Patent Publication Number: US-2023134984-A1

Title: Methods and apparatus to convert image to audio

Description:
RELATED APPLICATION 
     This patent claims the benefit of U.S. Provisional Patent Application No. 63/417,224, which was filed on Oct. 18, 2022. U.S. Provisional Patent Application No. 63/417,224 is hereby incorporated herein by reference in its entirety. Priority to U.S. Provisional Patent Application No. 63/417,224 is hereby claimed. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to neural networks and, more particularly, to methods and apparatus to convert image to audio. 
     BACKGROUND 
     In machine learning, a convolutional neural network is a type of feed-forward artificial network which captures spatial and temporal dependencies in images through the application of filters. Convolutional neural networks (CNNs) are widely used throughout computer vision to allow computer systems to derive a high-level understanding of images. Common CNN tasks include image classification and detection of text in an image 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an illustration of example environments in which transducer circuitry operates to convert an image to audio. 
         FIG.  2 A  is an illustration of a conversion of text to audio with the transducer circuitry of  FIG.  1   . 
         FIG.  2 B  is an illustration of conversion of text to audio with the image-to-audio neural network of  FIG.  1   . 
         FIG.  3    is a block diagram of an example implementation of the transducer circuitry of  FIG.  1    to convert text to audio. 
         FIG.  4    is an illustration of an example end-to-end image-to-audio system including the transducer circuitry of  FIG.  1    and the training circuitry  104  of  FIG.  1   . 
         FIG.  5    is a flowchart representative of example machine readable instructions and/or example operations that may be executed by example processor circuitry to implement the transducer circuitry of  FIG.  3   . 
         FIG.  6    is a flowchart representative of example machine readable instructions and/or example operations that may be executed by example processor circuitry to implement the training circuitry of  FIG.  1   . 
         FIG.  7    is a block diagram of an example processing platform including processor circuitry structured to execute the example machine readable instructions and/or the example operations of  FIGS.  5  and  6    to implement the transducer circuitry of  FIG.  2   . 
         FIG.  8    is a block diagram of an example implementation of the processor circuitry of  FIG.  7   . 
         FIG.  9    is a block diagram of another example implementation of the processor circuitry of  FIG.  7   . 
         FIG.  10    is a block diagram of an example software distribution platform (e.g., one or more servers) to distribute software (e.g., software corresponding to the example machine readable instructions of  FIG.  7   ) to client devices associated with end users and/or consumers (e.g., for license, sale, and/or use), retailers (e.g., for sale, re-sale, license, and/or sub-license), and/or original equipment manufacturers (OEMs) (e.g., for inclusion in products to be distributed to, for example, retailers and/or to other end users such as direct buy customers). 
       In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. The figures are not to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. Although the figures show layers and regions with clean lines and boundaries, some or all of these lines and/or boundaries may be idealized. In reality, the boundaries and/or lines may be unobservable, blended, and/or irregular. 
       As used herein, connection references do not necessarily infer that two elements are directly connected and/or in fixed relation to each other. As used herein, stating that any part is in “contact” with another part is defined to mean that there is no intermediate part between the two parts. 
     
    
    
     DETAILED DESCRIPTION 
     Artificial intelligence (AI), including machine learning (ML), deep learning (DL), and/or other artificial machine-driven logic, enables machines (e.g., computers, logic circuits, etc.) to use a model to process input data to generate an output based on patterns and/or associations previously learned by the model via a training process. For instance, the model may be trained with data to recognize patterns and/or associations and follow such patterns and/or associations when processing input data such that other input(s) result in output(s) consistent with the recognized patterns and/or associations. 
     In general, implementing a ML/AI system involves two phases, a learning/training phase and an inference phase. In the learning/training phase, a training algorithm is used to train a model to operate in accordance with patterns and/or associations based on, for example, training data. In general, the model includes internal parameters that guide how input data is transformed into output data, such as through a series of nodes and connections within the model to transform input data into output data. Additionally, hyperparameters are used as part of the training process to control how the learning is performed (e.g., a learning rate, a number of layers to be used in the machine learning model, etc.). Hyperparameters are defined to be training parameters that are determined prior to initiating the training process. 
     Different types of training may be performed based on the type of ML/AI model and/or the expected output. For example, supervised training uses inputs and corresponding expected (e.g., labeled) outputs to select parameters (e.g., by iterating over combinations of select parameters) for the ML/AI model that reduce model error. As used herein, labelling refers to an expected output of the machine learning model (e.g., a classification, an expected output value, etc.) Alternatively, unsupervised training (e.g., used in deep learning, a subset of machine learning, etc.) involves inferring patterns from inputs to select parameters for the ML/AI model (e.g., without the benefit of expected (e.g., labeled) outputs). 
     An image-to-text (ITT) model is a ML model that takes an image as input and recognizes text in the image. Generally, an ITT contains three modules: a rectifier, an image encoder, and a sequential decoder. The rectifier segments and normalizes images through transformation of the text into a normalized form. The image encoder extracts hidden representations from the normalized image, and the decoder generates a sequence of characters based on the hidden representations. 
     A text-to-speech (TTS) model takes text input and synthesizes the input into natural, human-intelligible speech. To do this, the TTS model first converts text, as a sequence of phonemes (e.g., any one of the perceptually distinct units of sound in a given language), to acoustic features. The acoustic features may be a sequence of mel-spectra in a mel-spectrogram. A mel-spectrogram is a spectrogram in which the frequencies that make up the sound in the spectrogram are converted to the mel scale (e.g., a scale in which equal distances in pitch sound equally distant to the listener). The TTS model then transforms the acoustic features into audio samples (e.g., through a vocoder). 
     Conventional solutions for converting image to speech (ITS) naively combine ITT models and TTS models to generate an ITS model. In other words, conventional solutions convert pixels to text using a first ML model, and then convert text to speech using a second ML model. However, naively combining ITT models with TTS models has multiple drawbacks. Such systems are large and computationally expensive to train, as the pipeline has many steps. Additionally, some portions of such systems are not neural network-based, so programmers must manually program these portions, increasing development costs. Problems arising at the interface between the ITT and the TTS models are especially common, such as when a conventional ITT model has a different output sequence length than the TTS model. 
     Technical solutions described herein present a system to transform text in an image to audio with a single ML model. By generating a single ITS model, the aforementioned drawbacks of multi-model systems can be avoided. Examples disclosed herein require less manual programming and operate more efficiently than conventional ITS solutions by presenting a complete, end-to-end, ITS model. 
     Disclosed examples may be especially useful when executing ITS tasks on neural network co-processors. A neural network accelerator is a processor that is optimized specifically to handle neural network workloads. Examples disclosed herein can be simply and efficiently implemented on neural network accelerators. Therefore, examples disclosed herein are efficient, with a reduced cost per watt and lesser power consumption when compared to prior solutions. 
     Disclosed examples include features such as padding intermediate outputs to generate a consistent length intermediate output. Disclosed examples additionally include duration predicator circuitry that can predict phoneme duration and associate a placeholder with a desired (e.g., zero) duration. 
     Disclosed examples present a non-autoregressive end-to-end image-to-audio neural network architecture that simplifies hardware design and the ITS inference process, while at the same time reducing memory requirements. Disclosed examples therefore present a non-autoregressive end-to-end neural network suitable for embedded hardware implementation of an image-to-audio subsystem in personal computing devices. Some examples may be used in an end-to-end image-to-audio neural network that generates audible representations of sub-screen snapshots near a finger or touch pointer. 
     Turning to the figures,  FIG.  1    is a schematic illustration of an example environment  100  in which transducer circuitry  102  operates to convert text to audio. The example environment  100  includes the example transducer circuitry  102 , example image-to-audio neural network circuitry  103 , example training circuitry  104 , example first training data  114   a , example second training data  114   b , an example server  106 , an example mobile device  108 , an example vehicle  110 , an example hospital  112 , and an example network  116 . 
     Users of computing devices such as cell phones, tablets, connected appliances, internet-of-things, and laptops may encounter situations where safety considerations or visual impairment make it difficult to take in display content. The environment  100  illustrates scenarios in which users of computing devices encounter such challenges. The transducer circuitry  102  (e.g., and any other elements of the image-to-audio neural network circuitry  103 ) can improve distracted and/or visually impaired (e.g., low vision) user&#39;s interaction with computing devices in such scenarios. 
