.  17 ,  18 ,  19  and  20    are screenshots showing additional examples of original application screen images. 
         FIGS.  21 ,  22 ,  23 ,  24 ,  25 ,  26 ,  27  and  29    are screenshots showing examples synthesized images based on the application screen images shown in  FIGS.  17 ,  18 ,  19  and  20   , respectively. 
         FIGS.  30 ,  31 ,  32  and  33    are screenshots showing a first example of synthesized images. 
         FIGS.  34 ,  35 ,  36  and  37    are screenshots of showing a second example of synthesized images. 
         FIG.  38    illustrates a block diagram of hardware that may be employed in an implementation of the RPA systems disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference will be made to the accompanying drawings, in which identical functional elements are designated with like numerals. Elements designated with reference numbers ending in a suffix such as . 1 , . 2 , . 3  are referred to collectively by employing the main reference number without the suffix. For example,  100  refers to topics  100 . 1 ,  100 . 2 ,  100 . 3  generally and collectively. The aforementioned accompanying drawings show by way of illustration, and not by way of limitation, specific embodiments and implementations consistent with principles of the present invention. The screenshots shown in certain of the drawings are greyscale conversions from screenshots originally generated in color. These implementations are described in sufficient detail to enable those skilled in the art to practice the invention and it is to be understood that other implementations may be utilized and that structural changes and/or substitutions of various elements may be made without departing from the scope and spirit of present invention. The following detailed description is, therefore, not to be construed in a limited sense. 
     Any computer application consists of User Interface (UI) control objects that the user interacts with to complete one or more tasks. These controls take for example, mouse clicks or keyboard inputs or combinations thereof from the user to perform one or more actions intended to complete the intended task. Therefore, any system that understands and automates such tasks, such as a Robotic Process Automation (RPA) system, utilizes understanding of such UI controls. Further, understanding and automating processes, which comprise a sequence of tasks, may involve one or more tasks from one or more applications. Therefore, a system and method that detects UI controls across several applications is desirable. Such systems and methods that are robust and fast allow for accurate task and process automation that is very significant from a business value perspective. 
     The task of UI control detection becomes even more challenging when the corresponding applications reside in virtual and remote desktop environments and/or behind firewalls. In such cases, the user&#39;s computer has no direct access to the application but only an image or video screenshots that the user can interact with using a keyboard and mouse. In such scenarios, any method to detect UI controls use the image or video as input. Usage of systems employing such virtual and remote desktop environments continues to be highly desirable given increasingly high standard safety and privacy requirements and regulations. Further, information technology departments prefer installing applications that require high complexity computing environment in virtualized computers so that they don&#39;t have to teach or support each of their employees individually for installing and maintaining these applications on their computers. 
     Even though an application may look the same and interact in the same way across different computing environments, the internal functionalities of how it implements those interactions may vary quite a bit across computers, depending on what underlying application framework, operating system and hardware those particular computers have. For example, a web page may look almost same to the user and would work the same way whether a user views it in Firefox® browser, Internet Explorer® browser or Chrome® browser, but the internal workings of these browsers and how they interact with operating system are very different from each other. Similarly, a Java®-based Oracle application would look the same on two computers, such as one with Windows® OS and the other with Mac® OS but their underlying JVMs (Java Virtual Machines) are very different. Further, the speed of the application will be governed by the underlying hardware of those computers. A UI control detection method that is agnostic to application framework and computing environments is therefore desirable. An image or video-based method is accordingly desirable in this case and in particular one that uses only the visual aspects of the UI and not the internal working of the UI. Such a technique would thereby be inherently agnostic to application frameworks and computing environments. 
     UI control object detection is used in the understanding and automation of business tasks and processes which often involve sensitive information about the business itself and their clients. For example, consider a bank that wants to automate the task of validating information in a user&#39;s loan application. Such loan applications contain information such as social security numbers of the applicants, their addresses, employers and other personal information. The divulsion of such information may lead to severe misuse or identity theft. Consequently, the bank prefers not to share such an information with any vendor and ideally would prefer humans to not see such information at all. On the other hand, machine learning systems to build accurate and robust UI control object detection models need datasets that represent real world distribution of such UI control objects in such realistic applications. 