     For example, a user may be unable to safely view a screen of the mobile device  108  while crossing a busy street. A driver of the vehicle  110  may unable to visually interact with an entertainment system of the vehicle  110  while driving. A surgeon in the hospital  112  may be unable to interrupt a surgical procedure to access life-saving surgical data. In all these example scenarios, and many more, the transducer circuitry  102  can improve user outcomes by converting one or more images to audio with an end-to-end non-autoregressive neural network. 
     The transducer circuitry  102  is applicable to a wide variety of environments beyond those illustrated in  FIG.  1   . For example, the transducer circuitry  102  also provides improved image-to-audio conversion performance in compute devices that have limited memory and/or compute capabilities, such as embedded platforms. Therefore, the transducer circuitry may be particularly useful in performing image-to-audio conversion on compute-constrained embedded platforms (e.g., internet of things devices, smart home devices, etc.). Computing devices are essential to modern-day life, and the transducer circuitry  102  may improve human-computer interaction in any situation in which a user wishes to interact with visual elements of the computing device. Furthermore, the transducer circuitry  102  helps bridge the gap between sighted and visually impaired users by making image-to-audio conversion available on a wider variety of devices and in a wider variety of scenarios. 
     In  FIG.  1   , the transducer circuitry  102  included as part of the example image-to-audio neural network circuitry  103 . The example image-to-audio neural network circuitry  103  is a neural network that converts images to audio. The transducer circuitry  102  and/or the example image-to-audio neural network circuitry  103  may be trained by the training circuitry  104  on training data (e.g., such as the first training data  114   a  and the second training data  114   b ). Training of each respective instance of the transducer circuitry  102  and/or, more generally, the image-to-audio neural network circuitry  103 , may be performed on-device (e.g., at the mobile device  108 ) and/or off-device. For example, the example image-to-audio neural network circuitry  103  may be trained on a first device (e.g., the server  106 ) and transmitted to one or more entities such as the mobile device  108 , the vehicle  110 , and/or the hospital  112 . In some examples, parameters (e.g., parameters of a neural network model) for updating the transducer circuitry  102  and/or the example image-to-audio neural network circuitry  103  may be transmitted between the server  106  and any device connected to the network  116 . In other examples, training of the transducer circuitry  102  and/or the example image-to-audio neural network circuitry  103  may be performed completely on a single device without communication to any other device. The training circuitry  104  will be discussed further in association with  FIGS.  3 ,  4 , and  6   . 
     In the example of  FIG.  1   , a separate instance of the example image-to-audio neural network circuitry  103  (e.g., and the included transducer circuitry  102 ) is included in each of the mobile device  108 , the vehicle  110 , the hospital  112 , and the server  106 . However, in some examples the transducer circuitry  102  may not be included in one or more of the server  106 , the mobile device  108 , the vehicle  110 , and/or the hospital  112 . The structure and function of the transducer circuitry  102  will be described in association with  FIGS.  3 - 5   . 
       FIG.  2 A  is a first illustration  202  of a conversion of text to audio with the transducer circuitry  102  of  FIG.  1   . The first illustration  202  includes a tablet computer  206  that displays an image  208 . The image  208  is an image of the word “CAT”. Traditional screen readers cannot identify and describe the word “CAT” embedded in the image  208  unless metadata such as alt text is present. However, with the transducer circuitry  102 , the word “CAT” embedded in the image  208  can be transformed to audio, providing an accurate description of the image  208 . 
     To identify “CAT” in the image  208  and convert the word within the image  208  into an audio playback  218  of “CAT,” the image is first encoded by image encoder circuitry  210 . The image encoder circuitry  210  extracts fixed-length hidden features from the image  208  (e.g., the word, “CAT”). The transducer circuitry  102  then expands the features into the length of the word&#39;s (e.g., “CAT&#39;s”) Mel-spectrogram. The decoder circuitry  212  (e.g., a variational autoencoder (VAE), any other decoder, etc.) synthesizes the mel-spectrogram based on the expanded features. The waveform  214  of the word “CAT” is then provided to a first speaker  216 , which plays the audio, completing the image-to-audio conversion. A more detailed example of the image-to-audio conversion of the first illustration will be provided in association with  FIG.  4   . 
       FIG.  2 B  is an example second illustration  204  of conversion of image text to audio with the image-to-audio neural network circuitry  103  of  FIG.  1   . The second illustration  204  includes a personal computer  220 , the transducer circuitry  102 , the image-to-audio neural network circuitry  103 , a second speaker  222 , and speech  224 . The personal computer  220  includes neural-network coprocessor circuitry  226  that includes an instance of the image-to-audio neural network circuitry  103  (e.g., and therefore the transducer circuitry  102 ). In the second illustration  204 , an operating system (OS) of the personal computer  220  has failed to fully load. 
     Typical screen readers are subordinate to the OS and may not render text content within images when the OS of the personal computer  220  fails to load. However, in  FIG.  2 B , the image-to-audio neural network circuitry  103  of  FIG.  2 B  is implemented on a dedicated neural network co-processor circuitry  226 , providing operating system independence. Thus, the image-to-audio neural network circuitry  103  that is included  FIG.  2 B  can implement end-to-end image-to-speech conversion independent of OS and/or application failure. 
     In contrast to  FIG.  2 A , the encoder circuitry  210 , the transducer circuitry  102 , and the decoder circuitry  212  of  FIG.  2 B  are all included in the image-to-audio neural network circuitry  103 . Thus, in some examples, the image-to-audio neural network circuitry  103  performs all operations included in an end-to-end conversion of an image to audio, including the operations carried out by the transducer circuitry  102 . 
       FIG.  3    is a block diagram of an example implementation of the transducer circuitry  102  of  FIG.  1    to convert text to audio. The transducer circuitry  102  bridges the gap between image encoder circuitry  210  of  FIG.  2 A  and the decoder circuitry  212  of  FIG.  2 A . The transducer circuitry  102  enables end-to-end training of a non-autoregressive ITS system with limited constraints on the loss function for the image encoder circuitry  210 . The transducer circuitry  102  of  FIG.  2    may be instantiated (e.g., creating an instance of, bring into being for any length of time, materialize, implement, etc.) by processor circuitry such as a central processing unit executing instructions. Additionally or alternatively, the transducer circuitry  102  of  FIG.  1    may be instantiated (e.g., creating an instance of, bring into being for any length of time, materialize, implement, etc.) by an ASIC or an FPGA structured to perform operations corresponding to the instructions. It should be understood that some or all of the circuitry of  FIG.  3    may, thus, be instantiated at the same or different times. Some or all of the circuitry may be instantiated, for example, in one or more threads executing concurrently on hardware and/or in series on hardware. Moreover, in some examples, some or all of the circuitry of  FIG.  3    may be implemented by microprocessor circuitry executing instructions to implement one or more virtual machines and/or containers. 
     The example transducer circuitry  102  includes example image encoder circuitry  210 . In some examples, the image encoder circuitry  210  accesses an image that includes a word. The example image encoder circuitry  210  extracts an ordered list of phonemes of the word. As a result, the image encoder circuitry  210  extracts hidden features (e.g., phonemes) and syntactic information from an example image, generating a fixed-length output. The fixed-length output is generated despite an input word having any number of input phonemes. The image encoder circuitry  210  may pad the phonemes extracted from the word using a placeholder symbol to generate the fixed representation. 
     In some examples the image encoder circuitry  210  is a separate image encoder (e.g., not included in the transducer circuitry  102 ) that provides data to the transducer circuitry  102 . In some examples, the image encoder circuitry  210  is instantiated by processor circuitry executing image encoding instructions and/or configured to perform operations such as those represented by the flowcharts of  FIGS.  5 - 6   . 
     In some examples, the transducer circuitry  102  includes means for providing an image that includes a word to an image encoder that extracts an ordered list of phonemes of the word. For example, the means for providing may be implemented by image encoder circuitry  210 . In some examples, the image encoder circuitry  210  may be instantiated by processor circuitry such as the example processor circuitry  712  of  FIG.  7   . For instance, the image encoder circuitry  210  may be instantiated by the example microprocessor  800  of  FIG.  8    executing machine executable instructions such as those implemented by at least blocks  502  and  504  of  FIG.  5   . In some examples, the image encoder circuitry  210  may be instantiated by hardware logic circuitry, which may be implemented by an ASIC, XPU, or the FPGA circuitry  900  of  FIG.  9    structured to perform operations corresponding to the machine readable instructions. Additionally or alternatively, the image encoder circuitry  210  may be instantiated by any other combination of hardware, software, and/or firmware. For example, the image encoder circuitry  210  may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, an XPU, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to execute some or all of the machine readable instructions and/or to perform some or all of the operations corresponding to the machine readable instructions without executing software or firmware, but other structures are likewise appropriate. 