     Application User Interfaces (UIs) are usually built from a finite set of visual effects, a layout and a style library. So even though realistic applications create their unique footprints and noise there are underlying structures that are shared across the applications. At an object level it means that application UIs follow similar invariance characteristics. As explained in further detail below, an invariance characteristic for an object is a characteristic across which the object might vary (or take different values) yet the object definition does not change. Disclosed herein are embodiments that define and capture the set of such image level and object level invariances across real applications and use them to synthesize datasets that mimic the distributions of these real applications. Certain disclosed embodiments are (i) self-supervised, meaning they do not require extensive human labeling of data, and (ii) privacy aware meaning they respect the privacy constraints imposed by the owner of the applications (e.g. no sharing of sensitive information). 
     A high-level description of the system  10  shown in  FIG.  1    is first provided followed by an explanation of various aspects of operation of the system  10 .  FIG.  1    shows an embodiment of a UI interface object detection system  10  where a set of synthesized images (D k )  102  is employed to train a machine learning (ML) engine  104 . The ML engine  104  may employ any one of a number of model architectures  106 . The ML engine  104  employs the synthesized images  102  to generate an initial trained model (M k )  108 . A data point generator  110  is employed to generate an updated synthesized image set  112  which is used to update at  114 , the initial dataset D k  of synthesized images  102  to an updated dataset D k +n  116  which may be used to further train the ML engine  104 . As explained in further detail herein, the data point generator  110  operates to generate additional data points, such as screen images, from actual screen images by employing the initial trained model  108 . 
     In certain embodiments, the system  10  implements a computer-implemented method for detecting one or more UI control objects contained in a screen image of a UI generated by an application program. An initial dataset is accessed, where the initial dataset has a plurality of synthetically generated images. Each of the synthetically generated images represents a screen of information containing one or more UI control objects, where each UI control object is part of a corresponding UI control object class. A machine learning model is trained with a portion of the initial dataset, that is designated as a training portion of the initial dataset, to cause the machine learning model to detect UI control objects in each of the plurality of object classes. In certain embodiments, the initial dataset is modified by accessing screen images generated by at least a first application program. In such embodiments, the screen images generated by the first application program are processed to detect UI control objects in the screen images generated by the first application program and a set of new application screen images is created as a function of the UI control objects detected in the screen images generated by the first application program. An updated dataset is generated by modifying the initial dataset with the set of new application screen images. The machine learning model is further trained with the updated dataset to generate a retrained machine learning model. 
     The operation of accessing screen images generated by the first application program may be performed by retrieving a set of tagged screen images where each screen image of the set of tagged screen images has for one or more UI control objects in the screen image, a set of tagged bounding boxes, with each tagged bounding box surrounding a corresponding UI control object, and a tagged object class identifier that classifies the corresponding UI control object into one of a plurality of object classes. The tagging in the embodiments disclosed includes associating one or more identifiers to a UI control object, such as to a bounding box associated with a UI control object and providing an object class identifier that identifies an object class for the UI control object of interest. 
     The operation of processing the screen images generated by the first application program to detect UI control objects in the screen images generated by the first application program may be performed by processing the set of tagged screen images with the machine learning model, as trained by the initial dataset, to generate for each tagged screen image of the set of tagged screen images, a set of detected bounding boxes, where each of the bounding boxes has associated therewith an object class label that identifies an object class associated with a UI control object within the associated bounding box. A confidence score is also generated for each bounding box where the confidence score is indicative of a level of confidence of identification of the UI control object within the associated bounding box. For each tagged screen image the set of detected bounding boxes is compared to the set of tagged bounding boxes to generate a set of failure cases comprising missed or incorrectly identified bounding boxes. Invariance parameters associated with each UI control object contained in the set of failure cases are collected. A set of updated invariance parameters is generated by updating invariance parameters employed by the machine learning engine as a function of the invariance parameters associated with each UI control object contained in the set of failure cases. 
     The operation of creating a set of new application screen images as a function of the UI control objects detected in the screen images generated by the first application program may also include generating for each new application screen image of the set of new application screen images, one or more UI control objects as a function of the updated invariance parameters. 
     The operation of accessing screen images generated by at least a first application program may also include capturing application screen images generated by the first application program as the first application program is used by a user of the first application program. The operation of processing the screen images generated by the first application program to detect UI control objects in the screen images generated by the first application program may also include processing each captured application screen image with the machine learning model, as trained by the dataset, to generate for each captured application screen image, a set of detected bounding boxes where each of the bounding boxes has associated therewith an object class label that identifies an object class associated with a UI control object within the associated bounding box and a confidence score indicative of a level of confidence of identification of the UI control object within the associated bounding box. The UI control objects within the detected bounding boxes may then be presented to the user to permit interaction by the user, with the user inputs being captured. 