     The example transducer circuitry  102  includes the example duration determination circuitry  302 . The duration determination circuitry  302  assigns a duration value to a phoneme of the fixed-length representation. As will be described in association with the illustrated example of  FIG.  4   , the duration value corresponds to a length of time the phoneme is expressed in an audio waveform of a word. The duration determination circuitry  302  identifies which phonemes should be actively synthesized in the audio and identifies placeholder symbols that will not be synthesized in the output audio. The duration determination circuitry  302  associates a duration value with one or more phonemes in a fixed-length representation. In some examples, a special padding symbol (e.g., the placeholder symbol “_” of  FIG.  4   ) is assigned a zero value, and that value does not appear in an expanded representation. 
     In some examples, the duration determination circuitry  302  is instantiated by processor circuitry executing duration determining instructions and/or configured to perform operations such as those represented by the flowchart of  FIG.  5   . 
     In some examples, the transducer circuitry  102  includes means for assigning a duration value to a phoneme of the fixed-length representation. For example, the means for assigning may be implemented by duration determination circuitry  302 . In some examples, the duration determination circuitry  302  may be instantiated by processor circuitry such as the example processor circuitry  712  of  FIG.  7   . For instance, the duration determination circuitry  302  may be instantiated by the example microprocessor  800  of  FIG.  8    executing machine executable instructions such as those implemented by at least blocks  506  of  FIG.  5   . In some examples, duration determination circuitry  302  may be instantiated by hardware logic circuitry, which may be implemented by an ASIC, XPU, or the FPGA circuitry  900  of  FIG.  9    structured to perform operations corresponding to the machine readable instructions. Additionally or alternatively, the duration determination circuitry  302  may be instantiated by any other combination of hardware, software, and/or firmware. For example, the duration determination circuitry  302  may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, an XPU, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to execute some or all of the machine readable instructions and/or to perform some or all of the operations corresponding to the machine readable instructions without executing software or firmware, but other structures are likewise appropriate. 
     The example transducer circuitry  102  includes the example sequence expansion circuitry  304 . The example sequence expansion circuitry  304  generates an expanded representation of a fixed-length representation based on the duration value and a desired dimensionality. The example sequence expansion circuitry  304  generates an expanded representation of the fixed-length representation based on the duration values provided by the example duration determination circuitry  302  and a desired dimensionality that is provided by the linear layer circuitry  306 . 
     In some examples, sequence expansion circuitry  304  is instantiated by processor circuitry executing image encoding instructions and/or configured to perform operations such as those represented by the flowchart of  FIG.  5   . 
     In some examples, the sequence expansion circuitry  304  includes means for generating an expanded representation of the fixed-length representation. For example, the means for generating may be implemented by sequence expansion circuitry  304 . In some examples, the sequence expansion circuitry  304  may be instantiated by processor circuitry such as the example processor circuitry  712  of  FIG.  7   . For instance, the sequence expansion circuitry  304  may be instantiated by the example microprocessor  800  of  FIG.  8    executing machine executable instructions such as those implemented by at least block  510  of  FIG.  5   . In some examples, the sequence expansion circuitry  304  may be instantiated by hardware logic circuitry, which may be implemented by an ASIC, XPU, or the FPGA circuitry  900  of  FIG.  9    structured to perform operations corresponding to the machine readable instructions. Additionally or alternatively, the sequence expansion circuitry  304  may be instantiated by any other combination of hardware, software, and/or firmware. For example, the sequence expansion circuitry  304  may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, an XPU, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to execute some or all of the machine readable instructions and/or to perform some or all of the operations corresponding to the machine readable instructions without executing software or firmware. 
     The example transducer circuitry  102  includes the example training circuitry  104 . The example training circuitry  104  may train any of the example linear layer circuitry  306 , the image encoder circuitry  210 , the duration determination circuitry  302 , the example decoder circuitry  212 , and/or the example vocoder circuitry  412  using, for example, stochastic gradient descent. However, any other training algorithm and/or approach to training may additionally or alternatively be used. In some examples, the training circuitry  104  is instantiated by processor circuitry executing image encoding instructions and/or configured to perform operations such as those represented by the flowchart of  FIG.  6   . 
     In some examples, the transducer circuitry  102  includes means for training a neural network. For example, the means for training may be implemented by the training circuitry  104 . In some examples, the training circuitry  104  may be instantiated by processor circuitry such as the example processor circuitry  712  of  FIG.  7   . For instance, the training circuitry  104  may be instantiated by the example microprocessor  800  of  FIG.  8    executing machine executable instructions such as those implemented by at least any of the blocks  602  to  610  of  FIG.  6   . In some examples, the training circuitry  104  may be instantiated by hardware logic circuitry, which may be implemented by an ASIC, XPU, or the FPGA circuitry  900  of  FIG.  9    structured to perform operations corresponding to the machine readable instructions. Additionally or alternatively, the training circuitry  104  may be instantiated by any other combination of hardware, software, and/or firmware. For example, the training circuitry  104  may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, an XPU, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to execute some or all of the machine readable instructions and/or to perform some or all of the operations corresponding to the machine readable instructions without executing software or firmware. 
     The example transducer circuitry  102  includes the linear layer circuitry  306 . The example linear layer circuitry  306  is a bottleneck layer that removes dimensionality mismatches between the image encoder circuitry  210  and the decoder circuitry  212  of  FIG.  2 A . The linear layer circuitry  306  thereby enhances the flexibility of the transducer circuitry  102 , so that various image encoders and various decoders (e.g., mel-spectrogram generators) are interoperable with the transducer circuitry  102 . The example linear layer circuitry  306  (e.g., fully connected layer, dense layer, etc.) transforms input features into output features of a different dimensionality using a weight matrix. In some examples, input features received by the linear layer circuitry  306  are passed in the form of a flattened one-dimension tensor and then multiplied by the weight matrix. In some examples, linear layer circuitry  306  is instantiated by processor circuitry executing image encoding instructions and/or configured to perform operations such as those represented by the flowchart of  FIG.  5   . 
     In some examples, the linear layer circuitry  306  includes means for transforming a dimensionality of a tensor in a neural network. For example, the means for transforming may be implemented by linear layer circuitry  306 . In some examples, the linear layer circuitry  306  may be instantiated by processor circuitry such as the example processor circuitry  712  of  FIG.  7   . For instance, linear layer circuitry  306  may be instantiated by the example microprocessor  800  of  FIG.  8    executing machine executable instructions such as those implemented by at least block  508  of  FIG.  5   . In some examples, the linear layer circuitry  306  may be instantiated by hardware logic circuitry, which may be implemented by an ASIC, XPU, or the FPGA circuitry  900  of  FIG.  9    structured to perform operations corresponding to the machine readable instructions. Additionally or alternatively, the linear layer circuitry  306  may be instantiated by any other combination of hardware, software, and/or firmware. For example, the linear layer circuitry  306  may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, an XPU, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to execute some or all of the machine readable instructions and/or to perform some or all of the operations corresponding to the machine readable instructions without executing software or firmware. 
     The example transducer circuitry additionally includes an example bus  310  and example data storage circuitry  308 . The example bus  310  may provide interconnections between any of the example image encoder circuitry  210 , the example duration determination circuitry  302 , the example sequence expansion circuitry  304 , the example training circuitry  104 , and/or the example linear layer circuitry  306 . The example data storage  308  may include means for storing training data for and/or input/output of any of the example image encoder circuitry  210 , the example duration determination circuitry  302 , the example sequence expansion circuitry  304 , the example training circuitry  104 , and/or the example linear layer circuitry  306 . The example data storage circuitry  308  may store training data for use by the training circuitry  104 , for example. 