     An example of a privacy constraint noted above would be that no textual information entered in a UI control object, such as a “TEXTBOX” and that selected in a “COMBOBOX” are to be shared or used, but all other info can be shared and used. In such a scenario, disclosed embodiments automatically create a version of the application UI keeping all image level info but erase or replace information inside the “TEXTBOX” and “COMBOBOX”. Another example of a privacy constraint would be to replace all text information except those in UI control objects of “BUTTON” class. This is shown in  FIGS.  2 A and  2 B .  FIG.  2 A  shows a screenshot of an original application screen which includes a variety of UI control objects such as text boxes, seen generally at  202 , labels, seen generally at  203 , buttons, seen generally at  205  and tabs, seen generally at  208 .  FIG.  2 B  shows a screenshot of a synthesized image to mimic that of  FIG.  2 A  while respecting privacy constraints which in this instance is to remove or replace all text information except buttons. In the example shown in  FIG.  2 B , the text in the text fields  202  has been removed by replacing the content of the field with background color of the field and the text for the labels is randomly generated. 
     The self-supervised nature of certain embodiments calls for an initial dataset that has not encountered any real-world data yet. The datasets may be characterized using the distributions of the datapoints inside them along with a set of invariance parameters. An invariance parameter for an object is a parameter across which the object might vary (or take different values) yet the object definition does not change. For example, one invariance of a UI control object “TEXTBOX” is width as no matter what the width is “TEXTBOX” is still a “TEXTBOX”. Another way to look at an invariance parameter is from the machine learning system or method itself. It is desirable to have a learning system trained to detect such an object and to be invariant to any value the parameter takes. For example, the same detection model should be able to detect all textboxes of all widths. The invariances can include both object level invariances such as height, width, aspect ratio, colors, texts inside controls etc., and image level invariances such as how the controls are arranged in the application, and the resolution, noise etc. Therefore, in one embodiment, based on the properties of the objects a set of object level invariance parameters is created. The initial dataset D k  is synthesized based on these initial set of invariance parameters in a manner in which their values are distributed uniformly in reasonable intervals. For example, for the UI control object “TEXTBOX”, the object properties may comprise a rectangular shape with borders and may be filled with certain color and text inside its rectangular region. These properties are captured by invariance parameters width, height, border width and color, type of color inside the box, color, font, size of the text inside the box etc. By values taken uniformly from reasonable intervals, we mean that the values for each of these parameters is picked a random with equal probability from a list of values. For example, width may take a value in an interval of 20 pixels to 1000 pixels as “TEXTBOX” is expected to be laid out on a UI application presented in full HD resolution along with other textboxes. Similarly, a color for inside of the rectangular region of the TEXTBOX may come from a set of 500 colors picked after dividing a color wheel in 500 parts. Border width may range from 1 pixel to 5 pixels etc. Further, this initial dataset D k  is also given image level invariance by putting various kinds of layouts of the objects inside the image and their relative geometric positions. This is shown in  FIGS.  3 - 10    which provide examples of synthesized images with such object and image level invariances. As seen in  FIGS.  3 - 10    a variety of UI control objects are generated for each screen image, such as textboxes  202  and associated labels  203 , dropdowns  302  and checkboxes  304 . For textboxes  202 , which call for information to be entered by a user, some textboxes have random text entered while others are left empty. A variety of background colors  306  are generated (seen converted to greyscale). Some of the UI control objects are set in a regular or ordered pattern, such as in  FIGS.  4 ,  6 ,  9 ,  10    while others appear to have a random pattern, such as seen in  FIG.  5   . While the ordering may appear to be random, the varied ordering facilitates learning by a machine learning engine. Additionally, the UI control objects are of varying dimensions with varying aspect ratios. Additionally, certain screen images, such as seen in  FIG.  8    may show multiple UI windows  802  each with their own UI control objects. Further, certain screen images, such as seen in  FIG.  10    may have a UI window which consumes only a portion of the screen image. 