     While an example manner of implementing the transducer circuitry  102  of  FIG.  1    is illustrated in  FIG.  3   , one or more of the elements, processes, and/or devices illustrated in  FIG.  3    may be combined, divided, re-arranged, omitted, eliminated, and/or implemented in any other way. Further, the example image encoder circuitry  210 , the example duration determination circuitry  302 , the example sequence expansion circuitry  304 , the example training circuitry  104 , and the example linear layer circuitry  306 , and/or more generally the example transducer circuitry  102  of  FIG.  1    may be implemented by hardware alone or by hardware in combination with software and/or firmware. Thus, for example, any of the example the example image encoder circuitry  210 , the example duration determination circuitry  302 , the example sequence expansion circuitry  304 , the example training circuitry  104 , and the example linear layer circuitry  306 , and/or more generally the example transducer circuitry  102  of  FIG.  1   , could be implemented by processor circuitry, analog circuit(s), digital circuit(s), logic circuit(s), programmable processor(s), programmable microcontroller(s), graphics processing unit(s) (GPU(s)), digital signal processor(s) (DSP(s)), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)), and/or field programmable logic device(s) (FPLD(s)) such as Field Programmable Gate Arrays (FPGAs). Further still, the example transducer circuitry  102  of  FIG.  1    may include one or more elements, processes, and/or devices in addition to, or instead of, those illustrated in  FIG.  3   , and/or may include more than one of any or all of the illustrated elements, processes and devices. 
       FIG.  4    is an illustration of an example system  400  for end-to-end image-to-speech conversion. The system  400  includes an image  208 , image encoder circuitry  210 , transducer circuitry  102 , the decoder circuitry  212  (e.g., VAE decoder circuitry), a mel-spectrogram  410 , vocoder circuitry  412 , the waveform  214 , and the training circuitry  104 . 
     The example transducer circuitry  102  includes a fixed width representation  402 , duration determination circuitry  302 , linear layer circuitry  306 , duration values  404 , a transformed representation  406 , sequence expansion circuitry  304 , and an expanded representation  408 . The example training circuitry  104  includes a ground truth mel-spectrogram  414  and encoder circuitry  416 . 
     The pipeline of the system  400  for end-to-end image-to-speech conversion begins with image  208 . The image  208  includes a series of pixels that include the word “CAT.” Although the input image only includes the single word “CAT”, the input image may be any image that includes one or more words, one or more series of characters, one or more symbols, etc. 
     The image  208  is provided to the example image encoder circuitry  210 . The image encoder circuitry  210  extracts hidden features (e.g., phonemes) and syntactic information from the example image  208 . In this case, the image encoder circuitry  210  extracts the phonemes “K”, “AE”, and “T” from the image  208 . In some examples, the image encoder circuitry  210  includes a pooling layer that extracts global semantic information from hidden features and feeds the global semantic information to a quantity (e.g.,  26 ) of linear layers, wherein each linear layer predicts the one respective output (e.g., i-th linear layer predicts i-th output). 
     The example image encoder circuitry  210  generates a fixed-length output, regardless of any number of input phonemes associated with the word. To produce a fixed-length output, the example image encoder circuitry  210  may insert one or more placeholder characters at the end of the fixed-length representation. For example, if a fixed-length representation of 26 layers is desired, and a word has N phonemes, the last  26 -N layers can be filled with the placeholder character (e.g., “_”). 
     The image encoder circuitry  210  produces the fixed-length representation  402  as an output. The fixed-length representation  402  is an ordered list of phonemes including “K”, “AE”, and “T”. In the example system  400  of  FIG.  4   , the fixed-length representation is six characters. However, the input image  208  includes the word “CAT” that has three phonemes. Therefore, to generate the fixed representation of six characters, the image encoder circuitry  210  has padded the ordered list of phonemes of the fixed-length representation  402  with three placeholder characters (e.g., “_”). It is through padding that the example image encoder circuitry  210  generates a fixed-length representation for any word identified in the input image  208 . Such consistency provides a simplified and consistent flow through the system  400  (e.g., the neural network) regardless of how many phonemes are in the original word identified in the image. 
     The example fixed-length representation  402  is provided to the example duration determination circuitry  302  and to the example linear layer circuitry  306 . The duration determination circuitry  302  determines how many times each feature (e.g., each phoneme) should be repeated. The duration determination circuitry  302  identifies which frame (e.g., a frame as one phoneme, one character, one symbol, etc.) should be actively synthesized in the audio and which frames are placeholder symbols that will not be synthesized in the audio. For example, in  FIG.  4   , the duration determination circuitry  302  is trained to recognize that “_” should have a zero duration. The duration determination circuitry  302  will identify phonemes that will be expressed (in an audio waveform of the word) with a positive value, while placeholder symbols will be zero. 
     The duration determination circuitry  302  may be trained in a supervised manner with a forced aligner. The forced aligner may take a ground truth audio and a corresponding phoneme sequence and align the audio and the ground truth audio. In some examples, the duration determination circuitry  302  includes two convolutional blocks, wherein each block of the two convolutional blocks includes: a) a 1D time-channel separable convolution, b) a 1×1 step-wise convolution, c) a normalization layer, d) a ReLU layer, and e) a dropout layer. For example, a linear layer along with a softplus layer may project a sequence of hidden feature representations (e.g., phonemes of word identified in an image) to a sequence of scalars. The sequence of scalars corresponds to predicted phoneme durations. 
     The example fixed-length representation  402  is also provided to the example linear layer circuitry  306 . The example linear layer circuitry  306  is a bottleneck layer that addresses (e.g., corrects) any dimensionality mismatch between the linear layer circuitry  306  and the decoder circuitry  212 . The linear layer circuitry  306  enhances the flexibility of the transducer circuitry  102  so that various image encoders and various decoders (e.g., mel-spectrogram generators) in the field are compatible with the transducer circuitry  102 . For example, some image encoders may generate output in 512 dimensions, while a corresponding decoder requires a 128 dimension input. To handle this dimensionality mismatch, the linear layer circuitry  306  performs a dimensionality transformation (e.g., thereby serving as a bottleneck). 
     The example duration values  404  represent a duration that each phoneme (e.g., frame, element of the fixed-length representation  402 , etc.) is expressed (e.g., in an audio waveform of the word). In the example of  FIG.  1   , “K” is associated with the value “3”, “AE” is associated with the value “5”, and “T” is associated with the value “2”. Therefore, the feature “K” will be duplicated three times by the sequence expansion circuitry  304 , the feature “AE” will be duplicated five times by the sequence expansion circuitry  304 , and the feature “T” will be duplicated two times by the sequence expansion circuitry  304 . The placeholder symbols “_” are all associated with zero, and therefore will not be included in the expanded representation  408 . 
     The example sequence expansion circuitry  304  may generate an expanded representation of the fixed-length representation based on the duration values provided by the example duration determination circuitry  302  and a desired dimensionality that is provided by the linear layer circuitry  306 . In some examples, the sequence expansion circuitry  304  is a software package that takes a predicted duration and the transformed representation and generates the expanded representation  408  by repeating phonemes a number of times that corresponds to a duration value produced by the duration determination circuitry  302 . The expanded representation  408  illustrates that the phoneme “K” has been repeated three times, the phoneme “AE” has been repeated five times, and the phoneme “T” has been repeated twice. The “_” placeholders (e.g., placeholder symbols) have also been removed from the expanded representation  408 , as the duration for each “_” symbol was determined to be zero by the duration determination circuitry  302 . Furthermore, the dimensionality of the expanded representation  408  has been transformed based on the output of the linear layer circuitry  306 . 
     The output of the transducer circuitry  102  is provided to the decoder circuitry  212 . The decoder circuitry  212  synthesizes the mel-spectrogram  410  based on the expanded representation  408 . The example decoder circuitry  212  may be trained by the training circuitry  104 . The training circuitry  104  is not, however, required for operation of the example system  400  (e.g., when the system has already been trained). The example training circuitry includes a ground truth mel-spectrogram  414  and encoder circuitry  416  (e.g., a VAE encoder). The example ground truth mel-spectrogram  414  can be used to facilitate supervised training of the system  400 . The example encoder circuitry  416  may include a 1D-convolutional layer that is followed by a ReLU activation layer, a normalization layer, and/or a non-causal deep generative model for raw audio waveforms. Any of the example linear layer circuitry  306 , the example transducer circuitry  102 , the example decoder circuitry  212 , and/or the example vocoder circuitry  412  may be trained based on stochastic gradient descent, for example. The example decoder circuitry  212  generates the mel-spectrogram  410 , which is provided as input to the vocoder circuitry  412 . The vocoder circuitry  412  generates the waveform  214 . 
     A flowchart representative of example machine readable instructions, which may be executed to configure processor circuitry to implement the transducer circuitry  102  of  FIG.  1   , is shown in  FIGS.  5 - 6   . The machine readable instructions may be one or more executable programs or portion(s) of an executable program for execution by processor circuitry, such as the processor circuitry  712  shown in the example processor platform  700  discussed below in connection with  FIG.  7    and/or the example processor circuitry discussed below in connection with  FIGS.  8  and/or  9   . The program may be embodied in software stored on one or more non-transitory computer readable storage media such as a compact disk (CD), a floppy disk, a hard disk drive (HDD), a solid-state drive (SSD), a digital versatile disk (DVD), a Blu-ray disk, a volatile memory (e.g., Random Access Memory (RAM) of any type, etc.), or a non-volatile memory (e.g., electrically erasable programmable read-only memory (EEPROM), FLASH memory, an HDD, an SSD, etc.) associated with processor circuitry located in one or more hardware devices, but the entire program and/or parts thereof could alternatively be executed by one or more hardware devices other than the processor circuitry and/or embodied in firmware or dedicated hardware. The machine readable instructions may be distributed across multiple hardware devices and/or executed by two or more hardware devices (e.g., a server and a client hardware device). For example, the client hardware device may be implemented by an endpoint client hardware device (e.g., a hardware device associated with a user) or an intermediate client hardware device (e.g., a radio access network (RAN)) gateway that may facilitate communication between a server and an endpoint client hardware device). Similarly, the non-transitory computer readable storage media may include one or more mediums located in one or more hardware devices. Further, although the example program is described with reference to the flowchart illustrated in  FIGS.  5 - 6   , many other methods of implementing the example transducer circuitry  102  may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., processor circuitry, discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to perform the corresponding operation without executing software or firmware. The processor circuitry may be distributed in different network locations and/or local to one or more hardware devices (e.g., a single-core processor (e.g., a single core central processor unit (CPU)), a multi-core processor (e.g., a multi-core CPU, an XPU, etc.) in a single machine, multiple processors distributed across multiple servers of a server rack, multiple processors distributed across one or more server racks, a CPU and/or a FPGA located in the same package (e.g., the same integrated circuit (IC) package or in two or more separate housings, etc.). 
     The machine readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a fragmented format, a compiled format, an executable format, a packaged format, etc. Machine readable instructions as described herein may be stored as data or a data structure (e.g., as portions of instructions, code, representations of code, etc.) that may be utilized to create, manufacture, and/or produce machine executable instructions. For example, the machine readable instructions may be fragmented and stored on one or more storage devices and/or computing devices (e.g., servers) located at the same or different locations of a network or collection of networks (e.g., in the cloud, in edge devices, etc.). The machine readable instructions may require one or more of installation, modification, adaptation, updating, combining, supplementing, configuring, decryption, decompression, unpacking, distribution, reassignment, compilation, etc., in order to make them directly readable, interpretable, and/or executable by a computing device and/or other machine. For example, the machine readable instructions may be stored in multiple parts, which are individually compressed, encrypted, and/or stored on separate computing devices, wherein the parts when decrypted, decompressed, and/or combined form a set of machine executable instructions that implement one or more operations that may together form a program such as that described herein. 
     In another example, the machine readable instructions may be stored in a state in which they may be read by processor circuitry, but require addition of a library (e.g., a dynamic link library (DLL)), a software development kit (SDK), an application programming interface (API), etc., in order to execute the machine readable instructions on a particular computing device or other device. In another example, the machine readable instructions may need to be configured (e.g., settings stored, data input, network addresses recorded, etc.) before the machine readable instructions and/or the corresponding program(s) can be executed in whole or in part. Thus, machine readable media, as used herein, may include machine readable instructions and/or program(s) regardless of the particular format or state of the machine readable instructions and/or program(s) when stored or otherwise at rest or in transit. 
     The machine readable instructions described herein can be represented by any past, present, or future instruction language, scripting language, programming language, etc. For example, the machine readable instructions may be represented using any of the following languages: C, C++, Java, C #, Perl, Python, JavaScript, HyperText Markup Language (HTML), Structured Query Language (SQL), Swift, etc. 
     As mentioned above, the example operations of  FIGS.  5 - 6    may be implemented using executable instructions (e.g., computer and/or machine readable instructions) stored on one or more non-transitory computer and/or machine readable media such as optical storage devices, magnetic storage devices, an HDD, a flash memory, a read-only memory (ROM), a CD, a DVD, a cache, a RAM of any type, a register, and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the terms non-transitory computer readable medium, non-transitory computer readable storage medium, non-transitory machine readable medium, and non-transitory machine readable storage medium are expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, the terms “computer readable storage device” and “machine readable storage device” are defined to include any physical (mechanical and/or electrical) structure to store information, but to exclude propagating signals and to exclude transmission media. Examples of computer readable storage devices and machine readable storage devices include random access memory of any type, read only memory of any type, solid state memory, flash memory, optical discs, magnetic disks, disk drives, and/or redundant array of independent disks (RAID) systems. As used herein, the term “device” refers to physical structure such as mechanical and/or electrical equipment, hardware, and/or circuitry that may or may not be configured by computer readable instructions, machine readable instructions, etc., and/or manufactured to execute computer readable instructions, machine readable instructions, etc. 
     “Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc., may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended. The term “and/or” when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) B with C, or (7) A with B and with C. As used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. 
     As used herein, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude a plurality. The term “a” or “an” object, as used herein, refers to one or more of that object. The terms “a” (or “an”), “one or more”, and “at least one” are used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions may be implemented by, e.g., the same entity or object. Additionally, although individual features may be included in different examples or claims, these may possibly be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous. 
     Unless specifically stated otherwise, descriptors such as “first,” “second,” “third,” etc., are used herein without imputing or otherwise indicating any meaning of priority, physical order, arrangement in a list, and/or ordering in any way, but are merely used as labels and/or arbitrary names to distinguish elements for ease of understanding the disclosed examples. In some examples, the descriptor “first” may be used to refer to an element in the detailed description, while the same element may be referred to in a claim with a different descriptor such as “second” or “third.” In such instances, it should be understood that such descriptors are used merely for identifying those elements distinctly that might, for example, otherwise share a same name. 
     As used herein, “approximately” and “about” modify their subjects/values to recognize the potential presence of variations that occur in real world applications As used herein, the phrase “in communication,” including variations thereof, encompasses direct communication and/or indirect communication through one or more intermediary components, and does not require direct physical (e.g., wired) communication and/or constant communication, but rather additionally includes selective communication at periodic intervals, scheduled intervals, aperiodic intervals, and/or one-time events. 
     As used herein, “processor circuitry” is defined to include (i) one or more special purpose electrical circuits structured to perform specific operation(s) and including one or more semiconductor-based logic devices (e.g., electrical hardware implemented by one or more transistors), and/or (ii) one or more general purpose semiconductor-based electrical circuits programmable with instructions to perform specific operations and including one or more semiconductor-based logic devices (e.g., electrical hardware implemented by one or more transistors). Examples of processor circuitry include programmable microprocessors, Field Programmable Gate Arrays (FPGAs) that may instantiate instructions, Central Processor Units (CPUs), Graphics Processor Units (GPUs), Digital Signal Processors (DSPs), XPUs, or microcontrollers and integrated circuits such as Application Specific Integrated Circuits (ASICs). For example, an XPU may be implemented by a heterogeneous computing system including multiple types of processor circuitry (e.g., one or more FPGAs, one or more CPUs, one or more GPUs, one or more DSPs, etc., and/or a combination thereof) and application programming interface(s) (API(s)) that may assign computing task(s) to whichever one(s) of the multiple types of processor circuitry is/are best suited to execute the computing task(s). 
       FIG.  5    is a flowchart representative of example machine readable instructions and/or example operations  500  that may be executed and/or instantiated by processor circuitry convert an image to audio. The machine readable instructions and/or the operations  500  of  FIG.  5    begin at block  502 , at which the example image encoder circuitry  210  of  FIG.  2 A  extracts features from an image of a word. At block  504 , the example image encoder circuitry  210  of  FIG.  2 A  pads extracted features with placeholders to generate a fixed-length representation of the features. At block  506 , the example duration determination circuitry  302  of  FIG.  3    assigns repetition counts to segments of the fixed-length representation. 
     At block  508 , the example linear layer circuitry  306  of  FIG.  3    identifies a desired dimensionality. At block  510 , the example sequence expansion circuitry  304  of  FIG.  3    expands the representation based on the repetition counts and the desired dimensionality. At block  512 , the example decoder circuitry  212  of  FIG.  2 A  generates a spectrogram of word from an expanded representation. At block  514 , the example vocoder circuitry  412  of  FIG.  1    synthesizes a waveform from the spectrogram. 