     UI controls are characterized by a finite set of types of controls, such as for example, text boxes, drop-down selection boxes, buttons, tabs, etc. Such controls though can have a wide degree of variation in how they are arranged. Also, noise can occur in captured images, such as when a screen image is displayed on a low-resolution screen. Page layouts can also vary and can be affected by user preferences on display choices (font sizes, colors, etc.). Moreover, the sequence of images provided to a user by an application can vary based on user inputs (for example, a user selection of an option on the screen will often result in a change in the screen image and UI controls displayed). Given that the object properties for the various UI controls are known in advance, invariance parameters for each of the different type of UI controls can be employed to create the initial dataset of images as shown by way of example in  FIGS.  3 - 10   . Generation of the initial dataset may be accomplished by way of a software program that generates known layouts along with use of randomness in the selection of UI controls, their invariance parameters and layouts, to achieve translational invariance with a goal to generate an initial dataset of sufficient size to train a machine learning model. By way of example, the initial dataset may be around fifty thousand images, with forty thousand allocated for training and ten thousand allocated for validation. The initial dataset may not have any actual example of an actual application screen, as generated by any given application program, to be detected but will contain the UI control objects sought to be detected, even though actual arrangement of any given image in initial dataset may not match any actual screen to be detected. 
     Turning back to  FIG.  1   , once initial dataset D k  is synthesized it is incrementally augmented and updated (to generate D k+n ) using model training. This is followed by one or more data point generation techniques  110  that employ the trained model  108  to guide the synthesis of new data either actively using user actions performed during an interaction session with an application, shown at  120  and/or using a passive inference process on unseen examples of application UI screenshots, shown at  122 . 
     Training model  108  involves training a model to detect a set of given objects (UI controls for instance) with a dataset  116  where the model  108  is invariant to a set of invariance parameters. A model architecture is selected at  106 . In one embodiment, the model architecture consists of a convolutional Deep Neural Network (DNN) comprising a shared network, a classification network and a box regression network that processes the image region wise and outputs a set of detected boxes, the corresponding class label and the corresponding confidence scores. The model may take a number of forms. With a model that takes the form of a DNN, the model can be a variety of types including Faster-RCNN, R-FCN, SSD, RetinaNet etc. Given a model architecture, the model training involves continuously improving the parameters of the model using the dataset  116  until the parameters converge to an optimum value (local or global) as measured by a loss or cost function. One example of such a loss function is the weighted sum of the offsets of the detected bounding boxes for the objects compared to ground truth values, and the cross entropy between correct and detected object classes for those boxes. The offsets of the bounding boxes determine how well the model is learning to localize the objects correctly. Cross entropy measures how well the model is learning to classify the correct class of the object captured by the detected bounding box. At the end of this stage, a model M k  is produced which works as an object detector meaning it takes an image as an input and outputs a set of object bounding boxes (as coordinate values in the image), the corresponding object classes, and corresponding confidence scores. 
     In one embodiment, object detection and invariance parameter identification may be performed by breaking a UI object into certain constituent object parts, or component sub-objects, also referred to as sub-control objects, so that the constituent object parts have a limited variability range with respect to the invariance parameter and are amenable to be learned effectively by a machine learning model. For example, a textbox object which may have an object class “TEXTBOX” and an invariance parameter ‘aspect ratio’, may be broken down into two parts—(1) “LEFT_TEXTBOX” sub-object created using the left most part of the textbox object with the original height, and the width equal to the original height (2) “RIGHT_TEXTBOX” sub-object created using the right most part of the textbox object with the original height, and the width equal to the original height. Once a model learns to detect these sub-object parts, these sub-objects (i.e. “LEFT_TEXTBOX” and “RIGHT_TEXTBOX”) are combined to construct the object “TEXTBOX”. The trained model M k  is used by the data point generator  110  which identifies new instances of invariances and generates data to improve the model M k . This may be performed by using (i) an unseen set of application UI screenshot examples  124  and/or (ii) a new user interaction session, by a user  126  via a device  128  of an application  130 , employing a bot recorder  132  to synthesize new datapoints (i.e. images), to capture the new object and image level invariance scenarios present in the unseen set and/or the new user interaction session. Further details are shown in  FIGS.  11  and  12   . The new set of images synthesized at this stage  112  are then included at  114  into the current dataset D k  and the process of learning (i.e. training new models) and incrementally synthesizing and augmenting dataset repeats.  FIGS.  13  and  14    illustrate how the quality of the model trained in this way improves.  FIG.  13    shows the detections output of the object detection model at step k and  FIG.  14    shows the detections output of the object detection model at step k+1. As seen in  FIG.  13   , a variety of UI control objects have been detected. As seen in  FIG.  14   , a variety of UI control objects have been detected. Note that the textboxes with search icons or calendar icons that were missing in step k ( FIG.  13   ) are now detected correctly (in step k+1 ( FIG.  14   ). 
     The operations to perform the user action driven synthesis  120  are shown in  FIG.  11   . An application UI, of application  130  is initiated at  1102  and one or more screenshots of this application UI is captured as images at  1104  by bot recorder  132  as user  126  uses the application  130 . Each captured image is then at  1106  passed through the object detection model M k  which outputs a set of bounding boxes, the corresponding object class labels and the corresponding confidence scores. This object detection model M k  detects text on the captured image as well. Additionally, another model to perform automatic text detection may be used. This operation at  1106  generates a set of UI control objects and a set of text in the captured image all in the form of bounding boxes, object class labels and confidence scores. Further, a mapping between these UI control objects and texts may also be established. The detected UI control objects are then presented to the user at  1108  as part of the application  130  that the user  126  is interacting with. In one embodiment the presentation of detected UI control objects to the user  126  is performed by highlighting the detected UI control objects contained in an application screen presented to the user  126 . The user  126  then performs the actions that he/she intends to do e.g. text entry, selecting from a combobox, selecting a checkbox or a radio button or clicking on a text or image button. The system  10  captures all of these actions, irrespective of whether a UI control object with which the user  126  interacts has been detected, by way of bot recorder  132 . Depending upon the quality of the object detection model at this kth iteration of the synthesis, some of the detected UI control objects and texts may be wrong. Depending upon the action performed by the user on a UI control object, its class label is validated at  1110 . For example, even though a TEXTBOX is wrongly detected as say a BUTTON, if the user  126  does a keyboard entry during interaction, the system identifies that the correct class is TEXTBOX and the model had made an error. In one embodiment, user  126  can further explicitly draw a bounding box for a control that is missing or incorrect and associate a right object class label to it. Therefore, either a detected UI control object is corroborated or corrected by the user action performed on that UI control object. These validated set of UI control objects are now used at  1112  to extract object level characteristics of the image. For each object, the value of associated invariance parameters are calculated—parameters such as background color of the object, border styles, present or absence of text, dimensions, shapes, actual pixel values of the interesting part of the objects etc. In addition to the object level characteristics or invariances, the originally captured application UI is further used to compute at  1114  image level characteristics or invariances such as overall background color, layout styles, geometric arrangement or alignment of the UI control objects etc. These two sets of invariance parameter values are then used at  1116  to synthesize one or more images. At this point, a set of privacy constraints  1115  may be applied as well. The privacy constraints  1115  dictate what information must be erased or replaced in the original image. In one embodiment, a synthesized image is created with monochromatic background color which is the dominant color computed from the original image, and all the UI control objects are drawn at their exact locations in the original image with uniform colors inside them with value equal to their corresponding dominant colors in the original image, thereby erasing any textual input they might have inside them. The text values are all replaced by a set of random strings and are placed at the locations where text was present in the original image. As seen, such an embodiment operates to use the style of a UI control without the associated content. Additional images are synthesized by choosing a subset of the UI control objects and a subset of the original text locations and placing them on an image with uniform background or one of the various calculated layouts from the original image. A subset of the textboxes and comboboxes may further be entered with a random string each. For the original application UI depicted in  FIG.  2 A ,  FIGS.  15  and  16    provide additional examples of synthesized images. In  FIG.  15    each of the UI control objects has been retained, with the exception of the tabs at  208 , the text has been removed with random text being added as labels and the text fields being empty.  FIG.  16    is similar with the labels  203  being different than in  FIG.  15    with random text being added to the text fields  202 . Similarly,  FIGS.  21 - 29    are some examples of synthesized images for the original application screen images shown in  FIGS.  17 - 20    respectively. The synthesized images include various combinations of textboxes  202 , labels  203 , buttons  205 , dropdowns  302 , checkboxes  304 , background colors  306  (shown in greyscale) and windows  802 . As can be appreciated, a single application UI image can result in many images, in some cases at a 10:1 or higher ratio. 