       FIG.  6    is a flowchart representative of example machine readable instructions and/or example operations that may be executed by example processor circuitry to implement the training circuitry  104  of  FIG.  1   . The example operations  600  of  FIG.  6    start at block  602 , at which the example training circuitry  104  of  FIG.  1    trains an image encoder using cross-entropy loss. For example, the training circuitry  104  of  FIG.  1    may measure the performance of a classification model that outputs a probability value (e.g., between 0 and 1). 
     At block  604 , the example training circuitry  104  of  FIG.  1    freezes weights of the encoder. As described herein, freezing a weight (e.g., for a layer of a neural network) refers to disabling gradient computation and backpropagation for the weights associated with the layer. At block  606 , the example training circuitry  104  of  FIG.  1    trains the decoder circuitry  212  of  FIG.  2 A  based on L1 loss and structural similarity loss. At block  608 , the example training circuitry  104  of  FIG.  1    trains the duration prediction circuitry using mean square error. 
     Together, the blocks  606  and  608  train an image-to-audio conversion portions of the transducer circuitry  102  of  FIG.  1   . At block  610 , the example training circuitry  104  of  FIG.  1    adjusts parameters for fine tuning of the transducer circuitry  102 . The operations of block  610  may be omitted in some examples. The instructions end. 
       FIG.  7    is a block diagram of an example processor platform  700  structured to execute and/or instantiate the machine readable instructions and/or the operations of  FIGS.  5 - 6    to implement the transducer circuitry  102  of  FIG.  1   . The processor platform  700  can be, for example, a server, a personal computer, a workstation, a self-learning machine (e.g., a neural network), a mobile device (e.g., a cell phone, a smart phone, a tablet such as an iPad′), a personal digital assistant (PDA), an Internet appliance, a set top box, a headset (e.g., an augmented reality (AR) headset, a virtual reality (VR) headset, etc.) or other wearable device, or any other type of computing device. 
     The processor platform  700  of the illustrated example includes processor circuitry  712 . The processor circuitry  712  of the illustrated example is hardware. For example, the processor circuitry  712  can be implemented by one or more integrated circuits, logic circuits, FPGAs, microprocessors, CPUs, GPUs, DSPs, and/or microcontrollers from any desired family or manufacturer. The processor circuitry  712  may be implemented by one or more semiconductor based (e.g., silicon based) devices. In this example, the processor circuitry  712  implements, the linear layer circuitry  306 , the transducer circuitry  102 , the variational autoencoder (VAE) decoder  212 , the vocoder circuitry  412 , the training circuitry  104 , the duration determination circuitry  302 , the linear layer circuitry  306 , the sequence expansion circuitry  304 , and the encoder circuitry  416 . 
     The processor circuitry  712  of the illustrated example includes a local memory  713  (e.g., a cache, registers, etc.). The processor circuitry  712  of the illustrated example is in communication with a main memory including a volatile memory  714  and a non-volatile memory  716  by a bus  718 . The volatile memory  714  may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS® Dynamic Random Access Memory (RDRAM®), and/or any other type of RAM device. The non-volatile memory  716  may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory  714 ,  716  of the illustrated example is controlled by a memory controller  717 . 
     The processor platform  700  of the illustrated example also includes interface circuitry  720 . The interface circuitry  720  may be implemented by hardware in accordance with any type of interface standard, such as an Ethernet interface, a universal serial bus (USB) interface, a Bluetooth® interface, a near field communication (NFC) interface, a Peripheral Component Interconnect (PCI) interface, and/or a Peripheral Component Interconnect Express (PCIe) interface. 
     In the illustrated example, one or more input devices  722  are connected to the interface circuitry  720 . The input device(s)  722  permit(s) a user to enter data and/or commands into the processor circuitry  712 . The input device(s)  722  can be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, a button, a mouse, a touchscreen, a track-pad, and/or a voice recognition system. 
     One or more output devices  724  are also connected to the interface circuitry  720  of the illustrated example. The output device(s)  724  can be implemented, for example, by display devices (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), a cathode ray tube (CRT) display, an in-place switching (IPS) display, a touchscreen, etc.), a tactile output device, a printer, and/or speaker. The interface circuitry  720  of the illustrated example, thus, typically includes a graphics driver card, a graphics driver chip, and/or graphics processor circuitry such as a GPU. 
     The interface circuitry  720  of the illustrated example also includes a communication device such as a transmitter, a receiver, a transceiver, a modem, a residential gateway, a wireless access point, and/or a network interface to facilitate exchange of data with external machines (e.g., computing devices of any kind) by a network  726 . The communication can be by, for example, an Ethernet connection, a digital subscriber line (DSL) connection, a telephone line connection, a coaxial cable system, a satellite system, a line-of-site wireless system, a cellular telephone system, an optical connection, etc. 
     The processor platform  700  of the illustrated example also includes one or more mass storage devices  728  to store software and/or data. Examples of such mass storage devices  728  include magnetic storage devices, optical storage devices, floppy disk drives, HDDs, CDs, Blu-ray disk drives, redundant array of independent disks (RAID) systems, solid state storage devices such as flash memory devices and/or SSDs, and DVD drives. 
     The machine readable instructions  732 , which may be implemented by the machine readable instructions of  FIGS.  5 - 6    may be stored in the mass storage device  728 , in the volatile memory  714 , in the non-volatile memory  716 , and/or on a removable non-transitory computer readable storage medium such as a CD or DVD. 
       FIG.  8    is a block diagram of an example implementation of the processor circuitry  712  of  FIG.  7   . In this example, the processor circuitry  712  of  FIG.  7    is implemented by a microprocessor  800 . For example, the microprocessor  800  may be a general purpose microprocessor (e.g., general purpose microprocessor circuitry). The microprocessor  800  executes some or all of the machine readable instructions of the flowcharts of  FIGS.  5 - 6    to effectively instantiate the transducer circuitry  102  of  FIG.  1    as logic circuits to perform the operations corresponding to those machine readable instructions. In some such examples, the transducer circuitry  102  of  FIG.  1    is instantiated by the hardware circuits of the microprocessor  800  in combination with the instructions. For example, the microprocessor  800  may be implemented by multi-core hardware circuitry such as a CPU, a DSP, a GPU, an XPU, etc. Although it may include any number of example cores  802  (e.g.,  1  core), the microprocessor  800  of this example is a multi-core semiconductor device including N cores. The cores  802  of the microprocessor  800  may operate independently or may cooperate to execute machine readable instructions. For example, machine code corresponding to a firmware program, an embedded software program, or a software program may be executed by one of the cores  802  or may be executed by multiple ones of the cores  802  at the same or different times. In some examples, the machine code corresponding to the firmware program, the embedded software program, or the software program is split into threads and executed in parallel by two or more of the cores  802 . The software program may correspond to a portion or all of the machine readable instructions and/or operations represented by the flowchart of  FIGS.  5 - 6   . 
     The cores  802  may communicate by a first example bus  804 . In some examples, the first bus  804  may be implemented by a communication bus to effectuate communication associated with one(s) of the cores  802 . For example, the first bus  804  may be implemented by at least one of an Inter-Integrated Circuit (I2C) bus, a Serial Peripheral Interface (SPI) bus, a PCI bus, or a PCIe bus. Additionally or alternatively, the first bus  804  may be implemented by any other type of computing or electrical bus. The cores  802  may obtain data, instructions, and/or signals from one or more external devices by example interface circuitry  806 . The cores  802  may output data, instructions, and/or signals to the one or more external devices by the interface circuitry  806 . Although the cores  802  of this example include example local memory  820  (e.g., Level 1 (L1) cache that may be split into an L1 data cache and an L1 instruction cache), the microprocessor  800  also includes example shared memory  810  that may be shared by the cores (e.g., Level 2 (L2 cache)) for high-speed access to data and/or instructions. Data and/or instructions may be transferred (e.g., shared) by writing to and/or reading from the shared memory  810 . The local memory  820  of each of the cores  802  and the shared memory  810  may be part of a hierarchy of storage devices including multiple levels of cache memory and the main memory (e.g., the main memory  714 ,  716  of  FIG.  7   ). Typically, higher levels of memory in the hierarchy exhibit lower access time and have smaller storage capacity than lower levels of memory. Changes in the various levels of the cache hierarchy are managed (e.g., coordinated) by a cache coherency policy. 
     Each core  802  may be referred to as a CPU, DSP, GPU, etc., or any other type of hardware circuitry. Each core  802  includes control unit circuitry  814 , arithmetic and logic (AL) circuitry (sometimes referred to as an ALU)  816 , a plurality of registers  818 , the local memory  820 , and a second example bus  822 . Other structures may be present. For example, each core  802  may include vector unit circuitry, single instruction multiple data (SIMD) unit circuitry, load/store unit (LSU) circuitry, branch/jump unit circuitry, floating-point unit (FPU) circuitry, etc. The control unit circuitry  814  includes semiconductor-based circuits structured to control (e.g., coordinate) data movement within the corresponding core  802 . The AL circuitry  816  includes semiconductor-based circuits structured to perform one or more mathematic and/or logic operations on the data within the corresponding core  802 . The AL circuitry  816  of some examples performs integer based operations. In other examples, the AL circuitry  816  also performs floating point operations. In yet other examples, the AL circuitry  816  may include first AL circuitry that performs integer based operations and second AL circuitry that performs floating point operations. In some examples, the AL circuitry  816  may be referred to as an Arithmetic Logic Unit (ALU). The registers  818  are semiconductor-based structures to store data and/or instructions such as results of one or more of the operations performed by the AL circuitry  816  of the corresponding core  802 . For example, the registers  818  may include vector register(s), SIMD register(s), general purpose register(s), flag register(s), segment register(s), machine specific register(s), instruction pointer register(s), control register(s), debug register(s), memory management register(s), machine check register(s), etc. The registers  818  may be arranged in a bank as shown in  FIG.  8   . Alternatively, the registers  818  may be organized in any other arrangement, format, or structure including distributed throughout the core  802  to shorten access time. The second bus  822  may be implemented by at least one of an I2C bus, a SPI bus, a PCI bus, or a PCIe bus 
     Each core  802  and/or, more generally, the microprocessor  800  may include additional and/or alternate structures to those shown and described above. For example, one or more clock circuits, one or more power supplies, one or more power gates, one or more cache home agents (CHAs), one or more converged/common mesh stops (CMSs), one or more shifters (e.g., barrel shifter(s)) and/or other circuitry may be present. The microprocessor  800  is a semiconductor device fabricated to include many transistors interconnected to implement the structures described above in one or more integrated circuits (ICs) contained in one or more packages. The processor circuitry may include and/or cooperate with one or more accelerators. In some examples, accelerators are implemented by logic circuitry to perform certain tasks more quickly and/or efficiently than can be done by a general purpose processor. Examples of accelerators include ASICs and FPGAs such as those discussed herein. A GPU or other programmable device can also be an accelerator. Accelerators may be on-board the processor circuitry, in the same chip package as the processor circuitry and/or in one or more separate packages from the processor circuitry. 
       FIG.  9    is a block diagram of another example implementation of the processor circuitry  712  of  FIG.  7   . In this example, the processor circuitry  712  is implemented by FPGA circuitry  900 . For example, the FPGA circuitry  900  may be implemented by an FPGA. The FPGA circuitry  900  can be used, for example, to perform operations that could otherwise be performed by the example microprocessor  800  of  FIG.  8    executing corresponding machine readable instructions. However, once configured, the FPGA circuitry  900  instantiates the machine readable instructions in hardware and, thus, can often execute the operations faster than they could be performed by a general purpose microprocessor executing the corresponding software. 
     More specifically, in contrast to the microprocessor  800  of  FIG.  8    described above (which is a general purpose device that may be programmed to execute some or all of the machine readable instructions represented by the flowchart of  FIGS.  5 - 6    but whose interconnections and logic circuitry are fixed once fabricated), the FPGA circuitry  900  of the example of  FIG.  9    includes interconnections and logic circuitry that may be configured and/or interconnected in different ways after fabrication to instantiate, for example, some or all of the machine readable instructions represented by the flowchart of  FIGS.  5 - 6   . In particular, the FPGA circuitry  900  may be thought of as an array of logic gates, interconnections, and switches. The switches can be programmed to change how the logic gates are interconnected by the interconnections, effectively forming one or more dedicated logic circuits (unless and until the FPGA circuitry  900  is reprogrammed). The configured logic circuits enable the logic gates to cooperate in different ways to perform different operations on data received by input circuitry. Those operations may correspond to some or all of the software represented by the flowcharts of  FIGS.  5 - 6   . As such, the FPGA circuitry  900  may be structured to effectively instantiate some or all of the machine readable instructions of the flowchart of  FIGS.  5 - 6    as dedicated logic circuits to perform the operations corresponding to those software instructions in a dedicated manner analogous to an ASIC. Therefore, the FPGA circuitry  900  may perform the operations corresponding to the some or all of the machine readable instructions of  FIGS.  5 - 6    faster than the general purpose microprocessor can execute the same. 
     In the example of  FIG.  9   , the FPGA circuitry  900  is structured to be programmed (and/or reprogrammed one or more times) by an end user by a hardware description language (HDL) such as Verilog. The FPGA circuitry  900  of  FIG.  9   , includes example input/output (I/O) circuitry  902  to obtain and/or output data to/from example configuration circuitry  904  and/or external hardware  906 . For example, the configuration circuitry  904  may be implemented by interface circuitry that may obtain machine readable instructions to configure the FPGA circuitry  900 , or portion(s) thereof. In some such examples, the configuration circuitry  904  may obtain the machine readable instructions from a user, a machine (e.g., hardware circuitry (e.g., programmed or dedicated circuitry) that may implement an Artificial Intelligence/Machine Learning (AI/ML) model to generate the instructions), etc. In some examples, the external hardware  906  may be implemented by external hardware circuitry. For example, the external hardware  906  may be implemented by the microprocessor  800  of  FIG.  8   . The FPGA circuitry  900  also includes an array of example logic gate circuitry  908 , a plurality of example configurable interconnections  910 , and example storage circuitry  912 . The logic gate circuitry  908  and the configurable interconnections  910  are configurable to instantiate one or more operations that may correspond to at least some of the machine readable instructions of  FIGS.  5 - 6    and/or other desired operations. The logic gate circuitry  908  shown in  FIG.  9    is fabricated in groups or blocks. Each block includes semiconductor-based electrical structures that may be configured into logic circuits. In some examples, the electrical structures include logic gates (e.g., And gates, Or gates, Nor gates, etc.) that provide basic building blocks for logic circuits. Electrically controllable switches (e.g., transistors) are present within each of the logic gate circuitry  908  to enable configuration of the electrical structures and/or the logic gates to form circuits to perform desired operations. The logic gate circuitry  908  may include other electrical structures such as look-up tables (LUTs), registers (e.g., flip-flops or latches), multiplexers, etc. 
     The configurable interconnections  910  of the illustrated example are conductive pathways, traces, vias, or the like that may include electrically controllable switches (e.g., transistors) whose state can be changed by programming (e.g., using an HDL instruction language) to activate or deactivate one or more connections between one or more of the logic gate circuitry  908  to program desired logic circuits. 
     The storage circuitry  912  of the illustrated example is structured to store result(s) of the one or more of the operations performed by corresponding logic gates. The storage circuitry  912  may be implemented by registers or the like. In the illustrated example, the storage circuitry  912  is distributed amongst the logic gate circuitry  908  to facilitate access and increase execution speed. 
     The example FPGA circuitry  900  of  FIG.  9    also includes example Dedicated Operations Circuitry  914 . In this example, the Dedicated Operations Circuitry  914  includes special purpose circuitry  916  that may be invoked to implement commonly used functions to avoid the need to program those functions in the field. Examples of such special purpose circuitry  916  include memory (e.g., DRAM) controller circuitry, PCIe controller circuitry, clock circuitry, transceiver circuitry, memory, and multiplier-accumulator circuitry. Other types of special purpose circuitry may be present. In some examples, the FPGA circuitry  900  may also include example general purpose programmable circuitry  918  such as an example CPU  920  and/or an example DSP  922 . Other general purpose programmable circuitry  918  may additionally or alternatively be present such as a GPU, an XPU, etc., that can be programmed to perform other operations. 