     The offline or passive synthesis  122  is now described with respect to  FIG.  12    to synthesize images to mimic given application UIs. At a kth iteration of the incremental learning, L I,k  is the known list of invariance parameters and V I,k  is the set of values associated with invariance parameters. In the beginning operation  1202 , these parameters and values (L I,k  and V I,k ) are computed simply based on object properties as described previously in context of the initial dataset creation. Given a new set of application UI Images which may additionally come tagged with correct object bounding boxes and their object classes, the model M k  is applied on the images. For each image, the model outputs a set of detected bounding boxes, corresponding object class labels and the confidence scores. The tagging may be performed manually by users of an application program. Alternatively, the tagging may be performed semi-automatically. For example, a second image might be just a simple modified version of a first image where certain action on controls has been performed (e.g. text entry in a TEXTBOX, click on a CHECKBOX). In this case the UI control object class and location for each control in the second image is the same as that in the first image and can be tagged as such automatically. 
     For each object instance in each of the images, the model may detect a correct bounding box as per an overlap measure, a correct or incorrect class for the bounding box, or it may completely miss that object instance. The misses as well as incorrect predictions are designated at  1204  as failure cases. For each case where an expected object is either detected incorrectly or is missing, every invariance parameter associated with that object class is collected along with the correct values for the invariance parameters on the object instances in the object class. This failure characterization operation results in update of invariance parameters and values at  1206  that were unseen before, V I,k +1 and L I,k +1 respectively. For example, for UI control object class “TEXTBOX”, if the model fails on application UIs with very wide textboxes, the values for invariance parameters “aspect_ratio” and “width” gets updated. In another example, where a new kind of textbox is seen with a search icon on the right side, a new invariance parameter called “icon style” will be added to the set of invariance parameters of object class “TEXTBOX” with a value equal to “search icon”. The updated values are then used to synthesize new images at  1208  wherein the objects with the properties satisfying the new invariance parameter and values appear. In the first example, shown at  FIGS.  30 - 33   , the synthesized images will include wide textboxes along with other size textboxes. The screen images shown in  FIGS.  31 ,  32  and  33    are synthesized from the screen image shown in  FIG.  30    along the invariance parameter “width” with larger values i.e. very wide boxes. As can be seen, there is a wide variety in the synthesized images in  FIGS.  31 ,  31  and  33    between each other and from the original image of  FIG.  30   . The number, type, background color (shown in greyscale) and aspect ratios of the UI control objects vary widely among the synthesized images and from the original. The synthesized images include various combinations of textboxes  202 , labels  203 , buttons  205 , dropdowns  302 , checkboxes  304 , background colors  306  (shown in greyscale) and windows  802 . The disclosed embodiments operate to capture wide textboxes in a variety of contexts both at the UI control object and image level. 
     In the second example, shown at  FIGS.  34 - 37   , synthesized images will include textboxes with search icons inside them. The screen images in  FIGS.  35 ,  36  and  37    are synthesized from the screen image in  FIG.  34    along the invariance parameter “icon style” with a new value of “search icon”. As can be seen, there is a wide variety in the synthesized images in  FIGS.  35 ,  36  and  37    between each other and from the original image of  FIG.  34   . The “New Task” overlay of  FIG.  34    results in the synthesized image of a single, smaller window in a larger screen shown in  FIG.  35   , multiple, smaller windows in a larger screen in  FIG.  36   , and the wide horizontal UI portion of a larger window in  FIG.  37   . The key idea is to capture the “search icon” in variety of contexts both at object and image level. 
     The system  10  exhibits a number of advantages in accurately recognizing application controls. One, it is self-supervised meaning that it does not require extensive human labeling of data. Second, it is privacy aware meaning it respects the privacy constraints imposed by the owner of the applications (e.g. no sharing of sensitive information). Third, it allows creation of a large and varied dataset as is required to train a model for UI control detection that is robust and accurate on real application screens. Fourth, it is agnostic to applications, application frameworks, and computing environments. 
     Although the embodiments described herein are set forth in the context of UI control object detection, the disclosed embodiments may also be employed in other machine learning environments where the solution and data collection is constrained by privacy requirements and constraints. Moreover, other embodiments, may recognize objects in document images other than those generated by software application programs. Such document images typically would have well-defined objects inside the documents. This is true for any number of business documents such as invoices, claim forms, and other such documents. Such documents contain objects such as address blocks, tables, signatures, and other structured information blocks and associated invariance parameters based on the properties of those objects. In embodiments that process such document images, the offline or passive synthesis  122  operates as described herein. The user action driven synthesis  120  in such an embodiment may operate by notifying and requesting interaction by a user  126  when the model fails (e.g. when a model would be expected to detect an object type in the document but fails to detect it). In such an instance, the user  126  corrects or completes the object detection where the model failed. This interaction is captured and data point generator  110  generates additional document images for further training of the object detection model as described herein. 