     Although  FIGS.  8  and  9    illustrate two example implementations of the processor circuitry  712  of  FIG.  7   , many other approaches are contemplated. For example, as mentioned above, modern FPGA circuitry may include an on-board CPU, such as one or more of the example CPU  820  of  FIG.  8   . Therefore, the processor circuitry  712  of  FIG.  7    may additionally be implemented by combining the example microprocessor  800  of  FIG.  8    and the example FPGA circuitry  900  of  FIG.  9   . In some such hybrid examples, a first portion of the machine readable instructions represented by the flowcharts of  FIGS.  5 - 6    may be executed by one or more of the cores  802  of  FIG.  8   , a second portion of the machine readable instructions represented by the flowchart of  FIGS.  5 - 6    may be executed by the FPGA circuitry  900  of  FIG.  9   , and/or a third portion of the machine readable instructions represented by the flowcharts of  FIGS.  5 - 6    may be executed by an ASIC. It should be understood that some or all of the transducer circuitry  102  of  FIG.  1    may, thus, be instantiated at the same or different times. Some or all of the circuitry may be instantiated, for example, in one or more threads executing concurrently and/or in series. Moreover, in some examples, some or all of the transducer circuitry  102  of  FIG.  1    may be implemented within one or more virtual machines and/or containers executing on the microprocessor. 
     In some examples, the processor circuitry  712  of  FIG.  7    may be in one or more packages. For example, the microprocessor  800  of  FIG.  8    and/or the FPGA circuitry  900  of  FIG.  9    may be in one or more packages. In some examples, an XPU may be implemented by the processor circuitry  712  of  FIG.  7   , which may be in one or more packages. For example, the XPU may include a CPU in one package, a DSP in another package, a GPU in yet another package, and an FPGA in still yet another package. 
     A block diagram illustrating an example software distribution platform  1005  to distribute software such as the example machine readable instructions  732  of  FIG.  7    to hardware devices owned and/or operated by third parties is illustrated in  FIG.  10   . The example software distribution platform  1005  may be implemented by any computer server, data facility, cloud service, etc., capable of storing and transmitting software to other computing devices. The third parties may be customers of the entity owning and/or operating the software distribution platform  1005 . For example, the entity that owns and/or operates the software distribution platform  1005  may be a developer, a seller, and/or a licensor of software such as the example machine readable instructions  732  of  FIG.  7   . The third parties may be consumers, users, retailers, OEMs, etc., who purchase and/or license the software for use and/or re-sale and/or sub-licensing. In the illustrated example, the software distribution platform  1005  includes one or more servers and one or more storage devices. The storage devices store the machine readable instructions  732 , which may correspond to the example machine readable instructions  500  of  FIG.  5  and  600    of  FIG.  6   , as described above. The one or more servers of the example software distribution platform  1005  are in communication with an example network  1010 , which may correspond to any one or more of the Internet and/or any of the example networks described above. In some examples, the one or more servers are responsive to requests to transmit the software to a requesting party as part of a commercial transaction. Payment for the delivery, sale, and/or license of the software may be handled by the one or more servers of the software distribution platform and/or by a third party payment entity. The servers enable purchasers and/or licensors to download the machine readable instructions  732  from the software distribution platform  1005 . For example, the software, which may correspond to the example machine readable instructions  500  of  FIG.  5  and  600    of  FIG.  6    may be downloaded to the example processor platform  700 , which is to execute the machine readable instructions  732  to implement the transducer circuitry  102  of  FIG.  1   . In some examples, one or more servers of the software distribution platform  1005  periodically offer, transmit, and/or force updates to the software (e.g., the example machine readable instructions  732  of  FIG.  7   ) to ensure improvements, patches, updates, etc., are distributed and applied to the software at the end user devices. 
     From the foregoing, it will be appreciated that example systems, methods, apparatus, and articles of manufacture have been disclosed that convert image to audio. Disclosed systems, methods, apparatus, and articles of manufacture improve the efficiency of using a computing device by presenting a non-autoregressive end-to-end neural network architecture that simplifies hardware design and the ITS inference process, while reducing the memory footprint of ITS inference. Disclosed systems, methods, apparatus, and articles of manufacture are accordingly directed to one or more improvement(s) in the operation of a machine such as a computer or other electronic and/or mechanical device. 
     Example methods, apparatus, systems, and articles of manufacture to convert image to audio are disclosed herein. Further examples and combinations thereof include the following: 
     Example 1 includes an apparatus comprising at least one memory, instructions, and processor circuitry to execute the instructions to identify a word in an image, the word to be converted to an audio waveform, encode the word identified in the image into an ordered list of phonemes, and synthesize the audio waveform of the word based on an output of a neural network that determines a duration that a phoneme of the ordered list of phonemes is to be expressed in the audio waveform. 
     Example 2 includes the apparatus of example 1, wherein the duration is a duration value, and the processor circuitry to execute the instructions to pad the ordered list of phonemes with one or more placeholders to generate a fixed-length representation of the word identified in the image, and generate an expanded representation of the fixed-length representation based on the duration value and a dimensionality. 
     Example 3 includes the apparatus of example 2, wherein the duration value is a first duration value, and the one or more placeholders includes a symbol that is associated with a second duration value of zero. 
     Example 4 includes the apparatus of example 2, wherein the processor circuitry is to execute the instructions to generate a mel-spectrogram from the expanded representation. 
     Example 5 includes the apparatus of example 2, the processor circuitry is a neural network accelerator that is independent of an operating system with which the neural network accelerator is associated. 
     Example 6 includes the apparatus of example 2, wherein the processor circuitry is to train an encoding portion of the neural network based on cross-entropy loss. 
     Example 7 includes the apparatus of example 2, wherein the processor circuitry is to execute the instructions to train a decoding portion of the neural network based on a structural similarity loss. 
     Example 8 includes a non-transitory computer readable storage medium comprising instructions which, when executed by processor circuitry, cause the processor circuitry to identify a word in an image, the word to be converted to an audio waveform, encode the word identified in the image into an ordered list of phonemes, and synthesize the audio waveform of the word based on an output of a neural network that determines a duration that a phoneme of the ordered list of phonemes is to be expressed in the audio waveform. 
     Example 9 includes the non-transitory computer readable medium of example 8, wherein the duration is a duration value, and wherein the instructions, when executed, cause the processor circuitry to pad the ordered list of phonemes with one or more placeholders to generate a fixed-length representation of the word identified in the image, and generate an expanded representation of the fixed-length representation based on the duration value and a dimensionality. 
     Example 10 includes the non-transitory computer readable medium of example 9, wherein the duration value is a first duration value, and wherein the one or more placeholders includes a symbol that is associated with a second duration value of zero. 
     Example 11 includes the non-transitory computer readable medium of example 9, wherein the instructions, when executed, cause the processor circuitry to generate a mel-spectrogram from the expanded representation. 
     Example 12 includes the non-transitory computer readable medium of example 9, wherein the processor circuitry is a neural network accelerator that is independent of an operating system with which the neural network accelerator is associated. 
     Example 13 includes the non-transitory computer readable medium of example 9 wherein the instructions, when executed, cause the processor circuitry to train an encoding portion of the neural network based on cross-entropy loss. 
     Example 14 includes a method comprising identifying a word in an image, the word to be converted to an audio waveform, encoding the word identified in the image into an ordered list of phonemes, and synthesizing the audio waveform of the word based on an output of a neural network that determines a duration that a phoneme of the ordered list of phonemes is to be expressed in the audio waveform. 
     Example 15 includes the method of example 14, wherein the duration is a duration value, and further including padding the ordered list of phonemes with one or more placeholders to generate a fixed-length representation of the word identified in the image, and generating an expanded representation of the fixed-length representation based on the duration value and a dimensionality. 
     Example 16 includes the method of example 15, wherein the duration value is a first duration value, and the one or more placeholders includes a symbol that is associated with a second duration value of zero. 
     Example 17 includes the method of example 15, wherein synthesizing the audio waveform of the word based on the expanded representation includes generating a mel-spectrogram. 
     Example 18 includes the method of example 15, wherein the processor circuitry is a neural network accelerator that is independent of an operating system with which the neural network accelerator is associated. 
     Example 19 includes the method of example 15, further including training an encoding portion of a neural network based on cross-entropy loss. 
     Example 20 includes the method of example 15, further including training a decoding portion of a neural network based on a structural similarity loss. 
     The following claims are hereby incorporated into this Detailed Description by this reference. Although certain example systems, methods, apparatus, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all systems, methods, apparatus, and articles of manufacture fairly falling within the scope of the claims of this patent.