     The detected controls may be employed in a robotic process automation system. In such a system, a software robot (also referred to as a bot) comprises a plurality of sets of task processing instructions. Each set of task processing instructions is operable to interact at a user level with one or more designated user level application programs (not shown). A bot that employs the detected controls can operate to detect application controls in an application in an environment where only the application screen image is available to the bot. With the detected application controls, the bot can perform the task processing instructions to interact with the application(s) specified in the task processing instructions. 
     The embodiments herein can be implemented in the general context of computer-executable instructions, such as those included in program modules, being executed in a computing system on a target real or virtual processor. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The program modules may be obtained from another computer system, such as via the Internet, by downloading the program modules from the other computer system for execution on one or more different computer systems. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Computer-executable instructions for program modules may be executed within a local or distributed computing system. The computer-executable instructions, which may include data, instructions, and configuration parameters, may be provided via an article of manufacture including a computer readable medium, which provides content that represents instructions that can be executed. A computer readable medium may also include a storage or database from which content can be downloaded. A computer readable medium may also include a device or product having content stored thereon at a time of sale or delivery. Thus, delivering a device with stored content, or offering content for download over a communication medium may be understood as providing an article of manufacture with such content described herein. 
       FIG.  38    illustrates a block diagram of hardware that may be employed in an implementation of the RPA system as disclosed herein.  FIG.  38    depicts a generalized example of a suitable general-purpose computing system  3800  in which the described innovations may be implemented in order to improve the processing speed and efficiency with which the computing system  3800  operates to perform the functions disclosed herein. With reference to  FIG.  38    the computing system  3800  includes one or more processing units  3802 ,  3804  and memory  3806 ,  3808 . The processing units  3802 ,  3806  execute computer-executable instructions. A processing unit can be a general-purpose central processing unit (CPU), processor in an application-specific integrated circuit (ASIC) or any other type of processor. The tangible memory  3806 ,  3808  may be volatile memory (e.g., registers, cache, RAM), non-volatile memory (e.g., ROM, EEPROM, flash memory, etc.), or some combination of the two, accessible by the processing unit(s). The hardware components in  FIG.  38    may be standard hardware components, or alternatively, some embodiments may employ specialized hardware components to further increase the operating efficiency and speed with which the system  10  operates. The various components of computing system  3800  may be rearranged in various embodiments, and some embodiments may not require nor include all of the above components, while other embodiments may include additional components, such as specialized processors and additional memory. 
     Computing system  3800  may have additional features such as for example, storage  3810 , one or more input devices  3814 , one or more output devices  3812 , and one or more communication connections  3816 . An interconnection mechanism (not shown) such as a bus, controller, or network interconnects the components of the computing system  3800 . Typically, operating system software (not shown) provides an operating system for other software executing in the computing system  3800 , and coordinates activities of the components of the computing system  3800 . 
     The tangible storage  3810  may be removable or non-removable, and includes magnetic disks, magnetic tapes or cassettes, CD-ROMs, DVDs, or any other medium which can be used to store information in a non-transitory way, and which can be accessed within the computing system  3800 . The storage  3810  stores instructions for the software implementing one or more innovations described herein. 
     The input device(s)  3814  may be a touch input device such as a keyboard, mouse, pen, or trackball, a voice input device, a scanning device, or another device that provides input to the computing system  3800 . For video encoding, the input device(s)  3814  may be a camera, video card, TV tuner card, or similar device that accepts video input in analog or digital form, or a CD-ROM or CD-RW that reads video samples into the computing system  3800 . The output device(s)  3812  may be a display, printer, speaker, CD-writer, or another device that provides output from the computing system  3800 . 
     The communication connection(s)  3816  enable communication over a communication medium to another computing entity. The communication medium conveys information such as computer-executable instructions, audio or video input or output, or other data in a modulated data signal. A modulated data signal is a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media can use an electrical, optical, RF, or other carrier. 
     The terms “system” and “computing device” are used interchangeably herein. Unless the context clearly indicates otherwise, neither term implies any limitation on a type of computing system or computing device. In general, a computing system or computing device can be local or distributed and can include any combination of special-purpose hardware and/or general-purpose hardware with software implementing the functionality described herein. 
     While the invention has been described in connection with the disclosed embodiments, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.